Patent Publication Number: US-2002008771-A1

Title: Digital camera and image processing apparatus

Description:
[0001] This application is based on application No. 2000-111704 filed in Japan, the contents of which are hereby incorporated by reference. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] 1. Field of the Invention  
       [0003] The present invention relates to a technique of performing a process on an image captured by a digital camera or the like. The digital camera may be a digital still camera or a digital movie camera.  
       [0004] 2. Description of the Background Art  
       [0005] Conventionally, an image process is performed on an image captured by a digital camera or the like to correct the hue and contrast of the image. A technique of dividing an image into a plurality of areas at the time of image correction, determining an image pickup environment from brightness and a color average value of each divided area, and correcting the image more properly by using the result of determination is also proposed.  
       [0006] On the other hand, at the time of capturing an image, metering process for measuring brightness of an object is conducted to determine exposure parameters such as an F-number (aperture) and exposure time. The types of metering are broadly classified into a method of metering the brightness only in a specific area in an image capturing range (hereinbelow, called “spot metering”) and a method of metering the brightness in a plurality of areas within an image capturing range (hereinbelow, called “multi-area metering”). There is a case that the multi-area metering uses a method of determining image capturing environment by using measurement values in the respective areas. As described above, in a digital camera, various measurement results and determination results related to metering are obtained at the time of determining exposure parameters.  
       [0007] For example, as described in Japanese Patent Application Laid-Open No. 10-191246(1998), which corresponds to U.S. Pat. No. 6,011,547, a technique of utilizing information used for determining exposure parameters to correct the captured image has been proposed. The publication discloses that a process performed in the multi-area metering or parameters used for a process are stored and the information is utilized to make an image correction intended by the user.  
       [0008] There is, however, a variety of information to determine exposure parameters. It cannot be said that information provided at the time of image capturing is sufficiently utilized when the intention of the user is reflected by simply using a process or parameters in multi-area metering. Particularly, the metering provides information exerting a large influence on a process of correcting an image. Further, a metering result and a determination result obtained in the case of multi-area metering have commonality with information used to correct an image captured.  
       SUMMARY OF THE INVENTION  
       [0009] The present invention is directed to a digital camera. According to the present invention, the digital camera comprises: an image pickup device for capturing an image of a subject; an exposure determining element for determining exposure parameters in image capturing; a selector for selecting a metering process for determining the exposure parameters; and a corrector for correcting the image through a correcting process according to a type of the metering process selected by the selector.  
       [0010] Preferably, the corrector is operable to correct the image on the basis of values of pixels correcting to a specific area within an image capturing range, when the metering process selected for the image is a first metering type in which brightness in the specific area is weighted within the image capturing range.  
       [0011] The corrector may be operable to correct the image on the basis of either a result of the metering process or information lead from the result of the metering process, when the metering process selected for capturing the image is a second metering type in which a plurality of areas within the image capturing range are metered.  
       [0012] In a preferred embodiment of the present invention, the exposure determining element determines a relation between a distribution of brightness in the image and the subject on the basis of the result of the metering process to make scene determination, and the corrector corrects the image on the basis of a result of the scene determination.  
       [0013] The present invention is also directed to an apparatus for processing an image. According to the present invention, the apparatus comprises: a first element for determining a metering type used in capturing the image from image data including the image and determining a correcting process in accordance with the metering type; and a second element for correcting the image through the correcting process.  
       [0014] The digital camera and/or the apparatus may operate in accordance with software programs which are stored in storage or installed through a network.  
       [0015] In an aspect of the present invention, an image processing system comprises: an image camera for capturing an image of a subject; a metering device for metering the subject for exposure control at capturing, and provided with a plurality of metering processes; a program storage for storing a plurality of image-correction programs previously related, respectively; a selector for selecting a metering process among the plurality of metering processes to activate the metering device in accordance with the metering process selected: and an image-corrector for correcting the image according to an image-correction program previously related to the metering process.  
       [0016] In another aspect of the present invention, an image processing system comprising: an image camera for capturing an image of a subject; a metering device for metering the subject for exposure control to generate a metering information; and an image-corrector for correcting the image in response to the metering information obtained in the metering device.  
       [0017] It is therefore an object of the invention to overcome the problems caused in the background arts.  
       [0018] It is another object of the invention to make an appropriate image correction by effectively utilizing information obtained in metering process also for correcting an image.  
       [0019] It is another object of the invention to effectively utilizing exposure parameters determined in metering process.  
       [0020] Another object of the invention is to shorten time required to correct an image.  
       [0021] These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0022]FIG. 1 is a perspective view showing the appearance of the front side of a digital camera according to a preferred embodiment of the invention;  
     [0023]FIG. 2 is a perspective view showing the appearance of the rear side of the digital camera;  
     [0024]FIG. 3 is a block diagram showing main components of the digital camera;  
     [0025]FIG. 4 is a diagram for explaining a metering;  
     [0026]FIG. 5 is a block diagram showing the functional configuration and the like of the digital camera;  
     [0027]FIGS. 6 and 7 are flowcharts showing the flow of an image capturing operation of the digital camera;  
     [0028]FIG. 8 is a flowchart showing another example of step S 25  in FIG. 7;  
     [0029]FIG. 9 is a diagram showing a state where an image is divided on the basis of the position of a metering area;  
     [0030]FIG. 10 is a flowchart showing the flow of correcting a divided area;  
     [0031]FIGS. 11 and 12 are diagrams for explaining a specific example of correction by the digital camera when multi-area metering is carried out;  
     [0032]FIG. 13 is a flowchart showing further another example of step S 25  in FIG. 7;  
     [0033]FIG. 14 is a system diagram showing an image processing apparatus and a digital camera according to another preferred embodiment of the invention;  
     [0034]FIG. 15 is a block diagram showing the internal configuration of a computer;  
     [0035]FIG. 16 is a diagram showing the structure of image data; and  
     [0036] FIGS.  17  to  19  are block diagrams showing various information and the functional configuration of the computer. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0037] 1. First Preferred Embodiment  
     [0038]FIG. 1 is a perspective view showing the appearance of the front side of a first digital still camera  1  according to a preferred embodiment of the invention. FIG. 2 is a perspective view showing the appearance of the rear side of the digital camera  1 .  
     [0039] As shown in FIG. 1, the digital camera  1  has a structure that a detachable lens unit  12  is attached to a camera body  10 . In the front upper part of the camera body  10 , a flash unit  101  is provided to emit flash light as necessary toward a subject. On the top face, a release button  102  for allowing the digital camera  1  to perform an image capturing operation and a simple display  103  for displaying the frame number at the time of image capturing, setting in various operation modes, and the like are provided.  
     [0040] The lens unit  12  has a configuration that a plurality of lens elements are held by a lens barrel. Optical system constructed by the plurality of lens elements lead light from the subject to a CCD provided as a solid-state image pickup device in the camera body  10 . Consequently, an image of the subject is formed on the CCD. The lens unit  12  also has therein a driving mechanism for moving lenses and an aperture.  
     [0041] As shown in FIG. 2, on the rear face of the camera body  10 , a display  111  for displaying a captured image, an operation menu, and the like and operation buttons  112  for performing an operation in accordance with information displayed on the display  111  are disposed. The operation buttons  112  include a center button  112   a , and an upper button  112   b , a lower button  112   c , a left button  112   d , and a right button  112   e  which are disposed on the upper, lower, left, and right sides of the center button  112   a , respectively.  
     [0042] An optical viewfinder  113  used by the user to find the subject is provided on an upper part of the rear face, and a slit-shaped card slot  114  to which a memory card as an external recording medium is inserted is provided on a side of the camera body  10 .  
     [0043] At the time of capturing an image, the operating mode of the digital camera  1  is switched to an image capturing mode, and images of the subject continuously captured by the CCD are displayed as live view. The image capturing range may be checked through the finder  113 . When the user presses the release button  102  to half stroke, preparation for image capturing such as focus lock is made. When the user presses the release button  102  to full stroke, the image capturing and recording operation is executed. In the image capturing mode, when the upper button  112   b  is pressed, the lens is moved to the telescopic side. When the lower button  112   c  is pressed, the lens is moved to the wide side.  
     [0044] At the time of playing back an image, the operating mode of the digital camera  1  is switched to a playback mode, and an image captured is displayed on the display  111 . By pressing the upper button  112   b  in the operation buttons  112 , recorded images are played back and displayed in forward order. By pressing the lower button  112   c , the recorded images are played back and displayed in the opposite order. In the playback mode, as necessary, a plurality of captured images are displayed as thumbnail images on the display  111 . An image is temporarily selected by using the upper, lower, left, and right buttons  112   b  to  112   e . By pressing the center button  112   a , the selected image is enlarged and displayed.  
     [0045]FIG. 3 is a block diagram showing the configuration of the digital camera  1 . As shown in FIG. 3, in the digital camera  1 , various components are electrically connected to a CPU  21 , so that the CPU  21  controls the whole operation of the digital camera  1 . In FIG. 3, components other than the major components connected to the CPU  21  are not shown.  
     [0046] An operation program  221  for the digital camera  1  is stored in a ROM  22  connected to the CPU  21 . The CPU  21  performs a computing and control process in accordance with the program  221 , thereby realizing the operation of the digital camera  1 .  
     [0047] On a photoreceiving surface of a CCD  23 , an image of the subject is formed via the optical system in the lens unit  12 , and an image signal for forming an image of the subject is outputted from the CCD  23 . The image signal from the CCD  23  is converted by an A/D converter  24  to a digital signal and the digital signal is stored in an image memory  25 .  
     [0048] A correcting section  26  corrects the hue, contrast, and the like of an image (to be accurate, an image signal, but will be referred to as an “image” as appropriate in the following description) recorded in the image memory  25 .  
     [0049] A metering section (photometering section)  27  measures the brightness of the subject. A measurement value (hereinbelow, called a “metering value”) as a metering result is used to calculate the exposure parameters such as exposure time and an F-number by the CPU  21 . At the time of capturing an image, lens driving and aperture in the lens unit  12 , and exposure time of the CCD  23  are controlled by the CPU  21  on the basis of the exposure parameters and a signal from an AF sensor (not shown).  
     [0050] A header or the like is properly added to an image held in the image memory  25  by the user and a resultant image is stored as image data  281  in a RAM  28 . Further, the image data  281  stored in the RAM  28  can be transferred to a memory card  9  via the card slot  114 . Consequently, the image data  281  can be read by a computer separately provided.  
     [0051] In the digital camera  1 , the metering type at the time of image capturing can be switched between the spot metering and the multi-area metering by using the operation buttons  112 . The spot metering in the digital camera  1  denotes a method of measuring the brightness in a central portion in the image capturing range. The multi-area metering denotes a method of measuring the brightness in a plurality of areas in the image capturing range.  
     [0052] The switch between the spot metering and the multi-area metering is performed by, first, displaying a menu on the display  111  by the operation of the operation buttons  112  and selecting one of a plurality of items indicative types of the metering. The operation buttons  112  also function as means for switching the metering type.  
     [0053]FIG. 4 is a diagram showing a state of spot metering and multi-area metering in the digital camera  1 . As shown in FIG. 4, a plurality of metering areas  71  are preset in the image capturing range (that is, in an image to be captured). In the case of the spot metering, the brightness in a center metering area  71   a  (hatched area) is measured by the metering section  27 . In the case of the multi-area metering, the brightness of all the metering areas  71  is measured by the metering section  27 . A metering value of each metering area  71  is obtained as an average value of brightness of pixels corresponding to the metering area  71 . That is, the CCD  23  and the metering section  27  for performing a computing process function as means for measuring the brightness.  
     [0054]FIG. 5 is a block diagram showing a functional configuration realized when the CPU  21  in the digital camera  1  performs a computing process in accordance with the program  221 . In FIG. 5, an exposure determining section  31  and a correction controlling section  32  have the function realized by the CPU  21  and the like. All or a part of the functions may be realized by a dedicated electric circuit in place of CPU  21 . Specifically, as shown in FIG. 3, (a part of) the correcting section  26  may be provided as a dedicated electric circuit separate from the CPU  21 . All or a part of the other functional components may be realized by a dedicated electric circuit. In FIG. 3, similarly, all or a part of the metering section  27  shown as a separate section from the CPU  21  may be realized by the CPU  21  and the like.  
     [0055]FIGS. 6 and 7 are a flowchart showing the flow of operations of capturing an image of the digital camera  1 . With reference to FIGS.  4  to  7 , the operations of the digital camera  1  will be described hereinbelow.  
     [0056] In the image capturing mode, live view display is performed in such a manner that an image captured by the CCD  23  is transferred to the display  111  and an image displayed on the display  11  is updated almost real time. Consequently, the user can capture the subject while watching the display  111 . The subject may be also captured via the optical viewfinder  113 .  
     [0057] After the subject and the image capturing range are determined, the user half-pushes the release button  102  (step S 11 ), thereby controlling the lens movement on the basis of the measurement value from the AF sensor, and automatic focus adjustment is carried out (step S 12 ). Further, the metering section  27  measures brightness by the metering preset by the operation buttons  112 , and the exposure determining section  31  determines the exposure parameters such as F-number and exposure time on the basis of the result of the metering (step S 13 ).  
     [0058] In the case where the multi-area metering is performed, by executing a predetermined algorithm on a plurality of metering values, a scene determining section  311  in the exposure determining section  31  performs scene determination of determining the relation between distribution of brightness in the image being captured and the type of the subject. Specifically, a check is made to determine whether the scene is an enlarged scene of a subject, a special scene such as night scene, an indoor scene, a backlight scene, or others. The exposure determining section  31  determines the exposure parameters on the basis of the result of the scene determination.  
     [0059] In the case of the multi-area metering, further, at least one of:  
     [0060] 1) metering values of the metering areas  71 ; and  
     [0061] 2) the scene determination result derived from the metering values, s stored as metering related information (steps S 14  and S 15 ). The item of the metering related information to be stored is appropriately determined according to a correcting process which will be described hereinlater.  
     [0062] After that, by full-pressing the release button  102  (step S 21 ), charge accumulation of the CCD  23 , that is, the exposing operation is executed, and an image of the subject is stored in the image memory  25  (step S 22 ). Subsequently, a correcting process determining section  321  in the correction controlling section  32  receives the information as to the metering type just used from the metering section  27  to confirm whether the metering type is the spot metering or the multi-area metering (step S 23 ). In the case of the spot metering, image correction adapted to the spot metering is made by the correcting section  26  (step S 24 ). In the case of the multi-area metering, another image correction is made by referring to the metering related information (step S 25 ). That is, in the digital camera  1 , the correcting process determining section  321  determines the correcting process according to the metering type and, the correcting section  26  corrects an image in accordance with the correcting process determined.  
     [0063] In the digital camera  1 , the brightness in the metering area  71  in the central area of the image is measured through the spot metering as shown in FIG. 4. Such metering is used when the user places importance on the central area such as a case where the main subject is positioned in the center of the image. In the correction adapted to the spot metering, therefore, image correction to optimize the hue and contrast in the metering area  71  a is made to reflect the intention of the user.  
     [0064] Whether skin colors exist in the metering area  71  a and its vicinity or not is also determined. When yes, image correction adapted to a human is made in the center area. Specifically, in the case where skin colors exist in the center area and its vicinity in the image at the time of spot metering, the scene determining section  323  in the correction controlling section  32  determines that the possibility that the image is an image of a human is high. The correcting section  26  makes image correction so as not to exceed a predetermined degree of contrast in accordance with the result of scene determination, thereby preventing a skin color from being undesirably corrected to a grained image.  
     [0065] When the correcting process determining section  321  confirms that the multi-area metering was conducted at the time of image capturing, the result of the scene determination made to determine the exposure parameters (hereinbelow, called “scene determination for exposure”) is directly used for the image correction. That is, when “backlight” is determined by the scene determination for exposure, image correction of making a dark area light and increasing the contrast, i.e., enhancing gradation steps, is made. When “night scene” is determined, image correction of increasing the contrast in the entire image or the like is made. It eliminates the need to restart the full process of the scene determination for the image correction. It is unnecessary to completely omit the full process of the scene determination at the time of image correction (hereinbelow, called “scene determination for image correction”). The scene determination for image correction may be simplified by using the result of the scene determination for exposure. In this case as well, time required for image correction is shortened. After completion of the image correction, the metering related information stored may be properly erased.  
     [0066] For the image correction in the case where the multi-area metering is made, the plurality of metering values used at the time of determining the exposure parameters may be used. FIG. 8 is a flowchart showing, as another example of step S 25 , the flow of image correction in the case where the result of the scene determination for exposure and the metering value as the metering result are used.  
     [0067] In the case of using the metering values, first, by a dividing section  322  in the correction controlling section  32 , as shown in FIG. 9, an image captured is divided into a plurality of divided areas  72  by using the position of the metering areas  71  as a reference position (step S 311 ). Each of respective images in the divided areas  72  is corrected by the correcting section  26  by using the metering values in accordance with the result of the scene determination for exposure (step S 312 ).  
     [0068]FIG. 10 is a flowchart showing the flow of processes for correcting each of the images in the divided areas  72  by using the metering values. In the correction of each image of the divided areas  72 , first, one divided area  72  to be corrected is determined (step S 41 ), and whether the divided area  72  is a divided area including the metering area  71  or not is checked (step S 42 ). In the case where the divided area  72  includes the metering area  71 , by using the metering value obtained from the metering area  71 , whether image correction is necessary or not and what kind of image correction is to be made is determined. When image correction is necessary, image correction is made (step S 43 ). When the divided area  72  does not include the metering area  71 , a computing process is performed by using the respective values of the pixels in the divided area  72  to determine whether image correction is necessary or not and, further, what kind of image correction is to be made is. After that, image correction is made as necessary (step S 44 ).  
     [0069] After completion of the process for correcting the one divided area  72 , whether an unprocessed divided area  72  exists or not is determined (step S 45 ). When one or more unprocessed divided areas  72  exists, any of the unprocessed divided areas  72  is determined as a new correction target and the image thereof is corrected (steps S 41  to S 44 ). When image correction on all of the divided areas  72  is completed, the image process is finished.  
     [0070] As described above with reference to FIG. 10, the process of determining various parameters for the image correction of the divided area  72  including the metering area  71  is performed such that the process of obtaining the brightness of the area from the pixel values is omitted and the metering value used at the time of determining the exposure parameters is used. The number of computing steps in a whole correcting process are therefore reduced, and reduction in time required to correct the whole image is attained.  
     [0071]FIGS. 11 and 12 are diagrams for explaining a specific example of the processes shown in FIGS.  6  to  8  and FIG. 10. FIG. 11 shows the positions of the metering areas  71  at the time of capturing an image in a backlight environment. At the time of calculating the exposure parameters, since the metering value (brightness) of the metering areas  71  corresponding to the human are small, the determination result of “backlight” is derived by the scene determining section  311  in the exposure determining section  31  shown in FIG. 5 (step S 13  in FIG. 6). The result of the scene determination for exposure and the metering value are stored as metering related information in the RAM  28  (step S 15 ).  
     [0072] The information that the multi-area metering has been conducted is supplied from the metering section  27  to the correction controlling section  32 . At the time of image correction, the correcting process determining section  321  switches the correcting process to the correcting process adapted to multi-area metering (step S 23  in FIG. 7). To make image correction utilizing the metering value, the dividing section  322  divides the image into a plurality of divided areas  72  on the basis of the positions of the metering areas  71  as shown in FIG. 12 (step S 311  in FIG. 8). The correcting section  26  determines whether image correction for backlight is necessary or not on each of the divided areas  72  by referring to the result of the scene determination for exposure. When it is determined that the image correction is necessary, image correction such as contrast enhancement or increase in brightness is made.  
     [0073] At the time of determining whether the correction for backlight is necessary or not by the correcting section  26 , the metering value is used for each divided area  72  including the metering area  71 . To be specific, when the metering value is small, it is determined that image correction for backlight is necessary. In each divided area  72  which does not include the metering area  71 , whether image correction for backlight is necessary or not is determined from the values of the pixels included in the divided area  72 . Finally, it is determined that the image of an area  731  surrounded by thick lines in FIG. 12 has to be corrected on the basis of the metering value. It is determined that the image of an area  732  surrounded by thick lines has to be corrected by performing a computing process on the pixel values. The divided areas  72  in the areas  731  and  732  are subjected to image correction (FIG. 10).  
     [0074] At the time of image correction as well, in the divided area  72  including the metering area  71 , parameters for image correction such as the degree of contrast enhancement and the degree of increase in brightness are calculated on the basis of the metering value. In the divided area  72  which does not include the metering area  71 , parameters for image correction are calculated from the values of pixels included in the divided area  72 .  
     [0075] As described above, by determining the divided areas  72  each as a unit of image correction on the basis of the positions of the metering areas  71  in the multi-area metering, the metering value may be also used for the determination whether each image of the divided areas  72  has to be corrected or not and for the image correction of each divided area  72 . Further, since the result of the scene determination for exposure is also used at the time of image correction, it is unnecessary to separately determine the scene for the correction. As a result, time required for the image correction can be reduced.  
     [0076] The processes shown in FIG. 8 are an example of using not only the result of the scene determination for exposure but also the metering value in the image correction. On the other hand, FIG. 13 is a flowchart showing the process of correction (step S 25  in FIG. 7) in the case of using only the metering value as metering related information in the image correction.  
     [0077] Also in the case where only the metering value is used for correction, first, the dividing section  322  divides the image into the plurality of divided areas  72  by using the positions of the metering areas  71  as a reference as shown in FIG. 9 (step S 321 ). Next, by using the metering value, the scene determining section  323  performs the scene determination for image correction (step S 322 ). In the scene determination for image correction, various parameters are calculated on the basis of the brightness and hue of each of the divided areas  72 , and the scene is determined in consideration of a difference between the parameters and those of another divided area  72 . At this time, in the divided area  72  including the metering area  71 , the metering value is used as it is as information of brightness. Consequently, the number of the computing steps in the scene determination for the image correction is reduced.  
     [0078] After that, in accordance with the result of the scene determination for image correction, as shown in FIG. 10, by using the metering value, each of the images of the divided areas  72  is corrected by the correcting section  26  (step S 323 ). That is, in the divided area  72  including the metering area  71 , determination of the necessity of the image correction and necessary correction are executed by using the metering value.  
     [0079] As described above, in the digital camera  1 , the information indicative of the metering type used in image capturing is supplied to the correction controlling section  32 . Which one of the correcting process adapted to the spot metering and the image correcting process adapted to the multi-area metering is used is determined by the correcting process determining section  321 . Therefore, it is sufficient for the user to select the metering type by using the operation buttons  112  to conduct proper image correction.  
     [0080] In the case where the spot metering is carried out, the image correction is made by using the values of pixels corresponding to the metering area  71  a where the brightness is measurement. Consequently, image correction in which the intention of the user is reflected is realized.  
     [0081] In the correction where the multi-area metering is carried out, the result of the scene determination for exposure at the time of determining the exposure parameters and/or the metering value are/is used. Thus, the time required for image correction can be shortened, and the prompt process is realized.  
     [0082] 2. Second Preferred Embodiment  
     [0083]FIG. 14 is a diagram showing a computer  40  and its peripheral devices functioning as an image processing apparatus according to a second preferred embodiment of the invention. The computer  40  performs the correction of an image, which is made in the digital camera  1  in the first preferred embodiment. As shown in FIG. 14, a keyboard  41   a  and a mouse  41   b  for receiving an manual operation of the user and a display  42  for displaying various visual information for the user are connected to the computer  40 . It can be also regarded that an image processing apparatus is constructed by those components.  
     [0084] Image data may be entered from a digital camera  1   a  via a memory card, a communication cable, and the like. The digital camera  1   a  has the configuration similar to that of an ordinary digital camera except that information of a metering type, a result of scene determination for exposure, a metering value, and the like used by the correction control section  32  shown in FIG. 5 can be outputted to the computer  40  via a memory card or the like.  
     [0085] In order make the computer  40  function as an image processing apparatus, a software program for correcting an image is installed in advance to the computer  40  via a recording medium  8  such as an optical disk, magnetic disk, magnetooptic disk, or memory card. A program may be installed via on-line computer communication through a network such as the Internet.  
     [0086]FIG. 15 is a block diagram showing the internal configuration of the computer  40  together with the peripheral devices. As shown in FIG. 15, the computer  40  has a configuration similar to that of an ordinary personal computer, in which a CPU  401  for performing various computing processes, a ROM  402  for storing a basic program, a RAM  403  for storing a software program for image correction or serving as a work area of a computing process, and the like are connected to a bus line. To the bus line, peripheral devices such as the display  42 , a fixed hard disk  404  for storing various software programs including the program  431  for image correction, a reading section  405  for reading a software program and the like from the recording medium  8 , a card slot  406  for transferring image data to/from the digital camera  1   a  via the memory card  9 , and the keyboard  41   a  and mouse  41   b  for receiving an entry from the user are connected via interfaces (I/F) as appropriate.  
     [0087] The program  431  for image correction is loaded via the reading section  405  (or a communication section separately provided in the case of loading the program  431  through network communication) to the hard disk  404  and is copied to the RAM  403 . When the CPU  401  performs the computing process in accordance with the program  431 , the computer  40  functions as an image correcting apparatus.  
     [0088]FIG. 16 is a diagram showing the structure of image data  91  captured by the digital camera  1   a . The image data  91  is comprised of a header  910  for storing various information regarding the captured image and an image signal  920  indicative of the body of the image data. The header  910  includes:  
     [0089] 1) information  911  indicative of the type of the metering process used at the time of capturing the image (hereinbelow, called “metering process information”);  
     [0090] 2) result  912  of scene determination for exposure (hereinbelow, called “scene determination result”) used at the time of determining the exposure parameters;  
     [0091] 3) a metering result  913  as a metering value; and  
     [0092] 4) metering area information  914  as information of the position of the metering area  71 , which may include information of size and shape the metering area  71 , shown as an example in FIG. 11.  
     [0093] As shown in FIG. 16, the metering related information, information of the metering and the like, which is erased after completion of image correction in the digital camera  1  according to the first preferred embodiment, is stored as well as an image signal in the digital camera  1   a  according to the second preferred embodiment. Only information necessary for the computer  40  to correct the image according to the kind of image correction may be properly included in the header  910 .  
     [0094] According to the format of an image file, elements of the information whose storage location is reserved are stored in the location, and other elements of the information whose storage location is not reserved are stored in the user area. For example, for file formats such as Exif (Exchangeable image file format) and DCF (Design rule for Camera File system) obtained by expanding the Exif, storage locations of the metering process information  911  are reserved. The scene determination result  912 , metering result  913 , and metering area information  914  are stored in the user area in the header  910 .  
     [0095] FIGS.  17  to  19  are block diagrams showing the functional configuration of the computer  40  in the case of processing the image data  91  having the data structure shown in FIG. 16 by the computer  40 . In the diagrams, a correcting process determining section  51 , a correcting section  52 , a dividing section  53 , and a scene determining section  54  correspond to the functional components realized by the CPU  401 , ROM  402 , RAM  403  and the like in FIG. 15. Processes realized by the functional components are those in steps S 23  to S 25  in FIG. 7.  
     [0096] The image data  91  transferred from the digital camera  1   a  is stored in the RAM  403 . In FIGS.  17  to  19 , information transferred between the various functional components and the RAM  403  is also properly shown.  
     [0097]FIG. 17 shows the functional configuration in the case where only the metering process information  911  and the scene determining result  912  are used to correct an image (to be accurate, the image signal  920 ) in the computer  40 . In FIG. 17, the correcting process determining section  51  obtains the metering process information  911 , checks that the metering type used at the time of image capturing is either spot metering or multi-area metering, and determines an image correcting process in accordance with the metering type (corresponding to step S 23 ).  
     [0098] In the case where the metering process information  911  indicates the spot metering, the above-described image correction for spot metering is made (corresponding to step S 24 ). In the case where the metering process information  911  indicates the multi-area metering, the correcting section  52  corrects an image by using the scene determination result  912  (corresponding to step  25 ).  
     [0099]FIG. 18 shows the functional configuration in the case where the computer  40  corrects an image by using the scene determination result  912 , metering result  913 , and metering area information  914  when the metering process information  911  indicates the multi-area metering, that is, when the processes shown in FIGS. 8 and 10 are performed by the computer  40 .  
     [0100] In FIG. 18, first, the correcting process determining section  51  obtains the metering process information  911  and selects an image correction adapted to multi-area metering (corresponding to step S 23 ). On the basis of the metering area information  914 , the dividing section  53  divides an image (step S 311 ). In the dividing section  53 , information indicative of the size of an image in the header  910  is also supplied. After that, the correcting section  52  executes the correction of each image of the divided areas on the basis of the scene determination result  912  and the metering result  913  (step S 312  in FIG. 10).  
     [0101]FIG. 19 shows the functional configuration in the case where the computer  40  corrects an image on the basis of the metering result  913  and metering area information  914  when the metering process information  911  indicates the multi-area metering, that is, when the processes shown in FIGS. 13 and 10 are performed by the computer  40 . In FIG. 19 as well, the correcting process determining section  51  obtains the metering process information  911  and selects an image correction adapted to multi-area metering (corresponding to step S 23 ). On the basis of the metering area information  914 , the dividing section  53  divides an image (step S 321 ). The scene determining section  54  performs scene determination for image correction on the basis of the metering result  913  (step S 322 ), and the correcting section  52  executes the correction of each image of the divided areas on the basis to the result of the scene determination for image correction and the metering result  913  (step S 323  in FIG. 10).  
     [0102] As described above, the image correcting process in the first preferred embodiment may be performed also by the computer  40 , thereby enabling image capturing in the digital camera to be promptly performed. By executing the above-described image correction by using the computer  40 , in a manner similar to the first preferred embodiment, proper correction according to the metering is realized. In the case where the multi-area metering is performed, the scene determination result  912  and the metering result  913  used for determining the exposure parameters are also used for image correction, so that the time required for image correction can be shortened.  
     [0103] 3. Modifications  
     [0104] In place of the metering using the CCD  23 , a plurality of dedicated metering devices provided in the digital camera  1  may be used for metering. In this case, the metering areas  71  are determined by using the correspondence of each metering device to each area in the image capturing range.  
     [0105] A metering type other than the spot metering and the multi-area metering may be also employed. For example, averaging metering in which an average of brightness of a whole image capturing range is calculated may be used. In the case of the averaging metering, an image correcting process for averaging metering is selected by the correcting process determining section.  
     [0106] In place of performing the spot metering only in the center metering area  71   a  in the image capturing range, the area for the spot metering can be changed according to the position of the main subject. In the case of a method of performing metering while weighting the metering value in a specific metering area  71  such as centerweighted metering, the image correction for spot metering can be used.  
     [0107] In place of using the result of the scene determination for image correction, which is led from the metering value in the multi-area metering, other information may be used as information led from the metering value, i.e., so-called AE determination information.  
     [0108] In the above description, in the case where the multi-area metering is performed and the metering value is used, an image is divided on the basis of the positions of the metering areas  71 . However, at the stage of step S 322  in FIG. 13, an image may not yet be divided. For example, it is also possible to calculate an average value of brightness in the center area of the divided area  72  which does not have the metering area  71  in FIG. 12 and perform scene determination for image correction by using the average value and the metering value.  
     [0109] A gap may not exist between neighboring metering areas  71 . In the case of performing metering by using the CCD  23 , the size and shape of the metering area  71  can be freely changed in a software manner. The metering area  71  and the divided area  72  may coincide with each other. In this case, at the time of image correction, the metering value can be more properly used.  
     [0110] In the image processing apparatus in the second preferred embodiment, all or a part of the function components shown in FIGS.  17  to  19  may be realized by a dedicated electric circuit(s).  
     [0111] The invention can be applied not only to the digital still camera in the preferred embodiments but also a digital movie camera.  
     [0112] While the invention has been shown and described in detail, the foregoing description in all aspects illustrative and not restrictive. It is therefore understood that numerous other modifications and variations can be devised without departing from the scope of the invention.