JP7139843B2 - Mobile object information detection device, mobile object information detection method, and program - Google Patents

Description

The present invention relates to a moving body information detecting apparatus, a moving body information detecting method, and a program for detecting information of a plurality of moving bodies moving in the same direction in a predetermined detection target area.

Conventionally, radio waves (electromagnetic waves) called microwaves with a frequency of 300 MHz to 300 GHz (wavelength: about 1 mm to 1000 mm) are transmitted toward the object to be measured, the reflected wave from the object to be measured is received, and the reflected wave There is known a technique for measuring information on physical property values of an object to be measured by analyzing . In general, when a transmitted microwave reaches a target, it undergoes effects such as scattering, refraction, attenuation, and delay (phase shift) depending on the material, size, and surface shape of the target. By receiving the reflected wave that has undergone such action and comparing its amplitude and phase information with the transmitted wave, we can obtain the material, shape, size, distance, and position of the object as information on the physical properties of the object. , and their temporal changes can be measured without contact.

A vehicle information detection system is known that detects vehicle information such as the position, traveling speed, and length (length in the traveling direction) of a vehicle traveling on a road using such measurement technology. As an example of the vehicle information detection system, a traveling vehicle counting device that measures the number of vehicles traveling on a road using a Doppler detection sensor (for example, Doppler radar) is known (see Patent Document 1). Vehicle information detection systems of this type have so far used radio waves in the so-called 24 GHz band (Japan: 24.05 GHz to 24.25 GHz, Europe: 24.0 GHz to 24.25 GHz) in the microwave frequency band. rice field. Radio waves in the 24 GHz band are widely used in Japan's Intelligent Transport Systems (ITS), and are also widely used in Western countries. In Japan, the use of radio waves in the so-called 76 GHz band (76 GHz to 77 GHz) for general business use has already been approved. use is also permitted.

Japanese Unexamined Patent Application Publication No. 2011-204138

In recent years, there has been a demand for more accurate vehicle information detection processing in intelligent transportation systems. However, in the conventional vehicle information detection system, since the distance resolution in the width direction of the road is low, when two vehicles run side by side on a road with multiple lanes, these two vehicles are determined to be one vehicle. False positives may occur. Specifically, when two vehicles that entered the vehicle detection area separately and had different speeds lined up side by side in the vehicle detection area, they lined up side by side even though each vehicle had been identified individually immediately after entering. In some cases, two vehicles are determined to be one, resulting in a problem that the number of vehicles in the vehicle detection area cannot be accurately counted. In contrast, by applying a hardware configuration using high-performance ICs and a unique algorithm that performs complex arithmetic processing, it is possible to increase the distance resolution in the width direction of the road and reduce erroneous counts. However, this not only increases the cost of the hardware configuration, but also increases the processing load on the computing unit that performs processing based on the unique algorithm.

An object of the present invention is to run parallel to the traveling direction without using a high-performance IC and without performing complicated arithmetic processing even if the distance resolution in the width direction that intersects the traveling direction is low. It is an object of the present invention to provide a moving body information detecting device, a moving body information detecting method, and a program capable of holding the separation state of each moving body after individually specifying the moving bodies.

A moving object information detection device according to one aspect of the present invention detects information on a plurality of moving objects moving in the same direction in a predetermined detection area. The moving body information detection device includes a moving body identification unit, a first determination unit, and a second determination unit. The moving body identifying unit analyzes the distribution of reflected waves of radio waves periodically transmitted from the downstream side of the traveling direction of the moving body toward the detection area for each cycle, and determines that the distribution density is equal to or greater than a predetermined threshold. group is specified as moving body information indicating one moving body. The first determination unit determines whether or not the two groups corresponding to the two pieces of mobile information individually identified by the mobile identification unit are integrated into one. The second determination unit determines, when the first determination unit determines that the two groups have been integrated into one, the two movements indicated by the two pieces of moving body information before determination by the first determination unit. Based on the moving direction of each object and the position in the width direction intersecting the moving direction, it is determined whether or not to maintain the separation state of the two moving object information.

Because of this configuration, even if the distance resolution in the width direction is low, when each moving body is individually identified in the detection area, one moving body catches up with the other moving body after that. moving bodies are considered to be one, the separated state of each moving body once individually specified can be maintained. As a result, it is possible to accurately count the number of two moving bodies that actually exist. In other words, even if the distance resolution in the width direction is low because a high-performance IC is not used and a high-precision algorithm that involves complicated arithmetic processing is not used, according to the present invention, It is possible to accurately count a plurality of moving objects traveling in the detection area.

The second determination unit determines whether the two moving objects indicated by the two moving object information before determination by the first determination unit are adjacent in the width direction, and Preferably, it is determined to maintain the separation state of the two pieces of mobile information when the distance between the directions is gradually decreasing.

This makes it possible to improve the accuracy of the determination processing by the second determination unit, that is, the determination processing for maintaining the separation state of the two pieces of moving body information.

When the second determination unit determines that the separation state of the two pieces of moving object information is to be maintained, the moving object specifying unit divides the distribution into two in the width direction, and divides the distribution into two pieces of the moving object corresponding to each distribution. Identify information.

Thereby, it is possible to concretely maintain the separated state of the two pieces of mobile information.

The moving body information detection apparatus of the present invention further includes a counting unit that counts the number of the moving body information in a counting area determined downstream in the traveling direction in the detection area as the number of the moving bodies.

Further, the mobile object information detection apparatus of the present invention further comprises an identification setting unit that sets an identification code to the mobile object information specified by the mobile object specifying unit. In this case, the counting unit detects the identification code of the moving body information in the counting area, and counts the number of detected identification codes as the number of the moving bodies. As a result, the number of moving bodies can be counted more accurately.

Further, the moving body information detection apparatus of the present invention further includes an output section for externally outputting the moving body information specified by the moving body specifying section. This makes it possible to externally output the moving body information such as position information (object information), speed information, size, and number of the moving bodies, for example.

According to another aspect of the present invention, a moving object information detection method detects information on a plurality of moving objects moving in the same direction in a predetermined detection area. The mobile information detection method includes a mobile identification step, a first determination step, and a second determination step. The moving object identification method analyzes the distribution of reflected waves of radio waves periodically transmitted from the downstream side of the movement direction of the moving object toward the detection area for each period, and determines that the distribution density is equal to or greater than a predetermined threshold. group is specified as moving body information indicating one moving body. The first determination step determines whether or not the two groups respectively corresponding to the two pieces of mobile body information individually specified by the mobile body specifying unit are integrated into one. In the second determination step, when it is determined in the first determination step that the two groups have been integrated into one, the two movements indicated by the two pieces of moving body information before determination in the first determination step are determined. Based on the moving direction of each object and the position in the width direction intersecting the moving direction, it is determined whether or not to maintain the separation state of the two moving object information.

The present invention can also be regarded as a program for causing a computer to execute each step of the vehicle information detection method, or a computer-readable recording medium in which such a program is non-temporarily recorded.

According to the present invention, even when moving object information is detected using radio waves with low distance resolution in the width direction that intersects the traveling direction, each moving object that runs parallel to the traveling direction is identified individually. It is possible to maintain the separation state of the moving body.

FIG. 1 is a schematic diagram showing an example of a vehicle running state to which a vehicle information detection device according to an embodiment of the invention is applied. FIG. 2 is a plan view showing vehicle detection areas and vehicle counting areas in the embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of the vehicle information detection device and radar sensor in FIG. FIG. 4 is a schematic diagram showing an example of distribution of reflected wave signals from two vehicles spaced apart in the running direction. FIG. 5 is a schematic diagram showing an example of the distribution state of reflected wave signals from two vehicles adjacent to each other in the running direction. FIG. 6 is a diagram showing an example of the distribution of the reflected signal in the width direction of the road, (A) shows an example of the distribution curve in the width direction passing through the center of each distribution range in FIG. 4, and (B) shows FIG. 6 is a schematic diagram showing an example of a distribution curve in the width direction passing through the center of the distribution range of FIG. 5; FIG. 7 is a flow chart showing an example of the procedure of vehicle information detection processing executed by the control section of the vehicle information detection device according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. It should be noted that the embodiment described below is merely an example that embodies the present invention, and does not limit the technical scope of the present invention.

Hereinafter, a vehicle information detection device 10 (an example of a moving body information detection device of the present invention) according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG.

FIG. 1 is a schematic diagram for explaining a running state of a vehicle 30 (an example of a moving body of the present invention) such as an automobile to which the vehicle information detection device 10 is applied. FIG. 2 is a plan view showing a road 40 on which the vehicle 30 travels. FIG. 3 is a block diagram showing configurations of the vehicle information detection device 10 and the radar sensor 20. As shown in FIG.

As shown in FIG. 1, the vehicle information detection device 10 is attached to a pillar 25 installed in a roadside area of a road 40. As shown in FIG. A radar sensor 20 is mounted near the top of the pillar 25 to emit a radio wave signal SG1 for vehicle information detection toward a predetermined detection area 45 on the road 40 .

In this embodiment, as a traffic environment to which the vehicle information detection device 10 is applied, a road 40 having two lanes 40A and 40B on which a vehicle 30 can travel side by side in the same direction toward the radar sensor 20 is exemplified. . A detection area 45 (an area surrounded by a dashed line in FIG. 1) for detecting the vehicle 30 is defined on the road 40 . The detection area 45 is located between the measurement start position P1 and the radar sensor 20 from the measurement start position P1 that is determined upstream of the radar sensor 20 in the traveling direction D11 of the vehicle 30 (an example of the traveling direction of the present invention). This is the area that reaches the determined measurement end position P2. The vehicle information detection device 10 is configured to be able to detect vehicle information (number count, position, speed, vehicle length, etc.) of a plurality of vehicles 30 traveling in the detection area 45 in the traveling direction D11.

Here, as shown in FIG. 2, the distance l1 from the measurement start position P1 to the measurement end position P2 in the detection area 45, that is, the distance L1 along the running direction D10 in the detection area 45 is approximately 150 m. Also, in plan view, the distance L2 from the measurement end position P2 to the radar sensor 20 is approximately 20 m. The vehicle information detection device 10 is not limited to the traffic environment described above, and can be applied to a traffic environment in which a plurality of vehicles run side by side on a road with three or more lanes.

The radar sensor 20 is installed at a predetermined height from the road surface of the road 40 . The radar sensor 20 is electrically connected to the vehicle information detection device 10 wirelessly or by wire. As shown in FIG. 3, the radar sensor 20 includes an antenna 21, a transmission circuit 22 that outputs a radio wave signal SG1 to the antenna 21, a reception circuit 23 that inputs a signal from the antenna 21 as a reflected wave signal SG2, a transmission circuit 22 and It has a well-known configuration including an oscillator circuit 24 for supplying a sine wave signal of 24 GHz band to each receiving circuit 23 . The receiving circuit 23 is provided with an amplifying circuit (not shown) and an AD converting circuit (not shown), which amplifies the received reflected wave signal SG2, converts it into a digital signal, and sends it to the control unit 12, which will be described later. Output. The antenna 21 is provided with a transmission/reception switching circuit (duplexer circuit), so that it serves both for transmission and reception. As the radar sensor 20, an FMCW (Frequency Modulation Continuous Wave) type radar sensor, a Doppler type radar sensor, a phase type radar sensor, or the like can be applied.

The radar sensor 20 periodically transmits a radio signal SG1 toward a detection area 45 (see FIG. 1) defined on the road 40, and the transmitted radio signal SG1 is reflected on the surface of the vehicle 30 and the road surface of the road 40. Then, the reflected wave signal SG2 returned to the antenna of the radar sensor 20 is received. Such transmission/reception is performed every predetermined period T. As shown in FIG. That is, the radar sensor 20 receives the reflected wave signal SG2 from the entire detection area 45 every period T and samples the reflected wave signal SG2. The sampled reflected wave signal SG2 is digitized in the receiving circuit 23 and then output to the later-described control unit 12 provided in the vehicle information detection device 10 . Here, the period T is, for example, 1/f[s] when the frequency f is several Hz to several tens of Hz. That is, scanning of the radio signal SG1 is performed several times to several tens of times per second.

The radio wave signal SG1 emitted by the radar sensor 20 is a radio wave belonging to the so-called quasi-millimeter wave (20 GHz to 30 GHz radio wave). 24.05 GHz to 24.25 GHz) radio waves. Further, the radio signal SG1 has directivity characteristics with a directivity width of Δθ1 in the width direction D12 (that is, the horizontal direction) of the road 40 and a predetermined angular width of θ2 in the vertical direction. In this embodiment, the height position of the radar sensor 20 is set at a position where the radio wave signal SG1 having the angle θ2 can irradiate the range of the detection area 45 in the traveling direction D11.

Further, the radar sensor 20 irradiates the entire detection area 45 in the width direction D12 with the radio signal SG1 every period T by scanning the radio signal SG1 in the width direction D12 by the directional width Δθ1. Therefore, when the vehicle 30 passes the measurement start position P1 and enters the detection area 45 , the antenna 21 of the radar sensor 20 receives the reflected wave signal SG2 that is reflected by the vehicle 30 and returned to the radar sensor 20 . Here, the scanning angle .theta.1 in the width direction D12 is set, for example, to several times the directional width .DELTA..theta.1. Note that the radio signal SG1 may have a directional characteristic that can irradiate the entire detection area 45 defined on the road surface of the road 40 with a single transmission. In this case, the radar sensor 20 does not need to scan the radio wave signal SG1 in the width direction D12.

A counting area 46 for counting the number of passing vehicles 30 is defined in the detection area 45 . The counting area 46 is defined at the downstream end of the detection area 45 in the running direction D11. As will be described later, the vehicle information detection device 10 counts the number of vehicles 30 that have passed through the counting area 46 when the vehicles 30 pass through the counting area 46 .

As shown in FIG. 3, the vehicle information detection device 10 includes a control section 12, a storage section 13, and a communication section 14 (an example of the output section of the present invention). In addition to the radar sensor 20 described above, the vehicle information detection device 10 is also connected to the management server 15 through the network N1.

The communication unit 14 is a communication interface, connects the vehicle information detection device 10 to the network N1 by wire or wirelessly, and performs data communication according to a predetermined communication protocol with the management server 15 via the network N1. . The communication unit 14 transmits vehicle information such as position information (object information), speed information, vehicle size, count information of the vehicle 30, etc. of the vehicle 30 identified by the vehicle identification unit 123 described later in the vehicle information detection device 10 through the network N1. output to the management server 15 via the

The management server 15 is a server device that manages vehicle information of the vehicle 30 sent from the vehicle information detection device 10 . In this embodiment, the vehicle information detection device 10 constitutes a vehicle information detection system 100 as a whole by being communicably connected to the management server 15 and the radar sensor 20 . The management server 15 has a display unit such as a monitor for displaying vehicle information, and the vehicle information is displayed on the display unit so that the position of the vehicle 30 on the road 40 can be visually recognized. In this embodiment, the configuration in which the vehicle information detection device 10 is communicably connected to the management server 15 is illustrated, but the vehicle information detection device 10 may be implemented by the management server 15 .

The storage unit 13 is a non-volatile storage medium such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive). In the storage unit 13, a control program for causing the control unit 12 to execute various processes, each threshold value used in the vehicle information detection process described later executed by the vehicle information detection device 10, and the radar sensor 20 sent from the The distribution of the reflected wave signal SG2, various vehicle information specified by the vehicle information detection device 10, and the like are stored.

The control unit 12 has control devices such as a CPU, ROM, and RAM. The ROM is a non-volatile storage medium in which control programs such as BIOS and OS for causing the CPU to execute various processes are stored in advance. The RAM is a volatile or non-volatile storage medium that stores various information, and is used as a temporary storage memory (work area) for various processes executed by the CPU. The control unit 12 controls the vehicle information detection device 10 by causing the CPU to execute various control programs pre-stored in the ROM or storage unit 13 . The CPU that executes the control program, or the control unit 12 that includes the CPU, is an example of the computer of the present invention.

As shown in FIG. 3, the control unit 12 includes a transmission control unit 121, a target measurement unit 122, a vehicle identification unit 123 (an example of the mobile object identification unit of the present invention), and a first determination unit 124 (first mobile object identification unit of the present invention). an example of a determination unit), a second determination unit 125 (an example of a second determination unit of the present invention), an ID setting unit 126 (an example of an identification setting unit of the present invention), a tracking processing unit 127, a vehicle counting unit 128 (an example of the (an example of a counting unit of )) and various other processing units. The control unit 12 functions as the various processing units by executing various processing such as vehicle information detection processing in accordance with the control program by the CPU. Part or all of the processing units included in the control unit 12 may be configured by electronic circuits. Further, the control program may be a program for causing a plurality of processors to function as the various processing units.

The transmission control unit 121 generates a transmission trigger for each period T described above and outputs it to the transmission circuit 22 of the radar sensor 20 . Upon receiving the transmission trigger, the transmission circuit 22 sends out the radio signal SG1 to the antenna 21, radiates the radio signal SG1 from the antenna 21, and transmits the radio signal in the width direction D12 by the directional width Δθ1 (see FIG. 1). Scan SG1.

The target measuring unit 122 extracts a reflected wave signal SG2 having a predetermined level or higher from the plurality of digitized reflected wave signals SG2 output from the receiving circuit 23 as a target signal. In general, when the reflected wave signal SG2 reflected by the vehicle 30 and the reflected wave signal SG2 reflected by the road surface are compared, the intensity of the reflected wave signal SG2 reflected by the vehicle 30 is higher. Therefore, the predetermined level is set to a threshold that can distinguish only the reflected wave signal SG2 reflected by the vehicle 30 from a plurality of received reflected wave signals SG2 (digital signals). Also, the reflected wave signal SG2 reflected by the vehicle 30 is affected by scattering, refraction, attenuation, delay (phase shift), and the like depending on the shape of the surface of the vehicle 30 . Therefore, each time the radio signal SG1 is transmitted, a plurality of reflected wave signals SG2 are received by the receiving circuit 23, and from the plurality of reflected wave signals SG2, a plurality of target signals having an intensity equal to or higher than a predetermined level are obtained. is extracted. Hereinafter, a plurality of target signals extracted in this manner will be referred to as target signal SG2.

In addition, the target measuring unit 122 converts from the radio wave propagation time (delay time) from the time of transmitting the radio signal SG1 to the time of receiving the reflected wave signal SG2, and converts the signal from the vehicle 30 reflecting the radio signal SG1 to the radar sensor 20 Measure the distance to Furthermore, the target measuring unit 122 measures the position of the vehicle 30 in the detection area 45 from information such as the measured distance, the scanning angle at the time of transmission of the radio signal SG1, and the predetermined angle θ2 (see FIG. 1). . The position of the vehicle 30 is obtained as XY coordinates with the detection area 45 as the XY plane, with the width direction D12 as the X axis and the traveling direction D11 as the Y axis, as shown in FIG. This coordinate information is obtained and stored in the storage unit 13 each time the cycle T elapses. Information such as the distance and position to the vehicle 30 may be obtained by obtaining the frequency difference between the radio wave signal SG1 at the time of transmission and the reflected wave signal SG2 at the time of reception and analyzing this frequency difference.

FIG. 4 shows the distribution state in the XY plane of a plurality of target signals SG2 based on the reflected wave signals SG2 from the respective vehicles 30 while the vehicles 30 (30A, 30B) are running at the positions shown in FIG. FIG. 4 is a diagram showing; In FIG. 2, the two vehicles 30A and 30B are separated by a distance DS along the traveling direction D11. In FIG. 4 , each black dot indicates the target signal SG2, and the positions of the dots indicate reflection positions that can be estimated to have been reflected on the surface of each vehicle 30. In FIG. As shown in FIG. 4, the distribution density of the target signal SG2 is high in the ranges 31A and 31B (see the dashed line enclosure) corresponding to the actual position of the vehicle 30 (see FIG. 2). On the other hand, as described above, the reflected wave signal SG2 is affected by scattering, refraction, attenuation, delay (phase shift), and the like depending on the shape of the surface of the vehicle 30. FIG. Therefore, dots indicating the target signal SG2 also appear at positions outside the range 31A corresponding to the actual position of the vehicle 30 in the width direction D12, although the distribution density is low.

The vehicle identification unit 123 performs a process of identifying object information (an example of mobile object information of the present invention) indicating one vehicle 30 from the plurality of target object signals SG2 extracted by the target object measurement unit 122 . Specifically, based on the distribution of the plurality of reflected wave signals SG2 shown in FIG. 4, one cluster (group) having a distribution density greater than a predetermined threshold value TH (see FIG. 6A) is divided into one vehicle. Group processing for specifying object information indicating 30 is performed. Here, FIG. 6A is a diagram showing an example of the distribution state of the target signal SG2 in the width direction D12 of the road 40. The distribution in the width direction D12 passing through the respective centers of the ranges 31A and 31B in FIG. Curves W11 and W12 are shown. As shown in FIG. 6A, the portion of the distribution curve W11 above the threshold value TH corresponds to the range 31A. Also, the portion of the distribution curve W12 that is equal to or greater than the threshold TH corresponds to the range 31B. In the example shown in FIG. 4, the position information indicating the center position of the portion of range 31A is specified as the object information indicating vehicle 30A. Position information indicating the center position of the portion of range 31B is specified as object information indicating vehicle 30B. That is, each piece of object information is position information indicating the measured position of the vehicle 30 in the detection area 45 and is represented by XY coordinates. Each piece of object information is obtained and stored in the storage unit 13 each time the cycle T elapses.

The ID setting unit 126 gives the object information specified by the vehicle specifying unit 123 an identification ID (an example of the identification code of the present invention) for distinguishing the object information from other object information. For example, the ID setting unit 126 arbitrarily issues a unique identification ID, and stores the identification ID in the storage unit 13 while being associated with the object information.

The tracking processing unit 127 compares each piece of object information (position information) specified for each cycle T to determine whether the object information for each cycle T indicates the same measured position of the vehicle 30. . For example, the tracking processing unit 127 considers the period T of transmitting the radio signal SG1, the directional width Δθ1, or the average traveling speed, etc., the positional interval ΔDS of each object information, the angular direction difference with respect to the radar sensor 20 , the difference in running speed, etc., is within a predetermined range in which the same vehicle 30 can be evaluated. Note that the traveling speed can be calculated based on the position of the object information determined to be the same by the tracking processing of the time before last and the time of the previous time. When it is determined that each piece of object information indicates the same vehicle 30, a process of inheriting (giving) the identification ID that has already been given to the object information specified later is performed. Such processing is performed each time the cycle T elapses, and the object information in the storage unit 13 is updated.

The vehicle counting unit 128 counts the number of vehicles 30 when passing through the counting area 46 defined on the downstream side of the detection area 45 in the traveling direction D11. Specifically, when the position indicated by the object information specified by the vehicle specifying unit 123 is within the counting area 46, the identification ID associated with the object information is detected, and the number of times of detection is counted as the number of vehicles 30. count as This count value is stored in the storage unit 13 and output to the management server 15 .

By the way, the radio signal SG1 used in the vehicle information detection device 10 is in the so-called 24 GHz band. In the conventional vehicle information detection device that uses radio waves of the 24 Ghz band, the distance resolution in the width direction D12 of the road 40 is relatively low. Therefore, when the vehicles 30A and 30B run side by side on the road 40 having a plurality of lanes 40A and 40B, the two vehicles 30A and 30B may be misdetected as one vehicle. There is Specifically, when two vehicles 30A and 30B that have separately entered the detection area 45 and have different speeds are lined up side by side in the detection area 45, the vehicles 30A and 30B are individually identified immediately after entering. Otherwise, the two vehicles 30A and 30B are determined to be one vehicle when they are lined up side by side. Such a problem does not always occur, for example, when the vehicles 30A and 30B run side by side in the detection area 45 at the same speed. For example, when one vehicle 30A is a large vehicle such as a trailer or a bus, and the other vehicle 30B is a compact vehicle or a standard-sized vehicle, the two vehicles 30A will have to wait until the vehicle 30B catches up with the vehicle 30A and overtakes it. , 30B are determined to be one vehicle, and the above-described erroneous counting may occur.

For example, when the vehicle 30 (30A, 30B) shown in FIG. 2 moves in the traveling direction D11, and after a predetermined period of time, the two vehicles 30A, 30B line up side by side within the detection area 45 as indicated by the dashed line in FIG. 5, the distribution density of the target signal SG2 in the intermediate area between the vehicle 30A and the vehicle 30B in the width direction D12 increases, and the distribution density in the intermediate area reaches a predetermined threshold value TH (FIG. 6(B )) may exceed. In this case, not only the range corresponding to the actual position of the vehicle 30 but also the range 31C including the intermediate region between the vehicle 30A and the vehicle 30B form one cluster (group) larger than the predetermined threshold value TH. In the process, this range 31C is identified as object information indicating one vehicle 30. FIG. If such erroneous identification is performed, the number of vehicles 30 cannot be accurately counted.

On the other hand, the vehicle information detection device 10 of the present embodiment uses the radio signal SG1 having a low range resolution in the width direction D12 that intersects the running direction D11. It is configured so that the separated state of each vehicle 30 can be maintained even when both are integrated after being specified individually.

Specifically, the control unit 12 includes the first determination unit 124 and the second determination unit 125 described above. The first determination unit 124 determines whether or not the ranges 31A and 31B indicating the two pieces of object information individually identified by the vehicle identification unit 123 have been integrated into one range 31C by subsequent identification processing. Once the position information of the center position of each of the ranges 31A and 31B is individually specified as the object information, as shown in the distribution curve W13 of FIG. is identified as object information, it is determined that the ranges 31A and 31B have been integrated into one range 31C.

It should be noted that the separation between the range 31A and the range 31B can be maintained by setting the set value of the predetermined threshold TH to a numerical value larger than the current value. However, as described above, in this embodiment where the distance resolution in the width direction D12 is low, if the threshold TH is increased, the detection accuracy of the position of the vehicle 30 indicated by the object information is lowered, which is not preferable.

When the first determination unit 124 determines that the ranges 31A and 31B have been integrated into one range 31C, the second determination unit 125 determines the detection area 45 indicated by the two pieces of object information before determination by the first determination unit 124. It is determined whether or not to maintain the separation state of the two object information based on the position within the vehicle, that is, the position of each of the two vehicles 30A and 30B. Such determination processing is performed based on the positions of the two pieces of object information in the running direction D11 and the positions in the width direction D12.

Specifically, the second determination unit 125 determines that the positions indicated by the two pieces of object information before determination by the first determination unit 124 are adjacent to the width direction D12, and that the two pieces of object information travel in the traveling direction. If the interval of D11 is gradually decreasing, it is determined that the separation state of the two pieces of object information is maintained. Here, the state of being adjacent in the width direction D12 includes not only the state in which each vehicle 30 is positioned right beside each lane 40A, 40B, but also the state in which each vehicle 30 is traveling in each lane 40A, 40B as viewed from the width direction D12. It also includes a state in which a part of each vehicle 30 is overlapped with the traveling direction D11. In this case, the vehicle 30B catches up with the vehicle 30A in the detection area 45, and the ranges 31A and 31B that were originally separated in the width direction D12 are integrated into one range 31C.

When the second determination unit 125 determines that the separated state of the two pieces of object information is to be maintained, the vehicle identification unit 123 divides the integrated range 31C into two in the width direction D12. A process of specifying object information is performed for each of the ranges 31C1 and 31C2. That is, the position information indicating the center position of the range 31C1 is specified as one object information, and the position information indicating the center position of the range 31C2 is specified as the other object information. An identification ID is assigned by the ID setting unit 126 to each of the two pieces of object information identified again.

[Vehicle information detection processing]
Hereinafter, the vehicle information detection direction, which is an example of the mobile object information detection method of the present invention, will be described together with the procedure of the vehicle information detection processing executed by the control unit 12, using the flowchart of FIG. In FIG. 7, S11, S12, . . . indicate processing procedure numbers (step numbers).

<Steps S11 to S13>
As shown in FIG. 7, in step S11, the control unit 12 determines whether or not the reflected wave signal SG2 from one scan of the radio signal SG1 has been received. Here, if it is determined that the reflected wave signal SG2 is received before the period T elapses, in the next step S12, the target measurement unit 122 of the control unit 12 selects a predetermined value from the plurality of reflected wave signals SG2. A target signal SG2 above the level is extracted. After that, in step S13, the vehicle identification unit 123 of the control unit 12 performs a process of identifying object information indicating one vehicle 30 from the plurality of target signals SG2 extracted in step S12. Here, step S13 is an example of the moving body identification step of the present invention.

<Steps S14 to S15>
In the next step S<b>14 , the control unit 12 determines whether or not the vehicle 30 exists in each of the lanes 40</b>A and 40</b>B of the detection area 45 . Such determination is made based on the position indicated by the object information identified in step S13.

<Steps S15 to S17>
When it is determined in step S14 that the vehicle 30 exists in each of the lanes 40A and 40B, in the next step S15, the ID setting unit 126 of the control unit 12 sets the object information corresponding to each vehicle 30. identification ID is assigned. After that, the position information indicated by the object information is specified as the measured position of the vehicle 30, and the measured position is stored in the storage unit 13 (S16). The control unit 12 also calculates the distance DS between the vehicles from the measured positions of the vehicles 30, and stores it in the storage unit 13 (S17).

<Steps S18 to S19>
In step S18, the control unit 12 determines whether or not the distance DS is less than a predetermined threshold. This determination is made to determine whether or not there is a high possibility that the two pieces of individually specified object information will be integrated into one when the process of step S13 is performed next. For example, the length corresponding to the total length of the vehicle 30 for the distance DS can be set as the threshold. If the distance DS is equal to or longer than the total length, the integration described above is unlikely to occur. Therefore, when it is determined in step S18 that the distance DS is equal to or greater than the threshold value, there is no need to execute the processing of step S25, which will be described later. In this case, the process proceeds to step S20 without giving each vehicle 30 flag information as a trigger for performing the process of step S25. On the other hand, when the distance DS is less than the threshold, it can be evaluated that each vehicle 30 is adjacent in the width direction D12, and the two pieces of object information are integrated into one in the processing of step S13 that is performed next. become. Therefore, when it is determined in step S18 that the distance DS is less than the threshold value, the control unit 12 adds flag information as a trigger for performing the process of step S25 to the object information corresponding to each vehicle 30 ( S19), and then the process proceeds to step S20.

<Steps S20 to S22>
In step S20, the control unit 12 determines whether the vehicle 30 exists within the counting area 46 based on the position indicated by the object information. If the vehicle 30 exists within the counting area 46, the identification ID associated with the object information is detected and the number of vehicles 30 is counted (S21). That is, the vehicle count value in the storage unit 13 is incremented by one. After that, the object information corresponding to the counted vehicle 30 and the flag information attached thereto are deleted from the storage part 13, and the flag information attached to the object information of the other vehicle 30 is also deleted (S22). On the other hand, when it is determined in step S20 that the vehicle 30 does not exist within the counting area 46, the process returns to step S11, and the processes after step S11 are repeated.

<Step S23>
If it is determined in step S14 that the vehicle 30 does not exist in each of the lanes 40A and 40B, that is, if it is determined that the vehicle 30 exists in only one of the lanes, the controller 12 performs the following step S23. , determines whether or not flag information is added to the object information corresponding to the vehicle 30 . This determination is made to determine whether or not the two pieces of object information individually identified in step S13 have been integrated. Step S23 is an example of the first determination step of the present invention. Here, the following two cases are conceivable as cases in which the state in which the vehicle 30 exists in each of the lanes 40A and 40B changes to the state in which the vehicle 30 exists in only one lane. One is a case where the vehicle 30 has passed through the counting area 46 and left the detection area 45 . The other is that since the vehicles 30 are running side by side at positions adjacent to each other in the width direction D12, the ranges 31A and 31B serving as the reference of each object information corresponding to the two vehicles 30 are integrated into one range 30C. This is the case where the object information is identified as one object information.

In the former case, the flag information is deleted in step S22. Therefore, in this case, it is determined in step S23 that the flag information is not given, the process proceeds to step S15, and the processes after step S15 are performed. In this case, the vehicle 30 is in only one of the lanes 40A and 40B, so the process of step S17 is skipped without being performed. In the latter case, the flag information attached to the vehicle 30 remains. In this case, it is determined that the flag information is attached in step S23, and the process proceeds to the next step S24.

<Steps S24 to S26>
In step S24, the control unit 12 determines whether or not the distance DS between the two vehicles 30 before integration has gradually decreased. Such determination is made to determine whether or not to maintain the separation state of the two pieces of object information before integration. Step S24 is an example of the second determination step of the present invention. The determination processing is performed based on the history of the distance DS stored in the storage unit 13 .

Here, the fact that the distance DS between the two vehicles 30 before integration gradually decreased means that the two vehicles 30 are relatively approaching, and it is estimated that the two vehicles 30 are likely to be integrated afterward. can. Therefore, if it is determined in step S24 that the distance DS between the two vehicles 30 before integration has gradually decreased, it is necessary to maintain the separated state of the two pieces of object information before integration. Therefore, the vehicle identification unit 123 of the control unit 12 divides the range 31C corresponding to the integrated object information into two in the width direction D12, and identifies the object information for each of the divided ranges 31C1 and 31C2. (S25). After that, an identification ID is assigned to each piece of object information (S26). Subsequent processing proceeds to step S21. On the other hand, when it is determined in step S24 that the distance DS between the two vehicles 30 before integration has not gradually decreased, the process proceeds to step S15, and the processes after step S15 are performed.

As described above, in the vehicle information detection device 10 according to the present embodiment, the radio signal SG1 is periodically transmitted toward the detection area 45 defined on the road surface 40, and the vehicle identification unit 123 detects the reflection of the radio signal SG1. The distribution of the wave signal SG2 is analyzed for each period, and a group whose distribution density is equal to or greater than a predetermined threshold value TH is identified as object information indicating one vehicle 30. It is determined whether or not the two ranges 31A and 31B corresponding to each of the two pieces of object information have been integrated into one. Based on the positions in the traveling direction D11 and the width direction D12 of the two vehicles 30 indicated by the two pieces of object information before the determination by the first determination unit 124, the second determination unit 125 determines the separation state of the two pieces of object information. is maintained. Then, when it is determined to maintain the separated state, the vehicle identification unit 123 divides the integrated range 31C into two in the width direction D12, and performs processing to identify object information for each of the ranges 31C1 and 31C2.

Therefore, even if the distance resolution in the width direction D12 is low, the detection area 45 does not have a hardware configuration using a high-performance IC or a unique algorithm for performing complicated arithmetic processing. can be counted. In other words, when the vehicles 30 of the respective lanes 40A and 40B are individually specified, even if the vehicles 30 run side by side at the same speed thereafter, they are not recognized as one vehicle, and the vehicles 30 are separated. state can be preserved. As a result, the number of vehicles 30 can be accurately counted. Further, when one vehicle 30A is a large vehicle such as a trailer or a bus, and the other vehicle 30B is a compact vehicle or a standard-sized vehicle, once each vehicle 30 is individually identified, the vehicle 30B is then identified as a vehicle. Even if each vehicle 30 passes through the counting area 46 after catching up with 30A and before overtaking, the separation state of each vehicle 30 is maintained. Therefore, even in such a case, the number of vehicles 30 can be accurately counted.

In the above-described embodiment, the control unit 12 of the vehicle information detection device 10 exemplifies the configuration in which the target measurement unit 122 and the vehicle identification unit 123 are specifically realized, but the present invention is not limited to this configuration. For example, an arithmetic processing unit may be provided inside the radar sensor 20, and each processing unit of the target measurement unit 122 and the vehicle identification unit 123 may be implemented by this arithmetic processing unit.

10: Vehicle information detection device 12: Control unit 13: Storage unit 14: Communication unit 15: Management server 20: Radar sensor 21: Antenna 22: Transmission circuit 23: Reception circuit 24: Oscillation circuit 25: Column 30: Vehicle 30A: Vehicle 30B: vehicle 30C: range 31A: range 31B: range 31C: range 31C1: range 31C2: range 40: road 40A: lane 40B: lane 45: detection area 46: counting area 100: vehicle information detection system 121: transmission control unit 122 : Target measurement unit 123 : Vehicle identification unit 124 : First determination unit 125 : Second determination unit 126 : ID setting unit 127 : Tracking processing unit 128 : Vehicle counting unit

Claims (8)

A moving object information detection device for detecting information on a plurality of moving objects moving in the same direction in a predetermined detection area,
Analyzing the distribution of reflected waves of radio waves periodically transmitted from the downstream side of the movement direction of the moving object toward the detection area for each period, and moving one group having a distribution density equal to or greater than a predetermined threshold value. a moving body identifying unit for identifying moving body information indicating a body;
When two pieces of moving object information are individually specified by the moving object specifying unit, the distribution density of the reflected wave in an intermediate region located between the two moving objects indicated by each piece of moving object information is the predetermined value. a first determination unit that determines whether or not the two groups corresponding to the two pieces of moving body information have been integrated into one group by determining whether or not the threshold is equal to or greater than the threshold;
When the first determining unit determines that the two groups have been integrated into one group , the progress of each of the two moving objects indicated by the two moving object information before determination by the first determining unit a moving object information detection device comprising: a second determination unit that determines whether or not to maintain the separation state of the two pieces of moving object information based on a direction and a position in a width direction that intersects with the traveling direction. The second determination unit
The two mobile bodies indicated by the two mobile body information before determination by the first determination unit are adjacent in the width direction, and the interval in the traveling direction of the two mobile bodies is gradually decreasing. 2. The moving body information detection device according to claim 1, wherein the mobile body information detecting device determines to maintain the separation state of the two moving body information when the mobile body information is present. The moving object identification unit
When it is determined by the second determination unit that the separation state of the two moving body information is to be maintained, the one group is divided into two in the width direction, and the moving body corresponding to each of the divided groups is determined. 3. The moving object information detection device according to claim 1, which specifies information. 4. The movement according to any one of claims 1 to 3, further comprising a counting unit that counts the number of said moving body information in a counting area defined downstream in said traveling direction in said detection area as the number of said moving bodies. Body information detector. further comprising an identification setting unit that sets an identification code to the mobile information identified by the mobile identification unit;
5. The moving object information detecting device according to claim 4, wherein said counting unit detects said identification code of said moving object information in said counting area, and counts the number of detection of said identification code as the number of said moving objects. 6. The moving object information detection apparatus according to claim 1, further comprising an output unit that outputs said moving object information specified by said moving object specifying unit. A moving object information detection method for detecting information on a plurality of moving objects moving in the same direction in a predetermined detection area,
Analyzing the distribution of reflected waves of radio waves periodically transmitted from the downstream side of the movement direction of the moving object toward the detection area for each period, and moving one group having a distribution density equal to or greater than a predetermined threshold value. a moving body identifying step of identifying the moving body information indicating the body;
When two pieces of moving object information are individually specified by the moving object specifying step, the distribution density of the reflected wave in an intermediate region located between the two moving objects indicated by each piece of moving object information is the predetermined value. a first determination step of determining whether or not the two groups corresponding to the two pieces of moving body information have been integrated into one group by determining whether or not the threshold of
when it is determined by the first determination step that the two groups have been integrated into one group , the progress of each of the two mobile bodies indicated by the two mobile body information before the determination by the first determination step; and a second determination step of determining whether or not to maintain the separation state of the two pieces of mobile information based on the direction and the position in the width direction intersecting the traveling direction. A program for causing a computer to execute each step of the moving body information detection method according to claim 7.

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