Vehicle type discrimination system, NP reading device, vehicle type discrimination method, and vehicle type discrimination program

Abstract

To realize a vehicle type discrimination system at low cost.SOLUTION: A vehicle detector 100 transmits a vehicle detection signal 21. An NP reading device 200 is installed in a front position in a direction of travel, and upon receiving the vehicle detection signal 21, images the front of a vehicle 10 and reads NP information 31 from a front vehicle image. The NP reading device 200 calculates a speed of the vehicle 10 as a detection vehicle speed 32 by means of moving body detection. The NP reading device 200 transmits the NP information 31 and the detection vehicle speed 32. An axle number sensor 300 acquires and transmits an axle number 34 of the vehicle. A data processing device 400 uses the vehicle detection signal 21 and the detection vehicle speed 32 to calculate a vehicle length and uses the NP information 31 and information including the axle number 34 and the vehicle length 41 to discriminate a vehicle type 50 of the vehicle.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle type discrimination system, a NP reading device, a vehicle type discrimination method, and a vehicle type discrimination program. In particular, the present disclosure relates to a vehicle type discrimination system, a NP reading device, a vehicle type discrimination method, and a vehicle type discrimination program that discriminate between five vehicle types used to determine the toll classification for vehicles passing through toll gates. NP is an abbreviation for Number Plate. [Background technology]

[0002] ETC (registered trademark) tolls are generally divided into five vehicle type categories: light / two-wheeled vehicles, standard vehicles, medium-sized vehicles, large vehicles, and extra-large vehicles. ETC (registered trademark) is an abbreviation for Electronic Toll Collection System. These toll categories are registered information stored in the ETC (registered trademark) on-board unit installed in the vehicle. However, if only the registration information of the ETC (registered trademark) on-board unit is available, there is a possibility that the vehicle type may be falsified due to the replacement of the on-board unit, etc. Therefore, the vehicle type determination device determines the vehicle type from information such as the vehicle dimensions and number of axles.

[0003] Patent Document 1 discloses a technology that refers to the reflection data used for vehicle detection, calculates the vehicle height, width, and length by observing the cross section of the vehicle body shape, and identifies the towing condition and number of axles to determine the vehicle type. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-204174 Summary of the Invention [Problem to be solved by the invention]

[0005] A typical vehicle type identification device requires many sensors, such as sensors for vehicle length and width. To detect vehicle length, two pairs of vehicle detectors are arranged, and the vehicle's passing time and speed are calculated to calculate the vehicle length. This method has high accuracy in calculating vehicle length for vehicles traveling at a constant speed between the vehicle detectors. However, there is an issue in that the vehicle length cannot be correctly identified for vehicles that stop temporarily.

[0006] The present disclosure aims to realize a vehicle type discrimination system at low cost by discriminating vehicle types using a small number of sensors. [Means for solving the problem]

[0007] The vehicle type discrimination system according to the present disclosure is a vehicle type discrimination system that discriminates the vehicle type of a vehicle entering a toll gate, a vehicle detector that, upon detecting the vehicle, transmits a vehicle detection signal indicating that the vehicle has been detected; an NP reading device that is installed in a position ahead of the vehicle detector in the traveling direction, and that, upon receiving the vehicle detection signal, takes an image of the area ahead of the vehicle as a forward vehicle image, reads the NP (Number Plate) of the vehicle from the forward vehicle image as NP information, and calculates the speed of the vehicle as a detected vehicle speed by detecting a moving object, and transmits the NP information and the detected vehicle speed; an axle number sensor that is installed at a location where the vehicle detector is installed, and that acquires the number of axles of the vehicle when the vehicle runs over it, and transmits the number of axles; The vehicle detection system is equipped with a data processing device that calculates the vehicle length, which is the length of the vehicle, using the vehicle detection signal and the detected vehicle speed, and determines the vehicle type using information including the NP information, the number of axles, and the vehicle length. [Effects of the Invention]

[0008] In the vehicle type discrimination system according to the present disclosure, the NP reader calculates the vehicle speed as the detected vehicle speed by detecting a moving object and transmits the NP information and the detected vehicle speed. The data processing device then calculates the vehicle length using the vehicle detection signal and the detected vehicle speed, and discriminates the vehicle type using the NP information, the number of axles, and the vehicle length. Therefore, the vehicle type discrimination system according to the present disclosure can discriminate the vehicle type with a small number of sensors, thereby achieving the effect of realizing a vehicle type discrimination system at low cost. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing an example of the configuration of a vehicle type discrimination system according to a first embodiment. [Figure 2] 1 is a schematic diagram showing the overall configuration of a vehicle type discrimination system according to a first embodiment. [Figure 3] FIG. 2 is a diagram showing an example of the functional configuration of the NP reading device according to the first embodiment. [Figure 4] 1 is a schematic diagram showing the overall configuration of an ETC (registered trademark) system as a comparative example for comparison with the vehicle type discrimination system according to the first embodiment; [Figure 5] 3 is a flowchart showing an example of the operation of the vehicle type discrimination system according to the first embodiment. [Figure 6] FIG. 10 is a diagram showing a first example of a hardware configuration of each device in the vehicle type discrimination system according to a modified example of the first embodiment. [Figure 7] FIG. 10 is a diagram showing a second example of the hardware configuration of each device in the vehicle type discrimination system according to a modified example of the first embodiment. [Figure 8] FIG. 10 is a flowchart showing an example of the operation of the vehicle type discrimination system according to the second embodiment. [Figure 9] FIG. 10 is a diagram showing an example of the configuration of a vehicle type discrimination system according to a third embodiment. [Figure 10] FIG. 11 is a schematic diagram showing the overall configuration of a vehicle type discrimination system according to a third embodiment. [Figure 11] FIG. 11 is a flowchart showing an example of the operation of the vehicle type discrimination system 500 according to the third embodiment. [Figure 12] FIG. 10 is a diagram showing a vehicle width detection method according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present embodiment will be described below with reference to the drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals. In the description of the embodiment, the description of identical or corresponding parts will be omitted or simplified as appropriate. Arrows in the drawings mainly indicate the flow of data or the flow of processing. Furthermore, the sized relationships between components in the following drawings may differ from the actual relationships. Furthermore, in the description of the embodiment, directions or positions such as up, down, left, right, front, rear, front and back may be indicated. These notations are used for convenience of explanation and do not limit the placement, direction or orientation of devices, instruments, parts, etc.

[0011] Embodiment 1 ***Configuration Description*** FIG. 1 is a diagram showing an example of the configuration of a vehicle type discrimination system 500 according to this embodiment. FIG. 2 is a schematic diagram showing the overall configuration of a vehicle type discrimination system 500 according to this embodiment. The vehicle type determination system 500 according to this embodiment is a system that determines the vehicle type of a vehicle 10 that passes through a toll gate. The vehicle type determination system 500 is used, for example, to determine the vehicle type for toll classification in an ETC (registered trademark) system.

[0012] The vehicle type discrimination system 500 includes a vehicle detector 100, an NP reader 200, an axle number sensor 300, and a data processor 400. NP is an abbreviation for Number Plate. The data processing device 400 communicates with each of the vehicle detector 100, the NP reader 200, and the axle number sensor 300 wirelessly or via wires.

[0013] The vehicle detector 100 detects the vehicle 10. When the vehicle detector 100 detects that the vehicle 10 has entered, it transmits a vehicle detection signal 21 indicating that the vehicle 10 has been detected. In this embodiment, only one vehicle detector 100 is required.

[0014] The NP reader 200 is installed at a position ahead of the vehicle detector 100 in the traveling direction. When the NP reader 200 receives the vehicle detection signal 21, it captures an image of the area ahead of the vehicle 10 as a forward vehicle image. The NP reader 200 reads the NP of the vehicle 10 from the forward vehicle image as NP information 31. The NP reader 200 also has a moving object detection function. The NP reader 200 calculates the speed of the vehicle 10 as a detected vehicle speed 32 by detecting a moving object. The NP reader 200 also measures the vehicle width 33 of the vehicle 10 by processing the image of the vehicle ahead. The NP reader 200 transmits the NP information 31, the detected vehicle speed 32, and the vehicle width 33 to the data processor 400.

[0015] FIG. 3 is a diagram showing an example of the functional configuration of the NP reader 200 according to this embodiment. The NP reader 200 includes a camera 22 , an NP acquisition unit 210 , a speed calculation unit 220 , and a vehicle width measurement unit 230 . When the camera 22 receives the vehicle detection signal 21, it takes an image of the vehicle 10. The NP acquisition unit 210 reads the NP of the vehicle 10 as NP information 31 by performing image processing on the image of the vehicle ahead captured by the camera 22 . The speed calculation unit 220 calculates the detected vehicle speed 32 by detecting a moving object based on the image of the vehicle 10 captured by the camera 22 . The vehicle width measurement unit 230 measures the vehicle width 33 of the vehicle 10 by processing the image of the vehicle ahead. The NP reader 200 also includes a communication device that transmits the NP information 31, the detected vehicle speed 32, and the vehicle width 33 to the data processor 400.

[0016] The axle number sensor 300 is installed at the same location as the vehicle detector 100. The axle number sensor 300 acquires the number of axles 33 of the vehicle 10 when it is run over by the vehicle 10. The axle number sensor 300 transmits the number of axles 33 to the data processing device 400. The axle number sensor 300 is also called an axle number counter. The axle number sensor 300 is structured so that it electrically shorts out when it is run over by the tire of the vehicle 10. A signal indicating that the vehicle 10 has run over the axle number sensor 300 is transmitted to the data processing device 400 as a contact pulse signal.

[0017] The data processing device 400 calculates the vehicle length 41, which is the length of the vehicle, using the vehicle detection signal 21 and the detected vehicle speed 32. The data processing device 400 also determines the vehicle model 50 of the vehicle 10 using information including the NP information 31, the number of axles 34, and the vehicle length 41. More specifically, the data processing device 400 determines the vehicle model 50 of the vehicle 10 using the NP information 31, the number of axles 34, the vehicle length 41, and the vehicle width 33. The data processing device 400 is a computer that determines the toll category for each vehicle type of vehicle 10 passing through the toll gate and determines the toll. The data processing device 400 may be installed anywhere as long as it can communicate with the roadside devices 960, such as the axle number sensor 300, the NP reader 200, and the vehicle detector 100 in the vehicle type determination system 500. The vehicle 10 is also equipped with an on-board unit for ETC (registered trademark) charging. The on-board unit stores registration information. The registration information stores a vehicle-specific fee classification, which is a fee classification for each vehicle type of the vehicle 10. For example, one of five vehicle-specific fee classifications, light / two-wheel, standard-sized vehicle, medium-sized vehicle, large vehicle, and extra-large vehicle, is registered as the vehicle-specific fee classification. The data processing device 400 transmits the determined vehicle model 50 of the vehicle 10 to the vehicle-mounted device of the vehicle 10 .

[0018] FIG. 4 is a schematic diagram showing the overall configuration of an ETC (registered trademark) system as a comparative example for comparison with the vehicle type discrimination system 500 according to this embodiment. The vehicle type discrimination system in the ETC (registered trademark) system of the comparative example includes an NP reader, vehicle detector 1, vehicle detector 2, a vehicle width sensor, an axle number sensor, and a data processing device. The data processing device uses the NP reader, vehicle detector 1, vehicle detector 2, vehicle width sensor, and axle number sensor to obtain NP information, vehicle length, vehicle width, and number of axles. The data processing device then discriminates the vehicle type based on the NP information, vehicle length, vehicle width, and number of axles. In the vehicle type discrimination system of the comparative example, the installation distance between vehicle detector 1 and vehicle detector 2 is known in advance, so the vehicle speed is calculated using the following formula. Vehicle speed [m / s] = distance between vehicle detector 1 and vehicle detector 2 [m] / (time when vehicle detector 2 is on [s] - time when vehicle detector 1 is on [s]) Vehicle length [m] = time it takes for vehicle detector 1 to pass [s] × vehicle speed [m / s] However, the above calculation in the vehicle type identification system of the comparative example is accurate for vehicles traveling at a constant speed, but has the problem that it is not accurate for vehicles that stop temporarily or are in a traffic jam. Also, compared to the vehicle type identification system 500 of this embodiment, two vehicle detectors and a vehicle width sensor are required.

[0019] ***Explanation of Operation*** FIG. 5 is a flow diagram showing an example of the operation of the vehicle type discrimination system 500 according to this embodiment. The operation of the vehicle type discrimination system 500 according to this embodiment will be described. The operating procedure of the vehicle type discrimination system 500 corresponds to a vehicle type discrimination method. Furthermore, the program that realizes the operation of the vehicle type discrimination system 500 corresponds to a vehicle type discrimination program.

[0020] In step S101, the vehicle detector 100 detects the entry of the vehicle 10. When the vehicle detector 100 detects the entry of the vehicle 10, it transmits a vehicle detection signal 21 to the NP reader 200 and the data processing device 400. Note that the vehicle detector 100 may transmit the vehicle detection signal 21 to the NP reader 200 via the data processing device 400.

[0021] In step S102, upon receiving the vehicle detection signal 21, the NP reading device 200 photographs the vehicle 10 from the front and obtains a front vehicle image of the vehicle 10 photographed from the front. The NP reading device 200 performs image processing on the front vehicle image to read the NP of the vehicle 10 as NP information 31. The NP reading device 200 transmits the NP information 31 to the data processing device 400.

[0022] In step S103, upon receiving the vehicle detection signal 21, the NP reader 200 calculates the speed of the vehicle 10 as the detected vehicle speed 32 by detecting a moving object. Specifically, upon receiving the vehicle detection signal 21, the NP reader 200 calculates the detected vehicle speed 32 by detecting a moving object based on the image of the vehicle 10 captured by the camera 22. The NP reader 200 transmits the detected vehicle speed 32 to the data processing device 400.

[0023] In step S104, the NP reader 200 measures the vehicle width 33 of the vehicle 10 by image processing the image of the vehicle ahead. The NP reader 200 calculates position information of the left and right edges of the vehicle 10 by image processing the image of the vehicle ahead. The NP reader 200 transmits the position information of the left and right edges of the vehicle 10 to the data processing device 400. Then, the data processing device 400 measures the vehicle width 33 of the vehicle 10 using the position information of the left and right edges of the vehicle 10.

[0024] In step S105, the axle number sensor 300 is stepped on by the vehicle 10 to obtain the number of axles 33 of the vehicle 10. For example, the axle number sensor 300 is a step-type axle number sensor. The axle number sensor 300 transmits the number of axles 33 to the data processing device 400. The axle number sensor 300 may transmit the number of axles 33 to the data processing device 400 via the vehicle detector 100.

[0025] In step S106, the data processing device 400 calculates the vehicle length 41 from the vehicle detection signal 21 and the detected vehicle speed 32.

[0026] In step S107, the data processing device 400 determines the vehicle model 50 of the vehicle 10 using information including the NP information 31, the number of axles 34, and the vehicle length 41. More specifically, the data processing device 400 determines the vehicle model 50 of the vehicle 10 using the NP information 31, the number of axles 34, the vehicle length 41, and the vehicle width 33. For example, the data processing device 400 determines the vehicle model 50 of the vehicle 10 using a table of information such as the classification number of the NP information, the license plate size, the vehicle length, and the vehicle width.

[0027] The data processing device 400 transmits the determined vehicle model 50 of the vehicle 10 to the ETC (registered trademark) in-vehicle unit of the vehicle 10.

[0028] ***Explanation of hardware configuration example*** The vehicle detector 100, NP reader 200, axle number sensor 300, and data processor 400 provided in the vehicle type discrimination system 500 are each equipped with a computer. The vehicle detector 100, the NP reader 200, the axle number sensor 300, and the data processing device 400 provided in the vehicle type discrimination system 500 may be referred to as each device of the vehicle type discrimination system 500.

[0029] <Hardware configuration example 1> FIG. 6 is a diagram showing a first example of a hardware configuration of each device of a vehicle type discrimination system 500 according to this embodiment.

[0030] Each device in the vehicle type discrimination system 500 is a computer. Each device in the vehicle type discrimination system 500 includes a processor 910, as well as other hardware such as a memory 921, an auxiliary storage device 922, an input / output interface 930, and a communication interface 950. The processor 910 is connected to the other hardware via a signal line 80 and controls the other hardware. The functions of each device in the vehicle type discrimination system 500 are realized by software.

[0031] For example, the functional elements of the NP reader 200 are an NP acquisition unit 210, a speed calculation unit 220, and a vehicle width measurement unit 230. The functions of the NP acquisition unit 210, the speed calculation unit 220, and the vehicle width measurement unit 230 are realized by software.

[0032] The processor 910 is a device that executes a vehicle type discrimination program. The vehicle type discrimination program is a program that realizes the functions of each device in the vehicle type discrimination system 500. The processor 910 is an IC that performs arithmetic processing. Specific examples of the processor 910 are a CPU, a DSP, and a GPU. IC is an abbreviation for Integrated Circuit. CPU is an abbreviation for Central Processing Unit. DSP is an abbreviation for Digital Signal Processor. GPU is an abbreviation for Graphics Processing Unit.

[0033] The memory 921 is a storage device that temporarily stores data. Specific examples of the memory 921 are SRAM and DRAM. SRAM is an abbreviation for Static Random Access Memory. DRAM is an abbreviation for Dynamic Random Access Memory. The auxiliary storage device 922 is a storage device that stores data. A specific example of the auxiliary storage device 922 is a HDD. The auxiliary storage device 922 may also be a portable storage medium such as an SD (registered trademark) memory card, CF, NAND flash, a flexible disk, an optical disk, a compact disk, a Blu-ray (registered trademark) disk, or a DVD. Note that HDD is an abbreviation for Hard Disk Drive. SD (registered trademark) is an abbreviation for Secure Digital. CF is an abbreviation for CompactFlash (registered trademark). DVD is an abbreviation for Digital Versatile Disk.

[0034] The input / output interface 930 is an interface for connecting an input / output device. Specific examples of the input / output interface 930 include a USB or HDMI (registered trademark) port. USB is an abbreviation for Universal Serial Bus. HDMI (registered trademark) is an abbreviation for High-Definition Multimedia Interface.

[0035] The communication interface 950 is an interface for communicating with an external device, and is specifically an Ethernet (registered trademark) port or a device for wireless communication.

[0036] The vehicle type discrimination program is executed in each device of the vehicle type discrimination system 500. The vehicle type discrimination program is read into the processor 910 and executed by the processor 910. The memory 921 stores not only the vehicle type discrimination program but also an OS. OS is an abbreviation for Operating System. The processor 910 executes the vehicle type discrimination program while running the OS. The vehicle type discrimination program and the OS may be stored in an auxiliary storage device 922. The vehicle type discrimination program and the OS stored in the auxiliary storage device 922 are loaded into the memory 921 and executed by the processor 910. Note that part or all of the vehicle type discrimination program may be incorporated into the OS.

[0037] Each device of the vehicle type discrimination system 500 may include multiple processors that replace the processor 910. These multiple processors share the task of executing the vehicle type discrimination program. Each processor is a device that executes the vehicle type discrimination program in the same way as the processor 910.

[0038] The data, information, signal values ​​and variable values ​​used, processed or output by the vehicle type discrimination program are stored in the memory 921, the auxiliary storage device 922, or a register or cache memory within the processor 910.

[0039] The functions of each device in the vehicle type discrimination system 500 may be interpreted as "units," "circuits," "steps," "procedures," "processing," or "circuitry." The vehicle type discrimination program causes a computer to execute each process in which the functions of each device in the vehicle type discrimination system 500 are interpreted as "processing." The "processing" in each process in which the functions of each device in the vehicle type discrimination system 500 are interpreted as "processing" may be interpreted as a "program," "program product," "computer-readable storage medium storing a program," or "computer-readable storage medium recording a program." Furthermore, the vehicle type discrimination method is a method performed by each device in the vehicle type discrimination system 500 executing the vehicle type discrimination program. The vehicle type discrimination program may be provided by being stored in a computer-readable recording medium, or may be provided as a program product.

[0040] <Hardware configuration example 2> In the above hardware configuration example 1, the functions of each device in the vehicle type discrimination system 500 are realized by software. In hardware configuration example 2, the functions of each device in the vehicle type discrimination system 500 may be realized by hardware. Specifically, each device of the vehicle type discrimination system 500 includes an electronic circuit 909 instead of a processor 910 .

[0041] FIG. 7 is a diagram showing a second example of the hardware configuration of each device of a vehicle type discrimination system 500 according to a modified example of this embodiment. The electronic circuit 909 is a dedicated electronic circuit that realizes the functions of each device in the vehicle type identification system 500. Specifically, the electronic circuit 909 is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA, an ASIC, or an FPGA. GA is an abbreviation for Gate Array. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field-Programmable Gate Array.

[0042] The functions of each device of the vehicle type discrimination system 500 may be realized by one electronic circuit, or may be distributed and realized by multiple electronic circuits.

[0043] As another modification, some of the functions of each device in the vehicle type identification system 500 may be implemented by electronic circuits, and the remaining functions may be implemented by software. Also, some or all of the functions of each device in the vehicle type identification system 500 may be implemented by firmware.

[0044] Each of the processor and electronic circuits is also called a processing circuitry. In other words, the functions of each device in the vehicle type identification system 500 are realized by the processing circuitry.

[0045] ***Explanation of the effect of this embodiment*** As described above, in the vehicle type discrimination system according to this embodiment, the NP reader calculates the vehicle speed as the detected vehicle speed by detecting a moving object and transmits the NP information and the detected vehicle speed. The data processor then calculates the vehicle length using the vehicle detection signal and the detected vehicle speed, and discriminates the vehicle type using the NP information, the number of axles, and the vehicle length. Therefore, the vehicle type discrimination system according to this embodiment can discriminate the vehicle type with high accuracy using a small number of sensors, thereby realizing a low-cost, high-accuracy vehicle type discrimination system.

[0046] For example, one method for detecting vehicle width is to use two distance sensors to measure the distance to the side of the vehicle, but this method requires two distance sensors, which is costly. In the vehicle type discrimination system according to this embodiment, a function for measuring vehicle speed is added to the NP reader, which is one of the components of the vehicle type discrimination system. The NP reader also has a function for measuring vehicle width. This eliminates the need for sensors such as a vehicle length sensor and a vehicle width sensor, making it possible to build a low-cost system.

[0047] Embodiment 2 In this embodiment, differences from and additions to the first embodiment will be mainly described. In this embodiment, components having the same functions as those in the first embodiment are given the same reference numerals, and the description thereof will be omitted.

[0048] The configuration of the vehicle type discrimination system 500 according to this embodiment is the same as that of the first embodiment.

[0049] ***Explanation of Operation*** FIG. 8 is a flow diagram showing an example of the operation of the vehicle type discrimination system 500 according to this embodiment. The processes from step S101 to step S102 and step S104 to step S107 are the same as those in the first embodiment. In step S103a, the NP reader 200 calculates the detected vehicle speed 32 based on the sum of a plurality of vehicle speeds acquired by moving object detection until the vehicle 10 passes the vehicle detector 100. Specifically, it is as follows:

[0050] The NP reader 200 calculates the vehicle speed using the following formula. Vehicle length [m] = vehicle speed calculation interval [s] × (vehicle speed (1) [m / s] + vehicle speed (2) [m / s] + + vehicle speed (n) [m / s])

[0051] As described above, the NP reader 200 calculates the speed while passing the vehicle detector 100 by integrating it. This makes it possible to calculate the length of vehicles that have stopped temporarily, improving the accuracy of vehicle type identification. In addition, the axle detection signal from the axle number sensor can be used to improve the accuracy of the axle distance based on the timing at which the axle (tire) is pressed down, thereby improving the accuracy of vehicle type identification.

[0052] ***Explanation of the effect of this embodiment*** As described above, the vehicle type discrimination system according to this embodiment has the following advantages. In the above embodiment, an object detection method (for example, HOG, R-CNN, YOLO, SSD, DCN, background subtraction, etc.) is used to detect the speed. In this way, by detecting the speed of an object and performing a convolution calculation with the speed at the time of passing through the vehicle detector 1, it is possible to calculate an accurate vehicle length, and it is possible to reduce the number of vehicle detectors.

[0053] In the comparative example of embodiment 1, calculations were performed using the speed (one type of speed) at the timing when the vehicle passed through vehicle detector 1 and vehicle detector 2. For this reason, accuracy is obtained when the vehicle travels at a constant speed, but accuracy is not obtained when the vehicle decelerates or stops. On the other hand, in this embodiment, vehicle speed is calculated using data for 30 fps (frame rate). This allows for more measurement timing and can also handle vehicle stops. In this way, since the speed can be calculated for each frame, it is possible to calculate the axle-to-axle distance with increased accuracy from the time between the pulse of one axle and the pulse of the next axle, and the speed between them.

[0054] Embodiment 3 In this embodiment, differences from the first and second embodiments and additional features to the first and second embodiments will be mainly described. In this embodiment, components having the same functions as those in the first and second embodiments are given the same reference numerals, and the description thereof will be omitted.

[0055] ***Configuration Description*** FIG. 9 is a diagram showing an example of the configuration of a vehicle type discrimination system 500 according to this embodiment. FIG. 10 is a schematic diagram showing the overall configuration of a vehicle type discrimination system 500 according to this embodiment. In this embodiment, the NP reader 200 includes a front NP reader 201 and a rear NP reader 202.

[0056] The front NP reading device 201 is installed at a position in front of the vehicle detector 100. The front NP reading device 201 is an example of the NP reading device 200 described in the first and second embodiments. The front NP reading device 201 reads the NP of the vehicle 10 as NP information 31 from the front vehicle image.

[0057] The rear NP reader 202 is installed in a rear position in front of the vehicle detector 100. When the rear NP reader 202 receives the vehicle detection signal 21, it captures an image of the area behind the vehicle 10 as a rear vehicle image. The rear NP reader 202 reads the NP of the vehicle 10 from the rear vehicle image as NP information 31. The rear NP reader 202 has the same functions as the NP reader 200 described in the first and second embodiments, except that it photographs the vehicle 10 from behind.

[0058] Moreover, it is preferable that the front NP reader 201 and the rear NP reader 202 are installed at separate positions on the left and right sides of the vehicle detector 100. That is, the front NP reader 201 photographs from the right side and the rear NP reader 202 photographs from the left side of the vehicle 10. Alternatively, the front NP reader 201 photographs from the left side and the rear NP reader 202 photographs from the right side of the vehicle 10. If the front NP reading device 201 and the rear NP reading device 202 are installed at separate left and right positions relative to the vehicle 10, both NP reading devices may be installed at positions that capture images of the front of the vehicle 10. Alternatively, if the front NP reading device 201 and the rear NP reading device 202 are installed at separate left and right positions relative to the vehicle 10, both NP reading devices may be installed at positions that capture images of the rear of the vehicle 10.

[0059] ***Explanation of Operation*** FIG. 11 is a flow chart showing an example of the operation of the vehicle type discrimination system 500 according to this embodiment.

[0060] In step S101b, the vehicle detector 100 detects the entry of the vehicle 10. When the vehicle detector 100 detects the entry of the vehicle 10, it transmits a vehicle detection signal 21 to the front NP reader 201, the rear NP reader 202, and the data processing device 400. Note that the vehicle detector 100 may transmit the vehicle detection signal 21 to the front NP reader 201 and the rear NP reader 202 via the data processing device 400.

[0061] In step S102b, upon receiving the vehicle detection signal 21, the front NP reading device 201 photographs the vehicle 10 from the front and obtains a front vehicle image of the vehicle 10 photographed from the front. The front NP reading device 201 performs image processing on the front vehicle image to read the NP of the vehicle 10 as NP information 31. Similarly, the rear NP reading device 202 performs image processing on the rear vehicle image to read the NP of the vehicle 10 as NP information 31. Each of the front NP reader 201 and the rear NP reader 202 transmits the NP information 31 to the data processing device 400 .

[0062] In step S103b, upon receiving the vehicle detection signal 21, each of the front NP reader 201 and the rear NP reader 202 calculates the speed of the vehicle 10 as the detected vehicle speed 32 by detecting a moving object when the vehicle passes the vehicle detector 100. Each of the front NP reader 201 and the rear NP reader 202 transmits the detected vehicle speed 32 to the data processing device 400.

[0063] In step S104b, the front NP reading device 201 performs image processing on the front vehicle image to calculate position information of the opposite edge of the front vehicle image of the vehicle 10. The rear NP reading device 202 performs image processing on the rear vehicle image to calculate position information of the opposite edge of the rear vehicle image of the vehicle 10. Then, the data processing device 400 calculates the vehicle width 33 using the position information of the left and right edges of the vehicle 100 calculated by the front NP reading device 201 and the rear NP reading device 202, respectively.

[0064] The front NP reader 201 detects edges on the opposite side of the vehicle from the image of the front vehicle, and the rear NP reader 202 detects edges on the opposite side of the vehicle from the image of the rear vehicle. The front NP reader 201 and the rear NP reader 202 are installed separately on the left and right, so that the left and right edges of the vehicle 10 can be detected with high accuracy. The front NP reader 201 and the rear NP reader 202 transmit position information of the left and right edges of the vehicle 10 to the data processing device 400. Using the left and right edges detected with high accuracy, the data processing device 400 calculates the vehicle width 33 of the vehicle 10.

[0065] The processes from step S105 to step S107 are the same as those in the first embodiment.

[0066] FIG. 12 is a diagram showing a vehicle width detection method according to this embodiment. When a single NP reader is used, edge detection using background subtraction or the like makes it easy to detect the edge of the vehicle on the opposite side of the camera. On the other hand, it is difficult to detect the edge of the vehicle on the same side as the camera. Therefore, when a single NP reader is used, the vehicle width measurement accuracy decreases. In this embodiment, two NP readers are installed. In particular, one is installed on each side of the vehicle. The NP reader on the right side of the vehicle detects the edge of the vehicle on the left side of the vehicle. The NP reader on the left side of the vehicle detects the edge of the vehicle on the right side of the vehicle. This allows for highly accurate edge detection, improving the vehicle width measurement accuracy. It also improves the accuracy of vehicle type identification. Both of the two readers may be installed to read from the front. Alternatively, both of the readers may be installed to read from the rear. Alternatively, as shown in FIG. 10, one each for the front and rear may be installed.

[0067] ***Explanation of the effect of this embodiment*** As described above, in the vehicle type identification system according to this embodiment, two cameras, one for the front NP reader and one for the rear NP reader, are installed on the left and right islands. By detecting the rear edge of the vehicle using each NP reader, the accuracy of vehicle width detection can be improved.

[0068] In the above first to third embodiments, the functions of each device in the vehicle type discrimination system have been described as independent functional blocks. However, the configuration of the vehicle type discrimination system does not have to be as in the above-described embodiments. The functional blocks of the vehicle type discrimination system may have any configuration as long as they can realize the functions described in the above-described embodiments. Furthermore, the vehicle type discrimination system may be a single device or a system composed of multiple devices. For example, the NP reader and the data processing device may be integrated. When the NP reader and the data processing device are integrated, the NP acquisition unit, the speed calculation unit, and the vehicle width measurement unit may be included in the data processing device. Furthermore, it is possible to combine two or more parts of the first to third embodiments. Alternatively, it is possible to implement only one part of these embodiments. In addition, it is possible to implement any combination of these embodiments, either as a whole or in part. That is, in the first to third embodiments, the embodiments can be freely combined, or any of the components in each embodiment can be modified, or any of the components in each embodiment can be omitted.

[0069] The above-described embodiments are essentially preferred examples and are not intended to limit the scope of the present disclosure, the scope of application of the present disclosure, or the scope of use of the present disclosure. The above-described embodiments can be modified in various ways as needed. For example, the procedures described using flow charts or sequence diagrams may be modified as appropriate.

[0070] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) In a vehicle type discrimination system that discriminates the type of vehicle entering a toll gate, a vehicle detector that, upon detecting the vehicle, transmits a vehicle detection signal indicating that the vehicle has been detected; an NP reading device that is installed in a position ahead of the vehicle detector in the traveling direction, and that, upon receiving the vehicle detection signal, takes an image of the area ahead of the vehicle as a forward vehicle image, reads the NP (Number Plate) of the vehicle from the forward vehicle image as NP information, and calculates the speed of the vehicle as a detected vehicle speed by detecting a moving object, and transmits the NP information and the detected vehicle speed; an axle number sensor that is installed at a location where the vehicle detector is installed, and that acquires the number of axles of the vehicle when the vehicle runs over it, and transmits the number of axles; a data processing device that calculates a vehicle length, which is a length of the vehicle, using the vehicle detection signal and the detected vehicle speed, and determines a vehicle type of the vehicle using information including the NP information, the number of axles, and the vehicle length; A vehicle type identification system equipped with (Appendix 2) The NP reader is measuring a vehicle width of the vehicle by image processing the image of the vehicle ahead, and transmitting the vehicle width; The data processing device includes: 2. A vehicle type discrimination system according to claim 1, which discriminates the vehicle type using the NP information, the number of axles, the vehicle length, and the vehicle width. (Appendix 3) The NP reader is A vehicle type discrimination system as described in Appendix 2, which calculates the detected vehicle speed based on an accumulation of multiple vehicle speeds obtained by the moving object detection until the vehicle passes the vehicle detector. (Appendix 4) The NP reader is a front NP reader installed at the front position; and a rear NP reader installed at a rear position in front of the vehicle detector, which, when receiving the vehicle detection signal, photographs the area behind the vehicle as a rear vehicle image and reads the NP of the vehicle from the rear vehicle image as NP information, The front NP reading device and the rear NP reading device are installed separately on the left and right sides of the vehicle detector, The front NP reader By performing image processing on the forward vehicle image, position information of an edge on the opposite side of the vehicle to the own device is calculated; The rear NP reader Calculating position information of an edge of the vehicle on the opposite side to the device by image processing the rear vehicle image; The data processing device includes: 4. The vehicle type discrimination system according to claim 2, wherein the vehicle width is calculated using position information of the left and right edges of the vehicle calculated by the front NP reading device and the rear NP reading device, respectively. (Appendix 5) The NP reader is an NP reading unit that reads the NP of the vehicle as NP information by image processing the image of the forward vehicle; a speed calculation unit that calculates the detected vehicle speed based on the moving object detection; a vehicle width measurement unit that measures the vehicle width by image processing the forward vehicle image; 5. The vehicle type discrimination system according to claim 2, further comprising a communication device that transmits the NP information, the detected vehicle speed, and the vehicle width to the data processing device. (Appendix 6) A vehicle type discrimination system for discriminating the type of vehicle entering a toll gate, the vehicle type discrimination system comprising a vehicle detector, an NP reader, an axle number sensor, and a data processing device, When the vehicle detector detects the vehicle, it transmits a vehicle detection signal indicating that the vehicle has been detected; The axle number sensor is installed at a position where the vehicle detector is installed, and is driven by the vehicle to acquire the number of axles of the vehicle and transmit the number of axles; The NP reader is An NP reading device that is installed in a position ahead of the vehicle detector in the direction of travel, and upon receiving the vehicle detection signal, photographs the area ahead of the vehicle as a forward vehicle image, reads the NP (Number Plate) of the vehicle from the forward vehicle image as NP information, calculates the speed of the vehicle as detected vehicle speed by detecting a moving object, calculates the vehicle length, which is the length of the vehicle, using the NP information and the detected vehicle speed, and transmits the NP information and information including the number of axles and the vehicle length to the data processing device, which determines the vehicle type. (Appendix 7) A vehicle type discrimination method for discriminating the vehicle type of a vehicle entering a toll gate, When the vehicle detector detects the vehicle, it transmits a vehicle detection signal indicating that the vehicle has been detected; An NP reading device is installed in a position ahead of the vehicle detector in the traveling direction, and when the vehicle detection signal is received, it takes an image of the area ahead of the vehicle as a forward vehicle image, reads the NP (Number Plate) of the vehicle from the forward vehicle image as NP information, and calculates the speed of the vehicle as a detected vehicle speed by detecting a moving object, and transmits the NP information and the detected vehicle speed. an axle number sensor is installed at a position where the vehicle detector is installed, and is stepped on by the vehicle to obtain the number of axles of the vehicle and transmit the number of axles; A vehicle type discrimination method in which a data processing device calculates the vehicle length, which is the length of the vehicle, using the vehicle detection signal and the detected vehicle speed, and discriminates the vehicle type of the vehicle using information including the NP information, the number of axles, and the vehicle length. (Appendix 8) A vehicle type discrimination system for discriminating the type of vehicle entering a toll gate, the vehicle type discrimination system comprising a vehicle detector, a NP reader, an axle number sensor, and a data processing device, includes a vehicle type discrimination program used in the NP reader, When the vehicle detector detects the vehicle, it transmits a vehicle detection signal indicating that the vehicle has been detected; The axle number sensor is installed at a position where the vehicle detector is installed, and is driven by the vehicle to acquire the number of axles of the vehicle and transmit the number of axles; The NP reader is installed in a position forward of the vehicle detector in the direction of travel, an NP reading process in which, upon receiving the vehicle detection signal, an image of a front vehicle is captured in front of the vehicle, and an NP (Number Plate) of the vehicle is read from the front vehicle image as NP information; a speed calculation process for calculating the speed of the vehicle as a detected vehicle speed by detecting a moving object; a vehicle width measurement process for measuring a vehicle width of the vehicle by image processing the forward vehicle image; a communication process of transmitting the NP information, the detected vehicle speed, and the vehicle width to a data processing device that calculates a vehicle length, which is the length of the vehicle, using the vehicle detection signal and the detected vehicle speed, and determines the vehicle type of the vehicle using the NP information, the number of axles, the vehicle length, and the vehicle width; A vehicle type discrimination program that causes the NP reader, which is a computer, to execute the above. [Explanation of symbols]

[0071] 10 vehicle, 21 vehicle detection signal, 22 camera, 31 NP information, 32 detected vehicle speed, 33 vehicle width, 34 number of axles, 41 vehicle length, 50 vehicle type, 80 signal line, 100 vehicle detector, 200 NP reader, 201 front NP reader, 202 rear NP reader, 210 NP acquisition unit, 220 speed calculation unit, 230 vehicle width measurement unit, 300 number of axles sensor, 400 data processing device, 500 vehicle type discrimination system, 909 electronic circuit, 910 processor, 921 memory, 922 auxiliary storage device, 930 input / output interface, 950 communication device.

Claims

1. In a vehicle type discrimination system that discriminates the type of vehicle entering a toll gate, a vehicle detector that, upon detecting the vehicle, transmits a vehicle detection signal indicating that the vehicle has been detected; an NP reader that is installed at a position ahead of the vehicle detector in the traveling direction, and that, upon receiving the vehicle detection signal, photographs an area ahead of the vehicle as a forward vehicle image, reads the NP (Number Plate) of the vehicle from the forward vehicle image as NP information, and calculates the speed of the vehicle as a detected vehicle speed by detecting a moving object, and transmits the NP information and the detected vehicle speed; an axle number sensor that is installed at a location where the vehicle detector is installed, and that acquires the number of axles of the vehicle when the vehicle runs over it, and transmits the number of axles; a data processing device that calculates a vehicle length, which is a length of the vehicle, using the vehicle detection signal and the detected vehicle speed, and determines a vehicle type of the vehicle using information including the NP information, the number of axles, and the vehicle length; A vehicle type identification system equipped with

2. The NP reader is measuring a vehicle width of the vehicle by image processing the image of the vehicle ahead, and transmitting the vehicle width; The data processing device includes:

2. The vehicle type discrimination system according to claim 1, wherein the vehicle type is discriminated using the NP information, the number of axles, the vehicle length, and the vehicle width.

3. The NP reader is The vehicle type discrimination system according to claim 2 , wherein the detected vehicle speed is calculated based on an accumulation of a plurality of vehicle speeds acquired by the moving object detection until the vehicle passes the vehicle detector.

4. The NP reader is a front NP reader installed at the front position; and a rear NP reader installed at a rear position in front of the vehicle detector, which, when receiving the vehicle detection signal, photographs the rear of the vehicle as a rear vehicle image and reads the NP of the vehicle from the rear vehicle image as NP information, The front NP reading device and the rear NP reading device are installed separately on the left and right sides of the vehicle detector, The front NP reader is calculating position information of an edge on the opposite side of the forward vehicle image in the vehicle by performing image processing on the forward vehicle image; The rear NP reader calculating position information of an edge on the opposite side of the rear vehicle image of the vehicle by performing image processing on the rear vehicle image; The data processing device includes:

4. The vehicle type discrimination system according to claim 2, wherein the vehicle width is calculated using position information of the left and right edges of the vehicle calculated by the front NP reading device and the rear NP reading device, respectively.

5. The NP reader is an NP reading unit that reads the NP of the vehicle as NP information by image processing the image of the forward vehicle; a speed calculation unit that calculates the detected vehicle speed based on the moving object detection; a vehicle width measurement unit that measures the vehicle width by image processing the forward vehicle image; 4. The vehicle type discrimination system according to claim 2, further comprising a communication device that transmits the NP information, the detected vehicle speed, and the vehicle width to the data processing device.

6. A vehicle type discrimination system for discriminating the type of vehicle entering a toll gate, the vehicle type discrimination system comprising a vehicle detector, an NP reader, an axle number sensor, and a data processing device, When the vehicle detector detects the vehicle, it transmits a vehicle detection signal indicating that the vehicle has been detected; The axle number sensor is installed at a position where the vehicle detector is installed, and is driven by the vehicle to acquire the number of axles of the vehicle and transmit the number of axles; The NP reader is An NP reading device that is installed at a position ahead of the vehicle detector in the direction of travel, and upon receiving the vehicle detection signal, photographs the area ahead of the vehicle as a forward vehicle image, reads the NP (Number Plate) of the vehicle from the forward vehicle image as NP information, calculates the speed of the vehicle as a detected vehicle speed by detecting a moving object, calculates the vehicle length, which is the length of the vehicle, using the NP information and the detected vehicle speed, and transmits the NP information and information including the number of axles and the vehicle length to the data processing device that determines the vehicle type.

7. A vehicle type discrimination method for discriminating the vehicle type of a vehicle entering a toll gate, When the vehicle detector detects the vehicle, it transmits a vehicle detection signal indicating that the vehicle has been detected; An NP reader is installed at a position ahead of the vehicle detector in the traveling direction, and upon receiving the vehicle detection signal, photographs the area ahead of the vehicle as a forward vehicle image, reads the NP (Number Plate) of the vehicle from the forward vehicle image as NP information, and calculates the speed of the vehicle as a detected vehicle speed by detecting a moving object, and transmits the NP information and the detected vehicle speed. an axle number sensor is installed at a position where the vehicle detector is installed, and is stepped on by the vehicle to obtain the number of axles of the vehicle and transmit the number of axles; A vehicle type discrimination method in which a data processing device calculates the vehicle length, which is the length of the vehicle, using the vehicle detection signal and the detected vehicle speed, and discriminates the vehicle type using information including the NP information, the number of axles, and the vehicle length.

8. A vehicle type discrimination system for discriminating the type of vehicle entering a toll gate, the vehicle type discrimination system comprising a vehicle detector, an NP reader, an axle number sensor, and a data processing device, includes a vehicle type discrimination program used in an NP reader, When the vehicle detector detects the vehicle, it transmits a vehicle detection signal indicating that the vehicle has been detected; The axle number sensor is installed at a position where the vehicle detector is installed, and is driven by the vehicle to acquire the number of axles of the vehicle and transmit the number of axles; The NP reader is installed in a position forward of the vehicle detector in the direction of travel, an NP reading process in which, upon receiving the vehicle detection signal, an image of a front vehicle is captured in front of the vehicle, and an NP (Number Plate) of the vehicle is read from the front vehicle image as NP information; a speed calculation process for calculating the speed of the vehicle as a detected vehicle speed by detecting a moving object; a vehicle width measurement process for measuring a vehicle width of the vehicle by image processing the forward vehicle image; a communication process of transmitting the NP information, the detected vehicle speed, and the vehicle width to a data processing device that calculates a vehicle length, which is a length of the vehicle, using the vehicle detection signal and the detected vehicle speed, and determines the vehicle type of the vehicle using the NP information, the number of axles, the vehicle length, and the vehicle width; A vehicle type discrimination program that causes the NP reader, which is a computer, to execute the above.

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