Monitoring system, monitoring device, monitoring method, and program

Abstract

Provided is a monitoring system that includes: a detection position acquisition means that acquires a first detection position at which vibration was detected at a first optical fiber cable and a second detection position at which vibration was detected at a second optical fiber cable that is spaced at an interval from the first optical fiber cable; and a crossing angle estimation means that estimates the crossing angle at which a mobile body has crossed the first optical fiber cable and the second optical fiber cable on the basis of the first detection position and the second detection position.

Description

Monitoring System, Monitoring Device, Monitoring Method, and Program

[0001] The present disclosure relates to a monitoring system, a monitoring device, a monitoring method, and a program.

[0002] There are many cases of smuggling drugs and the like across borders. In particular, there are regions without physical barriers such as fences or walls at the border in some countries, such as desert areas far from inhabited areas, and it is required to grasp the actual situation of border crossings in such regions.

[0003] While the monitoring targets are moving objects such as people and vehicles, the monitoring area is a wide area spanning hundreds of kilometers. There are extremely limited ways to monitor moving objects at a realistic cost while covering such a wide area.

[0004] For example, low-orbit satellites equipped with visible light or near / far infrared cameras can detect moving objects in a wide area, but the satellites do not always stay above the border, and the monitoring timing is limited.

[0005] As an effective method, distributed fiber optic sensing technology can be cited. In distributed fiber optic sensing technology, by measuring the backscattered light of the optical fiber, strain, temperature, pressure, and vibration at any position can be detected in a section along the optical fiber that extends for dozens of kilometers.

[0006] That is, by providing an optical fiber sensor including an optical fiber along the border fence or wall, a section of dozens of kilometers of the border can be monitored without power supply. In this way, when there is a fence or wall at the border, contraband is delivered near the fence or wall, so the moving object will stay near the fence or wall for a certain period of time, and it is expected to detect the moving object with high reliability.

[0007] On the other hand, if there are no physical barriers such as fences or walls along the border, moving objects will cross the border in a short amount of time. Even if fiber optic sensors are installed along the border, it will be difficult to distinguish the detection results of moving objects from noise. Furthermore, the speed of the moving object will not be known, making it impossible to obtain sufficient information such as whether the object is a person or horse, or a high-speed moving object such as a car.

[0008] Patent Document 1 discloses a technology for detecting people walking unsteadily on a train platform by installing multiple optical fibers on the platform.

[0009] Japanese Patent Publication No. 2024-092385

[0010] To track a moving object that has crossed a border, especially in deserts or other areas without roads, it is not enough to simply detect that the object has crossed the border; it is also necessary to determine the angle at which the object crossed the border.

[0011] Therefore, the purpose of this disclosure is to provide a technology for estimating the crossing angle when a moving object crosses an optical fiber cable.

[0012] A monitoring system is provided, which includes: a detection position acquisition means for acquiring a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable; and a crossing angle estimation means for estimating the crossing angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position.

[0013] A monitoring device is provided, which includes: a detection position acquisition means for acquiring a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable; and a crossing angle estimation means for estimating the crossing angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position.

[0014] A monitoring method is provided in which a computer acquires a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable, and estimates the crossing angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first and second detection positions.

[0015] A program is provided that causes a computer to function as: a detection position acquisition means that acquires a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable; and a crossing angle estimation means that estimates the crossing angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position.

[0016] According to this disclosure, it is possible to estimate the crossing angle when a moving object crosses an optical fiber cable.

[0017] This is a block diagram of the monitoring system. This is the operation flow of the monitoring system. This is a schematic diagram of the monitoring system. This is a block diagram of the monitoring device. This is a diagram showing an example of an overlaid image. This is the operation flow of the monitoring device. This is a diagram showing an example of an overlaid image. This is a schematic diagram of the monitoring system. This is a schematic diagram of the monitoring system. This is a block diagram illustrating the hardware configuration of a computer.

[0018] (Summary of this disclosure) First, an overview of this disclosure will be provided. Figure 1 is a block diagram of the monitoring system 100. As shown in Figure 1, the monitoring system 100 includes a detection position acquisition means 101 and a cross-sectional angle estimation means 102.

[0019] The detection position acquisition means 101 acquires a first detection position where vibration is detected in the first optical fiber cable, and a second detection position where vibration is detected in the second optical fiber cable, which is positioned at a distance from the first optical fiber cable.

[0020] The cross-sectional angle estimation means 102 estimates the cross-sectional angle when a moving object crosses the first optical fiber cable and the second optical fiber cable, based on the first detection position and the second detection position.

[0021] Next, the operation of the monitoring system 100 will be explained. Figure 2 shows the operation flow of the monitoring system 100. As shown in Figure 2, first, the detection position acquisition means 101 acquires a first detection position where vibration is detected in the first optical fiber cable, and a second detection position where vibration is detected in the second optical fiber cable, which is spaced apart from the first optical fiber cable (S101). Next, the cross-sectional angle estimation means 102 estimates the cross-sectional angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position (S102).

[0022] With the above configuration, it is possible to estimate the cross-sectional angle at which a moving object crosses the optical fiber cable.

[0023] The present invention will be described below through embodiments of the invention, but the invention claimed is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential as means of solving the problem. For clarity of explanation, the following descriptions and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are denoted by the same reference numerals, and redundant explanations have been omitted where necessary.

[0024] In the following embodiments, the description will be divided into multiple sections or embodiments where necessary for convenience. Unless otherwise specified, these are not unrelated, and one may be a modification, application, detailed explanation, or supplementary explanation of part or all of the other. Furthermore, in the following embodiments, when referring to the number of elements (including number, numerical value, quantity, and range), unless otherwise specified or clearly limited to a specific number in principle, it is not limited to that specific number, and may be greater than or less than that number.

[0025] Furthermore, in the following embodiments, the components (including operation steps, etc.) are not necessarily essential unless specifically stated or considered to be clearly essential in principle. Similarly, in the following embodiments, when referring to the shape or positional relationship of components, etc., it shall include those substantially similar to or resembling their shape, etc., unless specifically stated or considered to be not in principle. The same applies to the numbers, etc. (including the number of items, numerical values, quantities, and ranges) mentioned above.

[0026] (First Embodiment) Next, a first embodiment of the present disclosure will be described. Figure 3 is a schematic diagram of the monitoring system 1.

[0027] As shown in Figure 3, in this embodiment, the monitoring system 1 includes an optical fiber sensor 3 positioned along the border 2 and a monitoring device 4.

[0028] In this embodiment, the border 2 is located in a desert area, for example. No barriers such as fences or walls are provided along the border 2. However, this is not limited to this, and barriers may be provided along the border 2.

[0029] The optical fiber sensor 3 is installed to extend along the border 2. The optical fiber sensor 3 is composed of a plurality of optical fiber cables 5. In this embodiment, the plurality of optical fiber cables 5 include a first optical fiber cable 5a and a second optical fiber cable 5b. The first optical fiber cable 5a and the second optical fiber cable 5b are spaced apart. The first optical fiber cable 5a and the second optical fiber cable 5b extend parallel to each other. That is, the distance D between the first optical fiber cable 5a and the second optical fiber cable 5b is constant. The first optical fiber cable 5a is closer to the border 2 than the second optical fiber cable 5b.

[0030] In this embodiment, for the sake of explanation, it is assumed that the vehicle 6 crosses the border 2 and the optical fiber sensor 3 in the order described. Therefore, after crossing the border 2, the vehicle 6 first crosses the first optical fiber cable 5a, and then crosses the second optical fiber cable 5b. If there is no barrier or road along the border 2, the vehicle 6 travels in a straight line connecting the starting point and the destination. Therefore, the vehicle 6 typically crosses the border 2 and the optical fiber sensor 3 diagonally. That is, the crossing angle θ, which is the angle between the direction of travel of the vehicle 6 and the longitudinal direction of the optical fiber sensor 3, satisfies the relationship 0 < θ < 90. Figure 3 shows both the crossing point 7a where the vehicle 6 crosses the first optical fiber cable 5a and the crossing point 7b where the vehicle 6 crosses the second optical fiber cable 5b. The vehicle 6 is one specific example of a moving object. The moving object is not limited to the vehicle 6, but may be a person traveling on foot or on horseback, or an unmanned aerial vehicle such as a drone.

[0031] The monitoring device 4 is connected to the optical fiber sensor 3. The monitoring device 4 uses the optical fiber sensor 3 to detect vehicles 6 crossing the optical fiber sensor 3. Specifically, the monitoring device 4 uses the optical fiber sensor 3 to detect or estimate the crossing position, crossing angle θ, and crossing speed of vehicles 6 crossing the optical fiber sensor 3. The monitoring device 4 is implemented by a single device. However, it is not limited to this, and the monitoring device 4 may be implemented by distributed processing using multiple devices.

[0032] Figure 4 shows a block diagram of the monitoring device 4. As shown in Figure 4, the monitoring device 4 includes a detection data storage unit 10, a map data storage unit 11, a detection position acquisition unit 12, a cross-sectional angle estimation unit 13, a cross-sectional speed estimation unit 14, a movement estimation unit 15, and an output unit 16.

[0033] The detection data storage unit 10 stores the detection results obtained by the detection position acquisition unit 12.

[0034] The map data storage unit 11 stores map data. The map data shows the locations of multiple settlements, roads, national borders, fiber optic sensors 3, and other locations in a geographic coordinate system. A settlement includes cities, towns, and villages. In the map data, roads, national borders, and fiber optic sensors 3 are typically defined by multiple nodes and multiple links connecting those nodes.

[0035] The detection position acquisition unit 12 detects a vehicle 6 crossing the optical fiber sensor 3 by using the optical fiber sensor 3 as a distributed optical fiber sensor. The detection position acquisition unit 12 detects vibrations occurring at any position along the longitudinal direction of the first optical fiber cable 5a. The detection position acquisition unit 12 stores the detected position and time of the vibration in the detection data storage unit 10. Similarly, the detection position acquisition unit 12 detects vibrations occurring at any position along the longitudinal direction of the second optical fiber cable 5b. The detection position acquisition unit 12 stores the detected position and time of the vibration in the detection data storage unit 10.

[0036] The crossing angle estimation unit 13 estimates the crossing angle θ when the vehicle 6 crosses the first optical fiber cable 5a and the second optical fiber cable 5b, based on the detection position in the first optical fiber cable 5a and the detection position in the second optical fiber cable 5b. Specifically, in Figure 3, the detection position in the first optical fiber cable 5a corresponds to the crossing point 7a, and the detection position in the second optical fiber cable 5b corresponds to the crossing point 7b. As shown in Figure 3, the detection position in the first optical fiber cable 5a is represented by the distance L1 between the detection position and the monitoring device 4. Similarly, the detection position in the second optical fiber cable 5b is represented by the distance L2 between the detection position and the monitoring device 4. The crossing angle estimation unit 13 then estimates the crossing angle θ using trigonometric functions based on the difference ΔL between distance L1 and distance L2 and the aforementioned distance D. As an example, as shown in Figure 3, if the angle between the orthogonal direction perpendicular to the longitudinal direction of the second optical fiber cable 5b and the direction of travel of the vehicle 6 is defined as the transverse angle θ, the transverse angle estimation unit 13 can determine the transverse angle θ using arctan(ΔL / D).

[0037] The crossing speed estimation unit 14 estimates the crossing speed v when the vehicle 6 crosses the first optical fiber cable 5a and the second optical fiber cable 5b, based on the detection position and time in the first optical fiber cable 5a and the detection position and time in the second optical fiber cable 5b. Specifically, the crossing speed v can be estimated by the following formula. However, in the following formula, t ａ is the detection time in the first optical fiber cable 5a, and t ｂ This is the detection time in the second optical fiber cable 5b.

[0038] The movement estimation unit 15 estimates the movement of the vehicle 6 after it has crossed the first optical fiber cable 5a and the second optical fiber cable 5b, based on the estimation results from the crossing angle estimation unit 13 and the crossing speed estimation unit 14. The estimation result from the crossing angle estimation unit 13 refers to the crossing angle θ. The estimation result from the crossing speed estimation unit 14 refers to the crossing speed v. The movement estimation unit 15 estimates the movement of the vehicle 6, for example, the azimuth angle of the vehicle 6's movement, the vehicle 6's departure point, the vehicle 6's destination, and the time of arrival of the vehicle 6 at its destination. The movement estimation unit 15 estimates the movement of the vehicle 6, which may be at least one or more of the azimuth angle of the vehicle 6's movement, the vehicle 6's departure point, the vehicle 6's destination, and the time of arrival of the vehicle 6 at its destination.

[0039] First, the movement estimation unit 15 calculates the azimuth angle of movement, which is the azimuth angle of vehicle 6's movement when it crosses the optical fiber sensor 3, based on the crossing angle θ and map data. Specifically, the movement estimation unit 15 obtains the longitudinal azimuth angle of the link containing the crossing point 7a of the first optical fiber cable 5a based on the map data, and calculates the azimuth angle of movement of vehicle 6 when it crosses the optical fiber sensor 3 by adding the crossing angle θ to the longitudinal azimuth angle of the link.

[0040] Next, the movement estimation unit 15 calculates the geographic coordinates of the crossing point 7a based on the detection position in the first optical fiber cable 5a and map data. That is, since the detection position in the first optical fiber cable 5a is represented by the distance L1 between the detection position and the monitoring device 4, the geographic coordinates of the crossing point 7a, which is at a distance L1 from the monitoring device 4 along the first optical fiber cable 5a, are calculated based on the map data.

[0041] Next, the movement estimation unit 15 estimates the departure location and the destination of the vehicle 6 based on the geographical coordinates of the crossing point 7a and the movement azimuth angle of the vehicle 6. Specifically, the movement estimation unit 15 assumes that the vehicle 6 moves linearly from the departure location to the destination, and estimates a linear movement trajectory of the vehicle 6 with the crossing point 7a as a passing point based on the movement azimuth angle of the vehicle 6, and extracts settlements existing on the movement trajectory as the departure location and the destination. Among the settlements existing on the movement trajectory, the settlement where the vehicle 6 could have existed before crossing the optical fiber sensor 3 is the departure location, and the settlement that the vehicle 6 could reach after crossing the optical fiber sensor 3 is the destination.

[0042] Further, the movement estimation unit 15 calculates the distance between the crossing point 7a and the destination based on the map data, and estimates the arrival time of the vehicle 6 at the destination by adding the required time obtained by dividing the distance by the crossing speed v to the detection time at the crossing point 7a.

[0043] When the movement estimation unit 15 estimates the departure location, the destination, and the arrival time at the destination of the vehicle 6, typically, it is based on the first optical fiber cable 5a and the crossing point 7a. However, it is not limited to this, and the movement estimation unit 15 may estimate the departure location, the destination, and the arrival time at the destination of the vehicle 6 based on the second optical fiber cable 5b and the crossing point 7b. This is because the crossing point 7a and the crossing point 7b are actually only separated by about several meters.

[0044] The output unit 16 outputs a superimposed image in which the estimation result by the movement estimation unit 15 is superimposed on the map. The output unit 16 may output the superimposed image to a display device included in the monitoring device 4, or may output the superimposed image to an external device connected to the monitoring device 4. FIG. 5 shows an example of the superimposed image M. As shown in FIG. 5, as an example, the map m shown by the map data includes a settlement p, a road q, and a border 2. The output unit 16 determines the magnitude and direction of the movement vector g of the vehicle 6 based on the movement azimuth angle of the vehicle 6 and the crossing speed v of the vehicle 6, and generates a superimposed image M in which the estimation result by the movement estimation unit 15 is superimposed on the map m by drawing the movement vector g on the map m in the form of, for example, a white arrow. The movement vector g of the vehicle 6 is an example of the estimation result by the movement estimation unit 15.

[0045] Further, the output unit 16 generates a superimposed image M in which the estimated result by the movement estimation unit 15 is superimposed on the map m by indicating the destination d estimated by the movement estimation unit 15 with a circle mark and indicating the arrival time at the destination d estimated by the movement estimation unit 15 near the destination d. As a result, it becomes possible to proactively deal with the illegally crossing vehicle 6 by strengthening the monitoring network around the destination d and the like.

[0046] Next, the operation of the monitoring device 4 will be described with reference to FIG. 6. First, the detection position acquisition unit 12 uses the optical fiber sensor 3 as a distributed optical fiber sensor to detect the vehicle 6 crossing the optical fiber sensor 3, and stores the detection position and the detection time in the detection data storage unit 10 (S200). Next, the crossing angle estimation unit 13 estimates the crossing angle θ when the vehicle 6 crosses the first optical fiber cable 5a and the second optical fiber cable 5b based on the detection position in the first optical fiber cable 5a and the detection position in the second optical fiber cable 5b (S210). Next, the crossing speed estimation unit 14 estimates the crossing speed when the vehicle 6 crosses the first optical fiber cable 5a and the second optical fiber cable 5b based on the detection position and the detection time in the first optical fiber cable 5a and the detection position and the detection time in the second optical fiber cable 5b (S220). Next, the movement estimation unit 15 estimates the movement of the vehicle 6 after the vehicle 6 crosses the first optical fiber cable 5a and the second optical fiber cable 5b based on the estimation result by the crossing angle estimation unit 13 and the estimation result by the crossing speed estimation unit 14 (S230). Then, the output unit 16 outputs a superimposed image in which the estimation result by the movement estimation unit 15 is superimposed on the map (S240).

[0047] The first embodiment of the present disclosure has been described above. The above first embodiment has the following features.

[0048] The monitoring device 4 includes a detection position acquisition unit 12 (detection position acquisition means) and a cross-sectional angle estimation unit 13 (cross-sectional angle estimation means). The detection position acquisition unit 12 acquires a first detection position where vibration is detected in the first optical fiber cable 5a, and a second detection position where vibration is detected in the second optical fiber cable 5b, which is spaced apart from the first optical fiber cable 5a. Based on the first and second detection positions, the cross-sectional angle estimation unit 13 estimates the cross-sectional angle θ when the vehicle 6 (moving body) crosses the first optical fiber cable 5a and the second optical fiber cable 5b. With the above configuration, the cross-sectional angle θ when the vehicle 6 crosses the optical fiber sensor 3 can be estimated.

[0049] Furthermore, the first optical fiber cable 5a and the second optical fiber cable 5b are installed parallel to each other. The transverse angle estimation unit 13 estimates the transverse angle θ based on the difference ΔL between the first detection position and the second detection position in the longitudinal direction of the first optical fiber cable 5a, and the distance D between the first optical fiber cable 5a and the second optical fiber cable 5b. With the above configuration, the transverse angle θ can be estimated by a simple calculation.

[0050] Furthermore, the monitoring device 4 also includes a crossing speed estimation unit 14 (crossing speed estimation means). The crossing speed estimation unit 14 estimates the crossing speed v when the vehicle 6 crosses the first optical fiber cable 5a and the second optical fiber cable 5b, based on the first detection position and its detection time, and the second detection position and its detection time. With the above configuration, the crossing speed v can be estimated by a simple calculation.

[0051] Furthermore, the monitoring device 4 includes a movement estimation unit 15 (movement estimation means). Based on the estimation results from the crossing angle estimation unit 13 and the crossing speed estimation unit 14, the movement estimation unit 15 estimates the movement of the vehicle 6 after it has crossed the first optical fiber cable 5a and the second optical fiber cable 5b. With this configuration, it is possible to effectively track the vehicle 6 as it crosses the optical fiber sensor 3.

[0052] Furthermore, the movement estimation unit 15's estimation of the vehicle 6's movement includes estimating at least one of the following: the azimuth angle of the vehicle 6's movement, the vehicle 6's origin, the vehicle 6's destination, and the time of arrival of the vehicle 6 at its destination. This configuration contributes to the effective tracking of the vehicle 6 as it crosses the optical fiber sensor 3.

[0053] Furthermore, the monitoring device 4 includes an output unit 16 (output means) that superimposes the estimation results from the movement estimation unit 15 onto the map m and outputs them. With the above configuration, proactive responses to vehicles 6 that cross the optical fiber sensor 3 become easier.

[0054] The first embodiment described above can be modified, for example, as follows.

[0055] Specifically, as shown in Figure 7, the output unit 16 generates a superimposed image M by superimposing the estimation result from the movement estimation unit 15 onto the map m. Here, the estimation result from the movement estimation unit 15 is the linear movement trajectory s of the vehicle 6, with the crossing point 7a as a passing point. In other words, the output unit 16 generates a superimposed image M by superimposing the movement trajectory s onto the map m.

[0056] Furthermore, the scope of application of surveillance system 1 is not limited to border 2; it can also be applied to, for example, the boundaries of power plants, airports, military / secret facilities, plants, and farm sites.

[0057] Furthermore, the crossing speed estimation unit 14 may determine that there is no vehicle 6 that crossed the first optical fiber cable 5a and the second optical fiber cable 5b if the difference between the detection time of the first detection position and the detection time of the second detection position is greater than or equal to a predetermined value. That is, it is assumed that a vehicle 6 crossing a border 2 without barriers will not stay near the border 2 for a long time and will leave the border 2 quickly after crossing. By utilizing this characteristic, if the crossing of the vehicle 6 does not occur quickly, it may be determined that there is no vehicle 6 that crossed the border 2 in the first place.

[0058] Furthermore, the crossing speed estimation unit 14 may estimate the type of moving object based on the estimated crossing speed. That is, since moving objects move at a speed corresponding to their type, it is considered that the type of moving object can be estimated from the crossing speed. For example, if the crossing speed of a moving object is 1 to 2 meters per second, it is considered that the moving object is a person traveling on foot. Also, if the crossing speed of a moving object is 10 to 30 kilometers per hour, it is considered that the moving object is a horse. Also, if the crossing speed of a moving object is 30 kilometers per hour or more, it is considered that the moving object is an automobile.

[0059] (Second Embodiment) Next, a second embodiment of the present disclosure will be described. The following description will focus on the differences between this embodiment and the first embodiment, and redundant explanations will be omitted. Figure 8 is a schematic diagram of the monitoring system 1.

[0060] In this embodiment, the optical fiber sensor 3 comprises a third optical fiber cable 5c in addition to the first optical fiber cable 5a and the second optical fiber cable 5b. Figure 7 shows the crossing point 7a where the vehicle 6 crosses the first optical fiber cable 5a, the crossing point 7b where the vehicle 6 crosses the second optical fiber cable 5b, and the crossing point 7c where the vehicle 6 crosses the third optical fiber cable 5c. By increasing the number of optical fiber cables 5 that constitute the optical fiber sensor 3 in this way, the number of times the vehicle 6 crosses the optical fiber cables 5 increases, thereby suppressing false detections and over-detections regarding the vehicle 6 crossing the optical fiber sensor 3. Therefore, the number of optical fiber cables 5 that constitute the optical fiber sensor 3 may be, for example, four or more.

[0061] (Third Embodiment) Next, a third embodiment of the present disclosure will be described. The following description will focus on the differences between this embodiment and the second embodiment described above, and redundant explanations will be omitted. Figure 9 is a schematic diagram of the monitoring system 1.

[0062] In the second embodiment described above, as shown in Figure 8, the monitoring system 1 includes one optical fiber sensor 3. In contrast, in this embodiment, as shown in Figure 9, the monitoring system 1 includes two optical fiber sensors 3 spaced apart. The two optical fiber sensors 3 include a first optical fiber sensor 3a and a second optical fiber sensor 3b. The first optical fiber sensor 3a and the second optical fiber sensor 3b extend parallel to each other.

[0063] Each optical fiber sensor 3 includes, for example, three optical fiber cables 5. In each optical fiber sensor 3, the three optical fiber cables 5 extend parallel to each other. In each optical fiber sensor 3, the three optical fiber cables 5 are arranged at equal intervals. In each optical fiber sensor 3, the three optical fiber cables 5 do not necessarily have to be arranged at equal intervals. In each optical fiber sensor 3, the distance J between two adjacent optical fiber cables 5 is smaller than the distance K between two optical fiber sensors 3. The distance K between two optical fiber sensors 3 is the distance between the optical fiber cable 5 closest to the second optical fiber sensor 3b among the three optical fiber cables 5 constituting the first optical fiber sensor 3a, and the optical fiber cable 5 closest to the first optical fiber sensor 3a among the three optical fiber cables 5 constituting the second optical fiber sensor 3b. The transverse angle estimation unit 13 then estimates the transverse angle θ for each optical fiber sensor 3 and averages the estimated transverse angles θ. Similarly, the transverse velocity estimation unit 14 estimates the transverse velocity v for each optical fiber sensor 3 and averages the estimated transverse velocities v. This allows for the estimation of the transverse angle θ and transverse velocity v with high accuracy.

[0064] <Example of Hardware Configuration> The following describes how each functional configuration of the monitoring device 4 is realized through a combination of hardware and software.

[0065] Figure 10 is a block diagram illustrating the hardware configuration of a computer. The device in this disclosure can realize the above-described functions using a computer 500 including the hardware configuration shown in Figure 10. The computer 500 may be a portable computer such as a smartphone or tablet terminal, or a stationary computer such as a PC. The computer 500 may be a dedicated computer designed to realize each device, or it may be a general-purpose computer. The computer 500 can realize the corresponding functions by installing a predetermined program.

[0066] The computer 500 includes a bus 502, a processor 504, memory 506, a storage device 508, an input / output interface 510 (an interface is also called an I / F (Interface)), and a network interface 512. The bus 502 is a data transmission path for the processor 504, memory 506, storage device 508, input / output interface 510, and network interface 512 to send and receive data to and from each other. However, the method of connecting the processor 504 and the other components to each other is not limited to a bus connection.

[0067] The processor 504 is a variety of processor such as a CPU, GPU, or FPGA. The memory 506 is a main memory implemented using RAM (Random Access Memory) or the like.

[0068] The storage device 508 is an auxiliary storage device implemented using a hard disk, SSD, memory card, or ROM (Read Only Memory). The storage device 508 stores a program for implementing a predetermined function. The processor 504 reads this program into the memory 506 and executes it to implement each functional component of each device.

[0069] The input / output interface 510 is an interface for connecting the computer 500 with input / output devices. For example, input devices such as keyboards and output devices such as display devices are connected to the input / output interface 510.

[0070] The network interface 512 is an interface for connecting the computer 500 to a network.

[0071] The above describes examples of hardware configurations in this disclosure, but the embodiments described above are not limited thereto. This disclosure can also be implemented by having a processor execute a computer program to perform any processing.

[0072] In the examples described above, the program includes a set of instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more of the functions described in the embodiments. The program may be stored on a non-temporary computer-readable medium or a physical storage medium. Examples, but not limited to, include random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technologies, CD-ROM, digital versatile disc (DVD), Blu-ray® disc or other optical disc storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices. The program may be transmitted over a temporary computer-readable medium or a communication medium. Examples, but not limited to, include temporary computer-readable medium or a communication medium that includes electrical, optical, acoustic or other forms of propagating signals.

[0073] Although the present disclosure has been described above with reference to embodiments, the present disclosure is not limited to the embodiments described above. Various modifications to the structure and details of the present disclosure can be made that will be understood by those skilled in the art within the scope of the present disclosure. The first to third embodiments can be implemented in any combination.

[0074] Each drawing is merely illustrative to illustrate one or more embodiments. Each drawing may be associated with one or more other embodiments, rather than being associated with only one specific embodiment. As those skilled in the art will understand, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings, for example, to create embodiments not explicitly shown or described. Not all features or steps shown in any one drawing to illustrate an exemplary embodiment are necessarily required, and some features or steps may be omitted. The order of steps described in any of the drawings may be changed as appropriate.

[0075] Some or all of the above embodiments may also be described as follows, but are not limited to the following: (Note 1) A monitoring system comprising: a detection position acquisition means for acquiring a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable; and a cross-sectional angle estimation means for estimating the cross-sectional angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position. (Note 2) A monitoring system according to Note 1, wherein the first optical fiber cable and the second optical fiber cable are provided parallel to each other, and the cross-sectional angle estimation means estimates the cross-sectional angle based on the difference between the first detection position and the second detection position in the longitudinal direction of the first optical fiber cable and the distance between the first optical fiber cable and the second optical fiber cable. (Note 3) A monitoring system according to Note 1, further comprising a crossing velocity estimation means for estimating the crossing velocity when the moving body crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the detection time, and the second detection position and the detection time. (Note 4) A monitoring system according to Note 3, further comprising a movement estimation means for estimating the movement of the moving body after it has crossed the first optical fiber cable and the second optical fiber cable based on the estimation result by the crossing angle estimation means and the estimation result by the crossing velocity estimation means. (Note 5) A monitoring system according to Note 4, wherein the movement estimation means estimating the movement of the moving body includes estimating at least one of the azimuth angle of the movement of the moving body, the starting point of the moving body, the destination of the moving body, and the time of arrival of the moving body at the destination.(Note 6) A monitoring system as described in Note 3, wherein the crossing velocity estimation means determines that there is no moving object that has crossed the first optical fiber cable and the second optical fiber cable if the difference between the detection time of the first detection position and the detection time of the second detection position is greater than or equal to a predetermined value. (Note 7) A monitoring system as described in Note 3, wherein the crossing velocity estimation means estimates the type of moving object based on the estimated crossing velocity. (Note 8) A monitoring device comprising: detection position acquisition means for acquiring a first detection position where vibration is detected in the first optical fiber cable and a second detection position where vibration is detected in the second optical fiber cable located at a distance from the first optical fiber cable; and crossing angle estimation means for estimating the crossing angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position. (Note 9) A monitoring method comprising: a computer acquiring a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable; and estimating the crossing angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position. (Note 10) A program that causes a computer to function as: a detection position acquisition means for acquiring a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable; and a crossing angle estimation means for estimating the crossing angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position.

[0076] Some or all of the elements (e.g., configuration and function) described in Appendices 2 to 7 that are subordinate to Appendice 1 may also be subordinate to Appendices 8 to 10 in the same manner as those described in Appendices 2 to 7. Some or all of the elements described in any appendice may be applied to various hardware, software, recording means, systems, and methods for recording software.

[0077] This application claims priority based on Japanese Patent Application No. 2024-189608, filed on 29 October 2024, and incorporates all of its disclosures herein.

[0078] 1. Monitoring system 2. Border 3. Optical fiber sensor 3a. First optical fiber sensor 3b. Second optical fiber sensor 4. Monitoring device 5. Optical fiber cable 5a. First optical fiber cable 5b. Second optical fiber cable 5c. Third optical fiber cable 6. Vehicle 7a. Crossing point 7b. Crossing point 7c. Crossing point 10. Detection data storage unit 11. Map data storage unit 12. Detection position acquisition unit 13. Crossing angle estimation unit 14. Crossing speed estimation unit 15. Movement estimation unit 16. Output unit

Claims

1. A monitoring system comprising: a detection position acquisition means for acquiring a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable; and a crossing angle estimation means for estimating the crossing angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position.

2. A monitoring system according to claim 1, wherein the first optical fiber cable and the second optical fiber cable are provided parallel to each other, and the cross-sectional angle estimation means estimates the cross-sectional angle based on the difference between the first detection position and the second detection position in the longitudinal direction of the first optical fiber cable, and the distance between the first optical fiber cable and the second optical fiber cable.

3. A monitoring system according to claim 1, further comprising a crossing velocity estimation means for estimating the crossing velocity when a moving object crosses the first optical fiber cable and the second optical fiber cable, based on the first detection position and the detection time, and the second detection position and the detection time.

4. A monitoring system according to claim 3, further comprising a movement estimation means for estimating the movement of the moving body after it has crossed the first optical fiber cable and the second optical fiber cable, based on the estimation result by the crossing angle estimation means and the estimation result by the crossing velocity estimation means.

5. The monitoring system according to claim 4, wherein the movement estimation means estimates the movement of the moving body by estimating at least one of the azimuth angle of the movement of the moving body, the origin of the moving body, the destination of the moving body, and the time of arrival of the moving body at the destination.

6. A monitoring system according to claim 3, wherein the crossing speed estimation means determines that there is no moving object that has crossed the first optical fiber cable and the second optical fiber cable if the difference between the detection time of the first detection position and the detection time of the second detection position is greater than or equal to a predetermined value.

7. A monitoring system according to claim 3, wherein the crossing speed estimation means estimates the type of moving object based on the estimated crossing speed.

8. A monitoring device comprising: a detection position acquisition means for acquiring a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable; and a cross-sectional angle estimation means for estimating the cross-sectional angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position.

9. A monitoring method comprising: a computer acquiring a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable; and estimating the crossing angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first and second detection positions.

10. A program that causes a computer to function as: a detection position acquisition means for acquiring a first detection position where vibration is detected in a first optical fiber cable and a second detection position where vibration is detected in a second optical fiber cable located at a distance from the first optical fiber cable; and a cross-sectional angle estimation means for estimating the cross-sectional angle when a moving object crosses the first optical fiber cable and the second optical fiber cable based on the first detection position and the second detection position.

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