Imaging device

Abstract

This imaging device includes: an imaging means; and recording means for generating a main image and a plurality of sub-images from an image obtained by means of imaging by the imaging means, and recording a specific image from among the main image and the plurality of sub-images in a recording medium as one image file together with first supplementary information in which the specific image is referenced as an image for display and second supplementary information in which the specific image is referenced as an image for original holding.

Description

Imaging device

[0001] The present invention relates to an imaging device, a control method for an imaging device, and a program.

[0002] In recent years, information sharing via the Internet and SNS has become active, and it has become an era in which anyone can view and transmit information. Under such circumstances, since the technology for processing digital images has further evolved, it has become difficult for viewers of information to confirm the authenticity of the viewed content, and problems such as fake news have become more serious. In order to address such problems, there is an increasing demand for a mechanism to prove the authenticity (that no processing or forgery has been performed) of digital images.

[0003] Therefore, a authenticity proof function is known in which an image taken at the time of shooting is used as an original image, a part or the whole of an image file including the original image is hashed, and the hash value is encrypted using an individual encryption key. By attaching such a digital signature to an image, it is possible to prove that no processing or forgery has been performed on the hashed area within the image.

[0004] Japanese Patent Application Laid-Open No. 2008-54,21

[0005] On the other hand, in the MPF (Multi Picture Format) standard for storing a sub-image in the same file as the main image, in addition to being able to store a sub-image for displaying the main image, a type of original holding image for holding the original image is provided. However, since the original holding image is often the same as or a resized image of the main image, it is redundant when storing a sub-image for display as well.

[0006] An imaging device that includes imaging means and generates a main image and a plurality of sub-images from an image obtained by imaging with the imaging means, and records as one image file on a recording medium together with first attachment information that refers to a specific image among the plurality of sub-images as a display image and second attachment information that refers to the specific image as an original holding image.

[0007] According to the present invention, the redundancy of an image file can be reduced.

[0008] This is a schematic diagram of the imaging device. This is a schematic diagram of the imaging device. This is a diagram showing the configuration of the imaging device. This is a diagram showing an image file captured in authenticity verification mode. This is a diagram showing an image file captured in authenticity verification mode. This is a diagram showing an image file captured in authenticity verification mode. This is a flowchart for generating the image file at the time of capture. This is a diagram explaining the method of recording data at the time of capture. This is a diagram explaining the method of recording data at the time of capture. This is a flowchart for generating the image file during image processing.

[0009] The embodiments for carrying out the present invention will be described in detail below with reference to the attached drawings.

[0010] The embodiments described below are merely examples of means for realizing the present invention, and may be modified or changed as appropriate depending on the configuration of the apparatus to which the present invention is applied and various conditions. Furthermore, the embodiments can be combined as appropriate.

[0011] <Configuration of the Imaging Device> Preferred embodiments of the present invention will be described below with reference to the drawings.

[0012] Figures 1A and 1B show an external view of a digital camera 100 as an example of a device to which the present invention can be applied. Figure 1A is a front perspective view of the digital camera 100, and Figure 1B is a rear perspective view of the digital camera 100. In Figures 1A and 1B, the display unit 28 is a display unit located on the back of the camera that displays images and various information. The viewfinder-external display unit 43 is a display unit located on the top of the camera that displays various camera settings, including shutter speed and aperture. The shutter button 61 is an operation unit for issuing shooting instructions. The mode switching switch 60 is an operation unit for switching between various modes. The terminal cover 40 is a cover that protects connectors (not shown) such as connection cables that connect external devices to the digital camera 100. The main electronic dial 71 is a rotating operation member included in the operation unit 70, and by rotating this main electronic dial 71, settings such as shutter speed and aperture can be changed. The power switch 72 is an operation member that switches the power of the digital camera 100 ON and OFF. The sub-electronic dial 73 is included in the operation unit 70 and is a rotating operating member included in the operation unit 70, which can be used to move the selection frame and advance images. The directional pad 74 is included in the operation unit 70 and is a directional pad (four-way key) whose up, down, left, and right parts can be pressed. Operations can be performed according to the part of the directional pad 74 that is pressed. The SET button 75 is included in the operation unit 70 and is a push button, mainly used to confirm selection items. The LV button 76 is included in the operation unit 70 and is a button that switches the live view (hereinafter referred to as LV) ON and OFF in the menu button. In video recording mode, it is used to instruct the start and stop of video recording. The zoom button 77 is included in the operation unit 70 and is an operation button for turning the zoom mode ON and OFF and changing the magnification ratio in the live view display in shooting mode. In playback mode, it functions as a zoom button to enlarge the playback image and increase the magnification ratio. The minimizing button 78 is included in the control unit 70 and is used to reduce the magnification ratio of the enlarged playback image, thereby shrinking the displayed image. The playback button 79 is also included in the control unit 70 and is used to switch between shooting mode and playback mode.By pressing the playback button 79 during shooting mode, the camera switches to playback mode, and the latest image recorded on the recording medium 200 can be displayed on the display unit 28. The quick-return mirror 12 is raised and lowered by an actuator (not shown) instructed by the system control unit 50. The communication terminal 10 is a communication terminal for the digital camera 100 to communicate with the lens side (detachable). The eyepiece viewfinder 16 is a look-through type viewfinder for checking the focus and composition of the optical image of the subject obtained through the lens unit 150 by observing the focusing screen 13. The cover 202 is the cover of the slot that houses the recording medium 200. The grip part 90 is a holding part shaped to be easily gripped by the user with their right hand when holding the digital camera 100.

[0013] Figure 2 is a block diagram showing an example configuration of the digital camera 100 according to this embodiment. In Figure 2, the lens unit 150 is a lens unit equipped with an interchangeable photographic lens. The lens 103 is usually composed of multiple lenses, but here it is shown simply as a single lens. Communication terminal 6 is a communication terminal for the lens unit 150 to communicate with the digital camera 100, and communication terminal 10 is a communication terminal for the digital camera 100 to communicate with the lens unit 150. The lens unit 150 communicates with the system control unit 50 via these communication terminals 6 and 10, and the internal lens system control circuit 4 controls the aperture 1 via the aperture drive circuit 2, and focuses by displacing the position of the lens 103 via the AF drive circuit 3.

[0014] The AE sensor 17 measures the brightness of the subject through the lens unit 150.

[0015] The focus detection unit 11 outputs defocus amount information to the system control unit 50. Based on this, the system control unit 50 controls the lens unit 150 and performs phase-detection autofocus.

[0016] The quick-return mirror 12 (hereinafter referred to as mirror 12) is raised and lowered by an actuator (not shown) at the command of the system control unit 50 during exposure, live view shooting, and video recording. Mirror 12 is a mirror that switches the light beam incident from the lens 103 between the viewfinder 16 side and the image sensor 22 side. Normally, mirror 12 is positioned to reflect the light beam to guide it towards the viewfinder 16, but when shooting is performed or live view is displayed, it flips up to guide the light beam towards the image sensor 22 and moves out of the way of the light beam (mirror up). In addition, the central part of mirror 12 is a half-mirror that allows some light to pass through, and transmits a portion of the light beam so that it enters the focus detection unit 11 for focus detection.

[0017] The photographer can observe the focusing screen 13 through the pentaprism 14 and viewfinder 16, thereby confirming the focus and composition of the optical image of the subject obtained through the lens unit 150.

[0018] The shutter 101 is a focal-plane shutter that allows the exposure time of the imaging unit 22 to be freely controlled by the system control unit 50.

[0019] The imaging unit 22 is an image sensor composed of a CCD or CMOS element, which converts optical images into electrical signals. The A / D converter 23 converts analog signals into digital signals. The A / D converter 23 is used to convert analog signals output from the imaging unit 22 into digital signals.

[0020] The image processing unit 24 performs resizing and color conversion processing, such as predetermined pixel interpolation and reduction, on the data from the A / D converter 23 or the data from the memory control unit 15. The image processing unit 24 also performs predetermined calculations using the captured image data. Based on the calculation results obtained by the image processing unit 24, the system control unit 50 performs exposure control and distance measurement control. This enables TTL (through-the-lens) AF (autofocus), AE (automatic exposure), and EF (flash pre-flash) processing. The image processing unit 24 further performs predetermined calculations using the captured image data and performs TTL (auto white balance) processing based on the calculation results obtained.

[0021] The output data from the A / D converter 23 is written to the memory 32 via the image processing unit 24 and the memory control unit 15, or directly via the memory control unit 15. The memory 32 stores image data obtained by the imaging unit 22 and converted into digital data by the A / D converter 23, as well as image data for display on the display unit 28. The memory 32 has sufficient storage capacity to store a predetermined number of still images, a predetermined amount of video footage, and audio.

[0022] Furthermore, memory 32 also serves as memory for image display (video memory). The D / A converter 19 converts the image display data stored in memory 32 into an analog signal and supplies it to the display unit 28. In this way, the display image data written to memory 32 is displayed by the display unit 28 via the D / A converter 19. The display unit 28 displays on a display device such as an LCD according to the analog signal from the D / A converter 19. The digital signal, which has been A / D converted once by the A / D converter 23 and stored in memory 32, is converted to analog by the D / A converter 19 and sequentially transferred to the display unit 28 for display. This allows it to function as an electronic viewfinder and perform through-image display (live view display (LV display)). Hereinafter, the image displayed in live view will be referred to as an LV image.

[0023] The LCD display unit 41 in the viewfinder displays, via the viewfinder display drive circuit 42, a frame (AF frame) indicating the focus point where autofocus is currently being performed, and icons indicating the camera's settings, etc.

[0024] The external viewfinder display unit 43 displays various camera settings, including shutter speed and aperture, via the external viewfinder display unit drive circuit 44.

[0025] The non-volatile memory 56 is an electrically erasable and recordable memory, such as an EEPROM. The non-volatile memory 56 stores constants for the operation of the system control unit 50, programs, etc. The program referred to here is a program for executing various flowcharts described later in this embodiment.

[0026] The system control unit 50 is a control unit consisting of at least one processor and / or at least one circuit, and controls the entire digital camera 100. It realizes each of the processes of this embodiment, which will be described later, by executing the program recorded in the non-volatile memory 56. For example, RAM is used in the system memory 52, and constants, variables for the operation of the system control unit 50, the program read from the non-volatile memory 56, etc. are stored there. The system control unit 50 also performs display control by controlling the memory 32, the D / A converter 19, the display unit 28, etc.

[0027] The system timer 53 is a timekeeping unit that measures the time used for various controls and the time of the built-in clock.

[0028] The mode switch 60, first shutter switch 62, second shutter switch 64, and operation unit 70 are operating means for inputting various operation instructions to the system control unit 50. The mode switch 60 switches the operating mode of the system control unit 50 to one of the following: still image recording mode, video recording mode, playback mode, etc. Modes included in the still image recording mode include auto shooting mode, auto scene detection mode, manual mode, aperture priority mode (Av mode), shutter speed priority mode (Tv mode), and program AE mode. There are also various scene modes and custom modes that provide shooting settings for different shooting scenes. The user can switch directly to any of these modes using the mode switch 60. Alternatively, the user can switch to a list screen of shooting modes using the mode switch 60, select one of the displayed modes, and then switch using other operating members. Similarly, the video recording mode may also include multiple modes.

[0029] The first shutter switch 62 turns ON during the operation of the shutter button 61 on the digital camera 100, specifically when it is half-pressed (instructing to prepare for shooting), and generates the first shutter switch signal SW1. The first shutter switch signal SW1 initiates operations such as AF (autofocus), AE (automatic exposure), AWB (auto white balance), and EF (flash pre-flash).

[0030] The second shutter switch 64 turns ON when the shutter button 61 is fully pressed (shooting instruction), generating the second shutter switch signal SW2. The system control unit 50 starts a series of shooting processes, from reading the signal from the imaging unit 22 to writing the image data to the recording medium 200, in response to the second shutter switch signal SW2.

[0031] Each operating element of the control unit 70 is assigned a function as appropriate for each situation by selecting various function icons displayed on the display unit 28, and acts as various function buttons. Examples of function buttons include an exit button, a back button, an image advance button, a jump button, a filter button, and an attribute change button. For example, when the menu button is pressed, various configurable menu screens are displayed on the display unit 28. Users can intuitively make various settings using the menu screen displayed on the display unit 28 and the four directional buttons (up, down, left, and right) and the SET button.

[0032] The operation unit 70 consists of various operating components that act as an input unit for receiving operations from the user. The operation unit 70 includes push buttons, rotary dials, touch sensors, etc., and includes at least the following operating components: shutter button 61, main electronic dial 71, power switch 72, sub electronic dial 73, directional pad 74, SET button 75, LV button 76, zoom in button 77, zoom out button 78, and playback button 79.

[0033] The power control unit 80 consists of a battery detection circuit, a DC-DC converter, a switch circuit for switching which blocks are energized, and the like, and detects whether a battery is installed, the type of battery, and the remaining battery level. The power control unit 80 also controls the DC-DC converter based on the detection results and instructions from the system control unit 50, and supplies the necessary voltage to each part, including the recording medium 200, for the required period of time. The power supply unit 30 consists of primary batteries such as alkaline batteries and lithium batteries, secondary batteries such as NiCd batteries, NiMH batteries, and lithium-ion batteries, an AC adapter, and the like.

[0034] The recording medium I / F 18 is an interface to a recording medium 200, such as a memory card or hard disk. The recording medium 200 is a recording medium such as a memory card for recording captured images, and is composed of semiconductor memory, magnetic disks, etc.

[0035] The communication unit 54 is connected wirelessly or via a wired cable and transmits and receives video and audio signals. The communication unit 54 can also connect to a wireless LAN (Local Area Network) or the Internet. Furthermore, the communication unit 54 can communicate with external devices using Bluetooth® or Bluetooth Low Energy. The communication unit 54 can transmit images (including LV images) captured by the imaging unit 22 and images recorded on the recording medium 200, and can also receive images and other various information from external devices.

[0036] The attitude detection unit 55 detects the orientation of the digital camera 100 relative to the direction of gravity. Based on the orientation detected by the attitude detection unit 55, it is possible to determine whether the image captured by the imaging unit 22 was taken with the digital camera 100 held horizontally or vertically. The system control unit 50 can add orientation information corresponding to the orientation detected by the attitude detection unit 55 to the image file of the image captured by the imaging unit 22, or rotate the image before recording. An acceleration sensor or gyro sensor can be used as the attitude detection unit 55. It is also possible to detect the movement of the digital camera 100 (pan, tilt, lift, whether it is stationary or not, etc.) using the acceleration sensor or gyro sensor in the attitude detection unit 55.

[0037] Figures 3A to 3C illustrate the image generation process and the mechanism for verifying authenticity when using the authenticity verification function in the shooting mode (authenticity verification shooting mode).

[0038] Figure 3A illustrates the data structure of an image file captured in normal shooting mode. Image file 301 represents the entire captured image file. Image file 301 conforms to the Exif standard and the format specified by the MPF (Multi-Picture Format) standard for storing secondary images in the same file as the main image. Image file 301 includes main image supplementary information 302, main image data 303, MPF supplementary information 304, and MPF display image data 305. Main image supplementary information 302 is an area that stores information about the main image at the time of shooting (parameters such as the date and time of shooting and settings at the time of shooting). Main image data 303 is an area where the captured main image data is stored. MPF supplementary information 304 is an area that stores data such as the number of secondary images recorded, the type of image, and the offset to the image data, which are stored in accordance with MPF. MPF display image data 305 is one of the secondary images stored in an MPF-compliant format and is image data stored for monitor display purposes.

[0039] On the other hand, Figure 3B illustrates the structure of image data captured in authenticity verification mode. Image file 306 represents the entire image file saved when captured in authenticity verification mode. Image file 306 includes main image supplementary information 302, main image data 303, MPF supplementary information 304, MPF display image data 305, MPF original retention image data 308, and authenticity verification data 307. Authenticity verification data 307 is information for verifying the authenticity of image file 301 and is used when verifying the origin and history of image file 301. MPF original retention image data 308 is one of the sub-images stored in an MPF-compliant format and is image data for retaining an image that represents the actual scene at the time of capture.

[0040] The authenticity verification data 307 is generated in accordance with a prescribed technical standard (for example, C2PA (Coalition for Content Protection and Authenticity)) and has a prescribed structure.

[0041] Figure 3C illustrates the data structure of the authenticity verification data 307. The authenticity verification data 307 includes provenance information (Assertion) 309 and a hash value 312 or digital signature 313 to guarantee the authenticity verification data 307. The provenance information 309 includes provenance metadata 310, which stores provenance identification information (Manifest ID) to uniquely identify the provenance and editing history showing the editing content of the image file 301, and a thumbnail image 311 corresponding to the main image data 303. This thumbnail image 311 may be a copy of the main image data 303 or it may be a resized version.

[0042] The hash value 312 stores the hash value obtained by performing a hash function on the main image supplementary information 302, main image data 303, MPF supplementary information 304, MPF display image data 305, and provenance information 309. The digital signature 313 includes a signature value generated by encrypting the hash value 312 using a pre-prepared private key. The public key that forms the pair of the private key used here is also stored together with the digital signature 313. These provenance information 309, hash value 312, and digital signature 313 are stored in the authenticity verification data 307. Then, by inserting the generated authenticity verification data 307 into a predetermined position in the image file 301, an image file 306 (Figure 3C) taken in authenticity verification shooting mode is generated. To verify whether this image has been tampered with, the following procedure is followed. The hash value obtained by decrypting the digital signature 313 with the public key is compared with the hash value obtained by executing a hash function on the main image supplementary information 302, main image data 303, MPF supplementary information 304, MPF display image data 305, and provenance information 309. If they match, the verification is deemed successful. If they do not match, it means that one of the data areas input to the hash function has been modified since the time the hash value was obtained, indicating the possibility of data tampering.

[0043] As described above, with reference to FIGS. 3A to 3C, in the authenticity verification mode, MPF original holding image data and authenticity verification data are created for an image file, embedded in the image file, and the mechanism until verification is explained. Further, the MPF original holding image data 308 stores a copy of the main image, which is the image at the time of first being saved as an image file after shooting, or a resized image. Furthermore, the MPF display image data 305 also stores a copy of the main image or a resized image according to its role. However, if this is done, the two images saved as sub-images will be the same. If such a file is used without being edited from the original or remains saved, the same image will be doubly recorded as the display image and the original holding image, which is redundant. In addition, not only does the file size increase, but when shooting using the authenticity verification function, the data size for hashing increases, so it takes time to calculate the hash value. Therefore, it will also have a great impact on the shooting performance.

[0044] Therefore, with reference to FIGS. 4 to 6, a method for solving this problem by referring to the same sub-image area for the MPF display image data and the MPF original holding image data will be described.

[0045] FIG. 4 is a flowchart at the time of shooting in an imaging device equipped with an authenticity verification mode. Here, in FIGS. 3A to 3C, for simplicity of explanation, the MPF display image is described in one case, but in the MPF standard, it is assumed that the MPF display image has a plurality of images for each specified resolution in one image file. FIG. 4 illustrates a flowchart in the case where images of two resolutions, Full HD and 4K, are stored in the MPF display image. The resolution of the original holding image is 4K. Each step is realized by the system control unit 50 expanding and executing a program stored in the non-volatile memory 56 in the memory 32. The shooting process in FIG. 4 is executed when the system control unit 50 receives a shooting start operation such as the photographer pressing the shutter button 61 of the imaging device 100.

[0046] In S401, the system control unit 50 drives the shutter to control the exposure time. In S402, the system control unit 50 performs imaging processing to convert the light from the subject received by the imaging unit 22 into an electrical signal. In S403, the system control unit 50 causes the A / D converter 23 to convert the electrical signal (analog signal) output from the imaging unit 22 into a digital signal. In S404, the system control unit 50 generates imaging data by performing development processing such as color and tone correction and optical correction on the data indicated by the digital signal generated in S403. Then, the system control unit 50 writes the generated imaging data into the memory 32. In S405, the system control unit 50 compresses the captured data developed in the memory 32 into a JPEG format or the like to create the main image data 501 in FIG. 5A. In S406, the system control unit 50 generates the attached information 504 of the main image and writes it into the memory 32.

[0047] Next, in S407, the system control unit 50 reads the set value regarding the shooting mode from the non-volatile memory 56 and determines whether the shooting mode is set to either the normal mode or the authenticity certification shooting mode. It is assumed that the photographer has selected either the normal mode or the authenticity certification shooting mode by menu operation or the like before the system control unit 50 receives a shooting start operation such as pressing the shutter button 61 of the imaging device 100.

[0048] If the system control unit 50 determines in S407 that the shooting mode is set to the normal mode, the process proceeds to S408. On the other hand, if the system control unit 50 determines that the shooting mode is set to the authenticity certification shooting mode, the process proceeds to S413.

[0049] First, the processing in the normal shooting mode will be described.

[0050] In S408, the system control unit 50 generates multiple sub-images from the main image. For example, it resizes the captured data expanded in memory 32 to a predetermined resolution (FullHD), then compresses it to JPEG format or the like to create an MPF ​​image (FullHD) 502. In S409, the system control unit 50 resizes the captured data expanded in memory 32 to a predetermined resolution (4K), then compresses it to JPEG format or the like to create an MPF ​​image (4K) 503.

[0051] In S410, the system control unit 50 generates MPF supplementary information 1 (505). The MPF supplementary information 1 (505) stores a type 506 indicating that the target image is a display image with Full HD resolution. Furthermore, it stores the data position of the specific sub-image (an offset value 507 from a predetermined position defined in the MPF standard to the beginning of the MPF image (Full HD) 502).

[0052] In S411, the system control unit 50 generates MPF supplementary information 2 (508). The MPF supplementary information 2 (508) stores a type 509 indicating that the target image is a display image with 4K resolution. Furthermore, it stores the data position of the specific sub-image (an offset value 510 from a predetermined position defined in the MPF standard to the beginning of the MPF image (4K) 503).

[0053] In S412, the system control unit 50 combines the main image accessory information 504, the MPF accessory information 511, the main image data 501, the MPF image (FullHD) 502, and the MPF image (4K) 503 to create a single recorded image file, which is then recorded on the recording medium 200. Here, the main image accessory information 504 is the main image accessory information 504 created in S409. The MPF accessory information 511 is the MPF accessory information 511 created in S410 to S411. The main image data 501 is the main image data 501 created in S406. The MPF image (FullHD) 502 is the MPF image (FullHD) 502 created in S407. The MPF image (4K) 503 is the MPF image (4K) 503 created in S408.

[0054] Then the process is finished. The above describes the process when the operating mode of the digital camera 100 is the normal shooting mode, not the authenticity verification shooting mode.

[0055] On the other hand, the following sections will explain the processing flow during authenticity verification shooting mode and the method for generating the recorded image file 512 using S413 to S419 and Figure 5B.

[0056] If the system control unit 50 determines in S405 that the authenticity verification shooting mode is set, in S413 the system control unit 50 resizes the shooting data expanded in memory 32 to a predetermined resolution (FullHD). Then, it compresses it to JPEG format or the like to create an MPF ​​image (FullHD) 513.

[0057] In S414, the system control unit 50 copies or resizes the captured data expanded in the memory 32 to a predetermined resolution, then compresses it into a format such as JPEG to create an MPF ​​image (4K) 514.

[0058] In this embodiment, the explanation assumes that the resolution of the original image to be retained is 4K.

[0059] Here, we consider the case where the main image is processed after it has been recorded and saved. In this case, the display image is an image used by the user to understand the content of the main image, so the display image needs to undergo the same image processing as the main image. On the other hand, the original retention image shows the content of the unedited image, so it must not be processed in any way. Therefore, in S414, an overwrite prevention enabled flag 516 is added to the MPF image (4K) 514 referenced as the original retention image to prevent it from being processed later.

[0060] Similarly, in S413, the MPF image (FullHD) 513 is referenced as a display image, and therefore its content needs to be changed through editing. For this reason, overwriting is permitted by assigning the overwrite prohibition disable flag 515 to the MPF image (FullHD) 513 (or by not assigning the overwrite prohibition enable flag).

[0061] In S416, the system control unit 50 generates MPF supplementary information 1 (517). The MPF supplementary information 1 (517) stores a type 518 indicating that the target image is a display image with Full HD resolution. Furthermore, it stores the data position of the specific sub-image (an offset value 519 from a predetermined position defined in the MPF standard to the beginning of the MPF image (Full HD) 513).

[0062] In S417, the system control unit 50 generates MPF supplementary information 2 (520). The MPF supplementary information 2 (520) stores a type 521 indicating that the target image is a display image with 4K resolution. Furthermore, it stores the data position of the specific sub-image (an offset value 522 from a predetermined position defined in the MPF standard to the beginning of the MPF image (4K) 514).

[0063] In S418, the system control unit 50 generates MPF supplementary information 3 (523). The MPF supplementary information 3 (523) stores a type 524 indicating that the target image is an original retention image with 4K resolution. Furthermore, it stores the data position of the specific target sub-image (an offset value 525 from a predetermined position defined in the MPF standard to the beginning of the MPF image (4K) 514).

[0064] In this way, a specific sub-image, the MPF image (4K) 514, is referenced as a 4K resolution display image by the supplementary information recorded in S417, and is also referenced as an original retention image by the supplementary information recorded in S418. In other words, since there is no need to separately store a 4K resolution display image and an original retention image, redundancy can be reduced.

[0065] In S419, the system control unit 50 generates authenticity verification data 526. First, it generates hash values ​​by executing a hash function on the main image supplementary information 526, MPF supplementary information 527, main image data 528, MPF image (FullHD) 513, MPF image (4K) 514, and provenance information. Next, it encrypts the hash values ​​using a pre-prepared secret key to create a digital signature. Then, it stores the provenance information, hash values, and digital signature together as authenticity verification data 526. Finally, in S412, the system control unit 50 creates a single recorded image file (512) from the main image supplementary information 512, MPF supplementary information 527, authenticity verification data 526, main image data 528, MPF image (FullHD) 513, and MPF image (4K) 514. The created recorded image file (512) is recorded on the recording medium 200. Then, the processing for the time of shooting is completed.

[0066] Next, Figure 6 illustrates a flowchart for performing image processing on a recorded image file 512. This flowchart is initiated, for example, when the user is viewing an image list in playback mode and inputs an instruction to perform a predetermined editing process on a specified image.

[0067] In S601, the system control unit 50 performs a predetermined image processing operation specified by the user on the main image data 528.

[0068] In S602, the system control unit 50 acquires MPF accessory information 1 (517), which is the first MPF accessory information to be recorded in MPF ​​accessory information 527. In S603, the system control unit 50 determines whether the type stored in the acquired MPF accessory information is an original retention image. If the system control unit 50 determines that the type is an original retention image, the process proceeds to S611. On the other hand, if the system control unit 50 determines that the type is not an original retention image, the process proceeds to S605.

[0069] In S605, the system control unit 50 determines the resolution of the target MPF image based on its type and resizes the image processed in S601 to a predetermined size. In S606, the system control unit 50 refers to the target MPF image from the offset value in the MPF attached information and determines whether the overwrite prohibition flag is enabled or disabled.

[0070] If the system control unit 50 determines that the overwrite prohibition flag is invalid (the overwrite prohibition invalid flag is on), the process proceeds to S607. On the other hand, if the system control unit 50 determines that the overwrite prohibition flag is valid (the overwrite prohibition valid flag is on), the process proceeds to S609.

[0071] In S607, the system control unit 50 overwrites and updates the target MPF image with the image resized in S605. In S608, the system control unit 50 updates the offset value in the MPF appended information to refer to the overwritten image.

[0072] In S609, the system control unit 50 adds the image resized in S605 as a new MPF image (processed sub-image). In S610, the system control unit 50 updates the offset value in the target MPF accessory information to the offset value to the beginning of the new MPF image added in S609, thereby changing the reference destination of the target MPF accessory information to the newly added MPF image.

[0073] In S611, the system control unit 50 determines whether the MPF attachment information acquired in S602 to S604 is the last MPF attachment information. If the system control unit 50 determines that it is the last MPF attachment information, the process proceeds to S612. If the system control unit 50 determines that it is not the last MPF attachment information, the process proceeds to S604.

[0074] In S604, the system control unit 50 acquires the following MPF-related information and returns to processing in S603.

[0075] In S612, the system control unit 50 reflects the updates to the processed main image, MPF image, and MPF associated information in the recorded image file 512, records the recorded image file on the recording medium 200, and ends the image processing.

[0076] The above is a description of the flowchart for image processing.

[0077] For example, in the case of the recorded image file 512 generated in S412 after going through S413 to S419 in Figure 4, the first MPF accessory information 1 (517) is acquired in S602, and since its type is for display (FullHD), the result in S603 is No. Also, since the overwrite prohibition invalid flag 515 is attached to the MPF image 513 at the address indicated by the MPF accessory information 1 (517), the result in S606 is No, and in S607 the MPF image 513 is overwritten and updated with an MPF ​​image that has the same content as the edited main image but a different size.

[0078] Next, in S604, which is executed via S611, MPF accessory information 2 (520) is acquired, and since its type is for display (4K), the result in S603 is No. Also, since the overwrite prohibition enabled flag is set for the MPF image 514 at the address indicated by MPF accessory information 2 (520), the result in S606 is No. Then, in S609, while the MPF image 514 remains unchanged, an MPF ​​image with the same content as the edited main image but a different size is added.

[0079] As described above, even if an MPF ​​image is treated as a display image, the MPF image referenced as the original image is not overwritten.

[0080] In this embodiment, the generation of data for authenticity verification and the recording of the original image for preservation were performed in conjunction with the on / off switching of the authenticity verification shooting mode, but this is not limited to this. For example, separate settings may be provided for turning on / off the generation of data for authenticity verification and for turning on / off the recording of the original image for preservation.

[0081] (Other Embodiments) The present invention can also be realized by supplying a program that implements one or more of the functions of the above embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more functions.

[0082] The present invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are attached to make the scope of the invention public.

[0083] This application claims priority based on Japanese Patent Application No. 2025-025295, filed on 19 February 2025, and all of its contents are incorporated herein by reference.

Claims

1. An imaging device comprising: an imaging means; a recording means that generates a main image and a plurality of sub-images from an image captured by the imaging means, and records a first auxiliary information that references a specific image among the plurality of sub-images as a display image, together with a second auxiliary information that references the specific image as an original retention image, as a single image file on a recording medium.

2. The imaging apparatus according to claim 1, characterized in that the specific image is a secondary image generated by copying or resizing the main image.

3. The imaging apparatus according to claim 1, characterized in that the specific image referenced as the original retention image is provided with information to prevent overwriting based on the attached information.

4. The imaging apparatus according to claim 1, further comprising control means for controlling an authenticity verification function that records history information indicating the generation process of the main image in the image file.

5. The imaging device according to claim 4, characterized in that, when the authenticity verification function is enabled and an image is obtained by imaging the imaging means, the recording means records the image file together with first ancillary information that references a specific image among the plurality of sub-images as a display image and second ancillary information that references the specific image as an original retention image, and when the authenticity verification function is disabled and an image is obtained by imaging the imaging means, the recording means records the image file together with first ancillary information that references a specific image among the plurality of sub-images as a display image, and does not record second ancillary information that references the specific image as an original retention image.

6. The imaging device according to claim 1, further comprising processing means for processing the main image of the image file, wherein, when the main image is processed while a particular image among the plurality of sub-images is not referenced as an original retention image by the second accompanying information, the particular image is processed to correspond to the processing of the main image, and when the main image is processed while a particular image among the plurality of sub-images is referenced as an original retention image by the second accompanying information, a processed sub-image which is a sub-image that has been processed to correspond to the processing of the main image is added, and the reference destination of the first accompanying information is changed to the processed sub-image.

7. A control method for an imaging device having an imaging means, comprising: a step of generating a main image and a plurality of sub-images from an image captured by the imaging means; and a recording step of recording the main image and the plurality of sub-images, together with first auxiliary information that references a specific image among the plurality of sub-images as a display image and second auxiliary information that references the specific image as an original retention image, as a single image file on a recording medium.

8. A computer-readable program for causing a computer to function as one of the means of the imaging apparatus described in any one of claims 1 to 4.

Images