JP2001091653A - Method for detecting object, and method of and device for detecting obstacle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an object inside a certain area in a shorter time. SOLUTION: An object inside a certain area is detected by rotating a casing 21 within a predetermined angle range, concurrently transmitting radio waves from a long range antenna 11a, an intermediate range antenna 11b, and a short range antenna 11c, and receiving each reflected wave (S11). A processor 13 merges each detection data obtained from the long range antenna 11a, the intermediate range antenna 11b, and the short range antenna 11c and obtains detection data of the object inside the certain area (S13). Furthermore, an obstacle is extracted from this detection data (S14).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for detecting an object,
The present invention relates to an obstacle detection method and an obstacle detection device.

[0002]

2. Description of the Related Art There has been proposed a detection system which emits a radio wave from an antenna and receives a reflected wave of the radio wave by the antenna to detect an object within a certain range.

On an expressway or the like, if an obstacle exists on the road, it becomes extremely dangerous for the vehicle to travel. Therefore, the presence or absence of an obstacle on the road is detected, and if an obstacle exists, the vehicle is driven. It is useful to improve safety if it can be notified to the person.

[0004]

However, conventionally,
There is no system that detects obstacles on the road and informs the driver of their presence.

In order to construct a system for detecting an obstacle on a road, it is necessary to detect an object within a certain range from a short distance to a certain distance. In order to increase the detection distance of the antenna, it is necessary to narrow the beam width of the radio wave radiated from the antenna. On the other hand, in order to scan a near distance from the antenna, it is necessary to scan over a wider angle range than a far distance. Therefore, if one antenna is used for scanning from a long distance to a short distance, it is necessary to scan the antenna over a wide angle range, and it takes a long time to detect an object by the scanning time.

An object of the present invention is to enable an object within a certain range to be detected in a shorter time.

[0007]

According to the first aspect of the present invention,
Radio waves are radiated from a plurality of antennas having different detection distances, reflected waves of the radio waves are received by the plurality of antennas, respectively, and objects within a certain range are detected based on the respective reflected waves received by the plurality of antennas. .

According to the present invention, for example, by making the radiation angle range of the radio wave of the antenna having a shorter detection distance wider than the radiation angle range of the radio wave of the antenna having a longer detection distance, a predetermined range close to the antenna is scanned. In this case, the scanning angle range can be narrowed. As a result, the scanning time of the antenna can be reduced, so that an object within a certain range can be detected in a shorter time.

For example, a plurality of antennas are constituted by at least two antennas, a short-range antenna for detecting an object at a short distance from the antenna and a long-distance antenna for detecting an object at a longer distance from the antenna. By making the radiation angle range of the radio wave of the antenna wider than the radiation angle range of the radio wave of the long distance antenna, the scanning angle range of the short distance antenna for scanning a certain range can be narrowed.

Means for changing the radiation direction of the radio wave of the antenna can be realized, for example, by mounting a plurality of antennas having different detection distances on the same housing and rotating the housing over a predetermined angle range.

[0011] Thus, a plurality of antennas can be rotated by one drive system in a manner similar to the case where one antenna is used.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram of a road obstacle detection system according to an embodiment of the present invention.

This obstacle detection system includes an antenna 11 installed along a road and a display panel 12 installed at a position beside or across the road so that the driver can see it.
And a processing device (comprising a personal computer or the like) 1
3 and an integrated center 14 for monitoring obstacles on the road on the basis of obstacle detection data transmitted from the obstacle detection devices.

The antenna 11 transmits and receives radio waves in the millimeter wave band, and includes three types of antennas having different detection distances as described later. The antenna 11 is installed along the road, radiates radio waves to a certain area on the road, receives the reflected waves, and detects objects on and around the road.

As shown in FIG. 2A, the antenna 11 includes three types of antennas 11a to 11c having different diameters, each of which is vertically arranged two times. Antenna 11a
Is a long-distance antenna having a diameter of 12 inches and detecting an object at a position of about 180 m to 120 m away. The antenna 11b is a medium-distance antenna having a diameter of 6 inches and detecting an object at a position about 120 m to 80 m away. The antenna 11c has a diameter of 2 inches and is about 80 m to 50 m
This is a short-range antenna that detects an object at a distant position.

As shown in FIG. 2B, the long-distance antenna 11a has a radio wave radiating surface in front of the housing 21 (antenna 1).
1a) so that it is parallel to
The medium-range antenna 11b is mounted such that the radiation surface of the radio wave is inclined 2 ° counterclockwise with respect to the front of the housing 21. The short-range antenna 11c has a radio wave radiating surface
At an angle of 6 ° counterclockwise with respect to the front of the camera. The reason why the medium-range antenna 11b and the short-range antenna 11c are attached at an angle of 2 ° or 6 ° with respect to the front of the housing 21 is that the housing 21 has a rotation angle range of 16 °. In order to make the center of the detection angle range (for example, 14 ° and 22 ° in FIG. 4) of the detection target area of each antenna 11b and 11c coincide with the central axis of each antenna 11b and 11c at the center position. It is.

The long-distance antenna 11a has a detection distance of 1
The beam width of the radiated radio wave is set so as to have a spread of 0.6 ° (1.2 ° in total) to the left and right with respect to the center axis of the radiating surface of the radio wave in the range of 80 m to 120 m.
The medium distance antenna 11b has a detection distance of 120 m.
From 80 m, the width of the beam of the emitted radio wave is set to have a spread of 1.1 ° (2.2 ° in total) to the left and right with respect to the center axis of the radio wave radiation surface. Further, the short-range antenna 11c has a detection distance of 80 m to 5 m.
At 0 m, the beam width of the radiated radio wave is set to have a spread of 3 ° (6 ° in total) to the left and right with respect to the center axis of the radiating surface of the radio wave.

That is, three types of antennas 11a to 11a
c is the beam width of the radio wave of the short-range antenna 11c having the shortest detection distance, that is, the radiation angle range is 6 °, which is the widest among the three types of antennas, and the detection distance is the second shortest. Radiation angle range of the radio wave of the medium distance antenna 11b is the next widest, and the radiation angle range of the long distance antenna 11a having the longest detection distance is three kinds of antennas 11
It is the narrowest among a to 11c.

The housing 21 to which the three types of antennas 11a to 11c are attached is rotatably attached to a drive unit (not shown), and is rotated by a predetermined range, for example, an angle range of about 16 ° by the drive unit. It is installed as follows. The rotation of the drive unit is controlled by the processing device 13,
The position, size, and the like of the object are specified from the radiation directions of the radio waves from the antennas 11a to 11c and the reflected waves.

The processing device 13 includes antennas 11a to 11c.
The detection data is merged to extract an object, and it is determined whether or not the extracted object is an obstacle. Further, when the processing device 13 detects an obstacle, the processing device 13 displays information on the obstacle on the display panel 12, for example, a message for notifying the driver of the existence of the obstacle, and the like. When an obstacle is detected, information indicating the position and size of the obstacle is transmitted.

The integration center 14 monitors the road condition based on the detection data transmitted from the plurality of processing devices 13 and information on obstacles. FIG. 3 shows the contents of the obstacle detection processing in the obstacle detection device having the above configuration.
This will be described with reference to the flowchart of FIG.

First, the housing 21 is rotated by a predetermined angle range,
Radio waves are simultaneously emitted from the long-distance antenna 11a, the medium-distance antenna 11b, and the short-distance antenna 11c, and the respective reflected waves are received to detect an object within a certain range (S11 in FIG. 3).

The detection distance of the antenna and the radiation angle range of the radio wave are in an opposite relationship, and in order to increase the detection distance, it is necessary to narrow the beam width of the radio wave to be radiated, that is, the radiation angle range of the radio wave radiated from the antenna. There is.

By the way, when an object within a range of 180 m to 50 m of a 20 m wide road as shown in FIG. 4 is detected, a long distance, that is, about 180 m to 120 m from the antenna is detected.
The range of radio wave irradiation angles required to detect objects on distant roads is about 10 °, but it is necessary to detect objects on roads that are short distances, that is, about 80m to 50m away from the antenna. The irradiation angle range of the radio wave is about 22 °.

Therefore, if one antenna attempts to detect an object in the above detection target area, one antenna
Since the object within the detection target area 80 m to 50 m away is detected with the same beam width as that of the radio wave when detecting the object within the detection target area 80 m away,
In order to scan a detection target area 〜50 m away, 180
It is necessary to scan an angle range that is at least twice as large as the detection target area at a distance of m.

Normally, in an obstacle detection system, an antenna is mounted on a housing 21 and the housing 21 is rotated to radiate radio waves to a certain range. However, since the housing 21 has a certain amount of weight, it is difficult to rotate the housing 21 at a high speed, and it is difficult to scan a wide angle range in a short time. That is, if the rotation angle range is wide, it takes time to rotate the housing 21,
It takes time to detect an obstacle. If it is desired to quickly detect changes in road conditions and obstacles, as in a system for monitoring road conditions, it is necessary to solve the above problems.

In this embodiment, a plurality of antennas having different detection distances are used, and the beam width of the radio wave of the short distance antenna 11c for detecting an object at a short distance is wider than the beam width of the radio wave of the long distance antenna 11a. By doing so, it is possible to narrow the scanning angle range of the short-range antenna 11c. That is, since the rotation angle range of the housing 21 can be narrowed, the time required to scan a certain range can be reduced, and the detection time of an obstacle can be shortened.

FIG. 4 is an explanatory diagram of the detection distance of each antenna and the required detection angle range when detecting an object within a range of 180 m ahead of a 20 m wide road using three or four types of antennas. is there.

At the lower right corner of the 20 m wide road shown in FIG.
Antennas 11a to 11
c, the angle range of the detection target area 180 m to 120 m away from the installation position of the antennas 11 a to 11 c is about 10 °, and the angle range of the detection target area 120 m to 80 m ahead is about 14 °, 80 m The angle range of the detection target area 50 m ahead is about 22 °. In addition, the detection angle range when scanning the range of 50 m to 0 m is 27 °. In the following description, 180 m to 120 m, 120 m to 80 m
The case where three detection target areas m, 80 m to 50 m are scanned by three types of antennas will be described.

The beam width of the radio wave radiated from the long-distance antenna 11a in FIG. 3 is 0.6 ° to the left and right with respect to the center axis of the radiation surface of the radio wave (1.2 ° in total). Since the angle range is 10 °, the long-range antenna 11
The scanning angle range necessary for detecting an object on the road 180 m to 120 m ahead according to a is 10 ° ÷ 2−0.6 °.
= 4.4 °. Therefore, the housing 21 may be rotated left and right with a width of 4.4 ° or more and a total width of 8.8 ° or more about the position of 5 ° which is half of 10 ° of the detection angle range.

Since the medium-range antenna 11b is attached at an angle of 2 ° counterclockwise with respect to the long-distance antenna 11a, when the housing 21 is rotated, the medium-range antenna 11b is in the detection angle range. Assuming that it rotates equally to the left and right around the 7 ° position of the 14 ° center,
The beam width of the radio wave radiated from the medium-range antenna 11b is 1.1 to the left and right with respect to the center axis of the radiation surface of the radio wave.
° (2.2 ° in total), so the medium-range antenna 1
The scanning angle range necessary to detect an object on a road 120 m to 80 m ahead according to 1b is 14 ° ÷ 2−1.1 °
= 5.9 °. Therefore, the housing 21 may be rotated left and right with a width of 5.9 ° or more and a width of 11.8 ° or more as a center around a position of 7 ° which is half of 14 ° which is the detection angle range.

Since the short-range antenna 11c is mounted at an angle of 6 ° counterclockwise with respect to the long-range antenna 11a, when the housing 21 is rotated, the short-range antenna 11c is positioned within the detection angle range. 11 ° at the center of 22 °
, The beam width of the radio wave radiated from the short-range antenna 11c is 3 ° to the left and right with respect to the center axis of the radiation surface of the radio wave (6 ° in total).
°), so 80 m
The scanning angle range required to detect objects on the road in the range of 〜50 m is 22 ° ÷ 2-3 ° = 8 °. Therefore, the housing 21 is set at 11 which is half of the detection angle range of 22 °.
At least 8 ° to the left and right around °, 1 as a whole
What is necessary is just to rotate by a width | variety of 6 degrees or more.

From the above description, the housing 21 is moved left and right by 8 ° from the center of 5 ° of the detection angle range of 10 °, respectively.
By rotating the entire body at a width of 16 °, an object existing on the road at a distance of 180 m to 120 m by the long-distance antenna 11 a can be rotated by 120 m by the middle-distance antenna 11 b.
An object existing on a road within a distance of 80 m to 50 m can be detected by the short-range antenna 11c. This allows
The rotation angle range of the housing 21 to which the three types of antennas 11a to 11c are attached can be narrower than 22 ° which is the detection angle range necessary for detecting an object in the closest detection target area. The driving time for rotating the body 21 can be reduced, and the detection time for detecting an obstacle on the road can be reduced.

Further, the following effects can be obtained by making the detection distances of the antennas 11a to 11c different from each other. For example, a 6 inch antenna 11b for medium distance
By setting the beam width of the radio wave to a width suitable for the detection distance of 120 m to 80 m, and rotating the housing 21 by 16 °, the angle range that greatly exceeds the required detection angle range of 14 ° should not be scanned. Therefore, unnecessary data other than the detection target area is not often measured. Therefore, the processing for removing unnecessary data outside the detection target area from the detection data is reduced, so that the obstacle detection processing can be simplified as compared with the case where one antenna scans a wide angle range.

Referring back to FIG. 3, when the reflected waves are received by the respective antennas 11a to 11c, the received reflected waves are output to the processor 13 (S12). Processing device 1
3 is a long-distance antenna 11a, a medium-distance antenna 11
(b) The respective detection data obtained from the reflected waves of the short-range antenna 11c are merged to obtain detection data of an object within a certain range (S13).

When the detected data of the objects within a certain range is obtained, the objects having a certain speed or more are removed from the detected data, and the other objects are extracted as obstacles (S1).
4). This is because objects traveling at a certain speed or higher are judged to be not obstacles and are excluded from extraction targets, and objects (including stationary objects) below a certain speed are extracted as obstacles. is there.

Further, the detection data and data relating to the obstacle, for example, data such as the position and size of the obstacle are transmitted to the integration center 14 (S15). The integration center 14 determines the state of the road based on the received detection data of each point on the road based on the speed of the vehicle and the like based on whether or not the vehicle is flowing smoothly, and causes the display device to display the state of the road. Further, the presence / absence of an obstacle is determined from data on the obstacle, and the obstacle is displayed on the display device.

The processing device 13 determines the presence or absence of an obstacle based on the data on the obstacle extracted by the obstacle extraction processing in step S14 (S16). In the determination of the presence or absence of the obstacle, fixed objects such as guardrails installed along the road are excluded from the obstacles, and it is determined whether or not any other obstacle is detected. If it is determined in step S16 that there is no obstacle, step S1
Returning to step 1, the above-described processing is repeated.

If it is determined in step S16 that an obstacle is present, the process proceeds to step S17, where a message for notifying the driver that an obstacle is present ahead is created, and the message is displayed on the display panel 12. Let it. Thereafter, the process returns to step S11 to repeat the detection of the obstacle.

The above-described embodiment uses a plurality of antennas 11a to 11c having different detection distances. For example, the radiation angle range of the radio wave of the short-range antenna 11c is made wider than the radiation angle range of the long-range antenna 11a. Thus, the scan angle range (rotation angle range) when scanning the detection target region with the short-range antenna 11c can be narrower than the scan angle range required when scanning the detection target region with one antenna. it can. Accordingly, the scanning time of the antennas 11a to 11c required to detect an object within a certain range can be reduced as compared with the case where all distances are detected by one antenna, so that the object detection time can be reduced. This is particularly effective for a system that needs to detect an obstacle in a short time, such as a road obstacle detection system.

The above-described embodiment is a case where the present invention is applied to a road obstacle detection system. However, the present invention is not limited to this and can be applied to other than an obstacle detection system. For example, the present invention can be applied to a system for monitoring road conditions, that is, a system that measures the speed of an object using a sensor, a camera, or the like, and determines whether a vehicle is flowing smoothly or is congested. Applicable to systems.

In the above-described embodiment, the case where three types of antennas having different detection distances are used has been described. However, the present invention is not limited to this. May be used, or two or more antennas for long-distance antennas for detecting an object at a distance. In addition, the antenna used is not limited to the millimeter-wave band antenna,
A sensor or the like may be used, and various types of antennas such as a parabolic type and a planar type can be used.

Further, the method of changing the radiation direction of the radio wave of the antenna is not limited to the method of rotating the housing 21 to which the antenna is attached as described in the embodiment. A method of providing a means for controlling the reflection direction of the reflector (including a reflection direction control means including these means) may be used.

[0044]

According to the present invention, an antenna having a short detection distance is provided by using a plurality of antennas having different detection distances, for example, by making the radiation angle range of a radio wave of an antenna having a short detection distance wider than that of an antenna having a long detection distance. Can be narrowed. Thus, an object within a certain range can be detected in a short time.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an obstacle detection system.

FIGS. 2A and 2B are diagrams illustrating a configuration of an antenna. FIGS.

FIG. 3 is a flowchart of an obstacle detection process.

FIG. 4 is an explanatory diagram of a detection distance and a detection angle range of each antenna.

[Explanation of symbols]

 11a to 11c Antenna 12 Display Board 13 Processing Device 14 Integrated Center 21 Housing

Claims (13)

[Claims] 1. A radio wave is radiated from a plurality of antennas having different detection distances, and reflected waves of the radio wave are received by the plurality of antennas, respectively, and the radio waves are fixed based on the respective reflected waves received by the plurality of antennas. A method for detecting an object, comprising detecting an object within a range. 2. A radio wave is radiated from a plurality of antennas having different detection distances and radiation angle ranges of radio waves, and reflected waves of the radio waves are respectively received by the plurality of antennas. A method for detecting an object within a predetermined range based on a reflected wave. 3. The short-distance antenna according to claim 1, wherein the plurality of antennas comprise at least a short-distance antenna for detecting an object at a short distance from the antenna and a long-distance antenna for detecting an object at a distance farther from the antenna. 3. The method for detecting an object according to claim 1, wherein the radiation angle range of the radio wave is wider than the radiation angle range of the radio wave of the long-distance antenna. 4. The object detection method according to claim 1, wherein an object within a certain range is detected by changing a radiation direction of radio waves radiated from the plurality of antennas. 5. The antenna according to claim 1, wherein the plurality of antennas are mounted on a same housing, and detect an object within a predetermined range by rotating the housing.
The method for detecting the described object. 6. A radio wave is radiated from each of a plurality of antennas having different detection distances, and reflected waves of the radio wave are received by the plurality of antennas, respectively, and the radio waves are fixed based on the respective reflected waves received by the plurality of antennas. An obstacle detection method, comprising detecting an obstacle within a range. 7. The short-distance antenna according to claim 1, wherein the plurality of antennas comprise at least a short-distance antenna for detecting an object at a short distance from the antenna and a long-distance antenna for detecting an object at a distance farther from the antenna. 7. The obstacle detection method according to claim 6, wherein the radiation angle range of the radio wave is wider than the radiation angle range of the radio wave of the long-distance antenna. 8. The obstacle detecting method according to claim 6, wherein the plurality of antennas are for detecting an obstacle within a predetermined range of a road. 9. An obstacle for detecting an obstacle within a certain range based on a plurality of antennas having different detection distances and reflection waves of respective radio waves transmitted from the plurality of antennas and received by the plurality of antennas. An obstacle detection device comprising: an object detection unit. 10. An obstacle detecting apparatus according to claim 9, further comprising a radiation direction control means for changing a radiation direction of said plurality of antennas. 11. The short-range antenna according to claim 11, wherein the plurality of antennas comprise at least a short-range antenna for detecting an object at a short distance, and a long-range antenna for detecting an object at a distance longer than the short-range antenna. 10. The obstacle detection device according to claim 9, wherein the range is wider than the range of the radiation angle of the radio wave of the long-distance antenna. 12. The radio communication apparatus according to claim 10, wherein said plurality of antennas are mounted on a same casing, and said radiation direction control means rotates said casing by a predetermined angle range to radiate radio waves within a predetermined range. Obstacle detection device. 13. The obstacle detecting device according to claim 12, wherein mounting angles of said plurality of antennas to said housing are different from each other.