Position identifying system for surveillance camera

Abstract

Provided is a system for identifying the position of a surveillance camera.　The system comprises a plurality of first devices, a surveillance camera, and a second device provided in the surveillance camera. The system also comprises: a distance calculation means for calculating the distance between each of the plurality of first devices and the second device on the basis of a signal propagation time or information on each of the plurality of first devices and the second device; and a position identifying means for identifying the position of the second device on the basis of the calculated distance between each of the plurality of first devices and the second device.

Description

Surveillance camera location system

[0001] The present invention relates to a system, a method, and a surveillance camera.

[0002] For crime prevention purposes, surveillance cameras are used to capture images of specific objects. Images captured by surveillance cameras are sometimes used as evidence in criminal investigations. However, there are cases where the location captured in the image and / or the location of the surveillance camera cannot be identified from the image.

[0003] At least one object of the present invention is to provide a system for locating a surveillance camera.

[0004] The present invention addresses the following problems: [1] A system comprising a plurality of first devices, a surveillance camera, and a second device provided in the surveillance camera, the system comprising: a distance calculation means for calculating a distance between each of the plurality of first devices and the second device based on a propagation time of information or signals between each of the plurality of first devices and the second device; and a position identification means for identifying a position of the second device based on the calculated distance between each of the plurality of first devices and the second device; [2] The system according to [1], in which one surveillance camera is provided with at least two second devices, the distance calculation means calculates a distance between each of the plurality of first devices and one of the second devices, and calculates a distance between each of the plurality of first devices and the other of the second devices, the position identification means respectively identifies the position of one of the second devices and the position of the other of the second devices, and the system comprises an orientation identification means for identifying an orientation of the surveillance camera based on the position of one of the second devices and the position of the other of the second devices; [3] The system according to [1] or [2], wherein one surveillance camera is provided with at least two second devices, and the two second devices are provided so that a vector corresponding to a line segment connecting the two second devices is parallel to a vector corresponding to the visual axis of one surveillance camera; [4] The system according to any of [1] to [3], which includes a storage means for storing the identified position of the second device, and the data for the position stored in the storage means cannot be changed or deleted; [5] The system according to any of [1] to [4], which includes a display control means for controlling to display the identified position on a map; [6] The system according to any of [1] to [5], wherein the distance calculation means calculates the distance between the first device and the second device based on the time difference between the internal clock of one first device and the internal clock of the second device; [7] The system according to any one of [1] to [6], comprising a time difference calculation means for calculating a time difference between the first device and the second device by performing communication between the first device and the second device, and a time correction means for correcting the time in the second device based on the calculated time difference; [8] The system according to any one of [1] to [7], comprising a phase difference calculation means for calculating a phase difference between the clocks of the first device and the second device by performing communication between the first device and the second device, and a phase correction means for correcting the phase in the second device based on the calculated phase difference;[9] A method executed in a system comprising a plurality of first devices, a surveillance camera, and a second device provided in the surveillance camera, the method comprising: a distance calculation step of calculating a distance between each of the plurality of first devices and the second device based on a propagation time of information or a signal between each of the plurality of first devices and the second device; and a position determination step of determining a position of the second device based on the calculated distance between each of the plurality of first devices and the second device;

[10] A surveillance camera provided with a second device capable of communicating with a plurality of first devices;

[11] The surveillance camera according to

[10] , provided with at least two second devices, and provided such that a vector corresponding to a line segment connecting two second devices is parallel to a vector corresponding to a visual axis of one surveillance camera;

[12] A system comprising a plurality of first devices, an object, and at least two second devices provided on the object, the system comprising: a distance calculation means for calculating a distance between each of the plurality of first devices and the second device based on a propagation time of information or a signal between each of the plurality of first devices and the second device; and a position determination means for determining a position of the second device based on the calculated distance between each of the plurality of first devices and the second device, wherein the distance calculation means calculates a distance between each of the plurality of first devices and one of the second devices, and calculates a distance between each of the plurality of first devices and the other of the second devices, the position determination means determines the position of one of the second devices and the position of the other of the second devices, respectively, and further comprises an orientation determination means for determining a direction and / or inclination of the object based on the position of one of the second devices and the position of the other of the second devices;

[13] The system according to

[12] , wherein the object is a moving body, a solar panel, a telescope, an antenna, a wind vane, a thumb turn, a building, and / or a road;

[14] A method executed in a system including a plurality of first devices, an object, and at least two second devices provided on the object, the method comprising: a distance calculation step of calculating a distance between each of the plurality of first devices and the second device based on a propagation time of information or signals between each of the plurality of first devices and the second device; and a position determination step of determining a position of the second device based on the calculated distances between each of the plurality of first devices and the second device, wherein the distance calculation step calculates a distance between each of the plurality of first devices and one second device, and a distance between each of the plurality of first devices and the other second device, the position determination step determines the position of one second device and the position of the other second device, respectively; and further comprising an orientation determination step of determining a direction and / or tilt of the object based on the position of one second device and the position of the other second device.

[0005] According to the present invention, a system for identifying the location of a surveillance camera can be provided.

[0006] FIG. 1 is a block diagram showing a system configuration according to an embodiment of the present invention. FIG. 2 is a block diagram showing a hardware configuration of a first device according to an embodiment of the present invention. FIG. 3 is a block diagram showing a hardware configuration of a second device according to an embodiment of the present invention. FIG. 4 is a block diagram showing a hardware configuration of a server device according to an embodiment of the present invention. FIG. 5 is a block diagram showing a hardware configuration of an administrator terminal according to an embodiment of the present invention. FIG. 6 is a diagram showing a flowchart of a distance calculation process according to an embodiment of the present invention. FIG. 7 is a diagram showing a flowchart of a position identification process according to an embodiment of the present invention. FIG. 8 is a diagram showing an example of an execution screen according to an embodiment of the present invention.

[0007] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following description of the effects of the present invention is one aspect of the effects of the embodiments of the present invention and is not limited to those described herein. The order of the processes constituting the flowcharts described below is random as long as no contradictions or inconsistencies occur in the process content. Furthermore, it is also possible to omit some of the processes constituting the flowcharts or add new processes to the processes constituting the flowcharts as long as no contradictions or inconsistencies occur in the process content. Furthermore, the device that executes each process constituting the flowcharts can be changed to another device as long as this does not violate the spirit of the present invention. In this case, the process content can be changed so as not to cause contradictions or inconsistencies in the process content.

[0008] [System Configuration] Fig. 1 is a block diagram showing the configuration of a system according to an embodiment of the present invention. The system 10 shown in Fig. 1 is composed of four first devices 1 (1a to 1d), two second devices 2 (2a and 2b), a surveillance camera 3, a server device 4, and an administrator terminal 5. As shown in the figure, the second device 2 is provided in the surveillance camera 3. The administrator terminal 5 is operated by an administrator who manages the system 10.

[0009] The number of first devices 1 included in the system of the present invention is not particularly limited and can be designed as appropriate. The system of the present invention may include a plurality of first devices 1. It is preferable that the system of the present invention include at least four first devices 1.

[0010] Furthermore, the number of second devices 2 included in the system of the present invention is not particularly limited and can be designed as appropriate. The system of the present invention may include one or more second devices 2. At least two second devices 2 may be provided for one surveillance camera 3. The system of the present invention may also include multiple surveillance cameras 3.

[0011] The first device 1 and the second device 2 can be directly connected for communication. The first device 1 can be connected for communication with the server device 4 and the administrator terminal 5 via the communication network 6. The second device 2 can be connected for communication with the server device 4 and the administrator terminal 5 via the communication network 6. Note that in FIG. 1 , arrows representing communication connections between the second device 2b and each of the first devices 1 (1a to 1d) and between the second device 2b and the communication network 6 are omitted. The surveillance camera 3 may be connected for communication with the server device 4 and the administrator terminal 5 via the communication network 6.

[0012] The first device 1 is a reference device for synchronizing the clocks of the second devices 2, and one first device 1 can also function as the first device for multiple second devices 2.

[0013] The second device 2 can be connected to the first device 1 and the server device 4. In this system, the time of the second device 2 is synchronized based on the time clocked by the first device 1, and the phase of the signal generated by the oscillator in the second device 2 is synchronized based on the phase of the signal generated by the oscillator in the first device 1.

[0014] The first device 1 of the present invention will now be described. Fig. 2 is a diagram showing the hardware configuration of the first device according to an embodiment of the present invention. The first device 1 includes a control unit 11, an RF chip 12, and an oscillator 13. The RF chip 12 includes a clock 12a and a phase detector 12b. In addition to the control unit 11, the RF chip 12, the oscillator 13, the clock 12a, and the phase detector 12b, the first device 1 may include other components as necessary.

[0015] The control unit 11 is not particularly limited, but may be, for example, a microcomputer (microcontroller). The control unit 11 executes programs based on programs and data. The RF chip 12 receives and transmits radio signals. The data received by the RF chip 12 is subjected to arithmetic processing by the control unit 11.

[0016] The oscillator 13 oscillates at a predetermined frequency and outputs a signal that provides operational timing for each component of the device. An atomic oscillator or a quartz oscillator can be used as the oscillator 13. The clock 12a uses the output signal from the oscillator 13 as a source of oscillation to clock and output the time. The control unit 11 controls the clock 12a to transmit the time to the second device 2 via the RF chip 12. The phase detector 12b detects the phase of the carrier wave that constitutes the information received from the second device 2, and detects the phase of the signal oscillated by the oscillator 13 in the first device 1.

[0017] The installation location of the first device 1 is not particularly limited. The first device 1 may be installed outdoors or indoors. When the first device 1 is installed outdoors, the first device 1 may be installed, for example, on a transmission tower supporting an overhead power line. As described below, the position of the surveillance camera 3 is determined based on the distance between the multiple first devices 1 and the second devices 2 provided on the surveillance camera 3. Therefore, multiple first devices 1 may be arranged in a grid pattern to cover an area in which the position of the surveillance camera 3 (second devices 2) can be determined. Preferably, the position of the first device 1 is determined in advance and the first device 1 is installed in a fixed location. Location information corresponding to the installation location of the first device 1 (hereinafter also referred to as location information of the first device 1) may be pre-stored in a storage unit of the server device 4, for example. The location information of the first device 1 may be represented by latitude, longitude, and altitude, or by XYZ coordinates in a predetermined coordinate space.

[0018] Identification information (e.g., a first device ID) for identifying the first device 1 may be set for each of the multiple first devices 1. Hereinafter, the identification information for identifying the first device 1 is referred to as the first device ID. Location information of the first device 1 may be stored in the server device 4 in association with the first device ID.

[0019] The second device 2 of the present invention will now be described. Fig. 3 is a block diagram showing the hardware configuration of the second device according to an embodiment of the present invention. The second device 2 includes a control unit 21, an RF chip 22, and an oscillator 23, which are connected to each other via a bus. The RF chip 22 includes a clock 22a and a phase detector 22b. In addition to the control unit 21, the RF chip 22, the oscillator 23, the clock 22a, and the phase detector 22b, the second device 2 may include other components as necessary.

[0020] The control unit 21 is not particularly limited, but may be, for example, a microcomputer. The control unit 21 executes programs based on programs and data. The RF chip 22 receives and transmits radio signals. The data received by the RF chip 22 is subjected to arithmetic processing by the control unit 21.

[0021] The oscillator 23 oscillates at a predetermined frequency and outputs a signal that provides operational timing for each component of the device. A crystal oscillator, for example, can be used as the oscillator 23. The clock 22a uses the output signal from the oscillator 23 as a source of oscillation to clock and output the time. The control unit 21 controls the clock 22a to transmit the time to the first device 1 via the RF chip 22. The phase detector 22b detects the phase of the carrier wave that constitutes the information received from the first device 1, and detects the phase of the signal oscillated by the oscillator 23 of the second device 2.

[0022] Next, the surveillance camera of the present invention will be described. The surveillance camera 3 is not particularly limited as long as it is capable of capturing an image of a predetermined object. The surveillance camera 3 preferably includes an imaging unit, a control unit, a storage unit, and a communication interface. The surveillance camera 3 may also include any other configuration.

[0023] The surveillance camera 3 may be mobile or fixed. If the surveillance camera 3 is mobile, it may be one that moves in the air, on land, or underwater. For example, the surveillance camera 3 may be provided on a mobile object such as a drone or an autonomous robot. Alternatively, for example, the surveillance camera 3 may be provided on an object that can be worn by a person or the like and moved, such as glasses, or on an object that can be carried by a person or the like and moved, such as a flashlight.

[0024] If the surveillance camera 3 is a fixed type, the surveillance camera 3 may have a so-called oscillating function that allows it to change the shooting direction, or it may not have a oscillating function. If the surveillance camera 3 has a oscillating function, it may oscillate at predetermined time intervals, may oscillate in response to operation by the photographer, or may oscillate to automatically track an object that meets predetermined conditions. The predetermined conditions may be movement or a predetermined appearance. The location where the surveillance camera 3 is installed is not particularly limited and can be designed as appropriate.

[0025] The surveillance camera 3 may have one lens, or may have two or more lenses, a so-called 360-degree camera. A surveillance camera 3 with one lens can capture images in the direction of the lens, i.e., the direction the surveillance camera 3 is facing, while a 360-degree camera can capture images in all directions around the surveillance camera 3.

[0026] The images captured by the surveillance camera 3 may be still images or moving images. The surveillance camera 3 may store the captured images in a storage unit provided in the surveillance camera 3. The stored images may be displayable on any display device. Alternatively, the surveillance camera 3 may transmit the captured images to the server device 4, the administrator terminal 5, another computer device (e.g., a terminal operated by a photographer other than the administrator) via the communication network 6. In this case, the captured images can be stored in the storage unit of the destination device. The communication connection between the surveillance camera 3 and the display device, the server device 4, the administrator terminal 5, another computer device, etc. may be wired or wireless.

[0027] The purpose for installing the surveillance camera 3 is not particularly limited and can be appropriately designed. For example, the purpose for installing the surveillance camera 3 may be crime prevention or disaster prevention.

[0028] The object to be monitored and / or photographed by the surveillance camera 3 is not particularly limited, but may be, for example, equipment within a facility such as a factory or office. In this case, the server device 4 may use AI image analysis based on the images photographed by the surveillance camera 3 to detect abnormalities in the facility or equipment.

[0029] The position at which the second device 2 is attached to the surveillance camera 3 is not particularly limited and can be designed as appropriate. The second device 2 may be built into the housing of the surveillance camera 3, or may be installed outside the housing (for example, on the top or side of the surveillance camera 3).

[0030] Identification information (e.g., a surveillance camera ID) for identifying the surveillance camera 3 may be set for each of the multiple surveillance cameras 3. Furthermore, identification information (e.g., a second device ID) for identifying the second device 2 may be set for each of the second devices 2. Hereinafter, the identification information for identifying the surveillance camera 3 will be referred to as the surveillance camera ID, and the identification information for identifying the second device 2 will be referred to as the second device ID. The second device ID may be stored in the server device 4 in association with the surveillance camera ID. Even if two second devices 2 are provided in the surveillance camera 3, if the second device ID can be identified, the corresponding surveillance camera ID can be identified.

[0031] Next, the server device of the present invention will be described. Fig. 4 is a block diagram showing the hardware configuration of the server device according to an embodiment of the present invention. The server device 4 includes at least a control unit 41, a RAM 42, a storage unit 43, and a communication interface 44, which are connected to each other via an internal bus.

[0032] The control unit 41 is composed of a CPU and ROM, and executes programs stored in the storage unit 43 to control the server device 4. The control unit 41 also has an internal timer that measures time. The RAM 42 is the work area of ​​the control unit 41. The storage unit 43 is a memory area for saving programs and data. The control unit 41 reads the programs and data from the RAM 42 and performs program execution processing based on information received from the first device 1, the second device 2, or the administrator terminal 5.

[0033] The server device 4 may function in a distributed manner across multiple computer devices. For example, a distributed ledger technology such as a blockchain may be used instead of the server device 4. Alternatively, for example, a distributed ledger technology such as a blockchain may be used in combination with the server device 4.

[0034] 5 is a block diagram showing the hardware configuration of an administrator terminal according to an embodiment of the present invention. The administrator terminal 5 includes a control unit 51, a RAM 52, a storage unit 53, an input unit 54, a display unit 55, and a communication interface 56, all of which are connected to each other via an internal bus.

[0035] The control unit 51 is composed of a CPU and a ROM. The control unit 51 executes programs stored in the storage unit 53 and controls the administrator terminal 5. The RAM 52 is a work area for the control unit 51. The storage unit 53 is a memory area for saving programs and data. In other words, the storage unit 53 functions as a recording medium that stores programs. The control unit 51 performs arithmetic processing based on the programs and data read from the RAM 52 and data input via the input unit 54.

[0036] The display unit 55 has a display screen. The control unit 51 outputs a video signal for displaying an image on the display screen in accordance with the result of the arithmetic processing. Here, the display screen of the display unit 55 may be a touch panel equipped with a touch sensor. In this case, the touch panel functions as the input unit 54.

[0037] The communication interface 56 can be connected to the communication network 6 wirelessly or via a wire, and can transmit and receive data to and from other computer devices via the communication network 6. Data received via the communication interface 56 is loaded into the RAM 52, and the control unit 51 performs arithmetic processing on the data.

[0038] The program may also be stored in a recording medium such as a CD-ROM. In this case, the program stored in the recording medium may be installed in the server device 4 and / or the administrator terminal 5 to execute a predetermined function.

[0039] Alternatively, the program may be distributed from a computer device external to the system 10. In this case, the program distributed from the computer device external to the system 10 may be installed in the server device 4 and / or the administrator terminal 5 to execute a predetermined function.

[0040] Below, an embodiment of using the system of the present invention to identify the position of a surveillance camera 3 will be described. According to the system 10, the distance between each of the multiple first devices 1 and the second device 2 can be calculated by communication between each of the multiple first devices 1 and the second device 2. Furthermore, the position of the second device 2 can be identified based on the multiple calculated distances. By attaching the second device 2 to the surveillance camera 3, the position of the surveillance camera 3 can be identified.

[0041] Furthermore, since the distance between the first device 1 and the second device 2 is calculated based on the propagation time of communication between the first device 1 and the second device 2, the smaller the time and phase difference between the internal clocks of the first device 1 and the second device 2, the more accurate the distance can be calculated. Below, an example will be described in which the internal clocks of the first device 1 and the second device 2 are synchronized and then the distance between the first device 1 and the second device 2 is calculated.

[0042] 6 is a flowchart of the distance calculation process according to the embodiment of the present invention. The order of the processes constituting the flowchart may be random as long as no contradiction or inconsistency occurs in the process content.

[0043] The distance calculation process can be executed, for example, at predetermined time intervals or whenever a predetermined condition is satisfied. For example, the distance calculation process can be executed a predetermined number of times per second, once every few seconds, once every few hours, or once a day.

[0044] First, information or a signal is transmitted from the first device 1 to the second device 2 (step S1). There are no particular restrictions on the information or signal transmitted from the first device 1 to the second device 2. The first device 1 clocks the time when the information or signal was transmitted in step S1 and measures the phase at the time of transmission (step S2). The clocked time and the measured phase are then stored in the memory of the control unit 11 (step S3).

[0045] Next, the second device 2 receives the information or signal from the first device 1 (step S4). The second device 2 clocks the time when the information or signal was received in step S4 and measures the phase at the time of reception (step S5). The clocked time and the measured phase are then stored in the memory of the control unit 21 (step S6).

[0046] Next, the second device 2 transmits information or a signal to the first device 1 (step S7). There are no particular restrictions on the information or signal transmitted from the second device 2 to the first device 1. The second device 2 clocks the time when the information or signal was transmitted in step S7 and measures the phase at the time of transmission (step S8). The clocked time and the measured phase are then stored in the memory of the control unit 21 (step S9).

[0047] The first device 1 receives the information or signal transmitted in step S7 (step S10). The first device 1 clocks the time when the information or signal was received in step S10 and measures the phase at the time of reception (step S11). The clocked time and the measured phase are then stored in the memory of the control unit 11 (step S12). After step S12 is completed, the process proceeds to step S13.

[0048] The first device 1 transmits to the second device 2 via the RF chip 12 the information stored in step S3 regarding the time when the signal was transmitted in step S1 and the phase at the time of transmission, and the information stored in step S12 regarding the time when the signal was received in step S10 and the phase at the time of reception (step S13).

[0049] Then, the second device 2 receives information regarding the time and phase at the time of transmission when the first device 1 transmitted the information or signal in step S1, and information regarding the time and phase at the time of reception when the first device 1 received the information or signal in step S10 (step S14).

[0050] Next, the control unit 21 of the second device 2 calculates the phase shift between the phase of the signal generated by the oscillator 13 of the first device 1 and the phase of the signal generated by the oscillator 23 of the second device 2 (step S15). The phase shift can be calculated based on the phase difference between the phase of the carrier wave constituting the information or signal transmitted from the first device 1 to the second device 2 and the phase of the signal oscillated by the oscillator 23 of the second device 2 when the information or signal is received by the second device 2, and the phase difference between the phase of the carrier wave constituting the information or signal transmitted from the second device 2 to the first device 1 and the phase of the signal oscillated by the oscillator 13 of the first device 1 when the information or signal is received by the first device 1.

[0051] The phase of the carrier wave constituting the information or signal transmitted from the first device 1 to the second device 2 is the phase of the information or signal transmitted in step S1. Information regarding this phase is transmitted from the first device 1 to the second device 2 in step S13. The phase of the signal oscillated by the oscillator 23 of the second device 2 when the second device 2 receives the information or signal is the phase of the information or signal received in step S4. The information regarding this phase is measured by the second device 2 in step S5 and stored in step S6. The phase of the carrier wave constituting the information or signal transmitted from the second device 2 to the first device 1 is, for example, the phase of the information or signal transmitted in step S7. The information regarding this phase is stored by the second device 2 in step S9. The phase of the signal oscillated by the oscillator 13 of the first device 1 when the first device 1 receives the information or signal is, for example, the phase of the information or signal received in step S10. The information regarding this phase is measured in step S11 and transmitted from the first device 1 to the second device 2 in step S13.

[0052] Here, the phase of the carrier wave constituting the information or signal transmitted from the first device 1 to the second device 2 is a concept that includes not only the phase of the carrier wave constituting the information or signal transmitted from the first device 1 to the second device 2, but also the phase of the carrier wave constituting the signal obtained by mixing down this information or signal. Similarly, the phase of the carrier wave constituting the information or signal transmitted from the second device 2 to the first device 1 is a concept that includes not only the phase of the carrier wave constituting the information or signal transmitted from the second device 2 to the first device 1, but also the phase of the carrier wave constituting the signal obtained by mixing down this information or signal.

[0053] The phase difference between the phase of the carrier wave constituting the information or signal transmitted from the first device 1 to the second device 2 and the phase of the signal oscillated by the oscillator 23 of the second device 2 when the information or signal is received by the second device 2 is defined as ΔΦ Ｓ and the phase difference between the phase of the carrier wave constituting the information or signal transmitted from the second device 2 to the first device 1 and the phase of the signal oscillated by the oscillator 13 of the first device 1 when the information or signal is received by the first device 1 is defined as ΔΦ Ｍ Then, the phase difference ΔΦ Ｓ and phase difference ΔΦ Ｍ From the arithmetic mean of these, the phase difference ΔΦ caused by the signal propagating between the first device 1 and the second device 2 is Ｐ That is, it is possible to calculate ΔΦ using the formula (1): Ｐ = 1 / 2 × (ΔΦ Ｓ +ΔΦ Ｍ ) and the phase difference ΔΦ Ｐ can be calculated.

[0054] The phase difference between the first device 1 and the second device 2 is ΔΦ Ｃ Then, the equation (2): ΔΦ Ｍ =ΔΦ Ｐ + (-ΔΦ Ｃ ) holds, so the phase shift ΔΦ Ｃ is the phase difference ΔΦ Ｐ from the phase difference ΔΦ Ｍ That is, it can be calculated by subtracting ΔΦ Ｃ = 1 / 2 × (ΔΦ Ｓ -ΔΦ Ｍ ) causes a phase shift ΔΦＣ In step S15, the phase shift between the first device 1 and the second device 2 is calculated using equation (3).

[0055] Here, the phase shift ΔΦ Ｃ was calculated using equation (3), but the phase shift ΔΦ Ｃ However, it may be further subtracted by 2π or 4π, i.e., 2nπ. n can be 0 or a positive integer. Therefore, the propagation time T Ｐ Based on the time difference between the first device 1 and the second device 2, it is possible to determine whether n is 0, 1, or 2 (i.e., the phase difference ΔΦ obtained from equation (3)). Ｃ It is also possible to determine whether the value obtained by further subtracting 2nπ from the phase shift is the original phase shift, or whether the value without the subtraction is the original phase shift.

[0056] The signal transmitted from the first device 1 to the second device 2 and the signal transmitted from the second device 2 to the first device 1 may start with an output of any value other than 0 at the start of transmission. In such a case, the phase and transmission time at the start of transmission are measured, and the phase shift ΔΦ Ｃ It is necessary to correct ΔΦ by always keeping the phase constant at the start of transmission and transmitting at a predetermined time, and then measuring the phase at the start of transmission and the transmission time. Ｃ This makes it possible to omit processing such as correcting the

[0057] In the second device 2, the calculated phase shift ΔΦ Ｃ Based on this, the phase of the signal generated by the oscillator 23 of the second device 2 is corrected so as to be synchronized with the signal generated by the oscillator 13 of the first device 1 (step S16). The phase correction in step S16 is controlled and executed by the control unit 21. The phase shift of the oscillator 23 of the second device 2 occurs due to the influence of the environment surrounding the second device 2. By periodically performing synchronization processing in this manner, the clock 22a of the second device 2 can be made to keep time with high accuracy.

[0058] Next, the first device 1 calculates the time difference between the first device 1 and the second device 2 based on the time when the information or signal was transmitted from the first device 1 to the second device 2, the time when the information or signal was transmitted from the second device 2 to the first device 1, the time when the information or signal was transmitted from the first device 1 and received and clocked by the second device 2, and the time when the information or signal was transmitted from the second device 2 and received and clocked by the first device 1 (step S17).

[0059] The time when information or a signal is transmitted from the first device 1 to the second device 2 is the time when the information is transmitted in step S1. Information about this time is transmitted from the first device 1 to the second device 2 in step S13. The time when information or a signal is transmitted from the second device 2 to the first device 1 is the time when the information or signal is transmitted in step S7. The information about this time is stored by the second device 2 in step S9. Next, the time when the information or signal is transmitted from the first device 1 and received and clocked by the second device 2 is the time when the information is received in step S4. The information about this time is clocked by the second device 2 in step S5 and stored in step S6. The time when the information or signal is transmitted from the second device 2 and received and clocked by the first device 1 is the time when the information or signal is received in step S10. The information about this time is clocked in step S11 and transmitted from the first device 1 to the second device 2 in step S13.

[0060] The time when the information or signal is transmitted from the first device 1 to the second device 2 is T Ｍ and the time when the second device 2 transmits information or a signal to the first device 1 is defined as T Ｓ The time when the second device 2 receives the information or signal transmitted from the first device 1 is defined as T ＭＳ Furthermore, the time when the information or signal is transmitted from the second device 2 and received by the first device 1 is defined as T ＳＭ Then, the time difference between the first device 1 and the second device 2 is expressed by the following equation (4): T Ｌ = 1 / 2 × ((T ＳＭ -T Ｓ )-(T ＭＳ -T Ｍ)) In step S17, the time difference between the first device 1 and the second device 2 is calculated using equation (4). Based on the calculated time difference, the second device 2 corrects the time on the second device 2 so that it is synchronized with the time on the first device 1 (step S18).

[0061] Next, the distance between the first device 1 and the second device 2 is calculated (step S19). In step S19, the distance between the first device 1 and the second device 2 can be calculated by calculating the propagation time of the information or signal between the first device 1 and the second device 2 based on the substantial difference between the time when the first device 1 transmits the information or signal and the time when the second device 2 receives the information or signal, and multiplying the propagation time by the propagation speed of the information or signal (e.g., the speed of light). The difference between the time when the information or signal is transmitted by the first device 1 and the time when the information or signal is received by the second device 2 can be calculated, for example, based on the time when the information or signal is transmitted from the first device 1 to the second device 2 in step S1 (the time when the information or signal is transmitted from the first device 1 to the second device 2 in step S13) and the time when the information or signal is received from the first device 1 at the second device 2 in step S4, which is the time stored in memory in step S6, and the time difference calculated in step S17.

[0062] In step S19, the distance between the first device 1 and the second device 2 can be calculated by calculating the propagation time of the information or signal between the first device 1 and the second device 2 based on the substantial difference between the time when the second device 2 transmits the information or signal and the time when the first device 1 receives the information or signal, and multiplying the propagation time by the propagation speed of the information or signal (e.g., the speed of light). The difference between the time when the second device 2 transmits the information or signal and the time when the first device 1 receives the information or signal can be calculated based on, for example, the time when the second device 2 transmits the information or signal to the first device 1 in step S7, which is stored in memory in step S9, the time when the first device 1 receives the information or signal in step S10 (transmitted from the first device 1 to the second device 2 in step S13), and the time difference calculated in step S17.

[0063] The distance between the first device 1 and the second device 2 calculated in step S19 is stored in the memory of the control unit 21 of the second device 2 in association with, for example, time information regarding the calculated time and identification information for identifying the first device 1 (or location information of the first device 1) (step S20). Execution of step S20 ends the distance calculation process.

[0064] By executing the processes of steps S1 to S20, it is possible not only to correct the time difference and phase difference between the first device 1 and the second device 2, but also to calculate the distance between the first device 1 and the second device 2. Note that although step S18 corrects the time difference between the first device 1 and the second device 2, it is not necessary to correct the time difference, and it is also possible to calculate the distance between the first device 1 and the second device 2 without correcting the time difference based on the time difference calculated in step S17. Also, although step S16 corrects the phase difference between the first device 1 and the second device 2, it is not necessary to correct the phase difference, and it is also possible to calculate the distance between the first device 1 and the second device 2 without correcting the phase difference.

[0065] In addition, by executing the processing from steps S1 to S20, the time difference and phase difference between the first device 1 and the second device 2 are corrected and the distance between the first device 1 and the second device 2 is calculated, but it is also possible to execute the processing for correcting the time difference between the first device 1 and the second device 2, the processing for correcting the phase difference between the first device 1 and the second device 2, and the processing for calculating the distance between the first device 1 and the second device 2 separately.

[0066] The above-described process of calculating the distance between the first device 1 and the second device 2 can calculate the distance between one second device 2 and each of multiple first devices 1. When specifying the position of the second device 2, as described below, the distance between the first device 1 and the second device 2 is specified for as many first devices 1 as necessary to specify the position. However, even when calculating the distance between one second device 2 and each of multiple first devices 1, the time offset correction process and the phase offset correction process can be performed only with one first device 1, and the time offset correction process and the phase offset correction process can be omitted when communicating with other first devices 1.

[0067] Here, the second device 2 calculates the distance between the first device 1 and the second device 2, but the first device 1 may calculate the distance between the first device 1 and the second device 2 by processing similar to step S19 instead of the second device 2. When the distance is calculated by the first device 1, the distance between the first device 1 and the second device 2 is stored in the memory of the control unit 11 in association with time information regarding the calculated time, etc., and identification information (second device ID) that can identify the second device 2.

[0068] Alternatively, the server device 4, instead of the second device 2, may calculate the distance between the first device 1 and the second device 2 by processing similar to step S19. When the server device 4 calculates the distance, the information necessary for the calculation is received from the first device 1 and / or the second device 2. When the server device 4 calculates the distance, the distance between the first device 1 and the second device 2 is stored in the storage unit 43 of the server device 4 in association with time information regarding the calculated time, etc., identification information (first device ID) that can identify the first device 1 or location information of the first device 1, and identification information (second device ID) that can identify the second device 2.

[0069] [Position Identification Process] Next, the position identification process according to an embodiment of the present invention will be described. Identifying the position of a second device 2 is premised on the fact that the distances between one second device 2 and each of multiple first devices 1 have been calculated in the distance calculation process. For example, if one second device 2 and multiple first devices 1 are located at the same height, i.e., if these devices exist on the same XY plane, the position of the second device 2 (e.g., the XY coordinates of the second device 2) can be identified based on the respective distances between the one second device 2 and the three first devices 1 and the respective positions of the three first devices 1. Therefore, if one second device 2 and multiple first devices 1 are located at the same height, the number of distance data between the first device 1 and the second device 2 required to identify the position is three.

[0070] Furthermore, for example, if one second device 2 and at least one of the multiple first devices 1 are at different heights and do not exist on the same plane, the position of the second device 2 (e.g., the XYZ coordinates or latitude, longitude, and altitude of the second device 2) can be determined based on the respective distances between the one second device 2 and the four first devices 1 and the respective positions of the four first devices 1. Therefore, if one second device 2 and at least one of the multiple first devices 1 are at different heights and do not exist on the same plane, the number of distance data between the first device 1 and the second device 2 required to determine the position is four. In this case, it is preferable that the four first devices 1 are not located on the same plane. For example, it is preferable that the installation height of at least one first device 1 is different from the installation height of the other three first devices 1. In this way, it is possible to determine the three-dimensional position of the second device 2 regardless of its location.

[0071] 7 is a flowchart of a position specifying process according to an embodiment of the present invention. The order of the processes constituting the flowchart is random as long as no contradiction or inconsistency occurs in the process contents.

[0072] 7 can be executed by, for example, the first device 1, the second device 2, or the server device 4. Information regarding the distance between each of the multiple first devices 1 and the second device 2 (the distance calculated in step S19) may be associated with time information regarding the calculated time, identification information (first device ID) of the first device 1 or location information of the first device 1, and identification information (second device ID) of the second device 2, and may be transmitted in advance to the device executing the location specification process and used in the location specification process. Here, an example in which the server device 4 executes the location specification process will be described.

[0073] When the second device 2 transmits information to the server device 4, the communication between the second device 2 and the server device 4 may be via a smart meter installed in a nearby building. The communication between the second device 2 and the server device 4 may be via an optical fiber installed on a transmission tower.

[0074] In the position identification process, the position of the second device 2 is identified based on the distance between each of the multiple first devices 1 and the second device 2 and the positions of these first devices 1 (step S31). The positions of the first devices 1 may be stored in advance in the server device 4. The calculation process for identifying the position of the second device 2 is not particularly limited.

[0075] The identified position of the second device 2 is stored in the storage unit 43 of the server device 4 in association with time information on the calculated time (time information on the time when the distance was calculated or time information on the time when the position was identified), identification information (first device ID) of the first device 1 or location information of the first device 1, and identification information (second device ID) of the second device 2 (step S32). Steps S31 and S32 complete the position identification process.

[0076] It is preferable that the distances between each of the multiple first devices 1 and the second device, which are used to identify the position of the second device 2 in step S31, are calculated at the same time or at similar times (for example, calculated when the propagation times of information or signals between each of the multiple first devices and the second device are measured at the same time or at similar times). Here, the "similar times" are not particularly limited, but are preferably within a predetermined range from time 1. By using the distances between each of the multiple first devices 1 and the second device calculated at the same time or at similar times, a more accurate position at that time can be identified.

[0077] The position of the second device 2 identified in step S31 may be represented by latitude, longitude, and altitude, or may be represented by XYZ coordinates in a predetermined coordinate space.

[0078] Identifying the position of second device 2 identifies the position of surveillance camera 3. If surveillance camera 3 is a 360-degree camera, it is possible to identify the location that the image captured by surveillance camera 3 shows.

[0079] In step S32, the position of the second device 2 is stored in association with time information regarding the calculated time, so that the server device 4 can store information regarding the position of the second device 2 (hereinafter also referred to as the position information of the second device 2) in chronological order.

[0080] It is preferable that the data of the location of the second device stored in step S32 cannot be changed or deleted. For example, the location of the second device may be stored in a WORM (Write Once Read Many) format. Alternatively, for example, the location of the second device may be stored in a blockchain.

[0081] When the first device 1 or the second device 2 executes the position determination process, in step S32, the determined position of the second device 2 may be stored in the memory in the control unit 11 of the first device 1 or in the memory in the control unit 21 of the second device 2.

[0082] [Position Display Processing] Next, the position display processing according to the embodiment of the present invention will be described. According to the system 10, the position of the second device 2 stored in step S32 can be displayed on a map on the administrator terminal 5. Furthermore, if the surveillance camera 3 has one lens and two second devices 2 are installed on one surveillance camera 3, the orientation of the surveillance camera 3 can be displayed on the map.

[0083] 8 is a flowchart illustrating the position display process according to an embodiment of the present invention. The server device 4 determines the orientation of a single surveillance camera 3 based on the positions of the two second devices 2 attached to the surveillance camera 3 stored in step S32 (step S41). The server device 4 stores the determined orientation of the surveillance camera 3 in the storage unit 43 (step S42). The server device 4 transmits the map, the position of the second device 2, and the orientation of the surveillance camera 3 to the administrator terminal 5 (step S43). The administrator terminal 5 receives the map, the position of the second device 2, and the orientation of the surveillance camera 3 (step S44). The administrator terminal 5 displays the position of the second device 2 and the orientation of the surveillance camera 3 on the map (step S45). Steps S41 to S45 complete the position display process.

[0084] The orientation of the surveillance camera 3 in step S41 may refer to the orientation of the visual axis of the surveillance camera 3. Here, the orientation of the visual axis of the surveillance camera 3 may refer to the orientation starting from the lens of the surveillance camera 3 toward the subject being photographed by the surveillance camera 3. Note that the visual axis of the surveillance camera 3 may correspond to the optical axis of the surveillance camera 3.

[0085] The method for identifying the orientation of the surveillance camera 3 in step S41 is not particularly limited and can be designed as appropriate. For example, the orientation of the surveillance camera 3 may be identified by identifying a vector corresponding to a line segment connecting two second devices 2 (hereinafter also referred to as a second-device-2 vector). The orientation of the second-device-2 vector may be from the rear to the front of the surveillance camera 3 (i.e., the direction in which the lens of the surveillance camera 3 is facing). To be able to identify the orientation of the second-device-2 vector, the server device 4 preferably stores information regarding which of the two second devices 2 attached to the surveillance camera 3 is attached closest to the lens. The server device 4 can identify a vector pointing from the position of the second device 2 having the second device ID farther from the lens to the position of the second device 2 having the second device ID closer to the lens.

[0086] By calculating the distance between each of the multiple first devices 1 and one of the second devices 2, calculating the distance between each of the multiple first devices 1 and the other of the second devices 2, and identifying the position of one of the second devices 2 and the position of the other of the second devices 2, it is possible to identify the vector between the second devices 2 based on the position of one of the second devices 2 and the position of the other of the second devices 2. By storing in the server device 4 the relationship between the orientation of the vector between the second devices 2 and the orientation of the surveillance camera 3 when two second devices 2 are attached to the surveillance camera 3, it is possible to identify the orientation of the surveillance camera 3 based on the orientation of the vector between the second devices 2 identified in step S41. It is preferable that the relationship between the orientation of the vector between the second devices 2 and the orientation of the surveillance camera 3 when two second devices 2 are attached to the surveillance camera 3 be stored in association with the surveillance camera ID of the surveillance camera 3.

[0087] Two second devices 2 are preferably provided on one surveillance camera 3 so that a vector corresponding to a line segment connecting the two second devices 2 is parallel to a vector corresponding to the visual axis of the surveillance camera 3. In this case, the direction of the vector between the second devices 2 is the same as the direction of the surveillance camera 3. When three or more second devices 2 are provided on one surveillance camera 3, it is sufficient that the vector corresponding to the line segment connecting any two of the three or more second devices 2 is provided so as to be parallel to a vector corresponding to the visual axis of the one surveillance camera 3.

[0088] In addition, when two second devices 2 are attached to a surveillance camera 3, the server device 4 stores the relationship between the position of one or more of the two second devices 2 and the visual axis of the surveillance camera 3, so that the visual axis of the surveillance camera 3 can be identified based on the direction of the vector between the second devices 2 and the position of the second devices 2.

[0089] By identifying the orientation of the surveillance camera 3, it is possible to identify the direction in which the surveillance camera 3 was facing when capturing an image. In other words, it is possible to identify the location that the image captured by the surveillance camera 3 depicts. The orientation of the surveillance camera 3 may be identified in the second device 2. In this case, the orientation of the surveillance camera 3 may be transmitted from the second device 2 to the server device 4.

[0090] In step S42, the server device 4 stores the orientation of the surveillance camera 3 in association with the surveillance camera ID, the positions of the two second devices 2 provided on the surveillance camera 3, and the time at which the positions of the second devices 2 were identified. That is, the orientation of the surveillance camera 3 is stored in chronological order in the server device 4. The server device 4 may also store images captured by the surveillance camera 3 in association with the surveillance camera ID and the time at which the positions of the second devices 2 were identified.

[0091] When the server device 4 stores the surveillance camera ID, the positions of the two second devices 2 provided on the surveillance camera 3, and the orientation of the surveillance camera 3 and / or the captured images in association with the time at which the positions of the second devices 2 were identified, it is possible to make it impossible to change or delete the data for this information. The file storing this information may be stored, for example, using a WORM (Write Once Read Many) method. Alternatively, for example, the file storing this information may be stored in a blockchain.

[0092] The transmission of information in step S43 may be executed in response to a display request from the administrator terminal 5. Furthermore, the location of the map, the type of map, and / or the position of the second device 2 to be transmitted in step S43 may be selectable by input to the administrator terminal 5. For example, the administrator may input the name or address of a location where the administrator wants to check the orientation of the surveillance camera 3, and transmit a display request to the server device 4, using the administrator terminal 5. Furthermore, for example, the administrator may select the type of map to be displayed (e.g., a map represented by an illustration, a map represented by an aerial photograph, etc.), and transmit a display request to the server device 4, using the administrator terminal 5.

[0093] In step S45, the administrator terminal 5 displays the position of the second device 2 and the orientation of the surveillance camera 3 received in step S44 on the map received in step S44. The manner in which the position of the second device 2 and the orientation of the surveillance camera 3 are displayed on the map is not particularly limited and can be designed as appropriate. For example, an execution screen such as that shown in FIG. 9 may be displayed on the display screen of the administrator terminal 5.

[0094] 9 is a diagram illustrating an example of an execution screen according to an embodiment of the present invention. On the execution screen 100, an icon 102 (hereinafter also referred to as the "front second device icon 102") corresponding to the position of the second device 2 provided in front of the surveillance camera 3 and an icon 103 (hereinafter also referred to as the "rear second device icon 103") corresponding to the position of the second device 2 provided behind the surveillance camera 3 are displayed on a map 101. Also, on the execution screen 100, an icon 104 (hereinafter also referred to as the "camera icon 104") corresponding to the surveillance camera 3 is displayed so as to overlap the front second device icon 102 and the rear second device icon 103. An area 105 (captured area 105) captured by the surveillance camera 3 is displayed on an extension of the lens of the camera icon 104. Also, buildings 106 (106a to 106c) are displayed on the map 101.

[0095] On the execution screen 100, the orientation of the surveillance camera 3 is indicated by the orientation of the camera icon 104. Note that a protrusion displayed near the front second device icon 102 indicates the orientation of the lens of the camera icon 104. The orientation of the surveillance camera 3 may be displayed in such a way that the administrator can grasp the orientation of the surveillance camera 3. For example, the orientation of the surveillance camera 3 may be indicated by the orientation of the camera icon 104 as shown in FIG. 9 , or may be indicated by an arrow mark or the like.

[0096] 9, it is preferable to attach one second device 2 to one surveillance camera 3 in front of the surveillance camera 3 and the other second device 2 to the rear of the surveillance camera 3. By providing one second device 2 in front of the surveillance camera 3 and one second device 2 in rear of the surveillance camera 3, it becomes easy to grasp the orientation of the surveillance camera 3 when the position of the second device 2 is displayed on the map 101.

[0097] The shooting range 105 is not particularly limited as long as it serves as a guide for the range captured by the surveillance camera 3. Areas of different shapes and / or sizes may be displayed as the shooting range 105 depending on the angle of view of the lens of the surveillance camera 3 and / or the distance at which the surveillance camera 3 is capturing images. The angle of view of the lens of the surveillance camera 3 and / or the distance at which the surveillance camera 3 is capturing images may be stored in the server device 4 in association with the surveillance camera ID.

[0098] 9 is displayed, the administrator can see that the building 106a is being photographed by two surveillance cameras 3, but the building 106b is not being photographed by any surveillance camera 3. Therefore, the administrator can make decisions such as changing the installation locations of the surveillance cameras 3, changing the orientation of the surveillance cameras 3, or moving the surveillance cameras 3 so that all of the buildings 106 can be photographed.

[0099] 9 is displayed, the administrator can see that no surveillance cameras 3 are installed in the lower right area of ​​the map 101. Therefore, the administrator can make a decision to change the installation locations of the surveillance cameras 3, change the orientation of the surveillance cameras 3, or move the surveillance cameras 3 so that the area displayed on the map 101 can be evenly photographed.

[0100] Even if the surveillance camera 3 does not have a swivel function, there is a possibility that the direction of the surveillance camera 3 may be changed intentionally by a person, or may be changed by a collision with an animal or flying object, or by a strong wind, etc. If the direction of the surveillance camera 3 is not in the specified direction, the administrator can decide to correct the direction of the surveillance camera 3 so that it is in the specified direction.

[0101] Returning to the explanation of Fig. 9 , the date and time 107 (hereinafter also referred to as the display date and time 107) stored in association with the position of the displayed second device 2 and the orientation of the surveillance camera 3 is displayed in the lower right corner of the map 101 on the execution screen 100. In Fig. 9 , the date and time displayed as the display date and time 107 is "January 25, 2024, 13:30:00." Therefore, the administrator can understand that the map 101 displays the position of the second device 2 and the orientation of the surveillance camera 3 at January 25, 2024, 13:30:00.

[0102] A field 108 (hereinafter also referred to as a date and time input field 108) for inputting the date and time corresponding to the position of the second device 2 and the orientation of the surveillance camera 3 that the administrator wants to display is displayed in the upper right portion of the map 101 on the execution screen 100. On the administrator terminal 5, the administrator can input the date and time at which the administrator wants to check the position of the second device 2 and the orientation of the surveillance camera 3 in the date and time input field 108 and press a display button 109 to display on the map 101 the position of the second device 2 and the orientation of the surveillance camera 3 that are stored in association with the input date and time. The date and time input field 108 may be one that allows the date and time to be input using a pull-down menu, or may be one that allows the date and time to be input by typing numbers and / or letters.

[0103] A play button 110, a rewind button 111, and a fast-forward button 112 are displayed in the lower left corner of the map 101 on the execution screen 100. As described above, the server device 4 stores the position of the second device 2 and the orientation of the surveillance camera 3 in chronological order. When the play button 110 is pressed on the administrator terminal 5, the position of the second device 2 and the orientation of the surveillance camera 3 may be displayed continuously in chronological order on the map 101. Furthermore, when the rewind button 111 is pressed on the administrator terminal 5, the position of the second device 2 and the orientation of the surveillance camera 3 at a date and time going back a predetermined time may be displayed on the map 101. Furthermore, when the fast-forward button 112 is pressed on the administrator terminal 5, the position of the second device 2 and the orientation of the surveillance camera 3 at a date and time going forward a predetermined time may be displayed on the map 101.

[0104] It is not necessary to execute steps S41 and S42 when the surveillance camera 3 is equipped with one second device 2. In this case, in step S43, the map and the position of the second device 2 identified in step S31 may be transmitted to the administrator terminal 5, and the position of the second device 2 may be displayed on the map 101.

[0105] In this way, a system can be provided for locating the position of a surveillance camera by comprising a plurality of first devices, a surveillance camera, and a second device attached to the surveillance camera, a distance calculation means for calculating the distance between each of the plurality of first devices and the second device based on the propagation time of information or signals between each of the plurality of first devices and the second device, and a position determination means for determining the position of the second device based on the calculated distance between each of the plurality of first devices and the second device.

[0106] In this way, one surveillance camera is provided with at least two second devices, a distance calculation means calculates the distance between each of the multiple first devices and one of the second devices, and calculates the distance between each of the multiple first devices and the other of the second devices, a position identification means identifies the position of one of the second devices and the position of the other of the second devices, and the system is provided with an orientation identification means that identifies the orientation of the surveillance camera based on the position of one of the second devices and the position of the other of the second devices, thereby making it possible to identify the orientation of the surveillance camera.

[0107] Furthermore, in this way, in the system, one surveillance camera is provided with at least two second devices, and the two second devices are arranged so that the vector corresponding to the line segment connecting the two second devices is parallel to the vector corresponding to the visual axis of one surveillance camera, making it easy to identify the orientation of the surveillance camera.

[0108] Furthermore, since the system is equipped with a storage means for storing the location of the identified second device and the data for the location stored in the storage means cannot be changed or deleted, the location of the surveillance camera can be made more persuasive as evidence.

[0109] Furthermore, by providing the system with a display control means for controlling the display of the identified location on a map, it becomes easier to grasp the location of the surveillance camera.

[0110] Furthermore, since the distance calculation means calculates the distance between the first device and the second device based on the time difference between the internal clock of the first device and the internal clock of the second device, a more accurate distance can be calculated.

[0111] Furthermore, by having the system communicate between one first device and one second device in this way, it is possible to synchronize the time of the second device with the time of the first device by providing a time difference calculation means for calculating the time difference between one first device and one second device, and a time correction means for correcting the time of the second device based on the calculated time difference.

[0112] Furthermore, by having the system communicate between one first device and one second device, and being provided with a phase shift calculation means for calculating the phase shift of the clocks between one first device and one second device, and a phase correction means for correcting the phase in the second device based on the calculated phase shift, the phase of the second device can be synchronized with the phase of the first device.

[0113] Furthermore, since the surveillance camera is equipped with a second device that can communicate with multiple first devices, the location of the surveillance camera can be identified by identifying the location of the second device.

[0114] Furthermore, since the surveillance camera is equipped with at least two second devices and is arranged so that the vector corresponding to the line segment connecting the two second devices is parallel to the vector corresponding to the visual axis of one surveillance camera, it becomes easy to identify the orientation of the surveillance camera.

[0115] Other Embodiments The object whose orientation is determined using at least two second devices is not limited to a surveillance camera. For example, it is also possible to determine the orientation of objects such as moving objects (vehicles, ships, agricultural machinery, drones, automatic cleaning robots, automatic food delivery robots, etc.), solar panels, telescopes, antennas, weather vanes, and thumb turns used to open and close doors. Note that a "moving object" may be anything that can be moved by human operation and / or automatically. Furthermore, it is also possible to measure the inclination of an object using at least two second devices. For example, it is also possible to measure the level (inclination) of a building or the inclination of a road when constructing a building.

[0116] In this case, the "surveillance camera" in FIGS. 1 and 9 can be replaced with "object." Furthermore, the hardware configurations of the first device, second device, server device, and administrator terminal shown in FIGS. 2 to 5 can be similar to those described above. The above descriptions can be used to the extent necessary for the distance calculation process and position identification process shown in FIGS. 6 and 7 . That is, after correcting the phase shift and time shift of the second device provided on the object, the distance between the first device and the second device can be calculated and the position of the second device can be identified. Furthermore, the "direction of the surveillance camera" in steps S41 to S45 of the position display process in FIG. 8 can be replaced with the "direction of the object."

[0117] In other words, the present invention may be a system comprising a plurality of first devices, an object, and at least two second devices provided on the object, the system comprising: a distance calculation means for calculating a distance between each of the plurality of first devices and the second device based on the propagation time of information or signals between each of the plurality of first devices and the second device; and a position determination means for determining a position of the second device based on the calculated distance between each of the plurality of first devices and the second device, wherein the distance calculation means calculates the distance between each of the plurality of first devices and one of the second devices, and calculates the distance between each of the plurality of first devices and the other of the second devices, the position determination means determines the position of one of the second devices and the position of the other of the second devices, respectively, and further comprising an orientation determination means for determining the orientation and / or inclination of the object based on the position of one of the second devices and the position of the other of the second devices.

[0118] REFERENCE SIGNS LIST 1 First device 2 Second device 3 Surveillance camera 4 Server device 5 Administrator terminal 6 Communication network 10 System 11 Control unit 12 RF chip 12a Clock 12b Phase detector 13 Oscillator 21 Control unit 22 RF chip 22a Clock 22b Phase detector 23 Oscillator 41 Control unit 42 RAM 43 Storage unit 44 Communication interface 51 Control unit 52 RAM 53 Storage unit 54 Input unit 55 Display unit 56 Communication interface 100 Execution screen 101 Map 102 Front second device icon 103 Rear second device icon 104 Camera icon 105 Shooting range 106 Building 107 Display date and time 108 Date and time input field 109 Display button 110 Play button 111 Rewind button 112 Fast forward button

Claims

1. A system comprising a plurality of first devices, a surveillance camera, and a second device attached to the surveillance camera, the system comprising: a distance calculation means for calculating the distance between each of the plurality of first devices and the second device based on the propagation time of information or signals between each of the plurality of first devices and the second device; and a location determination means for determining the location of the second device based on the calculated distance between each of the plurality of first devices and the second device.

2. The system according to claim 1, wherein one surveillance camera is equipped with at least two second devices, a distance calculation means calculates the distance between each of the plurality of first devices and one of the second devices, and calculates the distance between each of the plurality of first devices and the other of the second devices, a position determination means determines the position of one of the second devices and the position of the other of the second devices, and further comprises an orientation determination means for determining the orientation of the surveillance camera based on the position of one of the second devices and the position of the other of the second devices.

3. A system as described in claim 1 or 2, wherein at least two second devices are provided for one surveillance camera, and the two second devices are provided so that a vector corresponding to a line segment connecting the two second devices is parallel to a vector corresponding to the visual axis of one surveillance camera.

4. The system according to claim 1 or 2, further comprising: a storage means for storing the identified location of the second device; and the data for the location stored in the storage means cannot be changed or deleted.

5. The system according to claim 1 or 2, further comprising: a display control means for controlling the display of the identified position on a map.

6. A system according to claim 1 or 2, wherein the distance calculation means calculates the distance between the first device and the second device based on the time difference between the internal clock of the first device and the internal clock of the second device.

7. A system as claimed in claim 1 or 2, comprising: a time difference calculation means for calculating the time difference between a first device and a second device by communicating between the first device and the second device; and a time correction means for correcting the time on the second device based on the calculated time difference.

8. A system according to claim 1 or 2, comprising: a phase shift calculation means for calculating a phase shift between the clocks of one first device and one second device by communicating between the first device and the second device; and a phase correction means for correcting the phase of the second device based on the calculated phase shift.

9. A method executed in a system comprising a plurality of first devices, a surveillance camera, and a second device attached to the surveillance camera, the method comprising: a distance calculation step of calculating the distance between each of the plurality of first devices and the second device based on the propagation time of information or signals between each of the plurality of first devices and the second device; and a location determination step of determining the location of the second device based on the calculated distance between each of the plurality of first devices and the second device.

10. A surveillance camera equipped with a second device capable of communicating with a plurality of first devices.

11. A surveillance camera according to claim 10, wherein at least two second devices are provided, and the vector corresponding to the line segment connecting the two second devices is arranged so as to be parallel to the vector corresponding to the visual axis of one surveillance camera.

12. A system comprising: a plurality of first devices; an object; and at least two second devices provided on the object, the system comprising: distance calculation means for calculating a distance between each of the plurality of first devices and the second devices based on the propagation time of information or signals between each of the plurality of first devices and the second devices; position identification means for identifying a position of the second devices based on the calculated distances between each of the plurality of first devices and one of the second devices, wherein the distance calculation means calculates the distance between each of the plurality of first devices and one of the second devices, and calculates the distance between each of the plurality of first devices and the other of the second devices; position identification means for identifying the position of one of the second devices and the position of the other of the second devices, respectively; and orientation identification means for identifying the orientation and / or tilt of the object based on the position of one of the second devices and the position of the other of the second devices.

13. The system according to claim 12, wherein the object is a moving object, a solar panel, a telescope, an antenna, a weather vane, a thumb turn, a building, and / or a road.

14. A method executed in a system comprising a plurality of first devices, an object, and at least two second devices provided on the object, the method comprising: a distance calculation step of calculating a distance between each of the plurality of first devices and the second device based on the propagation time of information or signals between each of the plurality of first devices and the second device; and a position determination step of determining a position of the second device based on the calculated distances between each of the plurality of first devices and one of the second devices, wherein the distance calculation step calculates a distance between each of the plurality of first devices and one of the second devices, and calculates a distance between each of the plurality of first devices and the other of the second devices, the position determination step determines the position of one of the second devices and the position of the other of the second devices, respectively; and an orientation determination step of determining the orientation and / or tilt of the object based on the position of one of the second devices and the position of the other of the second devices.

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