Patent Publication Number: US-9894270-B2

Title: Image processing apparatus and image processing method for handling a raw image, of a moving image or a still image

Description:
TECHNICAL FIELD 
     The present invention relates to an image processing apparatus and an image processing method. In particular, it relates to a technique for handling a RAW image of a moving image or a still image. 
     BACKGROUND ART 
     Conventionally, imaging apparatuses perform de-Bayer processing (de-mosaic processing) on raw image information (RAW image) captured by an image sensor, convert the image into signals including luminance and color difference, and perform so-called development processing including noise removal, optical distortion correction, and image optimization for each signal. Generally, after such development processing, the luminance and color-difference signals are compressed and coded and are finally recorded in a storage medium. 
     Other conventional imaging apparatuses are capable of recording RAW images. When a RAW image is recorded, a large amount of data needs to be recorded. However, since correction of or deterioration of original images can be minimized and RAW images can be edited after being captured, which are advantages in recording RAW images, advanced-level users preferably use this type of imaging apparatuses. 
     Japanese Patent Application Laid-Open No. 2011-244423 discusses an imaging apparatus capable of recording RAW images. According to Japanese Patent Application Laid-Open No. 2011-244423, development parameters are recorded along with a RAW image, and when reproduction is performed, these development parameters are used to develop and reproduce the RAW image. 
     In recent years, imaging apparatuses have been equipped with more advanced image sensors, and the number of pixels per image has been significantly increasing. In addition, a trend is that the number of images that can be continuously captured per second is increasing. Thus, the amount of processing including de-Bayer processing on a RAW image and development processing such as noise removal and optical distortion correction are synergistically increasing. As a result, performing real-time development processing simultaneously with an image capturing operation requires more circuits and power consumption. Development processing requires a larger circuit area or imposes constraints on power consumption. Therefore, in some cases, high image capturing performance cannot be achieved. 
     On the other hand, as discussed in the above Japanese Patent Application Laid-Open No. 2011-244423, if a RAW image is recorded without being developed, the amount of processing required for development during the image capturing operation could be reduced. However, since the RAW image is recorded without being developed, it is difficult to promptly reproduce and display the image. In addition, because of the particularity of data unique to RAW images, the RAW images may not be reproduced (developed) by other devices. Namely, with conventional RAW image recording methods, user-friendliness could be deteriorated. 
     Thus, there are problems to be addressed for enabling conventional apparatuses to achieve high image capturing performance and to promptly display reproduced images. That is, it is necessary to mount high-cost circuits on the apparatuses and to drive the apparatuses with higher power or RAW images need to be recorded and reproduced promptly and simply. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] 
     Japanese Patent Application Laid-Open No. 2011-244423 
     SUMMARY OF INVENTION 
     The present invention is directed to a technique for achieving prompt display of a reproduction image of a RAW image by using a configuration for recording a RAW image. In addition, the present invention is directed to a technique for achieving prompt display and high-quality image display of a necessary portion by using a developed and recorded image and a recorded RAW image. 
     According to one aspect of the present invention, an image processing apparatus includes an imaging unit configured to capture an object image and generate information representing a RAW image, a first development unit configured to acquire the information representing the RAW image and develop the RAW image, a storage unit configured to store an image file of an image developed by the first development unit and a RAW file which stores the information representing the RAW image directly as a RAW image in a memory, a second development unit configured to read the RAW file stored in the memory in a predetermined interval or in an idle state and develop the RAW image to obtain an image having higher image quality than that obtained by the first development unit, and a reproduction unit configured to reproduce, if an instruction for starting reproduction of a certain image is given and the second development unit has not completed developing of the RAW image, the image obtained from the image file and developed by the first development unit and to reproduce, if the second development unit has completed developing of the RAW image, the image developed by the second development unit. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating a configuration of an imaging apparatus according to an exemplary embodiment of the present invention. 
         FIG. 2  is a state transition diagram according to the present exemplary embodiment. 
         FIG. 3  is a flowchart illustrating processing in a still image capturing mode according to the present exemplary embodiment. 
         FIG. 4A  illustrates configurations of a still image file and a RAW file according to the present exemplary embodiment. 
         FIG. 4B  illustrates configurations of a still image file and a RAW file according to the present exemplary embodiment 
         FIG. 5  is a flowchart illustrating processing in an idle state according to the present exemplary embodiment. 
         FIG. 6  is a flowchart illustrating processing in a still image reproduction mode according to the present exemplary embodiment. 
         FIG. 7A  illustrates display processing in the still image reproduction mode according to the present exemplary embodiment. 
         FIG. 7B  illustrates display processing in the still image reproduction mode according to the present exemplary embodiment. 
         FIG. 7C  illustrates display processing in the still image reproduction mode according to the present exemplary embodiment. 
         FIG. 8  is a flowchart illustrating processing in a moving image capturing mode according to the present exemplary embodiment. 
         FIG. 9A  illustrates configurations of a moving image file and a RAW moving image file according to the present exemplary embodiment. 
         FIG. 9B  illustrates configurations of a moving image file and a RAW moving image file according to the present exemplary embodiment. 
         FIG. 10  is a flowchart illustrating processing in a moving image reproduction mode according to the present exemplary embodiment. 
         FIG. 11  illustrates a pixel array. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings. 
       FIG. 1  is a block diagram illustrating a configuration of an imaging apparatus  100  according to an exemplary embodiment of the present invention. The imaging apparatus  100  illustrated in  FIG. 1  can not only record image information obtained by capturing an image of an object in a storage medium but also reproduce image information read from a storage medium. In addition, the imaging apparatus  100  can develop and display such image information and exchange the image information with external devices or servers (cloud), for example. Thus, the imaging apparatus  100  according to an exemplary embodiment of the present invention can be expressed as an image processing apparatus, a recording apparatus, a reproduction apparatus, a recording and reproduction apparatus, or a communication apparatus. 
     In  FIG. 1 , a control unit  161  includes a central processing unit (CPU) and a memory storing a control program to be executed by the CPU. The control unit  161  controls overall processing of the imaging apparatus  100 . An operation unit  162  includes an input device including keys, buttons, and a touch panel for a user to give instructions to the imaging apparatus  100 . The control unit  161  detects an operation signal from the operation unit  162  and controls the imaging apparatus  100  so that the imaging apparatus  100  performs an operation suitable for the operation signal. A display unit  123  includes a liquid crystal display (LCD) for displaying an image captured or reproduced by the imaging apparatus  100 , a menu screen, and various types of information. 
     If a user gives an instruction for starting an image capturing operation via the operation unit  162 , an optical image of a target object is input via an imaging optical unit  101  and the optical image is formed on an image sensor unit  102 . When an image is captured, a camera control unit  104  controls operations of the imaging optical unit  101  and the image sensor unit  102 , based on calculation results of evaluation values about the diaphragm, the focus, the camera shake, and the like acquired by an evaluation value calculation unit  105  and based on object information about a face recognition result or the like extracted by a recognition unit  131 . 
     The image sensor unit  102  converts light transmitted through red, green, and blue (RGB) mosaic color filters into electrical signals, one filter being arranged for each pixel.  FIG. 11  illustrates color filters arranged in the image sensor unit  102 .  FIG. 11  illustrates a pixel array of an image handled by the imaging apparatus  100 . As illustrated in  FIG. 11 , the red (R), green (G), and blue (B) filters are arranged in a mosaic pattern, one filter being arranged per pixel. Each set of 4 pixels in 2 rows and 2 columns (one red pixel, one blue pixel, and two green pixels) is regularly arranged side by side. Such pixel arrangement is generally called a Bayer array. 
     A sensor signal processing unit  103  performs pixel restoration processing on the converted electrical signal obtained by the image sensor unit  102 . The sensor signal processing unit  103  performs the restoration processing on values of missing pixels or low-reliability pixels obtained by the image sensor unit  102 , by using values of neighboring pixels. In this way, the sensor signal processing unit  103  interpolates restoration target pixels and subtracts predetermined offset values. In the present exemplary embodiment, the image information output from the sensor signal processing unit  103  is referred to as RAW image information (which will hereinafter be referred to as a RAW image), which signifies an raw (undeveloped) image (control until  104 , imaging optical unit  101 , image sensor unit  102 , and sensor processing unit  103  can also be referred to as a imaging unit). 
     A development unit  110  develops such RAW image. The development unit  110  includes a plurality of different development processing units. The development unit  110  includes a simple development unit  111  as a first development unit and a high-quality image development unit  112  as a second development unit. In addition, the development unit  110  includes a switch unit  121  selecting an output from the unit  111  or  112 . Both the simple development unit  111  and the high-quality image development unit  112  perform de-Bayer processing (de-mosaic processing), namely, color interpolation processing, on a RAW image. These development units  111  and  112  convert the RAW image into luminance and color difference (or primary color) signals, remove noise included in each signal, correct optical distortion, and optimize the image. Namely, these development units  111  and  112  perform so-called development processing. 
     In particular, the high-quality image development unit  112  performs each processing more accurately than the simple development unit  111 . By performing each processing more accurately, the high-quality image development unit  112  produces a developed image with higher image quality than that produced by the simple development unit  111 . However, the processing load of the high-quality image development unit  112  is larger than that of the simple development unit  111 . Thus, the high-quality image development unit  112  in the present exemplary embodiment is not configured such as to perform real-time development simultaneously with an image capturing operation. The high-quality image development unit  112  is configured to be capable of performing distributed processing when there is sufficient time in an idle period after an image capturing operation. By allowing the high-quality image development unit  112  to perform high-quality image development when there is sufficient time after an image capturing operation, instead of performing the high-quality image development during an image capturing operation, the increase (peak) in circuit scale or power consumption can be reduced to a low level. In contrast, the simple development unit  111  is configured to require a lower processing amount for development than that required for the high-quality image development, so that the simple development unit  111  can perform development processing more quickly than the high-quality image development unit  112  during an image capturing operation. However, a developed image produced by the simple development unit  111  has lower quality than that produced by the high-quality image development unit  112 . Since the processing load of the simple development unit  111  is lower, the simple development unit  111  is mainly used when the imaging apparatus  100  performs real-time development simultaneously with an image capturing operation. The switch unit  121  is changed over by the control unit  161  in accordance with an operation input by the user via the operation unit  162 , or a current operation mode. In addition, only one unit to which a signal is output, namely, either the simple development unit  111  or the high-quality image development unit  112 , may perform a development operation, in conjunction with change-over of the switch unit  121 . 
     In the present exemplary embodiment, the development unit  110  separately includes the simple development unit  111  and the high-quality image development unit  112 . However, alternatively, a single development unit may be arranged to selectively perform simple development processing and high-quality image development processing by switching an operation mode. 
     A display processing unit  122  performs predetermined display processing on the image information developed by the development unit  110 . Next, the display unit  123  displays the image. In addition, the developed image information can be output to an external display device via a video output terminal  124 . Examples of the video output terminal  124  include a general-purpose interface such as a high-definition multimedia interface (HDMI) or a serial digital interface (SDI). 
     The image information developed by the development unit  110  is also supplied to the evaluation value calculation unit  105 . The evaluation value calculation unit  105  calculates evaluation values such as those indicating the focus state and the exposure state from the image information. 
     The image information developed by the development unit  110  is also supplied to the recognition unit  131 . The recognition unit  131  has a function of detecting and recognizing object information such as a face or a person in the image information. For example, if the recognition unit  131  detects a face on a screen represented by the image information, the recognition unit  131  outputs information representing the position of the face. In addition, for example, the recognition unit  131  performs authentication of a certain person, based on information about a feature such as a face. 
     The image information developed by the development unit  110  is supplied to a still image compression unit  141  or a moving image compression unit  142 . The still image compression unit  141  and the moving image compression unit  142  are used for compressing the image information as a still image and as a moving image, respectively. The still image compression unit  141  and the moving image compression unit  142  perform high-efficiency coding (compression coding) on the target image information, generate image information having a compressed information amount, and convert the image information into an image file (a still image file or a moving image file). JPEG or the like can be used for compression of a still image while MPEG-2, H.264, H.265, or the like can be used for compression of a moving image. 
     A RAW compression unit  113  performs high-efficiency coding on data of the RAW image output from the sensor signal processing unit  103 , by using a technique such as wavelet transform or differential coding, converts the data into a compressed RAW file, and stores the RAW file in a buffer unit (storage medium)  115 . The RAW file can be stored in the buffer unit  115  and the stored RAW file can be read again. However, after being stored in the buffer unit  115 , the RAW file may be moved to and stored in another storage medium (the RAW file may be deleted from the buffer unit  115 ). 
     The RAW file and the above still image file and moving image file are recorded in a storage medium  152  by a recording and reproducing unit  151  (recording and reproducing unit  151  and storage medium  152  can also be referred to as a storage unit). The storage medium  152  may be a built-in large-capacity semiconductor memory, a hard disk, a removable memory card, or the like. The recording and reproducing unit  151  can read these still image file, moving image file, and RAW file from the storage medium  152 . 
     The recording and reproducing unit  151  can write and read various files to and from an external storage or server via a communication unit  153 . The communication unit  153  can access the Internet or an external device via wireless or wired communication, by using a communication terminal  154 . 
     When a reproduction operation is started, the recording and reproducing unit  151  acquires a desired file from the storage medium  152  or via the communication unit  153  and reproduces the file. If the file to be reproduced is a RAW file, the recording and reproducing unit  151  stores the acquired RAW file in the buffer unit  115 . If the file to be reproduced is a still image file, the recording and reproducing unit  151  supplies the acquired still image file to a still image decompression unit  143 . If the file to be reproduced is a moving image file, the recording and reproducing unit  151  supplies the acquired moving image file to a moving image decompression unit  144 . 
     The RAW decompression unit  114  reads a RAW file stored in the buffer unit  115  and decodes and decompresses the compressed RAW file. The RAW file decompressed by the RAW decompression unit  114  is supplied to the development unit  110  and is input to the simple development unit  111  or the high-quality image development unit  112  in the development unit  110 . 
     The still image decompression unit  143  decodes and decompresses an input still image file and supplies the file to the display processing unit  122  as a still image to be reproduced. The moving image decompression unit  144  decodes and decompresses an input moving image file and supplies the file to the display processing unit  122  as a moving image to be reproduced. 
     Next, operation modes of the imaging apparatus  100  according to the present exemplary embodiment will be described in detail with reference to the drawings.  FIG. 2  is a state transition diagram illustrating transition of operation modes of the imaging apparatus  100 . Transition of these modes is performed in accordance with a user operation instruction input via the operation unit  162  or a control operation performed by the control unit  161 . In addition, transition of these modes is performed manually or automatically based on an operation. As illustrated in  FIG. 2 , four modes of a still image capturing mode ( 201 ), a still image reproduction mode ( 202 ), a moving image capturing mode ( 203 ), and a moving image reproduction mode ( 204 ) are suitably switched. The imaging apparatus  100  operates in one of these modes via an idle state ( 200 ). 
     Next, an operation in the still image capturing mode of the imaging apparatus  100  will be described. 
       FIG. 3  is a flowchart illustrating processing in a still image capturing mode according to the present exemplary embodiment. The flowchart in  FIG. 3  illustrates a processing procedure performed when the control unit  161  controls each processing block. More specifically, the processing procedure is performed when the control unit  161  expands a program stored in a read-only memory (ROM) of the control unit  161  to a random access memory (RAM) and executes the program. 
     In  FIG. 3 , in step S 300 , processing in the still image capturing mode is started. Next, in step S 301 , the control unit  161  determines whether the processing load of the imaging apparatus  100  is low. If the control unit  161  determines that the processing load is low (YES in step S 301 ), the operation proceeds to step S 320  and the imaging apparatus  100  shifts to an idle state with a frequency according to a load state. If not (NO in step S 301 ), the operation proceeds to step S 302 . For example, the processing load is high during a high-speed continuous image capturing operation. Thus, in such a case, the operation does not proceed to step S 320  but always proceeds to step S 302 . When a normal single image capturing operation is performed, between first and second capturing operations, for example, half of the operations proceeds to step S 320 . 
     In step S 302 , the camera control unit  104  controls operations of the imaging optical unit  101  and the image sensor unit  102  so that images are captured under suitable conditions. For example, a lens included in the imaging optical unit  101  is moved in accordance with a user instruction for zooming or focusing. In addition, the area read by the image sensor unit  102  is set in accordance with an instruction about the number of pixels to be captured. In addition, control operations such as focus adjustment and tracking control of a certain object are performed based on evaluation value information and object information supplied from the evaluation value calculation unit  105  and the recognition unit  131  as described below. 
     In step S 303 , the sensor signal processing unit  103  performs signal processing for pixel restoration on the converted electrical signal obtained by the image sensor unit  102 . Namely, by using values of neighboring pixels, the sensor signal processing unit  103  interpolates values of missing pixels and low-reliability pixels. In addition, the sensor signal processing unit  103  subtracts predetermined offset values. In the present exemplary embodiment, the image information output from the sensor signal processing unit  103  after step S 303  is referred to as a RAW image, which signifies a law (undeveloped) image. 
     Next, in step S 304 , the simple development unit  111  develops the RAW image. In this step S 304 , the control unit  161  changes over the switch unit  121  in the development unit  110  to select output of image information that has been developed by the simple development unit  111 . 
     The simple development unit  111  performs de-Bayer processing (de-mosaic processing), namely, color interpolation processing, on the RAW image, converts the RAW image into luminance and color difference (or primary color) signals, removes noise included in each signal, corrects optical distortion, and optimizes the image. Namely, the simple development unit  111  performs so-called development processing. Next, the development processing (simple development) performed by the simple development unit  111  will be described. By performing the processing in a lower amount of than that performed by the high-quality image development unit  112 , the simple development unit  111  realizes quicker and simpler development processing. For example, the simple development unit  111  limits the developed image size to 2 million pixels or less. Alternatively, the simple development unit  111  performs only limited processing for noise removal or optical distortion correction or omits performing such processing. Since the simple development unit  111  performs processing on a reduced image size or performs limited development processing, for example, the imaging apparatus  100  can achieve an image capturing operation of 2 million pixels and 60 frames per second with a smaller circuit scale and less power consumption. 
     The image information developed by the simple development unit  111  is supplied to the evaluation value calculation unit  105 . In step S 305 , the evaluation value calculation unit  105  calculates evaluation values such as those indicating the focus state and the exposure state, based on a luminance value, a contrast value, and the like included in the image information. The evaluation value calculation unit  105  may acquire an undeveloped RAW image and calculate evaluation values from the RAW image in a similar way. 
     In addition, the image information developed by the simple development unit  111  is also supplied to the recognition unit  131 . In step S 306 , the recognition unit  131  detects an object (a face, for example) from the image information and recognizes object information. For example, the recognition unit  131  detects presence or absence of a face in the image information. If a face exists, the recognition unit  131  detects the position of the face, authenticates a certain person, and outputs the result as information. 
     In addition, the image information developed by the simple development unit  111  is also supplied to the display processing unit  122 . In step S 307 , the display processing unit  122  forms a display image from the acquired image information and outputs the display image to the display unit  123  or an external display device to display the image. In the still image capturing mode, the display image presented by the display unit  123  is used for live view display (a through-the-lens image) so that the user can appropriately frame the object. The display image may be transmitted from the display processing unit  122  to another display device such as an external television via the video output terminal  124  so that the display device can present the display image. In addition, by using the evaluation value information and object information supplied from the evaluation value calculation unit  105  and the recognition unit  131 , the display processing unit  122  can present markings on focus areas on the display image and frames on the recognized face positions, for example. 
     In step S 308 , the control unit  161  determines whether an instruction for an image capturing operation is input from the user. If so (YES in step S 308 ), the operation proceeds to step S 310 . If not (NO in step S 308 ), the operation returns to step S 301  and preparatory operations for an image capturing operation and live view display are repeated. 
     If the control unit  161  determines an instruction for an image capturing operation has been input (YES in step S 308 ), the image information obtained by the development processing of the simple development unit  111  is supplied to the still image compression unit  141 . Namely, in step S 310 , the still image compression unit  141  performs high-efficiency coding (compression of the still image) on the acquired image information and creates a still image file. The still image compression unit  141  performs compression processing by using a known still image compression technique such as Joint Photographic Experts Group (JPEG). 
     Next, in step S 311 , the recording and reproducing unit  151  records the still image file in the storage medium  152 . 
     Next, in step S 312 , in response to the instruction for an image capturing operation (YES in step S 308 ), the RAW compression unit  113  acquires a RAW image that corresponds to the captured still image and that is output from the sensor signal processing unit  103  and performs high-efficiency coding (compression of the RAW image) on the RAW image, to convert the RAW image into a RAW file. The RAW file is stored in the buffer unit  115 . The RAW compression unit  113  performs the high-efficiency coding by using a known technique such as wavelet transform or differential coding. Either lossy coding or lossless coding may be used. Alternatively, the RAW compression unit  113  may omit compression of the RAW image. Namely, the RAW compression unit  113  may directly output the RAW image without compressing the RAW image. Regardless of whether the RAW image is compressed or not, according to the present exemplary embodiment, a RAW file that is not significantly deteriorated from the image information supplied from the sensor signal processing unit  103  and that can be restored as a high-quality image file is created. 
     In step S 313 , the recording and reproducing unit  151  records the RAW file in the storage medium  152 . Next, the operation proceeds to step S 301 . In steps S 311  and S 313 , the recording and reproducing unit  151  may transmit the still image file and/or the RAW file to an external storage via the communication unit  153  and the communication terminal  154  so that the still image file and/or the RAW file can be recorded in the external storage. 
     A flow of processing in the still image capturing mode according to the present exemplary embodiment has thus been described. 
     Next, configurations of a still image file and a RAW file according to the present exemplary embodiment will be described.  FIGS. 4A and 4B  illustrate configurations of a still image file and a RAW file. 
     A still image file  400  illustrated in  FIG. 4A  is recorded by the recording and reproducing unit  151  in a predetermined recording area of the storage medium  152 , for example. The still image file  400  includes a header portion  401 , a metadata portion  402 , and a compressed data portion  403 . The header portion  401  includes an identification code representing that this file is in a still image file format, for example. The compressed data portion  403  includes compressed data of the still image on which high-efficiency coding has been performed. 
     The metadata portion  402  includes information  404  about the name of the RAW file generated simultaneously with this still image file. In addition, the metadata portion  402  includes development status information  405  representing that this still image file has been obtained by the simple development unit  111  performing the simple development. In addition, the metadata portion  402  includes shooting metadata  406  including evaluation values and object information detected by the evaluation value calculation unit  105  and the recognition unit  131 , respectively, and information obtained during an image capturing operation by the imaging optical unit  101  and the image sensor unit  102  (for example, lens type identification information and sensor type identification information). In addition, while not illustrated, the metadata portion  402  may include an identification code of a storage medium in which the simultaneously-generated RAW file is recorded, path information about a folder in which the RAW file is recorded, and the like. 
     A RAW file  410  illustrated in  FIG. 4B  is recorded by the recording and reproducing unit  151  in a predetermined recording area of the storage medium  152 , for example. The RAW file  410  includes a header portion  411 , a metadata portion  412 , and a compressed data portion  413 . The header portion  411  includes an identification code representing that this file is in a RAW file format. The compressed data portion  413  includes RAW compressed data of the still image on which high-efficiency coding has been performed (or RAW image data of the still image that has not been compressed). 
     The metadata portion  412  includes information  414  about the name of the still image file generated simultaneously with this RAW file. In addition, the metadata portion  412  includes development status information  415  representing that this still image file has been obtained by the simple development unit  111  performing the simple development by. In addition, the metadata portion  412  includes shooting metadata  416  including evaluation values and object information detected by the evaluation value calculation unit  105  and the recognition unit  131 , and information obtained during an image capturing operation by the imaging optical unit  101  and the image sensor unit  102  (for example, lens type identification information and sensor type identification information). If data in the shooting metadata  416  is a common one with that in the shooting metadata  406 , the same data is used. In addition, while not illustrated, the metadata portion  412  may include an identification code of a storage medium in which the simultaneously-generated still image file is recorded and path information about a folder in which the still image file is recorded. Alternatively, the simultaneously-generated still image file itself may be formed as metadata and stored in the metadata portion  412 . 
     The above configurations of various files according to the present exemplary embodiment are examples. Other configurations compatible with standards such as Design rule for Camera File system (DCF) or Exchangeable Image File format (EXIF) may be used. 
     As described above, the simple development unit  111  of the imaging apparatus  100  according to the present exemplary embodiment performs live view display in the still image capturing mode until an instruction for an image capturing operation is input. In addition, in response to an instruction for an image capturing operation, the simple development unit  111  performs development processing to generate a still image file. For example, the simple development unit  111  limits the developed image size to 2 million pixels or less or only performs limited noise removal or optical distortion correction. Alternatively, the simple development unit  111  omits such processing. In this way, for example, the imaging apparatus  100  can perform development processing of 2 million pixels and 60 frames per second with a smaller circuit scale and less power consumption. In addition, as described above, the imaging apparatus  100  according to the present exemplary embodiment generates a RAW file in response to an instruction for capturing a still image. The RAW file is a high-quality image file that is not significantly deteriorated from the image information supplied from the sensor signal processing unit  103 . Generation of this file does not require development processing. Thus, it is possible to record the RAW file with a smaller circuit scale and less power consumption while increasing the number of image pixels or the speed of a continuous image capturing operation. 
     Next, step S 320  to which the processing proceeds as a result of determination in step S 301  in  FIG. 3 , will be described with reference to a flowchart in  FIG. 5 .  FIG. 5  illustrates a flowchart illustrating processing in an idle state according to the present exemplary embodiment. The flowchart in  FIG. 5  illustrates a processing procedure performed when the control unit  161  controls each processing block. More specifically, the processing procedure is performed when the control unit  161  expands a program stored in a ROM of the control unit  161  to a RAM and executes the program. 
     In  FIG. 5 , in step S 500 , processing in the idle state is started. Next, in step S 501 , the control unit  161  determines whether chasing development needs to be performed based on a user setting. If chasing development does not need to be performed (NO in step S 501 ), the operation proceeds to step S 502 . Otherwise (YES in step S 501 ), the operation proceeds to step S 520 . 
     In steps S 502 , S 503 , S 504 , and S 505 , the control unit  161  determines to shift to any of the modes  201  to  204  illustrated in  FIG. 2  in accordance with an instruction from the user or a mode setting. Next, the control unit  161  controls the imaging apparatus  100  to shift to a processing flow in the selected mode (in the selected one of the steps S 510 , S 511 , S 512 , and S 513 ). In step S 502 , if the control unit  161  determines that capturing of a still image is required (YES in step S 502 ), the operation proceeds to step S 510 . If not (NO in step S 502 ), the operation proceeds to step S 503 . In step S 503 , if the control unit  161  determines that reproduction of a still image is required (YES in step S 503 ), the operation proceeds to step S 511 . If not (NO in step S 503 ), the operation proceeds to step S 504 . In step S 504 , if the control unit  161  determines that capturing of a moving image is required (YES in step S 504 ), the operation proceeds to step S 512 . If not (NO in step S 504 ), the operation proceeds to step S 505 . In step S 505 , if the control unit  161  determines that reproduction of a moving image is required (YES in step S 505 ), the operation proceeds to step S 513 . 
     In the chasing development according to the present exemplary embodiment, an undeveloped RAW file that has been obtained by an image capturing operation and recorded in the buffer unit  115 , the storage medium  152 , or the like is read during an image capturing operation, in an interval between reproductions, in a sleep state, or the like. In the chasing development, high-quality image development processing is performed on the read RAW file, and a high-quality display image or a high-quality still image file is generated. Since the imaging apparatus  100  performs development processing on a previously-recorded RAW file as if the imaging apparatus  100  chases the RAW file, this development processing is called chasing development. While the chasing development according to the present exemplary embodiment can be performed on both the RAW file of a still image and the RAW file of a moving image, the description will be made based on the RAW file of a still image in what follows. 
     As described above, since a still image file generated during an image capturing operation is developed by the simple development unit  111 , the number of pixels is 2 million or less or part of the development processing is omitted. As a result, image quality is limited. While the captured image can be effectively used for general checking, the image may not be sufficient to check details of the image or to be printed. However, while the RAW file simultaneously generated with the still image has high image quality that has not significantly been deteriorated from the image information supplied from the sensor signal processing unit  103 , the RAW file cannot be displayed or printed promptly since the RAW file is data before development processing. Namely, development of the RAW file requires time. In addition, since the RAW file is not a widely-used file such as JPEG, reproduction environments in which the RAW file can be handled are limited. 
     Consequently, the chasing development according to the present exemplary embodiment can be used as an effective function. In the present exemplary embodiment, when the chasing development is performed, a RAW file that has already been recorded is read and development processing is performed by the high-quality image development unit  112  to form a high quality image, and the generated high-quality still image file is recorded in the storage medium  152  or the like. The imaging apparatus  100  performs the chasing development in a state of relatively low processing load in which the imaging apparatus  100  waits for a user operation, for example, in an interval between image capturing operations, in a reproduction mode, or in a sleep state. The chasing development can be designed to be performed not only manually by the user but also automatically by the control unit  161 . 
     In this way, after the chasing development, if high quality image reproduction is requested, for example, in display for checking of details or in a print out, development processing (reproduction output) is not every time delayed. In addition, such RAW files can be used in the same way as conventional still image files in general operation environments. 
     A set of a still image file and a RAW file is recorded in response to an instruction for capturing a single still image in the storage medium  152  or the like. When the chasing development is performed manually or automatically, in step S 520 , the control unit  161  determines whether the chasing development has been completed for each set of images. To perform such determination, for example, the control unit  161  refers to a flag included in the development status  405  stored in the metadata portion  402  of the still image file  400 . This flag indicates whether this still image file has already been processed by the simple development unit  111 . Alternatively, the control unit  161  may perform the determination by referring to the development status  415  in the RAW file  410 . Alternatively, the control unit  161  may perform the determination by separately preparing a table file representing a development processing status for a series of captured still images. 
     In step S 520 , if the control unit  161  determines that the chasing development has already been performed (YES in step S 520 ), the operation proceeds to step S 502 . If there is a still image on which the chasing development has not been performed yet, the operation proceeds to step S 521 . If a RAW file corresponding to the still image on which the chasing development has not been processed yet is buffered in the buffer unit  115  (YES in step S 521 ), the operation proceeds to step S 523 . If not (NO in step S 521 ), a corresponding RAW file is read from the storage medium  152  or the like (S 522 ). The RAW file read from the storage medium  152  or the like is temporarily stored in the buffer unit  115 . 
     Data in the buffer unit  115  is updated so that more-recent images captured in the still image capturing mode are preferably stored. Namely, the images are removed from the buffer unit  115  in chronological order. In this way, since the image captured most recently is always stored in the buffer unit  115 , step S 522  is skipped. Consequently, the image can be processed at high speed. In addition, if the chasing development is performed backward in time from the image captured most recently, since the image stored in the buffer is preferably processed, efficiency of the processing can be improved. 
     In step S 523 , the RAW decompression unit  114  decompresses the RAW file read from the buffer unit  115  or the storage medium  152  and restores the RAW image. 
     In step S 524 , the high-quality image development unit  112  develops the restored RAW image to a high quality image. Next, the high-quality image development unit  112  outputs the image to the display processing unit  122  and the still image compression unit  141  via the switch unit  121 . 
     The high-quality image development unit  112  performs de-Bayer processing (de-mosaic processing), namely, color interpolation processing, on the RAW image, converts the RAW image into luminance and color difference (or primary color) signals, removes noise included in each signal, corrects optical distortion, and optimizes the image. Namely, the high-quality image development unit  112  performs so-called development processing. The size (the number of pixels) of the developed image generated by the high-quality image development unit  112  is that of a full-size image read by the image sensor unit  102 , or a size set by the user. Thus, the quality is significantly higher than that of an image developed by the simple development that limits the number of pixels to 2 million or less. 
     Since the high-quality image development unit  112  performs each processing more accurately than the simple development unit  111 , a developed image having higher quality can be obtained. However, a larger processing load is required. The high-quality image development unit  112  according to the present exemplary embodiment does not perform real-time development processing simultaneously with an image capturing operation but performs development processing after an image capturing operation when there is sufficient time. As a result, increase in circuit scale or power consumption can be reduced. 
     The image information developed by the high-quality image development unit  112  is supplied to the still image compression unit  141 . In step S 525 , the still image compression unit  141  performs high-efficiency coding (compression of the still image) on the acquired image information and generates a high-quality still image file. The still image compression unit  141  performs compression processing by using a known technique such as JPEG. 
     Next, in step S 526 , the recording and reproducing unit  151  records the high-quality still image file in the storage medium  152  or the like. Next, the operation proceeds to step S 502 . If there are still images on which the chasing development has not been performed yet, similar processing can repeatedly be performed for each of the images. 
     The still image file recorded in step S 526  has a file configuration as illustrated in the still image file  400  in  FIG. 4A . The still image file  400  includes the header portion  401 , the metadata portion  402 , and the compressed data portion  403 . The header portion  401  includes the identification code representing that this file is in a still image file format, for example. The compressed data portion  403  includes compressed data of the still image on which high-efficiency coding has been performed. 
     The metadata portion  402  includes the information  404  about the name of the RAW file from which this still image file has been generated. In addition, the metadata portion  402  includes the development status information  405  representing that this still image file has been developed by the high-quality image development by the high-quality image development unit  112 . Further, the metadata portion  402  includes shooting metadata  406  including evaluation values and object information that are extracted from the metadata of the original RAW file and detected by the evaluation value calculation unit  105  and the recognition unit  131 , and information obtained during an image capturing operation by the imaging optical unit  101  and the image sensor unit  102 . 
     The recording and reproducing unit  151  gives the same file name as that of the previously-created still image file that is obtained after the simple development and that is recorded simultaneously with the original RAW file, to the new still image file recorded in step S 526  after the high-quality image development. Namely, the recording and reproducing unit  151  overwrites the previously-created still image file with the newly-created still image file. In other words, the previously-created still image file obtained after the simple development is deleted. The recording and reproducing unit  151  updates the RAW file on which the chasing development has been performed, by writing information representing that the high-quality image development (or chasing development) has already been completed in the development status  415  in the metadata portion  412 . Instead of overwrite recording, the recording and reproducing unit  151  may record the new file with a nearly similar file name. For example, the new file may be recorded as a different file whose file name has been changed only partially (for example, the extension or the character of the end portion may be changed) and the original file may be deleted. The original file may of course be saved if a sufficient storage capacity is available. 
     Thus, the imaging apparatus  100  according to the present exemplary embodiment performs the chasing development in a state of relatively low processing load (in an idle state) in which the imaging apparatus  100  waits for a user operation, for example, in an interval between image capturing operations, in a reproduction mode, or in a sleep state. In addition, the still image file obtained by the simple development during an image capturing operation is replaced by the still image file obtained by the high-quality image development using the RAW file. The moving image file obtained by the simple development during an image capturing operation is also replaced by the moving image file obtained by the high-quality image development using the RAW file. In this way, even if high quality image reproduction is requested, for example, in display for checking of details, or in a print out, development processing (reproduction output) is not every time delayed. In addition, such RAW files become usable in the same way as conventional still image files in general operation environments. 
     Next, an operation in the still image reproduction mode of the imaging apparatus  100  will be described. 
       FIG. 6  is a flowchart illustrating processing in the still image reproduction mode according to the present exemplary embodiment. The flowchart in  FIG. 6  illustrates a procedure performed when the control unit  161  controls each processing block. More specifically, the procedure is performed when the control unit  161  expands a program stored in a ROM of the control unit  161  to a RAM and executes the program. 
     In  FIG. 6 , in step S 600 , processing in the still image reproduction mode is started. Next, in step S 601 , the control unit  161  determines whether the processing load of the imaging apparatus  100  is low. If the control unit  161  determines that the processing load is low (YES in step S 601 ), the operation proceeds to step S 610  and the imaging apparatus  100  shifts to an idle state with a frequency according to the load state. If not (NO in step S 601 ), the operation proceeds to step S 602 . For example, when the imaging apparatus  100  is waiting for a user operation such as a reproduction instruction, the processing load is low. Thus, in such a case, the operation proceeds to step S 610 . If reproduction of a still image has already been instructed or a still image is being reproduced by a user operation, the operation proceeds to step S 602 . 
     In step S 602 , the control unit  161  determines whether the user has given the imaging apparatus  100  an instruction for enlarging display of a still image to be reproduced. If so (YES in step S 602 ), the operation proceeds to step S 603 . If not (NO in step S 602 ), the operation proceeds to step S 620 . 
       FIG. 7  illustrates display modes including an enlarged display mode.  FIGS. 7A to 7C  illustrate display processing in the still image reproduction mode according to the present exemplary embodiment. 
     A display  700  in  FIG. 7A  is an example in which the display unit  123  displays six reduced images  701 . A display  710  in  FIG. 7B  is an example in which the display unit  123  displays the whole of a certain image  711 . This display state is considered as normal display. A display  720  in  FIG. 7C  is an example in which the display unit  123  displays an image  721  which is an enlarged area of a certain image. For example, generally, a part of an object image is enlarged as illustrated in the display example  720  immediately after an image capturing operation to determine whether focusing has been appropriately performed. 
     If enlarged display is performed as illustrated in the display example  720  (YES in step S 602 ), the operation in  FIG. 6  proceeds from step S 602  to step S 603 . If reduced display is performed as illustrated in the display example  700  (NO in step S 602 ), the operation proceeds from step S 602  to step S 620 . Regarding the display example  710 , if the number of pixels displayed by the display unit  123  is the number of pixels of a still image file obtained by the simple development (2 million pixels or less in the above example), the image can be displayed at the same or a reduced magnification. Thus, the operation proceeds from step S 602  to step S 620 . 
     In step S 620 , the recording and reproducing unit  151  reads the reproduction target still image file from the storage medium  152  or the like. Next, in step S 621 , the still image decompression unit  143  decodes and decompresses the still image file. Next, in step S 608 , the display processing unit  122  outputs the display image to the display unit  123  in a format illustrated in  FIGS. 7A-7C . 
     If the number of pixels of the still image file obtained by the simple development (2 million pixels or less in the above example) is sufficient to display an image, the still image file developed by the simple development unit  111  can be displayed with sufficient image quality. Of course, if the still image file has been developed by the high-quality image development unit  112 , the still image file has sufficient image quality for display. 
     In contrast, if the enlarged display is performed, the number of pixels of a still image file obtained by the simple development (2 million pixels or less in the above example) may not be sufficient to display an image. Namely, if the still image file developed by the simple development is used for display, sharpness is decreased. 
     Thus, if enlarged display is presented, in step S 603 , the control unit  161  determines whether the still image file of the reproduction and display target image has been developed by the high-quality image development unit  112 . In order to make such a determination, for example, the control unit  161  refers to a flag included in the development status  405  stored in the metadata portion  402  of the still image file  400 . This flag indicates whether this still image file has already been processed by the simple development unit  111 . Alternatively, the control unit  161  may make the determination by referring to the development status  415  in the RAW file  410 . Alternatively, the control unit  161  may make the determination by separately preparing a table file representing a development processing status for a series of captured still images. 
     In step S 603 , if the control unit  161  determines that the high-quality image development has been performed (YES in step S 603 ), the control unit  161  determines that the still image file is a high-quality still image file that can be displayed with sufficient image quality even if enlarged. Thus, in such a case (YES in step S 603 ), the operation proceeds to step S 620  and the recording and reproducing unit  151  reads the corresponding high-quality still image file from the storage medium  152  or the like, and reproduces and displays the still image file. As described above, if the still image file has already been developed by the high-quality image development unit  112 , the still image file can be displayed with high image quality through processing after step S 620 . 
     In step S 603 , if the control unit  161  does not determine that the high-quality image development has been performed (NO in step S 603 ), the control unit  161  determines that the still image file has been developed by the simple development unit  111 . Thus, in such a case (NO in step S 603 ), the operation proceeds to step S 604  and the imaging apparatus  100  performs high-quality image development (the above chasing development). 
     Next, in step S 604 , if the RAW file corresponding to the reproduction target still image is buffered in the buffer unit  115  (YES in S 604 ), the operation proceeds to step S 606 . If not (NO in S 604 ), the operation proceeds to step S 605  and the corresponding RAW file is read from the storage medium  152  or the like. The RAW file read from the storage medium  152  or the like is temporarily stored in the buffer unit  115 . 
     Data in the buffer unit  115  is updated so that more-recent images captured in the still image capturing mode are preferably stored. Namely, the images are removed from the buffer unit  115  in chronological order. In this way, since the image captured most recently is always stored in the buffer unit  115 , step S 605  is skipped. Consequently, the image can be displayed promptly. 
     Next, in step S 606 , the RAW decompression unit  114  decodes and decompresses the RAW file read from the buffer unit  115  or the storage medium  152  and restores the RAW image. 
     Next, in step S 607 , the restored RAW image is developed by the high-quality image development unit  112  to a high quality image and the developed image is output to the display processing unit  122  via the switch unit  121 . Next, in step S 608 , the display processing unit  122  outputs an enlarged image as illustrated in  FIG. 7C  to the display unit  123 . 
     The high-quality image development unit  112  performs de-Bayer processing (de-mosaic processing), namely, color interpolation processing, on the RAW image, converts the RAW image into luminance and color difference (or primary color) signals, removes noise included in each signal, corrects optical distortion, and optimizes the image. Namely, the high-quality image development unit  112  performs so-called development processing. The size (the number of pixels) of the developed image generated by the high-quality image development unit  112  is that of a full-size image read by the image sensor unit  102 , or a size set by the user. Thus, the quality is significantly higher than that of an image developed by the simple development that limits the number of pixels to 2 million or less. Thus, the still image developed by the high-quality image development unit  112  can be displayed with sufficient image quality in response to an enlarged display request. 
     After the display in step S 608  is stopped, the operation returns to step S 601 . If the control unit  161  determines that the processing load is low (YES in step S 601 ), the operation proceeds to step S 610  and the imaging apparatus  100  shifts to an idle state. In such a case, the image is processed in accordance with the above flowchart in  FIG. 5 . 
     It is assumed that the high-quality image development after step S 604  in  FIG. 6  is performed when the chasing development has not yet been performed, for example, immediately after an image capturing operation, as described above. In the present exemplary embodiment, the chasing development on a still image is gradually completed in a relatively low processing load state in which the imaging apparatus  100  waits for a user operation, for example, in an interval between image capturing operations, in a reproduction mode, or in a sleep state, and the still image file developed by the simple development is naturally replaced by the still image file developed by the high-quality image development. The more images are replaced, the less high-quality image development operation after step S 604  is performed. Namely, since a high quality image can always be output promptly, operability can be improved further. 
     As described above, if the RAW file is stored in the buffer unit  115 , since step S 605  can be skipped, the image can be displayed promptly. Thus, in the case of the display examples  700  and  710  in  FIG. 7 , to prepare for an enlarged display instruction, RAW files corresponding to the images  701  and  711  may be previously read from a storage medium and moved to the buffer unit  115  so that as many RAW files as possible are stored in the buffer unit  115 . By causing the recording and reproducing unit  151  to read a corresponding RAW file from the storage medium  152  or the like and causing the buffer unit  115  to buffer the corresponding RAW file prior to an instruction for enlarged display, the image can be displayed more promptly in response to an instruction for the enlarged display as illustrated by the display example  720 . 
     Next, an operation in the moving image capturing mode of the imaging apparatus  100  will be described. 
       FIG. 8  is a flowchart illustrating processing in the moving image capturing mode according to the present exemplary embodiment. The flowchart in  FIG. 8  illustrates a procedure performed when the control unit  161  controls each processing block. More specifically, the procedure is performed when the control unit  161  expands a program stored in a ROM of the control unit  161  to a RAM and executes the program. 
     In  FIG. 8 , in step S 800 , processing in the moving image capture mode is started. Next, in step S 801 , the control unit  161  determines whether the processing load of the imaging apparatus  100  is low. If the control unit  161  determines that the processing load is low (YES in step S 801 ), the operation proceeds to step S 820  and the imaging apparatus  100  shifts to an idle state with a frequency according to the load state. If not (NO in step S 801 ), the operation proceeds to step S 802 . For example, the processing load is high when a moving image including many pixels whose horizontal resolution is on the order of 4,000 (4K) pixels is set or when a moving image with a high frame rate such as 120 frames (120P) per second is set. In such a case, the operation does not proceed to step S 820  but always proceeds to step S 802 . If the imaging apparatus  100  captures a moving image whose pixel number is lower than a predetermined value or whose frame rate is lower than a predetermined rate, for example, half of the operations proceeds to step S 820  between a first frame and a second frame of a moving image. 
     In step S 802 , the camera control unit  104  controls operations of the imaging optical unit  101  and the image sensor unit  102  so that a moving image is captured under suitable conditions. For example, a lens included in the imaging optical unit  101  is moved in accordance with a user instruction for zooming or focusing. In addition, the area read by the image sensor unit  102  is set in accordance with an instruction about the number of pixels. Further, control operations such as focus adjustment and tracking of a certain object are performed based on evaluation value information and object information supplied from the evaluation value calculation unit  105  and the recognition unit  131  as described below. 
     In step S 803 , the sensor signal processing unit  103  performs signal processing for pixel restoration on the converted electrical signal obtained by the image sensor unit  102 . Namely, by using values of neighboring pixels, the sensor signal processing unit  103  interpolates values of missing pixels and low-reliability pixels. In addition, the sensor signal processing unit  103  subtracts predetermined offset values. In the present exemplary embodiment, the image information output from the sensor signal processing unit  103  after step S 803  is referred to as a RAW image (in particular, a RAW moving image), which signifies a law (undeveloped) moving image. 
     Next, in step S 804 , the simple development unit  111  develops the RAW image. In this step S 804 , the control unit  161  changes over the switch unit  121  in the development unit  110  to select output of image information that has been developed by the simple development unit  111 . 
     The simple development unit  111  performs de-Bayer processing (de-mosaic processing) on the RAW moving image that forms the frames of a moving image, converts the RAW moving image into luminance and color difference (or primary color) signals, removes noise included in each signal, corrects optical distortion, and optimizes the image. Namely, the simple development unit  111  performs so-called development processing. Next, the development processing (simple development) performed on the moving image by the simple development unit  111  will be described. For example, the simple development unit  111  limits the developed image size to 2 million pixels or less of a high definition (HD) size. Alternatively, the simple development unit  111  only performs limited noise removal or optical distortion correction. Alternatively, the simple development unit  111  omits performing such processing. In this way, the simple development unit  111  realizes quicker and simpler development. Since the simple development unit  111  performs processing on an image of reduced size or performs limited development processing, the imaging apparatus  100  can capture a moving image of a HD size or the like at high speed with a smaller circuit scale and less power consumption. 
     The image information developed by the simple development unit  111  is supplied to the evaluation value calculation unit  105 . In step S 805 , the evaluation value calculation unit  105  calculates evaluation values such as the focus state and the exposure state, based on a luminance value, a contrast value, and the like included in the image information. The evaluation value calculation unit  105  may acquire the RAW moving image before the development processing is performed and calculate evaluation values from the RAW moving image in a similar way. 
     In addition, the image information developed by the simple development unit  111  is also supplied to the recognition unit  131 . In step S 806 , the recognition unit  131  detects an object (a face, for example) from the image information and recognizes object information. For example, the recognition unit  131  detects presence or absence of a face in the image information. If a face exists, the recognition unit  131  detects the position of the face, authenticates a certain person, and outputs the result as information. 
     In addition, the image information developed by the simple development unit  111  is also supplied to the display processing unit  122 . In step S 807 , the display processing unit  122  forms a display image from the acquired image information and outputs the display image to the display unit  123  or an external display device to display the image. In the moving image capturing mode, the display image presented by the display unit  123  is used for checking the display so that the user can appropriately frame an object. More specifically, as a usage unique to capturing of a moving image, not only before the recording of a captured moving image is started (in a standby state) but also while the recording of a moving image is being performed (during REC), the display image is used for live view display so that the user can appropriately frame an object. The display image may be transmitted from the display processing unit  122  to another display device such as an external television via the video output terminal  124  so that the display device can present the display image. In addition, by using the evaluation value information and object information supplied from the evaluation value calculation unit  105  and the recognition unit  131 , the display processing unit  122  can display markings on focus areas of the display image and frames on the recognized face positions, for example. 
     In step S 808 , the control unit  161  determines whether the captured moving image is being recorded (during REC) in response to a recording start instruction from the user. If so (YES in step S 808 ), the operation proceeds to step S 810 . If not (NO in step S 808 ), namely, if the imaging apparatus  100  is in a standby state (NO in step S 808 ), the operation returns to step S 801 , and the image capturing operation and live view display before the start of recording of a moving image are repeated. 
     In step S 810 , of the moving images captured in step S 808 , the moving image compression unit  142  compresses the moving image recorded from the start of the recording to the end of the recording frame by frame. In addition, simultaneously with capturing of a moving image, audio information input via a microphone (not illustrated) is acquired. However, description of the audio information by using a drawing will be omitted. The moving image compression unit  142  also compresses the audio information corresponding to the moving image. 
     The moving image compression unit  142  performs high-efficiency coding (compression of the moving image) on the acquired moving image information on which the simple development has been performed, and the audio information to generate a moving image file. By using a known moving image compression technique such as MPEG-2, H.264, or H.265, the moving image compression unit  142  performs the compression processing. 
     In step S 811 , the recording and reproducing unit  151  records the moving image file in the storage medium  152 . 
     The sensor signal processing unit  103  supplies the RAW moving image of the period corresponding to the period of the moving image recorded in step S 808 , to the RAW compression unit  113 . In step S 812 , the RAW compression unit  113  performs high-efficiency coding (RAW compression) on the RAW moving image representing the same scene as that represented by the recorded moving image and converts the RAW moving image into a RAW file (RAW moving image file). The RAW moving image file is stored in the buffer unit  115 . The RAW compression unit  113  performs the high-efficiency coding by using a known technique such as wavelet transform or differential coding, which may be lossy coding or lossless coding. Alternatively, the RAW compression performed by the RAW compression unit  113  may be omitted. Namely, the RAW compression unit  113  may directly output the RAW moving image without compressing the RAW moving image. Regardless of whether the RAW moving image is compressed or not, in the present exemplary embodiment, a RAW moving image file can be created that is not significantly deteriorated from the image information supplied from the sensor signal processing unit  103  and that can be restored as a high-quality image file. 
     In step S 813 , the recording and reproducing unit  151  records the RAW moving image file in the storage medium  152 . Next, the operation proceeds to step S 801 . Alternatively, in steps S 811  and S 813 , the recording and reproducing unit  151  may transmit the moving image file and/or the RAW moving image file to an external storage via the communication unit  153  and the communication terminal  154  so that the moving image file and/or the RAW moving image file can be recorded in the external storage. 
     A flow of processing in the moving image capturing mode according to the present exemplary embodiment has thus been described. 
     Next, configurations of a moving image file and a RAW moving image file according to the present exemplary embodiment will be described.  FIGS. 9A and 9B  illustrate configurations of a moving image file and a RAW moving image file. 
     A moving image file  900  illustrated in  FIG. 9A  is recorded by the recording and reproducing unit  151  in a predetermined recording area of the storage medium  152 , for example. The moving image file  900  includes a header portion  901 , a metadata portion  902 , and a compressed data portion  903 . The header portion  901  includes an identification code representing that this file is in a moving image file format. The compressed data portion  903  includes compressed data of the audio and the moving image on which high-efficiency coding has been performed. 
     The metadata portion  902  includes information  904  about the name of the RAW moving image file generated simultaneously with this moving image file. In addition, the metadata portion  902  includes development status information  905  representing that this moving image file has been developed by the simple development unit  111  performing the simple development. Further, the metadata portion  902  includes shooting metadata  906  including evaluation values and object information detected by the evaluation value calculation unit  105  and the recognition unit  131 , and information obtained during an image capturing operation performed by the imaging optical unit  101  and the image sensor unit  102  (for example, lens type identification information and sensor type identification information). Furthermore, while not illustrated, the metadata portion  902  may include an identification code of a storage medium in which the simultaneously-generated RAW moving image file is recorded, and path information about a folder in which the image file is recorded. 
     A RAW moving image file  910  illustrated in  FIG. 9B  is recorded by the recording and reproducing unit  151  in a predetermined recording area of the storage medium  152 , for example. The RAW moving image file  910  includes a header portion  911 , a metadata portion  912 , and a compressed data portion  913 . The header portion  911  includes an identification code representing that this file is in a RAW moving image file format. The compressed data portion  913  includes RAW compressed data of the moving image on which high-efficiency coding has been performed (or may include RAW image data of the moving image that has not been compressed). 
     The metadata portion  912  includes information  914  about the name of the moving image file generated simultaneously with this RAW moving image file. Further, the metadata portion  912  includes development status information  915  representing that this moving image file has been developed by the simple development unit  111  performing the simple development. In addition, the metadata portion  912  includes shooting metadata  916  including evaluation values and object information detected by the evaluation value calculation unit  105  and the recognition unit  131 , and information obtained during an image capturing operation by the imaging optical unit  101  and the image sensor unit  102  (for example, lens type identification information and sensor type identification information). If data in the shooting metadata  916  is a common one with that in the shooting metadata  906 , the same data is used. Further, while not illustrated, the metadata portion  912  may include an identification code of a storage medium in which the simultaneously-generated moving image file is recorded, and path information about a folder in which the moving image file is recorded. Alternatively, the simultaneously-generated moving image file may entirely be formed as metadata and stored in the metadata portion  912 . Alternatively, part (a head frame, for example) of the simultaneously generated moving image file may be extracted and formed as metadata and stored in the metadata portion  912 . 
     The above configurations of various files according to the present exemplary embodiment are only examples. Other configurations compatible with standards such as DCF, Advanced Video Codec High Definition (AVCHD), or Material eXchange Format (MXF) may be used. 
     The simple development unit  111  in the imaging apparatus  100  according to the present exemplary embodiment displays an image captured in the moving image capture mode (live view display) and performs development processing on a moving image file generated during an image capturing operation, as described above. The simple development unit  111  performs the processing in a lower amount than that required by the high-quality image development unit  112 , for example, by limiting the developed image size to 2 million pixels or less, by only performing limited noise removal or optical distortion correction, or by omitting such processing. In this way, the simple development unit  111  can develop, for example, a moving image of a HD size with a smaller circuit scale and less power consumption. Further, as described above, in addition to a moving image file, the imaging apparatus  100  according to the present exemplary embodiment generates a RAW moving image file corresponding to the recording period of the moving image. The RAW moving image file is not significantly deteriorated from the image information supplied from the sensor signal processing unit  103 , however, no development processing is required for generating this file. Thus, even if the image pixel number is increased to 4K, or 8K (the horizontal resolution is on the order of 8,000 pixels) or the frame rate is increased to 120 frames per second (120P), the RAW moving image file can be recorded with a smaller circuit scale and less power consumption. 
     Next, an operation of the imaging apparatus  100  in the moving image reproduction mode will be described. 
       FIG. 10  is a flowchart illustrating processing in the moving image reproduction mode according to the present exemplary embodiment. The flowchart in  FIG. 10  illustrates a procedure performed when the control unit  161  controls each processing block. More specifically, the procedure is performed when the control unit  161  expands a program stored in a ROM of the control unit  161  to a RAM and executes the program. 
     In  FIG. 10 , in step S 1000 , processing in the moving image reproduction mode is started. Next, in step S 1001 , the control unit  161  determines whether the processing load of the imaging apparatus  100  is low. If the control unit  161  determines that the processing load is low (YES in step S 1001 ), the operation proceeds to step S 1010  and the imaging apparatus  100  shifts to an idle state with a frequency according to the loading state. If not (NO in step S 1001 ), the operation proceeds to step S 1002 . For example, when the imaging apparatus  100  is waiting for a user operation such as a reproduction instruction, the processing load is low. Thus, in such a case, the operation proceeds to step S 1010 . If reproduction of a moving image has already been instructed and a moving image is being reproduced by a user operation, the operation proceeds to step S 1002 . 
     In step S 1002 , the control unit  161  determines whether the user has given an instruction for temporarily stopping (pause) of reproduction of the moving image. If not (NO in step S 1002 ), the operation proceeds to step S 1003  to continue reproduction of the moving image. 
     In step S 1003 , the recording and reproducing unit  151  reads a moving image file to be reproduced, from the storage medium.  152  or the like. Next, in step S 1004 , the moving image decompression unit  144  decodes and decompresses frames of the moving image file one by one. Next, in step S 1005 , the display processing unit  122  outputs the reproduced display image of the moving image to the display unit  123 . 
     In step S 1002 , if the control unit  161  determines that the user has given an instruction for temporarily stopping (pause) of reproduction of the moving image (YES in step S 1002 ), the control unit  161  temporarily stops reproduction and display of the moving image and the operation proceeds to step S 1020  to display as a still image the frame corresponding to the position at which the pause instruction has been given. In the pause state, since the still image is displayed, the user can view quality of the details of the image more easily than that of the moving image in motion. In addition, it is more likely that an instruction for enlarged display during a pause operation is received. Therefore, to display an image with higher image quality than a moving image file developed by the simple development, in step S 1020 , the recording and reproducing unit  151  reproduces the RAW image frame corresponding to the frame being displayed in the pause operation, of the RAW moving image file corresponding to the moving image file being reproduced. In this step S 1020 , if the reproduction-target RAW moving image file is buffered in the buffer unit  115 , the recording and reproducing unit  151  reads the RAW moving image file from the buffer unit  115 . If not, the recording and reproducing unit  151  reads the RAW moving image file from the storage medium  152  or the like. The RAW moving image file read from the storage medium  152  or the like is temporarily stored in the buffer unit  115 . 
     Next, in step S 1021 , the RAW decompression unit  114  decodes and decompresses the RAW moving image file read from the buffer unit  115 , the storage medium  152 , or the like, to restore the RAW moving image. In step S 1022 , the high-quality image development unit  112  develops the restored RAW moving image to a high-quality moving image. 
     The imaging apparatus  100  can capture as a new still image file the high-quality still image that has been developed as a high quality image from the RAW moving image file and that corresponds to the frame displayed in the pause operation. In step S 1023 , the control unit  161  determines whether the user has given an instruction for capturing as a still image the displayed image in the pause operation. If not (NO in step S 1023 ), the still image developed as a high quality image from the RAW moving image file is supplied to the display processing unit  122 . Next, in step S 1005 , the display processing unit  122  outputs the developed display image of the high-quality still image, to the display unit  123 . In this way, the image displayed when the moving image file is temporarily stopped is replaced by the display image of the still image developed as a high quality image from the RAW image. 
     In step S 1023 , if the control unit  161  determines that the user has given an instruction for capturing a still image (YES in step S 1023 ), the image information developed by the high-quality image development unit  112  in step S 1022  is supplied to the still image compression unit  141 . In step S 1024 , the still image compression unit  141  performs high-efficiency coding (compression of the still image) on the image information acquired by the capturing and generates a high-quality still image file. The still image compression unit  141  may perform compression processing by using a known technique such as JPEG. 
     After the recording and reproducing unit  151  records the high-quality still image file in the storage medium  152  or the like in step S 1025 , the operation proceeds to step S 1005 . The still image developed as a high quality image from the RAW moving image file is supplied to the display processing unit  122 . Next, in step S 1005 , the display processing unit  122  outputs the display image of the still image developed as a high quality image to the display unit  123 . In this way, the image displayed when the moving image file is temporarily stopped is replaced by the display image of the still image developed as a high quality image from the RAW image. 
     The high-quality still image file generated by the still image compression unit  141  in step S 1024  has a configuration as illustrated by the configuration of the still image file  400  in  FIG. 4A . The metadata portion  402  stores the name of the RAW moving image file from which the high-quality still image file has been generated, as the information  404  about the RAW file. Further, information about the time at which the frame has been captured as the still image is stored as the shooting metadata  406 . The information can indicate the position of the frame in the RAW moving image file. Alternatively, the frame in the RAW moving image file may be extracted as a still image, and the RAW file  410  of the new still image serving as a counterpart may be created at this point. Regarding generation of the RAW file of the still image, the still image file and the RAW file are generated based on the method as described with steps S 310  to S 313  in the above still image capturing mode. 
     The display in step S 1005  is performed per frame. During reproduction of the moving image, the operation returns to step S 1001  to display the next frame. In step S 1001 , if the control unit  161  determines that the processing load is low (YES in step S 1001 ), and the imaging apparatus  100  shifts to an idle state S 1010 , the operation is processed in accordance with the above flowchart in  FIG. 5 . 
     Thus, to reproduce a moving image easily and without delay, the imaging apparatus  100  according to the present exemplary embodiment uses a moving image file recorded during an image capturing operation. In a pause state, the imaging apparatus  100  can replace the moving image with a still image developed as a high quality image from the RAW file of the moving image and display the still image. In addition, this high-quality still image can easily be captured as a still image file. 
     Further, it is assumed that the high-quality image development after step S 1020  in  FIG. 10  is performed when chasing development has not yet been performed, at timing immediately after an image capturing operation. In the present exemplary embodiment, the imaging apparatus  100  gradually completes the chasing development on a moving image in a relatively low processing load state in which the imaging apparatus  100  waits for a user operation, for example, in an interval between image capturing operations, in a reproduction mode, or in a sleep state. The moving image file generated by the simple development is naturally replaced with the moving image file generated by the high-quality image development. The more images are replaced, the less high-quality image development operation after step S 1020  is performed. Namely, since a high-quality image can always be output promptly, operability can be improved further. 
     While the present exemplary embodiment has thus been described, the present invention is not limited thereto. According to the present invention, within the technical concept of the present invention, various changes are applicable as needed depending on related circuit modes. 
     OTHER EMBODIMENTS 
     Embodiments of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions recorded on a storage medium (e.g., non-transitory computer-readable storage medium) to perform the functions of one or more of the above-described embodiment(s) of the present invention, and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more of a central processing unit (CPU), micro processing unit (MPU), or other circuitry, and may include a network of separate computers or separate computer processors. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD) (trademark), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2013-053244 filed Mar. 15, 2013 and No. 2013-053245 filed Mar. 15, 2013, which are hereby incorporated by reference herein in their entirety.