Patent Publication Number: US-2012027393-A1

Title: Electronic equipment

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This nonprovisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2010-168699 filed in Japan on Jul. 27, 2010, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electronic equipment such as a digital camera. 
     2. Description of Related Art 
     There is proposed a function of adjusting an in-focus state of a target image by image processing, and a type of processing for realizing this function is also called a digital focus. The in-focus state of the target image means, for example, a depth of field of the target image or an in-focus distance of the target image (e.g., a center of the depth of field). 
     As a method of determining the in-focus state, there are considered a complete automatic setting method, a method of designating a subject by a user, and a complete manual setting method. 
     In the complete automatic setting method, the digital camera automatically performs detection of a main subject and setting of an in-focus distance and a depth of field adapted to the main subject. 
     In the method of designating a subject by a user, the user selects and designates a subject to be focused using a touch panel or the like, and the digital camera sets the in-focus distance and the depth of field in accordance with the designation. 
     In the complete manual setting method, a user manually inputs all the in-focus distance and the depth of field. 
     However, in the complete automatic setting method, as illustrated in FIG.  18 A, an actual in-focus distance and an actual depth of field may be largely different from the in-focus distance and the depth of field desired by the user. 
     In addition, in the method of designating a subject by a user, a result image that substantially meets the user&#39;s intention can be obtained, but fine adjustment of the in-focus state is difficult. For instance, in a result image obtained as illustrated in  FIG. 18B , not only a designated subject  911  but also a subject  912  positioned in the vicinity of the designated subject  911  is focused by the digital focus. However, the user may want a shallow depth of field in which only the designated subject  911  is focused. In this case, a fine adjustment of the in-focus distance and/or the depth of field is necessary. However, according to the method of determining the in-focus distance and the depth of field according to only the designated content of the subject, such fine adjustment is difficult. 
     On the other hand, in the complete manual setting method, the in-focus distance and the depth of field can be designated as the user wants. In this case, the digital camera cannot recognize a user&#39;s intention unless the user performs an input operation. Therefore, as illustrated in  FIG. 18C , for example, a distance range from a position  921  near the digital camera to a position  922  corresponding to the point at infinity is divided into steps at a constant interval, and an instruction to adjust the in-focus distance and the depth of field per step is accepted. For instance, if a desired in-focus distance is positioned on the long distant side of the current designated in-focus distance by 30 steps, it is necessary to perform a unit operation of moving the designated in-focus distance to the long distant side 30 times. A load of such an operation is large, and a simpler operation method is expected to be proposed. In this case, it is needless to say that it is desirable to realize a method satisfying a user&#39;s intention. 
     SUMMARY OF THE INVENTION 
     Electronic equipment according to an aspect of the present invention includes a digital focus portion that adjusts an in-focus state of a target image by image processing, and a unit adjustment amount setting portion that sets a unit adjustment amount in adjustment of the in-focus state based on distance information of the target image. 
     Electronic equipment according to another aspect of the present invention includes a digital focus portion that adjusts an in-focus state of a target image including a depth of field of the target image by image processing, and a unit adjustment amount setting portion that sets a unit adjustment amount in adjustment of the depth of field based on an in-focus distance as a reference distance in the depth of field. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic general block diagram of an imaging apparatus according to a first embodiment of the present invention. 
         FIG. 2  is an internal structural diagram of an imaging portion illustrated in  FIG. 1 . 
         FIG. 3  is a block diagram of a part that is particularly related to digital focus according to the first embodiment of the present invention. 
         FIG. 4  is a diagram illustrating a positional relationship between the imaging apparatus and a plurality of subjects supposed in the first embodiment of the present invention. 
         FIGS. 5A and 5B  are diagrams illustrating examples of a target input image and a target output image, respectively, according to the first embodiment of the present invention. 
         FIG. 6  is a diagram illustrating a distance distribution of a subject distance according to the first embodiment of the present invention. 
         FIG. 7  is a diagram illustrating a classification of a subject presence distance range and a subject absence distance range based on a distance distribution of the subject distance according to the first embodiment of the present invention. 
         FIG. 8  is a diagram illustrating a plurality of step positions set based on the distance distribution of the subject distance according to the first embodiment of the present invention. 
         FIG. 9  is a diagram illustrating a width between neighboring step positions according to the first embodiment of the present invention. 
         FIG. 10  is a diagram illustrating an outline of a setting method of a unit adjustment amount according to the first embodiment of the present invention. 
         FIG. 11  is a modified block diagram of the part that is particularly related to the digital focus according to the first embodiment of the present invention. 
         FIG. 12  is a flowchart of an operation of generating the target output image from the target input image according to the first embodiment of the present invention. 
         FIG. 13  is a diagram illustrating four buttons that can be disposed in the operating portion according to the first embodiment of the present invention. 
         FIG. 14  is a diagram illustrating an example of a display screen during the adjustment of the in-focus state according to the first embodiment of the present invention. 
         FIG. 15  is a diagram illustrating an example of a display screen during the adjustment of the in-focus state according to the first embodiment of the present invention. 
         FIG. 16  is a diagram illustrating a classification of a fine adjustment range and a rough adjustment range based on an in-focus distance according to the second embodiment of the present invention. 
         FIG. 17  is a diagram illustrating a width between neighboring step positions according to the second embodiment of the present invention. 
         FIGS. 18A to 18C  are diagrams illustrating conventional methods for adjusting the in-focus state. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, examples of embodiments of the present invention are described in detail with reference to the attached drawings. In the diagrams that are referred to, the same portion is denoted by the same numeral or symbol, and overlapping description of the same portion is omitted as a rule. 
     First Embodiment 
     A first embodiment of the present invention is described.  FIG. 1  is a schematic general block diagram of an imaging apparatus  1  according to the first embodiment. The imaging apparatus  1  is a digital still camera that can take and record still images, or a digital video camera that can take and record still images and moving images. The imaging apparatus  1  may be one incorporated in a mobile terminal such as a mobile phone. 
     The imaging apparatus  1  includes an imaging portion  11 , an AFE  12 , an image processing portion  13 , a microphone portion  14 , a sound signal processing portion  15 , a display portion  16 , a speaker portion  17 , an operating portion  18 , a recording medium  19 , and a main control portion  20 . 
       FIG. 2  illustrates an internal structural diagram of the imaging portion  11 . The imaging portion  11  includes an optical system  35 , an aperture stop  32 , an image sensor  33  constituted of a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) image sensor, and a driver  34  that drives and controls the optical system  35  and the aperture stop  32 . The optical system  35  is constituted of a plurality of lenses including a zoom lens  30  and a focus lens  31 . The zoom lens  30  and the focus lens  31  can move in the optical axis direction. The driver  34  drives and controls positions of the zoom lens  30  and the focus lens  31 , and an aperture of the aperture stop  32  based on control signals from the main control portion  20 , so as to control a focal length (an angle of view) of the imaging portion  11 , a focal position of the same, and an incident light amount to the image sensor  33  (i.e., an aperture stop value). 
     The image sensor  33  performs photoelectric conversion of an optical image expressing a subject, which has entered through the optical system  35  and the aperture stop  32  and output an electric signal obtained by the photoelectric conversion to the AFE  12 . The AFE  12  amplifies an analog signal output from the imaging portion  11  (image sensor  33 ) and converts the amplified analog signal into a digital signal. The AFE  12  outputs the digital signal as RAW data to the image processing portion  13 . An amplification degree of the signal amplification in the AFE  12  is controlled by the main control portion  20 . 
     The image processing portion  13  generates image data expressing an image taken by the imaging portion  11  (hereinafter referred to also as a taken image) based on the RAW data from the AFE  12 . The image data generated here contains, for example, a luminance signal and a color difference signal. However, the RAW data is also one type of the image data, and the analog signal output from the imaging portion  11  is also one type of the image data. 
     The microphone portion  14  converts ambient sound around the imaging apparatus  1  into a sound signal and output the result. The sound signal processing portion  15  performs necessary sound signal processing on the output sound signal of the microphone portion  14 . 
     The display portion  16  is a display device having a display screen such as a liquid crystal display panel, and displays a taken image or an image recorded in the recording medium  19  under control of the main control portion  20 . The display and the display screen in the following description mean the display and the display screen of the display portion  16  unless otherwise noted. The speaker portion  17  is constituted of one or more speakers, which reproduce and output sounds of various sound signals such as a sound signal generated by the sound signal processing portion  15  and a sound signal read out from the recording medium  19 . The operating portion  18  is a part that receives various operations from a user. An operation content of the operating portion  18  is transmitted to the main control portion  20  and the like. The recording medium  19  is a nonvolatile memory such as a card-like semiconductor memory or a magnetic disk, which records the taken image and the like under control of the main control portion  20 . The main control portion  20  integrally controls operations of the individual parts in the imaging apparatus  1  in accordance with operation content of the operating portion  18 . 
     Operation modes of the imaging apparatus  1  includes an imaging mode in which a still image or a moving image can be taken, and a reproduction mode in which a still image or a moving image recorded in the recording medium  19  can be reproduced on the display portion  16 . In the imaging mode, images of the subject are periodically taken at a predetermined frame period, and the imaging portion  11  (more specifically, the AFE  12 ) outputs the RAW data expressing a series of taken images of the subject. A series of images such as a series of taken images means a set of images arranged in time series. The image data of one frame period expresses one image. One taken image expressed by the image data of one frame period from the AFE  12  is referred to also as a frame image. It can be interpreted that the frame image is an image obtained by performing a predetermined image processing (a demosaicing process, a noise reduction process, a color correction process, or the like) on the taken image of the RAW data. 
     The imaging apparatus  1  has a function of adjusting the in-focus state of the target input image by image processing after obtaining the image data of the target input image. The process of realizing this function is referred to as a digital focus. The digital focus can be performed in the reproduction mode. The target input image is a frame image obtained as a still image or a frame image constituting a moving image.  FIG. 3  illustrates a block diagram of a part that is particularly related to the digital focus. Individual parts denoted by numerals  51  to  55  can be disposed in the imaging apparatus  1 . For instance, an adjustment map generating portion  52  including a unit adjustment amount generating portion  53  and an in-focus distance and depth of field designation portion  54  can be disposed in the main control portion  20  illustrated in  FIG. 1 , and an digital focus portion  55  can be disposed in the image processing portion  13  illustrated in  FIG. 1 . 
     The target input image after the adjustment of the in-focus state by the digital focus is referred to as a target output image. The in-focus state to be adjusted by the digital focus includes the in-focus distance of the target input image and a depth value of the depth of field of the target input image. 
     The in-focus distance of the target image as the target input image or the target output image is a reference distance in the depth of field of the target image, and is typically a distance at a center in the depth of field of the target image, for example. As known well, subjects having subject distances within the depth of field are focused in the target image. When the in-focus state of the target input image is adjusted by the digital focus, if the user performs the unit operation one time, the in-focus state of the target input image is changed by the unit adjustment amount. For instance, if the user performs the unit operation one time, the in-focus distance is increased or decreased by the unit adjustment amount, or the depth of field is increased or decreased by the unit adjustment amount. In other words, the unit adjustment amount indicates an adjustment amount of the in-focus distance or the depth of field by the unit operation (per unit operation). The unit adjustment amount and the adjustment amount can be read as a unit change amount and a change amount, respectively. In the first embodiment, the unit adjustment amount is set by using subject distance information. Hereinafter, operations of individual parts illustrated in  FIG. 3  are described in detail. 
     The subject distance information generating portion  51  detects subject distances of subjects within an imaging range of the imaging portion  11 , so as to generate subject distance information indicating subject distances of subjects at positions on the target input image. The subject distance of the subject means a distance in real space between the subject and the imaging apparatus  1  (more specifically the image sensor  33 ). The image sensor  33  that takes the target input image corresponds to an view point of the target input image. Therefore, the subject distance information of the target input image is information indicating a distance between the subject of each position on the target input image and the view point of the target input image (i.e., information indicating a distance between the subject at each position on the target input image and the imaging apparatus  1  as an apparatus used for taking the target input image). Note that in this specification, the expression that the distance is large and the expression that the distance is long have the same meaning, while the expression that the distance is small and the expression that the distance is short have the same meaning. The subject distance information is a distance image (in other words, range image) of which each pixel value has a measured value (i.e., a detected value) of the subject distance. As a method of detecting the subject distance and a method of generating the subject distance information, any known method (e.g., a method described in JP-A-2009-272799) can be used. 
     It is possible to generate the subject distance information from image data of the target input image or to generate subject distance information from information other than the image data of the target input image. For instance, it is possible to generate the subject distance information using a distance measuring sensor (not shown) for measuring subject distance of the subject at each position on the target input image. As the distance measuring sensor, any known distance measuring sensor such as a distance measuring sensor based on triangulation can be used. Alternatively, for example, a compound eye camera may be used for generating the distance image. Alternatively, for example, a contrast detection method may be used. In this case, for example, a position of the focus lens  31  is moved step by step by a predetermined amount while image data are obtained sequentially from the AFE  12 . The distance image can be generated from high frequency components of spatial frequency components of the obtained image data. 
     Alternatively, for example, the imaging portion  11  may be formed so that the RAW data contains information indicating the subject distance, and the subject distance information may be generated from the RAW data. In order to realize this, for example, a method called “Light Field Photography” (e.g., a method described in WO/06/039486 Pamphlet or JP-A-2009-224982, hereinafter, referred to as a light field method) may be used. In the light field method, an imaging lens having an aperture stop and a micro lens array are used so that the image signal obtained from the image sensor also contains light propagation direction information in addition to light intensity distribution on a light receiving surface of the image sensor. Therefore, although not illustrated in  FIG. 2 , optical members necessary for realizing the light field method are disposed in the imaging portion  11  if the light field method is used. The optical members include a micro lens array and the like, and hence incident light from the subject enters the light receiving surface (i.e., an imaging surface) of the image sensor  33  via the micro lens array and the like. The micro lens array is constituted of a plurality of micro lenses, and one micro lens is assigned to one or more light receiving pixels of the image sensor  33 . Thus, an output signal of the image sensor  33  also contains information of incident light propagation direction to the image sensor  33  in addition to the light intensity distribution on the light receiving surface of the image sensor  33 . 
     A generation timing of the subject distance information is arbitrary. For instance, it is possible to generate the subject distance information when the target input image is taken or just after taking the same. In this case, the image data of the target input image and the subject distance information are associated with each other and are recorded in the recording medium  19 . Then, before performing the digital focus, the image data of the target input image together with the subject distance information are read out from the recording medium  19 . Alternatively, for example, it is possible to generate the subject distance information just before the digital focus is performed. In this case, after the target input image is taken, the image data of the target input image and information to be a base of the subject distance information are associated with each other and are recorded in the recording medium  19 . When the digital focus is performed, the image data of the target input image and the information to be a base of the subject distance information are read out from the recording medium  19 . Then, the subject distance information is generated from the read information. Note that as understood from the above-mentioned description, the information to be a base of the subject distance information can be the same as the image data of the target input image or can include the image data of the target input image. 
     As illustrated in  FIG. 4 , it is supposed that the target input image is taken in the state where a subject  301  that is a person and a subject  302  that is a tree are included in the imaging range of the imaging portion  11 . The subject  301  is supposed to be one or more persons, and in the example of  FIG. 4 , two persons form the subject  301 . The subject  302  is one or more trees, and the subject  302  is constituted of two trees in the example illustrated in  FIG. 4 . The subject distances of the subject  301  are distributed around a distance d 301  as the center, and the subject distances of the subject  302  are distributed around a distance d 302  as the center. It is supposed that the subject  301  is a subject on the short distance side, and that the subject  302  is a subject on the long distance side. Therefore, “0&lt;d 301 &lt;d 302 ” is satisfied. 
     An image  300  illustrated in  FIG. 5A  is an example of a target input image taken in the state where the subjects  301  and  302  are included in the imaging range of the imaging portion  11 . In the target input image  300  illustrated in  FIG. 5A , a whole or a part of the subject  301  is in focus, while the subject  302  is not in focus. In  FIG. 5A , contour lines of objects in the target input image  300  are thickened so as to express blur of the image (the same is true in  FIG. 5B  and the like that will later be referred to). For instance, if the in-focus distance of the target input image  300  is changed to a subject distance d 302  by the digital focus, a target output image  310  as illustrated in  FIG. 5B  is obtained. In the following description, for specific description, a case in which the target input image  300  of  FIG. 5A  is obtained as the target input image is supposed as an example. Note that, for convenience sake of description, it is supposed that any subject other than the subjects  301  and  302  did not exist in the imaging range of the imaging portion  11  when the target input image  300  was taken. 
       FIG. 6  illustrates a distance distribution  320  based on subject distance information of the target input image  300 . As described above, the subject distance information is a distance image of which each pixel value has a measured value of the subject distance. A histogram as a graph of a distribution of pixel values in the distance image is the distance distribution  320 . 
     When the distance distribution  320  is formed, each pixel value (i.e., subject distance) in the distance image is classified in one of classes, and each class width of the distance distribution  320  can be a predetermined distance width (e.g., a few centimeters to a few ten centimeters). The i-th class forming the distance distribution  320  is expressed by C[i] (see  FIG. 7  too). The symbol i denotes an integer. It is supposed that a distance belonging to a class C[i+1] is larger than a distance belonging to a class C[i], and any two different classes do not overlap each other. For instance, subject distances larger than or equal to 1.0 meter and smaller than 1.2 meters belong to the class C[i], subject distances larger than or equal to 1.2 meters and smaller than 1.4 meters belong to the class C[i+1], and subject distances larger than or equal to 1.4 meters and smaller than 1.6 meters belong to a class C[i+2]. The class width may be different between different classes. As illustrated in  FIG. 6 , in the distance distribution  320 , most of frequencies are concentrated on a portion around the distance d 301  and a portion around the distance d 302 . 
     It is supposed that frequencies of a predetermined threshold value F TH  or larger belong only to each of the classes C[ 10 ] to C[ 15 ] and C[ 50 ] to C[ 55 ] among all the classes of the distance distribution  320  (F TH  denotes a natural number). A class to which frequencies of the threshold value F TH  or larger belong is referred to as a subject presence class, while a class to which frequencies of the threshold value F TH  or larger do not belong is referred to as a subject absence class. Therefore, in the distance distribution  320 , the classes C[ 10 ] to C[ 15 ] and C[ 50 ] to C[ 55 ] are subject presence classes, while other classes are subject absence classes. 
     In addition, as illustrated in  FIG. 7 , a set of distances belonging to the subject presence class is referred to as a subject presence distance range, while a set of distances belonging to the subject absence class is referred to as a subject absence distance range. Therefore, in the distance distribution  320 , a set of distances belonging to the classes C[ 10 ] to C[ 15 ] forms a subject presence distance range  341  (hereinafter may be briefly referred to as a presence range  341 ), while a set of distances belonging to the classes C[ 50 ] to C[ 55 ] forms a subject presence distance range  343  (hereinafter may be briefly referred to as a presence range  343 ). A set of distances disposed between the presence ranges  341  and  343  belonging to classes C[ 16 ] to C[ 49 ] forms a subject absence distance range  342  (hereinafter may be briefly referred to as an absence range  342 ). The subject presence distance range can be said to be a subject distance range in which a subject presence degree of the target input image is relatively large, while the subject absence distance range can be said to be a subject distance range in which a subject presence degree of the target input image is relatively small. 
     In addition, a minimum distance and a maximum distance among subject distances of the target input image  300  are denoted by d MIN  and d MAX , respectively. 
     The subject distance information of the target input image  300  is given to the adjustment map generating portion  52  of  FIG. 3 . The adjustment map generating portion  52  extracts the minimum and the maximum subject distances from the subject distance information of the target input image, and generates the distance distribution based on the subject distance information of the target input image, and detects the above-mentioned subject presence distance range and the subject absence distance range from the distance distribution. When the target input image is the image  300 , the minimum distance d MIN  and the maximum distance d MAX  are extracted from the subject distance information of the target input image  300 , and the distance distribution  320  is generated based on the subject distance information of the target input image  300 , and then the presence ranges  341  and  343  and the absence range  342  are detected from the distance distribution  320 . 
     Based on the distance distribution, the adjustment map generating portion  52  sets the unit adjustment amount and generates an adjustment map on which content of the setting is reflected. The setting of the unit adjustment amount can be performed by the unit adjustment amount generating portion  53  that is a part of the adjustment map generating portion  52 . 
     The setting method of the unit adjustment amount and the generating method of the adjustment map based on the distance distribution will be described. Meanings of the unit adjustment amount and the adjustment map will be apparent from the following description. 
     The adjustment map generating portion  52  splits the distance range from the minimum distance d MIN  to the maximum distance d MAX  into a plurality of unit distance ranges. In this case, by the adjustment map generating portion  52 , a width of the unit distance range for the subject presence distance range is set to be smaller than a width of the unit distance range for the subject absence distance range. For instance, in the example of the distance distribution  320 , step positions d[ 1 ] to d[ 14 ] as illustrated in  FIG. 8  are set. 
     The subject distance at a step position d[i+1] for an arbitrary integer i is larger than the subject distance at a step position d[i], and subject distances at step positions d[ 1 ] and d[ 14 ] are equal to the minimum distance d MIN  and the maximum distance d MAX , respectively. The subject distance at the step position d[i] means a subject distance of a subject that is supposed to be positioned at the step position d[i]. In addition, step positions d[ 1 ] to d[ 6 ] belong to the presence range  341 , step positions d[ 7 ] and d[ 8 ] belong to the absence range  342 , and step positions d[ 9 ] to d[ 14 ] belong to the presence range  343 . A range from the step position d[i] to the step position d[i+1] for an arbitrary integer i is the unit distance range. Therefore, in the example of  FIG. 8 , the distance range from the minimum distance d MIN  to the maximum distance d MAX  is split into thirteen unit distance ranges. A unit distance range from the step position d[i] to the step position d[i+1] is expressed as a unit distance range (d[i], d[i+1]). Of course, the number of the unit distance ranges is not limited to 13. 
     The adjustment map generating portion  52  sets a width of each unit distance range belonging to the presence range  341  and a width of each unit distance range belonging to the presence range  343  to be smaller than a width of each unit distance range belonging to the absence range  342 . As for a given unit distance range, if at least a part of the unit distance range belongs to the absence range  342 , the unit distance range is considered to belong to the absence range  342 . Therefore, the unit distance range (d[ 6 ], d[ 7 ]) can be said to belong to both the presence range  341  and the absence range  342 , but the unit distance range (d[ 6 ], d[ 7 ]) is regarded to belong to the absence range  342 . Similarly, the unit distance range (d[ 8 ], d[ 9 ]) is also regarded to belong to the absence range  342 . 
     Then, the unit distance ranges belonging to the presence range  341  are unit distance ranges (d[ 1 ], d[ 2 ]), (d[ 2 ], d[ 3 ]), (d[ 3 ], d[ 4 ]), (d[ 4 ], d[ 5 ]) and (d[ 5 ], d[ 6 ]). The unit distance ranges belonging to the absence range  342  are unit distance ranges (d[ 6 ], d[ 7 ]), (d[ 7 ], d[ 8 ]) and (d[ 8 ], d[ 9 ]). The unit distance ranges belonging to the presence range  343  are unit distance ranges (d[ 9 ], d[ 10 ]), (d[ 10 ], d[ 11 ]), (d[ 11 ], d[ 12 ]), (d[ 12 ], d[ 13 ]) and (d[ 13 ], d[ 14 ]). 
     As illustrated in  FIG. 9 , the width of each unit distance range belonging to the presence range  341  can be set to a constant width W 341 , the width of each unit distance range belonging to the absence range  342  can be set to a constant width W 342 , and the width of each unit distance range belonging to the presence range  343  can be set to a constant width W 343 . Here, “0&lt;W 341 &lt;W 342 ” and “0&lt;W 343 &lt;W 342 ” are satisfied. The width W 341  and the width W 343  may be the same or may be different from each other. Note that the width of the unit distance range may be different among a plurality of unit distance ranges belonging to the presence range  341 , the width of the unit distance range may be different among a plurality of unit distance ranges belonging to the absence range  342 , and the width of the unit distance range may be different among a plurality of unit distance ranges belonging to the presence range  343 . However, in this case too, as described above, a width of each unit distance range belonging to the presence ranges  341  and  343  is set to be smaller than a width of each unit distance range belonging to the absence range  342 . 
     The width of each unit distance range can work as the unit adjustment amount. Then, a process of setting the step positions d[ 1 ] to d[ 14 ] satisfying the above-mentioned relationship corresponds to the setting process of the unit adjustment amount, and a map of the step positions d[ 1 ] to d[ 14 ] arranged in a predetermined space corresponds to the adjustment map. In other words, for example, when a user performs once the unit operation of instructing to increase the in-focus distance of the target input image  300 , the in-focus distance of the target input image  300  is changed by the digital focus from the subject distance at the step position d[i] to the subject distance at the step position d[i+1]. When the user performs twice the unit operation of instructing to increase the in-focus distance of the target input image  300 , the in-focus distance of the target input image  300  is changed by the digital focus from the subject distance at the step position d[i] to the subject distance at the step position d[i+2]. In this way, the unit adjustment amount of the in-focus state is set finely in the distance ranges ( 341  and  343 ) in which the subject presence degree is high, while the unit adjustment amount of the in-focus state is set roughly in the distance range ( 342 ) in which the subject presence degree is low (see  FIG. 10 ). 
     The in-focus distance and depth of field designation portion  54  sets a designated in-focus distance and a designated depth of field using the adjustment map in accordance with an adjustment instruction operation issued by a user. The adjustment instruction operation is an operation to instruct adjustment (i.e., change) of the in-focus state of the target input image, and is a predetermined operation to the operating portion  18  or a touch panel operation to the display portion  16 , for example. 
     The designated in-focus distance is an in-focus distance after the in-focus state adjustment by the digital focus. In other words, the designated in-focus distance is a target value of the in-focus distance of the target output image obtained by the digital focus. The designated depth of field is a depth of field after the in-focus state adjustment by the digital focus. In other words, the designated depth of field is a target value of the depth of field of the target output image obtained by the digital focus. 
     The designated depth of field is information designating the maximum distance and the minimum distance in the depth of field. The maximum distance and the minimum distance in the designated depth of field correspond to the maximum distance and the minimum distance in the depth of field of the target output image, respectively. Because a difference between the maximum distance and the minimum distance in the depth of field is a depth value of the depth of field, the designated depth of field specifies the depth value of the depth of field of the target output image. Note that the designated depth of field may be information specifying only a depth value of the depth of field. In this case, the depth of field having a depth value specified by the designated depth of field with the center at the designated in-focus distance is the depth of field after the in-focus state adjustment. 
     The designated in-focus distance and the designated depth of field at time point when the adjustment instruction operation is never performed are respectively referred to as an initial value of the designated in-focus distance and an initial value of the designated depth of field. It is preferable that the initial value of the designated in-focus distance and the initial value of the designated depth of field are respectively the same as the in-focus distance and the depth of field before the in-focus state adjustment, namely the in-focus distance and the depth of field of the target input image  300 . The in-focus distance of the target input image  300  can be determined from a state of each lens of the optical system  35  when the target input image  300  is taken (in particular, a position of the focus lens  31 ). The depth value of the depth of field of the target input image  300  can be obtained from an aperture stop value and a focal length when the target input image  300  is taken. When the in-focus distance and the depth value of the depth of field are known, the maximum distance and the minimum distance in the depth of field can be determined. 
     In addition, although not considered particularly in the above description, it is preferable to dispose an in-focus state detection portion  56  for detecting the in-focus distance and the depth of field of the target input image  300  in the imaging apparatus  1  as illustrated in  FIG. 11 , and to generate the adjustment map so that a subject distance of any one of step positions in the adjustment map agrees with the in-focus distance of the target input image  300  (i.e., the initial value of the designated in-focus distance). Thus, the initial value of the designated in-focus distance can agree with a subject distance of any one of step positions (e.g., d[ 4 ]) in the adjustment map. Further, it is possible to generate the adjustment map so that subject distances of any two step positions in the adjustment map agree with the maximum distance and the minimum distance of the depth of field in the target input image  300 . Thus, the maximum distance and the minimum distance of the depth of field determined by the initial value of the designated depth of field can agree with subject distances of any two step positions (e.g., d[ 5 ] and d[ 3 ]) in the adjustment map. 
     Note that it is possible that the in-focus state detection portion  56  also detects an in-focus position of the target input image  300 . The in-focus position of the target input image  300  means a position, on the target input image  300 , in an in-focus area included in the whole image area of the target input image  300 . The in-focus area means an image area in which image data of a focused subject exists. The in-focus area and the in-focus position of the target input image  300  can be detected by using the spatial frequency components or the like of the target input image  300 . 
     The digital focus portion  55  performs the digital focus on the target input image so that the in-focus distance of the target output image agrees with the designated in-focus distance and that the depth of field of the target output image agrees with the designated depth of field. The obtained target output image is displayed on the display portion  16 . 
     With reference to  FIG. 12 , a flow of operation for generating the target output image from the target input image  300  is described.  FIG. 12  is a flowchart illustrating the flow of the operation. First, the subject distance information is generated in Step S 11 . In the next Step S 12 , the adjustment map is generated based on the subject distance information. In other words, the step positions d[ 1 ] to d[ 14 ] including information of the unit adjustment amount is generated. After that, in Step S 13 , the adjustment instruction operation by a user is accepted. If there is the adjustment instruction operation, in Step S 14 , the designated in-focus distance and the designated depth of field are set based on the adjustment map and content of the adjustment instruction operation. The adjustment instruction operation consists of one or more unit operations. 
     If the designated in-focus distance at the present time point is the subject distance at the step position d[i], and if the unit operation to instruct an increase of the in-focus distance is performed j times by a user, the designated in-focus distance is changed to the subject distance at the step position d[i+j]. If the designated in-focus distance at the present time point is the subject distance at the step position d[i], and if the unit operation to instruct a decrease of the in-focus distance is performed j times by a user, the designated in-focus distance is changed to the subject distance at the step position d[i−j](j denotes an integer). However, an upper limit of the designated in-focus distance is a subject distance at the step position d[ 14 ] that agrees with the distance d MAX , and a lower limit of the designated in-focus distance is a subject distance at the step position d[ 1 ] that agrees with the distance d MIN . Therefore, the adjustment instruction operation to instruct an increase of the designated in-focus distance to be larger than the subject distance at the step position d[ 14 ] and the adjustment instruction operation to instruct a decrease of the designated in-focus distance to be smaller than the subject distance at the step position d[ 1 ] are neglected. When the adjustment instruction operation is neglected, a warning display indicating the neglect may be performed. 
     If the maximum distance and the minimum distance in the designated depth of field are the subject distances of step positions d[i A ] and d[i B ], respectively, and if the unit operation to instruct an increase of the depth of field is performed j times by a user, the maximum distance and the minimum distance in the designated depth of field are changed to the subject distances of step positions d[i A +j]  and  d[i B −j], respectively. If the maximum distance and the minimum distance in the designated depth of field are the subject distances of step positions d[i A ] and d[i B ], respectively, and if the unit operation to instruct a decrease of the depth of field is performed j times by a user, the maximum distance and the minimum distance in the designated depth of field are changed to the subject distances of step positions d[i A −j] and d[i B +j]. Symbols i A  and i B  denote integers that satisfy “i A &gt;i B &gt;0”. 
     Alternatively, if the maximum distance and the minimum distance in the designated depth of field are subject distances at the step positions d[i A ] and d[i B ], respectively, and if the unit operation to instruct an increase of the depth of field is performed j times, the minimum distance in the designated depth of field may be maintained to be the subject distance at the step position d[i B ] while the maximum distance in the designated depth of field may be changed to the subject distance at the step position d[i A +j] or, alternatively, the maximum distance in the designated depth of field may be maintained to be the subject distance at the step position d[i A ] while the minimum distance in the designated depth of field may be changed to the subject distance in the step position d[i B −j]. Similarly, if the maximum distance and the minimum distance in the designated depth of field are the subject distances at the step positions d[i A ] and d[i B ], respectively, and if the unit operation to instruct a decrease of the depth of field j times, the minimum distance in the designated depth of field may be maintained to be the subject distance at the step position d[i B ] while the maximum distance in the designated depth of field may be changed to the subject distance at the step position d[i A −j] or, alternatively, the maximum distance in the designated depth of field may be maintained to be the subject distance at the step position d[i A ] while the minimum distance in the designated depth of field may be changed to the subject distance at the step position d[i B +j]. 
     However, an upper limit of the maximum distance in the designated depth of field is a subject distance at the step position d[ 14 ] that agrees with the distance d MAX , and a lower limit of the minimum distance in the designated depth of field is a subject distance at the step position d[ 1 ] that agrees with the distance d MIN . Therefore, the adjustment instruction operation to instruct an increase of the maximum distance in the designated depth of field to be larger than the subject distance at the step position d[ 14 ] and the adjustment instruction operation to instruct a decrease of the minimum distance in the designated depth of field to be smaller than the subject distance at the step position d[ 1 ] are neglected. Further, the adjustment instruction operation to instruct a decrease of the designated depth value of the depth of field to be zero or smaller is also neglected. For instance, if i A =4 and i B =3 are satisfied, the adjustment instruction operation to instruct a decrease of the depth of field is neglected. When the adjustment instruction operation is neglected, a warning display indicating the neglect may be performed. 
     After Step S 14  illustrated in  FIG. 12 , Step S 15  is performed. In Step S 15 , the target output image having the in-focus distance and the depth of field according to the latest designated in-focus distance and designated depth of field is generated by the digital focus, and the generated target output image is displayed. 
     After that, in Step S 16 , the main control portion  20  illustrated in  FIG. 1  accepts user&#39;s one more adjustment instruction operation or adjustment confirming operation. When the one more adjustment instruction operation is performed, the process flow goes back to Step S 14 , and the process of Step S 14  and thereafter is performed repeatedly. In other words, the designated in-focus distance and the designated depth of field are reset based on the adjustment map and content of the one more adjustment instruction operation, and the target output image in accordance with the reset designated in-focus distance and designated depth of field is regenerated by the digital focus and is displayed. 
     If the adjustment confirming operation is performed in Step S 16 , the image data of the currently displayed target output image is recorded in the recording medium  19  (Step S 17 ). In this case, additional data may be recorded in the recording medium  19  in association with the image data of the target output image. The additional data may contain a latest designated in-focus distance and a latest designated depth of field. 
     As illustrated in  FIG. 13 , it is supposed that the operating portion  18  is equipped with four buttons  61  to  64 , and more specific operational example is described. It is supposed that an operation of pressing the button  61  one time is the one unit operation to instruct an increase of the in-focus distance, and an operation of pressing the button  62  one time is the one unit operation to instruct a decrease of the in-focus distance. Note that if a touch panel is used for the unit operation, the buttons  61  to  64  may be buttons displayed on a display screen. 
     Now, it is supposed that the in-focus distance of the target input image  300  agrees with the subject distance at the step position d[ 4 ]. In this situation, if the button  61  is pressed once, twice, three times, four times, five times, six times or seven times, the designated in-focus distance is changed to the subject distance of the step position d[ 5 ], d[ 6 ], d[ 7 ], d[ 8 ], d[ 9 ], d[ 10 ] or d[ 11 ], respectively. In addition, although different from the situation illustrated in  FIG. 5A , in the situation where the in-focus distance of the target input image  300  is agreed with the subject distance at the step position d[ 11 ], if the button  62  is pressed once, twice, three times, four times, five times, six times or seven times, the designated in-focus distance is changed to the subject distance at the step positions d[ 10 ], d[ 9 ], d[ 8 ], d[ 7 ], d[ 6 ], d[ 5 ] or d[ 4 ], respectively. In this way, when the designated in-focus distance is changed in presence ranges  341  and  343 , the designated in-focus distance is changed in detail by the unit operation. On the other hand, when the designated in-focus distance is changed in the absence range  342 , the designated in-focus distance is changed roughly by the unit operation. 
     In addition, it is supposed that an operation of pressing the button  63  one time is the one unit operation to instruct an increase of the depth of field, and that an operation of pressing the button  64  one time is the one unit operation to instruct a decrease of the depth of field. The user can designate by another operation whether only the maximum distance in the depth of field should be changed, or only the minimum distance in the depth of field should be changed, or both of them should be changed by an operation of the button  63 . Similarly, the user can designate by another operation whether only the maximum distance in the depth of field should be changed, or only the minimum distance in the depth of field should be changed, or both of them should be changed by an operation of the button  64 . Here, for convenience sake of description, an operational example is described, in which only the maximum distance in the depth of field is changed by the operation of the button  63 , and only the minimum distance in the depth of field is changed by the operation of the button  64 . 
     It is supposed that the maximum distance in the depth of field of the target input image  300  agrees with the subject distance at the step position d[ 5 ]. In this situation, when the button  63  is pressed once, twice, three times, four times, five times or six times, the maximum distance in the designated depth of field is changed to the subject distance of the step position d[ 6 ], d[ 7 ], d[ 8 ], d[ 9 ], d[ 10 ] or d[ 11 ], respectively. In addition, although different from the situation illustrated in  FIG. 5A , in the situation where the maximum distance and the minimum distance in the depth of field of the target input image  300  agree with the subject distances at the step positions d[ 12 ] and d[ 5 ], if the button  64  is pressed once, twice, three times, four times, five times or six times, the minimum distance in the designated depth of field is changed to the subject distance at the step position d[ 6 ], d[ 7 ], d[ 8 ], d[ 9 ], d[ 10 ] or d[ 11 ], respectively. In this way, when the maximum distance or the minimum distance in the designated depth of field is changed in the presence ranges  341  and  343 , the maximum distance or the minimum distance is changed in detail by the unit operation. On the other hand, when the maximum distance or the minimum distance in the designated depth of field is changed in the absence range  342 , the maximum distance or the minimum distance is changed roughly by the unit operation. 
     Note that an operation of pressing the button  61  continuously (a so-called long press operation) may be regarded as a plurality of times of the unit operation. The same is true for the buttons  62  to  64 . 
     When trying to adjust the in-focus state by the digital focus, the user usually pays attention to any one subject for adjusting the in-focus state. For instance, the in-focus distance is adjusted in detail so that a specific person in the subject  301  is best focused, or the in-focus distance is adjusted in detail so that a specific tree in the subject  302  is best focused (see  FIG. 4 ). In addition, for example, the depth of field is decreased slightly so that only the specific person in the subject  301  is focused, or the depth of field is increased slightly so that a person positioned close to the specific person is also focused. Therefore, in distance ranges ( 341  and  343 ) having a high subject presence degree, it is necessary to set the unit adjustment amount of the in-focus state in detail. On the other hand, even if the unit adjustment amount of the in-focus state is set in detail in the distance range ( 342 ) having a low subject presence degree, it is less use. It is rather preferable to set the same roughly so that the designated in-focus distance can be quickly changed from a vicinity of the subject distance d 301  to the vicinity of the subject distance d 302  or from a vicinity of the subject distance d 302  to the vicinity of the subject distance d 301 . Similarly, it is possible to change the maximum distance or the minimum distance in the designated depth of field quickly from the vicinity of the subject distance d 301  to the vicinity of the subject distance d 302  or from the vicinity of the subject distance d 302  to the vicinity of the subject distance d 301 . 
     Based on this consideration, in this embodiment, the unit adjustment amount is set in detail in the distance ranges ( 341  and  343 ) having a high subject (i.e., object) presence degree so that fine adjustment of the in-focus state can be performed. In the distance range ( 342 ) having a low subject presence degree, the unit adjustment amount is set roughly so that rough adjustment of the in-focus state can be performed. Thus, adjustment in accordance with user&#39;s intention is realized so that user&#39;s operation for the in-focus state adjustment can be simplified. 
     During execution of the process of Steps S 11  to S 17  illustrated in  FIG. 12 , as illustrated in  FIG. 14 , it is possible to display the adjustment map together with the target output image. In the situation where the adjustment instruction operation is not performed yet, the target output image is the same as the target input image.  FIG. 14  illustrates a display screen  16   A  of the display portion  16  on which the target output image is displayed. In  FIG. 14 , the dot-filled area indicates a casing of the display portion  16  (the same is true in  FIG. 15  that will be referred to later). In the example illustrated in  FIG. 14 , the adjustment map is displayed as a bar icon  360  on the display screen  16   A . The bar icon  360  is provided with lines corresponding to the step positions, and an icon  361  indicating the designated in-focus distance and the designated depth of field at the present time point is displayed on the bar icon  360 . By viewing the bar icon  360  and the icon  361 , the user can directly recognize the designated in-focus distance and the designated depth of field at the present time point and can recognize whether an adjustment mode at the present time point is a fine adjustment mode or a rough adjustment mode. 
     The fine adjustment mode means an adjustment mode in the state where the designated in-focus distance belongs to the subject presence distance range, and the rough adjustment mode means an adjustment mode in the state where the designated in-focus distance belongs to the subject absence distance range (see  FIG. 7 ). Alternatively, the fine adjustment mode means an adjustment mode in the state where the maximum distance and the minimum distance in the designated depth of field belong to the subject presence distance range, and the rough adjustment mode means an adjustment mode in the state where at least one of the maximum distance and the minimum distance in the designated depth of field belongs to the subject absence distance range. 
     During execution of the process of Steps S 11  to S 17  illustrated in  FIG. 12 , an index  370  indicating which one of the fine adjustment mode and the rough adjustment mode is the adjustment mode at the present time point may be displayed together with the target output image as illustrated in  FIG. 15 . By this too, as a matter of course, the user can recognize whether the adjustment mode at the present time point is the fine adjustment mode or the rough adjustment mode. It is preferable to display the index  370  illustrated in  FIG. 15  and the bar icon  360  and the icon  361  illustrated in  FIG. 14  at the same time. 
     Second Embodiment 
     A second embodiment of the present invention is described. The second embodiment is an embodiment based on the first embodiment, and the description in the first embodiment is applied also to second embodiment unless otherwise noted, as long as no contradiction arises. 
     In the second embodiment, the structure illustrated in  FIG. 11  is used, setting of the unit adjustment amount and generation of the adjustment map are performed based on the in-focus distance of the target input image  300  detected by the in-focus state detection portion  56  and the subject distance information from the subject distance information generating portion  51 . 
     Similarly to the first embodiment, it is supposed that the target input image is the image  300  illustrated in  FIG. 5A . In this case, the adjustment map generating portion  52  generates the adjustment map for the depth of field based on the minimum distance d MIN  and the maximum distance d MAX  extracted from the subject distance information and the in-focus distance d O  of the target input image  300 . Here, it is supposed that the minimum distance d MIN  and the maximum distance d MAX  are the same as the subject distances at the step positions d[ 1 ] and d[ 14 ], respectively, similarly to the first embodiment, and that the adjustment map generating portion  52  generates the adjustment map consisting of the step positions d[ 1 ] to d[ 14 ]. 
     As illustrated in  FIG. 16 , the adjustment map generating portion  52  sets a distance range having the center at the in-focus distance d O  and having a predetermined distance width dW as the fine adjustment range, and sets a distance range that does not belong to the fine adjustment range as the rough adjustment range (dW&gt;0). Then, the fine adjustment range is split into a plurality of unit distance ranges. The unit distance range means a range from the step position d[i] to the step position d[i+1] as described above in the first embodiment.  FIG. 16  illustrates an example of the fine adjustment range and the rough adjustment range to be set. In this example, the in-focus distance d O  is the same as the subject distance at the step position d[ 7 ], a distance range from the step position d[ 4 ] to the step position d[ 10 ] is set as a fine adjustment range  402 , a distance range from the step position d[ 1 ] to the step position d[ 4 ] is set as a rough adjustment range  401 , and a distance range from the step position d[ 10 ] to the step position d[ 14 ] is set as a rough adjustment range  403 . Note that the step positions d[ 4 ] and d[ 10 ] are supposed to belong not to the rough adjustment ranges  401  and  403  but to the fine adjustment range  402 . In addition, it is supposed that the step position d[ 1 ] also belongs to the rough adjustment range  401 , and that the step position d[ 14 ] also belongs to the rough adjustment range  403 . 
     Note that if an inequality “d O −d MIN &lt;dW/2” is satisfied because of any reason such as the reason that the in-focus distance d O  is close to the minimum distance d MIN , the fine adjustment range that is once set as the distance range having the center at the in-focus distance d O  and having the distance width dW is reduced and corrected so as not to include distances smaller than the minimum distance d MIN . Similarly, if an inequality “d MAX −d O &lt;dW/2” is satisfied because of any reason such as the reason that the in-focus distance d O  is close to the maximum distance d MAX , the fine adjustment range that is once set as the distance range having the center at the in-focus distance d O  and having the distance width dW is reduced and corrected so as not to include distances larger than the maximum distance d MAX . In the example illustrated in  FIG. 16 , the reduction and correction is not performed. 
     The adjustment map generating portion  52  sets the width of each unit distance range belonging to the fine adjustment range  402  smaller than the width of each unit distance range belonging to the rough adjustment ranges  401  and  403 . 
     The unit distance ranges belonging to the rough adjustment range  401  are unit distance ranges (d[ 1 ], d[ 2 ]), (d[ 2 ], d[ 3 ]) and (d[ 3 ], d[ 4 ]), the unit distance ranges belonging to the fine adjustment range  402  are unit distance ranges (d[ 4 ], d[ 5 ]), (d[ 5 ], d[ 6 ]), (d[ 6 ], d[ 7 ]), (d[ 7 ], d[ 8 ]), (d[ 8 ], d[ 9 ]) and (d[ 9 ], d[ 10 ]), and the unit distance range belonging to the rough adjustment range  403  are unit distance ranges (d[ 10 ], d[ 11 ]), (d[ 11 ], d[ 12 ]), (d[ 12 ], d[ 13 ]) and (d[ 13 ], d[ 14 ]). 
     As illustrated in  FIG. 17 , the width of each unit distance range belonging to the rough adjustment range  401  can be a constant width W 401 , the width of each unit distance range belonging to the fine adjustment range  402  can be a constant width W 402 , and the width of each unit distance range belonging to the rough adjustment range  403  can be a constant width W 403 . Here, “0&lt;W 402 &lt;W 401 ” and “0&lt;W 402 &lt;W 403 ” are satisfied. The width W 401  and the width W 403  may be the same or different from each other. Note that the width of the unit distance range may be different among a plurality of unit distance ranges belonging to the rough adjustment range  401 , the width of the unit distance range may be different among a plurality of unit distance ranges belonging to the fine adjustment range  402 , and the width of the unit distance range may be different among a plurality of unit distance ranges belonging to the rough adjustment range  403 . However, in this case too, as described above, the width of each unit distance range belonging to the fine adjustment range  402  is set to be smaller than the width of each unit distance range belonging to the rough adjustment ranges  401  and  403 . 
     The width of each unit distance range can work as the unit adjustment amount. Then, the process of setting the step positions d[ 1 ] to d[ 14 ] satisfying the above-mentioned relationship corresponds to the setting process of the unit adjustment amount, and a map in which the step positions d[ 1 ] to d[ 14 ] are arranged in a predetermined space corresponds to the adjustment map. However, the step positions d[ 1 ] to d[ 14 ] described in this embodiment is used only for adjustment of the depth of field. In other words, the map in which the step positions d[ 1 ] to d[ 14 ] are arranged as described in this embodiment is the adjustment map for the depth of field. The adjustment map for the in-focus distance is set based on the distance distribution  320  as described above in the first embodiment (see  FIGS. 8 ,  9  and the like). 
     An operation after generating the adjustment map is the same as that described above in the first embodiment, and the operation flow of generating the target output image from the target input image  300  is the same as that in the first embodiment (see  FIG. 12 ). 
     In other words, in Step S 12  of  FIG. 12 , the adjustment map for the in-focus distance is generated based on the distance distribution  320  and the adjustment map for the depth of field is generated based on the minimum distance d MIN , the maximum distance d MAX  and the in-focus distance d O . After that, the adjustment instruction operation by the user is accepted in Step S 13 . If the adjustment instruction operation for the in-focus distance is accepted, the designated in-focus distance is set based on the adjustment map for the in-focus distance and content of the adjustment instruction operation in Step S 14 . If the adjustment instruction operation for the depth of field is accepted, the designated depth of field is set based on the adjustment map for the depth of field and content of the adjustment instruction operation in Step S 14 . The setting method of the designated in-focus distance is the same as that in the first embodiment. 
     The setting method of the designated depth of field is also the same as that in the first embodiment, but the step positions illustrated in  FIGS. 16 and 17  are used as step positions of the subject distances to be the maximum distance and the minimum distance of the designated depth of field. Therefore, in the fine adjustment range  402  that is a distance range near the in-focus distance d O , the depth of field can be adjusted in detail because the unit adjustment amount is set in detail. On the other hand, in the rough adjustment ranges  401  and  403  that are distance ranges apart from the in-focus distance d O , the depth of field is changed roughly because the unit adjustment amount is set roughly. 
     When trying to adjust the in-focus state by the digital focus, the user usually pays attention to any one of subjects for adjusting the in-focus state. For instance, the depth of field is decreased by a slight amount so that only the specific person in the subject  301  is focused, or the depth of field is increased by a slight amount so that a person positioned close to the specific person is also focused. On the other hand, such a specific person is usually positioned in the vicinity of the in-focus distance d O  when the target input image  300  is taken. Therefore, in the distance range ( 402 ) near the in-focus distance d O , it is preferable to set the unit adjustment amount of the depth of field in detail so as to satisfy the user&#39;s intention. On the other hand, even if the unit adjustment amount of the depth of field is set in detail in the distance ranges ( 401  and  403 ) that are far from the in-focus distance d O , it is less use. It is rather preferable to set the same roughly so that the adjustment operation for setting a subject in a long distant to be in the depth of field can be performed quickly. 
     Based on this consideration, in this embodiment, the unit adjustment amount for the depth of field is set in detail, in the distance range ( 402 ) close to the in-focus distance d O , so that fine adjustment of the depth of field can be performed. In the distance ranges ( 401  and  403 ) that are far from the in-focus distance d O , the unit adjustment amount for the depth of field is set roughly so that the depth of field is roughly adjusted. Thus, adjustment in accordance with user&#39;s intention is realized, and user&#39;s operation for the in-focus state adjustment can be simplified. 
     Note that the display illustrated in  FIG. 14  or  15  can be performed in the second embodiment, too. In other words, during execution of the process of Steps S 11  to S 17  of  FIG. 12 , the adjustment map for the depth of field may be displayed together with the target output image. The display method of the adjustment map is the same as that described above in the first embodiment. Similarly, during execution of the process of Steps S 11  to S 17  of  FIG. 12 , an index indicating which one of the fine adjustment mode and the rough adjustment mode is the current adjustment mode for the depth of field may be displayed together with the target output image. The fine adjustment mode for the depth of field means an adjustment mode in the state where the maximum distance and the minimum distance in the designated depth of field belong to the fine adjustment range  402 , and the rough adjustment mode for the depth of field means an adjustment mode in the state where at least one of the maximum distance and the minimum distance in the designated depth of field belongs to the rough adjustment range  401  or  403 . 
     In addition, the in-focus distance d O  and the subject distance information are used for generating the adjustment map for the depth of field in this embodiment, but the fine adjustment range and the rough adjustment range are determined depending mainly on the in-focus distance d O , and the subject distance information is merely used for setting the upper and lower limits of the fine adjustment range or the upper and lower limits of the rough adjustment range. Therefore, if the step positions d[ 1 ] and d[ 14 ] are determined in advance, it is possible to generate the adjustment map for the depth of field based on only the in-focus distance d O . 
     Third Embodiment 
     A third embodiment of the present invention is described. In the third embodiment, an example of a method of the digital focus performed by the digital focus portion  55  is described. 
     As a method of changing the in-focus distance and the depth of field of the target input image, the digital focus portion  55  can use any method such as a known method. For instance, the above-mentioned light field method can be used. Using the light field method, a target output image having any in-focus distance and depth of field can be generated from the target input image based on the output signal of the image sensor  33 . In this case, a known method based on the light field method (e.g., the method described in WO/06/039486 Pamphlet or JP-A-2009-224982) can be used. As described above, in the light field method, by using an imaging lens having an aperture stop and a micro lens array, the image signal (image data) obtained from the image sensor contains information of the light propagation direction in addition to light intensity distribution on the light receiving surface of the image sensor. The imaging apparatus adopting the light field method performs image processing based on the image signal from the image sensor and can reconstruct an image having any in-focus distance and depth of field. In other words, if the light field method is used, a target output image in which any subject is focused can be constructed freely after taking the target input image. 
     Therefore, although not illustrated in  FIG. 2 , an optical member necessary for realizing the light field method is disposed in the imaging portion  11  when the light field method is used. This optical member includes a micro lens array and the like as described above in the first embodiment, and the incident light from the subject enters the light receiving surface (i.e., the imaging surface) of the image sensor  33  via the micro lens array and the like. The micro lens array consists of a plurality of micro lenses, and one micro lens is assigned to the one or more light receiving pixels on the image sensor  33 . Thus, the output signal of the image sensor  33  contains information of the incident light propagation direction to the image sensor  33  in addition to the light intensity distribution on the light receiving surface of the image sensor  33 . By using the image data of the target input image containing this information, the digital focus portion  55  can freely change the in-focus distance and the depth of field of the target input image. 
     The digital focus portion  55  can also perform the digital focus by a method that is not based on the light field method. For instance, the digital focus may include an image restoring process to eliminate deterioration due to a blur in the target input image. As a method of the image restoring process, a known method can be used. When the image restoring process is performed, it is possible to use not only the target input image but also image data of one or more frame images taken at timing close to the target input image. The target input image after the image restoring process is referred to as a whole in-focus image. In the whole in-focus image, the whole image area is the in-focus area. 
     After the whole in-focus image is generated, the digital focus portion  55  can generate the target output image by performing a filtering process on the whole in-focus image using the designated in-focus distance, the designated depth of field and the subject distance information. In other words, any one pixel in the whole in-focus image is set as a noted pixel so that the subject distance of the noted pixel is extracted from the subject distance information, and a distance difference between the subject distance of the noted pixel and the designated in-focus distance is determined. Then, the filtering process is performed on a micro image area having the center at the noted pixel so that the image in the micro image area is blurred more largely as the distance difference determined for the noted pixel is larger. However, if the distance difference is smaller than or equal to a half of the designated depth value of the depth of field, execution of the filtering process can be stopped. The above-mentioned process is performed on pixels in the whole in-focus image sequentially as the noted pixel, and a result image obtained after the whole filtering process is finished can be used as the target output image. 
     &lt;&lt;Variations&gt;&gt; 
     The embodiments of the present invention can be modified variously as necessary within the scope of the technical concept described the claims. The embodiments are merely examples of embodying the present invention, and meanings of terms in the present invention and elements thereof should not be limited to those described in the embodiments. The specific values shown in the above-mentioned description are merely examples and can be changed variously as a matter of course. As annotations that can be applied to the above-mentioned embodiments, Note 1 to Note 3 are described below. The contents of the notes can be combined freely as long as no contradiction arises. 
     [Note 1] 
     The setting method of the unit adjustment amount according to the present invention is used for both the in-focus distance and the depth of field in the above-mentioned embodiments, but the setting method of the unit adjustment amount according to the present invention may be used for only one of the in-focus distance and the depth of field. 
     [Note 2] 
     The imaging apparatus  1  accepts the adjustment instruction operation and performs the digital focus in the above-mentioned embodiments, but it is possible that electronic equipment (not shown) other than the imaging apparatus  1  accepts the adjustment instruction operation and performs the digital focus. Here, the electronic equipment is, for example, a personal computer or an information terminal such as a personal digital assistant (PDA). Note that the imaging apparatus  1  is a type of the electronic equipment. The electronic equipment is equipped with the portions illustrated in  FIG. 3  or the portions illustrated in  FIG. 11 , for example. The image data of the target input image and information necessary for generating the adjustment map are supplied to the electronic equipment. The adjustment instruction operation is given to the electronic equipment. Thus, the target output image can be generated, displayed and recorded on the electronic equipment. 
     [Note 3] 
     The imaging apparatus  1  illustrated in  FIG. 1  or the above-mentioned electronic equipment can be constituted of hardware, or a combination of hardware and software. When the imaging apparatus  1  or the above-mentioned electronic equipment is constituted using software, the block diagram of each portion realized by the software expresses a functional block diagram of the portion. The function realized using the software may be described as a program, and the program may be executed by a program executing device (e.g., a computer) so that the function is realized.