WO2021241501A1 - Radio wave sensor, object detection method, and setting method - Google Patents

Abstract

A radio wave sensor according to the present disclosure comprises: a transmitter that transmits radio waves; a receiver that receives reflected waves due to reflection of the radio waves from an object; a storage device that stores effective range data indicating an effective range which is set in a detection area for the radio wave sensor and in which the object is to be detected; and a processing device configured to perform an estimation process for estimating a direction of arrival of the reflected waves on the basis of reception data generated on the basis of the reflected waves. The reception data is obtained through reception by the receiver of the reflected waves from within the effective range and the reflected waves from a non-effective range which corresponds to the detection area excluding the effective range and in which the object is not to be detected. The processing device only performs the estimation process in the effective range indicated by the effective range data.

Description

Radio wave sensor, object detection method and setting method

The present disclosure relates to radio wave sensors, object detection methods and setting methods.
This application claims priority based on Japanese Application No. 2020-93071 filed on May 28, 2020, and incorporates all the contents described in the Japanese application.

Patent Document 1 discloses a radio wave sensor installed on a road. Patent Document 2 discloses that by measuring the direction of a reference object installed in a target area set to include a pedestrian crossing, it is possible to recognize a deviation in the direction of a radio wave sensor installed on a road. ..

Patent Document 3 discloses a radar device mounted on a vehicle.

Japanese Unexamined Patent Publication No. 2017-90138 Japanese Unexamined Patent Publication No. 2018-162977 Japanese Unexamined Patent Publication No. 2008-275460

One aspect of this disclosure is the radio wave sensor. The radio wave sensor of the present disclosure includes a transmitter that transmits radio waves, a receiver that receives reflected waves from which the radio waves are reflected from an object, and an effective detection target set in the detection area of the radio wave sensor. It includes a storage device that stores effective range data indicating a range, and a processing device configured to perform estimation processing of the arrival direction of the reflected wave based on the received data generated based on the reflected wave. The received data includes the reflected wave from the effective range and the reflected wave from the invalid range in which the effective range is excluded from the detection area and the object is not a detection target. It is the data obtained by receiving the receiver, and the processing apparatus executes the estimation process only in the effective range indicated by the effective range data.

Another aspect of the present disclosure is an object detection method using a radio wave sensor including a transmitter for transmitting radio waves and a receiver for receiving reflected waves from which the radio waves are reflected from an object. The method of the present disclosure stores the effective range data indicating the effective range for which the object is to be detected, which is set in the detection area of the radio wave sensor, and is based on the received data generated based on the reflected wave. The received data includes the reflected wave from within the effective range and the range obtained by removing the effective range from the detection area. The data is obtained by the receiver receiving the reflected wave from an invalid range in which the object is not a detection target, and the estimation process is executed only in the effective range indicated by the effective range data. NS.

Another aspect of the present disclosure sets an effective range in which the object is to be detected in a detection area of a radio wave sensor including a transmitter for transmitting radio waves and a receiver for receiving reflected waves from which the radio waves are reflected from an object. This is the setting method. The method of the present disclosure is to display information indicating the intensity distribution of the reflected intensity value of the reflected wave, to specify the position of the object existing in the detection area based on the information indicating the intensity distribution, and the above-mentioned. Determining whether or not the object existing at a position in the real space corresponding to the position is the detection target of the radio wave sensor, and setting an effective range in which the object is the detection target based on the result of the determination. A setting method that includes.

FIG. 1 is a schematic configuration diagram of a radio wave sensor. FIG. 2 is a schematic view showing an example of the detection area. FIG. 3 is a flowchart of the effective range setting process. FIG. 4 is a schematic diagram showing the relationship between the detection area and the effective range. FIG. 5 is a schematic diagram showing another example of the detection area. FIG. 6 is a schematic diagram showing another example of the detection area. FIG. 7 is a data structure diagram of effective range data. FIG. 8 shows the reflection intensity distribution in the distance zone. FIG. 9 shows the reflection intensity distribution in the distance zone. FIG. 10 is a schematic view of an angle band. FIG. 11 is a data structure diagram of effective range data. FIG. 12 is a flowchart of the object detection process. FIG. 13 is a data structure diagram of the reflection intensity data.

Patent Document 1 discloses a radio wave sensor installed on a road. The radio wave sensor of Patent Document 1 radiates radio waves to a target area set to include a pedestrian crossing and detects an object. Patent Document 2 discloses that by measuring the direction of a reference object installed in a target area set to include a pedestrian crossing, it is possible to recognize a deviation in the direction of a radio wave sensor installed on a road. ..

Patent Document 3 discloses a radar device mounted on a vehicle. The radar device of Patent Document 3 discloses that the detection angle range of a target object is changed depending on the distance from the vehicle. The radar device of Patent Document 3 widens the detection angle range in the case of a short distance and narrows the detection angle range in the case of a long distance.

[Problems to be solved by this disclosure]

In the case of a radio wave sensor installed as an infrastructure on a road or the like, a detection area, which is an area monitored by the radio wave sensor to detect an object, may be set. In Patent Document 1 and Patent Document 2, the detection area is described as a target area.

In the case of a radio wave sensor that monitors a set detection area, as in Patent Document 3, if the angle range is simply different depending on the distance, unnecessary arithmetic processing may occur in the radio wave sensor depending on the shape of the detection area. There is. For example, as in the radar device of Patent Document 3, even if the angle range is set wide in the case of a short distance and the angle range is set narrow in the case of a long distance, the shape of the detection area or the installation of the radio wave sensor Depending on the location, the detection area may not be covered properly. Depending on the shape of the detection area or the installation location of the radio wave sensor, the angle range may need to be set narrower in the case of a short distance. In addition, an area that does not require object detection may be set in the detection area. Even in such a case, if the angle range is simply different depending on the distance, useless calculation occurs.

As described above, since the shape of the detection area and the installation location of the radio wave sensor are various, if the angle range is simply different depending on the distance, the radio wave sensor may generate unnecessary arithmetic processing.

Therefore, it is desirable to suppress unnecessary arithmetic processing.

[Effect of this disclosure]

According to the present disclosure, unnecessary arithmetic processing can be suppressed.

[Explanation of Embodiments of the present disclosure]

(1) The radio wave sensor according to the embodiment is detected by a transmitter that transmits radio waves, a receiver that receives reflected waves from which the radio waves are reflected from an object, and the object set in the detection area of the radio wave sensor. A storage device that stores effective range data indicating a target effective range, and a processing device configured to execute estimation processing of the arrival direction of the reflected wave based on received data generated based on the reflected wave. The received data includes the reflected wave from the effective range and the reflection from the invalid range in which the effective range is excluded from the detection area and the object is not the detection target. It is data obtained by receiving a wave by the receiver, and the processing apparatus executes the estimation process only in the effective range indicated by the effective range data. Since the estimation process is executed only within the effective range, unnecessary arithmetic processing can be suppressed.

(2) The processing device may be configured to further execute the effective range setting process for generating the effective range data based on the detection area data indicating the detection area. In this case, the processing device can set the effective range. The radio wave sensor may acquire and store the effective range data set externally.

(3) The effective range data includes a value of a distance band which is a distance range in the radial direction of a polar coordinate system with the radio wave sensor as an origin, and a value of an angle range in the circumferential direction of the polar coordinate system. May be good. In this case, the effective range is set in the polar coordinate system.

(4) The storage device may store reflection intensity data indicating the reflection intensity value of the reflected wave. The value in the angle range may be greater than or equal to the reference value determined based on the intensity distribution of the reflection intensity value. In this case, it is possible to prevent the effective range from becoming too small.

(5) The reflection intensity data may be configured to be able to store the reflection intensity data in a preset maximum range. The effective range is a part of the maximum range, and the reflection intensity data has a first range corresponding to the effective range and a second range corresponding to the invalid range. May be good. The reflection intensity value of the reflected wave may be stored in the first range, and a value indicating that the estimation process has not been performed may be stored in the second range. In this case, it is possible to discriminate the portion of the reflection intensity data where the estimation process has not been performed.

(6) The radio wave sensor may be set with an angle band which is the resolution of the radio wave sensor in the circumferential direction of the polar coordinate system. The processing device may be configured to estimate the arrival direction for each of a plurality of the angle bands set within the effective range in the estimation process. The plurality of angle bands may include a first angle band and a second angle band having an angle range different from that of the first angle band. In this case, the arrival direction can be estimated for each different angle band.

(7) The plurality of distance bands may include a first distance band having the first angle band and a second distance band having the second angle band. In this case, the first distance band and the second distance band can each have different angle bands.

(8) The distance from the radio wave sensor in the second distance band is longer than the distance from the radio wave sensor in the first distance band, and the angle range of the second angle band is the angle range of the first angle band. It may be smaller. In this case, the farther from the radio wave sensor, the higher the resolution of the radio wave sensor.

(9) The estimation process calculates the reflected intensity value of the reflected wave with the incident angle of the reflected wave on the radio wave sensor as a variable based on the received data, and is based on the peak of the intensity distribution of the reflected intensity value. The process may be a process of determining the arrival direction of the reflected wave. The processing device may calculate the reflection intensity value by limiting it to the effective range indicated by the effective range data. In this case, since the calculation of the reflection intensity value is limited to the effective range data, the calculation load can be suppressed.

(10) The object detection method by the radio wave sensor according to the embodiment is based on storing the effective range data indicating the effective range in which the object is to be detected, which is set in the detection area of the radio wave sensor, and the reflected wave. It is provided to execute the estimation process of the arrival direction of the reflected wave based on the received data generated in the above. The received data receives the reflected wave from the effective range and the reflected wave from the invalid range in which the effective range is excluded from the detection area and the object is not the detection target. It is the data obtained by receiving the device. The estimation process is executed only in the effective range indicated by the effective range data. The computer program according to the embodiment causes the processing apparatus to execute the above-mentioned processing. Computer programs are stored on computer-readable, non-temporary storage media.

(11) The setting method using the radio wave sensor according to the embodiment is to display information indicating the intensity distribution of the reflected intensity value of the reflected wave, and based on the information indicating the intensity distribution, the object existing in the detection area. The object is to be detected based on the result of the determination, the determination of whether or not the object existing in the position in the real space corresponding to the position is the detection target of the radio wave sensor, and the result of the determination. It is provided to set the effective range. The computer program according to the embodiment causes the processing apparatus to execute the above-mentioned processing. Computer programs are stored on computer-readable, non-temporary storage media.

[Details of Embodiments of the present disclosure]

FIG. 1 shows a radio wave sensor 10 according to an embodiment. The radio wave sensor 10 according to the embodiment is used, for example, for monitoring a vehicle on a road or monitoring a pedestrian on a sidewalk or a pedestrian crossing. The radio wave sensor 10 is installed, for example, as road equipment which is an infrastructure. The radio wave sensor 10 according to the embodiment is also referred to as an infrastructure radio wave sensor or an infrastructure radar. Unlike the radio wave sensor mounted on the vehicle, the radio wave sensor 10 according to the embodiment is installed in a state of being fixed to the infrastructure near the detection area, which is the area where the radio wave sensor 10 detects an object.

The radio wave sensor 10 according to the embodiment is installed to monitor an object in the detection area T1 exemplified in FIG. The detection area T1 is a monitoring area by the radio wave sensor 10. In FIG. 2, the detection area T1 is installed as a range including the pedestrian crossing 200. In this case, the radio wave sensor 10 detects an object such as a pedestrian moving in the detection area T1.

The detection area T1 may be installed as a range including the road on which the vehicle travels. In this case, the radio wave sensor 10 detects an object such as a vehicle moving in the detection area T1.

The radio wave sensor 10 according to the embodiment detects an object by the reflection of the irradiated radio wave. The radio wave sensor 10 of the embodiment is configured as a millimeter wave radar sensor. As shown in FIG. 1, the radio wave sensor 10 includes a transmitter 11 that transmits a radio wave for detecting an object, a receiver 13 that receives a reflected wave of the transmitted radio wave, a signal processing device 15, and a processing device 110. , A storage device 120, and a communication interface 130. The receiver 13 outputs the received signal of the reflected wave to the signal processing device 15. The radio wave sensor 10 obtains the distance from the radio wave sensor 10 to the object and the existence angle of the object. The two-dimensional position coordinates of the object are specified from the distance and the angle. The transmitter 11 and the receiver 13 may be separate devices or may be one device.

The radio wave sensor 10 includes a signal processing device 15. The signal processing device 15 outputs the received data obtained by processing the received signal of the reflected wave to the processing device 110. The processing device 110 is, for example, a CPU (Central Processing Unit).

The processing device 110 according to the embodiment executes the effective range setting process 111. Further, the processing device 110 according to the embodiment executes the object detection processing 113. The effective range setting process 111 and the object detection process 113 will be described later.

The radio wave sensor 10 includes a storage device 120 connected to the processing device 110. The storage device 120 includes, for example, a primary storage device and a secondary storage device. The primary storage device is, for example, a RAM (Random access memory). The secondary storage device is, for example, a hard disk drive (HDD) or a solid state drive (SSD).

The storage device 120 stores the detection area data 121 and the effective range data 123. Further, the storage device 120 stores the reflection intensity data 125. The detection area data 121, the effective range data 123, and the reflection intensity data 125 will be described later.

The computer program 150 is stored in the storage device 120. The computer program 150 causes the processing device 110 to execute the effective range setting process 111. The computer program 150 includes a program code for causing the processing device 110 to execute the effective range setting process 111. Further, the computer program 150 causes the processing device 110 to execute the object detection process 113. The computer program 150 includes a program code for causing the processing device 110 to execute the object detection process 113. The processing device 110 reads out and executes the computer program 150 stored in the storage device 120.

The radio wave sensor 10 includes a communication interface 130 for communicating with an external device. The communication interface 130 is an interface for wireless communication or wired communication. The radio wave sensor 10 can transmit and receive data to and from an external device via the communication interface 130. The external device may be, for example, a server on a network, a roadside sensor other than another radio wave sensor or a radio wave sensor, or a device connected to the radio wave sensor 10.

A detection area setting device 20 is connected to the communication interface 130 as an external device. The detection area setting device 20 is a computer in which a computer program for setting the detection area T1 is stored. Setting the detection area T1 The worker sets the detection area T1 by using the detection area setting device 20. The detection area T1 is set to a size and shape including the pedestrian crossing 200 and its vicinity, for example, according to the size and shape of the pedestrian crossing 200 which is a monitoring area.

The detection area setting device 20 generates the detection area data 121 indicating the detection area T1 in response to the operation of the determination area setting by the setting worker. The detection area data 121 indicates the size and shape of the detection area T1. The detection area data 121 includes, for example, coordinate data for defining the shape of the detection area data 121 with the position of the radio wave sensor 10 installed in the vicinity of the detection area T1 as a reference position. Since the size and shape of the pedestrian crossing or the road serving as the monitoring area are various, the size and shape of the detection area T1 are also various. By the setting work of the detection area T1, an appropriate detection area T1 corresponding to various monitoring areas is set.

The processing device 110 of the radio wave sensor 10 can obtain two-dimensional position coordinates indicating where an object exists in the detection area T1. As a result, it is possible to obtain the movement locus of a pedestrian or the like in the detection area T1.

When the detection area setting device 20 generates the detection area data 121, the detection area data 121 is output to the radio wave sensor 10. When the radio wave sensor 10 receives the detection area data 121 via the communication interface 130, the radio wave sensor 10 stores the detection area data 121 in the storage device 120. The stored detection area data 121 is used to generate the effective range data 123 by the processing device 110 of the radio wave sensor 10.

FIG. 3 shows the procedure of the effective range setting process 111 executed by the processing device 110. In the embodiment, the effective range has an effective range in the angular direction and an effective range in the distance direction as seen from the radio wave sensor 10. Here, the angular direction refers to the circumferential direction of the polar coordinate system with the radio wave sensor 10 as the origin, and the distance direction refers to the radial direction (radial direction) of the polar coordinate system with the radio wave sensor 10 as the origin. In step S11, the processing device 110 reads the detection area data 121 from the storage device 120. In step S12, the processing device 110 sets a second detection area T2 having a predetermined width margin around the detection area T1 (first detection area) indicated by the detection area data 121. FIG. 4 shows a first detection area T1 and a second detection area T2 (a detection area T2 with a margin). The margin around the first detection area T1 may not be secured, but if the margin is secured, an object outside the first detection area T1 but within the margin can be detected, which is advantageous.

In step S13, the processing device 110 sets the effective angle range C required to cover the second detection area T2 for each of the plurality of distance bands D. The distance band D is a distance range in the radial direction of the polar coordinate system with the radio wave sensor 10 as the origin. For example, a distance A of 10 m in the radial direction from the radio wave sensor 10, a distance B of 20 m in the radial direction from the radio wave sensor 10, a distance C of 30 m in the radial direction from the radio wave sensor 10, and a radio wave sensor 10 A distance of 40 m in the radial direction from the distance is defined as a distance D. In this case, the range between the distance A and the distance B is the distance zone D defined by the distance range of 10 m to 20 m in the radial direction, and the range between the distance B and the distance C is the radial direction. Is the distance zone D defined in the distance range of 20 m to 30 m in the above, and the range between the distance C and the distance D is the distance zone D defined in the distance range of 30 m to 40 m in the radial direction. The distance band D is set, for example, in units of 1 m, but the unit of the distance band D is not particularly limited. For example, when the second detection area T2 exists 20 m ahead of the radio wave sensor 10, 20 distance zones D in 1 m units are set. The effective angle range C set for each distance zone D may be the minimum necessary to cover the second detection area T2. Therefore, as shown in FIG. 4, the effective angle range C is different for each distance band D. Setting of the detection area T1 Since the operator can freely set the effective angle range C for each distance zone D according to the shape of the second detection area T2, the flexible effective angle range C can be set.

In FIG. 4, the effective angle range C becomes smaller as the distance band D farther from the radio wave sensor 10. However, the setting of the effective angle range C in FIG. 4 is an example, and is not limited to such a setting. For example, in the arrangement of the radio wave sensor 10 shown in FIG. 5, the second angle range G2 in a slightly distant distance zone is wider than the first angle range G1 in a distance zone relatively close to the radio wave sensor 10. Further, the second angle range G3 in a farther distance zone is narrower than the second angle range G2. As described above, the angle range may not be uniformly reduced even if the distance from the radio wave sensor 10 is increased. However, according to the present embodiment, the worker who sets the detection area T1 can set the effective angle range C for each distance zone D, so that even in the case of FIG. 5, the minimum necessary effective angle range C is set. Can be set.

Further, as shown in FIG. 6, when the utility pole 220 or the tree exists in the detection area T1, the non-detection area 230 may be set in the detection area T1. By setting the place where the utility pole 220 or the like exists as the non-detection area 230, the utility pole 220 or the like is not detected as an object to be detected such as a person. As a result, false positives are prevented. The non-detection area 230 in the detection area T1 may be a place where no one can enter. Objects excluded from detection targets include guardrails, medians, gutters, signboards, etc., in addition to utility poles and trees.

For example, if the utility pole 220 exists in a range of −10 ° to + 10 ° in a certain distance zone D, and the setting worker of the detection area T1 wants to set the range to the non-detection area 230, in the present embodiment, the installation worker , The effective angle range C of the distance zone D can be set, for example, from −40 ° to −10 ° and from + 10 ° to + 40 °. As described above, according to the present embodiment, since the effective angle range C can be set for each distance zone D, the effective angle range C can be set while avoiding the angle corresponding to the non-detection area 230 as shown in FIG. The installation worker determines whether or not the object detected by the radio wave sensor 10 is the detection target by referring to the image of the detection area captured by the image pickup device such as a camera or by visually observing the detection area. For example, if the installation worker finds out from an image or visual inspection that an object existing at a position in the real space corresponding to the position of the object detected by the radio wave sensor 10 is a tree or a utility pole, the installation worker must detect this object. Determine. The installation worker can set the non-detection area based on the determination result.

FIG. 7 shows an example of the effective range data 123 generated by the processing device 110 according to the setting in step S13. The valid range data 123 is configured to indicate a valid range and an invalid range within a preset maximum range. The effective range is a set of the plurality of effective angle ranges C described above. The effective range is the range in which the estimation process S24 in the arrival direction, which will be described later, is executed. The invalid range is a range in which the estimation process S24 in the arrival direction, which will be described later, is not executed. The effective range is set as a range corresponding to the detection area T1 within the maximum range by the process of step S13. The invalid range is a range other than the valid range within the maximum range.

In the embodiment, the maximum range is defined by the maximum distance from the radio wave sensor 10 and the maximum angle range M. The maximum distance is, for example, 100 m from the radio wave sensor 10. The maximum angle range M is, for example, −90 ° to 90 ° as shown in FIG.

The effective range data 123 shown in FIG. 7 shows the effective range and the invalid range for each distance band D. In FIG. 7, the effective range for each distance band D is shown as an effective angle range C1, C2, and C3. The effective range data 123 shown in FIG. 7 is, for example, the effective angle range C1 and the invalid range F in the distance band D 9 m from the radio wave sensor 10, the effective angle range C2 and the invalid range F in the distance band D of 10 m, and 11 m. The effective angle range C3 and the invalid range F in the distance zone D are shown.

In the effective range data 123, in each distance band D, the angle in the effective range is indicated by "1", and the angle in the invalid range is indicated by "0". The set of ranges indicated by "1" is the valid range, and the set of ranges indicated by "0" is the invalid range. In FIG. 7, different effective angle ranges C1, C2, and C3 are set for each distance band D. In the effective range data 123 shown in FIG. 7, the setting operator of the detection area T1 can set valid or invalid for each angle in each distance band D. Therefore, the worker who sets the detection area T1 can flexibly set the effective range corresponding to the detection area T1 having an arbitrary shape.

In step S14 of FIG. 3, the processing device 110 determines whether or not the effective angle range C of each distance band D set in step S13 is equal to or greater than the reference value. The distance zone D to be determined here is the distance zone D in which the effective angle range C exists. The distance zone D in which the effective angle range C does not exist at all is not the target of the determination.

If the effective angle range C is equal to or greater than the reference value (“YES” in step S14) in a certain distance zone D, the effective angle range C set in step S13 is maintained. If the effective angle range C is less than the reference value (“NO” in step S14) in a certain distance band D, the effective angle range C in the distance band D is set to the reference value (step S15). This prevents the setting of an effective angle range C that is too small.

The reference value indicates a range in the angular direction with respect to the radio wave sensor 10, and is set to a size required for the radio wave sensor 10 to detect an object. The graph of FIG. 8 shows the intensity distribution of the received radio wave in the specific distance band D. The horizontal axis of the graph shows the angle in the circumferential direction in the polar coordinate system with the radio wave sensor 10 as the origin, and the vertical axis of the graph shows the intensity of the radio wave received by the radio wave sensor 10. A straight line passing through 0 ° on the horizontal axis regardless of the distance from the radio wave sensor 10 forms the center of the fan-shaped area and both ends of the arc of the fan-shaped area when the shape of the area where the radio wave is emitted is fan-shaped. It coincides with the midpoint of the connecting line segment and the straight line connecting them. In the detection of an object by the radio wave sensor 10, as shown in FIG. 8, if the difference between the maximum point P and the minimum points V1 and V2 in the distribution of the reflected intensity of the reflected wave for each distance band D is equal to or larger than the threshold value, It is determined that the maximum point P is the peak point corresponding to the object. Therefore, in order to determine the existence of the peak point, it is necessary to calculate the minimum points V1 and V2 in the vicinity of the maximum point P. As shown in FIG. 8, if the effective angle range C is sufficiently wide, the maximum point P and the minimum points V1 and V2 exist within the effective range, so that the processing apparatus 110 obtains the maximum point P as the peak point. Is possible. The angle corresponding to the peak point is the angle of existence of the object. When the installation worker specifies the position of the object from the intensity distribution shown in FIG. 8, the installation worker confirms the object existing at the position in the real space corresponding to the position by the image of the camera or visually. Then, if the object is a utility pole or a tree, the installation worker determines that the object is not the detection target of the radio wave sensor 10.

On the other hand, as shown in FIG. 9, if the effective angle range C is too narrow, the minimum points V1 and V2 do not exist in the effective range, and the processing device 110 cannot obtain the maximum point P as the peak point. .. Therefore, the effective angle range C may have a size larger than a certain level so that the peak point can be detected. In the setting of step S13, the minimum necessary effective angle range C corresponding to the detection area T2 is set, so that the effective angle range C may be too small. However, in step S15, the effective angle range C is set to a width equal to or larger than the reference value in advance, so that the setting of the effective angle range C that is too narrow is prevented. Note that 0 ° in FIG. 9 is the center of the fan-shaped area and the fan-shaped area when the shape of the area where the radio wave is radiated is fan-shaped. Let 0 ° be the straight line connecting the midpoint of the line segment connecting both ends of the arc.

The reference value may be different for each distance band D, or may be a uniform value regardless of the distance band D. Further, the reference value does not have to be a preset value, and may be appropriately set according to the intensity distribution of the reflected wave, or may be changed during the operation of the radio wave sensor 10.

In step S16 of FIG. 3, the processing device 110 sets the sizes of the angle bands A1 and A2 for each distance band D. The processing device 110 of the embodiment performs the estimation processing S24 of the arrival direction of the reflected wave for each of the predetermined angle bands A1 and A2. As shown in FIG. 10, the angle bands A1 and A2 indicate an angle range in the angle direction with respect to the radio wave sensor 10.

In FIG. 10, in the first distance band D1, the first angle band A1 is set, and in the second distance band D2, which is farther from the radio wave sensor 10 than the first distance band D1, the second angle band A2 is set. It is set. In FIG. 10, the first angle band A1 and the second angle band A2 have different angle ranges, and more specifically, the first angle band A1 is narrower than the second angle band A2. The angle range of the first angle band A1 is, for example, 1 °, and the angle range of the second angle band A2 is, for example, 0.5 °. The size of the angle bands A1 and A2 defines the resolution of the reflection intensity distribution. Therefore, the angle bands A1 and A2 correspond to the resolution of the radio wave sensor 10 in the circumferential direction of the polar coordinate system with the radio wave sensor 10 as the origin. If the angle bands A1 and A2 are large, the resolution becomes coarse, and if the angle bands A1 and A2 are small, the resolution becomes fine.

In the first distance band D1 relatively close to the radio wave sensor 10, even if the effective angle range C is wide, the physical range corresponding to the effective angle range C is relatively narrow. Therefore, in the first distance band D1, even if the first angle band A1 is increased and the resolution becomes coarse, the physical range is originally narrow, so that sufficient resolution is ensured.

On the other hand, in the second distance band D2, which is relatively far from the radio wave sensor 10, even if the effective angle range C is narrow, the physical range corresponding to the effective angle range C is not narrow. Therefore, in the second distance band D2, sufficient resolution is ensured by making the second angle band A2 smaller and making the resolution finer.

FIG. 11 shows an example of effective range data 123 showing a plurality of angle bands A1 and A2 set within the effective range. In the effective range data 123 of FIG. 11, the angle unit in which the valid “1” or the invalid “0” can be set is 0.5 ° in each distance band. As shown in FIG. 10, in the first distance band D1 in which the first angle band A1 having an angle range of 1 ° is set, "1" indicating validity is set for each 1 ° and "1" indicating invalidity is set. "0" is set to −0.5 °, 0.5 °, 1.5 °, 2.5 °, etc. That is, in the first distance band D1, the first angle band A1 in units of 1 degree is set. Therefore, in the first distance band D1, the arrival direction is estimated every 1 °.

In the second distance band D2 where the second angle band A2 having an angle range of 0.5 ° is set, "1" indicating effectiveness is set every 0.5 °. That is, in the second distance band D2, the second angle band A2 in units of 0.5 ° is set. Therefore, in the second distance band D2, the arrival direction is estimated every 0.5 °.

The angle bands A1 and A2 may be set automatically by the processing device 110 according to the distance band, or may be manually set by the user when the processing device 110 accepts an operation by the user.

In step S17 of FIG. 2, the processing device 110 stores the effective range data 123 set as described above in the storage device 120. The stored effective range data 123 is referred to by the processing device 110 when estimating the arrival direction of the reflected wave.

FIG. 12 shows the procedure of the object detection process 113 executed by the radio wave sensor 10. In step S11, the transmitter 11 of the radio wave sensor 10 radiates a transmitted wave for detecting an object. In step S12, the receiver 13 of the radio wave sensor receives the reflected wave in which the emitted transmitted wave is reflected by the object. The received signal of the reflected wave received by the receiver 13 is given to the signal processing device 15. The signal processing device 15 feeds the received data to the processing device 110. The received data is, for example, digital data showing a reflected wave.

In step S23, the processing device 110 executes the distance profile calculation process. The distance to the object is calculated by the time required from the time when the transmitter 11 transmits the transmitted wave to the time when the receiver 13 receives the reflected wave. This required time is the time required for the radio wave to reciprocate between the radio wave sensor 10 and the object. Therefore, the processing device 110 can obtain the distance from the radio wave sensor 10 to the object from this required time. The processing device 110 calculates the distance profile by performing a fast Fourier transform (FFT) on the received data in the distance profile calculation process.

In step S24, the processing device 110 executes estimation processing of the arrival direction of the reflected wave based on the received data of the reflected wave. The arrival direction is calculated based on the phase difference of the reflected wave between the plurality of antenna elements of the receiver 13. The estimation process in the arrival direction is executed only within the effective range indicated by the effective range data 123, and is not executed outside the effective range, that is, in the invalid range F. Since the processing device 110 does not execute the estimation process in the invalid range F, the calculation load of the processing device 110 is reduced.

Here, a method of estimating the arrival direction of a general reflected wave will be explained. It is assumed that the radio wave sensor has a plurality of antennas, and each antenna receives the reflected wave from the object at the incident angle θ. Each antenna generates a received signal (received data) based on the received reflected wave, and the radio wave sensor takes the sum of the received signals generated by each antenna. In other words, the radio wave sensor generates a composite signal by synthesizing the received signals generated by each antenna. At this time, the radio wave sensor multiplies the received signal of each antenna by a weighting function and then sums the received signals. The weighting function is a function for making the received signals of each antenna in phase, and includes the incident angle θ as a variable. By aligning the received signals of each antenna in the same phase, the amplitude of the sum of the received signals is maximized. The combined signal, which is the sum of each received signal, is also a function that includes the incident angle θ as a variable. The radio wave sensor calculates the signal strength (radio wave strength) of the composite signal by multiplying the square of the absolute value of the amplitude of the composite signal by a coefficient. The signal strength of the combined signal is also a function that includes the incident angle θ as a variable. The radio wave sensor calculates the signal strength of the combined signal while changing the value of the incident angle θ within the maximum angle range. As a result, for example, a signal intensity distribution showing a change in the signal intensity of the combined signal according to the change in the angle (incident angle θ) shown in FIG. 8 can be obtained. The radio wave sensor estimates the angle corresponding to the peak of the signal intensity distribution as the arrival direction of the reflected wave. The radio wave sensor makes this estimation for each distance band. As described above, a method of manipulating the phase of the received signal of each antenna over a certain angle range and searching for a direction in which the value of the signal strength increases is generally used for the estimation process of the arrival direction. For example, the beamformer method, the Capon method, and the linear prediction method use the above method for the estimation process in the arrival direction. On the other hand, in the estimation process of the arrival direction of the present disclosure, the process of changing the incident angle θ to calculate the signal strength of the combined signal is limited to the angle (incident angle) included in the effective range. For example, if 0 ° to 90 ° is an effective range, the above calculation is performed in the range of 0 ° to 90 ° and not in the range of −90 ° to less than 0 °. This reduces the computational load. Hereinafter, the description of the object detection process of FIG. 24 will be returned to.

In order to execute the estimation process only within the effective range, the processing device 110 reads the effective range data 123 from the storage device 120 and grasps the effective range. The processing device 110 executes the estimation process only at the angle indicated by "1" in each distance band D in the effective range data 123. The processing device 110 does not execute the estimation process at the angle indicated by "0".

Since the reflected wave comes from outside the effective range, that is, from the invalid range, the received data also shows information about the reflected wave from outside the effective range. That is, the received data is data obtained by the radio wave sensor 10 receiving the reflected wave from within the effective range and outside the effective range. The processing device 110 according to the embodiment reduces the calculation load by omitting the estimation processing for the outside of the effective range while using the received data including the information outside the effective range.

In the arrival wave estimation process in step S24, the reflected intensity of the reflected wave is calculated in each of the set angle bands A1 and A2 for each distance band D indicated by the effective range data 123. That is, the processing device 110 calculates the reflected intensity of the reflected wave only at the angle indicated by "1" in each distance band D in the effective range data 123. The processing device 110 does not calculate the reflection intensity at the angle indicated by "0".

The calculated reflection intensity is stored in the reflection intensity data 125. FIG. 13 shows an example of the reflection intensity data 125. The reflection intensity data 125 is configured to store the reflection intensity at each position within a preset maximum range. The reflection intensity is the reception intensity of the reflected wave received by the receiver 120. The value of the reception intensity may be referred to as the reflection intensity value. The maximum range here is the same as the maximum range of the effective range data 123. That is, the maximum range is defined by the maximum distance from the radio wave sensor 10 and the maximum angle range M. The maximum distance is, for example, 100 m from the radio wave sensor 10. The maximum angle range M is, for example, −90 ° to 90 ° as shown in FIG. The effective range is a part of the maximum range. Since the reflection intensity data 125 can store the reflection intensity within the maximum range in which the radio wave sensor 10 can detect an object, it can correspond to an effective range of various sizes or shapes.

The reflection intensity data 125 shown in FIG. 13 is configured to be able to store the reflection intensity at each angle for each distance band D. The reflection intensity data 125 of FIG. 13 shows, as an example, the reflection intensity v at each angle in the first distance band D1 and the reflection intensity v at each angle in the second distance band D2.

Since the maximum range in the reflection intensity data 125 is wider than the effective range, the reflection intensity data 125 includes the first range R corresponding to the effective range (effective angle range C1 and C2 in each distance band D) and the outside of the effective range (the effective range R). It has a second range N corresponding to the invalid range).

As shown in FIG. 13, the reflection intensity v, which is the result of the executed estimation process, is stored in the first range R corresponding to the effective angle ranges C1 and C2. On the other hand, in the second range N corresponding to the outside of the effective range (invalid range F), a value indicating that the estimation process is not executed is stored. The value indicating that the estimation process has not been executed indicates, for example, a value that the reflection intensity v cannot take. The value that the reflection intensity v cannot take is, for example, a null value.

The reflection intensity data 125 has a region for storing the reflection intensity even outside the effective range of the estimation process. Therefore, when a value (for example, 0) that the reflection intensity can take is stored in the region where the estimation process is not executed, the processing device 110 estimates the reflection intensity in the region where the estimation process is not executed. There is a risk of misrecognition as the resulting value. On the other hand, in the second range N corresponding to the outside of the effective range (invalid range F), a value indicating that the estimation process is not executed is stored, so that the erroneous recognition is prevented.

The reflection intensity data 125 obtained by the estimation process in step S24 shows the reflection intensity spectrum for each of the plurality of distance bands D. The reflection intensity spectrum obtained in step S24 corresponds to the distribution within the effective angle range C among the intensity distributions shown in FIG. That is, in the estimation process of step S24, the intensity distribution in the invalid range F in FIG. 8 is not obtained.

In step S25, if the difference between the maximum point P and the minimum points V1 and V2 in the reflection intensity distribution within the effective angle range C is equal to or greater than the threshold value, the maximum point P is the peak point corresponding to the object. (See FIG. 8). The angle corresponding to the peak point is the angle of existence of the object. In step S26, the processing device 110 is based on the distance from the radio wave sensor 10 to the distance zone D where the peak point exists and the angle at which the peak point exists when the radio wave sensor 10 is the origin of the polar coordinate system. , Detects the position where the object exists. The processing device 110 obtains two-dimensional position coordinates indicating where the object exists in the detection area T1. As a result, it is possible to obtain the movement locus of a pedestrian or the like in the detection area T1.

Each process (each function) of the above-described embodiment can be realized by a process circuit. For example, each process of the present embodiment can be realized by a processor that operates based on information such as a program and a storage device (memory) that stores information such as a program. In the processor here, for example, the functions of each part may be realized by individual hardware, or the functions of each part may be realized by integrated hardware. For example, the processor includes hardware, which hardware can include at least one of a circuit that processes a digital signal and a circuit that processes an analog signal. For example, a processor can be composed of one or more circuit devices (eg, ICs, etc.) mounted on a circuit board, or one or more circuit elements (eg, resistors, capacitors, etc.). The processor may be, for example, a CPU. However, the processor is not limited to the CPU, and various processors such as GPU (Graphics Processing Unit) or DSP (Digital Signal Processor) can be used. Further, the processor may be a hardware circuit by ASIC. Further, the processor may be configured by a plurality of CPUs or may be configured by a hardware circuit by a plurality of ASICs. Further, the processor may be configured by a combination of a plurality of CPUs and a hardware circuit by a plurality of ASICs. Further, the processor may include an amplifier circuit, a filter circuit, and the like for processing an analog signal. The memory may be a semiconductor memory such as SRAM or DRAM, a register, a magnetic storage device such as a hard disk device, or an optical storage device such as an optical disk device. You may.

It should be considered that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is indicated by the scope of claims, not the above-mentioned meaning, and is intended to include the meaning equivalent to the scope of claims and all modifications within the scope.

10 radio wave sensor, 11 transmitter, 13 receiver, 15 signal processing device, 20 detection area setting device, 110 processing device, 111 effective range setting processing, 113 object detection processing, 120 storage device, 121 detection area data, 123 effective range Data, 125 reflection intensity data, 130 communication interface, 150 computer program, 200 crosswalk, 220 electric pole, 230 non-detection area, A1 first angle band, A2 second angle band, C effective angle range, C1 effective angle range, C2 Effective angle range, C3 effective angle range, D distance band, D1 first distance band, D2 second distance band, F invalid range, G1 first angle range, G2 second angle range, G3 second angle range, M maximum angle Range, N 2nd range, P maximum point, R 1st range, S24 estimation processing, T1 1st detection area, T2 2nd detection area, V1 minimum point, V2 minimum point, v reflection intensity

Claims (11)

1. It ’s a radio wave sensor.
   A transmitter that transmits radio waves and
   A receiver that receives the reflected wave reflected from the object by the radio wave, and
   A storage device set in the detection area of the radio wave sensor and storing effective range data indicating an effective range in which the object is to be detected, and a storage device.
   A processing device configured to perform estimation processing of the arrival direction of the reflected wave based on the received data generated based on the reflected wave, and
   Equipped with
   The received data receives the reflected wave from the effective range and the reflected wave from the invalid range in which the effective range is excluded from the detection area and the object is not the detection target. It is the data obtained by receiving the device,
   The processing device is a radio wave sensor that executes the estimation process only in the effective range indicated by the effective range data.
2. The radio wave sensor according to claim 1, wherein the processing device further executes an effective range setting process for generating the effective range data based on the detection area data indicating the detection area.
3. The effective range data is claimed 1 or 2 including a value of a distance band which is a distance range in the radial direction of a polar coordinate system with the radio wave sensor as an origin and a value of an angle range in the circumferential direction of the polar coordinate system. Radio sensor described in.
4. The storage device stores reflection intensity data indicating the reflection intensity value of the reflected wave.
   The value in the angle range is equal to or greater than the reference value determined based on the intensity distribution of the reflection intensity value.
   The radio wave sensor according to claim 3.
5. The reflection intensity data is configured to be able to store the reflection intensity data in a preset maximum range.
   The effective range is a part of the maximum range.
   The reflection intensity data has a first range corresponding to the effective range and a second range corresponding to the invalid range.
   Any one of claims 1 to 4, wherein the reflected intensity value of the reflected wave is stored in the first range, and a value indicating that the estimation process is not performed is stored in the second range. The radio wave sensor described in the section.
6. The radio wave sensor is set with an angle band which is the resolution of the radio wave sensor in the circumferential direction of the polar coordinate system.
   In the estimation process, the processing device estimates the arrival direction for each of the plurality of angle bands set in the effective range.
   The radio wave sensor according to any one of claims 1 to 5, wherein the plurality of angle bands include a first angle band and a second angle band having an angle range different from that of the first angle band.
7. The radio wave sensor according to claim 6, wherein the plurality of distance bands include a first distance band having the first angle band and a second distance band having the second angle band.
8. The distance from the radio wave sensor in the second distance band is longer than the distance from the radio wave sensor in the first distance band.
   The radio wave sensor according to claim 7, wherein the angle range of the second angle band is smaller than the angle range of the first angle band.
9. In the estimation process, the reflected intensity value of the reflected wave with the incident angle of the reflected wave on the radio wave sensor as a variable is calculated based on the received data, and the reflection is based on the peak of the intensity distribution of the reflected intensity value. It is a process that determines the direction of arrival of waves.
   The processing device calculates the reflection intensity value by limiting it to the effective range indicated by the effective range data.
   The radio wave sensor according to claim 1.
10. An object detection method using a radio wave sensor including a transmitter for transmitting radio waves and a receiver for receiving reflected waves from which the radio waves are reflected from an object.
    To store effective range data indicating the effective range for which the object is to be detected, which is set in the detection area of the radio wave sensor.
    Performing estimation processing of the arrival direction of the reflected wave based on the received data generated based on the reflected wave,
    Equipped with
    The received data receives the reflected wave from the effective range and the reflected wave from the invalid range in which the effective range is excluded from the detection area and the object is not the detection target. It is the data obtained by receiving the device,
    The estimation process is an object detection method executed only in the effective range indicated by the effective range data.
11. A setting method for setting an effective range in which an object is to be detected in a detection area of a radio wave sensor including a transmitter for transmitting radio waves and a receiver for receiving reflected waves from which the radio waves are reflected from an object.
    Displaying information indicating the intensity distribution of the reflected intensity value of the reflected wave,
    To identify the position of the object existing in the detection area based on the information indicating the intensity distribution.
    Determining whether or not the object existing in the position in the real space corresponding to the position is the detection target of the radio wave sensor.
    To set the effective range for the object to be detected based on the result of the determination.
    Setting method to provide.

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