JP2020201725A - Vehicle tracking device, vehicle tracking method, and vehicle tracking program - Google Patents

Abstract

To provide a technique capable of accurately identifying a vehicle between points by processing frame images of a license plate of the vehicle which are captured at three or more points.SOLUTION: A vehicle tracking device 1 stores in a recognition result storage unit 13 a recognition result of recognizing a registration number inscribed on a license plate of a vehicle which passes a first point and a second point on a traveling passage and a recognition result of recognizing a series of designation numbers as a part of a registration symbol inscribed on the license plate of the vehicle passing an intermediate point which is positioned between the first point and the second point. An identification unit 11a uses the recognition result at each of the points to identify the vehicle between the points. The recognition result at the first point and the recognition result at the second point include time of passage of the vehicle.SELECTED DRAWING: Figure 4

Description

The present invention relates to a technique for tracking a vehicle traveling on a road.

Conventionally, there has been a system for tracking the running of a vehicle by installing cameras at a plurality of points on the road on which the vehicle travels (hereinafter referred to as vehicle detection points) and identifying the vehicle between the vehicle detection points (hereinafter referred to as a vehicle detection point). See Patent Document 1 etc.). This system has been put into practical use, for example, as a system for measuring travel time between two vehicle detection points.

Patent Document 1 processes a frame image of a vehicle at each vehicle detection point, recognizes a serial designation number written on the license plate of the vehicle, and collates the serial designation number to move a vehicle between vehicle detection points. It is a configuration to identify.

Further, as described in Patent Document 1, there are a plurality of vehicles having the same serial designation number. Therefore, if there are multiple vehicles with the same serial designation number in the vehicle group to be identified between the vehicle detection points, the vehicle can be identified between the vehicle detection points only by collating the serial designation numbers. It becomes inappropriate.

Patent Document 1 is configured to suppress improper identification of a vehicle between vehicle detection points by using vehicle type information in addition to a serial designation number.

Special Fair 5-86600 Gazette

However, on the license plate attached to the vehicle, in addition to the above-mentioned serial designation number, the area name, classification number, and hiragana are written. Here, the area name, classification number, hiragana, and serial designation number are collectively referred to as a registration code. The vehicle can be identified by the registration code printed on the license plate.

The character size of the area name, classification number, and hiragana written on the license plate is smaller than that of the serial designation number. There is also a license plate (region) where the region name is written in Chinese characters. For these reasons, the frame image used for recognizing the registration symbol has a higher required resolution than the case where only the serial designation number is recognized. In general, cameras capable of capturing higher resolution frame images are more expensive. Therefore, installing a camera capable of capturing a frame image having a resolution capable of appropriately recognizing the registration code at each vehicle detection point increases the cost for constructing the system.

An object of the present invention is to process a frame image of a vehicle license plate taken at three or more points to prevent improper identification of the vehicle between the points, and to construct a system. The purpose is to provide a technology that can suppress the increase in the number of vehicles.

The vehicle tracking device of the present invention is configured as shown below in order to achieve the above object.

The recognition result storage unit stores the first recognition result, the second recognition result, and the third recognition result. The first recognition result is the recognition result of the registration symbol written on the license plate of the vehicle that has passed the first point of the traveling path. The second recognition result is the recognition result of the registration code written on the license plate of the vehicle that has passed the second point of the traveling path. The third recognition result is the recognition result of the serial designation number written on the license plate of the vehicle that has passed the intermediate point of the traveling path.

From the upstream side of the runway, the first point, the intermediate point, and the second point are arranged in this order. Further, here, the area name, the classification number, the hiragana, and the serial designation number written on the license plate are collectively referred to as a registration code. In addition, the first recognition result includes the passing time of the vehicle at the first point. The second recognition result includes the passing time of the vehicle at the second point.

The identification unit identifies the vehicle between the points by using the first recognition result, the second recognition result, and the third recognition result.

The identification unit identifies the vehicle that has passed the first point and the vehicle that has passed the second point by collating the registration code. In addition, if there is a vehicle that has passed the intermediate point and cannot be identified as a vehicle that has passed the first point or the second point by collating the serial designation number, the identification unit will pass the vehicle at the first point. , And the passing time of the vehicle at the second point is used for identification.

In this way, vehicles that cannot be identified by collation of serial designation numbers are identified using the passing time of the first point and the passing time of the second point, so that the identification of the vehicle between the points is inappropriate. It can be suppressed.

Further, for the intermediate point, a camera having a resolution capable of capturing a frame image capable of recognizing a series of designated numbers can be used. That is, it is not necessary to use a camera having a resolution that can capture a frame image that can recognize the area name, classification number, and hiragana written on the license plate. Therefore, the increase in the cost for constructing the system can be suppressed.

In addition, if there is a vehicle that has passed the intermediate point and cannot be identified as a vehicle that has passed the first point or the second point by collating the serial designation number, the identification unit will pass the vehicle at the first point. , And, in addition to the passing time of the vehicle at the second point, the identification may be performed by using the distance between the first point and the intermediate point and the distance between the second point and the intermediate point. By also considering the distance between the first point and the intermediate point and the distance between the second point and the intermediate point, it is possible to further suppress the improper identification of the vehicle between the points.

Further, the travel time calculation unit may be provided to calculate the travel time of the vehicle between the two points based on the identification result of the vehicle at the two corresponding points by the identification unit.

Furthermore, by character recognition processing for the frame image of the license plate of the vehicle that passed the first point, the registration code written on the license plate was acquired as the first recognition result, and the vehicle that passed the second point. By character recognition processing for the frame image of the license plate of the vehicle, the registration code written on the license plate is acquired as the second recognition result, and the license plate of the vehicle that has passed the intermediate point is for the frame image of the image. The character recognition process may be configured to include a recognition result acquisition unit that acquires a series of designated numbers written on the license plate as a third recognition result.

According to the present invention, improper identification of the vehicle can be suppressed, and an increase in the cost for constructing the system can be suppressed.

It is a schematic diagram which shows the vehicle tracking system. It is a figure which shows the license plate. It is a block diagram which shows the structure of the main part of a point processing apparatus. It is a block diagram which shows the structure of the main part of a vehicle tracking device. FIG. 5 (A) shows a storage area for storing the recognition result received from the point processing device 2a, and FIG. 5 (B) shows a storage area for storing the recognition result received from the point processing device 2b. (C) shows a storage area for storing the recognition result received from the point processing device 2c, and FIG. 5 (D) shows a storage area for storing the recognition result received from the point processing device 2d. It is a figure which shows the tracking data of a vehicle. It is a flowchart which shows the operation of a point processing apparatus. It is a flowchart which shows the recognition result storage process. It is a flowchart which shows the identification process. It is the figure which showed the recognition result at each point in the order of passage of a vehicle. It is the figure which showed the recognition result at each point in the order of passage of a vehicle. 12 (A) and 12 (B) are diagrams for explaining the process of estimating the overtaking point. 13 (A) and 13 (B) are diagrams showing the identification of vehicles between points according to the estimated overtaking points. It is a block diagram which shows the structure of the main part of the vehicle tracking apparatus which concerns on a modification.

Hereinafter, embodiments of the present invention will be described.

<1. Application example>
FIG. 1 is a schematic view showing an application example of the vehicle tracking system according to this example. FIG. 2 is a diagram showing a license plate attached to a vehicle. The vehicle tracking system according to this example is a system for tracking a vehicle 100 traveling on a road (corresponding to a traveling road referred to in the present invention). The vehicle tracking system of this example acquires the tracking data of the vehicle 100 by detecting the vehicle 100 at a plurality of points and identifying the vehicle 100 between the points. From the tracking data of the vehicle 100, it is possible to obtain the congestion status of the vehicle 100 on the road, the travel time between two points, and the like.

In this example, the points A, B, C, and D shown in FIG. 1 are the passage detection points for detecting the passage of the vehicle 100. From the upstream side of the road, points A, B, C, and D are arranged in this order. In this example, the point A corresponds to the first point referred to in the present invention, and the point D corresponds to the second point referred to in the present invention. Further, the points B and C correspond to the intermediate points referred to in the present invention. That is, this example is an example in which two intermediate points are set between the first point and the second point referred to in the present invention.

The vehicle tracking system of this example is provided with corresponding cameras 6 (6a to 6d) and point processing devices 2 (2a to 2d) for each passage detection point. Each camera 6 is installed at an angle for photographing the license plate 101 attached to the vehicle 100 passing through the corresponding detection point. Specifically, the camera 6a is attached at an angle for photographing the license plate 101 of the vehicle 100 passing through the point A. The camera 6b is attached at an angle for photographing the license plate 101 of the vehicle 100 passing through the point B. The camera 6c is attached at an angle for photographing the license plate 101 of the vehicle 100 passing through the point C. The camera 6d is attached at an angle for photographing the license plate 101 of the vehicle 100 passing through the point D.

The registration symbol written on the license plate 101 will be briefly described with reference to FIG. The registration code written on the license plate 101 includes four items: a region name 111, a classification number 112, a hiragana 113, and a serial designation number 114. The area name is a place name indicating the competent transportation branch office written in kanji, hiragana, etc. The classification number 112 is a three-digit number indicating the type and use of the vehicle 100. Hiragana 113 is a single character and indicates private use, business use, or the like. The serial designation number 114 is a number having four or less digits.

In addition, the serial designation number 114 written on the license plate 101 has a larger character size than the area name 111, the classification number 112, and the hiragana 113. In other words, the area name 111, the classification number 112, and the hiragana 113 written on the license plate 101 have a smaller character size than the serial designation number 114.

As is well known, the vehicle 100 can be identified by the registration code (area name 111, classification number 112, hiragana 113, and serial designation number 114) written on the license plate 101. However, the vehicle 100 cannot be specified only by some items of the registration code (for example, a series designation number) written on the license plate 101.

The cameras 6 (6a to 6d) output the captured frame image to the associated point processing devices 2 (2a to 2d). If the license plate 101 of the vehicle 100 passing through the point A is imaged in the frame image captured by the camera 6a, the point processing device 2a has the registration code (area name 111,) written on the license plate 101. The classification number 112, the hiragana 113, and the serial designation number 114) are recognized. If the license plate 101 of the vehicle 100 passing through the point B is imaged in the frame image captured by the camera 6b, the point processing device 2b recognizes the serial designation number 114 indicated on the license plate 101. (Region name 111, classification number 112, and hiragana 113 are not recognized.) If the license plate 101 of the vehicle 100 passing through the point C is imaged in the frame image captured by the camera 6c, the point processing device 2c recognizes the serial designation number 114 indicated on the license plate 101. (Region name 111, classification number 112, and hiragana 113 are not recognized.) If the license plate 101 of the vehicle 100 passing through the D point is imaged in the frame image captured by the camera 6d, the point processing device 2d has a registration code (area name 111,) written on the license plate 101. The classification number 112, the hiragana 113, and the serial designation number 114) are recognized.

That is, the point processing devices 2a and 2d recognize the registration symbol written on the license plate 101, but the point processing devices 2b and 2c only recognize the serial designation number 114 written on the license plate 101. , Area name 111, classification number 112, and hiragana 113 are not recognized.

The point processing device 2 transmits the recognition result of the license plate 101 to the vehicle tracking device 1. This recognition result includes the acquisition time of the frame image used for recognizing the registration symbol or the serial designation number. The imaging time of this frame image is the passing time of the vehicle 100 at the corresponding passing detection point.

The recognition result transmitted by the point processing device 2a to the vehicle tracking device 1 corresponds to the first recognition result referred to in the present invention. The recognition result transmitted by the point processing devices 2b and 2c to the vehicle tracking device 1 corresponds to the third recognition result referred to in the present invention. The recognition result transmitted by the point processing device 2d to the vehicle tracking device 1 corresponds to the second recognition result referred to in the present invention.

The vehicle tracking device 1 identifies the vehicle 100 between the passing detection points by using the recognition results transmitted from the point processing devices 2a to 2d. Since the vehicle 100 can be identified by the registration code written on the license plate 101, the vehicle 100 that has passed the point A and the vehicle 100 that has passed the point D can be accurately identified. On the other hand, the vehicle 100 cannot be specified only by the serial designation number 114 (there are a plurality of vehicles 100 to which the license plate 101 having the same serial designation number 114 is attached). Therefore, if there are a plurality of vehicles 100 having the same serial designation number 114 in the vehicle group identified between the passage detection points, the license plate 101 having the same serial designation number 114 is attached. The vehicle 100 is identified by using the passing time of the vehicle 100 at the point A and the passing time of the vehicle 100 at the point D.

<2. Configuration example>
FIG. 3 is a block diagram showing a configuration of a main part of the point processing apparatus. The point processing devices 2 (2a to 2d) include a control unit 21, an image input unit 22, and a communication unit 23.

The control unit 21 controls the operation of each part of the point processing device 2 main body. Further, the control unit 21 has a character recognition unit 21a. The character recognition unit 21a will be described later.

The vehicle detection points (points A to D) frame images captured by the corresponding cameras 6 (6a to 6d) are input to the image input unit 22. The frame rate of the camera 6 is, for example, several tens of frames / sec (10 to 30 frames / sec). The point processing device 2 and the camera 6 may be connected by wire or wirelessly.

The communication unit 23 controls data communication with the vehicle tracking device 1 via the network 7.

Further, the character recognition unit 21a determines whether or not the license plate 101 of the vehicle 100 is imaged in the frame image of the camera 6 input to the image input unit 22. The character recognition unit 21a is. If the license plate 101 of the vehicle 100 is imaged, a character recognition process for recognizing the characters written on the license plate 101 is performed. However, the character recognition unit 21a of the point processing devices 2a and 2d recognizes the registration symbols (area name 111, classification number 112, hiragana 113, and serial designation number 114) written on the license plate 101. On the other hand, the character recognition unit 21a of the point processing devices 2b and 2c does not recognize the area name 111, the classification number 112, and the hiragana 113 written on the license plate 101, but recognizes only the serial designation number 114.

As described above, the point processing devices 2a to 2d are the same in terms of the configuration related to the hardware. However, the point processing devices 2a and 2d recognize the registration symbol written on the license plate 101, whereas the point processing devices 2a and 2d recognize only the serial designation number 114 written on the license plate 101. It differs in that it does. Therefore, the point processing devices 2b and 2c have a smaller processing load than the point processing devices 2a and 2d. Therefore, the point processing devices 2b and 2c may be configured by using a cheaper CPU having a processing speed slower than that of the point processing devices 2a and 2d.

The control unit 21 of the point processing device 2 is composed of a hardware CPU, a memory, and other electronic circuits. When the hardware CPU executes the character recognition program, it operates as the character recognition unit 21a. Further, the memory has an area for expanding the character recognition program and an area for temporarily storing data and the like generated when the character recognition program is executed. The control unit 21 may be an LSI in which a hardware CPU, a memory, and the like are integrated.

FIG. 4 is a block diagram showing a configuration of a main part of the vehicle tracking device. The vehicle tracking device 1 includes a control unit 11, a communication unit 12, a recognition result storage unit 13, a tracking data storage unit 14, and an output unit 15.

The control unit 11 controls the operation of each part of the vehicle tracking device 1 main body. Further, the control unit 11 has an identification unit 11a and a travel time calculation unit 11b. Details of the identification unit 11a and the travel time calculation unit 11b will be described later.

The communication unit 12 controls data communication with the point processing devices 2 (2a to 2d) via the network 7.

The recognition result storage unit 13 stores the recognition result received by the communication unit 12 in a cumulative manner for each point processing device 2. FIG. 5 is a diagram for explaining the recognition result stored in the recognition result storage unit. The recognition result storage unit 13 is provided with a storage area for storing the recognition result for each point processing device 2. FIG. 5 (A) shows a storage area for storing the recognition result received from the point processing device 2a, and FIG. 5 (B) shows a storage area for storing the recognition result received from the point processing device 2b. (C) shows a storage area for storing the recognition result received from the point processing device 2c, and FIG. 5 (D) shows a storage area for storing the recognition result received from the point processing device 2d.

As is clear from the above description, the recognition result received from the point processing device 2a is the recognition result of the vehicle 100 that has passed the point A (see FIG. 5A). The recognition result received from the point processing device 2b is the recognition result of the vehicle 100 that has passed the point B (see FIG. 5B). The recognition result received from the point processing device 2c is the recognition result of the vehicle 100 that has passed the point C (see FIG. 5C). Further, the recognition result received from the point processing device 2d is the recognition result of the vehicle 100 that has passed the point D (see FIG. 5D).

As shown in FIGS. 5A and 5D, the recognition results of the vehicle 100 passing through the points A and D are the area name 111, the classification number 112, which are indicated on the license plate 101 of the vehicle 100. It is the data associated with the hiragana 113, the serial designation number 114, and the passing time. Further, as shown in FIGS. 5B and 5C, the recognition result of the vehicle 100 passing through the points B and C is the serial designation number 114 and the serial designation number 114 indicated on the license plate 101 of the vehicle 100. It is the data associated with the passing time.

The tracking data storage unit 14 stores tracking data associated with the passing time of each passing detection point for each vehicle 100. FIG. 6 is a diagram showing vehicle tracking data. As shown in FIG. 6, this tracking data includes the area name 111, the classification number 112, the hiragana 113, the serial designation number 114, and the passing time of each passing detection point (passing time of point A, which is indicated on the license plate 101. It is the data associated with the passing time of the B point, the passing time of the C point, and the passing time of the D point). This tracking data is obtained by performing an identification process in which the identification unit 11a identifies the vehicle 100 that has passed each passage detection point (point A, point B, point C, and point D) between the points. The details of the identification process will be described later.

The recognition result storage unit 13 and the tracking data storage unit 14 may be non-volatile memories (EPROM, EEPROM, etc.), or may be auxiliary storage devices such as a hard disk drive and a solid state drive. Further, the recognition result storage unit 13 and the tracking data storage unit 14 may be composed of a single storage medium or different storage media.

The output unit 15 transfers the tracking data of the vehicle 100 stored in the tracking data storage unit 14 or the travel time between the passage detection points (travel time between the two points) to a higher-level device (not shown), if necessary. Output.

Next, the identification unit 11a and the travel time calculation unit 11b included in the control unit 11 will be described. The identification unit 11a identifies the vehicle 100 in which passage is detected between the passage detection points, based on the recognition result stored in the recognition result storage unit 13. The details of the identification process for identifying the vehicle 100 whose passage is detected between the passage detection points will be described later. Further, the travel time calculation unit 11b calculates the travel time between the two designated passage detection points based on the tracking data stored in the tracking data storage unit 14. These two passage detection points may be adjacent points (for example, points A and B) or may be non-adjacent points (for example, points A and C).

The control unit 11 of the vehicle tracking device 1 is composed of a hardware CPU, a memory, and other electronic circuits. When the hardware CPU executes the vehicle tracking program according to the present invention, it operates as the identification unit 11a and the travel time calculation unit 11b. Further, the memory has an area for developing the vehicle tracking program according to the present invention and an area for temporarily storing data and the like generated when the vehicle tracking program is executed. The control unit 11 may be an LSI in which a hardware CPU, a memory, and the like are integrated. Further, the hardware CPU is a computer that executes the vehicle tracking method according to the present invention.

<3. Operation example>
Hereinafter, the operations of the vehicle tracking device 1 and the point processing device 2 will be described. FIG. 7 is a flowchart showing the operation of the point processing device. A frame image captured by the corresponding camera 6 is input to the image input unit 22 of the point processing device 2. The point processing device 2 has an image memory (not shown) that temporarily stores the frame image input to the image input unit 22.

The point processing device 2 selects a frame image to be processed (s1). The frame image to be processed selected here is a frame image captured after a predetermined number of frames with respect to the previously selected frame image to be processed. The predetermined number of frames may be one frame or two or more frames.

The point processing device 2 determines whether or not the license plate 101 of the vehicle 100 is imaged in the processing target frame image selected in s1 (s2). In s2, it is determined whether or not the entire license plate 101 is imaged.

When the point processing device 2 determines in s2 that the license plate 101 is not imaged in the frame image to be processed, it returns to s1.

When the point processing device 2 determines that the license plate 101 is imaged in the frame image to be processed in s2, the point processing device 2 performs recognition processing (s3). The point processing devices 2a and 2d recognize the area name 111, the classification number 112, the hiragana 113, and the serial designation number 114 written on the license plate 101. The point processing devices 2b and 2d recognize the serial designation number 114 indicated on the license plate 101.

As described above, the recognition target of s3 in the point processing devices 2a and 2d is different from the recognition process of s3 in the point processing devices 2b and 2c.

The processing related to s1 to s3 is executed by the character recognition unit 21a.

The point processing device 2 transmits the recognition result of the recognition process related to s3 to the vehicle tracking device 1 (s4), and returns to s1. As recognition results, the point processing devices 2a and 2d record the recognition results of the area name 111, the classification number 112, the hiragana 113, and the serial designation number 114, and the recognition result including the imaging time of the frame image to be processed this time as the vehicle tracking device. Send to 1. As the recognition result, the point processing devices 2b and 2c transmit the recognition result of the serial designation number 114 and the recognition result including the imaging time of the frame image to be processed this time to the vehicle tracking device 1. The point processing device 2 executes communication with the vehicle tracking device 1 in the communication unit 23.

Here, the point processing device 2 transmits the recognition result to the vehicle tracking device 1 every time the recognition process related to s3 is executed. However, the recognition process related to s3 is performed for the preset number of vehicles 100. When executed, the recognition results of these vehicles 100 may be collectively transmitted to the vehicle tracking device 1. Further, the point processing device 2 may be configured to collectively transmit the recognition results of the vehicle 100 that has executed the recognition process related to s3 to the vehicle tracking device 1 at preset time intervals.

Next, the operation of the vehicle tracking device 1 will be described. First, the recognition result storage process executed by the vehicle tracking device 1 will be described. FIG. 8 is a flowchart showing the recognition result storage process. The vehicle tracking device 1 waits for the communication unit 12 to receive the recognition result from any of the point processing devices 2 connected via the network 7 (s11). When the vehicle tracking device 1 receives the recognition result, it determines the passage detection point of the recognition result received this time (s12). The process related to s12 is a process of determining the point processing device 2 that is the source of the recognition result received this time. As is well known, in data communication via the network 7, the transmission data includes data indicating the transmission source. The vehicle tracking device 1 stores the recognition result received this time in the recognition result storage unit 13 (s13), and returns to s11. In s13, the recognition result storage unit 13 stores the recognition result of the passage detection point determined in s12.

By executing the process shown in FIG. 8, the vehicle tracking device 1 can store the recognition result shown in FIG. 4 in the recognition result storage unit 13.

Next, the identification process of the vehicle tracking device 1 will be described. FIG. 9 is a flowchart showing the identification process. The vehicle tracking device 1 executes this identification process at a predetermined timing. For example, the vehicle tracking device 1 starts this identification process when a predetermined time (5 minutes, 10 minutes, etc.) has elapsed from the previous identification process.

The identification unit 11a executes this identification process. The identification unit 11a determines the target vehicle group this time (s21). In s21, the vehicle 100 whose timing of passing the point D is after the start of the previous identification process and before the start of the current identification process is determined as the target vehicle group of the current identification process.

The identification unit 11a identifies the vehicle 100 belonging to the target vehicle group determined in s21 between the points A and D (s22). In s22, the registration code (region name 111, classification number 112, hiragana 113, and serial designation number 114) written on the license plate 101 is used. Therefore, the vehicle 100 that has passed the point A and the vehicle 100 that has passed the point D can be accurately identified.

The identification unit 11a determines whether or not there is a vehicle 100 having the same serial designation number 114 among the vehicles 100 belonging to the target vehicle group determined in s21 (s23). In s23, it is determined whether or not there is a vehicle 100 having a duplicate series designation number among the vehicles 100 belonging to the target vehicle group determined in s21. If there is no vehicle 100 having the same serial designation number 114, the identification unit 11a identifies the vehicle 100 between the passage detection points by using the serial designation number 114 (s24). That is, in s24, if there is no vehicle 100 having a duplicate series designation number among the vehicles 100 belonging to the target vehicle group determined in s21 (in other words, each vehicle 100 belonging to the target vehicle group determined in s21). If the serial designation number 114 is different), the vehicle 100 is identified between the passage detection points using the serial designation number 114.

Further, if there is a vehicle 100 having the same serial designation number 114, the identification unit 11a has the same passage order of the vehicles 100 having the same serial designation number 114 at the A point and the same serial designation number 114 at the D point. It is determined whether or not the passing order of the vehicle 100 is the same (s25). When the identification unit 11a determines in s25 that the passing order is the same, the passing order of the vehicle 100 having the same serial designation number 114 is the same as the A point and the D point at the B point and the C point. (S26), the vehicle 100 is identified between the passage detection points. At this time, the identification unit 11a uses the serial designation number 114 to identify the other vehicle 100 in which the vehicle 100 having the same serial designation number 114 does not exist, between the passage detection points.

As an example, among the vehicle groups determined in s21, the vehicle 100 having the same serial designation number 114, the vehicle 100 having the registration code "Kyoto 550 ta 77", and the vehicle 100 having "Naniwa 381 only 77". The case where and exists will be described. Further, in this example, the passing order of the vehicles 100 having the same serial designation number 114 at the point A and the passing order of the vehicles 100 having the same serial designation number 114 at the point D are the same. In this case, the identification unit 11a determines that the passing order of these vehicles 100 is the same as that of the points A and D at the points B and C, and for example, as shown in FIG. 10, each passing. The vehicle 100 is identified between the detection points. FIG. 10 is a diagram showing the recognition results at each point in the order of passage of the vehicle. Further, “→” shown in FIG. 10 indicates a vehicle 100 identified between two adjacent points.

In the example shown in FIG. 10, at points A and D, the vehicle 100 whose registration code is "Kyoto 550 and 77" passes before the vehicle 100 whose registration code is "Naniwa 381 only 77". Therefore, the identification unit 11a states that the vehicle 100 whose registration code is "Kyoto 550 and 77" has passed before the vehicle 100 whose registration code is "Naniwa 381 only 77" at points B and C as well. Judgment and identification of vehicle 100 between points.

Further, when the identification unit 11a determines in s25 that the passing order is not the same, the identification of the vehicle 100 having the same serial designation number 114 is determined by the passing time at the A point, the passing time at the D point, and between the passing points. This is done using the distance (s27).

As an example, among the vehicle groups determined in s21, the vehicle 100 having the same serial designation number 114, the vehicle 100 having the registration code "Kyoto 550 ta 77", and the vehicle 100 having "Naniwa 381 only 77". The case where and exists will be described. Further, in this example, as shown in FIG. 11, the passing order of the vehicles 100 having the same series designation number 114 at the point A and the passing order of the vehicles 100 having the same series designation number 114 at the point D are the same. Not. Specifically, at point A, the vehicle 100 whose registration code is "Kyoto 550 ta 77" passes before the vehicle 100 whose registration code is "Naniwa 381 only 77", but at point D, it passes. The vehicle 100 whose registration code is "Naniwa 381 Mi 77" has passed before the vehicle 100 whose registration code is "Kyoto 550 Ta 77". In this case, the vehicle 100 whose registration code is "Naniwa 381 only 77" is overtaking the vehicle 100 whose registration code is "Kyoto 550 Ta 77" between points A and D. Therefore, if the vehicle 100 whose registration code is "Naniwa 381 only 77" does not estimate the point (overtaking point) overtaking the vehicle 100 whose registration code is "Kyoto 550 Ta 77", as shown in FIG. Vehicles 100 having the same designation number 114 cannot be identified between points.

In s27, the identification unit 11a estimates the overtaking point on the assumption that the vehicle 100 having the same serial designation number 114 has traveled at a constant speed from the point A to the point D. Specifically, as shown in FIG. 12, for each vehicle 100 having the same series designation number 114, a linear function of time and position is obtained, and the intersection is estimated to be an overtaking point. FIG. 12A is an example when the overtaking point is between the C point and the D point, and FIG. 12B is the case where the overtaking point is between the B point and the C point. This is an example.

As described above, at the points A and D, the vehicle 100 can be specified by the authentication of the registration code, and the passing time of each vehicle 100 is also obtained. Therefore, the above linear function is obtained.

In addition, 〇 and ◇ shown in FIG. 12 are passing times included in the recognition result of each point. Whether or not the linear function of time and position obtained for each vehicle 100 having the same serial designation number 114 is appropriate is determined by checking the passing time of the vehicle 100 having the same serial designation number 114 at points B and C. It may be judged by using.

The identification unit 11a identifies the vehicle 100 between the points according to the overtaking points estimated by the above process. FIG. 13A shows the vehicle identification result between the points when the overtaking point is between the points C and D. FIG. 13B shows the vehicle identification result between the points when the overtaking point is between the points B and C. 13 (A) and 13 (B) are also views showing the recognition results at each point in the order of passage of the vehicle, as in FIG. Further, “→” shown in FIGS. 13 (A) and 13 (B) indicates a vehicle 100 identified between two adjacent points.

The identification unit 11a generates the tracking data shown in FIG. 5 based on the identification result of the vehicle 100 in s24, s26, or s27, stores it in the tracking data storage unit 14 (s28), and ends this process.

Further, the vehicle tracking device 1 according to this example can calculate the travel time of the vehicle 100 between the two vehicle passage detection points based on the tracking data stored in the tracking data storage unit 14. The travel time calculation unit 11b calculates the travel time.

Specifically, the travel time calculation unit 11b determines that every 100 vehicles that have passed the downstream point during the most recent predetermined time (for example, 5 minutes and 10 minutes) between the two points for calculating the travel time. The time required for the vehicle 100 to travel between these two points is calculated. Then, the average traveling time of these vehicles 100 is calculated as the travel time between the two designated points at that time.

Further, the vehicle tracking device 1 uses the recognition result data of the vehicle 100 at each passage detection point to obtain the vehicle 100 that has flowed out at the branch road existing between the A point and the D point, the A point, and the D point. The vehicle 100 that has flowed in at the branch road existing between the two can also be identified.

As described above, in the vehicle tracking system according to this example, the cameras 6b and 6c installed at the points B and C that recognize only the serial designation number 114 are installed at the points A and D that authenticate the registration code. Since a camera having a resolution lower than that of the cameras 6a and 6d can be used, the cost for constructing the system can be suppressed. Further, the above-mentioned identification process can suppress a decrease in the identification accuracy of the vehicle 100 between the passage detection points.

In the above example, it is assumed that there are two points between the point A for authenticating the registration code and the point D for authenticating only the serial designation number 114, the point B and the point C. The number of points for authenticating only the serial designation number 114, which is provided between the point D and the point D, may be one or three or more.

<4. Modification example>
FIG. 14 is a block diagram showing a configuration of a main part of the vehicle tracking device according to another example. The vehicle tracking device 1A according to this example has almost the same configuration as the above example, except that the control unit 11 has a character recognition unit 11c. The character recognition unit 11c has the same configuration as the character recognition unit 21a of the point processing device 2 in the above example. In FIG. 14, the same reference numerals are given to the configurations similar to those shown in FIG.

The vehicle tracking device 1A of this another example is connected to the cameras 6 installed at each passage detection point (point A to D) via the network 7. That is, the point processing device 2 shown in the above example is not required.

Further, the communication unit 12 receives the frame image transmitted from the camera 6. The character recognition unit 11c recognizes the registration symbol written on the license plate 101 of the vehicle 100 being imaged for the frame image received from the cameras 6a and 6d. Further, the character recognition unit 11c recognizes the serial designation number written on the license plate 101 of the vehicle 100 being imaged for the frame image received from the cameras 6b and 6c. The character recognition unit 11c stores the recognition result of the license plate 101 in the recognition result storage unit 13.

Therefore, in the case of the vehicle tracking device 1A according to this other example, since the point processing device 2 does not have to be provided at the passage detection point, the cost for constructing the system can be further suppressed.

Further, in the above description, it is assumed that the B point and the C point are configured to recognize only the serial designation number 114 written on the license plate 101, but the B point and the C point are also registered symbols ( It may be configured to recognize the area name 111, the classification number 112, the hiragana 113, and the serial designation number 114). In this case, at a certain point, one or more of the area name 111, the classification number 112, or the hiragana 113 cannot be recognized due to the influence of disturbance such as shadows, and some items of the recognizable registration code are the points. If the vehicle 100 cannot be identified between them, the identification process shown in FIG. 9 may be executed to identify the vehicle 100 that has passed each point.

The present invention is not limited to the above-described embodiment as it is, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by an appropriate combination of a plurality of components disclosed in the above-described embodiment. For example, some components may be removed from all the components shown in the embodiments. In addition, components from different embodiments may be combined as appropriate. Further, in the flowchart used in the above description, the order of the steps may be changed as appropriate.

Further, the correspondence between the configuration according to the present invention and the configuration according to the above-described embodiment can be described as described in the following appendix.
<Additional notes>
As a result of the first recognition of recognizing the registration symbol written on the license plate (101) attached to the vehicle (100) that has passed the first point of the traveling path, the downstream side of the first point of the traveling path. The second recognition result of recognizing the registration symbol written on the license plate (101) attached to the vehicle (100) that has passed the second point located at, and the first point and the said on the traveling path. Recognized the serial designation number (114) which is a part of the registration symbol written on the license plate (101) attached to the vehicle (100) which passed the intermediate point located between the second point. A recognition result storage unit (13) that stores the third recognition result,
An identification unit (11a) for identifying a vehicle between points by using the first recognition result, the second recognition result, and the third recognition result is provided.
The first recognition result includes the passing time of the vehicle (100) at the first point.
The second recognition result includes the passing time of the vehicle (100) at the second point.
The identification unit (11a)
The vehicle (100) that has passed the first point and the vehicle (100) that has passed the second point are identified by collation of the registration code.
If there is a vehicle (100) that has passed the intermediate point and cannot be identified as a vehicle that has passed the first point or the second point by collation of the serial designation number (114), the vehicle (100) is described. A vehicle tracking device (1) that identifies using the passing time of the vehicle (100) at the first point and the passing time of the vehicle (100) at the second point.

1, 1A ... Vehicle tracking device 2 (2a to 2d) ... Point processing device 6 (6a to 6d) ... Camera 7 ... Network 11 ... Control unit 11a ... Identification unit 11b ... Travel time calculation unit 11c ... Character recognition unit 12 ... Communication Unit 13 ... Recognition result storage unit 14 ... Tracking data storage unit 15 ... Output unit 21 ... Control unit 21a ... Character recognition unit 22 ... Image input unit 23 ... Communication unit 100 ... Vehicle 101 ... Number plate 111 ... Area name 112 ... Classification number 113 ... Hiragana 114 ... Series designation number

Claims (6)

As a result of the first recognition result of recognizing the registration symbol written on the license plate attached to the vehicle that has passed the first point of the traveling path, the second point located on the downstream side of the first point of the traveling path. The second recognition result of recognizing the registration symbol written on the license plate attached to the vehicle that has passed through, and the intermediate point located between the first point and the second point of the traveling path. A recognition result storage unit that stores a third recognition result that recognizes a series of designation numbers that are part of the registration code written on the license plate attached to the passing vehicle, and a recognition result storage unit.
It is provided with an identification unit that identifies a vehicle between points by using the first recognition result, the second recognition result, and the third recognition result.
The first recognition result includes the passing time of the vehicle at the first point.
The second recognition result includes the passing time of the vehicle at the second point.
The identification unit
The vehicle that passed the first point and the vehicle that passed the second point were identified by collation of the registration code.
If there is a vehicle that has passed the intermediate point and cannot be identified as a vehicle that has passed the first point or the second point by collation of the serial designation number, the passing time of the vehicle at the first point, And a vehicle tracking device that identifies using the passing time of the vehicle at the second point. The identification unit
If there is a vehicle that has passed the intermediate point and cannot be identified as a vehicle that has passed the first point or the second point by collation of the serial designation number, the passing time of the vehicle at the first point, Identification is performed using the passing time of the vehicle at the second point, the distance between the first point and the intermediate point, and the distance between the second point and the intermediate point.
The vehicle tracking device according to claim 1. The vehicle tracking device according to claim 1 or 2, further comprising a travel time calculation unit that calculates the travel time of a vehicle between two points based on the identification result of the vehicle at the two corresponding points by the identification unit. .. By character recognition processing for the frame image of the license plate of the vehicle that passed the first point, the registration symbol written on the license plate was acquired as the first recognition result and passed through the second point. By character recognition processing for the frame image in which the license plate of the vehicle was imaged, the registration symbol written on the license plate was acquired as the second recognition result, and the license plate of the vehicle that passed the intermediate point was imaged. The vehicle tracking device according to any one of claims 1 to 3, further comprising a recognition result acquisition unit that acquires a series of designated numbers written on the license plate as the third recognition result by character recognition processing on the frame image. .. As a result of the first recognition result of recognizing the registration symbol written on the license plate attached to the vehicle that has passed the first point of the running path, the second point located on the downstream side of the first point of the running path. The second recognition result of recognizing the registration symbol written on the license plate attached to the vehicle that has passed through, and the intermediate point located between the first point and the second point of the travel path. The first step of recognizing the serial designation number which is a part of the registration symbol written on the license plate attached to the passing vehicle and storing the third recognition result in the recognition result storage unit, and
It comprises an identification step of identifying a vehicle between points using the first recognition result, the second recognition result, and the third recognition result.
The first recognition result includes the passing time of the vehicle at the first point.
The second recognition result includes the passing time of the vehicle at the second point.
The identification step
The vehicle that passed the first point and the vehicle that passed the second point were identified by collation of the registration code.
If there is a vehicle that has passed the intermediate point and cannot be identified as a vehicle that has passed the first point or the second point by collation of the serial designation number, the passing time of the vehicle at the first point, And a vehicle tracking method, which is a step of identifying using the passing time of the vehicle at the second point. As a result of the first recognition result of recognizing the registration symbol written on the license plate attached to the vehicle that has passed the first point of the running path, the second point located on the downstream side of the first point of the running path. The second recognition result of recognizing the registration symbol written on the license plate attached to the vehicle that has passed through, and the intermediate point located between the first point and the second point of the travel path. The first step of recognizing the serial designation number which is a part of the registration symbol written on the license plate attached to the passing vehicle and storing the third recognition result in the recognition result storage unit, and
Using the first recognition result, the second recognition result, and the third recognition result, a computer is made to perform an identification step of identifying a vehicle between points.
The first recognition result includes the passing time of the vehicle at the first point.
The second recognition result includes the passing time of the vehicle at the second point.
The identification step
The vehicle that passed the first point and the vehicle that passed the second point were identified by collation of the registration code.
If there is a vehicle that has passed the intermediate point and cannot be identified as a vehicle that has passed the first point or the second point by collation of the serial designation number, the passing time of the vehicle at the first point, And a vehicle tracking program, which is a step of identifying using the passing time of the vehicle at the second point.

Images