Image processing device, imaging device, control method, and program

Abstract

This technology provides the ability to associate appropriate authenticity assurance information with synthesized images. [Solution] The present invention provides an image processing apparatus comprising association means for associating first authenticity assurance information, which includes information for guaranteeing the authenticity of a first image, with the first authenticity assurance information, which is configured to identify whether the first image is a composite image generated by combining multiple captured images corresponding to multiple exposures, or a non-composite image captured in a single exposure.

Description

Technical Field

[0001] The present invention relates to an image processing apparatus, an imaging apparatus, a control method, and a program.

Background Art

[0002] Conventionally, in order to ensure that an image captured by a digital camera has not been tampered with, a digital camera having a function of adding authentic guarantee information as verification data has been proposed.

[0003] For example, Patent Document 1 discloses a technique of embedding information (hash and signature value) for prohibiting tampering in an image file when shooting is performed in an image tampering prohibition mode.

[0004] In recent years, a technical standardization organization called C2PA has been established for the purpose of developing technical specifications that can guarantee the origin and reliability of content, enabling publishers, creators, and consumers to track the origin of media. The need for authentic guarantee has been attracting renewed attention. In the C2PA standard, a Manifest can be saved in an image generated at the time of shooting or editing as C2PA data. The Manifest can store an Actor (the name of the camera or software that generated the image), a hash value, a claim signature (digital signature), a thumbnail image, etc.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Some recent smartphones and other imaging devices have a function that captures multiple images, combines them according to some algorithm to generate a composite image, and records the composite image as a single photograph. Examples of such functions include HDR multi-shot, panoramic shooting, and multiple exposure shooting.

[0007] While such composite images are not necessarily tampered with, they may contain scenes that would be impossible to capture in a single exposure. Therefore, it is not appropriate to add (associate) authenticity assurance information to composite images according to conventional techniques.

[0008] This invention has been made in view of these circumstances, and aims to provide a technology that enables the association of appropriate authenticity assurance information with a composite image. [Means for solving the problem]

[0009] To solve the above problems, the present invention provides an association means for associating first authenticity assurance information, which includes information for guaranteeing the authenticity of the first image, with the first image. The first authenticity assurance information is configured to identify whether the first image is a composite image generated by combining multiple captured images corresponding to multiple exposures, or a non-composite image captured in a single exposure. The present invention provides an image processing apparatus characterized by the following features. [Effects of the Invention]

[0010] According to the present invention, it becomes possible to associate appropriate authenticity assurance information with a synthesized image.

[0011] Further features and advantages of the present invention will become clearer from the accompanying drawings and the description of the embodiments for carrying out the invention below. [Brief explanation of the drawing]

[0012] [Figure 1] A block diagram showing an example configuration of digital camera 100. [Figure 2A] A diagram showing an example of the structure of a composite image file. [Figure 2B] A diagram showing other examples of the configuration of a composite image file. [Figure 2C] A diagram showing an example of the structure of a non-composite image file. [Figure 3] A flowchart for the process of adding authenticity assurance information to an image. [Modes for carrying out the invention]

[0013] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims. While the embodiments describe multiple features, not all of these features are essential to the invention, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0014] [First Embodiment] Figure 1 is a block diagram showing an example configuration of a digital camera 100. The digital camera 100 is an example of an imaging device equipped with an image processing device. The imaging device may be, for example, a smartphone. Furthermore, a personal computer (PC) without a camera can perform the role of the image processing device in this embodiment.

[0015] The barrier 10 is a protective member that covers the imaging unit of the digital camera 100, including the photographic lens 11, to prevent dirt and damage to the imaging unit, and its operation is controlled by the barrier control unit 43. The photographic lens 11 forms an optical image on the imaging surface of the image sensor 13. The shutter 12 has an aperture function. The image sensor 13 is composed of, for example, a CCD or CMOS sensor, and converts the optical image formed on the imaging surface by the photographic lens 11 via the shutter 12 into an electrical signal.

[0016] The A / D converter 15 converts the analog image signal output from the imaging device 13 into a digital image signal. The digital image signal converted by the A / D converter 15 is written into the memory 25 as so-called RAW image data. At the same time, development parameters corresponding to each RAW image data are generated based on the information at the time of shooting and written into the memory 25. The development parameters are composed of various parameters used in image processing for recording images in the JPEG format, etc., such as exposure settings, white balance, color space, contrast, etc.

[0017] The timing generator 14 is controlled by the memory control unit 22 and the system control unit 50, and supplies clock signals and control signals to the imaging device 13, the A / D converter 15, and the D / A converter 21.

[0018] The image processing unit 20 performs various image processes such as predetermined pixel interpolation processing, color conversion processing, correction processing, resizing processing, and image synthesis processing on the data from the A / D converter 15 or the data from the memory control unit 22. Also, the image processing unit 20 performs predetermined image processing and arithmetic processing using the image data obtained by imaging, and provides the obtained arithmetic result to the system control unit 50. The system control unit 50 controls the exposure control unit 40 and the focus control unit 41 based on the provided arithmetic result, thereby realizing autofocus (AF) processing, automatic exposure (AE) processing, and flash pre-emission (EF) processing.

[0019] Also, the image processing unit 20 performs predetermined arithmetic processing using the image data obtained by imaging, and also performs auto white balance (AWB) processing based on the obtained arithmetic result. Furthermore, the image processing unit 20 reads the image data stored in the memory 25 and performs compression processing or decompression processing by, for example, the JPEG format, the MPEG-4 AVC format, the High Efficiency Video Coding (HEVC) format, or a reversible compression format for uncompressed RAW data. Then, the image processing unit 20 writes the processed image data into the memory 25.

[0020] In addition, the image processing unit 20 performs predetermined arithmetic processing using the image data obtained by imaging, and performs editing processing of various image data. Specifically, it can perform trimming processing to adjust the display range and size of the image by making unnecessary parts around the image data invisible, and resize processing to change the size by enlarging or reducing the image data or display elements of the screen. Further, the image processing unit 20 can perform RAW development to create image data by applying image processing such as color conversion to data that has been compressed or decompressed by a reversible compression method or the like for non-compressed RAW data, and converting it into data in the JPEG format or HEVC format. Also, the image processing unit 20 can perform video extraction processing to extract a specified frame of a video format such as MPEG-4, convert it into data in the JPEG format, and save it.

[0021] In addition, the image processing unit 20 performs predetermined arithmetic processing using the image data, and performs image comparison processing of various image data. Specifically, it performs decompression processing according to the compression method of the image data to be compared, and compares the decompressed images. The image processing unit 20 can determine whether the images match and how much the difference is.

[0022] In addition, the image processing unit 20 also performs processing such as superimposing an On-Screen Display (OSD) such as a menu or arbitrary characters to be displayed on the display unit 23 together with the image data for display.

[0023] In addition, the image processing unit 20 performs subject detection processing to detect a subject existing in the image data and detect the subject region by using the input image data, distance information from the subject obtained from the imaging element 13 at the time of shooting, and the like. As information that can be detected, region information such as the position and size in the image and detection information such as the inclination and probability can be obtained.

[0024] Furthermore, the image processing unit 20 includes a synthesis processing circuit for synthesizing multiple image data. In this embodiment, the image processing unit 20 may synthesize images by overwriting pixels, or by weighted addition. Weighted addition can produce an image in which the background is transparent. The image processing unit 20 can also perform a comparative light synthesis process or a comparative dark synthesis process, which selects the image with the brightest or darkest value in each region of the image data to be synthesized, and synthesizes the selected image for each pixel to generate a single image data.

[0025] The memory control unit 22 controls the A / D converter 15, timing generator 14, image processing unit 20, image display memory 24, D / A converter 21, and memory 25. The RAW image data generated by the A / D converter 15 is written to the image display memory 24 or memory 25 via the image processing unit 20 and the memory control unit 22, or directly via the memory control unit 22.

[0026] Image data for display written to the image display memory 24 is displayed on the display unit 23, which is composed of a TFT LCD or the like, via the D / A converter 21. By sequentially displaying the image data obtained by imaging using the display unit 23, it is possible to realize an electronic viewfinder function that displays live images.

[0027] Memory 25 has sufficient storage capacity to store a predetermined number of still images and a predetermined amount of video footage, and stores the captured still images and video footage. Memory 25 can also be used as a workspace for the system control unit 50.

[0028] The exposure control unit 40 controls the shutter 12, which has an aperture function. The exposure control unit 40 also has a flash metering function by working in conjunction with the flash 44. The focus control unit 41 adjusts the focus by driving a focus lens (not shown) included in the photographic lens 11 based on instructions from the system control unit 50. The zoom control unit 42 controls zooming by driving a zoom lens (not shown) included in the photographic lens 11. The flash 44 has an AF assist light projection function and a flash metering function.

[0029] The system control unit 50 controls the entire digital camera 100. The non-volatile memory 51 is an electrically erasable and recordable non-volatile memory, such as an EEPROM. The non-volatile memory 51 stores not only programs but also map information and other data.

[0030] The shutter switch 61 (SW1) turns ON during the operation of the shutter button 60 and instructs the start of operations such as AF processing, AE processing, AWB processing, and EF processing. The shutter switch 62 (SW2) turns ON when the operation of the shutter button 60 is completed and instructs the start of a series of shooting operations including exposure processing, development processing, and recording processing. In the exposure processing, the system control unit 50 controls the system to write the signal read from the image sensor 13 to the memory 25 as RAW image data via the A / D converter 15 and the memory control unit 22. In the development processing, the system control unit 50 uses calculations in the image processing unit 20 and the memory control unit 22 to develop the RAW image data written to the memory 25 and controls the system to write it to the memory 25 as image data. In the recording processing, the system control unit 50 reads the image data from the memory 25, compresses it using the image processing unit 20, stores the compressed image data in the memory 25, and then controls the system to write it to the external recording medium 91 via the card controller 90.

[0031] The control unit 63 is equipped with various buttons and touch panels. For example, the control unit 63 includes a power button, a menu button, a mode switch for switching between shooting mode / playback mode / other special shooting modes, a directional pad, a set button, a macro button, and a multi-screen playback page change button. In addition, the control unit 63 also includes, for example, a flash setting button, a single-shot / continuous-shot / self-timer switching button, a menu navigation + (plus) button, a menu navigation - (minus) button, a shooting quality selection button, an exposure compensation button, and a date / time setting button.

[0032] The metadata generation and analysis unit 70 generates various metadata, such as Exchangeable image file format (Exif) information, to be attached to the image data when recording image data to the external recording medium 91, based on the information at the time of shooting. Furthermore, when reading image data recorded on the external recording medium 91, the metadata generation and analysis unit 70 analyzes the metadata attached to the image data. Examples of metadata include various setting information at the time of shooting, image data information related to the image data, and characteristic information of the subject contained in the image data. Additionally, when recording moving image data, the metadata generation and analysis unit 70 can generate and attach metadata to each frame.

[0033] The power supply 80 consists of a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a Li battery, or an AC adapter, etc. The power control unit 81 supplies power from the power supply 80 to each part of the digital camera 100.

[0034] The card controller 90 transmits and receives data to and from an external recording medium 91, such as a memory card. The external recording medium 91 is, for example, a memory card, and records images (still images, videos) taken by the digital camera 100.

[0035] The communication unit 71 has a communication circuit for transmitting and receiving data. Specifically, the communication circuit may be configured to perform wireless communication such as Wi-Fi or Bluetooth (registered trademark), or it may be configured to perform wired communication such as Ethernet or USB.

[0036] The hash value generation unit 72 generates (calculates) a hash value by executing a hash function on various data (e.g., image data or metadata) input via the system control unit 50. Algorithms for generating hash values ​​include SHA256, SHA384, and SHA512. Note that the system control unit 50 may generate the hash value instead of the hash value generation unit 72. Furthermore, the hash value generation unit 72 may generate a hash value by executing a hash function on the entire image file, rather than just the image data.

[0037] The signature generation / verification unit 73 generates and verifies signature information necessary for determining authenticity. When an image is created, the signature generation / verification unit 73 generates signature information using the hash value of the image data generated by the hash value generation unit 72 and the signature generation key (private key), and records it in the image file as authenticity guarantee information. When image tampering is detected, the signature generation / verification unit 73 determines whether or not the image has been tampered with by verifying the hash value of the image data to be verified, generated by the hash value generation unit 72, and the signature recorded as authenticity guarantee information using the public key. Examples of algorithms for generating and verifying signature information include ECDSA, RSASSA-PSS, and EdDSA. Note that the system control unit 50 may perform the role of the signature generation / verification unit 73 instead of the signature generation / verification unit 73.

[0038] Figure 2A shows an example of the configuration of a composite image file. In this embodiment, a composite image (hereinafter sometimes simply referred to as a "composite image") means an image generated by combining multiple captured images corresponding to multiple exposures. The image file 200A recorded in this embodiment includes an area for recording metadata (Exif data 201) in accordance with the Exif standard, an area for recording compressed main image data 206, and an area for recording authenticity assurance information 223 (authenticity assurance information area 207).

[0039] For example, if the user instructs the image to be recorded in JPEG format, the thumbnail image data 205 and the main image data 206 will be recorded in JPEG format in the image file 200A. In addition, Exif data 201 will be recorded in the APP1 marker, etc., and the authenticity guarantee information area 207 will be recorded in the APP11 marker, etc.

[0040] Furthermore, if the user instructs the system to record in High Efficiency Image File Format (HEIF), the image file 200A will be recorded in HEIF format, and the Exif data 201 and authenticity information area 207 will be recorded in a MetaDataBox or similar location. Similarly, if the user instructs the system to record in RAW format, the Exif data 201 and authenticity information area 207 will also be recorded in a designated area such as a MetaDataBox.

[0041] Image file 200A may be recorded in formats other than those described above.

[0042] Exif data 201 may also record information 202 indicating the presence or absence of authenticity assurance information and a link 203 to the authenticity assurance information. Furthermore, the MakerNote 204 included in Exif data 201 may contain manufacturer-specific metadata generated using the metadata generation and analysis unit 70, which is generally kept confidential.

[0043] The authenticity assurance information area 207 includes authenticity assurance information 223 (first authenticity assurance information) which contains information to guarantee the authenticity of the image data 206. The authenticity assurance information 223 includes the action, Actor (name of the camera or software that generated the image), various hash values, thumbnail image data 224, and signature.

[0044] The action indicates (identifies) whether the image data 206 is a composite image of multiple images or a non-composite image (an image captured in a single exposure). If the image data 206 is a composite image of multiple images, the action has the value "Edit" (first information) as shown in Figure 2A. If the image data 206 is a non-composite image, the action has the value "Generate" (second information).

[0045] Thumbnail image data 224 is thumbnail image data corresponding to the main image data 206 at the time when authenticity assurance information 223 is added to the image file 200A.

[0046] The various hash values ​​include the hash value of the main image data 206, the hash value of the thumbnail image data 224, and the hash value of the metadata (Exif data 201 in the example in Figure 2A).

[0047] Thus, the authenticity assurance information 223 includes the hash values ​​of both the main image data 206 and the thumbnail image data 224, and these hash values ​​are signed. Therefore, the authenticity assurance information 223 can be used to guarantee the authenticity of the main image data 206 and the thumbnail image data 224 (if the authenticity is compromised, the signature verification will fail, so if the signature verification is successful, it is guaranteed that the main image data 206 and the thumbnail image data 224 are authentic).

[0048] Figure 2B shows another example of the configuration of a multi-image composite file. In the example in Figure 2A, the authenticity assurance information area 207 contains only one authenticity assurance information 223 (first authenticity assurance information), but as shown in Figure 2B, the authenticity assurance information area 207 may contain multiple authenticity assurance information (multiple second authenticity assurance information). In the example in Figure 2B, the authenticity assurance information area 207 contains three authenticity assurance information 217, 219, and 221 corresponding to the three source images used to generate the multi-image composite image, in addition to the authenticity assurance information 223 for guaranteeing the authenticity of the main image data 206, which is a multi-image composite image. The thumbnail image data 218, 220, and 222 stored in the authenticity assurance information 217, 219, and 221 are thumbnail image data corresponding to each source image at the time the authenticity assurance information was added to each captured source image. The thumbnail image data 224 stored in the authenticity assurance information 223 is, as in Figure 2A, a thumbnail image data corresponding to the composite image (main image data 206). Since the source image is a non-composite image, the action stored in the authenticity assurance information 217, 219, and 221 has the value "Generate".

[0049] In the example in Figure 2B, the latest authenticity information for the composite image is the fourth (bottommost) authenticity information, 223. When the system control unit 50 records multiple authenticity information in the authenticity information area 207, it may store management information at the beginning of the authenticity information area 207, such as a link to each authenticity information, the number of authenticity information entries, and information indicating which is the latest authenticity information. Alternatively, the system control unit 50 may record multiple authenticity information entries sequentially without recording management information in the authenticity information area 207, and treat the last recorded authenticity information as the latest authenticity information. Alternatively, the system control unit 50 may store information in the authenticity information area 207 indicating which authenticity information was added when the non-composite image was captured.

[0050] Authenticity assurance information 217 includes information to guarantee the authenticity of the source image and the thumbnail image (thumbnail image data 218) corresponding to the source image. The structure of authenticity assurance information 217 is the same as that of authenticity assurance information 223. However, the hash value of the main image data included in authenticity assurance information 217 is not the hash value of the main image data 206 of image file 200B, but the hash value of the source image data (main image data 206 in Figure 2C, described later) used to generate the main image data 206. Also, the hash value of the thumbnail image data included in authenticity assurance information 217 is the hash value of the thumbnail image data 218 corresponding to the source image data. The structure of authenticity assurance information 219 and 221 is the same as that of authenticity assurance information 217.

[0051] Since the image file 200B contains authenticity assurance information 217, 219, and 221, the digital camera 100 can verify the authentic origin of the composite image data 206. For example, the digital camera 100 can verify the authenticity of the thumbnail image data 218 corresponding to the source image data by verifying the signature of the hash value of the thumbnail image data in the authenticity assurance information 217.

[0052] Figure 2C shows an example of the structure of a non-composite image file. As shown in Figure 2C, the structure of image file 200C may be the same as the structure of image file 200A in Figure 2A. In the example in Figure 2C, it is assumed that image file 200C is an image file that stores the source image corresponding to the authenticity assurance information 217 in Figure 2B as the main image.

[0053] Figure 3 is a flowchart of the process for adding authenticity assurance information to an image. Here, we will describe the case in which a multi-image composite is generated by multiplexing three exposure images (non-composite images). Unless otherwise specified, the processing of each step in this flowchart is realized by the system control unit 50 executing a program stored in the non-volatile memory 51. In this embodiment, the number of source images used for synthesis is not limited to three. Also, the method of synthesizing the multiple source images (exposure images) is not limited to multiplexing, but may be other synthesis methods (for example, multi-shot HDR synthesis, multi-shot NR synthesis, multi-shot panorama synthesis, etc.).

[0054] The user can operate the control unit 63 to display the multiple image composition setting menu on the display unit 23, and set the number of images (source images) to be used for composition to three on the multiple image composition setting menu. After that, when the user takes three shots (exposures) with the digital camera 100, three source images (non-composite images) are generated, and a composite image based on the three source images is generated. Each time an image (non-composite image or composite image) is generated by the digital camera 100, the processing of this flowchart is performed on the generated image.

[0055] In S301, the system control unit 50 determines whether the setting for adding authenticity assurance information is ON. If the setting for adding authenticity assurance information is ON, the process proceeds to S302; otherwise, the process proceeds to S305.

[0056] It should be noted that the user has previously configured the authenticity guarantee information setting. For example, the user can display the settings menu on the display unit 23 by operating the control unit 63, and on the settings menu, they can select ON (enable) or OFF (disable) as the additional setting.

[0057] In S302, the system control unit 50 determines whether the image to be processed (the first image) is a composite image or not. If the image to be processed is a composite image, the process proceeds to S304; otherwise (if the image to be processed is not a composite image), the process proceeds to S303.

[0058] In S303, the system control unit 50 generates authenticity assurance information for the image to be processed (in this case, a non-composite image) using the hash value generation unit 72 and the signature generation / verification unit 73, and attaches (associates) the generated authenticity assurance information to the image to be processed. In this case, an image file like the image file 200C shown in Figure 2C is generated. Since the image to be processed is a non-composite image, the value "Generate" is set for the action stored in the authenticity assurance information 217, as shown in Figure 2C. In addition, the hash value generation unit 72 calculates the hash value of the main image data 206, the hash value of the thumbnail image data 218, and the hash value (not shown) of the metadata (Exif data 201), and these hash values ​​are stored in the authenticity assurance information 217.

[0059] In this example, since it is assumed that three source images will be captured, the process in S303 will be executed three times, and three source image files will be generated. For example, the second source image file has the file structure shown in Figure 2C, and its authenticity assurance information is the authenticity assurance information 219 shown in Figure 2B. Similarly, the third source image file has the file structure shown in Figure 2C, and its authenticity assurance information is the authenticity assurance information 221 shown in Figure 2B.

[0060] In S304, the system control unit 50 generates authenticity assurance information for the image to be processed (in this case, a composite image) using the hash value generation unit 72 and the signature generation / verification unit 73, and attaches (associates) the generated authenticity assurance information to the image to be processed. In this case, an image file like the image file 200A shown in Figure 2A is generated. Since the image to be processed is a composite image, the value "edit" is set for the action stored in the authenticity assurance information 223, as shown in Figure 2A. In addition, the hash value generation unit 72 calculates the hash value of the main image data 206, the hash value of the thumbnail image data 224, and the hash value (not shown) of the metadata (Exif data 201), and these hash values ​​are stored in the authenticity assurance information 223.

[0061] In S305, the system control unit 50 refrains from adding authenticity assurance information to the image to be processed.

[0062] In S306, the system control unit 50 saves an image file containing an image with authenticity assurance information attached (if S303 or S304 is passed) or an image without authenticity assurance information attached (if S305 is passed) to the external recording medium 91.

[0063] In the above explanation, it was assumed that the action in authenticity assurance information 223 has the value "edit" (first information), and the action in authenticity assurance information 217, 219, and 221 has the value "generate" (second information). Authenticity assurance information 217, 219, 221, and 223 identify whether the image whose authenticity should be guaranteed is a composite image or a non-composite image based on the value of the action. However, the method of configuring authenticity assurance information to identify whether an image is a composite image or a non-composite image is not limited to using the value of the action ("edit" or "generate"). For example, the action in authenticity assurance information 217, 219, and 221 may have the value "generate," while authenticity assurance information 223 may be configured not to include an action. In this case, the absence of an action in the authenticity assurance information means that the image is a composite image.

[0064] As described above, according to the first embodiment, the digital camera 100 associates the first image (for example, the main image data 206 in Figure 2A, or the main image data 206 in Figure 2C) with first authenticity assurance information (for example, authenticity assurance information 223 in Figure 2A, or authenticity assurance information 217 in Figure 2C) which includes information to guarantee the authenticity of the first image. The first authenticity assurance information is configured to identify whether the first image is a composite image (for example, the main image data 206 in Figure 2A) generated by combining multiple captured images corresponding to multiple exposures, or a non-composite image (for example, the main image data 206 in Figure 2C) captured in a single exposure.

[0065] Therefore, according to this embodiment, it is possible to distinguish whether an image associated with authenticity assurance information is a composite image or a non-composite image, and thus it becomes possible to associate appropriate authenticity assurance information with a composite image.

[0066] [Second Embodiment] In the first embodiment, as described in the explanation of S304 in Figure 3, an image file having the structure shown in Figure 2A is generated. In other words, in the first embodiment, only one authenticity assurance information 223 corresponding to the main image data 206 of the composite image is added to the composite image. In contrast, the second embodiment describes a case in which authenticity assurance information corresponding to the source images is also recorded as the provenance for the composite image.

[0067] In the second embodiment, the basic configuration of the digital camera 100 is the same as in the first embodiment. The following will mainly describe the differences from the first embodiment.

[0068] In the second embodiment, at S304 in Figure 3, the system control unit 50 acquires multiple authenticity assurance pieces of information (multiple second authenticity assurance pieces of information) corresponding to multiple captured images (non-composite images) used as source images. Each of the multiple authenticity assurance pieces of information acquired here is associated with one of the multiple captured images. Here, the number of source images (captured images) is assumed to be three. The system control unit 50 adds the three authenticity assurance pieces of information corresponding to the three captured images (non-composite images) as authenticity assurance pieces of information 217, 219, and 221 (multiple second authenticity assurance pieces of information) to the composite image. Since the source images are non-composite images, the action stored in the authenticity assurance pieces of information 217, 219, and 221 has the value "generate". The system control unit 50 also adds authenticity assurance piece of information 223 (first authenticity assurance piece of information) corresponding to the main image data 206 of the composite image to the composite image.

[0069] Thus, according to the second embodiment, it is possible to add authenticity assurance information 223 to the composite image, which includes the history of what source images were used to generate the composite image (authenticity assurance information 217, 219, 221), and has an action with the value "edit".

[0070] [Third Embodiment] In the first and second embodiments, three source images are captured when generating the composite image. However, the source images may be selected from pre-captured image files. In the third embodiment, a case is described in which a composite image is generated by using images from a pre-captured image file as source images.

[0071] In the third embodiment, the basic configuration of the digital camera 100 is the same as in the first embodiment. The following will mainly describe the differences from the first embodiment.

[0072] The external recording medium 91 is assumed to contain two or more image files, each containing a captured image (non-composite image). The user can select multiple image files (multiple source image files) to be used to generate a composite image from the two or more image files stored on the external recording medium 91 by operating the operation unit 63. Here, it is assumed that three image files are selected. The system control unit 50 generates a composite image from the captured images in the three image files by controlling the image processing unit 20. Once the composite image is generated, the flowchart in Figure 3 is performed on the composite image.

[0073] In the third embodiment, at S304 in Figure 3, the system control unit 50 determines whether or not authenticity assurance information has been added to the source image file.

[0074] If the source image file has authenticity assurance information attached to it to guarantee the authenticity of the source image, the system control unit 50 inherits the authenticity assurance information from the source image file and also adds authenticity assurance information to the composite image. As a result, an image file like the image file 200B shown in Figure 2B is generated. Alternatively, the system control unit 50 may add only the authenticity assurance information corresponding to the main image data of the composite image to the composite image without adding the authenticity assurance information from the source image file to the composite image. In this case, an image file like the image file 200A shown in Figure 2A is generated.

[0075] If authenticity assurance information is not attached to the source image file, the system control unit 50 refrains from attaching authenticity assurance information to the composite image.

[0076] Thus, according to the third embodiment, authenticity assurance information to guarantee the authenticity of the composite image is added to the composite image only when authenticity assurance information to guarantee the authenticity of the source image (non-composite image) is added to the source image. Therefore, according to this embodiment, it is possible to correctly record the origin information of the authenticity assurance information of the composite image.

[0077] [Other embodiments] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described 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., an ASIC) that implements one or more functions.

[0078] [summary] The embodiments described above disclose, but are not limited to, the inventions shown in at least the following items. (Item 1) The system includes association means for associating first authenticity assurance information, which includes information for guaranteeing the authenticity of the first image, with the first image. The first authenticity assurance information is configured to identify whether the first image is a composite image generated by combining multiple captured images corresponding to multiple exposures, or a non-composite image captured in a single exposure. An image processing apparatus characterized by the following: (Item 2) If the first image is the composite image, the first authenticity assurance information includes first information indicating that the first image is the composite image. If the first image is the non-composite image, the first authenticity assurance information includes second information indicating that the first image is the non-composite image. The image processing apparatus according to item 1, characterized in that it is a picture processing apparatus. (Item 3) If the first image is the composite image, the association means associates a plurality of second authenticity assurance information with the first image. The plurality of second authenticity assurance information includes a plurality of thumbnail images corresponding to the plurality of captured images, and information for guaranteeing the authenticity of the plurality of thumbnail images. The image processing apparatus according to item 1 or 2, characterized in that (Item 4) The aforementioned plurality of second authenticity assurance information includes information for ensuring the authenticity of the plurality of captured images, The image processing apparatus according to item 3, characterized in that (Item 5) The system further comprises a synthesis means for generating the first image, which is the synthesized image, by combining the plurality of captured images, When each of the multiple second authenticity assurance pieces is associated with a separate one of the multiple captured images, and each of the multiple second authenticity assurance pieces includes information for ensuring the authenticity of the corresponding captured image, the association means associates the first authenticity assurance piece with the first image which is the composite image. If each of the plurality of second authenticity assurance pieces is not associated with a separate one of the plurality of captured images, the association means refrains from associating the first authenticity assurance piece with the first image which is the composite image. The image processing apparatus according to item 1, characterized in that it is a picture processing apparatus. (Item 6) If each of the plurality of second authenticity assurance pieces of information is associated with a separate one of the plurality of captured images, the association means associates the plurality of second authenticity assurance pieces of information with the first image which is the composite image. The plurality of second authenticity assurance information includes a plurality of thumbnail images corresponding to the plurality of captured images, and information for guaranteeing the authenticity of the plurality of thumbnail images. The image processing apparatus according to item 5, characterized in that... (Item 7) The system further includes a selection means that, in accordance with user instructions, selects multiple image files from a recording medium that stores two or more image files, each containing a captured image. The synthesis means generates the first image, which is the synthesized image, by combining the multiple captured images contained in the multiple image files. The image processing apparatus according to item 5 or 6, characterized in that... (Item 8) An image processing apparatus described in any one of items 1 to 7, A shooting means for capturing the aforementioned multiple images, An imaging device characterized by comprising: (Item 9) A control method performed by an image processing device, The process includes an association step of associating first authenticity assurance information, which includes information for guaranteeing the authenticity of the first image, with the first image. The first authenticity assurance information is configured to identify whether the first image is a composite image generated by combining multiple captured images corresponding to multiple exposures, or a non-composite image captured in a single exposure. A control method characterized by the following: (Item 10) A program for causing a computer to function as one of the means of an image processing apparatus as described in any one of items 1 through 7.

[0079] The 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, claims are attached to disclose the scope of the invention. [Explanation of symbols]

[0080] 13…Image sensor, 20…Image processing unit, 25…Memory, 50…System control unit, 51…Non-volatile memory, 63…Operation unit, 72…Hash value generation unit, 73…Signature generation / verification unit

Claims

1. The system includes association means for associating first authenticity assurance information, which includes information for guaranteeing the authenticity of the first image, with the first image. The first authenticity assurance information is configured to identify whether the first image is a composite image generated by combining multiple captured images corresponding to multiple exposures, or a non-composite image captured in a single exposure. An image processing apparatus characterized by the following:

2. If the first image is the composite image, the first authenticity assurance information includes first information indicating that the first image is the composite image. If the first image is the non-composite image, the first authenticity assurance information includes second information indicating that the first image is the non-composite image. The image processing apparatus according to feature 1.

3. If the first image is the composite image, the association means associates a plurality of second authenticity assurance pieces of information with the first image. The plurality of second authenticity assurance information includes a plurality of thumbnail images corresponding to the plurality of captured images, and information for guaranteeing the authenticity of the plurality of thumbnail images. The image processing apparatus according to feature 1.

4. The aforementioned plurality of second authenticity assurance information includes information for ensuring the authenticity of the plurality of captured images, The image processing apparatus according to claim 3.

5. The system further comprises a synthesis means for generating the first image, which is the composite image, by combining the plurality of captured images, When each of the multiple second authenticity information is associated with a separate one of the multiple captured images, and each of the multiple second authenticity information includes information for guaranteeing the authenticity of the corresponding captured image, the association means associates the first authenticity information with the first image which is the composite image. If each of the plurality of second authenticity assurance information is not associated with a separate one of the plurality of captured images, the association means refrains from associating the first authenticity assurance information with the first image which is the composite image. The image processing apparatus according to feature 1.

6. If each of the plurality of second authenticity information is associated with a separate one of the plurality of captured images, the association means associates the plurality of second authenticity information with the first image which is the composite image. The plurality of second authenticity assurance information includes a plurality of thumbnail images corresponding to the plurality of captured images, and information for guaranteeing the authenticity of the plurality of thumbnail images. The image processing apparatus according to feature 5.

7. The system further includes a selection means that, in accordance with user instructions, selects multiple image files from a recording medium that stores two or more image files, each containing a captured image. The synthesis means generates the first image, which is the synthesized image, by combining the multiple captured images contained in the multiple image files. The image processing apparatus according to feature 5.

8. An image processing apparatus according to any one of claims 1 to 7, A shooting means for capturing the aforementioned multiple images, An imaging device characterized by comprising:

9. A control method performed by an image processing device, The system includes an association step of associating first authenticity assurance information, which includes information for guaranteeing the authenticity of the first image, with the first image. The first authenticity assurance information is configured to identify whether the first image is a composite image generated by combining multiple captured images corresponding to multiple exposures, or a non-composite image captured in a single exposure. A control method characterized by the following:

10. A program for causing a computer to function as one of the means of an image processing apparatus according to any one of claims 1 to 7.

Images