Display control device, method executed by the display control device, and program

Abstract

This technology provides improved data display processing capabilities for detecting tampering in video data. [Solution] The display control device (client device 200) receives video data transmitted from the video transmission device (camera 100) (S402). The display control device also receives metadata indicating the results of the analysis of the video data (S405). The display control device performs tamper detection processing on the received video data (S403), and controls the display of the metadata based on the results of the tamper detection processing (S406).

Description

Technical Field

[0001] The present disclosure relates to an information display technique in the verification of video forgery.

Background Art

[0002] Conventionally, there has been a technique for detecting forgery of video data. In the Open Network Video Interface Forum, which is a standard regarding the connection between an imaging device (camera) and a client device, standardization is progressing on a method of attaching data related to forgery detection to video data. The Open Network Video Interface Forum is hereinafter referred to as ONVIF.

[0003] In ONVIF, on the imaging device side, it is being considered to attach a digital signature based on the hash value of video data to the SEI included in the NALunit of an encoding method such as H.264 or H.265 and transmit it. And on the client device side, it is being considered to determine whether forgery has occurred by comparing the received digital signature with the hash value of the video data. NALunit is the Network Abstraction Layer Unit. SEI is an abbreviation for Supplemental Enhancement Information.

[0004] Regarding the technique for detecting forgery of video data, Patent Document 1 describes displaying the verification result of the presence or absence of forgery of video data on a display. Also, Patent Document 1 discloses that when the video data has not been forged, the video data is displayed on the display, and when it has been forged, the video data is not output to the display.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In detecting tampering with such video data, there is a desire for more user-friendly data display processing, and the technology described in Patent Document 1 has room for improvement.

[0007] This disclosure provides a data display processing technology that improves the convenience of detecting tampering in video data. [Means for solving the problem]

[0008] A display control device according to one embodiment of the present disclosure includes: a first receiving means for receiving video data transmitted from a video transmitting device; a second receiving means for receiving metadata transmitted from the video transmitting device and indicating the results of analysis of the video data; a detection means for performing tamper detection processing on the received video data; and a control means for controlling the display of the metadata based on the results of the tamper detection processing. [Effects of the Invention]

[0009] According to this disclosure, it is possible to perform data display processing that improves convenience in detecting tampering with video data. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows an example of a video distribution system. [Figure 2] This is a block diagram showing an example of a camera configuration. [Figure 3] This block diagram shows the configuration of the client device. [Figure 4] This is a sequence diagram showing an example of processing for the camera and client device in the first embodiment. [Figure 5] This flowchart shows an example of tamper detection processing by a client device. [Figure 6](A) and (B) show examples of how metadata can be displayed, respectively. [Figure 7] This flowchart shows an example of processing by a client device in the second embodiment. [Figure 8] (A)-(D) show examples of display data from the client device, corresponding to the processing results in Figure 7. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described below with reference to the drawings. Not all of the features in the embodiments of this disclosure are essential, and features may be combined in any way. Furthermore, the configurations shown in the following embodiments are merely examples, and this disclosure is not limited to the illustrated configurations. In the drawings, the same or similar components are denoted by the same reference numerals to avoid redundant explanations.

[0012] [First Embodiment] Hereinafter, a video distribution system including a display control device in a first embodiment of this disclosure will be described with reference to Figures 1-6. Figure 1 is a diagram showing an example of a video distribution system. The video distribution system comprises a camera 100 and a client device 200. The camera 100 and the client device 200 are connected in a manner that allows them to communicate with each other via a network 300. The camera 100 is an example of a video transmission device. The client device 200 is an example of a device including a display control device.

[0013] The imaging device, camera 100, transmits video and metadata to the client device 200 via the network 300. The client device 200 performs tampering detection and other operations based on the received video.

[0014] Metadata is data indicating, for example, the result of video analysis by camera 100 and can be generated by camera 100. Metadata includes information about an object, such as the type of the object and the detection position of the object within the angle of view. Further, when the type of the main object is a person, the metadata may include features of the person, the background of the person, and / or the number of people. Examples of features of a person include the form of the face (such as the shape of the face, expression, and / or color), height, body type, clothing, and / or posture.

[0015] Network 300 is a communication network realized by, for example, any one of a LAN, a WAN, a telephone line, a dedicated digital line, ATM, a frame relay line, a cable TV line, a wireless line for data broadcasting, or a combination of two or more of them.

[0016] The configuration of the video distribution system shown in FIG. 1 is merely an example and is applicable to other devices as well. For example, the video distribution system may further include a distribution server (not shown) connected to network 300, and the distribution server may have a function as a video transmission device. Further, this distribution server may perform analysis of the video captured by camera 100 and generation of metadata based thereon. Alternatively, an external device (not shown) connected directly to camera 100 or via a network may perform analysis of the video and analysis of the metadata. In these cases, the distribution server or the external device transmits the metadata generated via network 300 to client device 200.

[0017] FIG. 2 is a block diagram showing an example of the configuration of camera 100. Camera 100 includes a control unit 101, a communication unit 102, an imaging unit 103, an imaging mechanism 104, a storage unit 105, and an encoding unit 106. Among these blocks, mainly encoding unit 106 is realized by software. However, at least some functions of encoding unit 106 may be realized by hardware.

[0018] The control unit 101 is a processor such as a CPU (Central Processing Unit) that controls the entire camera 100, and issues processing instructions to each part within the camera 100.

[0019] The communication unit 102 receives, via the network 300, change commands and control commands for changing various setting values from the client device 200. Also, the communication unit 102 transmits various data such as responses (responses) to each command, in addition to video data, to the client device 200. As an example, the commands are commands compliant with the ONVIF standard, but commands compliant with various other standards can also be used.

[0020] The imaging unit 103 performs imaging of a subject and conversion of the captured signal into an electrical signal. The imaging unit 103 further performs predetermined image processing and compression encoding processing on the electrical signal, and generates video data (image data).

[0021] The imaging mechanism 104 may have a pan mechanism, a tilt mechanism, and a zoom mechanism for controlling the imaging direction and the angle of view.

[0022] This is the storage unit 105. It is used as a storage area for various data, mainly for storing programs executed by the control unit 101, a work area during program execution, and temporarily storing video data generated by the imaging unit 103 described later. The storage unit 105 includes, for example, RAM and ROM, and may also include a flash memory or an SSD (Solid State Drive). Alternatively, the storage unit 105 may include a magnetic storage device.

[0023] The encoding unit 106 compresses and encodes the video data captured by the imaging unit 103 based on a format compliant with standards such as H.264 or H.265. Other compression encoding methods compliant with arbitrary standards such as AV1 or H.266 can also be used. When performing compression encoding, the encoding unit 106 calculates a hash value of the video data and creates a digital signature by encrypting the hash value. The encoding unit 106 adds the generated digital signature to the video data as data for tamper detection, for example, by writing it to the SEI included in the NALunit.

[0024] The encoding unit 106 generates a pair of public and private keys. This public and private key pair is used to create a digital signature and is uniquely generated by the camera 100. The generated public key data is transmitted to the client device 200 via the communication unit 102.

[0025] The following describes the more detailed functions and operation of the encoding unit 106. The encoding unit 106 generates a hash value based on features extracted from the video data as described above. Specifically, the encoding unit 106 first extracts features from each frame of the video. These features can be brightness, contrast, edge information, color distribution, or other visual features of the image, and any features can be used. The video features used here may be selected based on the content of the video. Next, the encoding unit 106 combines the extracted features as needed to generate a unique hash value. The encoding unit 106 encrypts the generated hash value using a secret key. The encrypted hash value functions as a digital signature and is transmitted to the video data and the client device. Then, such a digital signature is generated for each frame, as an example, and attached to the video data. Alternatively, as another example, a digital signature may be attached to each GOP (Group Of Picture). The video data generated as described above is output to the storage unit 105 and temporarily stored.

[0026] As described later, if a tampering detection method is used in which the video transmitting side does not need to add data for detecting tampering to the video data, the camera 100 does not necessarily need to generate a digital signature and add a digital signature to the video data as described above.

[0027] Furthermore, at least some of the above functions and operations of the encoding unit 106 may be performed by another configuration. For example, the control unit 101 may be the one performing these functions.

[0028] The configuration of camera 100 has been described above using Figure 2, but the processing block shown in Figure 2 is merely an example of a preferred embodiment of the video transmission device in this disclosure, and is not limited to this. Camera 100 can be modified and changed in various ways within the scope of the gist of this disclosure, such as by including a video analysis unit, an audio input unit, and an audio output unit.

[0029] Figure 3 is a block diagram showing the configuration of the client device 200. The client device 200 includes a control unit 201, a storage unit 202, a display control unit 203, an input unit 204, a communication unit 205, and a tamper detection unit 206. Of these blocks, the tamper detection unit 206 is mainly implemented by software. However, at least some of the functions of the tamper detection unit 206 may be implemented by hardware. The tamper detection unit 206 is an example of a detection means that performs tamper detection processing on at least the received video data.

[0030] The control unit 201 is composed of, for example, a CPU and controls the entire client device 200. The storage unit 202 is mainly used as a storage area for programs executed by the control unit 201, a work area during program execution, and information on connectable cameras currently present on the network 300, among other things. The storage unit 202 includes, for example, RAM and ROM, and may further include flash memory, SSD, or magnetic storage device.

[0031] The display control unit 203 displays various setting screens, data acquisition screens, a viewer for video received from the camera 100, and various messages on a display unit (not shown). The display unit is implemented, for example, by an LCD display or an organic EL display. The display control unit 203 is primarily an example of a control means that controls the display of at least the metadata based on the results of the tamper detection process. In addition to the display control unit 203, the control unit 201 can also be an example of such a control means.

[0032] The input unit 204 is implemented, for example, by a keyboard, buttons, a directional pad, a touch panel, a mouse, and its input interface, and transmits user operation information to the control unit 201. The user may also perform operations while looking at the user interface displayed on the display unit.

[0033] The communication unit 205 transmits various commands, including a command to start recording video, to the camera 100 via the network 300. The communication unit 205 also receives responses to the transmitted commands and video data from the camera 100. The communication unit 205 is an example of a receiving means (first receiving means, second receiving means) for receiving video data and metadata, and also an example of a transmitting means for sending commands.

[0034] The tamper detection unit 206 determines whether the video data received from the camera 100 has been tampered with. It determines whether the video data has been tampered with by methods such as comparing the data contained in the NALunit of the video data received from the camera 100 with the hash value calculated from the video data. The tamper detection unit 206 also obtains a digital signature based on the hash value attached to the video data received from the camera 100. In addition, the tamper detection unit 206 obtains the public key data in advance via the communication unit 205. The tamper detection method using digital signatures will be described later.

[0035] As mentioned above, the data for detecting tampering (digital signature based on hash values) does not necessarily have to be attached to the video data. In that case, the tampering detection unit 206 uses a tampering detection method that does not use data such as hash values, specifically a method that detects tampering by analyzing the video data. Several such methods are given below as examples.

[0036] For example, the tampering detection unit 206 may detect tampering using a technique based on compression artifacts. This technique determines whether or not tampering has occurred by analyzing artifacts related to the compression history of the video data. This technique uses an algorithm that detects specific patterns or noise discontinuities that occur during compression. In particular, non-uniformity of the quantization matrix and the presence of unnatural edges at block boundaries serve as indicators of tampering.

[0037] Alternatively, the tampering detection unit 206 may detect tampering by analyzing the noise pattern of the image. This technique uses sensor noise and patterns in image processing to detect whether the image has been tampered with. This technique analyzes the noise characteristics inherent to the camera sensor and determines that there is a high probability of tampering if these characteristics are inconsistent across each frame of the image. In this case, an example of a noise characteristic is PRNU (Photo Response Non-Uniformity).

[0038] Alternatively, the tampering detection unit 206 may detect tampering using a machine learning-based detection technique. This technique uses a machine learning model to learn and identify characteristic artifacts produced by various tampering methods. In particular, this technique trains convolutional neural networks (CNNs) or generative counter-aggregates (GANs) to detect tampered videos with high accuracy. This method trains the model using a large amount of legitimate video data and tampered video data, achieving robust detection performance even with new data.

[0039] Alternatively, the tampering detection unit 206 may detect tampering using a detection technique based on multimodal analysis. This technique can improve the accuracy of tampering detection by simultaneously analyzing multiple features of the video data. By combining and analyzing information such as video image quality indicators, audio frequency spectra, and metadata, it provides multiple clues necessary for identifying tampering.

[0040] As described above, the tampering detection unit 206 can detect tampering by analyzing the received video data. The tampering detection unit 206 can also utilize various other tampering detection technologies.

[0041] The tampering detection unit 206 can perform metadata tampering detection processing in the same manner as video data tampering detection processing, based on a digital signature generated based on the metadata, or by analyzing the metadata.

[0042] The configuration of the client device 200 has been described above using Figure 3, but the processing block shown in Figure 3 is merely an example of a preferred embodiment of the display control device in this disclosure, and is not limited to this. Various modifications and changes are possible within the scope of the gist of this disclosure, such as configurations that include an image analysis unit and a recording unit. As shown in Figure 3, a device having at least a part of the blocks that constitute the client device 200 may be provided as a separate device from the client device. For example, a device that receives video data and metadata from the camera 100 and a device that performs tamper detection processing and controls the display according to the result of the detection processing may be provided separately.

[0043] Figure 4 is a sequence diagram showing an example of processing by the camera 100 and client device 200, including video tampering detection processing, in this embodiment.

[0044] In step S401, the control unit 201 of the client device 200 sends a command (transmission start request) to the camera 100 via the communication unit 205 to start transmitting video data. This command may be, for example, a command compliant with the ONVIF standard. Alternatively, it may be a method of requesting transmission via RTP using an RTSP command, or other methods may be used. Note that RTSP stands for Real Time Streaming Protocol, and RTP stands for Real-time Transport Protocol.

[0045] When the control unit 101 of the camera 100 receives a transmission start request command, it determines whether or not video distribution (transmission) is possible with the settings included in the transmission start request, and responds with the result of that determination. In other words, the camera 100 sends a response indicating the determination result to the client device 200.

[0046] If transmission is possible with the settings included in the transmission start request, in S402, the control unit 101 of the camera 100 starts transmitting video data with the settings included in the transmission start request via the communication unit 102, and the client device 200 receives it. This video data is accompanied by data for tamper detection as needed. As an example, the transmission of video data is performed in stream format, but is not limited to this. For example, the video data may be transmitted in file format or as still images.

[0047] In S403, the tampering detection unit 206 of the client device 200 detects whether the received video data has been tampered with. Any one of the above-described methods can be used for tampering detection. Multiple tampering detection methods may also be combined.

[0048] Figure 5 is a flowchart showing an example of the tampering detection process in S403. This method uses digital signatures.

[0049] After receiving the video in S501, in S502, the tamper detection unit 206 decrypts the encrypted digital signature attached to the received video data using the public key previously received from the camera 100. This decryption yields a hash value based on the video data generated by the camera 100. As an example, the encrypted digital signature is obtained from the SEI of the video data.

[0050] In S503, the tamper detection unit 206 applies the same hash function used by the camera 100 to the received video data and calculates a hash value.

[0051] In S504, the tamper detection unit 206 compares the hash value (data obtained by decrypting the digital signature) attached to the received video data with the hash value calculated from the received video data. If the hash values ​​match in S504, it is determined that there has been no tampering.

[0052] On the other hand, in S504, if the hash value assigned to the video data does not match the hash value calculated from the video data, the tampering detection unit 206 determines in S505 that the video has been tampered with. Then, in S404 in Figure 4, the control unit 201 sends a request command to the camera 100 via the communication unit 205 to request metadata.

[0053] In S404, if the client device 200 sends a command to the camera 100 requesting the transmission of metadata, the camera 100 sends the metadata to the client device 200 as a response. Then, in S405, the client device 200 receives the transmitted metadata.

[0054] In S406, the display control unit 203 of the client device 200 superimposes the received metadata onto the video data. Figures 6(A) and 6(B) show examples of how metadata is displayed. As in Figure 6(A), the metadata may be superimposed on the video data as text, or as in Figure 6(B), it may be displayed as a figure that imitates an object (in this example, a person). For example, a simplified figure may be used as the figure that imitates the object. As mentioned above, the figure that imitates the object can be generated from information about the object (i.e., metadata). In the example of Figure 6(A), a rectangular dashed line is also displayed surrounding the position where the object (in this example, a person) is displayed on the video, and the metadata text is displayed inside the dashed rectangle.

[0055] On the other hand, if it is determined in S504 that the video has not been tampered with, the processing in S404-S406 will not be performed.

[0056] As described above, the processes shown in Figures 4, 5, and 6 can be appropriately selected or omitted depending on their purpose and the problem they aim to solve.

[0057] As described above, the display control unit 203 of the client device 200 in this embodiment controls the display of video data and metadata on the display unit based on the results of the tampering detection process. This enables data display processing that is even more convenient for the user. For example, in the technology described in Patent Document 1, if the video data has been tampered with, the video is not displayed on the display, so the user cannot check the situation at the shooting site and even in urgent situations it is necessary to disconnect the connection with the camera 100 (stop sending and receiving video). In contrast, as shown in Figures 6(A) and (B), the client device 200 displays metadata indicating the video content even when the video data is not displayed. This allows the user to understand the situation at the shooting site and improves convenience. In addition, since there is no need to stop sending and receiving video and to reconnect for reception, the user's effort is reduced.

[0058] [Modified version of the first embodiment] The processes shown in Figures 4-6 illustrate an example of a preferred embodiment of the internal processing of the client device 200 in this disclosure, and various modifications and changes are possible within the scope of the gist of this disclosure. For example, the metadata is not limited to those shown in Figures 6(A) and (B), but may display various characters, graphics, symbols, their colors, or combinations thereof.

[0059] In S403 of Figure 4, if the video has been tampered with, the client device 200 requests and receives the transmission of metadata in S404 and S405. However, in S402, the camera 100 may also transmit metadata when transmitting video, and the client device 200 may receive both the transmitted video data and metadata (similar to S701 and 702 in the second embodiment described later). In this case, in S403, the client device 200 performs a detection process for tampering with at least one of the received video data and metadata.

[0060] [Second Embodiment] In the second embodiment, the process for detecting tampering with video and metadata will be described below. In this embodiment, the description of the same configuration and functions as in the first embodiment will be omitted, and the differences will be described. The network configuration in Figure 1, the internal configuration of the camera 100 in Figure 2, and the internal configuration of the client device 200 in Figure 3 are the same as in the first embodiment.

[0061] Figure 7 is a flowchart showing an example of processing by the client device 200. In S701, the control unit 201 of the client device 200 receives video data from the camera 100 via the communication unit 205. This video data is supplemented with data for tamper detection as needed. As an example, the video data is transmitted in stream format, but this is not the only format.

[0062] In S702, the control unit 201 receives metadata from the camera 100 via the communication unit 205. This metadata is accompanied by data for tamper detection as needed.

[0063] In S706-S709, the control unit 201 modifies the processing according to the results of the determination process in S703-S705. In S703-S705, the tamper detection unit 206 of the client device 200 detects whether the received video data and metadata have been tampered with. The method for detecting tampering of the video data and metadata may be one of the multiple methods described above, or a combination of multiple methods.

[0064] If video tampering is detected in S703 and metadata tampering is detected in S704, in S706, the control unit 201 sends a command to the camera 100 via the communication unit 205 requesting that the transmission of video data be stopped. The camera 100 receives this command and stops transmitting video data. Next, the control unit 201 sends a command to the camera 100 requesting that the acquisition of metadata be stopped. The camera 100 receives this command and stops acquiring metadata. The control unit 201 does not necessarily have to send this command requesting that the transmission of video and / or metadata be stopped. For example, the display control unit 203 of the client device 200 may prevent the display of video and metadata.

[0065] The two screen examples shown in Figure 8(A) represent the display data of the client device 200 in S706. In these two screen examples, the display control unit 203 displays a message notification at the bottom of the blacked-out screen. These messages indicate that the video data has been tampered with, or that the metadata has been tampered with.

[0066] If video tampering is detected in S703, and metadata tampering is not detected in S704, then in S707, the control unit 201 sends a command to the camera 100 via the communication unit 205 requesting that the transmission of video data be stopped. Stopping the transmission of video data means that the client device 200 stops acquiring video data. Upon receiving this command, the camera 100 stops transmitting video data. Alternatively, the control unit 201 may receive the video data, but the display control unit 203 may choose not to display it. The display control unit 203 then superimposes the metadata received in S702 onto the video.

[0067] The three screen examples shown in Figure 8(B) each illustrate the display data of the client device 200 in S707. In these three screen examples, the display control unit 203 displays a message notification at the bottom of the blacked-out screen. The display control unit 203 also displays the received metadata in text, along with a dashed line surrounding the location of the object in the video. The message basically indicates that the video data has been tampered with, and may further include information indicating that the metadata is trustworthy, for example.

[0068] If no video tampering is detected in S703, and metadata is tampered with in S705, in S708, the control unit 201 sends a command to the camera 100 via the communication unit 205 requesting that the transmission of metadata be stopped. Stopping the transmission of metadata means that the client device 200 stops acquiring video data. Upon receiving this command, the camera 100 stops transmitting metadata. In S708, the control unit 201 may receive the metadata, but the display control unit 203 may not display it (i.e., not overlay the metadata on the video).

[0069] The three screen examples shown in Figure 8(C) each illustrate the display data of the client device 200 in S708. In these three screen examples, the display control unit 203 displays a message notification at the bottom of the received video. The message indicates at least that the metadata is unreliable and may further include content indicating, for example, that the video may be tampered with later.

[0070] If no video tampering is detected in S703 and no metadata tampering is detected in S705, then in S709, the display control unit 203 displays the video data received in S701.

[0071] The two screen examples shown in Figure 8(D) each show the display data of the client device 200 in S709. As shown on the left of Figure 8(D), the display control unit 203 may display a message at the bottom of the screen indicating that the reception and display of video data are working correctly.

[0072] The process shown in Figure 7 illustrates an example of a preferred embodiment of the internal processing of the client device 200 in this disclosure, and various modifications and changes are possible within the scope of the gist of this disclosure.

[0073] For example, in the explanation in Figure 7, metadata was received after the video data was received (S701) but before the video data tampering detection process (S703) was performed (S702). Alternatively, as shown in Figure 4, the client device 200 may receive metadata only after the tampering detection process for the received video data has been performed and tampering has been detected (S402-S404).

[0074] The client device 200 may perform the tampering detection process for metadata before the tampering detection process for video data.

[0075] [Other embodiments] The client device 200 may choose not to perform tampering detection on the video data, but only on the metadata. In this case as well, the tampering detection unit 206 will perform tampering detection on the metadata by analyzing the digital signature attached to the metadata or by analyzing the metadata itself. If the client device 200 determines that the metadata has been tampered with, it may assume that the video data has also been tampered with and request that the transmission of the video data be stopped, or it may choose not to display the video.

[0076] This disclosure can also be implemented by supplying a program that implements one or more of the functions of the embodiments described above 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 implemented by a circuit (e.g., an ASIC or FPGA) that implements one or more functions.

[0077] This embodiment includes the following configurations, methods, and programs. (Composition 1) A first receiving means for receiving video data transmitted from a video transmission device, A second receiving means that receives metadata transmitted from the video transmission device and indicating the results of the analysis of the video data, A detection means that performs tampering detection processing on the received video data, The system includes a control means for controlling the display of the metadata based on the results of the tampering detection process. A display control device characterized by the following: (Configuration 2) The control means performs control to stop displaying the video data if tampering with the video data is detected. A display control device according to configuration 1, characterized by the above. (Composition 3) The detection means further performs tampering detection processing on the metadata, If no tampering with the metadata is detected, the control means performs control to display the metadata while the display of the video data is stopped. The display control device according to configuration 2, characterized in that... (Composition 4) The detection means further performs tampering detection processing on the metadata, The control means, if no tampering with the video data is detected but tampering with the metadata is detected, performs the control to display the video data and stop displaying the metadata. A display control device according to configuration 1, characterized by the above. (Composition 5) The system further includes a transmission means for sending a command to the video transmission device based on the results of the tampering detection process. A display control device according to configuration 1, characterized by the above. (Composition 6) If the transmission means detects tampering with the video data, it sends a command to the video transmission device requesting that the transmission of the video data be stopped. The display control device according to configuration 5, characterized by the features described herein. (Composition 7) The detection means further performs tampering detection processing on the metadata, If no tampering with the metadata is detected, the control means performs control to display the metadata while the display of the video data is stopped. The display control device according to configuration 6, characterized in that... (Composition 8) The detection means further performs tampering detection processing on the metadata, If tampering with the video data is not detected, but tampering with the metadata is detected, the control means displays the video data, and the transmission means sends a command to the video transmission device requesting that the transmission of the metadata be stopped. The display control device according to configuration 5, characterized by the features described herein. (Composition 9) If the transmission means detects tampering with the video data, it sends a command to the video transmission device requesting the transmission of the metadata. The second receiving means receives the metadata transmitted from the video transmission device in response to a command requesting the transmission of the metadata. A display control device according to any one of configurations 5 to 7, characterized in that it is a display control device. (Composition 10) The video data includes a digital signature generated based on the video data, The detection means performs a detection process for tampering with the video data based on the digital signature generated from the video data. A display control device according to any one of configurations 1 to 9. (Composition 11) The metadata includes a digital signature generated based on the metadata, The detection means performs a detection process for tampering with the metadata based on the digital signature generated based on the metadata. A display control device according to any one of configurations 1 to 10, characterized in that it is a display control device. (Composition 12) The detection means performs a detection process for tampering with the video data by analyzing the video data. A display control device according to any one of configurations 1 to 9. (Composition 13) The detection means performs a detection process for tampering with the metadata by analyzing the metadata. A display control device according to any one of configurations 1 to 9 and 12. (method) A first receiving step which receives video data transmitted from a video transmission device, A second receiving step, which receives metadata transmitted from the video transmission device and indicating the results of the analysis of the video data, A detection step in which tampering detection processing is performed on the received video data, The process includes a control step that controls the display of the metadata based on the results of the tampering detection process. A method performed by a display control device, characterized in that... (program) A program that causes a computer to perform each of the steps described in the above method. [Explanation of symbols]

[0078] 100: Camera 103: Imaging Unit 106: Encoding section 200: Client device 201: Control Unit 203: Display Control Unit 205: Communications Department 206: Tampering Detection Unit

Claims

1. A first receiving means for receiving video data transmitted from a video transmission device, A second receiving means that receives metadata transmitted from the video transmission device and indicating the results of the analysis of the video data, A detection means that performs tampering detection processing on the received video data, The system includes a control means for controlling the display of the metadata based on the results of the tampering detection process. A display control device characterized by the following:

2. The control means performs control to stop displaying the video data if tampering with the video data is detected. The display control device according to feature 1.

3. The detection means further performs tampering detection processing on the metadata, If no tampering with the metadata is detected, the control means performs control to display the metadata while the display of the video data is stopped. The display control device according to claim 2.

4. The detection means further performs tampering detection processing on the metadata, The control means, if no tampering with the video data is detected but tampering with the metadata is detected, performs the control to display the video data and stop displaying the metadata. The display control device according to feature 1.

5. The system further includes a transmission means for sending a command to the video transmission device based on the results of the tampering detection process. The display control device according to feature 1.

6. If the transmission means detects tampering with the video data, it sends a command to the video transmission device requesting that the transmission of the video data be stopped. The display control device according to claim 5.

7. The detection means further performs tampering detection processing on the metadata, If no tampering with the metadata is detected, the control means performs control to display the metadata while the display of the video data is stopped. The display control device according to feature 6.

8. The detection means further performs tampering detection processing on the metadata, If tampering with the video data is not detected, but tampering with the metadata is detected, the control means displays the video data, and the transmission means sends a command to the video transmission device requesting that the transmission of the metadata be stopped. The display control device according to claim 5.

9. If the transmission means detects tampering with the video data, it sends a command to the video transmission device requesting the transmission of the metadata. The second receiving means receives the metadata transmitted from the video transmission device in response to a command requesting the transmission of the metadata. The display control device according to claim 5.

10. The video data includes a digital signature generated based on the video data, The detection means performs a detection process for tampering with the video data based on the digital signature generated from the video data. The display control device according to feature 1.

11. The metadata includes a digital signature generated based on the metadata, The detection means performs a detection process for tampering with the metadata based on the digital signature generated based on the metadata. The display control device according to feature 1.

12. The detection means performs a detection process for tampering with the video data by analyzing the video data. The display control device according to feature 1.

13. The detection means performs a detection process for tampering with the metadata by analyzing the metadata. The display control device according to feature 1.

14. A first receiving step which receives video data transmitted from a video transmission device, A second receiving step involves receiving metadata transmitted from the video transmission device, which indicates the results of the analysis of the video data. A detection step in which tampering detection processing is performed on the received video data, The process includes a control step that controls the display of the metadata based on the results of the tampering detection process. A method performed by a display control device, characterized in that...

15. A program that causes a computer to perform each of the steps described in claim 14.

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