Photography obstruction detection device, photography obstruction detection system, and photography obstruction detection program

Abstract

To provide a technique for improving the precision of determination on whether photography by an imaging device is obstructed.SOLUTION: A photography obstruction detection device 100 comprises: an estimation information acquisition part 110 which acquires a plurality of pieces of obstruction information showing estimation results of whether a corresponding imaging device among a plurality of imaging devices 11-1, 11-2, ..., 11-N, classified into a plurality of sets according to illuminance environments where they are installed; and an obstruction specification part 160 which specifies whether a first imaging device is obstructed in photography, based upon obstruction estimation information corresponding to the first imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N among the plurality of pieces of obstruction estimation information that the estimation information acquisition part 110, and obstruction estimation information corresponding to a second imaging device belonging to the same set with the first imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a photography tampering detection device. [Background technology]

[0002] For example, if the photographing lens is covered by an object, the imaging device cannot photograph the subject normally (hereinafter, the inability of the imaging device to photograph the subject normally is referred to as photographing interference). Therefore, the photographing interference detection device estimates whether or not the imaging device is being interfered with in photographing.

[0003] Patent Document 1 describes a photography tampering detection device that detects that photography of a platform camera installed in an amusement park is being thwarted based on image information captured by the platform camera. The photography tampering detection device includes a photography tampering determination means that determines whether photography of the platform camera is being thwarted based on image information indicating information that quantifies the amount of light incident on the platform camera. The photography tampering determination means determines a first state indicating that photography of the platform camera may be thwarted when the numerical information indicated in the image information is within a specific threshold range, and determines a second state in which photography tampering is more likely to occur than in the first state when the first state continues for a predetermined period of time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-223135 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional technology described above, the amount of light entering the shooting lens of the imaging device varies depending on the environment in which the imaging device is placed, and therefore there is a problem in that the imaging device may be erroneously determined to be experiencing shooting interference even when shooting is not being prevented.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a technique for improving the accuracy of determining whether or not an imaging device is being interfered with in imaging. [Means for solving the problem]

[0007] The photography tampering detection device of the present disclosure includes an estimated information acquisition unit that acquires multiple pieces of interference estimation information indicating an estimation result of whether or not a corresponding imaging device among multiple imaging devices classified into multiple groups according to the illumination environment in which the imaging device is installed is being interfered with in photography, and an interference identification unit that identifies whether or not a first imaging device is being interfered with in photography, based on the interference estimation information corresponding to a first imaging device among the multiple imaging devices and the interference estimation information corresponding to a second imaging device belonging to the same group as the first imaging device among the multiple imaging devices, among the multiple interference estimation information acquired by the estimated information acquisition unit. Effect of the Invention

[0008] According to the present disclosure, it is possible to improve the accuracy of determining whether or not imaging is being obstructed by an imaging device. [Brief description of the drawings]

[0009] [Figure 1] 1 is a top view of the interior of a railway vehicle 10 in which a plurality of imaging devices of a photography tampering detection system according to a first embodiment are installed. [Diagram 2] 1 is a configuration diagram showing an example of a system configuration of a photography tampering detection system according to a first embodiment. [Diagram 3] 3A, 3B, 3C, and 3D are cross-sectional views showing examples of cross-sections at dotted lines Ya1-Ya2, Yb1-Yb2, Yc1-Yc2, and Yd1-Yd2, respectively, when looking at the inside of the railway vehicle 10 from the direction of arrow X in FIG. 1. [Figure 4] FIG. 2 is a diagram showing an example of the range in which each of a plurality of imaging devices captures an image of the interior of a railway vehicle. [Diagram 5]5A, 5B, 5C, and 5D are diagrams showing examples of image information obtained by capturing images using a plurality of imaging devices. [Figure 6] 2 is a block diagram showing an example of a configuration of a main part of a photography tampering detection device in the photography tampering detection system according to the first embodiment. FIG. [Figure 7] Fig. 7A is a diagram showing an example of a case where the interference identification unit identifies that a certain imaging device is not being interfered with in its photography, and Fig. 7B is a diagram showing an example of a case where the interference identification unit identifies that a certain imaging device is being interfered with in its photography. [Figure 8] 2 is a diagram showing an example of the presence or absence of photography sabotage estimated for each of the four imaging devices shown in FIG. 1 and the presence or absence of photography sabotage identified by an interference identifying unit. FIG. [Figure 9] 9A and 9B are diagrams illustrating an example of a hardware configuration of a photography tampering detection device in the photography tampering detection system according to the first embodiment. [Figure 10] 4 is a flowchart illustrating an example of a process performed by a photography tampering detection device in the photography tampering detection system according to the first embodiment. [Figure 11] FIG. 11 is a block diagram showing an example of a configuration of a main part of a photography tampering detection device in a photography tampering detection system according to a second embodiment. [Figure 12] 13 is a flowchart illustrating an example of a process performed by a photography tampering detection device in the photography tampering detection system according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In order to explain the present disclosure in more detail, embodiments for carrying out the present disclosure will be described below with reference to the accompanying drawings. Embodiment 1 Fig. 1 is a top view of the inside of a railway vehicle 10 in which a plurality of imaging devices of a photography tampering detection system 1 according to embodiment 1 are installed. In embodiment 1, an example in which a plurality of imaging devices of a photography tampering detection system 1 according to embodiment 1 are installed inside a railway vehicle 10 as shown in Fig. 1 will be described, but the plurality of imaging devices of the photography tampering detection system 1 may be installed inside a vehicle other than a railway vehicle, inside a building, or the like, and is not limited to this example.

[0011] 2 is a configuration diagram showing an example of the system configuration of the photography tampering detection system 1 according to embodiment 1. The photography tampering detection system 1 includes, as essential parts, a railway vehicle 10, a plurality of imaging devices 11-1, 11-2, ..., 11-N (N is a natural number), a communication network 12, an image recording device 13, a display device 14, and a photography tampering detection device 100. Note that the photography tampering detection system 1 does not necessarily have to include the image recording device 13.

[0012] Each of the multiple imaging devices 11-1, 11-2, ..., 11-N is, for example, a digital still camera or a digital video camera, and can output image information obtained by shooting to the outside. Each of the multiple imaging devices 11-1, 11-2, ..., 11-N is installed inside the railway vehicle 10, and shoots the interior of the railway vehicle 10. Each of the multiple imaging devices 11-1, 11-2, ..., 11-N outputs image information obtained by shooting to the outside via a communication network 12, such as a LAN (Local Area Network) or a wireless LAN.

[0013] 1 and 2 show only four imaging devices 11-1, 11-2, 11-3, and 11-4 out of the multiple imaging devices 11-1, 11-2, ..., 11-N installed on the railway vehicle 10, and the configuration of the imaging devices of the photography tampering detection system 1 according to the first embodiment will be described using the four imaging devices 11-1, 11-2, 11-3, and 11-4. The number of imaging devices provided in the photography tampering detection system 1 may be more than one, and may be three or less or five or more.

[0014] 3A, 3B, 3C, and 3D are cross-sectional views showing examples of cross-sections at dotted lines Ya1-Ya2, Yb1-Yb2, Yc1-Yc2, and Yd1-Yd2, respectively, when looking at the inside of the railway vehicle 10 from the direction of arrow X in FIG. 1.

[0015] FIG. 4 is a diagram showing an example of the range in which each of the imaging devices 11-1, 11-2, 11-3, and 11-4 captures an image of the interior of the railcar 10. As shown in FIG. 5A, 5B, 5C, and 5D are diagrams showing examples of image information obtained by imaging using the plurality of imaging devices 11-1, 11-2, 11-3, and 11-4, respectively.

[0016] As can be seen from Fig. 3 to Fig. 5, the multiple imaging devices 11-1, 11-2, 11-3, and 11-4 are installed above the doors through which passengers enter and exit when getting on and off, so that the multiple imaging devices 11-1, 11-2, 11-3, and 11-4 are arranged in a staggered arrangement. This allows the multiple imaging devices 11-1, 11-2, 11-3, and 11-4 to capture the entire interior of the railway vehicle 10. The multiple imaging devices 11-1, 11-2, 11-3, and 11-4 only need to be able to capture the interior of the railway vehicle 10, and may be installed at positions other than the above the doors through which passengers enter and exit when getting on and off. The multiple imaging devices 11-1, 11-2, 11-3, and 11-4 may be arranged in an arrangement other than the staggered arrangement.

[0017] The image recording device 13 acquires each piece of image information output by the multiple imaging devices 11-1, 11-2, ..., 11-N, associates each piece of acquired image information with identification information for identifying the imaging devices 11-1, 11-2, ..., 11-N and acquisition time information indicating the time when the image was acquired, and records the information in a non-volatile storage medium or the like built into the image recording device 13. More specifically, for example, the image recording device 13 acquires each piece of image information output by the multiple imaging devices 11-1, 11-2, ..., 11-N via the communication network 12.

[0018] As long as image recording device 13 can acquire each piece of image information output by multiple imaging devices 11-1, 11-2, ..., 11-N via communication network 12, the location where image recording device 13 is installed is not limited to inside railway vehicle 10, and image recording device 13 may be installed, for example, at a location away from railway vehicle 10. In the first embodiment, image recording device 13 will be described as being installed inside railway vehicle 10.

[0019] As described later, the photography tampering detection device 100 specifies whether or not each of the multiple imaging devices 11-1, 11-2, ..., 11-N is being tampered with in photography based on multiple pieces of tampering estimation information each indicating an estimation result of whether or not a corresponding imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-N is being tampered with in photography, and outputs an identification display signal for identifying the imaging device specified as being tampered with in photography. Details will be described later.

[0020] The display device 14 displays the identification display signal output by the photography tampering detection device 100. The display device 14 is composed of, for example, a plurality of light-emitting elements corresponding to the plurality of imaging devices 11-1, 11-2, ..., 11-N, respectively. The light-emitting elements are, for example, light-emitting diodes or lamps. When the display device 14 is composed of a plurality of light-emitting elements, the photography tampering detection device 100 controls the light emission of each light-emitting element by outputting an identification display signal.

[0021] The display device 14 is not limited to a display device configured with a plurality of light emitters. For example, the display device 14 may be a display such as a liquid crystal display. When the display device 14 is a display, the photography tampering detection device 100 outputs an image for identifying the imaging device identified as being subject to photography tampering as an identification display signal to the display, and performs display control of the display.

[0022] Alternatively, for example, the display device 14 may be an audio output device such as a speaker or a buzzer. When the display device 14 is an audio output device, the photography tampering detection device 100 performs notification control for notifying by audio by outputting an identification display signal to the audio output device.

[0023] Alternatively, for example, the display device 14 may display an image signal output by an external device such as a computer (not shown). When the display device 14 displays an image signal output by an external device, the photography tampering detection device 100 outputs an identification signal for identifying an imaging device identified as being subject to photography tampering to the external device via the communication network 12, and the external device generates an image signal based on the identification signal acquired from the photography tampering detection device 100 and outputs the image signal to the display device 14.

[0024] 2, in the first embodiment, the display device 14 is configured with a plurality of light emitters 14-1, 14-2, 14-3, and 14-4 corresponding to the plurality of imaging devices 11-1, 11-2, 11-3, and 11-4, respectively, arranged in a housing of the photography tampering detection device 100. The display device 14 controls the light emission of each of the plurality of light emitters 14-1, 14-2, 14-3, and 14-4 by the photography tampering detection device 100 outputting an identification display signal.

[0025] FIG. 6 is a block diagram showing an example of a configuration of a main part of the photography tampering detection device 100 in the photography tampering detection system 1 according to the first embodiment. The photography tampering detection device 100 includes an estimated information acquisition unit 110 , an image acquisition unit 120 , an image brightness acquisition unit 130 , a reference brightness acquisition unit 140 , a tampering estimation unit 150 , a tampering identification unit 160 , and an output control unit 170 .

[0026] The image acquiring unit 120 acquires each piece of image information output by the multiple imaging devices 11-1, 11-2, ..., 11-N via the communication network 12. The image acquiring unit 120 may acquire each piece of image information output by the multiple imaging devices 11-1, 11-2, ..., 11-N and recorded by the image recording device 13 via the communication network 12 from the image recording device 13.

[0027] The image brightness acquisition section 130 divides each image captured by the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple partial images, and acquires image brightness information indicating the brightness of each partial image in each of the images. More specifically, in the first embodiment, the image brightness acquisition section 130 divides an image indicated by each piece of image information acquired by the image acquisition section 120 into multiple partial images, and acquires image brightness information indicating the brightness of each partial image in the image indicated by each piece of image information.

[0028] More specifically, the image luminance acquisition unit 130 divides each image captured by the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple partial images, and calculates the average luminance value of each partial image in each image to acquire image luminance information indicating the average luminance value of each partial image in each image. Note that the "average luminance value of each partial image" here means the average luminance value of each partial image.

[0029] For example, the image brightness acquisition unit 130 may acquire image brightness information indicating the brightness of each partial image in each image captured by multiple imaging devices 11-1, 11-2, ..., 11-N from the imaging devices 11-1, 11-2, ..., 11-N or the image recording device 13 via the communication network 12.

[0030] For example, the image brightness acquisition unit 130 divides each image captured by the multiple imaging devices 11-1, 11-2,...,11-N into two halves, an upper half and a lower half, and calculates the average brightness of the upper half of each image and the average brightness of the lower half of each image. Note that the image brightness acquisition unit 130 may divide each image captured by the multiple imaging devices 11-1, 11-2,...,11-N into three or more parts, or may divide the image so that each partial image has a different size.

[0031] The reason why the image brightness acquisition unit 130 calculates the brightness for each partial image is that when the multiple image capture devices 11-1, ..., 11-N are classified in advance into multiple groups as described below, in a group with low brightness, even if an image capture device is tampered with, the change in brightness is small, so that the tampering may not be detected.

[0032] By having the image brightness acquisition unit 130 calculate the brightness for each partial image as described above, it is possible to reduce the possibility of not being able to detect photography interference, which will be described later, in cases where strong light falls on part of the image, such as when an emergency light is turned on in front of the imaging device.

[0033] The reference luminance acquisition section 140 acquires reference luminance information indicating predetermined reference luminances corresponding to the plurality of image capture devices 11-1, 11-2, . . . , 11-N, respectively. For example, the reference luminance acquisition section 140 acquires reference luminance information from the multiple image capture devices 11-1, 11-2, . . . , 11-N or the image recording device 13 via the communication network 12. The reference brightness acquisition unit 140 may acquire the reference brightness information by reading the reference brightness information from a storage device (not shown) provided inside or outside the housing of the photography tampering detection device 100 .

[0034] The interference estimation unit 150 compares the brightness of each partial image indicated by the image brightness information acquired by the image brightness acquisition unit 130 with the reference brightness indicated by the reference brightness information acquired by the reference brightness acquisition unit 140 for each imaging device. The interference estimation unit 150 generates a plurality of interference estimation information each indicating an estimation result of whether or not the corresponding imaging device among the plurality of imaging devices 11-1, 11-2, . . . , 11-N is being interfered with in the imaging device that is estimated to be interfered with in the imaging device by the comparison. More specifically, in the first embodiment, the interference estimation unit 150 generates interference estimation period information indicating the interference estimation period for an imaging device among the plurality of imaging devices 11-1, 11-2, . . . , 11-N that is estimated to be interfered with in the imaging device by measuring the interference estimation period during which the imaging device is continuously estimated to be interfered with in the imaging device. The interference estimation unit 150 outputs the generated interference estimation information and interference estimation period information to the estimation information acquisition unit 110.

[0035] For example, when estimating the presence or absence of shooting interference, the interference estimation unit 150 may use the average brightness of all images indicated by the image brightness information acquired by the image brightness acquisition unit 130, instead of the reference brightness indicated by the reference brightness information acquired by the reference brightness acquisition unit 140.

[0036] For example, when the lower half of the optical system such as a lens in any one of the multiple imaging devices 11-1, 11-2, ..., 11-N is covered with a light-shielding cloth or the like, the luminance of each of the two partial images obtained by dividing an image captured by the imaging device into upper and lower halves is such that the luminance of the upper half partial image is higher than the reference luminance of the imaging device, and the luminance of the lower half partial image is lower. Therefore, when the interference estimation unit 150 compares the luminance of each of the two partial images obtained by dividing an image into upper and lower halves with the reference luminance of the imaging device that captured the image, and determines that the luminance of the upper half partial image is higher than the reference luminance and the luminance of the lower half partial image is lower than the reference luminance, it generates interference estimation information indicating an estimation result that the imaging device is being interfered with in the imaging process, or interference estimation information indicating an estimation result that the lower half of the optical system of the imaging device is being interfered with in the imaging process.

[0037] Or, for example, the interference estimation unit 150 compares the luminance of each of two partial images obtained by dividing an image into upper and lower halves with the reference luminance of the imaging device that captured the image, and if it determines that the luminance of the upper half of the partial image is a value within a predetermined range centered on the reference luminance and the luminance of the lower half of the partial image is a value outside a predetermined range centered on the reference luminance, it generates interference estimation information indicating an estimation result that the imaging device is being interfered with in imaging, or interference estimation information indicating an estimation result that the lower half of the optical system of the imaging device is being interfered with in imaging.

[0038] That is, the interference estimation unit 150 may generate interference estimation information indicating an estimation result as to whether or not the imaging device is being partially interfered with in its photographing operation by comparing the luminance of each partial image with a reference luminance.

[0039] Alternatively, for example, when the optical system such as a lens in any one of the multiple imaging devices 11-1, 11-2, ..., 11-N is entirely covered with a light-shielding cloth or the like, the luminance of each of the multiple partial images obtained by dividing an image captured by the imaging device is all lower than the reference luminance of the imaging device. Therefore, for example, when the interference estimation unit 150 compares the luminance of each of the multiple partial images obtained by dividing an image with the reference luminance of the imaging device that captured the image and determines that each of the luminances is all lower than the reference luminance, it generates interference estimation information indicating an estimation result that the imaging device is being interfered with, or interference estimation information indicating an estimation result that the entire optical system of the imaging device is being interfered with.

[0040] Alternatively, for example, when the optical system of any of the imaging devices 11-1, 11-2, . . . , 11-N is irradiated with strong white light from the outside, the luminances of the partial images obtained by dividing an image captured by the imaging device are all higher than the reference luminance of the imaging device. Therefore, for example, when the interference estimation unit 150 compares the luminances of the partial images obtained by dividing an image with the reference luminance of the imaging device that captured the image, and determines that the luminances are all higher than the reference luminance, it generates interference estimation information indicating an estimation result that the imaging device is being interfered with, or interference estimation information indicating an estimation result that the entire optical system of the imaging device is being interfered with.

[0041] Alternatively, for example, the interference estimation unit 150 compares the luminance of each of a plurality of partial images obtained by dividing an image with the reference luminance of the imaging device that captured the image, and when it is determined that the luminances are all values ​​within a predetermined range centered on the reference luminance, it generates interference estimation information indicating an estimation result that the imaging device is not being interfered with in the imaging process. On the other hand, when it is determined that the luminances are all values ​​outside a predetermined range centered on the reference luminance, it generates interference estimation information indicating an estimation result that the imaging device is being interfered with in the imaging process, or interference estimation information indicating an estimation result that the entire optical system of the imaging device is being interfered with in the imaging process.

[0042] That is, the interference estimation unit 150 may generate interference estimation information indicating an estimation result as to whether or not the imaging device is being interfered with in its entirety by comparing the luminance of each partial image with a reference luminance.

[0043] In the first embodiment, as an example, the interference estimation unit 150 will be described as comparing the luminance of each of two partial images obtained by dividing an image into upper and lower halves with the reference luminance of the imaging device that captured the image, and if it determines that the luminance of the upper half of the partial image is higher than the reference luminance and the luminance of the lower half of the partial image is lower than the reference luminance, it will generate interference estimation information indicating the estimation result that the lower half of the optical system of the imaging device is being interfered with.

[0044] For example, even if the already installed imaging devices 11-1, 11-2, . . . , 11-N and the image recording device 13 cannot generate interference estimation information, the above-mentioned photography interference detection device 100 can generate interference estimation information by including the image acquisition unit 120, the image brightness acquisition unit 130, the reference brightness acquisition unit 140, and the interference estimation unit 150. Thus, a photography interference detection system 1 using interference estimation information can be constructed.

[0045] The estimated information acquisition unit 110 acquires a plurality of pieces of interference estimated information each indicating an estimation result as to whether or not a corresponding imaging device among the plurality of imaging devices 11-1, 11-2, . . . , 11-N is being interfered with in shooting. More specifically, in the first embodiment, the estimated information acquisition unit 110 acquires a plurality of pieces of interference estimated information generated by the interference estimation unit 150.

[0046] More specifically, in the first embodiment, the estimated information acquisition unit 110 further acquires, for an imaging device estimated to be obstructed from among the multiple imaging devices 11-1, 11-2, . . . , 11-N, interference estimated period information indicating an interference estimated period during which the imaging device is continuously estimated to be obstructed from being obstructed from being photographed. More specifically, in the first embodiment, the estimated information acquisition unit 110 further acquires interference estimated period information generated by the interference estimation unit 150. Alternatively, the estimated information acquisition unit 110 may acquire interference estimated period information by measuring an interference estimated period based on the acquired multiple pieces of interference estimated information. The estimated information acquisition unit 110 outputs the acquired multiple pieces of interference estimated information and interference estimated period information to the interference identification unit 160.

[0047] The estimated information acquisition unit 110 may acquire the interference estimated information generated by the multiple imaging devices 11-1, 11-2,...,11-N from the multiple imaging devices 11-1, 11-2,...,11-N. In this case, the multiple imaging devices 11-1, 11-2,...,11-N estimate whether or not the multiple imaging devices 11-1, 11-2,...,11-N are being interfered with in their imaging by comparing the luminance of multiple partial images obtained by dividing each captured image with a predetermined reference luminance corresponding to each imaging device 11-1, 11-2,...,11-N. Then, the multiple imaging devices 11-1, 11-2,...,11-N each generate interference estimated information indicating whether or not the imaging device is being interfered with in their imaging based on the estimation result. Then, each of the multiple imaging devices 11-1, 11-2, . . . , 11-N outputs the generated sabotage estimation information to the photography sabotage detection device 100 via the communication network 12. In this way, the processing load of the photography tampering detection device 100 can be reduced by each of the multiple imaging devices 11-1, 11-2, . . . , 11-N generating tampering estimation information.

[0048] Alternatively, the estimated information acquisition unit 110 may acquire the interference estimated information generated by the image recording device 13 from the image recording device 13. In this case, the image recording device 13 divides an image indicated by each piece of image information acquired from the multiple imaging devices 11-1, 11-2, . . . , 11-N into multiple partial images, and calculates the luminance of each partial image in the image indicated by each piece of image information. Then, the image recording device 13 generates interference estimated information by comparing the calculated luminance of each partial image with a predetermined reference luminance corresponding to each of the multiple imaging devices 11-1, 11-2, . . . , 11-N. Then, the image recording device 13 outputs the generated interference estimated information to the photography interference detection device 100 via the communication network 12.

[0049] In this way, the image recording device 13 generates the interference estimation information, thereby reducing the processing load of the photography interference detection device 100. Even if each of the multiple imaging devices 11-1, 11-2, ..., 11-N already installed cannot generate interference estimation information, the image recording device 13 generates the interference estimation information, thereby making it possible to construct the photography interference detection system 1 using the interference estimation information.

[0050] In addition, when the estimated information acquisition unit 110 acquires tampering estimated information generated by multiple imaging devices 11-1, 11-2, ..., 11-N or the image recording device 13, the image acquisition unit 120, the image brightness acquisition unit 130, the reference brightness acquisition unit 140, and the tampering estimation unit 150 are not essential components in the photography tampering detection device 100.

[0051] The interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2,...,11-N into multiple sets, and identifies whether or not the first imaging device is being interfered with in shooting based on interference estimation information corresponding to the first imaging device among the multiple interference estimation information acquired by the estimation information acquisition unit 110, and interference estimation information corresponding to a second imaging device among the multiple imaging devices 11-1, 11-2,...,11-N that belongs to the same set as the first imaging device. Note that the interference identification unit 160 may classify the multiple imaging devices 11-1, 11-2,...,11-N into a single set.

[0052] In more detail, in embodiment 1, if all of the interference estimation information acquired by the estimation information acquisition unit 110 corresponding to each imaging device of the set to which the first imaging device and the second imaging device belong indicates an estimation result that the corresponding imaging device is being interfered with in shooting, the interference identification unit 160 identifies that none of the imaging devices are being interfered with in shooting.

[0053] More specifically, for example, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a single group, and if it is estimated that the imaging device 11-1 is experiencing interference with photography and if it is estimated that all of the multiple imaging devices 11-2, ..., 11-N are experiencing interference with photography, it identifies the imaging device 11-1 as not experiencing interference with photography.

[0054] This is because, for example, when a railway vehicle 10 equipped with multiple imaging devices 11-1, ..., 11-N enters a depot with all of the interior lights on, a situation may occur in which the upper half of the images captured by each imaging device appears bright due to the interior lights, and the lower half of the images appears dark.

[0055] Or, for example, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set and a second set, and when it is estimated that all of the multiple imaging devices 11-1 to 11-M (1≦M≦N-1) belonging to the first set are experiencing interference with imaging, it identifies the imaging device 11-1 as not experiencing interference with imaging.

[0056] This is because, for example, in a railway vehicle 10 equipped with a plurality of imaging devices 11-1,...,11-N, when the railway vehicle 10 is stored in a depot with all interior lights in front of the plurality of imaging devices 11-1 to 11-M (1≦M≦N-1) turned on and all interior lights in front of the other imaging devices turned off, the upper half of each image captured by the plurality of imaging devices 11-1 to 11-M appears bright due to the interior lights, the lower half of the image appears dark, and the images captured by the other imaging devices appear dark. Alternatively, for example, when a railway vehicle 10 equipped with a plurality of imaging devices 11-1,...,11-N is stored in a depot with all interior lights turned off, the illuminance inside the entire railway vehicle is assumed to be insufficient.

[0057] Regarding the classification, for example, in the first embodiment, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2,...,11-N into a first set including multiple imaging devices 11-1, 11-2,...,11-M (1≦M≦N-1) and a second set including multiple imaging devices 11-K,...,11-N (K=M+1). In this case, the interference identification unit 160 identifies whether or not the imaging device 11-1 is being interfered with in its shooting based on each of the interference estimation information corresponding to the multiple imaging devices 11-1, 11-2,...,11-M belonging to the first set among the multiple pieces of interference estimation information, and identifies whether or not the imaging device 11-K is being interfered with in its shooting based on each of the interference estimation information corresponding to the imaging devices 11-K,...,11-N belonging to the second set among the multiple pieces of interference estimation information.

[0058] For example, the interference identification unit 160 may classify the multiple imaging devices 11-1, 11-2, . . . , 11-N into multiple sets based on the current time. In this case, for example, when the current time corresponds to a daytime time zone, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, . . . , 11-N into multiple sets, and when the current time corresponds to a nighttime time zone, the interference identification unit 160 does not classify the multiple imaging devices 11-1, 11-2, . . . , 11-N into a single set. The daytime time zone here is, for example, the time zone from sunrise to sunset. The nighttime time zone here is, for example, the time zone from sunset to sunrise.

[0059] Alternatively, for example, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple sets based on the current position of the vehicle. In this case, for example, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple sets based on position influence information in which a position on the route along which the vehicle travels is associated with sunlight influence information indicating whether or not the multiple imaging devices 11-1, 11-2, ..., 11-N are influenced by sunlight when capturing an image at that position.

[0060] Alternatively, for example, the interference identification unit 160 may classify the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple sets based on the multiple interference estimation information acquired by the estimated information acquisition unit 110. In this case, for example, the interference identification unit 160 classifies the imaging devices corresponding to interference estimation information indicating an estimation result that the imaging device is totally interfered with in the imaging, among the multiple interference estimation information acquired by the estimated information acquisition unit 110, into a first set. Also, for example, the interference identification unit 160 classifies the imaging devices corresponding to interference estimation information indicating an estimation result that the imaging device is partially interfered with in the imaging, among the multiple interference estimation information acquired by the estimated information acquisition unit 110, into a second set.

[0061] More specifically, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N as follows, based on any of the above information or a predetermined classification criterion. For example, when some of the interior lights are turned on, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including imaging devices installed in front of the turned-on interior lights, and a second set including imaging devices not installed in front of the turned-on interior lights.

[0062] Or, for example, when external light is incident on the vehicle, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including imaging devices that are easily affected by external light, and a second set including imaging devices that are not easily affected by external light.

[0063] Or, for example, when imaging devices are installed in the vehicle passenger compartment and outside the vehicle passenger compartment (such as a deck or a coupling section), the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including imaging devices installed in the vehicle passenger compartment that capture areas where the brightness of the interior lighting is relatively high, and a second set including imaging devices installed outside the vehicle passenger compartment that capture areas where the brightness of the interior lighting is relatively low.

[0064] Or, for example, in the case of installing imaging devices that capture images inside and outside the vehicle (such as pantographs), the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including imaging devices that capture images inside the vehicle and are less susceptible to the influence of external light, and a second set including imaging devices that capture images outside the vehicle and are more susceptible to the influence of external light.

[0065] Or, for example, when the installation heights of multiple imaging devices are different, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into a first set including imaging devices installed at heights that are susceptible to interference with photography, and a second set of imaging devices installed at heights that are less susceptible to interference with photography.

[0066] In further detail, in the first embodiment, the interference identification unit 160 identifies whether or not the first imaging device is being interfered with in its photographing based further on the interference estimated period indicated by the interference estimated period information further acquired by the estimated information acquisition unit 110.

[0067] For example, when it is estimated that a first imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M included in the first set is being disrupted from photographing, the interference identification unit 160 identifies whether or not the first imaging device is being disrupted from photographing, based on interference estimation information indicating whether or not a second imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M included in the first set is being disrupted from photographing, and the length of the interference estimation period during which it is continuously estimated that the first imaging device is being disrupted from photographing.

[0068] At the same time, for example, when it is estimated that a third imaging device among the multiple imaging devices 11-K, ..., 11-N included in the second set is being disrupted from photographing, the interference identification unit 160 identifies whether or not a fourth imaging device among the multiple imaging devices 11-K, ..., 11-N included in the second set is being disrupted from photographing, based on interference estimation information indicating whether or not photographing is being disrupted from the fourth imaging device among the multiple imaging devices 11-K, ..., 11-N included in the second set, and the length of the interference estimation period during which it is continuously estimated that the third imaging device is being disrupted from photographing.

[0069] More specifically, for example, if there are four imaging devices 11-1, ..., 11-4 and the interference identification unit 160 defines the multiple imaging devices 11-1 and 11-2 as a first set and the multiple imaging devices 11-3 and 11-4 as a second set, when it is estimated that only the lower half of the image of imaging device 11-1 is being interfered with, and when it is estimated that only the lower half of the image of imaging device 11-2 is being interfered with, the interference identification unit 160 will identify imaging device 11-1 as not being interfered with.

[0070] At the same time, for example, if it is estimated that the entire image of imaging device 11-3 is being interfered with, and also that the entire image of imaging device 11-4 is being interfered with, the interference identification unit 160 identifies imaging device 11-3 as not being interfered with.

[0071] This is because, for example, when a railway vehicle 10 having multiple imaging devices 11-1, ..., 11-4 installed is entered into a depot with all interior lights in front of imaging device 11-1 and imaging device 11-2 turned on and all interior lights in front of the other imaging devices turned off, it is anticipated that the upper half of the images captured by imaging device 11-1 and imaging device 11-2 will appear bright due to the interior lights and the lower half of the images will appear dark, and the images captured by the other imaging devices will appear dark.

[0072] Alternatively, for example, when the estimated information acquisition unit 110 does not further acquire the interference estimated period information, the following configuration may be adopted. That is, when it is estimated that the imaging device 11-1 is disturbed in shooting and it is estimated that none of the imaging devices 11-2, . . . , 11-N is disturbed in shooting, the interference identification unit 160 may measure the length of the interference estimated period during which the imaging device 11-1 is continuously estimated to be disturbed in shooting, based on the interference estimated information corresponding to the imaging device 11-1. In this case, the interference identification unit 160 measures the interference estimated period from when it is first determined that the imaging device 11-1 is disturbed in shooting to when it is determined that the imaging device 11-1 is continuously disturbed in shooting, using, for example, a timer (not shown).

[0073] For example, when the length of the estimated interference period during which it is continuously estimated that the imaging device 11-1 is being interfered with in shooting is shorter than a predetermined period, the interference identification unit 160 identifies that the imaging device 11-1 is not being interfered with in shooting.

[0074] This is because it is expected that the optical system of the imaging device 11-1 may be temporarily covered if, for example, the optical system is inadvertently covered by luggage of a passenger or the like boarding the railway vehicle 10.

[0075] The interference identifying unit 160 identifies the imaging device 11-1 as being subjected to interference with photography when the length of the estimated interference period during which it has been continuously estimated that the imaging device 11-1 is being interfered with is equal to or longer than a predetermined period. This is because it is assumed that the optical system of the imaging device 11-1 is continuously covered.

[0076] For example, the interference identification unit 160 may classify the multiple imaging devices 11-1, ..., 11-N into multiple groups in advance, and measure the length of the estimated interference period during which it is continuously estimated that the imaging device is being interfered with in each group.

[0077] More specifically, when it is estimated that imaging device 11-1 of multiple imaging devices 11-1, 11-2, ..., 11-M (1≦M≦N-1) is being interfered with in photography, the interference identification unit 160 measures, for example, using a timer not shown, the estimated interference period from when it is first determined that imaging device 11-1 is being interfered with in photography to when it is determined that imaging device 11-1 is continuously being interfered with in photography, as the length of the estimated interference period during which imaging device 11-1 is being interfered with in photography. Furthermore, when it is estimated that the imaging device 11-K among the multiple imaging devices 11-K, ..., 11-N (K = M + 1) is being interfered with in photography, the interference identification unit 160 measures, for example, using a timer not shown, the estimated interference period from when it is first determined that the imaging device 11-K is being interfered with in photography to when it is determined that the imaging device 11-K is being continuously interfered with in photography, as the length of the estimated interference period during which the imaging device 11-K is being continuously interfered with in photography.

[0078] The interference identifying unit 160 identifies that the imaging device 11-1 is not being interfered with in the shooting of the imaging device 11-1 when the length of the interference estimated period during which it has been continuously estimated that the imaging device 11-1 is being interfered with in the shooting of the imaging device 11-1 is shorter than the length of a predetermined period. Also, the interference identifying unit 160 identifies that the imaging device 11-K is not being interfered with in the shooting of the imaging device 11-K when the length of the interference estimated period during which it has been continuously estimated that the imaging device 11-K is being interfered with in the shooting of the imaging device 11-K is shorter than the length of a predetermined period.

[0079] This is because it is expected that the optical system of imaging device 11-1 will be temporarily covered, for example, when the optical systems of imaging devices 11-1 and 11-K are covered by work by a worker or the like who is on board the railway vehicle 10 to inspect the vehicle.

[0080] The interference identifying unit 160 identifies the imaging device 11-1 as being interfered with in the shooting of the imaging device 11-1 when the length of the interference estimated period during which it has been continuously estimated that the imaging device 11-1 is being interfered with in the shooting of the imaging device 11-1 is longer than the length of a predetermined period. Also, the interference identifying unit 160 identifies the imaging device 11-K as being interfered with in the shooting of the imaging device 11-K when the length of the interference estimated period during which it has been continuously estimated that the imaging device 11-K is being interfered with in the shooting of the imaging device 11-K is longer than the length of a predetermined period. This is because it is assumed that the optical systems of the image capture devices 11-1 and 11-K are continuously covered.

[0081] The length of the interference estimated period that is determined when the interference identifying unit 160 identifies whether or not the imaging device 11-1 is being interfered with in shooting will be described below with reference to FIG. FIG. 7A is a diagram showing an example of a case where the interference identifying unit 160 identifies that a certain imaging device is not being interfered with in photography. FIG. 7B is a diagram showing an example of a case where the interference identifying unit 160 identifies that a certain imaging device is being interfered with in its photographing. 7A and 7B, the horizontal axis indicates time, and the vertical axis indicates luminance. The solid broken line indicates the luminance in an image captured by a certain imaging device. The dashed straight line indicates the reference luminance of the imaging device.

[0082] As shown in FIG. 7A, when the brightness of an image captured by a certain imaging device is lower than the reference brightness of the imaging device, but is not continuously lower for a predetermined period of time, the interference identification unit 160 identifies that the imaging device is not being interfered with.

[0083] Furthermore, as shown in FIG. 7B, when the luminance of an image captured by a certain imaging device is continuously lower than the reference luminance of the imaging device for a predetermined period of time, the interference identification unit 160 identifies the imaging device as being subject to interference with imaging.

[0084] A method in which the interference identifying unit 160 identifies the presence or absence of imaging interference based on the interference estimated information acquired by the estimated information acquiring unit 110 will be described below with reference to FIG. FIG. 8 is a diagram showing an example of the presence or absence of photography interference estimated for each of the four imaging devices 11-1, 11-2, 11-3, and 11-4 shown in FIG.

[0085] At the time indicated by (1) in FIG. 8, it is estimated that none of the four imaging devices 11-1, 11-2, 11-3, and 11-4 is interfering with imaging. FIG. 8 shows an example in which, starting from the point indicated by (1), the estimated information acquisition unit 110 acquires each piece of interference estimated information corresponding to four imaging devices 11-1, 11-2, 11-3, and 11-4 every 15 minutes, and the interference identification unit 160 identifies the presence or absence of interference with filming based on each piece of interference estimated information acquired by the estimated information acquisition unit 110.

[0086] At the points in time indicated by (2) to (8) in Figure 8, of the four imaging devices 11-1, 11-2, 11-3, and 11-4, it is estimated that imaging device 11-1 is experiencing imaging interference, and it is estimated that imaging devices other than imaging device 11-1 are not experiencing imaging interference.

[0087] FIG. 8 shows an example in which the interference identification unit 160 identifies the imaging device 11-1 as being subject to interference with imaging when it is estimated that the imaging device 11-1 has been subjected to interference with imaging for a period exceeding one hour, which is a predetermined period.

[0088] When the interference identification unit 160 identifies that the first imaging device is being interfered with in its shooting, the output control unit 170 outputs an identification display signal for identifying the first imaging device identified as being interfered with in its shooting.

[0089] More specifically, the output control unit 170 outputs an identification display signal for identifying an imaging device that has been identified as being subject to imaging interference among the imaging devices 11-1, 11-2, ..., 11-N by the interference identification unit 160. More specifically, for example, the output control unit 170 outputs the identification display signal to the display device 14.

[0090] For example, the output control unit 170 may output an identification display signal for identifying an imaging device that the interference identifying unit 160 has identified as not being subjected to imaging interference among the imaging devices 11-1, 11-2, . . . , 11-N.

[0091] For example, when the display device 14 is configured with a plurality of light-emitting elements 14-1, 14-2, 14-3, and 14-4 corresponding to a plurality of imaging devices 11-1, 11-2, 11-3, and 11-4, respectively, as shown in FIG. 2, the output control unit 170 performs output control so as to turn off the light-emitting element corresponding to the imaging device identified as not interfering with photography, and to turn on the light-emitting element corresponding to the imaging device identified as interfering with photography. The display device 14 displays the identification display signal output by the output control unit 170. The details of the identification display signal have been explained above in connection with the display device 14, and therefore will not be explained here.

[0092] 9A and 9B are diagrams showing an example of a hardware configuration of the photography tampering detection device 100 in the photography tampering detection system 1 according to the first embodiment. With reference to this figure, a hardware configuration of a main part of the photography tampering detection device 100 in the photography tampering detection system 1 according to the first embodiment will be described.

[0093] 9A, the photography tampering detection device 100 is configured by a computer, and the computer has a processor 901 and a memory 902. The memory 902 stores programs for causing the computer to function as the estimated information acquisition unit 110, the image acquisition unit 120, the image brightness acquisition unit 130, the reference brightness acquisition unit 140, the interference estimation unit 150, the interference identification unit 160, and the output control unit 170. The processor 901 reads out and executes the programs stored in the memory 902, thereby realizing the functions of the estimated information acquisition unit 110, the image acquisition unit 120, the image brightness acquisition unit 130, the reference brightness acquisition unit 140, the interference estimation unit 150, the interference identification unit 160, and the output control unit 170.

[0094] 9B , the shooting tampering detection device 100 may be configured with a processing circuit 903. In this case, the functions of the estimated information acquisition unit 110, the image acquisition unit 120, the image luminance acquisition unit 130, the reference luminance acquisition unit 140, the tampering estimation unit 150, the tampering identification unit 160, and the output control unit 170 may be realized by the processing circuit 903.

[0095] Furthermore, the photography tampering detection device 100 may be configured with a processor 901, a memory 902, and a processing circuit 903 (not shown). In this case, some of the functions of the estimated information acquisition unit 110, the image acquisition unit 120, the image luminance acquisition unit 130, the reference luminance acquisition unit 140, the tampering estimation unit 150, the tampering identification unit 160, and the output control unit 170 may be realized by the processor 901 and the memory 902, and the remaining functions may be realized by the processing circuit 903.

[0096] The processor 901 may be, for example, a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor, a microcontroller, or a digital signal processor (DSP).

[0097] The memory 902 is, for example, a semiconductor memory or a magnetic disk. More specifically, the memory 902 is, for example, a random access memory (RAM), a read only memory (ROM), a flash memory, an erasable programmable read only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a solid state drive (SSD), a hard disk drive (HDD), or the like.

[0098] The processing circuit 903 is, for example, an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), a system-on-a-chip (SoC), or a system large-scale integration (LSI).

[0099] The operation of the photography tampering detection device 100 in the photography tampering detection system 1 according to the embodiment 1 will be described with reference to Fig. 10. Fig. 10 is a flowchart illustrating an example of the processing of the photography tampering detection device 100 in the photography tampering detection system 1 according to the embodiment 1. Note that the photography tampering detection device 100 repeatedly executes the processing of the flowchart every predetermined time such as every 15 minutes as in the example shown in Fig. 8.

[0100] As shown in FIG. 10, in step ST101, the reference luminance acquisition section 140 acquires reference luminance information indicating predetermined reference luminances corresponding to the plurality of image pickup devices 11-1, 11-2, . . . , 11-N, respectively. Next, in step ST102, the image acquisition section 120 acquires, via the communication network 12, each piece of image information output by the multiple image capture devices 11-1, 11-2, . . . , 11-N.

[0101] Next, in step ST103, the image luminance acquisition unit 130 divides the image indicated by each piece of image information acquired by the image acquisition unit 120 into a plurality of partial images, and acquires image luminance information indicating the luminance of each partial image in the image indicated by each piece of image information. Also, in step ST103, the reference luminance acquisition unit 140 acquires reference luminance information indicating predetermined reference luminances corresponding to the plurality of imaging devices.

[0102] Next, in step ST104, the interference estimation unit 150 generates a plurality of interference estimation information by estimating whether or not each of the plurality of imaging devices 11-1, 11-2, . . . , 11-N is being interfered with in the shooting for each imaging device by comparing the brightness of each partial image indicated by the image brightness information acquired by the image brightness acquisition unit 130 and the reference brightness indicated by the reference brightness information acquired by the reference brightness acquisition unit 140 for each imaging device. In addition, the interference estimation unit 150 generates interference estimation period information indicating the interference estimation period for an imaging device estimated to be interfered with in the shooting among the plurality of imaging devices 11-1, 11-2, . . . , 11-N by measuring the interference estimation period during which the imaging device is continuously estimated to be interfered with in the shooting. The interference estimation unit 150 outputs the generated interference estimation information and interference estimation period information to the estimation information acquisition unit 110.

[0103] Next, in step ST105, the estimated information acquisition unit 110 acquires a plurality of pieces of interference estimated information generated by the interference estimation unit 150. In addition, in step ST105, the estimated information acquisition unit 110 further acquires interference estimated period information generated by the interference estimation unit 150.

[0104] Next, in step ST110, the interference identification unit 160 classifies the multiple imaging devices 11-1, 11-2,...,11-N into a first set and a second set. The first set here is composed of the multiple imaging devices 11-1, 11-2,...,11-M (1 <= M <= N-1). The second set here is composed of the multiple imaging devices 11-K,...,11-N (K=M+1).

[0105] Next, in step ST111, the interference identification unit 160 determines whether or not it is estimated that at least one of the imaging devices 11-1, 11-2, . . . , 11-M is disturbed based on each interference estimation information corresponding to the imaging devices 11-1, 11-2, . . . , 11-M belonging to the first set among the multiple interference estimation information acquired by the estimation information acquisition unit 110. Also, in step ST111, the interference identification unit 160 determines whether or not it is estimated that at least one of the imaging devices 11-K, . . . , 11-N is disturbed based on each interference estimation information corresponding to the imaging devices 11-K, . . . , 11-N belonging to the second set among the multiple interference estimation information acquired by the estimation information acquisition unit 110.

[0106] When the interference identifying unit 160 determines in step ST111 that none of the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set is interfered with in shooting, the interference identifying unit 160 identifies in step ST112 that none of the multiple imaging devices 11-1, 11-2, ..., 11-M is interfered with in shooting. After step ST112, in step ST113, the output control unit 170 outputs an identification display signal for identifying each of the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set that the interference identifying unit 160 has identified as not being interfered with in shooting.

[0107] Furthermore, when the interference identifying unit 160 determines in step ST111 that none of the multiple imaging devices 11-K,...,11-N belonging to the second set is interfered with in shooting, in step ST112, it identifies that none of the multiple imaging devices 11-K,...,11-N is interfered with in shooting. After step ST112, in step ST113, the output control unit 170 outputs an identification display signal for identifying each of the multiple imaging devices 11-K, 11-2,...,11-N belonging to the second set that the interference identifying unit 160 has identified as not being interfered with in shooting.

[0108] After step ST113, the photographing tampering detection device 100 ends the process of the flowchart, and repeats the process of the flowchart every time a predetermined time elapses.

[0109] If, in step ST111, the interference identification unit 160 determines that at least one of the multiple imaging devices 11-1, 11-2, ..., 11-M (1≦M≦N-1) belonging to the first set is estimated to be experiencing interference with shooting, in step ST121, the interference identification unit 160 determines whether or not all of the multiple imaging devices 11-1, 11-2, ..., 11-M are estimated to be experiencing interference with shooting, based on each piece of interference estimation information corresponding to the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set, among the multiple pieces of interference estimation information acquired by the estimated information acquisition unit 110. Furthermore, if, in step ST111, the interference identification unit 160 determines that at least one of the multiple imaging devices 11-K, ..., 11-N (K = M + 1) belonging to the second set is estimated to have been interfered with in the shooting, in step ST121, the interference identification unit 160 determines whether or not all of the multiple imaging devices 11-K, ..., 11-N are estimated to have been interfered with in the shooting, based on each piece of interference estimation information corresponding to the multiple imaging devices 11-K, ..., 11-N belonging to the second set, among the multiple pieces of interference estimation information acquired by the estimated information acquisition unit 110.

[0110] If the interference identification unit 160 determines in step ST121 that all of the imaging devices 11-1, 11-2, . . . , 11-M belonging to the first group are estimated to be subject to imaging interference, the imaging interference detection device 100 executes the process of step ST112. If the interference identification unit 160 determines in step ST121 that all of the imaging devices 11-K, . . . , 11-N belonging to the second group are estimated to be subject to imaging interference, the imaging interference detection device 100 executes the process of step ST112.

[0111] If, in step ST121, the interference identification unit 160 determines that at least one of the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set is estimated to be not experiencing shooting interference, in step ST131, the interference identification unit 160 determines whether or not the estimated interference period indicated by the interference estimation period information further acquired by the estimated information acquisition unit 110 exceeds a predetermined period for the imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set that is estimated to be experiencing shooting interference (the imaging device that the interference identification unit 160 has determined to be estimated to be experiencing shooting interference in step ST111).

[0112] Furthermore, if the interference identification unit 160 determines in step ST121 that at least one of the multiple imaging devices 11-K, ..., 11-N belonging to the second set is estimated to be not being interfered with in shooting, then in step ST131 the interference identification unit 160 determines whether or not the estimated interference period indicated by the interference estimation period information further acquired by the estimated information acquisition unit 110 exceeds a predetermined period for the imaging device among the multiple imaging devices 11-K, ..., 11-N belonging to the second set that is estimated to be interfered with in shooting (the imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be interfered with in shooting).

[0113] With regard to an imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set that is estimated to be subject to shooting interference (an imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be subject to shooting interference), if the interference identification unit 160 determines in step ST131 that the estimated interference period indicated by the estimated interference period information further acquired by the estimated information acquisition unit 110 does not exceed a predetermined period, then in step ST132, it identifies the imaging device (the imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be subject to shooting interference) as not being subject to shooting interference.

[0114] With regard to an imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set that is estimated to be subject to shooting interference (an imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be subject to shooting interference), if the interference identification unit 160 determines in step ST131 that the estimated interference period indicated by the estimated interference period information further acquired by the estimated information acquisition unit 110 exceeds a predetermined period, then in step ST133, the interference identification unit 160 identifies the imaging device (the imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be subject to shooting interference) as being subject to shooting interference.

[0115] Furthermore, with regard to an imaging device among the multiple imaging devices 11-K, ..., 11-N belonging to the second set that is estimated to be subject to shooting interference (an imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be subject to shooting interference), if the interference identification unit 160 determines in step ST131 that the estimated interference period indicated by the estimated interference period information further acquired by the estimated information acquisition unit 110 does not exceed a predetermined period, then in step ST132, the interference identification unit 160 identifies the imaging device (the imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be subject to shooting interference) as not being subject to shooting interference.

[0116] With regard to an imaging device among the multiple imaging devices 11-K, ..., 11-N belonging to the second set that is estimated to be subject to shooting interference (an imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be subject to shooting interference), if the interference identification unit 160 determines in step ST131 that the estimated interference period indicated by the estimated interference period information further acquired by the estimated information acquisition unit 110 exceeds a predetermined period, then in step ST133, the interference identification unit 160 identifies the imaging device (the imaging device that the interference identification unit 160 has determined in step ST111 to be estimated to be subject to shooting interference) as being subject to shooting interference.

[0117] After step ST132 or step ST133, in step ST134, with regard to an imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-M belonging to the first set that is estimated to have not been subjected to shooting interference (an imaging device that the interference identification unit 160 has determined to have not been subjected to shooting interference in step ST111), the interference identification unit 160 identifies that the imaging device is not subjected to shooting interference.

[0118] After step ST132 or step ST133, in step ST134, with regard to an imaging device among the multiple imaging devices 11-K, ..., 11-N belonging to the second set that is estimated to have not been subjected to shooting interference (an imaging device that the interference identification unit 160 has determined to have not been subjected to shooting interference in step ST111), the interference identification unit 160 identifies that the imaging device is not subjected to shooting interference.

[0119] After step ST134, in step ST135, the output control unit 170 outputs an identification display signal for identifying an imaging device that the interference identification unit 160 has identified as having been interfered with in the shooting of an image, or an imaging device that the interference identification unit 160 has identified as not having been interfered with in the shooting of an image.

[0120] After step ST135, the photographing tampering detection device 100 ends the process of the flowchart, and repeats the process of the flowchart every time a predetermined time elapses.

[0121] The process of step ST101 may be configured to be executed only the first time when the photographing tampering detection device 100 repeatedly executes the process of the flowchart every time a predetermined time elapses.

[0122] Also, in step ST105, if the estimated information acquisition unit 110 is capable of acquiring interference estimated information from each of the multiple imaging devices 11-1, 11-2, ..., 11-N, or from an external device such as the image recording device 13, the processes from step ST101 to step ST104 are not essential processes.

[0123] In this embodiment, the interference identification unit 160 is configured to classify multiple imaging devices into two types of sets, i.e., a first set and a second set, but the interference identification unit 160 may also classify multiple imaging devices into three or more types of sets.

[0124] Furthermore, the number of sets of imaging devices defined in the interference identification unit 160, or the combination of imaging devices belonging to each set among the multiple sets, may be dynamically changed according to the current time or the current location of the vehicle. More specifically, for example, when the vehicle is parked in a garage at night and the luminance change is small in the image captured by the imaging device, the interference identification unit 160 classifies the set of imaging devices into one type based on the current time. On the other hand, for example, when the vehicle is operating commercially during the day and the luminance change is large in the image captured by the imaging device, the interference identification unit 160 classifies the set of imaging devices into two or more types based on the current time.

[0125] Alternatively, for example, when the vehicle is parked in the garage with some of the emergency lights turned on, the interference identification unit 160 sets the set of image capturing devices to two or more types based on the current position of the vehicle. On the other hand, when the vehicle is parked in the garage with all the lights turned on or off, the interference identification unit 160 sets the set of image capturing devices to one type based on the current position of the vehicle.

[0126] Alternatively, for example, when the vehicle is parked in the garage in a state where direct sunlight is shining into the vehicle interior, such as early in the morning or evening, the interference identification unit 160 sets the set of imaging devices to two or more types based on the current time and the current position of the vehicle, and when the vehicle is parked in the garage in any other environment, the interference identification unit 160 sets the set of imaging devices to one type based on the current time and the current position of the vehicle.

[0127] In the first embodiment, the image luminance acquisition unit 130 divides each image captured by a plurality of imaging devices into two partial images, acquires image luminance information indicating the luminance of each partial image in each image, and the interference estimation unit 150 generates interference estimation information based on the image luminance information. However, the interference estimation information of the present application is not limited to the interference estimation information.

[0128] For example, the image brightness acquisition unit 130 may divide the image into two parts, left and right, or may divide the image into two parts, top and bottom and left and right, to divide the image into a partial image where the shooting range of the imaging device 11-1 and the shooting range of the imaging device 11-2 overlap and a partial image where they do not overlap. In this case, the image brightness acquisition unit 130 may acquire image brightness information indicating the brightness of the left half and the right half of the image, or image brightness information indicating the brightness of the upper left, upper right, lower left, and lower right of the image, and the interference estimation unit 150 may generate interference estimation information based on the image brightness information.

[0129] With the above configuration, the photography tampering detection device 100 can reduce the possibility of erroneously determining that the photography tampering is in an abnormal photography state even though the photography devices are in a normal state when there is a bias in the brightness of each image captured by the multiple photography devices, and can accurately determine whether the photography tampering device installed in the railway vehicle is in an abnormal photography state. Also, with this configuration, the photography tampering detection device 100 can perform processing at high speed because the load on hardware such as a CPU is small compared to when determining the presence or absence of photography tampering based on an image determination technique such as pattern matching that compares image features to determine the presence or absence of photography tampering based on the brightness of the image.

[0130] Furthermore, since the system is configured to calculate the brightness for each of the multiple partial images, it is possible to reduce the possibility of failing to detect an abnormal shooting condition in cases where strong light falls on part of the image, such as when an emergency light is turned on in front of the camera.

[0131] As described above, the photography interference detection device 100 according to the first embodiment includes an estimated information acquisition unit 110 that acquires a plurality of interference estimation information indicating an estimation result as to whether or not a corresponding imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N is being interfered with in photography, and an interference identification unit 160 that classifies the plurality of imaging devices 11-1, 11-2, ..., 11-N into a plurality of sets and identifies whether or not a first imaging device is being interfered with in photography, based on interference estimation information corresponding to a first imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N, and interference estimation information corresponding to a second imaging device that belongs to the same set as the first imaging device among the plurality of imaging devices 11-1, 11-2, ..., 11-N, among the plurality of interference estimation information acquired by the estimated information acquisition unit 110.

[0132] According to the above configuration, whether or not the first imaging device is being interfered with is determined based on not only the interference estimation information corresponding to the first imaging device, but also the interference estimation information corresponding to the second imaging device belonging to the same group as the first imaging device, thereby improving the accuracy of determining whether or not the imaging device is being interfered with.

[0133] For example, when a vehicle is parked and external light enters the vehicle, or when the vehicle is parked with some of the interior lights turned on as emergency lights, the illuminance environment differs for each imaging device, causing a bias in the brightness of each image captured by the multiple imaging devices. By appropriately classifying a plurality of imaging devices into a plurality of groups according to the illumination environment in which the imaging devices are placed, it is possible to identify whether or not the imaging devices are being obstructed from photographing.

[0134] The tampering identifying section 160 in the photography tampering detection device 100 according to the first embodiment classifies the multiple image capture devices 11-1, 11-2, . . . , 11-N into multiple groups based on the current time. According to the above configuration, the first imaging device and the second imaging device can be classified into the same group based on the current time. Therefore, based on the interference estimation information corresponding to the first imaging device and the interference estimation information corresponding to the second imaging device, it is possible to suitably determine whether the first imaging device is being interfered with during shooting. Therefore, it is possible to improve the accuracy of determining whether the imaging device is being interfered with during shooting.

[0135] The tampering identification unit 160 in the photography tampering detection device 100 of embodiment 1 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple groups when the current time falls within the daytime zone, and does not classify the multiple imaging devices 11-1, 11-2, ..., 11-N when the current time falls within the nighttime zone.

[0136] According to the above configuration, the multiple imaging devices 11-1, 11-2, ..., 11-N are classified into multiple groups during the daytime when the change in the illuminance environment for the imaging devices is greater than at night. This makes it possible to classify the imaging devices and determine whether or not there is any sabotage based on the classification during the daytime when there is a higher possibility of erroneously determining that the imaging device is sabotaged even though the imaging device is not sabotaged.

[0137] The multiple imaging devices 11-1, 11-2, ..., 11-N in the photography tampering detection device 100 of embodiment 1 are installed in a vehicle, and the tampering identification unit 160 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple groups based on the current position of the vehicle.

[0138] According to the above configuration, the first imaging device and the second imaging device can be classified into the same group based on the current position of the vehicle. Therefore, based on the interference estimation information corresponding to the first imaging device and the interference estimation information corresponding to the second imaging device, it is possible to suitably identify whether the first imaging device is being interfered with during photography. Therefore, it is possible to improve the accuracy of determining whether the imaging device is being interfered with during photography.

[0139] The hindrance identification unit 160 in the photography hindrance detection device 100 of embodiment 1 classifies the multiple imaging devices 11-1, 11-2, ..., 11-N into multiple groups based on position influence information that corresponds, for each position, a position on the route along which the vehicle is traveling and sunlight influence information indicating whether or not each of the multiple imaging devices 11-1, 11-2, ..., 11-N is affected by sunlight when capturing an image at that position.

[0140] According to the above configuration, for example, imaging devices that are affected by sunlight when capturing an image can be classified into the same group. Therefore, for example, based on each interference estimation information corresponding to the first imaging device and the second imaging device that are affected by sunlight when capturing an image, it is possible to suitably identify whether the first imaging device is being interfered with during imaging. Therefore, it is possible to improve the accuracy of determining whether the imaging device is being interfered with during imaging.

[0141] The interference identification unit 160 in the photography interference detection device 100 of embodiment 1 identifies that none of the imaging devices are being interfered with in photography when, among the multiple interference estimation information acquired by the estimated information acquisition unit 110, all of the interference estimation information corresponding to each imaging device in the set to which the first imaging device and the second imaging device belong indicates an estimation result that the corresponding imaging device is being interfered with in photography.

[0142] According to the above configuration, in an unnatural situation in which all of the imaging devices classified into the same group are presumed to be subject to shooting interference, it is possible to appropriately identify that none of the imaging devices are subject to shooting interference, thereby improving the accuracy of determining whether or not the imaging devices are subject to shooting interference.

[0143] The estimated information acquisition unit 110 in the photography tampering detection device 100 of embodiment 1 further acquires, for an imaging device among the multiple imaging devices 11-1, 11-2, ..., 11-N that is estimated to be subject to photography tampering, estimated interference period information indicating an estimated interference period during which the imaging device is continuously estimated to be subject to photography tampering, and the interference identification unit 160 identifies whether or not the first imaging device is subject to photography tampering based further on the estimated interference period indicated by the estimated interference period information further acquired by the estimated information acquisition unit 110.

[0144] According to the above configuration, for example, in a situation where the imaging device is continuously interfered with in a state where the imaging device is more likely to be interfered with in a temporary state, it is possible to appropriately identify that the imaging device is being interfered with in a shooting state. Therefore, it is possible to improve the accuracy of determining whether the imaging device is being interfered with in a shooting state.

[0145] The photography interference detection device 100 according to the first embodiment further includes an image brightness acquisition unit 130 that divides each image captured by a plurality of imaging devices 11-1, 11-2, ..., 11-N into a plurality of partial images and acquires image brightness information indicating the brightness of each partial image in each of the images, a reference brightness acquisition unit 140 that acquires reference brightness information indicating a predetermined reference brightness corresponding to each of the plurality of imaging devices 11-1, 11-2, ..., 11-N, and a interference estimation unit 150 that generates a plurality of interference estimation information by estimating whether or not the imaging device is being interfered with in photography by comparing, for each imaging device, the brightness of each partial image indicated by the image brightness information acquired by the image brightness acquisition unit 130 and the reference brightness indicated by the reference brightness information acquired by the reference brightness acquisition unit 140, and the interference estimation unit 150. The estimation information acquisition unit 110 acquires the plurality of interference estimation information generated by the interference estimation unit 150.

[0146] According to the above configuration, even in a situation where the imaging device is partially obstructed from shooting, by comparing the luminance of each partial image with the reference luminance, it is possible to appropriately estimate for each imaging device whether the imaging device is obstructed from shooting. Then, based on the multiple obstruction estimation information thus generated, it is possible to appropriately identify whether the imaging device is obstructed from shooting. Therefore, it is possible to improve the accuracy of determining whether the imaging device is obstructed from shooting.

[0147] Although not described with reference to the drawings, the shooting interference detection device 100 may further include a shooting parameter acquisition unit and a reference shooting parameter acquisition unit. In this case, the shooting parameter acquisition unit acquires shooting parameter information indicating shooting parameters used when each of the multiple imaging devices 11-1, 11-2, . . . , 11-N captured an image. Examples of the shooting parameters here include ISO (International Organization for Standardization) sensitivity, shutter speed value, AE (Automatic Exposure) detection value, and AF (Autofocus) detection value. The reference shooting parameter acquisition unit acquires reference shooting parameter information indicating predetermined reference shooting parameters corresponding to each of the multiple imaging devices 11-1, 11-2, . . . , 11-N. Examples of the predetermined reference shooting parameters here include values ​​indicating the application range of shooting parameters such as ISO sensitivity value, shutter speed value, aperture value, and autofocus detection value, which are used as a reference when each of the multiple imaging devices 11-1, 11-2, . . . , 11-N captured an image. The interference estimation unit 150 may generate a plurality of interference estimation information by estimating for each imaging device whether or not the imaging device is being interfered with in the imaging process by comparing the imaging parameters indicated by the imaging parameter information acquired by the imaging parameter acquisition unit and the reference imaging parameters indicated by the reference imaging parameter information acquired by the reference imaging parameter acquisition unit for each imaging device. The estimation information acquisition unit 110 may acquire the plurality of interference estimation information thus generated by the interference estimation unit 150. With the above configuration, it is possible to appropriately estimate whether or not the imaging device is being interfered with in the imaging process.

[0148] Alternatively, although not described using a figure, the photography tampering detection system 1 may further include a plurality of other imaging devices having the same functions as the plurality of imaging devices 11-1, 11-2, . . . , 11-N, and a different photography tampering detection device having the same functions as the photography tampering detection device 100. In that case, the above-mentioned estimated information acquisition unit 110 may further acquire a plurality of other interference estimation information each indicating an estimation result of whether or not a corresponding imaging device among the plurality of other imaging devices is being interfered with in photography from the different photography tampering detection device. Then, when the plurality of interference estimation information (information on the imaging devices 11-1, 11-2, . . . , 11-N) acquired by the estimated information acquisition unit 110 all indicates an estimation result that the corresponding imaging device is being interfered with in photography, the above-mentioned interference identification unit 160 may identify whether or not each of the plurality of imaging devices 11-1, 11-2, . . . , 11-N is being interfered with in photography based on the plurality of other interference estimation information further acquired by the estimated information acquisition unit 110. For example, in such a configuration, the multiple imaging devices 11-1, 11-2, . . . , 11-N are installed in a first car connected to the train set, and another multiple imaging devices are installed in a second car connected to the train set. With the above configuration, it is possible to further improve the accuracy of determining whether or not the imaging devices are being obstructed from photographing.

[0149] Embodiment 2 Hereinafter, the second embodiment will be described with reference to the drawings. Note that components having the same functions as those described in the first embodiment are given the same reference numerals, and the description thereof will be omitted. 11 is a block diagram showing an example of a configuration of a main part of a photography tampering detection device 100a in a photography tampering detection system 1a according to embodiment 2. The photography tampering detection device 100a according to embodiment 2 differs from the photography tampering detection device 100 according to embodiment 1 in that it includes a time mode switching unit 180 and a position mode switching unit 181 that are not included in the photography tampering detection device 100 according to embodiment 1. The photography tampering detection device 100a in the photography tampering detection system 1a of embodiment 2 includes an estimated information acquisition unit 110, an image acquisition unit 120, an image brightness acquisition unit 130, a reference brightness acquisition unit 140, a tampering estimation unit 150, a tampering identification unit 160, an output control unit 170, a time mode switching unit 180, and a position mode switching unit 181.

[0150] The time mode switching unit 180 switches the operation mode of the photography tampering detection device 100a based on the current time to either a tampering detection mode in which each of the multiple imaging devices detects whether or not photography is being tampered with, or a tampering detection pause mode in which tampering detection that detects whether or not each of the multiple imaging devices is being tampered with is paused.

[0151] For example, when the time mode switching unit 180 switches the operating mode of the photography tampering detection device 100a to the tampering detection mode, the above-mentioned estimated information acquisition unit 110 acquires multiple pieces of tampering estimated information, and the above-mentioned tampering identification unit 160 identifies whether or not the first imaging device is being tampered with in photography by the above-mentioned method.

[0152] More specifically, in embodiment 1, the time mode switching unit 180 switches the operation mode of the photography tampering detection device 100a to the tampering detection pause mode when the current time falls within the daytime hours, and switches the operation mode of the photography tampering detection device 100a to the tampering detection mode when the current time falls within the nighttime hours.

[0153] More specifically, the time mode switching unit 180 switches between two operating modes, a tampering detection mode that detects whether or not there is tampering with photography for each of the multiple imaging devices 11-1, 11-2, ..., 11-N, and a detection pause mode that does not detect whether or not there is tampering with photography for each of the multiple imaging devices 11-1, 11-2, ..., 11-N, based on time information indicating the current time.

[0154] More specifically, for example, based on time zone information in which a time period during which each of the multiple imaging devices 11-1, 11-2, ..., 11-N is affected by sunlight when capturing images, and time information indicating the current time, the time mode switching unit 180 switches the operation mode so that each of the multiple imaging devices 11-1, 11-2, ..., 11-N operates in a detection pause mode during a time period during which each of the multiple imaging devices 11-1, 11-2, ..., 11-N is affected by sunlight when capturing images, and switches the operation mode so that each of the multiple imaging devices 11-1, 11-2, ..., 11-N operates in a tampering detection mode during a time period during which each of the multiple imaging devices 11-1, 11-2, ..., 11-N is not affected by sunlight when capturing images.

[0155] More specifically, for example, the time mode switching unit 180 switches the operation mode so that each of the multiple imaging devices 11-1, 11-2, ..., 11-N operates in a detection pause mode during daytime hours when the imaging devices are affected by sunlight, and switches the operation mode so that each of the multiple imaging devices 11-1, 11-2, ..., 11-N operates in a tamper detection mode during nighttime hours when the imaging devices are not affected by sunlight.

[0156] The time information is acquired, for example, by using a clock function (not shown) provided in the photography tampering detection device 100a. The clock function is similar to a clock function provided in an electronic device such as a known general-purpose computer, for example, and is a known technology, so a detailed description thereof will be omitted.

[0157] The time zone information is, for example, stored in advance in the time mode switching unit 180. Alternatively, for example, the time zone information may be acquired by the time mode switching unit 180 from a storage device (not shown) provided inside or outside the housing of the photography tampering detection device 100a, or from an external device such as the image recording device 13 via the communication network 12.

[0158] In this way, by including the time mode switching unit 180, the photography tampering detection device 100a detects the presence or absence of photography tampering for each of the multiple imaging devices 11-1, 11-2, ..., 11-N during a time period when each of the multiple imaging devices 11-1, 11-2, ..., 11-N is not affected by sunlight when taking pictures, thereby reducing erroneous detections.

[0159] The position mode switching unit 181 switches the operation mode of the photography tampering detection device to either a tampering detection mode in which each of the multiple imaging devices detects whether or not photography is being tampered with, or a tampering detection pause mode in which the tampering detection that detects whether or not each of the multiple imaging devices is being tampered with is paused based on the current position of the vehicle.

[0160] In addition, when the position mode switching unit 181 switches the operation mode of the photography tampering detection device 100a to the tampering detection mode, the above-mentioned estimated information acquisition unit 110 acquires multiple pieces of tampering estimated information, and the tampering identification unit 160 identifies whether or not the first imaging device is being tampered with in photography by the above-mentioned method.

[0161] More specifically, the position mode switching unit 181 determines whether the current position is a position where the multiple imaging devices are affected by sunlight when they capture images, based on the position influence information in which the position on the route on which the vehicle travels is associated with sunlight influence information indicating whether the multiple imaging devices are affected by sunlight when they capture images at that position for each position. When the interference identification unit 160 determines that the current position is a position where the multiple imaging devices are affected by sunlight when they capture images, it switches the operation mode of the photography interference detection device 100a to the interference detection pause mode. When the interference identification unit 160 determines that the current position is not a position where the multiple imaging devices are affected by sunlight when they capture images, it switches the operation mode of the photography interference detection device 100a to the interference detection mode.

[0162] More specifically, the position mode switching unit 181 switches between two operating modes, a tampering detection mode that detects whether or not there is tampering with photography for each of the multiple imaging devices 11-1, 11-2, ..., 11-N, and a detection pause mode that does not detect whether or not there is tampering with photography for each of the multiple imaging devices 11-1, 11-2, ..., 11-N, based on position information that indicates the position where the railway vehicle 10 is traveling.

[0163] More specifically, for example, based on position influence information in which information indicating each of a plurality of positions on the route along which the railway vehicle 10 travels is pre-associated with sunlight influence information indicating the presence or absence of sunlight influence when each of the plurality of imaging devices 11-1, 11-2, ..., 11-N captures an image at each position, and information regarding the current position, the position mode switching unit 181 switches the operation mode to operate in the detection pause mode when the railway vehicle 10 travels through a position that is affected by sunlight when each of the plurality of imaging devices 11-1, 11-2, ..., 11-N captures an image, and switches the operation mode to operate in the interference detection mode when the railway vehicle 10 travels through a position that is not affected by sunlight when each of the plurality of imaging devices 11-1, 11-2, ..., 11-N captures an image.

[0164] More specifically, for example, the position mode switching unit 181 switches the operation mode to operate in a detection pause mode when the railway vehicle 10 travels on ground where the influence of sunlight is felt when each of the multiple imaging devices 11-1, 11-2, ..., 11-N captures images, and switches the operation mode to operate in an interference detection mode when the railway vehicle 10 travels underground where the influence of sunlight is not felt when each of the multiple imaging devices 11-1, 11-2, ..., 11-N captures images.

[0165] The position information is acquired, for example, using a running position detection function (not shown) provided on the railcar 10 or a train to which the railcar 10 is coupled. The running position detection function detects the position of the railcar 10 by using a global navigation satellite system (GNSS) such as a global positioning system (GPS). A position detection method using a GNSS is well known, and therefore a detailed description thereof will be omitted.

[0166] The position influence information is, for example, stored in advance in the position mode switching unit 181. Alternatively, for example, the position influence information may be acquired by the position mode switching unit 181 from a storage device (not shown) provided inside or outside the housing of the photography tampering detection device 100a, or from an external device such as the image recording device 13 via the communication network 12.

[0167] In this way, by including the position mode switching unit 181, the photography tampering detection device 100a detects the presence or absence of photography tampering for each of the multiple imaging devices 11-1, 11-2, ..., 11-N at a position that is not affected by sunlight when each of the multiple imaging devices 11-1, 11-2, ..., 11-N takes pictures, thereby reducing erroneous detection.

[0168] It should be noted that the photographing tampering detection device 100a may include either the time mode switching unit 180 or the position mode switching unit 181, or may include both the time mode switching unit 180 and the position mode switching unit 181.

[0169] For example, if the photography tampering detection device 100a is equipped with both the time mode switching unit 180 and the position mode switching unit 181, the photography tampering detection device 100a may operate in the tampering detection mode during a time period in which the operation mode is set to the tampering detection mode by the time mode switching unit 180, and may operate in the tampering detection mode only at positions in which the operation mode is set to the tampering detection mode by the position mode switching unit 181 during a time period in which the operation mode is set to the detection pause mode by the time mode switching unit 180.

[0170] 9A and 9B in the first embodiment, the hardware configuration of the main parts of the photography tampering detection device 100a is not illustrated and will not be described. That is, the functions of the estimated information acquisition unit 110, the image acquisition unit 120, the image brightness acquisition unit 130, the reference brightness acquisition unit 140, the interference estimation unit 150, the interference identification unit 160, the output control unit 170, the time mode switching unit 180, and the position mode switching unit 181 may be realized by a processor 901 and a memory 902, or may be realized by a processing circuit 903.

[0171] 12 is a flowchart for explaining an example of processing of the photography tampering detection device 100a in the photography tampering detection system 1a according to embodiment 2. Processing of the photography tampering detection device 100a in the photography tampering detection system 1a according to embodiment 2 will be explained with reference to the drawing.

[0172] The photographing tampering detection device 100a repeatedly executes the processing of the flowchart shown in Figure 12 as the preliminary processing of the processing of the flowchart shown in Figure 10, and the photographing tampering detection system 1a executes the processing of the flowchart shown in Figure 10 only when the operating mode is the tampering detection mode.

[0173] First, in step ST1201, the time mode switching section 180 determines whether or not the current time is in a time zone affected by sunlight. If, in step ST1201, the time mode switching section 180 determines that the current time is not in a time period affected by sunlight, in step ST1202, the time mode switching section 180 switches the operation mode to the tampering detection mode.

[0174] After step ST1202, the photographing tampering detection device 100a ends the process of the flowchart, and repeats the process of the flowchart. If, in step ST1201, the time mode switching section 180 determines that the current time is in a time period affected by sunlight, in step ST1203, the time mode switching section 180 switches the operation mode to the detection pause mode.

[0175] After step ST1203, in step ST1204, the position mode switching unit 181 determines whether or not the position in which the railcar 10 is traveling is a position that is affected by sunlight. In step ST1204, if the position mode switching unit 181 determines that the position in which the railway vehicle 10 is traveling is a position that is affected by sunlight, the photography tampering detection device 100a terminates the processing of the flowchart, and the photography tampering detection device 100a repeatedly executes the processing of the flowchart.

[0176] If the position mode switching unit 181 determines in step ST1204 that the position in which the railcar 10 is traveling is not a position that is affected by sunlight, the position mode switching unit 181 switches the operation mode to the interference detection mode in step ST1205. After step ST1205, the photographing tampering detection device 100a ends the process of the flowchart, and repeats the process of the flowchart.

[0177] With the above configuration, the photography tampering detection device 100a can accurately determine whether the imaging devices installed in the railway vehicle are in an abnormal photography state. Also, with this configuration, the photography tampering detection device 100a detects the presence or absence of photography tampering for each of the multiple imaging devices 11-1, 11-2, ..., 11-N during a time period when each of the multiple imaging devices 11-1, 11-2, ..., 11-N is not affected by sunlight when taking pictures, so that erroneous detection can be suppressed.

[0178] Note that the photographing tampering detection device 100 or the photographing tampering detection device 100a may detect the presence or absence of photographing tampering by using photographing parameters at the time of photographing an image, such as the color tone or focus level of the image, instead of the brightness of the image. Furthermore, the photographing tampering detection device 100 or the photographing tampering detection device 100a can be applied not only to the railroad car 10 but also to vehicles such as large passenger buses or buildings such as houses. It should be noted that the embodiments may be freely combined, any of the components in each embodiment may be modified, or any of the components in each embodiment may be omitted. [Industrial Applicability]

[0179] The photography tampering detection device according to the present disclosure can be applied to a photography tampering detection system. The photography tampering detection device according to the present disclosure can be applied not only to railroad cars but also to vehicles such as large passenger cars or buildings such as houses. [Explanation of symbols]

[0180] 1, 1a, 1b, 1c Photography tampering detection system, 10, 10-1, ···, 10-m, ···, 10-M Railway vehicle, 11-1, 11-2, ···, 11-N, 11-1-1, 11-2-1, ···, 11-N-1, 11-1-m, 11-2-m, ···, 11-Nm, 11-1-M, 11-2-M, ···, 11-NM Imaging device, 12 Communication network, 13 Image recording device, 14 Display device, 14-1, 14-2, 14-3, 14-4 Light emitter, 100, 100a, 100b, 100b-1, 100b-2, ···, 100b-M, 100c Photography tampering detection device, 110 Estimated information acquisition unit, 111 Shooting parameter estimation information acquisition unit, 120 image acquisition unit, 130 image brightness acquisition unit, 131 shooting parameter acquisition unit, 140 reference brightness acquisition unit, 141 reference shooting parameter acquisition unit, 150 interference estimation unit, 151 shooting parameter interference estimation unit, 160, 160b, 160c interference identification unit, 170 output control unit, 180 time mode switching unit, 181 position mode switching unit, 901 processor, 902 memory, 903 processing circuit.

Claims

1. an estimation information acquisition unit for acquiring a plurality of pieces of interference estimation information indicating an estimation result of whether or not a corresponding imaging device among a plurality of imaging devices classified into a plurality of groups according to an illumination environment in which the imaging device is installed is being interfered with; a disturbance identification unit that identifies whether or not the first imaging device is being disturbed in photography based on the disturbance estimation information corresponding to a first imaging device among the plurality of imaging devices and the disturbance estimation information corresponding to a second imaging device among the plurality of imaging devices that belongs to the same group as the first imaging device, among the plurality of disturbance estimation information acquired by the estimated information acquisition unit.

2. A photography tampering detection device that determines whether photography tampering is occurring with a plurality of imaging devices installed in a vehicle, an estimation information acquisition unit that acquires a plurality of pieces of interference estimation information indicating an estimation result of whether or not a corresponding imaging device among the plurality of imaging devices classified into a plurality of groups according to whether the imaging device is installed in a passenger compartment or outside the passenger compartment of the vehicle; a disturbance identification unit that identifies whether or not the first imaging device is being disturbed in photography based on the disturbance estimation information corresponding to a first imaging device among the plurality of imaging devices and the disturbance estimation information corresponding to a second imaging device among the plurality of imaging devices that belongs to the same group as the first imaging device, among the plurality of disturbance estimation information acquired by the estimated information acquisition unit.

3. The photography tampering detection device according to claim 1 , The plurality of imaging devices; an output control unit that outputs an identification display signal for identifying the first imaging device identified as being subject to imaging interference when the interference identification unit identifies the first imaging device as being subject to imaging interference; A photography tampering detection system comprising: a display device that displays the identification display signal output by the output control unit.

4. The photography tampering detection device according to claim 2 ; The plurality of imaging devices; an output control unit that outputs an identification display signal for identifying the first imaging device identified as being subject to imaging interference when the interference identification unit identifies the first imaging device as being subject to imaging interference; A photography tampering detection system comprising: a display device that displays the identification display signal output by the output control unit.

5. an estimation information acquisition unit for acquiring a plurality of pieces of interference estimation information each indicating an estimation result of whether or not a corresponding imaging device among a plurality of imaging devices classified into a plurality of groups according to an illumination environment in which the imaging device is installed is being interfered with; an interference identification unit that identifies whether or not the first imaging device is being interfered with in photography based on interference estimation information corresponding to a first imaging device among the plurality of imaging devices and interference estimation information corresponding to a second imaging device among the plurality of imaging devices that belongs to the same group as the first imaging device, among the plurality of interference estimation information acquired by the estimation information acquisition unit; A program for detecting tampering with photography that allows a computer to function as a

6. A photography tampering detection program for determining whether photography tampering is occurring with a plurality of imaging devices installed in a vehicle, an estimation information acquisition unit that acquires a plurality of pieces of interference estimation information indicating an estimation result as to whether or not a corresponding imaging device among the plurality of imaging devices classified into a plurality of groups according to whether the imaging device is installed in a passenger compartment or outside the passenger compartment of the vehicle; an interference identification unit that identifies whether or not the first imaging device is being interfered with in photography based on interference estimation information corresponding to a first imaging device among the plurality of imaging devices and interference estimation information corresponding to a second imaging device among the plurality of imaging devices that belongs to the same group as the first imaging device, among the plurality of interference estimation information acquired by the estimation information acquisition unit; A program for detecting tampering with photography that allows a computer to function as a

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