Abstract:
An image pickup apparatus comprising plural image taking systems for taking the image of an object and outputting image signals, a memory circuit for storing plural image signals output from the plural image pickup systems, a convergence angle setting unit for setting the convergence angle of the plural image pickup systems, and a trimming circuit for extracting, from each of the plural image signals stored in the memory circuit, the signal of a portion corresponding to the convergence angle set by the convergence angle setting unit.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a plural-eye image pickup apparatus, for taking the image of an object with plural image pickup systems thereby achieving stereoscopic view and input of distance information. 
     2. Related Background Art 
     In the plural-eye image pickup apparatus for providing a stereoscopic image by taking the image of an object with plural image pickup systems, it is already known to adjust the stereoscopic perception by controlling the convergence angle of the image taking systems. 
     In such apparatus, the adjustment of the convergence angle is generally achieved by activating a motor or the like provided in each image pickup system. 
     Also in taking the stereoscopic image, the vibration of the holding hand, for example, deteriorates the precision of stereoscopic image synthesis for stereoscopic viewing, thereby resulting in instability in the image synthesis or fatigue of the observer caused by the image involving vibration, but the reduction of such drawbacks has not been given much consideration in the past. 
     The conventional image pickup apparatus mentioned above requires certain mechanisms for controlling the convergence angle, and the apparatus inevitably becomes complex and bulky for this reason. 
     Also the mechanical play or the like in the control of the convergence angle results in an aberration between the images obtained by the respective image pickup systems, leading to an inconvenience in the stereoscopic viewing. 
     Furthermore, in case of a hand-held plural-eye image pickup apparatus, the vibration of the holding hand at image taking causes a vibration in the taken image, thus increasing the fatigue of the person observing the stereoscopic image. 
     Furthermore, in a plural-eye image pickup apparatus employing a zoom lens, the zooming operation causes a shift in the optical axis, causing a parallax inappropriate for the stereoscopic observation and inducing fatigue of the observer. 
     SUMMARY OF THE INVENTION 
     In consideration of the foregoing, a first object of the present invention is to provide a plural-eye image pickup apparatus capable of achieving compactization of the apparatus, also eliminating play or the like in the mechanical control, and suppressing the fatigue in stereoscopic observation, resulting from the vibration in the image caused by the shaking of the holding hand, thereby always providing an image of high quality. 
     The above-mentioned object can be attained, according to a preferred embodiment of the present invention, by a plural-eye image pickup apparatus comprising plural image pickup systems for respectively taking the images of an object thereby providing image signals; a memory circuit for storing the plural image signals released from said plural imaging pickup systems; a convergence angle setting device for setting the convergence angle of said plural image taking systems; and a trimming circuit for respectively extracting, from the plural image signals stored in said memory circuit, signals of portions corresponding to the convergence angle set by said convergence angle setting device. 
     There is thus disclosed a configuration which effects electrical control of the convergence angle, in obtaining the images of the object with plural image pickup systems for the purpose of stereoscopic viewing or entry of the distance information. 
     A second object of the present invention is to provide a plural-eye image pickup apparatus capable, in taking the images of the object with plural image pickup optical system for the purpose of stereoscopic viewing or entry of distance information, of correcting the difference in phase between the images obtained by the respective image pickup optical systems, thereby suppressing the fatigue in stereoscopic viewing and facilitating the processing in the entry of distance information. 
     Also a third object of the present invention is to present deterioration of the image resulting from mechanical perturbation, thereby providing a stereoscopic image of high quality. 
     Still other objects of the present invention, and the features thereof, will become fully apparent from the following description, which is to be taken in conjunction with the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram showing a first embodiment of the present invention; 
     FIG. 2 is a schematic view, showing the outline of the convergence angle control; 
     FIGS. 3A to 3C are views showing the outline of a matching method; 
     FIG. 4 is a schematic view showing the outline of correction of vibration; 
     FIG. 5 is a schematic view showing the outline of convergence angle control by trimming; 
     FIG. 6 is a schematic view showing the outline of the process by a trimming area setting unit; 
     FIG. 7 is a block diagram showing a second embodiment of the present invention; 
     FIG. 8 is a schematic view showing the outline of the image signal to be trimmed; 
     FIG. 9 is a schematic view showing the outline of the process of a phase difference detection unit; 
     FIGS. 10A and 10B are schematic views showing the outline of a phase correcting method; and 
     FIG. 11 is a schematic view showing the outline of the image signal to be trimmed. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Now the image pickup apparatus of the present invention will be clarified in detail by preferred embodiments thereof, with reference to the attached drawings. 
     FIG. 1 is a block diagram showing a first embodiment of the present invention. 
     In FIG. 1, there are shown optical axes 1R, 1L of right and left image pickup systems; right and left image pickup lenses 100R, 100L; and CCDs 101R, 101L serving as image pickup elements for converting the optical images of an object into electrical signals, with a number of pixels larger than that used ordinarily for the NTSC standard. The image pickup elements are naturally not limited to the CCDs but can be of those of any other type. 
     A/D converters 102R, 102L convert the analog electrical signals, obtained from the CCDs 100R, 100L into digital signals. 
     103R, 103L are digital signal processors (DSP) and process the A/D converted electrical signals to generate suitable image signals. 
     Image memories 104R, 104L temporarily store the image signals generated by the DSPs 103R, 103L. 
     D/A converters 105R, 105L convert the digital image signals, read from the memories 104R, 104L, into analog image signals. 
     Motion detection units 106R, 106L detect the amount of motion between the fields (or frames) of the images respectively taken by the CCDs 101R, 101L. More specifically, motion vectors are determined by memorizing a feature image in a predetermined area in a field and effecting matching calculation with the image of a next field. 
     Trimming area setting units 107R, 107L control the write-in and read-out addresses of the memories 104R, 104L. 
     A microcomputer 110 controls the entire image pickup apparatus. 
     A convergence angle setting unit 120 sets the convergence angle of the image pickup systems at the image pickup operation. An image synthesis circuit 150 generates a stereoscopic image by synthesizing the left and right image signals output from the D/A converters 105R, 105L, and a display 160 displays the stereoscopic image. 
     FIG. 2 shows the working principle of the plural-eye image pickup apparatus of the present invention, wherein 201R, 201R&#39;, 201L, 201L&#39; indicate trimming areas, taken with the ordinary aspect ratio of 4:3, on the image pickup planes of the CCDs 101R, 101L. The trimming areas 201R, 201L correspond to the optical axes 1R, 1L, while those 201R&#39;, 201L&#39; correspond to the optical axes 1R&#39;, 1L&#39;. 
     In the present invention, the convergence angle is controlled by trimming the images taken by the CCDs 101R, 101L. More specifically, the control of the convergence angle is achieved by shifting the center positions of the trimming areas 201R, 201L to obtain the trimming areas 201R&#39;, 201L&#39; where the optical axes 1R, 1L are practically shifted to 1R&#39;, 1L&#39;. 
     Consequently the control of the convergence angle can be achieved electrically and does not require a mechanism therefor, and there can be avoided the image deterioration or the error resulting from mechanical errors. 
     In the following there will be given an explanation on the function of the apparatus of the present invention. 
     Optical images of the object, obtained through the image pickup lenses 100R, 100L, are focused on the image pickup planes of the CCDs 101R, 101L and are converted into analog electrical image signals. These image signals are converted by the A/D converters 102R, 102L into digital image signals, which are then supplied to the DSPs 103R, 103L. 
     The DSPs 103R, 103L effect digital signal processing to generate suitable image signals, which are supplied to the memories 104R, 104L and to the motion detection units 106R, 106L. 
     The motion detection units 106R, 106L detect the motion vectors between the image of the current field and that of the preceding field, with the principle shown in FIGS. 3A to 3C. 
     As shown in FIG. 3A, the image signal of the current field is divided, within the image area, into plural blocks of a suitable size. The image signal of each divided block is subjected to template matching with the image signal of the preceding field as shown in FIG. 3B, and there is determined a position where the correlation becomes highest. The motion vectors of the blocks can be determined as shown in FIG. 3C, by effecting the above-mentioned process to each block. 
     The motion detection units 106R, 106L unify the motion vectors of the blocks, then determine a representative value (x, y) of the motion vectors of the current field, from the average and center value of these motion vectors, and sends this representative value to the trimming area setting units 107R, 107L. 
     FIG. 4 shows, as an example, the image signal of the current field stored in the memory 104R. 
     As the CCDs employed in the present embodiment are of a large area with a number of pixels larger than that ordinarily employed for the NTSC standard, it is possible to trim, from the image signal, a broken-lined area with an aspect ratio 4:3 as shown in FIG. 4, according to the representative value (x, y) of the motion vectors. 
     The convergence angle input unit 120 is provided with a dial or buttons, of which manipulation shifts the optical axes 1R, 1L from the parallel state shown in FIG. 2 to an inwardly converging state indicated by 1R&#39;, 1L&#39;. 
     Upon receiving information on the change of the convergence angle from the convergence angle input unit 120, the microcomputer 110 provides the trimming area setting units 107R, 107L with a control signal. 
     FIG. 5 shows the outline of the change of the convergence angle by trimming, in case of a shift to the inward convergence as shown in FIG. 2. Based on the information from the convergence angle input unit 120, the microcomputer 110 provides the trimming area setting units 107R, 107L with an image shift amount Δx. In FIG. 5, the trimming areas are indicated by broken lines and chain lines. 
     The trimming area setting units 107R, 107L determines a final trimming area, based on the motion vector (x, y) from the motion detection units 106R, 106L and the convergence angle shift amount Δx from the microcomputer 110. 
     FIG. 6 shows, as an example, a trimming area obtained in the trimming area setting units 107R, 107L by combining the motion vectors and the convergence angle shift amount. The same process is also conducted in the trimming area setting unit 107L. 
     In FIG. 6, the motion vector (x, y) represents image displacement caused by motion detected by the motion detection units 106R. A reference numeral 601 denotes a trimming area of the current field, which determined by only the motion vector detected by the motion detection unit 106. Δx is shift amount for change of the convergence angle by trimming. The trimming area setting unit 107R further shifts the trimming area 601 determined by the motion vector, by Δx to set a trimming area 602 which is provided by synthesizing the motion vector (x, y) and the shift amount Δx. 
     Then, based on the control signals obtained from the trimming area setting units 107R, 107L, parts of the images are read with trimming from the memories 104R, 104L and are supplied to the D/A converters 105R, 105L, which convert the digital image signals from the memories 104R, 104L into analog signals for output. 
     In this manner there can be obtained an image of high quality, corrected for the hand vibration, without relying on the complex mechanism for the convergence angle control. 
     The output signals of these D/A converters 105R, 105L are supplied to the image synthesis circuit 160 to enable stereoscopic viewing. 
     FIG. 7 is a block diagram of a second embodiment of the present invention, wherein components equivalent in function to those in the first embodiment are represented by same numbers and will not be explained further. 
     This embodiment is different from the first one in the use of zoom lenses 108R, 108L for the image pickup lenses and in the presence of a phase difference detection unit 130. 
     The phase difference detection unit 130 detects the phase difference of overlapping areas in the image signals of the memories 104R, 104L and sends a detection signal to the trimming area setting units 107R, 107L. 
     In case of image taking with zoom optical systems as in the apparatus of the present embodiment, a zooming operation results in a shift of the optical axes, thus generating an aberration in the registration between the images obtained by the respective image taking systems. 
     FIG. 8 schematically shows the image signals in the memories 104R, 104L and the trimming area based on the motion vectors and the convergence angle control. 
     In case of effecting the correction for the vibration and the convergence angle control independently for each image signal as shown in FIG. 8, the phases of the images do not necessarily coincide mutually. 
     FIG. 9 shows, in superposed manner, the trimming areas for the memories 104R, 104L shown in FIG. 8, wherein V1 and V2 are phase difference vectors to be explained later. 
     As will be apparent in FIG. 9, the images are mutually aberrated, and particularly the aberration in the vertical direction has to be corrected as it increases the fatigue in the stereoscopic observation. 
     The phase difference detection unit 130 receives, from the memories 104R, 104L, the image signals of the trimming areas determined from the motion vectors and the convergence angle control signal, and detects the phase differences in the vertical and horizontal directions, utilizing calculation of correlation or template matching on thus entered image signals. 
     FIG. 9 shows the vectors V1, V2, representing the detected phase differences. The phase difference may be determined for each pixel or for each of suitable blocks. 
     Then the phase difference detection unit 130 sets, based on thus determined phase difference, trimming areas so as to match the phase in the vertical direction as shown in FIGS. 10A and 10B, and sends control signals to the trimming area setting unit 107R, 107L. 
     FIG. 11 shows the outline of the phase difference correction, wherein 300R and 300L indicate the trimming areas obtained in consideration of the phase difference between the images. 
     The image signals of the trimming areas 300R, 300L are converted in the D/A converters 105R, 105L and released. 
     As explained in the foregoing, these embodiments enable the control of the convergence angle in electrical manner, without employing a mechanism such as motors. Thus the apparatus can be made smaller, and there can avoided the aberration of the images resulting from the mechanical errors, thereby realizing satisfactory stereoscopic viewing. 
     Also the foregoing embodiments allow to eliminate the vibration in images, resulting from the vibration of the hands holding the image pickup systems, thereby reducing the fatigue in the stereoscopic image viewing. 
     Furthermore, in case of using zoom lenses, the foregoing embodiments allow to eliminate the undesirable parallax, such as the vertical parallax based on the aberration of the optical axes in zooming operation, thereby reducing the fatigue in the stereoscopic viewing and alleviating the load of processing.