Patent Publication Number: US-7911516-B2

Title: Camera module and electronic apparatus provided with it

Description:
TECHNICAL FIELD 
     The present invention relates to a camera module that is small and thin and has an automatic focusing control function, and an electronic apparatus including this camera module. 
     BACKGROUND ART 
     As a conventional camera module, a camera module is described in JP 2001-78213 A.  FIG. 47  is a sectional view showing a configuration of the camera module described in JP 2001-78213 A. 
     In  FIG. 47 , an imaging system  9010  is an optical processing system that directs light from an object through a diaphragm  9110  and an imaging lens  9100  and forms an image on an imaging surface of an imaging device  9120 . The diaphragm  9110  has three circular apertures  9110   a ,  9110   b  and  9110   c . Light from the object that has left the apertures  9110   a ,  9110   b  and  9110   c  respectively and entered an incident surface  9100   e  of the imaging lens  9100  leaves three lens portions  9100   a ,  9100   b  and  9100   c  of the imaging lens  9100  and then forms three object images on the imaging surface of the imaging device  9120 . 
     A shielding film is formed on a flat portion  9100   d  of an outgoing surface of the imaging lens  9100 . On the incident surface  9100   e  of the imaging lens  9100 , three optical filters  9052   a ,  9052   b  and  9052   c  transmitting light in different wavelength ranges are formed. Further, in the imaging device  9120 , three optical filters  9053   a ,  9053   b  and  9053   c  transmitting light in different wavelength ranges also are formed on three imaging regions  9120   a ,  9120   b  and  9120   c  corresponding to the three lens portions  9100   a ,  9100   b  and  9100   c  of the imaging lens  9100 , respectively. 
     The optical filter  9052   a  and the optical filter  9053   a  have spectral transmittance characteristics mainly transmitting green (indicated by G), the optical filter  9052   b  and the optical filter  9053   b  have spectral transmittance characteristics mainly transmitting red (indicated by R), and further the optical filter  9052   c  and the optical filter  9053   c  have spectral transmittance characteristics mainly transmitting blue (indicated by B). Accordingly, the imaging region  9120   a  is sensitive to green light (G), the imaging region  9120   b  is sensitive to red light (R), and the imaging region  9120   c  is sensitive to blue light (B). 
     In such a camera module with a plurality of imaging lenses, when the distance from the camera module to an object (a subject) varies, the space between a plurality of object images that are formed on the imaging surface of the imaging device  9120  respectively by the plurality of imaging lenses also varies. 
     In the camera module described in JP 2001-78213 A, the space between optical axes of a plurality of image forming systems is set such that the difference between the space between a plurality of object images when the object is present at a virtual subject distance D [m] and the space between a plurality of object images when the object is present at an infinite distance is smaller than twice the pixel pitch of a reference image signal, where the virtual subject distance D [m] is defined as D=1.4/(tan(θ/2)) as a function of shooting angles of view θ [°] of the plurality of image forming systems. In other words, in the camera module described in JP 2001-78213 A, since the space between the optical axes is set such that the difference between both the spaces between the respective object images on the imaging surface is smaller than twice the pixel pitch of the reference signal even when the same image processing as that optimized for shooting an object present at the virtual subject distance D [m] is performed for the shooting of an object present at an infinite distance, it is possible to suppress a color shifting of the image of the object at an infinite distance to an allowable level. 
     In recent years, portable equipment such as camera-equipped mobile phones has become widespread. Accompanying the reduction in size and thickness and the improvement in performance of such portable equipment, there has been a demand for smaller and thinner camera modules with a higher performance. For example, these camera modules are required to have an automatic focusing control function and be capable of not only a landscape shot (shooting an object at a substantially infinite distance) and a portrait shot (shooting an object usually at a distance of several meters) but also a macro shot (shooting an object at a distance of several centimeters to several tens of centimeters). 
     In the camera module described in JP 2001-78213 A, the thickness is reduced by providing a plurality of the lens portions  9100   a ,  9100   b  and  9100   c . However, this conventional camera module has no automatic focusing control function. Also, the virtual subject distance D [m] is set with portrait shots in mind. Therefore, although this conventional camera module can deal with landscape shots and portrait shots, it cannot deal with macro shots. 
     As another conventional camera module for solving the problem that has not been solved by the camera module described in JP 2001-78213 A, a camera module is described in JP 2002-330332 A.  FIG. 48  shows an exemplary image taken by the camera module described in JP 2002-330332 A and its divided sub-regions. In the taken image, a central portion k 0  and detection regions k 1 , k 2 , k 3  and k 4  surrounding the central portion k 0  are formed. Then, parallaxes p 0 , p 1 , p 2 , p 3  and p 4  of the respective detection regions are calculated. From these parallaxes, the one in a predetermined range is extracted. If there are a plurality of parallaxes to be selected, the one in the region closer to the center is selected. Furthermore, using the selected parallax, the entire taken image is corrected. 
     In the conventional camera module described in JP 2002-330332 A, the taken image partially is formed into a plurality of sub-regions, the parallaxes of these sub-regions are calculated, one parallax is selected from them, and the entire taken image is corrected based on this selected parallax. For example, in the case where there are both a person M at a distance of about 2 m from the camera at the center and a person N at a distance of about 10 m on the edge of the taken image as shown in  FIG. 48 , the person M located at the center of the taken image is considered as a subject, and the entire taken image is corrected based on the parallax p 0  in this region k 0 . At this time, since the parallax of the person M is the same as the selected parallax p 0 , the parallactic influence can be corrected, resulting in a beautiful image in the region of the person M. However, since the parallax of the person N is different from the selected parallax p 0 , the parallactic influence cannot be corrected. Therefore, color irregularities are generated in the region of the person N, so that a beautiful image cannot be obtained. 
     DISCLOSURE OF INVENTION 
     Problem to be Solved by the Invention 
     The present invention was made with the foregoing problems in mind, and the object of the present invention is to provide a camera module that can be made smaller and thinner and achieves a beautiful image over an entire image region regardless of a subject distance. 
     A camera module according to the present invention includes a plurality of lens portions, each including at least one lens, a plurality of imaging regions, provided in one-to-one correspondence with the plurality of lens portions, each including a light-receiving surface that is substantially orthogonal to an optical axis direction of its corresponding lens portion, an imaging signal input portion to which a plurality of imaging signals outputted respectively from the plurality of imaging regions are inputted, a block division portion for dividing at least one imaging signal of the plurality of imaging signals into a plurality of blocks, a parallax computing portion for computing for each of the blocks a parallax between images formed respectively by the plurality of lens portions using the imaging signal, and a parallax correcting portion for correcting the plurality of imaging signals based on the parallax and performing an image synthesis. 
     A program according to the present invention is a program for controlling an operation of an image processing portion in a camera module including a plurality of lens portions, each including at least one lens, a plurality of imaging regions, provided in one-to-one correspondence with the plurality of lens portions, each including a light-receiving surface that is substantially orthogonal to an optical axis direction of its corresponding lens portion, an imaging signal input portion to which a plurality of imaging signals outputted respectively from the plurality of imaging regions are inputted, and the image processing portion for performing an image processing of the inputted imaging signal. The program causes the image processing portion to execute a block division process of dividing at least one imaging signal of the plurality of imaging signals into a plurality of blocks, a parallax computing process of computing for each of the blocks a parallax between images formed respectively by the plurality of lens portions using the imaging signal, and a parallax correcting process of correcting the plurality of imaging signals based on the parallax and performing an image synthesis. 
     A program recording medium according to the present invention is a computer-readable recording medium storing the above-described program. 
     EFFECTS OF THE INVENTION 
     The present invention was made with the foregoing problems in mind and can provide a camera module that can be made smaller and thinner and achieves a beautiful image over an entire image region regardless of a subject distance. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a sectional view showing a configuration of a camera module according to Embodiment 1 of the present invention. 
         FIG. 2  is a top view showing a lens of the camera module according to Embodiment 1 of the present invention. 
         FIG. 3  is a top view showing a circuit portion of the camera module according to Embodiment 1 of the present invention. 
         FIG. 4  shows characteristics of color filters of the camera module according to Embodiment 1 of the present invention. 
         FIG. 5  shows characteristics of an IR filter of the camera module according to Embodiment 1 of the present invention. 
         FIG. 6  is a drawing for describing positions of images of an object at an infinite distance in the camera module according to Embodiment 1 of the present invention. 
         FIG. 7  is a drawing for describing positions of images of an object at a finite distance in the camera module according to Embodiment 1 of the present invention. 
         FIG. 8A  is a drawing for describing the relationship between an image when a focus is achieved and a contrast evaluation value in the camera module according to Embodiment 1 of the present invention, and  FIG. 8B  is a drawing for describing the relationship between the image when the focus is not achieved and the contrast evaluation value in the camera module according to Embodiment 1 of the present invention. 
         FIG. 9  is a drawing for describing the relationship between a lens position and the contrast evaluation value in the camera module according to Embodiment 1 of the present invention. 
         FIG. 10  is a block diagram showing the camera module according to Embodiment 1 of the present invention. 
         FIG. 11  is a flowchart showing an operation of the camera module according to Embodiment 1 of the present invention. 
         FIG. 12  is a drawing for describing coordinates of an imaging signal of the camera module according to Embodiment 1 of the present invention. 
         FIG. 13A  shows an original image for describing an edge detection of the camera module according to Embodiment 1 of the present invention,  FIG. 13B  shows an image of a contrast evaluation value for edge detection for describing the edge detection of the camera module according to Embodiment 1 of the present invention, and  FIG. 13C  shows an image of edges for describing the edge detection of the camera module according to Embodiment 1 of the present invention. 
         FIG. 14  is a drawing for describing computation regions of a parallax evaluation value in the camera module according to Embodiment 1 of the present invention. 
         FIG. 15  is a drawing for describing the relationship between a parallax and a parallax evaluation value in the camera module according to Embodiment 1 of the present invention. 
         FIG. 16A  is a drawing for describing the relationship between an actuator operation amount and a contrast evaluation value when the contrast evaluation value is at a maximum without correction in the camera module according to Embodiment 1 of the present invention,  FIG. 16B  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value after positive correction is at a maximum, and  FIG. 16C  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value after negative correction is at a maximum. 
         FIG. 17A  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value before a further positive correction is at a maximum in the case where this further positive correction is performed in the camera module according to Embodiment 1 of the present invention, and  FIG. 17B  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value after a further positive correction is at a maximum in the case where this further positive correction is performed. 
         FIG. 18A  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value before the further negative correction is at a maximum in the case where this further negative correction is performed in the camera module according to Embodiment 1 of the present invention, and  FIG. 18B  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value after the further negative correction is at a maximum in the case where this further negative correction is performed. 
         FIG. 19  is a sectional view showing a configuration of a camera module according to Embodiment 2 of the present invention. 
         FIG. 20  is a block diagram showing the camera module according to Embodiment 2 of the present invention. 
         FIG. 21  is a flowchart showing an operation of the camera module according to Embodiment 2 of the present invention. 
         FIG. 22  is a drawing for describing coordinates of an imaging signal of the camera module according to Embodiment 2 of the present invention. 
         FIG. 23  is a sectional view showing a configuration of a camera module according to Embodiment 3 of the present invention. 
         FIG. 24  is a block diagram showing the camera module according to Embodiment 3 of the present invention. 
         FIG. 25  is a flowchart showing an operation of the camera module according to Embodiment 3 of the present invention. 
         FIG. 26  is a flowchart showing an operation of an automatic focusing control according to Embodiment 3 of the present invention. 
         FIG. 27  is a flowchart showing an operation of a parallax correction according to Embodiment 3 of the present invention. 
         FIG. 28  is a drawing for describing a block division in the camera module according to Embodiment 3 of the present invention. 
         FIG. 29  is a drawing for describing computation regions of a parallax evaluation value in the camera module according to Embodiment 3 of the present invention. 
         FIG. 30  is a drawing for describing computation regions of a correlation value for parallax accuracy evaluation in the camera module according to Embodiment 3 of the present invention. 
         FIG. 31A  is a drawing for describing the state before block re-division in the camera module according to Embodiment 3 of the present invention, and  FIG. 31B  is a drawing for describing the state after the block re-division in the camera module according to Embodiment 3 of the present invention. 
         FIG. 32  is a drawing for describing the relationship between the correlation value for parallax accuracy evaluation and a parallax correction mode flag in the camera module according to Embodiment 3 of the present invention. 
         FIG. 33  is a drawing for describing the relationship between a contrast evaluation value for parallax accuracy evaluation and the parallax correction mode flag in the camera module according to Embodiment 3 of the present invention. 
         FIG. 34  is a flowchart showing an operation of a parallax correcting portion for low correlation according to Embodiment 3 of the present invention. 
         FIG. 35A  shows an original image for describing an edge detection of the parallax correcting portion for low correlation of the camera module according to Embodiment 3 of the present invention,  FIG. 35B  shows an image of a contrast evaluation value for edge detection for describing the edge detection of the parallax correcting portion for low correlation of the camera module according to Embodiment 3 of the present invention, and  FIG. 35C  shows an image of edges for describing the edge detection of the parallax correcting portion for low correlation of the camera module according to Embodiment 3 of the present invention. 
         FIG. 36  is a sectional view showing a configuration of a camera module according to Embodiment 4 of the present invention. 
         FIG. 37  is a block diagram showing the camera module according to Embodiment 4 of the present invention. 
         FIGS. 38A to 38D  are drawings for describing field images of the camera module according to Embodiment 4 of the present invention. 
         FIG. 39  is a flowchart showing an operation of the camera module according to Embodiment 4 of the present invention. 
         FIG. 40  is a timing chart showing the operation of the camera module according to Embodiment 4 of the present invention. 
         FIGS. 41A to 41C  are plan views schematically showing preferable arrangement examples of color filters in the camera module according to Embodiment 4 of the present invention. 
         FIG. 42  is a sectional view showing a configuration of a camera module according to Embodiment 5 of the present invention. 
         FIG. 43  is a block diagram showing the camera module according to Embodiment 5 of the present invention. 
         FIG. 44  is a flowchart showing an operation of the camera module according to Embodiment 5 of the present invention. 
         FIGS. 45A to 45C  are drawings for describing a background replacement in the camera module according to Embodiment 5 of the present invention. 
         FIGS. 46A and 46B  illustrate an example of an electronic apparatus according to Embodiment 6 of the present invention. 
         FIG. 47  is a sectional view showing a configuration of a conventional camera module (described in JP 2001-78213 A). 
         FIG. 48  illustrates an example of an image taken by a conventional camera module (described in JP 2002-330332 A). 
     
    
    
     DESCRIPTION OF THE INVENTION 
     A camera module according to the present invention includes a plurality of lens portions, each including at least one lens, a plurality of imaging regions, provided in one-to-one correspondence with the plurality of lens portions, each including a light-receiving surface that is substantially orthogonal to an optical axis direction of its corresponding lens portion, an imaging signal input portion to which a plurality of imaging signals outputted respectively from the plurality of imaging regions are inputted, a block division portion for dividing at least one imaging signal of the plurality of imaging signals into a plurality of blocks, a parallax computing portion for computing for each of the blocks a parallax between images formed respectively by the plurality of lens portions using the imaging signal, and a parallax correcting portion for correcting the plurality of imaging signals based on the parallax and performing an image synthesis. 
     The position of an object image varies relative to a subject distance. In other words, a parallax increases with decreasing subject distance. Thus, when a plurality of subjects at different distances are shot at the same time, the parallaxes for the individual subjects are different. According to the camera module of the present invention, the parallax is computed for each block, an imaging signal is corrected based on this parallax for each block so as to reduce a parallactic influence, and then an image synthesis is performed. In this manner, even when a plurality of subjects at different distances are shot at the same time, it is possible to correct the parallaxes of the individual subjects suitably, thereby achieving a beautiful image with reduced parallactic influence over an entire image region. 
     It is preferable that the above-described camera module according to the present invention further includes an actuator for changing a relative distance between the plurality of lens portions and the plurality of imaging regions, and a focusing control portion for controlling the actuator based on the parallax. 
     With this preferable configuration, the actuator is operated based on the parallax so as to carry out an automatic focusing control, so that a focus can be achieved with a single actuator operation. Therefore, it is possible to perform an automatic focusing control at a high speed. 
     It is preferable that the above-described camera module according to the present invention further includes a contrast computing portion for computing a contrast based on at least one imaging signal of the plurality of imaging signals and that the focusing control portion controls the actuator based on the parallax and the contrast. 
     With this preferable configuration, since a high-speed automatic focusing control based on the parallax and a highly-accurate automatic focusing control based on the contrast are combined, it is possible to carry out a highly-accurate automatic focusing control at a high speed. 
     In the above-described camera module according to the present invention, it is preferable that the focusing control portion controls the actuator plural times, and the actuator is controlled based on the parallax first and based on the contrast thereafter. 
     With this preferable configuration, first, the actuator is operated based on the parallax so as to carry out an automatic focusing control. Subsequently, the actuator is operated based on the contrast so as to carry out an automatic focusing control. The automatic focusing control based on the parallax is performed at a high speed, because the focus is achieved by a single actuator operation. On the other hand, the automatic focusing control based on the contrast is not susceptible to variations of the actuator and thus is highly accurate, because the focus achievement is judged directly from the image. Consequently, since a coarse adjustment first is made at a high speed by the automatic focusing control based on the parallax and then a fine adjustment is made with high accuracy by the automatic focusing control based on the contrast, it is possible to achieve a high-speed and highly-accurate automatic focusing control. 
     In the above-described camera module according to the present invention, it is preferable that the focusing control portion learns an operation amount with respect to the actuator when the actuator is controlled based on the contrast. 
     With this preferable configuration, learning is conducted so as to correct the operation amount function based on the actuator operation amount executed in the contrast-based automatic focusing control. This makes it possible to correct the operation amount function in a more accurate manner even when there are variations in the actuator, achieve the first more accurate parallax-based automatic focusing control and reduce the number of the fine adjustments thereafter by the contrast-based automatic focusing control, so that a higher-speed automatic focusing control can be achieved. 
     In the above-described camera module according to the present invention, it is preferable that the block division portion divides the at least one imaging signal into the plurality of blocks by detecting outlines of a plurality of image regions from the at least one imaging signal and dividing the at least one imaging signal into the plurality of image regions by the outlines. 
     With this preferable configuration, the outlines are detected, the division into blocks is carried out, the imaging signal is corrected so as to reduce a parallactic influence based on the parallax for each block, and then the image synthesis is performed. This allows a suitable division into blocks, making it possible to achieve a beautiful image with reduced parallactic influence over the entire image region. 
     In the above-described camera module according to the present invention, it is preferable that an outline parallax computing portion is added for computing an outline parallax, which is a parallax between the outlines, based on the imaging signal, and the parallax computing portion computes for each of the blocks the parallax between the images formed respectively by the plurality of lens portions based on the outline parallax. 
     With this preferable configuration, the parallax of the outlines is detected. Based on this parallax, a parallax is computed for each block. Based on this parallax, the imaging signal is corrected so as to reduce the parallactic influence, and then the image synthesis is performed. Thus, it is possible to achieve a beautiful image with reduced parallactic influence over the entire image region. 
     In the above-described camera module according to the present invention, it is preferable that the block division portion divides the at least one imaging signal into a plurality of rectangular blocks. 
     With this preferable configuration, a parallax of a parallax is computed for each block. Based on this parallax, the imaging signal is corrected so as to reduce the parallactic influence, and then the image synthesis is performed. Thus, it is possible to achieve a beautiful image with reduced parallactic influence over the entire image region. 
     It is preferable that the above-described camera module according to the present invention further includes a parallax evaluation value computing portion for computing for each of the plurality of blocks at least one parallax accuracy evaluation value indicating an accuracy of the parallax based on the imaging signal, and that the parallax correcting portion corrects for each of the plurality of blocks the plurality of imaging signals based on the parallax and the parallax accuracy evaluation value and performs the image synthesis. 
     A divided block sometimes contains a plurality of objects at different subject distances. In this case, the parallaxes for the individual objects are different. With this preferable configuration, the accuracy of the parallax computed for each block is judged, and the method for correcting the imaging signal is modified based on this accuracy. In this manner, it is possible to correct an image by an optimal correction method for each block, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     In the above-described camera module according to the present invention, it is preferable that the parallax correcting portion determines for each of the plurality of blocks whether or not this block is to be divided into at least two based on the parallax accuracy evaluation value and performs the image synthesis based on a parallax between divided blocks in the block determined to be divided. 
     With this preferable configuration, the accuracy of the parallax computed for each block is judged, and the block with little accuracy is considered to have mixed parallaxes and divided into at least two blocks. In this manner, it always is possible to correct an image by an optimal block size, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     In the above-described camera module according to the present invention, it is preferable that the parallax evaluation value computing portion computes a first parallax accuracy evaluation value indicating how high a contrast is for each of the plurality of blocks based on at least one imaging signal of the plurality of imaging signals. 
     With this preferable configuration, the accuracy of the parallax computed for each block is computed and evaluated based on the contrast, and the method for correcting the imaging signal is modified based on this contrast. In this manner, it is possible to correct an image by an optimal correction method for each block, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     In the above-described camera module according to the present invention, it is preferable that the parallax evaluation value computing portion computes a second parallax accuracy evaluation value indicating how much images formed respectively by at least two of the lens portions and images shifted therefrom by the parallax are correlated for each of the plurality of blocks using the imaging signal divided into the plurality of blocks. 
     With this preferable configuration, the accuracy of the parallax computed for each block is computed and evaluated using the second parallax accuracy evaluation value indicating how much an image shifted by the parallax is correlated with the original image, and the method for correcting the imaging signal is modified based on the correlation. In this manner, it is possible to correct an image by an optimal correction method for each block, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     In the above-described camera module according to the present invention, it is preferable that, for each of the plurality of blocks, the parallax correcting portion divides this block into at least two when the second parallax accuracy evaluation value is small, and performs the image synthesis based on the parallax between the divided blocks in the block that has been divided. 
     With this preferable configuration, the accuracy of the parallax computed for each block is evaluated using the second parallax accuracy evaluation value indicating how much an image shifted by the parallax is correlated with the original image. Then, the block that is judged to have a small second parallax accuracy evaluation value, namely, a low correlation is divided into at least two blocks. In this manner, it always is possible to correct an image by an optimal block size, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     In the above-described camera module according to the present invention, it is preferable that the parallax evaluation value computing portion computes a first parallax accuracy evaluation value indicating how high a contrast is for each of the plurality of blocks based on at least one imaging signal of the plurality of imaging signals, and a second parallax accuracy evaluation value indicating how much images formed respectively by at least two of the lens portions and images shifted therefrom by the parallax are correlated for each of the plurality of blocks using the imaging signal divided into the plurality of blocks, and for each of the plurality of blocks, the parallax correcting portion divides this block into at least two when the first parallax accuracy evaluation value is large and the second parallax accuracy evaluation value is small, and performs the image synthesis based on the parallax between the divided blocks in the block that has been divided. 
     With this preferable configuration, the accuracy of the computed parallax is evaluated using the first parallax accuracy evaluation value indicating how high a contrast is for each block and the second parallax accuracy evaluation value indicating how much an image shifted by the parallax is correlated with the original image. Then, the block that is judged to have a large first parallax accuracy evaluation value, namely, a high contrast and a small second parallax accuracy evaluation value, namely, a low correlation is divided into at least two blocks. In this manner, it always is possible to correct an image by an optimal block size, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     In the above-described camera module according to the present invention, it is preferable that the imaging signal input portion inputs the plurality of imaging signals for each of a plurality of fields, and the parallax computing portion computes the parallax for each of the blocks in each of the plurality of fields. 
     With this preferable configuration, by computing the parallaxes for individual fields, even in the case where the images of the individual fields are different because shooting times for the individual fields are different when shooting a moving subject, it is possible to compute the parallaxes for the individual fields properly. This allows the image synthesis using these parallaxes, so that a beautiful image with further reduced parallactic influence can be achieved over the entire image region. 
     Also, it is preferable further that the above-described preferable configuration further includes color filters that are provided in one-to-one correspondence with the plurality of lens portions and have filters of plural colors, and that the filters of the same color are provided so as to correspond to at least two of the plurality of lens portions arranged in parallel with a scanning direction of the fields. 
     With this further preferable configuration, even in the case where the images of the individual fields are different because shooting times for the individual fields are different when shooting a moving subject, it is possible to compute the parallaxes for the individual fields more accurately. 
     It is preferable that the above-described camera module according to the present invention further includes another image storing portion for storing another image different from a taken image, and that the parallax correcting portion combines the another image and an image obtained by correcting the imaging signal based on the parallax. 
     With this preferable configuration, by combining the image corrected based on the parallax and another image, it becomes possible to extract an image properly from the corrected image, so that these images can be combined beautifully. 
     In the above-described camera module according to the present invention, it is preferable that the parallax correcting portion performs combining so that a ratio of the image obtained by correcting the imaging signal increases and that of the another image decreases with an increase in the parallax. 
     With this preferable configuration, by combining the image corrected based on the parallax and another image, it becomes possible to extract an image in a part with a large parallax properly from the corrected image, so that these images can be combined beautifully. 
     Further, an electronic apparatus according to the present invention includes the above-described camera module of the present invention. 
     Also, a program according to the present invention is a program for controlling an operation of an image processing portion in a camera module including a plurality of lens portions, each including at least one lens, a plurality of imaging regions, provided in one-to-one correspondence with the plurality of lens portions, each including a light-receiving surface that is substantially orthogonal to an optical axis direction of its corresponding lens portion, an imaging signal input portion to which a plurality of imaging signals outputted respectively from the plurality of imaging regions are inputted, and the image processing portion for performing an image processing of the inputted imaging signal. The program causes the image processing portion to execute a block division process of dividing at least one imaging signal of the plurality of imaging signals into a plurality of blocks, a parallax computing process of computing for each of the blocks a parallax between images formed respectively by the plurality of lens portions using the imaging signal, and a parallax correcting process of correcting the plurality of imaging signals based on the parallax and performing an image synthesis. 
     Moreover, a program recording medium according to the present invention is a computer-readable program recording medium storing the above-described program. 
     According to the program or the program recording medium of the present invention, the parallax is computed for each block, an imaging signal is corrected based on this parallax for each block so as to reduce a parallactic influence, and then an image synthesis is performed. In this manner, even when a plurality of subjects at different distances are shot at the same time, it is possible to correct the parallaxes of the individual subjects suitably, thereby achieving a beautiful image with reduced parallactic influence over an entire image region. 
     The following is a description of specific embodiments of the present invention, with reference to the accompanying drawings. 
     Embodiment 1 
     A camera module according to Embodiment 1 of the present invention achieves a beautiful image over an entire image region by detecting edges, performing a division into blocks and performing a parallax correction based on the parallax for each block. Also, by making a coarse adjustment by an automatic focusing control based on the parallax and a fine adjustment by an automatic focusing control based on a highly accurate contrast, it is possible to carry out a highly accurate automatic focusing control at a high speed. Furthermore, an amount of the fine adjustment is learned so as to improve the accuracy of the next coarse adjustment. 
     The camera module according to Embodiment 1 of the present invention will be described, with reference to the accompanying drawings. 
       FIG. 1  is a sectional view showing a configuration of the camera module according to Embodiment 1 of the present invention. In  FIG. 1 , a camera module  101  includes a lens module portion  110  and a circuit portion  120 . 
     The lens module portion  110  includes a barrel  111 , an upper cover glass  112 , a lens  113 , an actuator fixing portion  114  and an actuator movable portion  115 . The circuit portion  120  includes a substrate  121 , a package  122 , an imaging device  123 , a package cover glass  124  and a system LSI (hereinafter, referred to as an SLSI)  125 . 
     The barrel  111  has a cylindrical shape with its inner wall surface being matte black for preventing light diffusion, and is formed by injection molding of a resin. The upper cover glass  112  has a disc shape, is formed of a transparent resin and fixed firmly to an upper surface of the barrel  111  with an adhesive or the like. The surface of the upper cover glass  112  is provided with a protective film for preventing damage due to friction or the like and an antireflection film for preventing reflection of incident light. 
       FIG. 2  is a top view showing the lens  113  of the camera module according to Embodiment 1 of the present invention. The lens  113  has a substantially disc shape, is formed of glass or a transparent resin and provided with a first lens portion  113   a , a second lens portion  113   b , a third lens portion  113   c  and a fourth lens portion  113   d  that are arranged in a lattice pattern. As shown in  FIG. 2 , an X axis and a Y axis are set along the arrangement directions of the first to fourth lens portions  113   a  to  113   d . In the first lens portion  113   a , the second lens portion  113   b , the third lens portion  113   c  and the fourth lens portion  113   d , light entering from a subject side leaves for a side of the imaging device  123  and forms four images on the imaging device  123 . 
     The actuator fixing portion  114  is fixed firmly to the inner wall surface of the barrel  111  with an adhesive or the like. The actuator movable portion  115  is fixed firmly to an outer peripheral edge of the lens  113  with an adhesive or the like. The actuator fixing portion  114  and the actuator movable portion  115  constitute a voice coil motor. The actuator fixing portion  114  has a permanent magnet (not shown) and a ferromagnetic yoke (not shown), and the actuator movable portion  115  has a coil (not shown). The actuator movable portion  115  is supported elastically by an elastic member (not shown) with respect to the actuator fixing portion  114 . By passing an electric current through the coil of the actuator movable portion  115 , the actuator movable portion  115  moves relatively to the actuator fixing portion  114 , so that the relative distance between the lens  113  and the imaging device  123  along an optical axis varies. 
     The substrate  121  is made of a resin substrate, and the barrel  111  is fixed firmly to an upper surface of the substrate  121  with an adhesive or the like such that a bottom surface of the barrel  111  contacts the upper surface of the substrate  121 . In this way, the lens module portion  110  and the circuit portion  120  are fixed to each other, thus forming the camera module  101 . 
     The package  122  is formed of a resin having metal terminals. Inside the barrel  111 , the package  122  is fixed firmly to the upper surface of the substrate  121  with its metal terminal portion being fixed by soldering or the like. The imaging device  123  is constituted by a first imaging device  123   a , a second imaging device  123   b , a third imaging device  123   c  and a fourth imaging device  123   d . Each of the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d  is a solid-state imaging device such as a CCD sensor or a CMOS sensor. They are arranged such that centers of their light-receiving surfaces substantially match respective centers of optical axes of the first lens portion  113   a , the second lens portion  113   b , the third lens portion  113   c  and the fourth lens portion  113   d  and such that their light-receiving surfaces are substantially orthogonal to the optical axes of their corresponding lens portions. 
     Individual terminals of the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d  are connected to the metal terminals in the bottom portion inside the package  122  with metal wires  127  by wire bonding and connected electrically to the SLSI  125  via the substrate  121 . Light that has left the first lens portion  113   a , light that has left the second lens portion  113   b , light that has left the third lens portion  113   c  and light that has left the fourth lens portion  113   d  respectively form images on the light-receiving surfaces of the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d . Electric information converted from optical information by photodiodes is outputted to the SLSI  125 . 
       FIG. 3  is a top view showing the circuit portion  120  of the camera module according to Embodiment 1 of the present invention. The package cover glass  124  has a flat shape, is formed of a transparent resin and fixed firmly to the upper surface of the package  122  by adhesion or the like. An upper surface of the package cover glass  124  is provided with a first color filter  124   a , a second color filter  124   b , a third color filter  124   c , a fourth color filter  124   d  and a shielding portion  124   e  by deposition or the like. Also, a lower surface of the package cover glass  124  is provided with an infrared ray shielding filter (not shown; hereinafter, referred to as an IR filter) by deposition or the like. 
       FIG. 4  shows characteristics of the color filters of the camera module according to Embodiment 1 of the present invention, and  FIG. 5  shows characteristics of the IR filter of the camera module according to Embodiment 1 of the present invention. The first color filter  124   a  has spectral transmittance characteristics mainly transmitting green indicated by G in  FIG. 4 , the second color filter  124   b  has spectral transmittance characteristics mainly transmitting blue indicated by B in  FIG. 4 , the third color filter  124   c  has spectral transmittance characteristics mainly transmitting red indicated by R in  FIG. 4 , and the fourth color filter has spectral transmittance characteristics mainly transmitting green indicated by G in  FIG. 4 . Further, the IR filter has spectral transmittance characteristics blocking infrared rays indicated by IR in  FIG. 5 . 
     Thus, object light that has entered from an upper portion of the first lens portion  113   a  leaves a lower portion of the first lens portion  113   a , and its green component mainly is transmitted by the first color filter  124   a  and the IR filter so as to form an image on the light-receiving portion of the first imaging device  123   a , and therefore, the first imaging device  123   a  receives the green component of the object light. Object light that has entered from an upper portion of the second lens portion  113   b  leaves a lower portion of the second lens portion  113   b , and its blue component mainly is transmitted by the second color filter  124   b  and the IR filter so as to form an image on the light-receiving portion of the second imaging device  123   b , and therefore, the second imaging device  123   b  receives the blue component of the object light. Object light that has entered from an upper portion of the third lens portion  113   c  leaves a lower portion of the third lens portion  113   c , and its red component mainly is transmitted by the third color filter  124   c  and the IR filter so as to form an image on the light-receiving portion of the third imaging device  123   c , and therefore, the third imaging device  123   c  receives the red component of the object light. Further, object light that has entered from an upper portion of the fourth lens portion  113   d  leaves a lower portion of the fourth lens portion  113   d , and its green component mainly is transmitted by the fourth color filter  124   d  and the IR filter so as to form an image on the light-receiving portion of the fourth imaging device  123   d , and therefore, the fourth imaging device  123   d  receives the green component of the object light. 
     The SLSI  125  controls the passage of an electric current through the coil of the actuator movable portion  115 , drives the imaging device  123 , inputs the electric information from the imaging device  123 , carries out various image processings, communicates with a main CPU and outputs an image to an external part, by a method described later. 
     Now, the relationship between the subject distance and the parallax will be described. Since the camera module according to Embodiment 1 of the present invention has four lens portions (the first lens portion  113   a , the second lens portion  113   b , the third lens portion  113   c  and the fourth lens portion  113   d ), the relative positions of the four object images formed respectively by these four lens portions vary according to the subject distance. 
       FIG. 6  is a drawing for describing positions of images of an object at an infinite distance in the camera module according to Embodiment 1 of the present invention. For the sake of simplicity,  FIG. 6  shows only the first lens portion  113   a , the first imaging device  123   a , the second lens portion  113   b  and the second imaging device  123   b . Incident light L 1  into the first lens portion  113   a  from an object  10  at an infinite distance and incident light L 2  into the second lens portion  113   b  therefrom are in parallel. Accordingly, the distance between the first lens portion  113   a  and the second lens portion  113   b  and that between an object image  11   a  on the first imaging device  123   a  and an object image  11   b  on the second imaging device  123   b  are equal. 
     Here, the optical axes of the first lens portion  113   a , the second lens portion  113   b , the third lens portion  113   c  and the fourth lens portion  113   d  substantially match the centers of the light-receiving surfaces of the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d , respectively. Thus, the relative positional relationships between the centers of the respective light-receiving surfaces of the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d  and respective images of the object at an infinite distance formed on these light-receiving surfaces are the same for all the imaging devices. In other words, there is no parallax. 
       FIG. 7  is a drawing for describing positions of images of an object at a finite distance in the camera module according to Embodiment 1 of the present invention. For the sake of simplicity,  FIG. 7  shows only the first lens portion  113   a , the first imaging device  123   a , the second lens portion  113   b  and the second imaging device  123   b . Incident light L 1  into the first lens portion  113   a  from an object  12  at a finite distance and incident light L 2  into the second lens portion  113   b  therefrom are not in parallel. Accordingly, the distance between an object image  13   a  on the first imaging device  123   a  and an object image  13   b  on the second imaging device  123   b  is greater than that between the first lens portion  113   a  and the second lens portion  113   b . Thus, the relative positional relationships between the centers of the respective light-receiving surfaces of the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d  and respective images of the object at a finite distance formed on these light-receiving surfaces are different from one imaging device to another. In other words, there is a parallax. 
     When A represents the distance to the object image  12  (the subject distance), D represents the distance between the first lens portion  113   a  and the second lens portion  113   b  and  f  represents a focal length of the lens portions  113   a  and  113   b , since a right triangle whose two sides forming a right angle have lengths A and D and that whose two sides forming a right angle have lengths f and Δ in  FIG. 7  are similar to each other, the parallax Δ is expressed by Equation (1) below. The same relationship holds true for the other lens portions. In this manner, the relative positions of the four object images formed respectively by the four lens portions  113   a ,  113   b ,  113   c  and  113   d  vary according to the subject distance. For example, when the subject distance A decreases, the parallax Δ increases.
 
Δ= f·D/A   (1)
 
     Now, the relationship between a contrast and the focal length will be described. 
       FIG. 8A  is a drawing for describing the relationship between an image when a focus is achieved (a focus is adjusted) and a contrast evaluation value in the camera module according to Embodiment 1 of the present invention, and  FIG. 8B  is a drawing for describing the relationship between the image when the focus is not achieved (the focus is not adjusted) and the contrast evaluation value in the camera module according to Embodiment 1 of the present invention. 
     The drawings on the left in  FIGS. 8A and 8B  show images when shooting a rectangle whose left half is white and right half is black. As in the drawing on the left in  FIG. 8A , when the focus is achieved, an outline of the image is clear, resulting in a high contrast. On the other hand, as in the drawing on the left in  FIG. 8B , when the focus is not achieved, the outline of the image is blurred, resulting in a low contrast. 
     The drawings on the right in  FIGS. 8A and 8B  show results of subjecting information signals of the left-hand drawings to a band-pass filter (BPF). The horizontal axis indicates a position in an X-axis direction, and the vertical axis indicates an output value after BPF. As in the drawing on the right in  FIG. 8A , a signal amplitude after BPF is large when the focus is achieved. On the other hand, as in the drawing on the right in  FIG. 8B , the signal amplitude after BPF is small when the focus is not achieved. Here, the signal amplitude after BPF is defined as a contrast evaluation value indicating how high the contrast is. Then, the contrast evaluation value is large when the focus is achieved as shown in the drawing on the right in  FIG. 8A , whereas the contrast evaluation value is small when the focus is not achieved as shown in the drawing on the right in  FIG. 8B . 
       FIG. 9  is a drawing for describing the relationship between a lens position and the contrast evaluation value in the camera module according to Embodiment 1 of the present invention. At the time of shooting an object, when the distance between the lens  113  and the imaging device  123  is small (at z 1 ), the focus is not achieved, so that the contrast evaluation value is small. As the distance between the lens  113  and the imaging device  123  is extended gradually, the contrast evaluation value increases gradually. When the focus is achieved (at z 2 ), the contrast evaluation value is at a maximum. Further, as the distance between the lens  113  and the imaging device  123  is extended gradually (at z 3 ), the focus is no longer achieved, so that the contrast evaluation value decreases. As described above, when the focus is achieved, the contrast evaluation value becomes maximal. 
     Now, an operation of the camera module according to Embodiment 1 of the present invention will be described.  FIG. 10  is a block diagram showing the camera module according to Embodiment 1 of the present invention. The SLSI  125  includes a system control portion  131 , an imaging device driving portion  132 , an imaging signal input portion  133 , an actuator operation amount output portion  134 , an image processing portion  135  and an input/output portion  136 . Also, the circuit portion  120  includes an amplifier  126  in addition to the configuration described above. 
     The amplifier  126  applies a voltage according to an output from the actuator operation amount output portion  134  to the coil of the actuator movable portion  115 . 
     The system control portion  131  is configured by a CPU (central processing unit), a memory, etc. and controls the entire SLSI  125 . The imaging device driving portion  132  is configured by a logic circuit, etc., generates a signal for driving the imaging device  123  and applies a voltage according to this signal to the imaging device  123 . 
     The imaging signal input portion  133  includes a first imaging signal input portion  133   a , a second imaging signal input portion  133   b , a third imaging signal input portion  133   c  and a fourth imaging signal input portion  133   d . The first imaging signal input portion  133   a , the second imaging signal input portion  133   b , the third imaging signal input portion  133   c  and the fourth imaging signal input portion  133   d  are each configured by connecting a CDS circuit (correlated double sampling circuit), an AGC (automatic gain controller) and an ADC (analog digital converter) in series. They are connected to the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d , respectively, supplied with electric signals from them, remove fixed noises with the CDS circuit, adjust gains with the AGC, convert analog signals into digital values with the ADC and write them into the memory in the system control portion  131 . 
     The actuator operation amount output portion  134  is configured by a DAC (digital analog converter) and outputs a voltage signal according to a voltage to be applied to the coil of the actuator movable portion  115 . 
     The image processing portion  135  is configured so as to include a logic circuit, a DSP or both of the logic circuit and the DSP and carries out various image processings utilizing memory information in the system control portion  131  according to a predetermined program control. The image processing portion  135  includes an edge detecting portion  141 , a block division portion  142 , a parallax computing portion  143 , a parallax correcting portion  144 , a parallax-based automatic focusing control portion  145 , an actuator control portion  146 , a contrast-based automatic focusing control portion  147 , a portion  148  for computing a contrast evaluation value for automatic focusing control and an actuator operation amount function correcting portion  149 . 
     The input/output portion  136  communicates with the main CPU (not shown) and outputs an image signal to the main CPU, an external memory (not shown) and an external display (not shown) such as a liquid crystal display. 
       FIG. 11  is a flowchart showing the operation of the camera module according to Embodiment 1 of the present invention. The camera module  101  is operated as per this flowchart by the system control portion  131  of the SLSI  125 . 
     In Step S 100 , the operation starts. For example, the main CPU (not shown) senses that a shutter button or the like is pressed down, and instructs the camera module to start operating via the input/output portion  136 , whereby the camera module  101  starts operating. Next, Step S 110  is executed. 
     In Step S 110 , shooting is executed. On the instruction of the system control portion  131 , the imaging device driving portion  132  outputs signals for an electronic shutter and transferring as necessary. The first imaging signal input portion  133   a , the second imaging signal input portion  133   b , the third imaging signal input portion  133   c  and the fourth imaging signal input portion  133   d  input imaging signals, which are analog signals of the images outputted respectively by the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d , in synchronization with the signals generated by the imaging device driving portion  132 , remove fixed noises with the CDS, adjust input gains automatically with the AGC, convert the analog signals into digital values with the ADC, and write the digital values into the memory at a predetermined address in the system control portion  131  as a first imaging signal I 1 ( x,y ), a second imaging signal I 2 ( x,y ), a third imaging signal I 3 ( x,y ) and a fourth imaging signal I 4 ( x,y ).  FIG. 12  is a drawing for describing coordinates of the imaging signal of the camera module according to Embodiment 1 of the present invention. I 1 ( x,y ) indicates the first imaging signal, which is the x-th signal in a horizontal direction and the y-th signal in a vertical direction. In an image to be inputted, the number of pixels in the vertical direction is H, the number of pixels in the horizontal direction is L, and the total number of pixels is H×L. x varies from 0 to L−1, and y varies from 0 to H−1. This also holds true for the second imaging signal I 2 ( x,y ), the third imaging signal I 3 ( x,y ) and the fourth imaging signal I 4 ( x,y ). In other words, I 2 ( x,y ), I 3 ( x,y ) and I 4 ( x,y ) respectively indicate the second imaging signal, the third imaging signal and the fourth imaging signal, each of which is the x-th signal in the horizontal direction and the y-th signal in the vertical direction. In an image to be inputted, the number of pixels in the vertical direction is H, the number of pixels in the horizontal direction is L, and the total number of pixels is H×L. x varies from 0 to L−1, and y varies from 0 to H−1. Next, Step S 121  is executed. 
     In Step S 121  and Step S 122 , the edge detecting portion  141  utilizes data in the memory in the system control portion  131  and detects edges. Then, the edge detecting portion  141  writes the result into the memory in the system control portion  131 . A detail will be described in the following. 
     In Step S 121 , a contrast evaluation value for edge detection is computed. This computation is performed only for the first imaging signal. Laplacian is computed as per Equation (2) below and further is subjected spatially to a LPF (low-pass filter) as per Equation (3) below, and the result is given as a contrast evaluation value for edge detection C 2 ( x,y ).  FIG. 13A  shows an original image for describing the edge detection of the camera module according to Embodiment 1 of the present invention, and  FIG. 13B  shows an image of the contrast evaluation value for edge detection for describing the edge detection of the camera module according to Embodiment 1 of the present invention. From Equations (2) and (3), the contrast evaluation value for edge detection C 2 ( x,y ) of the original image in  FIG. 13A  is calculated, which is shown in  FIG. 13B . It should be noted that black indicates where an absolute value of Equation (3) is large in  FIG. 13B . Next, Step S 122  is executed.
 
 C 1( x,y )= I 1( x− 1 ,y )+ I 1( x+ 1 ,y )+ I 1( x,y− 1)+ I 1( x,y+ 1)−4 I 1( x,y )  (2)
 
     
       
         
           
             
               
                 
                   
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     In Step S 122 , the edges are detected.  FIG. 13C  shows an image of the edges for describing the edge detection of the camera module according to Embodiment 1 of the present invention. By sensing a zero crossing (a point at which a value changes from positive to negative and a point at which a value changes from negative to positive) of the contrast evaluation value for edge detection C 2 ( x,y ) in  FIG. 13B , it is possible to detect the edges as shown in  FIG. 13C . Next, Step S 130  is executed. 
     In Step S 130 , the block division portion  142  utilizes data in the memory in the system control portion  131  and carries out a division into blocks. Then, the block division portion  142  writes the result into the memory in the system control portion  131 . As shown in  FIG. 13C , numbers such as B 0 , B 1 , . . . , Bi, . . . , Bn are given to regions surrounded by the edges. Incidentally, in order to prevent erroneous detection and loss of the edges due to noise or the like, the edges also may be corrected using a dilation algorithm or an erosion algorithm. Next, Step S 140  is executed. 
     In Step S 140 , the parallax computing portion  143  utilizes data in the memory in the system control portion  131  and computes a parallax value for each block. Then, the parallax computing portion  143  writes the parallax value into the memory in the system control portion  131 . First, for each block (B 0 , B 1 , . . . , Bi, . . . , Bn), a parallax evaluation value (R 0 ( k ), R 1 ( k ), . . . , Ri(k), . . . , Rn(k); k=0, 1, . . . , m) is computed.  FIG. 14  is a drawing for describing computation regions of the parallax evaluation value in the camera module according to Embodiment 1 of the present invention. A region indicated by Bi (also indicated by I 1 ) is the i-th block obtained from the first imaging signal I 1  in Step S 130 . A region indicated by I 4  is a region obtained by moving Bi by k in an x direction and k in a y direction. Then, for all image signals I 1 ( x,y ) and I 4 ( x,y ) in these regions, the sum of absolute difference expressed by Equation (4) below is computed as a parallax evaluation value Ri(k).
 
 Ri ( k )=ΣΣ| I 1( x,y )− I 4( x−k,y−k )|  (4)
 
     This parallax evaluation value Ri(k) indicates how the first image signal I 1  of the i-th block B 1  and the fourth image signal I 4  in the region shifted therefrom by (k, k) respectively in the x and y directions are correlated. The smaller the parallax evaluation value Ri(k) is, the higher the correlation is (the higher the degree of similarity is).  FIG. 15  is a drawing for describing the relationship between the parallax and the parallax evaluation value in the camera module according to Embodiment 1 of the present invention. As shown in  FIG. 15 , the parallax evaluation value Ri(k) varies with the value of k and is at a minimum when k=Δi. This indicates that an image signal of a block obtained by moving the i-th block Bi of the fourth image signal I 4  by (−Δi, −Δi) respectively in the x and y directions has the highest correlation with (the highest degree of similarity to) the first image signal I 1 . Accordingly, it is understood that the parallax in the x and y directions between the first imaging signal I 1  and the fourth imaging signal I 4  for the i-th block is (Δi, Δi). In the following, this Δi is referred to as a parallax value Δi of the i-th block Bi. In this manner, the parallax values Δi of all the blocks Bi from i=0 to i=n are obtained. Next, Step S 151  is executed. 
     In Step S 151  and Step S 152 , a preview image is outputted. 
     In Step S 151 , the parallax correcting portion  144  utilizes data in the memory in the system control portion  131 , carries out a parallax correction for each block using the parallax value corresponding to this block, and then performs an image synthesis. Then, the parallax correcting portion  144  writes the result into the memory in the system control portion  131 . Since the first imaging device  123   a  and the fourth imaging device  123   d  mainly receive the green component of the object light, the first imaging signal I 1  and the fourth imaging signal I 4  are information signals of the green component of the object light. Also, since the second imaging device  123   b  mainly receives the blue component of the object light, the second imaging signal I 2  is an information signal of the blue component of the object light. Further, since the third imaging signal  123   c  mainly receives the red component of the object light, the third imaging signal I 3  is an information signal of the red component of the object light. Since the parallax between the first imaging device  123   a  and the fourth imaging device  123   d  is calculated to be (Δi, Δi), G(x,y) indicating the intensity of green at the pixel coordinates (x,y) is given by an average of the first imaging signal I 1 ( x,y ) and the fourth imaging signal I 4 ( x−Δi,y−Δi ) as in Equation (5) below. Also, since the parallax between the first imaging device  123   a  and the second imaging device  123   b  is calculated to be (Δi, 0), B(x,y) indicating the intensity of blue at the pixel coordinates (x,y) is given by the second imaging signal I 2 ( x−Δi,y ) as in Equation (6) below. Further, since the parallax between the first imaging device  123   a  and the third imaging device  123   c  is calculated to be (0,Δi), R(x,y) indicating the intensity of red at (x,y) is given by the third imaging signal I 3 ( x,y−Δi ) as in Equation (7) below. Incidentally, the parallax value Δi of the block Bi including the pixel coordinates (x,y) is used as the parallax value Δi. Next, Step S 152  is executed.
 
 G ( x,y )=[ I 1( x,y )+ I 4( x−Δi,y−Δi )]/2  (5)
 
 B ( x,y )= I 2( x−Δi,y )  (6)
 
 R ( x,y )= I 3( x,y−Δi )  (7)
 
     In Step S 152 , an image is outputted. The input/output portion  136  outputs G(x,y), B(x,y) and R(x,y), which are data in the memory in the system control portion  131 , to the main CPU (not shown) and the external display (not shown). It should be noted that a luminance signal or a color difference signal, for example, may be outputted instead of G(x,y), B(x,y) and R(x,y). Also, values after the image processings such as a white-balance correction and a γ correction may be outputted. Next, S 161  is executed. 
     In Steps S 161 , S 162  and S 163 , and S 164  an automatic focusing control is carried out using the parallax value. 
     In Step  161 , the parallax-based automatic focusing control portion  145  selects a block for automatic focusing control based on the data in the memory in the system control portion  131 . Then, the parallax-based automatic focusing control portion  145  writes the result into the memory in the system control portion  131 . For example, at least one block (for example, three blocks Bj 1 , Bj 2  and Bj 3 ) near the center of the image region is selected. Incidentally, these blocks do not have to be the ones near the center but may be the ones selected by reflecting an intention of a user operating the camera (for example, by detecting a viewpoint direction with a sensor). Next, Step S 162  is executed. 
     In Step S 162 , a positional instruction of the actuator is computed. In the example described above, an average of the parallax values Δj 1 , Δj 2  and Δj 3  of the blocks Bj 1 , Bj 2  and Bj 3  serves as a parallax value for automatic focusing control Δaf as in Equation (8) below. It should be noted that weights may be assigned suitably by information such as how large the areas of the blocks are or whether the blocks are close to the center. Further, as in Equation (9) below, a positional instruction Xact of the actuator is computed. Incidentally, the positional instruction Xact indicates an instruction of a position in a direction toward the subject with respect to the position at which an infinity object is focused. Next, Step S 163  is executed.
 
Δ af =(Δ j 1 +Δj 2 +Δj 3)/3  (8)
 
 X act= kx·Δaf   (9)
 
     In Step S 163 , the actuator control portion  146  computes an actuator operation amount (a voltage to be applied to the coil of the actuator movable portion  115 ) Vact using an operation amount function expressed by Equation (10) below. Also, the actuator control portion  146  stores the actuator operation amount as Vact 0  for learning an operation amount function as described later. Next, Step S 164  is executed.
 
 V act= ka·X act+ kb   (10)
 
Vact0=Vact  (10′)
 
     In Step S 164 , the actuator is operated. The actuator operation amount output portion  134  changes a voltage signal to be outputted so that a voltage applied to the coil (not shown) of the actuator movable portion  115  via the amplifier  126  is Vact. Next, Step S 171  is executed. 
     In Steps S 171 , S 172 , S 173 , S 174 , S 175  and S 176 , the contrast-based automatic focusing control portion  147  carries out an automatic focusing control using the contrast. As shown in  FIG. 9  described earlier, the contrast evaluation value is at a maximum at the position where the focus is achieved. Using this principle, a search is made for an actuator operation amount with which the contrast evaluation value becomes maximal. 
     In Step S 171 , a contrast evaluation value for automatic focusing control without a correction of the actuator operation amount is created. Step S 171  includes Step S 171   c  and Step S 171   d . First, Step S 171   c  is executed. 
     In Step S 171   c , shooting is executed. This operation is similar to that in Step S 110 . However, it may be possible to transfer only the imaging signal I 1  of the block for automatic focusing control selected in S 161  out of the imaging signals I 1  from the first imaging device  123   a . In this case, a transfer time can be shortened compared with the case of transferring all the imaging signals. Next, Step S 171   d  is executed. 
     In Step S 171   d , the portion  148  for computing a contrast evaluation value for automatic focusing control creates a contrast evaluation value for automatic focusing control using the data in the memory in the system control portion  131 . This computation is performed only for the first imaging signal I 1  of the block for automatic focusing control. An absolute value of Laplacian is computed as per Equation (11) below and further is subjected spatially to a LPF (low-pass filter) as per Equation (12) below, and the result is averaged in the block for automatic focusing control as per Equation (13) below, thereby obtaining a contrast evaluation value for automatic focusing C 5 . Here, N represents the number of C 4 ( x,y ) in the block for automatic focusing control. Then, as per Equation (14) below, the contrast evaluation value C 5  at this time is given as C 50  and written into the memory in the system control portion  131 . Next, Step S 172  is executed. 
     
       
         
           
             
               
                 
                   
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     In Step  172 , the contrast evaluation value for automatic focusing control at the time of positive correction of the actuator operation amount is created. Step S 172  includes Step S 172   a , Step S 172   b , Step S 172   c  and Step S 172   d . First, Step S 172   a  is executed. 
     In Step S 172   a , an actuator operation amount at the time of positive correction Vact is obtained by adding dVact to the actuator operation amount (the voltage to be applied to the coil of the actuator fixing portion  114 ) without a correction Vact 0  as per Equation (15) below and stored in the memory as Vactp as per Equation (16) below. Next, Steps S 172   b , S 172   c  and S 172   d  are executed.
 
 V act= V act0 +dV act  (15)
 
Vactp=Vact  (16)
 
     In Step S 172   b , the actuator is operated. In Step S 172   c , shooting is executed. In Step S 172   d , the contrast evaluation value for automatic focusing control is created. The operation in Step S 172   b  is similar to that in Step S 164 . Also, the operations in Steps S 172   c  and S 172   d  are similar to those in Steps S 171   c  and S 171   d . The contrast evaluation value C 5  is given as a contrast evaluation value for automatic focusing after positive correction C 5   p  as per Equation (17) below and written into the memory in the system control portion  131 . Next, Step S 173  is executed.
 
C5p=C5  (17)
 
     In Step  173 , the contrast evaluation value for automatic focusing control at the time of negative correction of the actuator operation amount is created. Step S 173  includes Step S 173   a , Step S 173   b , Step S 173   c  and Step S 173   d . First, Step S 173   a  is executed. 
     In Step S 173   a , an actuator operation amount at the time of negative correction Vact is obtained by subtracting dVact from the actuator operation amount (the voltage to be applied to the coil of the actuator fixing portion  114 ) without a correction Vact 0  as per Equation (18) below and stored in the memory as Vactn as per Equation (19) below. Next, Steps S 173   b , S 173   c  and S 173   d  are executed.
 
 V act= V act0− dV act  (18)
 
Vactn=Vact  (19)
 
     In Step S 173   b , the actuator is operated. In Step S 173   c , shooting is executed. In Step S 173   d , the contrast evaluation value for automatic focusing control is created. The operations similar to those in Step S 172   b , Step S 172   c  and Step S 172   d  are carried out. The contrast evaluation value C 5  is given as a contrast evaluation value for automatic focusing after negative correction C 5   n  as per Equation (20) below and written into the memory in the system control portion  131 . Next, Step S 174  is executed.
 
C5n=C5  (20)
 
     In Step S 174 , the contrast evaluation values for focusing control are evaluated. C 50 , C 5   p  and C 5   n  are compared, and the operation is branched according to which has the maximum value. 
     When C 50  is the maximum value, the following operation is carried out, and then Step S 181  is executed.  FIG. 16A  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value is at a maximum without correction in the camera module according to Embodiment 1 of the present invention. As shown in  FIG. 16A , the actuator operation amount without correction Vact 0  gives substantially the maximum value of the contrast evaluation value for automatic focusing control C 5 . Therefore, as in Equation (21) below, Vact 0  serves as a final actuator operation amount Vactf.
 
Vactf=Vact0(when C50 is the maximum value)  (21)
 
     When C 5   p  is the maximum value, the following operation is carried out, and then Step S 175  is executed.  FIG. 16B  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value after positive correction is at a maximum in the camera module according to Embodiment 1 of the present invention. As shown in  FIG. 16B , the actuator operation amount after positive correction Vactp or the actuator operation amount after a further positive correction Vact gives substantially the maximum value of the contrast evaluation value for automatic focusing control C 5 . Therefore, the actuator operation amount is corrected further toward the positive side, and a search is made for the maximum value. Incidentally, as in Equation (22) below, C 5   p  serves as a previous value and is stored as C 5   pp.  
 
C5pp=C5p  (22)
 
     When C 5   n  is the maximum value, the following operation is carried out, and then Step S 176  is executed.  FIG. 16C  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value after negative correction is at a maximum in the camera module according to Embodiment 1 of the present invention. As shown in  FIG. 16C , the actuator operation amount after negative correction Vactn or the actuator operation amount after a further negative correction Vact gives substantially the maximum value of the contrast evaluation value for automatic focusing control C 5 . Therefore, the actuator operation amount is corrected further toward the negative side, and a search is made for the maximum value. Incidentally, as in Equation (23) below, C 5   n  serves as a previous value and is stored as C 5   np.  
 
C5np−C5n  (23)
 
     In Step S 175 , the contrast evaluation value for automatic focusing at the time of the further positive correction is created and evaluated. Step S 175  includes Step S 175   a , Step S 175   b , Step S 175   c , Step S 175   d  and Step S 175   e . First, Step S 175   a  is executed. 
     In Step S 175   a , an actuator operation amount at the time of positive correction Vact is obtained by adding dVact to the actuator operation amount (the voltage to be applied to the coil of the actuator fixing portion  114 ) after the previous positive correction Vactp as per Equation (24) below and stored in the memory as Vactp as per Equation (25) below. Next, Steps S 175   b , S 175   c  and S 175   d  are executed.
 
 V act= V act p+dV act  (24)
 
Vactp=Vact  (25)
 
     In Step S 175   b , the actuator is operated. In Step S 175   c , shooting is executed. In Step S 175   d , the contrast evaluation value for automatic focusing control is created. The operations similar to those in Step  172   b , Step S 172   c  and Step S 172   d  are carried out. The contrast evaluation value C 5  is given as a contrast evaluation value for automatic focusing after positive correction C 5   p  as per Equation (26) below and written into the memory in the system control portion  131 . Next, Step S 175   e  is executed.
 
C5p=C5  (26)
 
     In Step S 175   e , the contrast evaluation values for focusing control are evaluated. C 5   pp  and C 5   p  are compared, and the operation is branched according to which has the maximum value. 
     When C 5   pp  is the maximum value, the following operation is carried out, and then Step S 181  is executed.  FIG. 17A  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value before the further positive correction is at a maximum in the case where this further positive correction is performed in the camera module according to Embodiment 1 of the present invention. As shown in  FIG. 17A , the actuator operation amount after the previous positive correction Vactp−dVact gives substantially the maximum value of the contrast value for automatic focusing control C 5 . Therefore, as in Equation (27) below, Vactp−dVact serves as the final actuator operation amount Vactf.
 
 V act f=V act p−dV act(when C5 pp  is the maximum value)  (27)
 
     When C 5   p  is the maximum value, the following operation is carried out, and then Step S 175   a  is executed.  FIG. 17B  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value after the further positive correction is at a maximum in the case where this further positive correction is performed in the camera module according to Embodiment 1 of the present invention. As shown in  FIG. 17B , the actuator operation amount after the current positive correction Vactp or the actuator operation amount after a further positive correction Vact gives substantially the maximum value of the contrast evaluation value for automatic focusing control C 5 . Therefore, the actuator operation amount is corrected further toward the positive side, and a search is made for the maximum value. Incidentally, as in Equation (28) below, C 5   p  serves as a previous value and is stored as C 5   pp.  
 
C5pp=C5p  (28)
 
     In Step S 176 , the contrast evaluation value for automatic focusing at the time of the further negative correction is created and evaluated. Step S 176  includes Step S 176   a , Step S 176   b , Step S 176   c , Step S 176   d  and Step S 176   e . First, Step S 176   a  is executed. 
     In Step S 176   a , an actuator operation amount at the time of negative correction Vact is obtained by subtracting dVact from the actuator operation amount (the voltage to be applied to the coil of the actuator fixing portion  114 ) after the previous negative correction Vactn as per Equation (29) below and stored in the memory as Vactn as per Equation (30) below. Next, Steps S 176   b , S 176   c  and S 176   d  are executed.
 
 V act= V act n−dV act  (29)
 
Vactn=Vact  (30)
 
     In Step S 176   b , the actuator is operated. In Step S 176   c , shooting is executed. In Step S 176   d , the contrast evaluation value for automatic focusing control is created. The operations similar to those in Step  172   b , Step S 172   c  and Step S 172   d  are carried out. The contrast evaluation value C 5  is given as a contrast evaluation value for automatic focusing after negative correction C 5   n  as per Equation (31) below and written into the memory in the system control portion  131 . Next, Step S 176   e  is executed.
 
C5n=C5  (31)
 
     In Step S 176   e , the contrast evaluation values for focusing control are evaluated. C 5   np  and C 5   n  are compared, and the operation is branched according to which has the maximum value. 
     When C 5   np  is the maximum value, the following operation is carried out, and then Step S 181  is executed.  FIG. 18A  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value before the further negative correction is at a maximum in the case where this further negative correction is performed in the camera module according to Embodiment 1 of the present invention. As shown in  FIG. 18A , the actuator operation amount after the previous negative correction Vactn+dVact gives substantially the maximum value of the contrast value for automatic focusing control C 5 . Therefore, as in Equation (32) below, Vactn+dVact serves as the final actuator operation amount Vactf
 
 V act f=V act n+dV act(when C5 np  is the maximum value)  (32)
 
     When C 5   n  is the maximum value, the following operation is carried out, and then Step S 176   a  is executed.  FIG. 18B  is a drawing for describing the relationship between the actuator operation amount and the contrast evaluation value when the contrast evaluation value after the further negative correction is at a maximum in the case where this further negative correction is performed in the camera module according to Embodiment 1 of the present invention. As shown in  FIG. 18B , the actuator operation amount after the current negative correction Vactn or the actuator operation amount after a further negative correction Vact gives substantially the maximum value of the contrast evaluation value for automatic focusing control C 5 . Therefore, the actuator operation amount is corrected further toward the negative side, and a search is made for the maximum value. Incidentally, as in Equation (33) below, C 5   n  serves as a previous value and is stored as C 5   np.  
 
C5np=C5n  (33)
 
     In Steps S 181 , S 182 , S 183 , S 184  and S 185 , a final shooting and an image output are performed. 
     In Step S 181 , as in Equation (34) below, the final actuator operation amount Vactf obtained above is set as the actuator operation amount Vact. Next, Step S 182  is executed.
 
Vact=Vactf  (34)
 
     In S 182 , the actuator is operated. The operation in this step is similar to that in Step S 164 . Next, Step S 183  is executed. 
     In Step S 183 , shooting is performed. The operation in this step is similar to that in Step S 110 . Next, Step S 184  is executed. 
     In Step S 184 , a parallax correction is carried out for each block using the parallax value corresponding to this block, and then an image synthesis is performed. The operation in this step is similar to that in Step S 151 . Next, Step S 185  is executed. 
     In Step S 185 , an image is outputted. The operation in this step is similar to that in S 152 . Next, Step S 190  is executed. 
     In Step S 190 , the actuator operation amount function correcting portion  149  corrects an operation amount function based on a correction value for a contrast-based automatic focusing control. In other words, a coefficient kb of the operation amount function is corrected as per Equation (35) below so as to change a value written in the memory in the system control portion  131 . This value is used at the time of the next shooting. Next, Step S 199  is executed.
 
 kb=kb+kc ·( V act f−V act0)  (35)
 
     In Step S 199 , the processing ends. 
     With the above-described configuration and operations, the following effects are achieved. 
     In the camera module according to Embodiment 1, as in Steps S 161 , S 162 , S 163  and S 164 , the actuator positional instruction Xact is created based on the parallax value Δaf for automatic focusing control, the actuator operation amount Vact is computed, and a voltage is applied to the coil of the actuator fixing portion  114  so as to operate the actuator, thereby carrying out the automatic focusing control. In this manner, a focus is achieved by a single actuator operation, thus allowing a high-speed automatic focusing control. 
     Also, in the camera module according to Embodiment 1, first, in Steps S 161 , S 162 , S 163  and S 164 , the actuator is operated based on the parallax so as to carry out the automatic focusing control. Subsequently, in Steps S 171 , S 172 , S 173 , S 174 , S 175  and S 176 , the actuator is operated based on the contrast so as to carry out the automatic focusing control. The automatic focusing control based on the parallax is performed at a high speed, because the focus is achieved by a single actuator operation. On the other hand, the automatic focusing control based on the contrast is not susceptible to variations of the actuator and thus is highly accurate, because the focus achievement is judged directly from the image. Consequently, since a coarse adjustment is made by the high-speed automatic focusing control based on the parallax and a fine adjustment is made by the highly-accurate automatic focusing control based on the contrast, it is possible to achieve a high-speed and highly-accurate automatic focusing control. 
     Further, in the camera module according to Embodiment 1, in Step S 190 , learning is conducted so as to correct the coefficient kb of the operation amount function based on the actuator operation amount (Vactf−Vact 0 ) corrected in the contrast-based automatic focusing control. This makes it possible to correct the operation amount function in a more accurate manner even when there are variations in the actuator, achieve a more accurate parallax-based automatic focusing control and reduce the number of the next fine adjustments by the contrast-based automatic focusing control, so that a higher-speed automatic focusing control can be achieved. 
     As in Equation (1), the relative positions of the four object images formed respectively by the first lens portion  113   a , the second lens portion  113   b , the third lens portion  113   c  and the fourth lens portion  113   d  vary according to the subject distance A. In other words, when the subject distance A decreases, the parallax Δ increases. Accordingly, when a plurality of subjects at different distances are shot at the same time, the parallaxes A for the individual subjects are different. In the camera module according to Embodiment 1, the entire image region is divided into blocks in Step S 130 , the parallax for each block is computed in Step S 140 , and the parallax correction is carried out by the image synthesis based on the parallax for each block so as to reduce the parallactic influence in Step S 184 . In this manner, even when a plurality of subjects at different distances are shot at the same time, it is possible to correct the parallaxes of the individual subjects suitably, thereby achieving a beautiful image with reduced parallactic influence over the entire image region. 
     Moreover, in the camera module according to Embodiment 1, the edges are detected in Steps S 121  and S 122 , and the division into blocks is carried out in Step S 130 . This allows a suitable division into blocks, making it possible to achieve a beautiful image with reduced parallactic influence over the entire image region. 
     Incidentally, although the computed parallaxes are used as they are in the camera module according to Embodiment 1, they also may be limited suitably. Depending on the lens characteristics, the image becomes unclear when the subject distance A is smaller than a certain value. Accordingly, by setting this value as the minimum value of the subject distance A, the maximum value of the parallax Δ can be determined. A parallax larger than this value may be ignored as being an error. Also, in this case, a value with the second smallest parallax evaluation value may be adopted as the parallax. 
     Furthermore, in the camera module according to Embodiment 1, the parallax is computed from the first imaging signal I 1  (mainly indicating green) and the fourth imaging signal I 4  (mainly indicating green). However, the present invention is not limited to this. For example, in the case where a violet subject contains a smaller green component and larger blue and red components and thus the computation from the first imaging signal I 1  (mainly indicating green) and the fourth imaging signal I 4  (mainly indicating green) is not possible, the parallax also may be computed from the second imaging signal I 2  (mainly indicating blue) and the third imaging signal I 3  (mainly indicating red). Further, if the parallax cannot be computed from the first imaging signal I 1  (mainly indicating green) and the fourth imaging signal I 4  (mainly indicating green) and the parallax cannot be computed from the second imaging signal I 2  (mainly indicating blue) and the third imaging signal I 3  (mainly indicating red), it is appropriate to consider that no parallactic influence is present and there is no parallax. 
     Also, when the camera module according to Embodiment 1 is mounted on a camera, the first to fourth imaging devices  123   a  to  123   d  are arranged so that the second imaging device  123   b  is located on an upper side and the third imaging device  123   c  is located on a lower side, whereby the upper side is sensitive to blue and the lower side is sensitive to red. Consequently, it is possible to achieve a more natural color reproduction for landscape photographs. 
     Further, when the parallax evaluation value has two prominent maximum values, the parallax for the larger may be adopted. Two maximum values appear because such a block contains a subject and a background and the subject distance and the background distance are different. Since the subject distance is smaller than the background distance, the parallax of the subject is larger than that of the background. Here, by adopting the larger parallax, the parallactic influence of the subject, which affects an image quality directly, can be reduced, though the parallactic influence of the background cannot be reduced. 
     Also, the timing of the image output is not limited to the above, and a preview may be outputted suitably. For example, after shooting in Step S 110 , an image without parallax correction may be outputted. Further, in the block division in Step S 130 , when one block is divided, the result thereof may be reflected to update a preview screen. 
     Moreover, the camera module according to Embodiment 1 operates the actuator based on the parallax in S 164  and then operates the actuator based on the contrast in S 171 , S 172 , S 173 , S 175  and S 182 . However, the actuator may be operated only based on the parallax. The reason is that, in the case of using a lens with a large depth of focus, a slight error in the distance between the lens and the imaging device can be tolerated, and thus there is no need to operate the actuator based on the contrast so as to improve the accuracy. 
     Further, although the camera module according to Embodiment 1 corrects the correction amount function in S 190 , namely, conducts learning based on the operation amount at the time of operating the actuator based on the contrast, this step also may be omitted. Since the actuator of the camera module according to Embodiment 1 is of a voice coil type, the movement amount of the lens varies with changes in temperature and orientation, so that the accuracy improves considerably by learning. However, in the case of using a stepping motor, since the movement amount of the lens does not vary very much with changes in temperature and orientation, the learning may be omitted. 
     Moreover, there may be some cases where the focusing control by the parallax is performed but the actuator is not operated. For example, the relative distance between the lens and the imaging device is set in advance to the distance at which the focus is achieved at the time of shooting an infinity object. Then, when the parallax is small, it may be considered unnecessary to operate the actuator, thus choosing not to operate the actuator. 
     Furthermore, it also may be possible to add an operation of repeating the block division and updating the blocks suitably. For example, in Embodiment 1, after shooting in S 183 , it may be possible to update the blocks by conducting S 121 , S 122  and S 130  and then perform the parallax correction in Step S 184 . 
     Embodiment 2 
     A camera module according to Embodiment 2 of the present invention achieves a beautiful image with a reduced parallactic influence over an entire image region by detecting a parallax of an edge using contrasts of a plurality of images, computing a parallax of the entire image region based on that parallax, performing an image synthesis so as to reduce a parallactic influence based on this parallax and performing a parallax correction. 
     The camera module according to Embodiment 2 of the present invention will be described, with reference to the accompanying drawings. 
       FIG. 19  is a sectional view showing a configuration of the camera module according to Embodiment 2 of the present invention. The configuration is similar to that of Embodiment 1 except for an SLSI  225  of a circuit portion  220  of a camera module  201 . Members similar to those in Embodiment 1 are assigned the same reference numerals, and the description thereof will be omitted. 
       FIG. 20  is a block diagram showing the camera module according to Embodiment 2 of the present invention. The SLSI  225  includes a system control portion  231 , an imaging device driving portion  132 , an imaging signal input portion  133 , an actuator operation amount output portion  134 , an image processing portion  235  and an input/output portion  136 . Also, the circuit portion  220  includes an amplifier  126  in addition to the configuration described above. 
     The system control portion  231  is configured by a CPU, a memory, etc. and controls the entire SLSI  225 . 
     The image processing portion  235  is configured so as to include a logic circuit, a DSP or both of the logic circuit and the DSP and carries out various image processings utilizing memory information in the system control portion  231 . The image processing portion  235  includes a contrast computing portion  241 , an automatic focusing control portion  242 , an edge parallax computing portion  243 , an entire image region parallax computing portion  244  and a parallax correcting portion  245 . 
     The imaging device driving portion  132 , the imaging signal input portion  133 , the actuator operation amount output portion  134 , the input/output portion  136  and the amplifier  126  are similar to those in Embodiment 1, and the description thereof will be omitted. 
       FIG. 21  is a flowchart showing an operation of the camera module according to Embodiment 2 of the present invention. The camera module  201  is operated as per this flowchart by the system control portion  231  of the SLSI  225 . 
     In Step S 200 , the operation starts. For example, the main CPU (not shown) senses that a shutter button or the like is pressed down, and instructs the camera module to start operating via the input/output portion  136 , whereby the camera module  201  starts operating. Next, Step S 211  is executed. 
     In Steps S 211 , S 212 , S 213 , S 214 , S 215 , S 216  and S 217 , shooting is conducted plural times, contrast evaluation values are computed, and imaging signals and the contrast evaluation values are stored. 
     In Step S 211 , a counter i is initialized as in Equation (36) below. Next, Step S 212  is executed.
 
i=0  (36)
 
     In Step S 212 , an actuator positional instruction Xact is created. Incidentally, the positional instruction Xact indicates an instruction of a position in a direction toward the subject with respect to the position at which an infinity object is focused. Next, Step S 213  is executed.
 
 X act= kx 2· i   (37)
 
     In Step S 213 , an actuator control amount Vact is computed using a control amount function based on the actuator positional instruction Xact as per Equation (38) below. Next, Step S 214  is executed.
 
 V act= ka·X act+ kb   (38)
 
     In Step S 214 , an actuator is operated. This operation is similar to that in Step S 164  in Embodiment 1, and the description thereof will be omitted. Next, Step S 215  is executed. 
     In Step S 215 , shooting is conducted, and an imaging signal is stored. On the instruction of the system control portion  231 , the imaging device driving portion  132  outputs signals for an electronic shutter and transferring as necessary. The first imaging signal input portion  133   a , the second imaging signal input portion  133   b , the third imaging signal input portion  133   c  and the fourth imaging signal input portion  133   d  input imaging signals, which are analog signals of the images outputted respectively by the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d , in synchronization with the signals generated by the imaging device driving portion  132 , remove fixed noises with the CDS, adjust input gains automatically with the AGC, convert the analog signals into digital values with the ADC, and write the digital values into the memory at a predetermined address in the system control portion  231  as a first imaging signal I 1 ( i,x,y ), a second imaging signal I 2 ( i,x,y ), a third imaging signal I 3 ( i,x,y ) and a fourth imaging signal I 4 ( i,x,y ).  FIG. 22  is a drawing for describing coordinates of the imaging signal of the camera module according to Embodiment 2 of the present invention. I 4 ( i,x,y ) indicates the first imaging signal of the i-th shot, which is the x-th signal in a horizontal direction and the y-th signal in a vertical direction. In an image to be inputted, the number of pixels in the vertical direction is H, the number of pixels in the horizontal direction is L, and the total number of pixels is H×L. x varies from 0 to L−1, and y varies from 0 to H−1. Further, i is the counter indicating that it is an image of the “i+1”-th shot. This also holds true for the second imaging signal I 2 ( i,x,y ), the third imaging signal I 3 ( i,x,y ) and the fourth imaging signal I 4 ( i,x,y ). In other words, I 2 ( i,x,y ), I 3 ( i,x,y ) and I 4 ( i,x,y ) respectively indicate the second imaging signal, the third imaging signal and the fourth imaging signal of the “i+1”-th shot, each of which is the x-th signal in the horizontal direction and the y-th signal in the vertical direction. In an image to be inputted, the number of pixels in the vertical direction is H, the number of pixels in the horizontal direction is L, and the total number of pixels is H×L. x varies from 0 to L−1, and y varies from 0 to H−1. Further, i is the counter indicating that it is an image of the “i+1”-th shot. Next, Step S 216  is executed. 
     In Step S 216 , the contrast computing portion  241  computes and stores a contrast evaluation value using data in the memory in the system control portion  231 . This computation is performed only for the first imaging signal I 1 . Laplacian is computed as per Equation (39) below and further is subjected spatially to a LPF (low-pass filter) as per Equation (40) below, and the result is given as a contrast evaluation value C 2 ( i,x,y ). Then, this is written into the memory in the system control portion  231 . Next, Step S 217  is executed. 
     
       
         
           
             
               
                 
                   
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     In Step S 217 , the number of shots is checked, and the operation is branched. First, as in Equation (41) below, the counter i is increased by 1. If the counter i is smaller than the number of shots Np, then Step S 212  is executed. If the counter i is equal to the number of shots Np, then Step S 221  is executed.
 
 i=i+ 1  (41)
 
     In Step S 221  and Step S 222 , the automatic focusing control portion  242  selects an image shot at a position where the focus is achieved by using data in the memory in the system control portion  231 . 
     In Step S 221 , a block for automatic focusing is created. A rectangular block near the center of the image region serves as the block for automatic focusing. Incidentally, this block does not have to be the one near the center but may be the one created by reflecting an intention of a user operating the camera (for example, by detecting a viewpoint direction with a sensor). Next, Step S 222  is executed. 
     In Step S 222 , the image shot at the position where the focus is achieved is selected. As described referring to  FIG. 9 , the image shot at the position where the focus is achieved has the maximum contrast. Using this principle, the image shot at the position where the focus is achieved is selected. First, as in Equation (42) below, an average of the contrast evaluation values C 2 ( i,x,y ) for the individual shots in the block for automatic focusing serves as a contrast evaluation value for automatic focusing control C 3 . Incidentally, Σ represents a sum in the blocks for automatic focusing. Subsequently, i giving the maximum value of C 3 ( i ) is used as a focus achievement counter value ip, so that an image at the position where the focus is achieved is determined. Next, Step S 230  is executed.
 
 C 3( i )=|Σ C 2( i,x,y )|/ N   (42)
 
ip: i giving the maximum value of C3(i)  (43)
 
     In Step S 230 , the edge parallax computing portion  243  detects an edge using the data in the memory in the system control portion  231  and detects its parallax. Similarly to Step S 122  in Embodiment 1, a zero crossing (a point at which a value changes from positive to negative and a point at which a value changes from negative to positive) of the contrast evaluation value C 2 ( ie,x,y ) is sensed utilizing the image at the position where the focus is achieved. 
     Next, with respect to a point (xe,ye) on the edge, a rectangular block whose center is at (xe,ye) is set, and the sum of absolute values of the contrast evaluation values C 2 ( i,x,y ) for all the shot images is given as C 4 ( i,xe,ye ) as in Equation (44) below. Here, Σ represents the sum in the set rectangular block. Then, based on the principle described referring to  FIG. 9 , ipe(xe,ye) indicating the position where the focus is achieved at (xe,ye) on the edge serves as i giving the maximum value of C 4 ( i,xe,ye ) as in Equation (45) below. Here, utilizing Equation (9) and Equation (37), the parallax Δ(xe,ye) at the point (xe,ye) on the edge is expressed by Equation (46) below. Next, Step S 240  is executed.
 
 C 4( i,xe,ye )=Σ| C 2( i,x,y )|  (44)
 
ipe(xe,ye): i giving the maximum value of C4(i,xe,ye)  (45)
 
Δ( xe,ye )=( kx 2 /kx ) ipe ( xe,ye )  (46)
 
     In Step S 240 , the entire image region parallax computing portion  244  computes the parallax Δ(x,y) in the entire image region from the parallax Δ(xe,ye) at the point (xe,ye) on the edge using the data in the memory in the system control portion  231 . This parallax Δ(xe,ye) on the edge is adopted as a parallax Δ(x,y) of a region surrounded by substantially the same parallaxes Δ(xe,ye) on the edge. Next, Step S 250  is executed. 
     In Step S 250 , the parallax correcting portion  245  utilizes data in the memory in the system control portion  231 , carries out a parallax correction using the parallax Δ(x,y) in the entire region, and then performs an image synthesis. Then, the parallax correcting portion  245  writes the result into the memory in the system control portion  231 . Since the first imaging device  123   a  and the fourth imaging device  123   d  mainly receive the green component of the object light, the first imaging signal I 1  and the fourth imaging signal I 4  are information signals of the green component of the object light. Also, since the second imaging signal  123   b  mainly receives the blue component of the object light, the second imaging signal I 2  is an information signal of the blue component of the object light. Further, since the third imaging signal  123   c  mainly receives the red component of the object light, the third imaging signal I 3  is an information signal of the red component of the object light. Since the parallax between the first imaging device  123   a  and the fourth imaging device  123   d  at (x,y) is calculated to be (Δ(x,y), Δ(x,y)), G(x,y) indicating the intensity of green at (x,y) is given by an average of the first imaging signal I 1 (ip,x,y) and the fourth imaging signal I 4 (ip,x−Δ(x,y),y−Δ(x,y)) as in Equation (47) below. Also, since the parallax between the first imaging device  123   a  and the second imaging device  123   b  at (x,y) is calculated to be (Δ(x,y), 0), B(x,y) indicating the intensity of blue at (x,y) is given by the second imaging signal I 2 (ip,x−Δ(x,y),y) as in Equation (48) below. Further, since the parallax between the first imaging device  123   a  and the third imaging device  123   c  at (x,y) is calculated to be (0,Δ(x,y)), R(x,y) indicating the intensity of red at (x,y) is given by the third imaging signal I 3 (ip,x,y−Δ(x,y)) as in Equation (49) below. Next, Step S 260  is executed.
 
 G ( x,y )=[ I 1( ip,x,y )+ I 4( ip,x −Δ( x,y ), y −Δ( x,y ))]/2  (47)
 
 B ( x,y )= I 2( ip,x −Δ( x,y ), y )  (48)
 
 R ( x,y )= I 3( ip,x,y −Δ( x,y ))  (49)
 
     In Step S 260 , an image is outputted. The operation in this step is similar to that in S 152  in Embodiment 1. Next, Step S 299  is executed. 
     In Step S 299 , the processing ends. 
     With the above-described configuration and operations, the following effects are achieved. 
     The parallax of the edge is detected using the contrasts of a plurality of images, the parallax of the entire image region is computed based on this parallax, and the image synthesis is performed based on this parallax so as to reduce the parallactic influence, thereby performing the parallax correction. This makes it possible to achieve a beautiful image with a reduced parallactic influence over the entire image region. 
     Incidentally, although the parallax of the edge is obtained using the contrast evaluation values of plural shots in the camera module according to Embodiment 2, the present invention is not limited to this. For example, it also may be appropriate to set a block whose center is at a point on the edge to be calculated, compute a parallax of this block by the method used in Embodiment 1 and adopt this parallax. Also, several points on the edge may be combined to form a line instead of a point for computing the parallax. Further, a linear edge may be divided at end points or branch points into a plurality of line segments so as to compute parallaxes thereof. Also, a block including the periphery of this line segment may be created so as to compute a parallax of this block by the method used in Embodiment 1. Moreover, the parallax obtained from the contrast evaluation value and the parallax obtained by the method used in Embodiment 1 may be combined. For example, it may be appropriate to use an average parallax or learn a coefficient of the actuator operation amount function. 
     In addition, although the division into blocks is carried out according to the edge information in Embodiment 1 and Embodiment 2, the present invention is not limited to this. For example, the unit of division may be a rectangular block. 
     Embodiment 3 
     A camera module according to Embodiment 3 of the present invention divides an imaging region into blocks, computes a parallax for each block and evaluates the parallax based on a contrast value computed for each block and a correlation of an image shifted by the parallax. When the correlation is high and the contrast is high, the computed parallax is judged to be appropriate, and a usual parallax correction is performed based on the parallax. When the correlation is low and the contrast is low, the computed parallax is judged not to be accurate, and a parallax correction for low contrast is performed. Further, when the correlation is low and the contrast is high, it is judged that the computed parallax is not appropriate because subjects at plural distances are contained, and the blocks are re-divided. In this way, a beautiful image over an entire image region is obtained. 
     In the following, the camera module according to Embodiment 3 of the present invention will be described, with reference to the accompanying drawings. 
       FIG. 23  is a sectional view showing a configuration of the camera module according to Embodiment 3 of the present invention. The configuration is similar to that of Embodiment 1 except for an SLSI  325  of a circuit portion  320  of a camera module  301 . Members similar to those in Embodiment 1 are assigned the same reference numerals, and the description thereof will be omitted. 
       FIG. 24  is a block diagram showing the camera module according to Embodiment 3 of the present invention. The SLSI  325  includes a system control portion  331 , an imaging device driving portion  132 , an imaging signal input portion  133 , an actuator operation amount output portion  134 , an image processing portion  335  and an input/output portion  136 . Also, the circuit portion  320  includes an amplifier  126  in addition to the configuration described above. 
     The image processing portion  335  is configured so as to include a logic circuit, a DSP (digital signal processor) or both of the logic circuit and the DSP and carries out various image processings utilizing memory information in the system control portion  331 . The image processing portion  335  includes an automatic focusing control portion  341 , a block division portion  342 , a parallax computing portion  343 , a correlation computing portion  344 , a contrast computing portion  345 , a block re-dividing portion  346 , a usual parallax correcting portion  347 , a parallax correcting portion for low contrast  348  and a parallax correcting portion for low correlation  349 . 
       FIG. 25  is a flowchart showing the operation of the camera module according to Embodiment 3 of the present invention. The camera module  301  is operated as per this flowchart by the system control portion  331  of the SLSI  325 . 
     In Step S 3000 , the operation starts. For example, the main CPU (not shown) senses that a shutter button (not shown) or the like is pressed down, and instructs the camera module  301  to start operating via the input/output portion  136 , whereby the camera module  301  starts operating. Next, Step S 3100  is executed. 
     In Step S 3100 , the automatic focusing control portion  341  executes an automatic focusing control.  FIG. 26  is a flowchart showing an operation of the automatic focusing control according to Embodiment 3 of the present invention. The flowchart of  FIG. 26  shows the operation in Step S 3100  in detail. 
     In the automatic focusing control in Step S 3100 , Step S 3121  is executed first. 
     In Step S 3121 , a counter i is initialized to 0. Next, Step S 3122  is executed. 
     In Step S 3122 , an actuator positional instruction is computed. As per Equation (50) below, an actuator positional instruction Xact is computed using the counter i. Incidentally, the positional instruction Xact indicates an instruction of a position at which a direction toward the subject is positive with respect to the position at which an infinity object is focused. Here, kx is a set value. Next, Step S 3123  is executed.
 
 X act= kx·i   (50)
 
     In Step S 3123 , an actuator operation amount (a voltage to be applied to the coil of the actuator movable portion  115 ) Vact is computed using an operation amount function expressed by Equation (51) below. Here, ka and kb respectively are set values. Next, Step S 3124  is executed.
 
 V act= ka·X act+ kb   (51)
 
     In Step S 3124 , an actuator is operated. The actuator operation amount output portion  134  changes a voltage signal to be outputted so that the voltage to be applied to the coil (not shown) of the actuator movable portion  115  via the amplifier  126  is Vact. Next, Step S 3125  is executed. 
     In Step S 3125 , shooting is executed. On the instruction of the system control portion  331 , the imaging device driving portion  132  outputs signals for an electronic shutter and transferring as necessary. The first imaging signal input portion  133   a , the second imaging signal input portion  133   b , the third imaging signal input portion  133   c  and the fourth imaging signal input portion  133   d  input imaging signals, which are analog signals of the images outputted respectively by the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d , in synchronization with the signals generated by the imaging device driving portion  132 , remove fixed noises with the CDS, adjust input gains automatically with the AGC, convert the analog signals into digital values with the ADC, and write the digital values into the memory at a predetermined address in the system control portion  331  as a first imaging signal I 1 ( x,y ), a second imaging signal I 2 ( x,y ), a third imaging signal I 3 ( x,y ) and a fourth imaging signal I 4 ( x,y ).  FIG. 12  is a drawing for describing coordinates of the imaging signal of the camera module according to Embodiment 1 of the present invention. I 1 ( x,y ) indicates the first imaging signal, which is the x-th signal in a horizontal direction and the y-th signal in a vertical direction. In an image to be inputted, the number of pixels in the vertical direction is H, the number of pixels in the horizontal direction is L, and the total number of pixels is H×L. x varies from 0 to L−1, and y varies from 0 to H−1. This also holds true for the second imaging signal I 2 ( x,y ), the third imaging signal I 3 ( x,y ) and the fourth imaging signal I 4 ( x,y ). In other words, I 2 ( x,y ), I 3 ( x,y ) and I 4 ( x,y ) respectively indicate the second imaging signal, the third imaging signal and the fourth imaging signal, each of which is the x-th signal in the horizontal direction and the y-th signal in the vertical direction. In an image to be inputted, the number of pixels in the vertical direction is H, the number of pixels in the horizontal direction is L, and the total number of pixels is H×L. x varies from 0 to L−1, and y varies from 0 to H−1. Next, Step S 3126  is executed. 
     In Step S 3126 , a block for automatic focusing control is set. A rectangular region near the center of the image region serves as the block for automatic focusing control. Incidentally, this block does not have to be the one near the center but may be the one set by reflecting an intention of a user operating the camera (for example, by detecting a viewpoint direction with a sensor). Incidentally, it also may be possible to select plural blocks instead of a single block and use an average of contrast evaluation values for automatic focusing control described later in these plural blocks. Alternatively, it also may be possible to compute contrast evaluation values for automatic focusing control described later in plural blocks and select at least one block thereafter as a block for automatic focusing control. Next, Step S 3127  is executed. 
     In Step S 3127 , the contrast value for automatic focusing control is created using the data in the memory in the system control portion  331 . This computation is performed for pixels in the block for automatic focusing control of the first imaging signal I 1 . An absolute value of Laplacian, which is a sum of second order differentials in the x and y directions, is computed as per Equation (52) below and further is subjected spatially to a LPF (low-pass filter) as per Equation (53) below, and the result is averaged in the block for automatic focusing control as per Equation (54) below, thereby obtaining a contrast evaluation value for automatic focusing C 3 . Here, Naf represents the number of pixels in the block for automatic focusing control. Next, Step S 3128  is executed. 
     
       
         
           
             
               
                 
                   
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     In Step S 3128 , the contrast evaluation value C 3  is given as C 3 ( i ) as in Equation (55) below and written into the memory in the system control portion  331 . Next, Step S 3129  is executed.
 
 C 3( i )= C 3  (55)
 
     In Step S 3129 , 1 is added to the counter i as per Equation (56) below. Next, Step S 3130  is executed.
 
 i=i+ 1  (56)
 
     In Step S 3130 , the counter i is compared with a threshold Saf, and the operation is branched according to the result. When the counter i is smaller than the threshold Saf (the result of comparison in Step S 3130  is Y), then Step S 3122  is executed. On the other hand, when the counter i is equal to or larger than the threshold Saf (the result of comparison in Step S 3130  is N), then Step S 3140  is executed. In this manner, by initializing the counter i to 0 in Step S 3121 , adding 1 to the counter i in Step S 3129  and branching the operation according to the counter i in Step S 3130 , the processings from S 3122  to S 3128  are repeated Saf times. 
     In Step S 3140 , the contrast evaluation value C 3  is evaluated. As illustrated in  FIG. 9 , the contrast evaluation value C 3  becomes maximum at the position where the focus is achieved. As in Equation (57) below, the counter value i giving this maximum value is given as a counter value iaf giving the contrast maximum value. Next, Step S 3151  is executed.
 
iaf=i giving the maximum value of C3  (57)
 
     In Step S 3151 , an actuator positional instruction is computed. As per Equation (58) below, an actuator positional instruction Xact is computed using the counter value iaf giving the contrast maximum value. Incidentally, the positional instruction Xact indicates an instruction of a position at which a direction toward the subject is positive with respect to the position at which an infinity object is focused. Next, Step S 3152  is executed.
 
 X act= kx·iaf   (58)
 
     In Step S 3152 , an actuator operation amount (a voltage to be applied to the coil of the actuator movable portion  115 ) Vact is computed using an operation amount function. This operation is similar to that in Step S 3123 , and the description thereof will be omitted. Next, Step S 3153  is executed. 
     In Step S 3153 , an actuator is operated. This operation is similar to that in Step S 3124 , and the description thereof will be omitted. Next, Step S 3160  is executed. 
     In Step S 3160 , the automatic focusing control is ended, thus returning to a main routine. Accordingly, Step S 3200  in  FIG. 25  is executed next. 
     In Step S 3200 , the parallax correction is executed.  FIG. 27  is a flowchart showing an operation of the parallax correction according to Embodiment 3 of the present invention. The flowchart of  FIG. 27  shows the operation in Step S 3200  in detail. 
     In the parallax correction in Step S 3200 , Step S 3220  is executed first. 
     In Step S 3220 , shooting is executed. On the instruction of the system control portion  331 , the imaging device driving portion  132  outputs signals for an electronic shutter and transferring as necessary. The first imaging signal input portion  133   a , the second imaging signal input portion  133   b , the third imaging signal input portion  133   c  and the fourth imaging signal input portion  133   d  input imaging signals, which are analog signals of the images outputted respectively by the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d , in synchronization with the signals generated by the imaging device driving portion  132 , remove fixed noises with the CDS, adjust input gains automatically with the AGC, convert the analog signals into digital values with the ADC, and write the digital values into the memory at a predetermined address in the system control portion  331  as a first imaging signal I 1 ( x,y ), a second imaging signal I 2 ( x,y ), a third imaging signal I 3 ( x,y ) and a fourth imaging signal I 4 ( x,y ).  FIG. 12  is a drawing for describing coordinates of the imaging signal of the camera module according to Embodiment 1 of the present invention. I 1 ( x,y ) indicates the first imaging signal, which is the x-th signal in a horizontal direction and the y-th signal in a vertical direction. In an image to be inputted, the number of pixels in the vertical direction is H, the number of pixels in the horizontal direction is L, and the total number of pixels is H×L. x varies from 0 to L−1, and y varies from 0 to H−1. This also holds true for the second imaging signal I 2 ( x,y ), the third imaging signal I 3 ( x,y ) and the fourth imaging signal I 4 ( x,y ). In other words, I 2 ( x,y ), I 3 ( x,y ) and I 4 ( x,y ) respectively indicate the second imaging signal, the third imaging signal and the fourth imaging signal, each of which is the x-th signal in the horizontal direction and the y-th signal in the vertical direction. In an image to be inputted, the number of pixels in the vertical direction is H, the number of pixels in the horizontal direction is L, and the total number of pixels is H×L. x varies from 0 to L−1, and y varies from 0 to H−1. Next, Step S 3230  is executed. 
     In Step S 3230 , the block division portion  342  utilizes data in the memory in the system control portion  331  and carries out a division into blocks. Then, the block division portion  342  writes the result into the memory in the system control portion  331 .  FIG. 28  is a drawing for describing the block division in the camera module according to Embodiment 3 of the present invention. As shown in  FIG. 28 , the first imaging signal I 1  is divided into M blocks in the horizontal direction and N blocks in the vertical direction, namely, M×N blocks in total, and each block is expressed by Bi. Here, i varies from 0 to M×N−1. Next, Step S 3240  is executed. 
     In Step S 3240 , the parallax computing portion  343  utilizes data in the memory in the system control portion  331  and computes a parallax value for each block. Then, the parallax computing portion  343  writes it into the memory in the system control portion  331 . First, for each block (B 0 , B 1 , Bi, . . . , BMN−1), a parallax evaluation value (R 0 ( k ), R 1 ( k ), . . . , Ri(k), . . . , RMN−1(k); k=0, 1, . . . , kmax) is computed.  FIG. 29  is a drawing for describing computation regions of the parallax evaluation value in the camera module according to Embodiment 3 of the present invention. A region indicated by Bi (also indicated by I 1 ) is the i-th block obtained from the first imaging signal I 1  in Step S 3230 . A region indicated by I 4  is a region obtained by moving from Bi by k in the x direction and k in the y direction. Then, for all image signals I 1 ( x,y ) and I 4 ( x −k,y−k) in these regions, the sum of absolute difference expressed by Equation (59) below is computed as a parallax evaluation value Ri(k).
 
 Ri ( k )=ΣΣ| I 1( x,y )− I 4( x−k,y−k )|  (59)
 
     This parallax evaluation value Ri(k) indicates how much the first image signal I 1  of the i-th block Bi and the fourth image signal I 4  in the region shifted therefrom by (k, k) respectively in the x and y directions are correlated. The smaller the parallax evaluation value Ri(k) is, the higher the correlation is (the higher the degree of similarity is). As shown in  FIG. 15 , the parallax evaluation value Ri(k) varies with the value of k and is at a minimum when k=Δi. This indicates that the image signal obtained by moving the i-th block Bi of the fourth image signal I 4  by (−Δi, −Δi) respectively in the x and y directions has the highest correlation with (the highest degree of similarity to) the first image signal I 1 . Accordingly, it is understood that the parallax in the x and y directions between the first imaging signal I 1  and the fourth imaging signal I 4  for the i-th block Bi is (Δi, Δi). In the following, this Δ(i,j) is referred to as a parallax value Δ(i,j) of the i-th block B(i,j). In this manner, the parallax values Δi of Bi from i=0 to i=M×N−1 are obtained. Next, Step S 3251  is executed. 
     In Step S 3251 , the correlation computing portion  344  computes a correlation value for parallax accuracy evaluation for each block utilizing the data in the memory in the system control portion  331 . Then, the correlation computing portion  344  writes the result into the memory in the system control portion  331 .  FIG. 30  is a drawing for describing computation regions of the correlation value for parallax accuracy evaluation in the camera module according to Embodiment 3 of the present invention. A region indicated by Bi (also indicated by I 1 ) is the i-th block obtained from the first imaging signal I 1  in Step S 3230 . A region indicated by I 4  is a region obtained by moving Bi by Δi in the x direction and Δi in the y direction. Then, for all image signals I 1 ( x,y ) and I 4 ( x−Δi,y−Δi ) in these regions, correlation values for parallax accuracy evaluation R 2   i  are given as in Equation (60) below. Here, Σ Σ represents a sum in the block Bi, and avg represents an average in the block Bi. Next, Step S 3252  is executed. 
     
       
         
           
             
               
                 
                   
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     In Step S 3252 , a parallax correction mode for each block Bi is selected based on the correlation value for parallax accuracy evaluation R 2   i . When the correlation value for parallax accuracy evaluation R 2   i  is larger than a threshold R 20  as in Equation (61) below, 1 indicating a usual parallax correction is substituted into a parallax correction mode flag Fi and stored in the memory of the system control portion  331 . Next, Step S 3261  is executed.
 
 Fi= 1( R 2 i&gt;R 20)  (61)
 
     In Step S 3261 , the contrast computing portion  345  computes the contrast value for parallax accuracy evaluation for each block using the data in the memory in the system control portion  331 . Then, the contrast computing portion  345  writes it into the memory in the system control portion  331 . An absolute value of Laplacian, which is a sum of second order differentials in the x and y directions, is computed as per Equation (62) below and further is subjected spatially to a LPF (low-pass filter) as per Equation (63) below, and the result is averaged in each block Bi as per Equation (64) below, thereby obtaining a contrast evaluation value for parallax accuracy evaluation C 6   i , which is to be written into the memory in the system control portion  331 . Here, NBi represents the number of pixels in the block Bi. It should be noted that the contrast evaluation value is not limited to Equations (62) to (64) and may be any value as long as it can express the contrast. For example, in Equation (62), a first derivation may be used instead of Laplacian, or a sum of absolute second order differentials in the x and y directions, respectively, may be used instead of the absolute value of Laplacian. Also, LPFs other than Equation (63) also may be used. Further, the result of Equation (64) also may be normalized by division by an average of the intensity of I 1 . Next, Step S 3262  is executed. 
     
       
         
           
             
               
                 
                   
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                   ( 
                   64 
                   ) 
                 
               
             
           
         
       
     
     In Step S 3262 , a parallax correction mode for each block Bi is selected based on the contrast evaluation value for parallax accuracy evaluation C 6   i . Here, in Step S 3262 , only the block in which 1 is not substituted into the parallax correction mode flag Fi in Step S 3252  is evaluated. Accordingly, in Step S 3261 , in the block Bi with the parallax correction mode flag Fi=1, the computation of the contrast value for parallax accuracy evaluation C 6   i  may be omitted. When the contrast evaluation value for parallax accuracy evaluation C 6   i  is smaller than a threshold C 60  as in Equation (65) below, 2 indicating a parallax correction for low contrast is substituted into the parallax correction mode flag Fi and stored in the memory of the system control portion  331 . Also, when the contrast evaluation value for parallax accuracy evaluation C 6   i  is equal to or larger than the threshold C 60  as in Equation (66) below, 3 indicating a parallax correction for low correlation is substituted into the parallax correction mode flag Fi and stored in the memory of the system control portion  331 . Next, Step S 3271  is executed.
 
 Fi= 2( C 6 i&lt;C 60 and  Fi≠ 1)  (65)
 
 Fi= 3( C 6 i≧C 60 and  Fi≠ 1)  (66)
 
     In Step S 3271 , whether or not a block re-division is necessary is judged based on the parallax correction mode flag and a block size, and the operation is branched according to the result. When the parallax correction mode flag Fi of at least one block is 3 and the number of pixels of the smallest block among all the blocks Bi is larger than S 0 , the block re-division is judged to be necessary (the result of judgment in Step S 3271  is Yes), and then Step S 3272  is executed. When the parallax correction mode flags Fi of all the blocks are 1 or 2 or the number of pixels of the smallest block among all the blocks Bi is equal to or smaller than S 0 , the block re-division is judged to be unnecessary (the result of judgment in Step S 3271  is No), and then Step S 3280  is executed. 
     In Step S 3272 , the block re-dividing portion  346  re-divides the block using the data in the memory in the system control portion  331 .  FIG. 31A  is a drawing for describing the state before the block re-division in the camera module according to Embodiment 3 of the present invention, and  FIG. 31B  is a drawing for describing the state after the block re-division in the camera module according to Embodiment 3 of the present invention. For the sake of simplicity,  FIG. 31  illustrates an example in which there are four blocks and a block B 2  where 3 indicating the parallax correction for low correlation is substituted into the parallax correction mode flag Fi (see  FIG. 31A ) is divided into four blocks B 2 , B 4 , B 5  and B 6  (see  FIG. 31B ). The numbers indicating the blocks after re-dividing the block B 2  are the number of the divided block (i.e., 2) and unassigned numbers (i.e., 4, 5 and 6). Next, S 3240  is executed. 
     The above-described operations of re-dividing the block with low correlation (Fi=3) (Step S 3272 ), computing the parallax for the re-divided block (Step S 3240 ), computing and evaluating the correlation (Step S 3251  and Step S 3252 ), computing and evaluating the contrast (Step S 3261  and Step S 3262 ), judging whether or not the block is to be re-divided (Step S 3271 ) and further re-dividing the block with low correlation (Fi=3) (Step S 3272 ) are repeated until the size of the smallest block among all the blocks reaches S 0  or until the parallax correction mode flags Fi of all the blocks become 1 or 2. Incidentally, since the block size and block number are changed with the block re-division in Steps S 3240  to S 3272 , the operations in these steps are modified suitably. 
     By the above processes, when the judgment result in Step S 3271  described above becomes N (namely, when the execution of Step S 3280  is started), 1 indicating the usual parallax correction, 2 indicating the parallax correction for low contrast or 3 indicating the parallax correction for low correlation is substituted in the parallax correction mode flags Fi of all the blocks Bi including the block divided in Step S 3272 . In Step S 3280 , the usual parallax correcting portion  347 , the parallax correcting portion for low contrast  348  and the parallax correcting portion for low correlation  349  utilize the data in the memory in the system control portion  331 , perform the parallax correction according to the value of the parallax correction mode flags Fi for each block so as to perform an image synthesis, and write the result into the memory of the system control portion  331 . 
     In Step S 3280 , in the block with the parallax correction mode flag Fi=1, the correlation value for parallax accuracy evaluation R 2   i  is large.  FIG. 32  is a drawing for describing the relationship between the correlation value for parallax accuracy evaluation R 2   i  and the parallax correction mode flag Fi in the camera module according to Embodiment 3 of the present invention. The correlation value for parallax accuracy evaluation R 2   i  obtained in Step S 3251  is 1 when the first imaging signal I 1 ( x,y ) and the fourth imaging signal I 4 ( x−Δi,y−Δi ) shifted therefrom by the parallax Δi in the x and y directions in the i-th block Bi match with each other, 0 when they differ randomly as in a random noise and −1 when they are in an inverse relationship or the like. As described above, the correlation value for parallax accuracy evaluation R 2   i  is large and close to 1 when these imaging signals are similar, and small and away from 1 when they are not similar. Here, the threshold R 20  is set to a value close to 1 (for example, 0.9) as shown in  FIG. 32 , and when the correlation value for parallax accuracy evaluation R 2   i  is larger than the threshold R 20 , it can be judged that the first imaging signal I 1 ( x,y ) and the fourth imaging signal I 4 ( x−Δi,y−Δi ) shifted therefrom by the parallax Δi in the i-th block Bi are similar. This indicates that the accuracy of the parallax Δi is high and there are only the subjects at the same distance between the first imaging signal I 1 ( x,y ) and the fourth imaging signal I 4  ( x−Δi,y−Δi ) shifted therefrom by the parallax Δi in the i-th block Bi. Thus, by shifting the fourth imaging signal I 4  by Δi in the x direction and by Δi in the y direction, it is possible to reproduce an imaging signal in the i-th block Bi. Now, the second imaging signal I 2  has a parallactic influence only in the x direction, and the third imaging signal I 3  has a parallactic influence only in the y direction. Therefore, by shifting the second imaging signal I 2  by Δi in the x direction, it is possible to reproduce a blue imaging signal in the block Bi. By shifting the third imaging signal I 3  by Δi in the y direction, it is possible to reproduce a red imaging signal in the block Bi. 
     Accordingly, in the block with the parallax correction mode flag Fi=1, the normal parallax correcting portion  347  utilizes data in the memory in the system control portion  331 , carries out a parallax correction for each block using the parallax value corresponding to this block, and then performs an image synthesis. Then, the usual parallax correcting portion  347  writes the result into the memory in the system control portion  331 . Since the first imaging device  123   a  and the fourth imaging device  123   d  mainly receive the green component of the object light, the first imaging signal I 1  and the fourth imaging signal I 4  are information signals of the green component of the object light. Also, since the second imaging signal  123   b  mainly receives the blue component of the object light, the second imaging signal I 2  is an information signal of the blue component of the object light. Further, since the third imaging signal  123   c  mainly receives the red component of the object light, the third imaging signal I 3  is an information signal of the red component of the object light. Since the parallax between the first imaging device  123   a  and the fourth imaging device  123   d  is calculated to be (Δi, Δi) in the i-th block Bi, G(x,y) indicating the intensity of green at the pixel coordinates (x,y) is given by an average of the first imaging signal I 1 ( x,y ) and the fourth imaging signal I 4 ( x−Δi,y−Δi ) as in Equation (67) below. By taking an average as above, the influence of random noise can be reduced. Also, since the parallax between the first imaging device  123   a  and the second imaging device  123   b  is calculated to be (Δi, 0), B(x,y) indicating the intensity of blue at the pixel coordinates (x,y) is given by the second imaging signal I 2 ( x−Δi,y ) as in Equation (68) below. Further, since the parallax between the first imaging device  123   a  and the third imaging device  123   c  is calculated to be (0,Δi), R(x,y) indicating the intensity of red at (x,y) is given by the third imaging signal I 3 ( x,y−Δi ) as in Equation (69) below.
 
 G ( x,y )=[ I 1( x,y )+ I 4( x−Δi,y−Δi )]/2  (67)
 
 B ( x,y )= I 2( x−Δi,y )  (68)
 
 R ( x,y )= I 3( x,y−Δi )  (69)
 
     In Step S 3280 , in the block with the parallax correction mode flag Fi=2, the correlation value for parallax accuracy evaluation R 2   i  is small, and the contrast evaluation value for parallax accuracy evaluation C 6   i  is small.  FIG. 33  is a drawing for describing the relationship between the contrast evaluation value for parallax accuracy evaluation and the parallax correction mode flag in the camera module according to Embodiment 3 of the present invention. The contrast evaluation value for parallax accuracy evaluation C 6  obtained in Step S 3261  increases when the first imaging signal I 1 ( x,y ) in the i-th block Bi shows a clear image, i.e., an image with a large variation in light and dark and becomes close to 0 when it shows a blurred image, i.e., an image with a small variation in light and dark. Here, the threshold C 60  is set as shown in  FIG. 33 , and when the contrast evaluation value for parallax accuracy evaluation is smaller than the threshold C 60 , an image shown by the first imaging signal I 1 ( x,y ) in the i-th block Bi is an image with a small variation in light and dark. Thus, it can be judged that a noise component increases with respect to a signal component, resulting in a poor accuracy of the parallax Δi. Also, because of the small variation in light and dark, there is no practical problem if the image to be reproduced may contain some error. Accordingly, colors are reproduced mainly based on information of the first imaging signal I 1 ( x,y ). It should be noted that colors also may be reproduced based on information of the second imaging signal I 2 ( x,y ), the third imaging signal I 3 ( x,y ) or the fourth imaging signal I 4 ( x,y ). However, since the visibility is the highest for green compared with red and blue, it is preferable that the colors are reproduced based on the first imaging signal I 1 ( x,y ) or the fourth imaging signal I 4 ( x,y ) having information of the green component of object light. Further, because of a poor accuracy of the parallax Δi, it is preferable to use the first imaging signal I 1 ( x,y ) or the fourth imaging signal I 4 ( x,y ) alone. 
     Accordingly, in the block with the parallax correction mode flag Fi=2, the parallax correcting portion for low contrast  348  utilizes data in the memory in the system control portion  331 , carries out a parallax correction for each block using the parallax value corresponding to this block, and then performs an image synthesis. Then, the parallax correcting portion for low contrast  348  writes the result into the memory in the system control portion  331 . Since the first imaging device  123   a  and the fourth imaging device  123   d  mainly receive the green component of the object light, the first imaging signal I 1  and the fourth imaging signal I 4  are information signals of the green component of the object light. Also, since the second imaging signal  123   b  mainly receives the blue component of the object light, the second imaging signal I 2  is an information signal of the blue component of the object light. Further, since the third imaging signal  123   c  mainly receives the red component of the object light, the third imaging signal I 3  is an information signal of the red component of the object light. Since the parallax between the first imaging device  123   a  and the fourth imaging device  123   d  is calculated to be (Δi, Δi) in the i-th block Bi but there probably is a large error, G(x,y) indicating the intensity of green at the pixel coordinates (x,y) is given by the first imaging signal I 1 ( x,y ) as in Equation (70) below. Also, B(x,y) indicating the intensity of blue is given by multiplying the first imaging signal I 1 ( x,y ) by a factor of proportionality kB as in Equation (71) below. Here, the factor of proportionality kB is a constant. Incidentally, the factor of proportionality kB may be changed for each block Bi and may be the ratio of a value at the center of the block Bi of the second imaging signal I 2 ( x,y ) with respect to that of the first imaging signal I 1 ( x,y ), the ratio of a value at the center of the block Bi of the second imaging signal I 2 ( x−Δi,y ) shifted from the first imaging signal I 1 ( x,y ) by the parallax Δi in the x direction with respect to that of the first imaging signal I 1 ( x,y ), the ratio of an average of the second imaging signal I 2 ( x,y ) with respect to that of the first imaging signal I 1 ( x,y ) in the block Bi or the ratio of an average of the second imaging signal I 2 ( x−Δi,y ) shifted from the first imaging signal I 1 ( x,y ) by the parallax Δi in the x direction with respect to that of the first imaging signal I 1 ( x,y ) in the block Bi. Further, R(x,y) indicating the intensity of red is given by multiplying the first imaging signal I 1 ( x,y ) by a factor of proportionality kR as in Equation (72) below. Here, the factor of proportionality kR is a constant. Incidentally, the factor of proportionality kR may be changed for each block Bi and may be the ratio of a value at the center of the block Bi of the third imaging signal I 3 ( x,y ) with respect to that of the first imaging signal I 1 ( x,y ), the ratio of a value at the center of the block Bi of the third imaging signal I 3 ( x,y−Δi ) shifted from the first imaging signal I 1 ( x,y ) by the parallax Δi in the y direction with respect to that of the first imaging signal I 1 ( x,y ), the ratio of an average of the third imaging signal I 3 ( x,y ) with respect to that of the first imaging signal I 1 ( x,y ) in the block Bi or the ratio of an average of the third imaging signal I 3 ( x,y−Δi ) shifted from the first imaging signal I 1 ( x,y ) by the parallax Δi in the y direction with respect to that of the first imaging signal I 1 ( x,y ) in the block Bi. Incidentally, considering that some errors would not be noticeable because of the small variation in light and dark, similarly to the case of the parallax correction mode flag Fi=1, since the parallax between the first imaging device  123   a  and the second imaging device  123   b  is calculated to be (Δi, 0), B(x,y) indicating the intensity of blue at the pixel coordinates (x,y) may be given by the second imaging signal I 2 ( x−Δi,y ) as in Equation (68). Further, since the parallax between the first imaging device  123   a  and the third imaging device  123   c  is calculated to be (0,Δi), R(x,y) indicating the intensity of red at (x,y) may be given by the third imaging signal I 3 ( x,y−Δi ) as in Equation (69).
 
 G ( x,y )= I 1( x,y )  (70)
 
 B ( x,y )= I 1( x,y )* kB   (71)
 
 R ( x,y )= I 1( x,y )* kR   (72)
 
     In Step S 3280 , in the block with the parallax correction mode flag Fi=3, the correlation value for parallax accuracy evaluation R 2   i  is small, and the contrast evaluation value for parallax accuracy evaluation C 6   i  is large. Now, the threshold R 20  is set to a value close to 1 (for example, 0.9) as shown in  FIG. 32 , and when the correlation value for parallax accuracy evaluation R 2   i  is smaller than the threshold R 20 , it can be judged that the first imaging signal I 1 ( x,y ) and the fourth imaging signal I 4  ( x−Δi,y−Δi ) shifted therefrom by the parallax Δi in the i-th block Bi are not similar. This indicates that there are a plurality of subjects at different subject distances in the i-th block Bi and the parallax Δi cannot deal with all of the subjects. 
     Accordingly, in the block with the parallax correction mode flag Fi=3, the parallax correcting portion for low correlation  349  utilizes data in the memory in the system control portion  331 , re-divides the block further into plural blocks using edges, carries out a parallax correction, and then performs an image synthesis. Then, the parallax correcting portion for low correlation  349  writes the result into the memory in the system control portion  331 .  FIG. 34  is a flowchart showing an operation of the parallax correcting portion for low correlation  349  according to Embodiment 3 of the present invention. 
     In Step S 3310 , the operation of the parallax correcting portion for low correlation  349  is started. Next, Step S 3320  is executed. 
     In Step S 3320 , a contrast evaluation value for edge detection is computed. This computation is performed only for the first imaging signal I 1 . Laplacian is computed as per Equation (73) below and further is subjected spatially to a LPF (low-pass filter) as per Equation (74) below, and the result is given as a contrast evaluation value for edge detection C 8 ( x,y ).  FIG. 35A  shows an original image for describing the edge detection of the parallax correcting portion for low correlation  349  of the camera module according to Embodiment 3 of the present invention, and  FIG. 35B  shows an image of the contrast evaluation value for edge detection for describing the edge detection of the parallax correcting portion for low correlation  349  of the camera module according to Embodiment 3 of the present invention. From Equations (73) and (74), the contrast evaluation value for edge detection C 8 ( x,y ) of the original image in  FIG. 35A  is calculated, which is shown in  FIG. 35B . It should be noted that black in  FIG. 35B  indicates where an absolute value of Equation (74) is large. Next, Step S 3330  is executed. 
     
       
         
           
             
               
                 
                   
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     In Step S 3330 , the edges are detected.  FIG. 35C  shows an image of the edges for describing the edge detection of the parallax correcting portion for low correlation  349  of the camera module according to Embodiment 3 of the present invention. By sensing a zero crossing (a point at which a value changes from positive to negative and a point at which a value changes from negative to positive) of the contrast evaluation value for edge detection C 8 ( x,y ) in  FIG. 35B , it is possible to detect the edges as shown in  FIG. 35C . Next, Step S 3340  is executed. 
     In Step S 3340 , the block is re-divided. As shown in  FIG. 35C , numbers such as Bi, Bj, Bj+1, . . . , Bj+n are assigned to regions surrounded by the edges. It should be noted that j, j+1, . . . , j+n are unassigned numbers for indicating blocks. Here, for the sake of simplicity,  FIG. 35  illustrates an example in which the block Bi is re-divided into 5 blocks and n=3. Incidentally, in order to prevent erroneous detection and loss of the edges due to noise or the like, the edges also may be corrected using a dilation algorithm or an erosion algorithm. Next, Step S 3350  is executed. 
     In Step S 3350 , a parallax value is computed for each block. This operation is similar to that in Step S 3240 , and the description thereof will be omitted. Next, Step S 3360  is executed. 
     In Step S 3360 , a parallax is corrected, and an image synthesis is performed. This operation is similar to that of the usual parallax correcting portion  347 , and the description thereof will be omitted. Next, Step S 3370  is executed. 
     In Step S 3370 , the operation of parallax correction for low correlation is ended. 
     Step S 3280  is operated as described above, and then Step S 3290  is executed. 
     In Step S 3290 , the parallax correction is ended, thus returning to a main routine. In other words, Step S 3800  shown in  FIG. 25  is executed next. 
     In Step S 3800 , an image is outputted. The input/output portion  136  outputs G(x,y), B(x,y) and R(x,y), which are data in the memory in the system control portion  331 , to the main CPU (not shown) and the external display (not shown). It should be noted that a luminance signal or a color difference signal, for example, may be outputted instead of G(x,y), B(x,y) and R(x,y). Also, values after the image processings such as a white-balance correction and a γ correction may be outputted. Further, reversibly compressed data or irreversibly compressed data such as JPEG may be outputted. Moreover, a plurality of them may be outputted. Next, S 3900  is executed. 
     In Step S 3900 , the operation ends. 
     With the above-described configuration and operations, the following effects are achieved. 
     As in Equation (1), the relative positions of the four object images formed respectively by the first lens portion  113   a , the second lens portion  113   b , the third lens portion  113   c  and the fourth lens portion  113   d  vary according to the subject distance A. In other words, when the subject distance A decreases, the parallax Δ increases. Accordingly, when a plurality of subjects at different distances are shot at the same time, the parallaxes A for the individual subjects are different. In the camera module according to Embodiment 3, the entire image region is divided into blocks in Step S 3230 , the parallax for each block is computed in Step S 3240 , and the parallax correction is carried out by the image synthesis based on the parallax for each block so as to reduce the parallactic influence in Step S 3280 . In this manner, even when a plurality of subjects at different distances are shot at the same time, it is possible to correct the parallaxes of the individual subjects suitably, thereby achieving a beautiful image with reduced parallactic influence over the entire image region. 
     In the camera module according to Embodiment 3, the entire image region is divided into rectangular blocks in Step S 3230 , the parallax for each block is computed in Step S 3240 , and the parallax correction is carried out by the image synthesis based on the parallax for each block so as to reduce the parallactic influence in Step S 3280 . In this manner, even when a plurality of subjects at different distances are shot at the same time, it is possible to correct the parallaxes of the individual subjects suitably, thereby achieving a beautiful image with reduced parallactic influence over the entire image region. 
     Also, the block divided in Step S 3230  sometimes contains a plurality of objects at different subject distances. In this case, the parallaxes for the individual objects are different. In the camera module according to Embodiment 3, the correlation value for parallax accuracy evaluation R 2   i  is computed in Step S 3251 , the correlation value for parallax accuracy evaluation R 2   i  is evaluated so as to evaluate the accuracy of the parallax Δi in Step S 3252 , the contrast evaluation value for parallax accuracy evaluation C 6   i  is computed in Step S 3261 , the contrast evaluation value for parallax accuracy evaluation C 6   i  is evaluated so as to evaluate the accuracy of the parallax Δi, and the parallax correction mode flag Fi is set, thus determining the mode of parallax correction in Step S 3262 . In this manner, it is possible to correct an image by an optimal correction method for each block, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     Moreover, in the camera module according to Embodiment 3, the contrast evaluation value for parallax accuracy evaluation C 6   i  is computed in Step S 3261 , the accuracy of the parallax Δi computed for each block is judged according to the degree of contrast of the contrast evaluation value for parallax accuracy evaluation C 6   i  for each block in Step S 3262 . When the contrast is large, the parallax correction mode flag Fi is set to 1, followed by the normal parallax correction in Step S 3280 . When the contrast is small, the parallax correction mode flag Fi is set to 2, followed by the parallax correction for low contrast in Step S 3280 . In this manner, it is possible to correct an image by an optimal correction method for each block, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     Moreover, in the camera module according to Embodiment 3, the correlation value for parallax accuracy evaluation R 2   i  is computed in Step S 3251 . The correlation value for parallax accuracy evaluation R 2   i  is one of parallax accuracy evaluation values indicating the accuracy of the parallax computed for each block and a value indicating how much an image shifted by the parallax is correlated with the original image. When the correlation value for parallax accuracy evaluation R 2   i  is large in Step S 3252 , the usual parallax correction is carried out in Step S 3280 . When the correlation value for parallax accuracy evaluation R 2   i  is small, the parallax correction for low correlation is carried out in Step S 3280 . In this manner, it is possible to correct an image by an optimal correction method for each block, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     Furthermore, in the camera module according to Embodiment 3, the correlation value for parallax accuracy evaluation R 2   i  is computed in Step S 3251 . The correlation value for parallax accuracy evaluation R 2   i  is one of parallax accuracy evaluation values indicating how accurate the parallax computed for each block is and a value indicating how much an image shifted by the parallax is correlated with the original image. When the correlation value for parallax accuracy evaluation R 2   i  is large, the usual parallax correction is carried out in Step S 3280 . When the correlation value for parallax accuracy evaluation R 2   i  is small, the parallax correcting portion for low correlation  349  re-divides the block and carries out the parallax correction for each of the re-divided blocks in Steps S 3272  and S 3340 . In other words, the block that is judged to have a low correlation is re-divided. In this manner, it is possible to correct an image by an optimal correction method for each block, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     Additionally, in the camera module according to Embodiment 3, the correlation value for parallax accuracy evaluation R 2   i  is computed in Step S 3251 . The correlation value for parallax accuracy evaluation R 2   i  is one of parallax accuracy evaluation values indicating how accurate the parallax computed for each block is and a value indicating how much an image shifted by the parallax is correlated with the original image. In Step S 3261 , the contrast evaluation value for parallax accuracy evaluation C 6   i  is computed. The contrast evaluation value for parallax accuracy evaluation C 6   i  is one of parallax accuracy evaluation values indicating how accurate the computed parallax is and a value indicating how high the contrast is. When the correlation value for parallax accuracy evaluation R 2   i  is large and the contrast evaluation value for parallax accuracy evaluation C 6   i  is large, the usual parallax correction is carried out in Step S 3280 . When the correlation value for parallax accuracy evaluation R 2   i  is small and the contrast evaluation value for parallax accuracy evaluation C 6   i  is small, the parallax correction for low contrast is carried out in Step S 3280 . When the correlation value for parallax accuracy evaluation R 2   i  is small and the contrast evaluation value for parallax accuracy evaluation C 6   i  is large, the parallax correcting portion for low correlation  349  re-divides the block and carries out the parallax correction for each of the re-divided blocks in Steps S 3272  and S 3340 . In other words, the block that is judged to have a low correlation and a high contrast is re-divided. In this manner, it is possible to correct an image by an optimal correction method for each block, thereby achieving a beautiful image with further reduced parallactic influence over the entire image region. 
     Incidentally, in Embodiment 3, the timing of the image output is not limited to the above, and a preview may be outputted suitably. For example, in Embodiment 3, during the automatic focusing control in Step S 3100 , an image without parallax correction may be outputted. Further, it also may be possible to update a preview screen by carrying out the parallax correction for only the blocks whose parallax can be corrected after Step S 3271  without correcting parallaxes for the other blocks. 
     Also, in Embodiment 3, the contrast evaluation value for edge detection C 8 ( x,y ) is computed as per Equation (74) in Step S 3320 , and the edges are detected from zero crossing in Step S 3330 . However, there is no limitation to the above. For example, it also may be possible to create a histogram in the block and use the minimum value as the threshold so as to perform the block division by binarization. Here, the number of the thresholds may be more than one. In addition, the edges may be detected using an absolute value of first order differentials. 
     Embodiment 4 
     In the case of an interlaced reading, Embodiment 4 of the present invention computes parallaxes for individual fields so as to synthesize images and synthesizes the images synthesized for the individual fields, thus obtaining a final image. By computing the parallaxes for the individual fields in this manner, even in the case where the images of the individual fields are different because shooting times for the individual fields are different when shooting a moving subject, it is possible to compute the parallaxes for the individual fields properly and synthesize the images using these parallaxes, so that a beautiful image with further reduced parallactic influence can be achieved over an entire image region. 
     In the following, a camera module according to Embodiment 4 of the present invention will be described, with reference to the accompanying drawings. 
       FIG. 36  is a sectional view showing a configuration of the camera module according to Embodiment 4 of the present invention. The configuration is similar to that of Embodiment 1 except for an SLSI  425  of a circuit portion  420  of a camera module  401 . Members similar to those in Embodiment 1 are assigned the same reference numerals, and the description thereof will be omitted. 
       FIG. 37  is a block diagram showing the camera module according to Embodiment 4 of the present invention. The SLSI  425  includes a system control portion  431 , an imaging device driving portion  132 , an imaging signal input portion  133 , an actuator operation amount output portion  134 , an image processing portion  435  and an input/output portion  136 . Also, the circuit portion  420  includes an amplifier  126  in addition to the configuration described above. 
     The image processing portion  435  is configured so as to include a logic circuit, a DSP (digital signal processor) or both of the logic circuit and the DSP and carries out various image processings utilizing memory information in the system control portion  431 . The image processing portion  435  includes an automatic focusing control portion  341 , a block division portion  342 , a parallax computing portion  343 , a correlation computing portion  344 , a contrast computing portion  345 , a block re-dividing portion  346 , a usual parallax correcting portion  347 , a parallax correcting portion for low contrast  348 , a parallax correcting portion for low correlation  349  and a frame image creating portion  451 . 
       FIGS. 38A to 38D  are drawings for describing field images of the camera module according to Embodiment 4 of the present invention. As shown in  FIG. 38A , in the entire image, first field images and second field images are arranged alternately. First, an imaging signal composing the first field image is transferred, and then an imaging signal composing the second field image is transferred. For a usual black-and-white image, each line of these field images is arranged alternately, thereby reproducing the entire image. When L indicates the width of the entire image (frame image) and H indicates the height thereof as in  FIG. 38B , the first field image and the second field image respectively have a width of L and a height of H/2 as shown in  FIG. 38C  and  FIG. 38D . 
       FIG. 39  is a flowchart showing an operation of the camera module according to Embodiment 4 of the present invention, and  FIG. 40  is a timing chart showing the operation of the camera module according to Embodiment 4 of the present invention. The camera module  401  is operated as per these flowchart and timing chart by the system control portion  431  of the SLSI  425 . 
     In Step S 4000 , the operation starts. For example, the main CPU (not shown) senses that a shutter button (not shown) or the like is pressed down, and instructs the camera module  401  to start operating via the input/output portion  136 , whereby the camera module  401  starts operating. Next, Step S 4100  is executed. 
     In Step S 4100 , the automatic focusing control portion  341  executes an automatic focusing control. This operation is similar to that in Step S 3100  in Embodiment 3, and the description thereof will be omitted. However, since only the first field is transferred and only the first field image is used as shown in  FIG. 40 , modifications are made suitably. Thus, the time needed for transferring is reduced substantially by half compared with the case of transferring the entire image (the first fields and the second fields), so that the time for automatic focusing control can be shortened accordingly. Next, Step S 4200  is executed. 
     In Step S 4200 , a parallax correction of the first field is executed. This operation is similar to that in Step S 3200  in Embodiment 3, and the description thereof will be omitted. However, modifications are made suitably so that only the first field is transferred and only the first field image is used as shown in  FIG. 40 , thus creating Rf 1 ( x,y ) indicating the intensity of red, Gf 1 ( x,y ) indicating the intensity of green and Bf 1 ( x,y ) indicating the intensity of blue of the first field. Next, Step S 4300  is executed. 
     In Step S 4300 , a parallax correction of the second field is executed. This operation is similar to that in Step S 3200  in Embodiment 3, and the description thereof will be omitted. However, modifications are made suitably so that only the second field is transferred and only the second field image is used as shown in  FIG. 40 , thus creating Rf 2 ( x,y ) indicating the intensity of red, Gf 2 ( x,y ) indicating the intensity of green and Bf 2 ( x,y ) indicating the intensity of blue of the second field. Next, Step S 4400  is executed. 
     In Step S 4400 , a frame image (entire image) is created. Rf 1 ( x,y ) indicating the intensity of red in the first frame serves as R(x,2*y) indicating the intensity of red in even-numbered lines of the frame image as in Equation (75) below, and Rf 2 ( x,y ) indicating the intensity of red in the second frame serves as R(x,2*y+1) indicating the intensity of red in odd-numbered lines of the frame image as in Equation (76) below. Also, Gf 1 ( x,y ) indicating the intensity of green in the first frame serves as G(x,2*y) indicating the intensity of green in even-numbered lines of the frame image as in Equation (77) below, and Gf 2 ( x,y ) indicating the intensity of green in the second frame serves as G(x,2*y+1) indicating the intensity of green in odd-numbered lines of the frame image as in Equation (78) below. Further, Bf 1 ( x,y ) indicating the intensity of blue in the first frame serves as B(x,2*y) indicating the intensity of blue in even-numbered lines of the frame image as in Equation (79) below, and Bf 2 ( x,y ) indicating the intensity of blue in the second frame serves as B(x,2*y+1) indicating the intensity of blue in odd-numbered lines of the frame image as in Equation (80) below. Here, x is varied from 0 to L−1, and y is varied from 0 to H/2−1. Next, Step S 4800  is executed.
 
 R ( x, 2 *y )= Rf 1( x,y )  (75)
 
 R ( x, 2* y+ 1)= Rf 2( x,y )  (76)
 
 G ( x, 2* y )= Gf 1( x,y )  (77)
 
 G ( x, 2 *y+ 1)= Gf 2( x,y )  (78)
 
 B ( x, 2 *y )= Bf 1( x,y )  (79)
 
 B ( x ,2 *y+ 1)= Bf 2( x,y )  (80)
 
     In Step S 4800 , an image is outputted. This operation is similar to that in Embodiment 3, and the description thereof will be omitted. Next, S 4900  is executed. 
     In Step S 4900 , the operation ends. 
     With the above-described configuration and operations, the camera module according to Embodiment 4 has the effects similar to Embodiment 3. 
     In the camera module according to Embodiment 4, in the case of the interlaced reading, the parallax of the first field is computed in Step S 4200 , and the parallax correction is carried out based on the computed parallax, thus creating the image (Rf 1 , Gf 1 , Bf 1 ). Also, the parallax of the second field is computed in Step S 4300 , and the parallax correction is carried out based on the computed parallax, thus creating the image (Rf 2 , Gf 2 , Bf 2 ). Further, the images synthesized for the individual fields are synthesized in Step S 4400 , thus obtaining the final image. By computing the parallaxes for individual fields in this manner, even in the case where the images of the individual fields are different because shooting times for the individual fields are different when shooting a moving subject, it is possible to compute the parallaxes for the individual fields properly. This allows the image synthesis using these parallaxes, so that a beautiful image with further reduced parallactic influence can be achieved over an entire image region. 
     Although the number of fields is 2 in the camera module according to Embodiment 4, there is no limitation to this. There may be more fields (for example, 3 fields or 4 fields). 
     Although the images for the individual fields are created in the camera module according to Embodiment 4, a region in the frame image may be prepared in advance so as to allow a direct substitution. Also, it also may be possible to retain parallax information for the individual fields and create the frame image directly without creating any field image. 
     Moreover, in the camera module according to Embodiment 4, two color filters adjacent to each other in the X direction among the first color filter  124   a , the second color filter  124   b , the third color filter  124   c  and the fourth color filter  124   d  may have spectral transmittance characteristics mainly transmitting green as shown respectively in  FIGS. 41A and 41B . Incidentally, in  FIGS. 41A to 41C , signs R, G and B indicate the colors transmitted by the respective color filters. With the configuration of  FIG. 41A  or  41 B, two imaging devices adjacent to each other in the X direction in the imaging device  123  (namely, the first imaging device  123   a  and the second imaging device  123   b , or the third imaging device  123   c  and the fourth imaging device  123   d ) receive a green component in the object light. 
     Alternatively, the first color filter  124   a , the second color filter  124   b , the third color filter  124   c  and the fourth color filter  124   d  may be arranged as shown in  FIG. 41C , and two color filters adjacent to each other in the X direction (in this example, the second color filter  124   b  and the third color filter  124   c ) may have spectral transmittance characteristics mainly transmitting green. Incidentally, in the case where four color filters are arranged as shown in  FIG. 41C , the first lens portion  113   a , the second lens portion  113   b , the third lens portion  113   c  and the fourth lens portion  113   d  in the lens portion  113  are arranged so that their optical axes match with the centers of these color filters. Similarly, the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d  in the imaging device  123  also are arranged according to the arrangement of the individual lens portions in the lens portion  113 . Here, modifications are made suitably so that the parallax is computed from the first imaging signal I 1  and the second imaging signal I 2 . 
     By adopting the arrangement of the color filters as shown in  FIGS. 41A to 41C , the camera module  401  according to the present embodiment has the following advantage. Since the parallax is computed by comparing the first imaging signal I 1  and the second imaging signal I 2 , the parallax is generated only in the x direction and does not extend over the fields. Thus, a more accurate parallax can be computed. 
     It should be noted that  FIGS. 41A to 41C  only illustrate examples of preferable arrangements of the color filters, and the embodiment of the present invention is not limited to them. For example, the positions of the color filters indicated by B and R may be reversed. 
     Embodiment 5 
     Embodiment 5 of the present invention recognizes a block with a small parallax, namely, a large subject distance as a background and replaces it with another image such as a background image that is stored in advance. By combining the image corrected based on the parallax and another image in this manner, it becomes possible to extract an image in a part with a large parallax properly from the corrected image, so that these images can be combined beautifully. 
     In the following, a camera module according to Embodiment 5 of the present invention will be described, with reference to the accompanying drawings. 
       FIG. 42  is a sectional view showing a configuration of the camera module according to Embodiment 5 of the present invention. The configuration is similar to that of Embodiment 1 except for an SLSI  525  of a circuit portion  520  of a camera module  501 . Members similar to those in Embodiment 1 are assigned the same reference numerals, and the description thereof will be omitted. 
       FIG. 43  is a block diagram showing the camera module according to Embodiment 5 of the present invention. The SLSI  525  includes a system control portion  531 , an imaging device driving portion  132 , an imaging signal input portion  133 , an actuator operation amount output portion  134 , an image processing portion  535 , an input/output portion  136  and a background image storing portion  551 . Also, the circuit portion  520  includes an amplifier  126  in addition to the configuration described above. 
     The image processing portion  535  is configured so as to include a logic circuit, a DSP (digital signal processor) or both of the logic circuit and the DSP and carries out various image processings utilizing memory information in the system control portion  531 . The image processing portion  535  includes an automatic focusing control portion  341 , a block division portion  342 , a parallax computing portion  343 , a correlation computing portion  344 , a contrast computing portion  345 , a block re-dividing portion  346 , a usual parallax correcting portion  347 , a parallax correcting portion for low contrast  348 , a parallax correcting portion for low correlation  349  and a background image replacing portion  552 . 
     The background image storing portion  551  is configured by a rewritable memory such as a RAM or a flash memory, stores image information and is rewritten suitably from an external part via the input/output portion  136  and the system control portion  531 . 
       FIG. 44  is a flowchart showing an operation of the camera module according to Embodiment 5 of the present invention. The camera module  501  is operated as per this flowchart by the system control portion  531  of the SLSI  525 . 
     In Step S 5000 , the operation starts. For example, the main CPU (not shown) senses that a shutter button (not shown) or the like is pressed down, and instructs the camera module  501  to start operating via the input/output portion  136 , whereby the camera module  501  starts operating. Next, Step S 5100  is executed. 
     In Step S 5100 , the automatic focusing control portion  341  executes an automatic focusing control. This operation is similar to that in Step S 3100  in Embodiment 3, and the description thereof will be omitted. Next, Step S 5200  is executed. 
     In Step S 5200 , a parallax correction is executed. This operation is similar to that in Step S 3200  in Embodiment 3, and the description thereof will be omitted. Next, Step S 5300  is executed. 
     In Step S 5300 , a background is replaced. The image is not changed for pixels whose parallax Δi is larger than a threshold Δsh as in Equations (81), (82) and (83) below. On the other hand, the image is replaced with an image (Rback,Gback,Bback) stored in the background image storing portion  551  for pixels whose parallax Δi is equal to or smaller than the threshold Δsh as in Equations (84), (85) and (86) below. Incidentally, Δi indicates a parallax of the block Bi computed in Step S 5200 . Next, Step S 5800  is executed.
 
 R ( x,y )= R ( x,y )(Δ i&gt;Δsh )  (81)
 
 G ( x,y )= G ( x,y )(Δ i&gt;Δsh )  (82)
 
 B ( x,y )= B ( x,y )(Δ i&gt;Δsh )  (83)
 
 R ( x,y )= R back( x,y )(Δ i&lt;Δsh )  (84)
 
 G ( x,y )= G back( x,y )(Δ i&lt;Δsh )  (85)
 
 B ( x,y )= B back( x,y )(Δ i&lt;Δsh )  (86)
 
     In Step S 5800 , an image is outputted. This operation is similar to that in Embodiment 3, and the description thereof will be omitted. Next, S 5900  is executed. 
     In Step S 5900 , the operation ends. 
     With the above-described configuration and operations, the camera module according to Embodiment 5 has the effects similar to Embodiment 3. 
     Embodiment 5 of the present invention recognizes the block Bi with a small parallax Δi, namely, a large subject distance as the background and replaces it with the background image (Rback,Gback,Bback) that is stored in advance in Step S 5300 . By combining the image corrected based on the parallax and another image in this manner, it becomes possible to extract an image in a part with a large parallax properly from the corrected image, so that these images can be combined beautifully.  FIGS. 45A to 45C  are drawings for describing the background replacement in the camera module according to Embodiment 5 of the present invention. In accordance with Embodiment 5, in the case of shooting a human figure with a background of a mountain as shown in  FIG. 45A , for example, the parallax Δi of the human figure is large and the parallax Δi of the mountain in the background is small. Here, if the threshold Δsh of the parallax is set between the parallax of the human figure and that of the mountain, an image of the human figure with a background of the sea as shown in  FIG. 45C  can be created by replacing pixels of the mountain in the background with a background image of the sea stored in the background image storing portion (see  FIG. 45B ; (Rback,Gback,Bback)). 
     Embodiment 6 
       FIGS. 46A and 46B  illustrate an embodiment of an electronic apparatus according to the present invention. As shown in  FIGS. 46A and 46B , a camera-equipped mobile phone  600  as an embodiment of the electronic apparatus according to the present invention includes a speaker  601 , an antenna  602 , a liquid crystal display  603 , a key portion  605  and a microphone  606 , and can be folded on a hinge portion  604 . Also, a lens module  110  is built into a back side of the liquid crystal display  603  in the mobile phone  600  as shown in  FIG. 46B , thus allowing shooting of still pictures and moving pictures. 
     It should be noted that the electronic apparatus according to the present invention can be embodied not only as the mobile phone but also as a vehicle-mounted camera, a digital camera or a camera-equipped PDA. 
     Although several embodiments of the present invention have been illustrated above, they are just examples. When putting the present invention into practice, various modifications can be made as follows. 
     For example, although the computed parallaxes are used as they are in the camera module according to Embodiments 1 to 5, they also may be limited suitably. Depending on lens characteristics, the image becomes unclear when the subject distance A is smaller than a certain value. Accordingly, by setting this value as the minimum value of the subject distance A, the maximum value of the parallax Δ can be determined. A parallax larger than this value may be ignored as being an error. Also, in this case, a value with the second smallest parallax evaluation value may be adopted as the parallax. 
     Furthermore, in the camera module according to Embodiments 1 to 5, the parallax is computed from the first imaging signal I 1  (mainly indicating green) and the fourth imaging signal I 4  (mainly indicating green). However, the present invention is not limited to this. For example, because a violet subject contains a smaller green component and larger blue and red components, the computation from the first imaging signal I 1  (mainly indicating green) and the fourth imaging signal I 4  (mainly indicating green) sometimes is not possible. In this case, the parallax also may be computed from the second imaging signal I 2  (mainly indicating blue) and the third imaging signal I 3  (mainly indicating red). Further, if the parallax cannot be computed from the first parallax signal I 1  (mainly indicating green) and the fourth imaging signal I 4  (mainly indicating green) and the parallax cannot be computed from the second imaging signal I 2  (mainly indicating blue) and the third imaging signal I 3  (mainly indicating red), then it is appropriate to consider that no parallactic influence is present and there is no parallax. 
     Also, when the camera module according to Embodiments 1 to 5 is mounted on a camera, the first to fourth imaging devices  123   a  to  123   d  are arranged so that the second imaging device  123   a  is located on an upper side at the time of shooting and the third imaging device  123   c  is located on a lower side, whereby the upper side becomes sensitive to blue and the lower side becomes sensitive to red. Consequently, it is possible to achieve a more natural color reproduction for landscape photographs. 
     Further, when the parallax evaluation value has two prominent maximum values, the parallax for the larger may be adopted. Two maximum values appear because such a block contains a subject and a background and the subject distance and the background distance are different. Since the subject distance is smaller than the background distance, the parallax of the subject is larger than that of the background. Here, by adopting the larger parallax, the parallactic influence of the subject, which affects an image quality directly, can be reduced, though the parallactic influence of the background cannot be reduced. 
     Also, in Embodiments 1 to 5, the imaging device  123  is constituted by the first imaging device  123   a , the second imaging device  123   b , the third imaging device  123   c  and the fourth imaging device  123   d , and the imaging signal input portion  133  is constituted by the first imaging signal input portion  133   a , the second imaging signal input portion  133   b , the third imaging signal input portion  133   c  and the fourth imaging signal input portion  133   d . However, it also may be possible to constitute the imaging device  123  by a single imaging device and form four images by the first to fourth lens portions  113   a  to  113   d  at different positions on the light-receiving surface of this imaging device. Further, the imaging signal input portion  133  also may be constituted by a single imaging signal input portion to which a signal from the single imaging device  123  is inputted. In this case, it is appropriate to select suitably regions from the data in the memory in the system control portions  131 ,  231 ,  331 ,  431  and  531  and use them as the first imaging signal I 1 , the second imaging signal I 2 , the third imaging signal I 3  and the fourth imaging signal I 4 . 
     Moreover, although the sums of absolute difference such as Equations (4) and (59) are used as the parallax evaluation value Ri(k) in Embodiments 1 to 5, there is no limitation to this. For example, it also is possible to use the sum of the square of differences, the sum of the square of differences between a value obtained by subtracting an average in a block from the first imaging signal I 1  and a value obtained by subtracting the average in the block from the fourth imaging signal I 4 , or a value obtained by dividing the sum of the square of differences between a value obtained by subtracting an average in a block from the first imaging signal I 1  and a value obtained by subtracting the average in the block from the fourth imaging signal I 4  by the square root of the sum of the square of the value obtained by subtracting the average in the block from the first imaging signal I 1  and further by the square root of the sum of the square of the value obtained by subtracting the average in the block from the fourth imaging signal I 4 . 
     As the parallax evaluation value Ri(k), it also may be possible to use Equation (60) or the sum of results of multiplication of a difference between the first imaging signal I 1  and the average in the block and a difference between the fourth imaging signal I 4  and the average in the block. However, since the parallax evaluation value Ri(k) in Embodiments 1 to 5 decreases with an increase in the correlation (similarity), k giving the minimum value gives the parallax Δi as shown in  FIG. 15 . However, when using Equation (60) or the like, the value increases with an increase in the correlation (similarity), thus making it necessary to make suitable modifications such as using k giving the maximum value as the parallax Δi. 
     Also, in Embodiments 1 to 5, the first lens portion  113   a , the second lens portion  113   b , the third lens portion  113   c  and the fourth lens portion  113   d  are arranged so that a rectangle formed by connecting the centers of their optical axes is a square. However, there is no limitation to this. This rectangle also may have sides with different lengths in the x and y directions. In this case, suitable modifications are necessary, for example, when the parallax is computed in Steps S 140  and S 3240  and when the parallax correction is performed in Steps S 151 , S 184 , S 250  and S 3280 . In other words, instead of using the same k for the x and y directions, k is changed so as to maintain the ratio between the lengths of the sides in the x and y directions of the above-mentioned rectangle. 
     Further, although the parallax is computed as an integer in Embodiments 1 to 5, there is no limitation to this. It also may be possible to compute the parallax to decimal places by a linear interpolation in Steps S 140 , S 240  and S 3240  and correct the respective parallax utilizing the linear interpolation in Steps S 184 , S 250  and S 3280 . 
     Moreover, in Embodiments 1 to 5, it also may be possible to carry out the block division and the parallax correction while omitting the focusing control and including no actuator in the configuration. In the case of using a lens with a very large depth of focus, a slight error in the distance between the lens and the imaging device can be tolerated to a great extent. Thus, there is no need to operate the actuator. 
     Furthermore, in Embodiments 1 to 5, the first imaging signal I 1  mainly indicates a green component, the second imaging signal I 2  mainly indicates a blue component, the third imaging signal I 3  mainly indicates a red component, the fourth imaging signal I 4  mainly indicates a green component, and the parallax is sensed by comparing the first imaging signal I 1  and the fourth imaging signal I 4 , thus carrying out the parallax correction. However, there is no limitation to this. For example, the designs of the lens and the color filters may be modified so that the first imaging signal I 1  mainly indicates a green component, the second imaging signal I 2  mainly indicates a green component, the third imaging signal I 3  mainly indicates a blue component and the fourth imaging signal I 4  mainly indicates a red component. In this case, it is necessary to modify the parallax evaluation function as per Equation (87) below so as to perform the parallax correction as per Equations (88), (89) and (90) below.
 
 Ri ( k )=ΣΣ| I 1( x,y )− I 2( x−k,y )|  (87)
 
 G ( x,y )=[ I 1( x,y )+ I 2( x−Δi,y )]/2  (88)
 
 B ( x,y )= I 3( x,y−Δi )  (89)
 
R(x,y)−I4(x−Δi,y−Δi)  (90)
 
     It also may be possible to make modifications so that the first imaging signal I 1  mainly indicates a green component, the second imaging signal I 2  mainly indicates a blue component, the third imaging signal I 3  mainly indicates a green component and the fourth imaging signal I 4  mainly indicates a red component. In this case, it is necessary to modify the parallax evaluation function as per Equation (91) below so as to perform the parallax correction as per Equations (92), (93) and (94) below.
 
 Ri ( k )=ΣΣ| I 1( x,y )− I 3( x,y−k )  (91)
 
 G ( x,y )=[ I 1( x,y )+ I 3( x,y−Δi )]/2  (92)
 
 B ( x,y )= I 2( x−Δi,y )  (93)
 
 R ( x,y )= I 4( x−Δi,y−Δi )  (94)
 
     Further, although the four imaging regions are provided in a lattice pattern in Embodiments 1 to 5, there is no limitation to this. For example, modifications may be made so that the first to fourth imaging devices are aligned along a straight line, the first imaging signal I 1  mainly indicates blue, the second imaging signal I 2  mainly indicates green, the third imaging signal I 3  mainly indicates green and the fourth imaging signal I 4  mainly indicates red. In this case, it is necessary to modify the parallax evaluation function as per Equation (95) below so as to perform the parallax correction as per Equations (96), (97) and (98) below.
 
 Ri ( k )=| I 2( x,y )− I 3( x−k,y )|  (95)
 
 G ( x,y )=[ I 2( x,y )+ I 3( x−Δi,y )]/2  (96)
 
 B ( x,y )= I 1( x+Δi,y )  (97)
 
 R ( x,y )= I 4( x− 2 *Δi,y )  (98)
 
     Further, although the four imaging regions are provided in Embodiments 1 to 5, there is no limitation to this. For example, modifications may be made so that three imaging regions are provided, the first to third imaging devices are aligned along a straight line, the first imaging signal I 1  mainly indicates blue, the second imaging signal I 2  mainly indicates green and the third imaging signal I 3  mainly indicates red. In this case, it is necessary to modify the parallax evaluation function as per Equations (99) and (100) below, create a green component G as per Equation (101) below, create a blue component B as per Equation (102) below by utilizing the parallax Δi computed using Equation (99) and create a red component R as per Equation (103) below by utilizing the parallax Δi computed using Equation (100) so as to perform the parallax correction. In addition, Equation (60) may be used instead of Equations (99) and (100).
 
 Ri ( k )=ΣΣ| I 2( x,y )− I 1( x+k,y )  (99)
 
 Ri ( k )=ΣΣ| I 2( x,y )− I 3( x−k,y )|  (100)
 
 G ( x,y )= I 2( x,y )  (101)
 
 B ( x,y )= I 1( x+Δi,y )  (102)
 
 R ( x,y )= I 3( x−*Δi,y )  (103)
 
     Alternatively, modifications may be made so that three imaging regions are provided, the second imaging device is arranged to the right of (at a position positive in the x axis with respect to) the first imaging device, the third imaging device is arranged below (at a position positive in the y axis with respect to) the first imaging device, the first imaging signal I 1  mainly indicates green, the second imaging signal I 2  mainly indicates blue and the third imaging signal I 3  mainly indicates red. In this case, it is necessary to modify the parallax evaluation function as per Equations (104) and (105) below, create a green component G as per Equation (106) below, create a blue component B as per Equation (107) below by utilizing the parallax Δi computed using Equation (104) and create a red component R as per Equation (108) below by utilizing the parallax Δi computed using Equation (105) so as to perform the parallax correction. In addition, Equation (60) may be used instead of Equations (104) and (105).
 
 Ri ( k )=ΣΣ| I 1( x,y )− I 1( x−k,y )|  (104)
 
 Ri ( k )=ΣΣ I 1( x,y )− I 3( x,y−k )|  (105)
 
 G ( x,y )= I 1( x,y )  (106)
 
 B ( x,y )= I 2( x−Δi,y )  (107)
 
 R ( x,y )= I 3( x,y−Δi )  (108)
 
     In the camera module according to Embodiment 1, Embodiments 3 to 5, the parallax correction is performed using the parallax Δi in the block. However, it also may be possible to determine a parallax Δ(x,y) for each pixel using the parallax Δi for each block and perform the parallax correction using this parallax Δ(x,y) for each pixel. 
     INDUSTRIAL APPLICABILITY 
     The camera module according to the present invention is a camera module that can be made smaller and thinner and has an automatic focusing function, and therefore, is useful for a mobile phone with a camera function, a digital still camera, a vehicle-mounted camera, a surveillance camera and the like.