JP2002162461A - Periphery detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine whether a target is a single object or an object having parallel faces or an object having an oblique face using a periphery detection device. SOLUTION: This device is provided with a distance measuring device 100 having a signal transmission circuit 4 and a signal receiving circuit 5, and a distance-measuring device 200, having similarly a signal transmission circuit 8 and a signal receiving circuit 9. A signal is transmitted from the signal transmission circuit 4 in the distance-measuring device 100, and a reflected signal from the target is received by the signal reception circuits 5, 9 in the two distance-measuring devices 100, 200, respectively. Also, a signal is transmitted from the signal transmission circuit 8 inside the distance-measuring device 200, and the reflected signal from the target is received by the signal reception circuits 5, 9 in the two distance-measuring devices 100, 200, respectively. In this way, distance calculation circuits 7, 11 calculate four kinds of distance, based on the four kinds of signals received in this way. A target determination circuit 13 determines whether the target is a single object or an object, which has parallel faces or an object having an oblique face from the four distance calculation results, and calculates respective distances to each object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an environment detecting device for measuring a distance from a time required for transmitting and receiving signals to a target.

[0002]

2. Description of the Related Art There is known an environment detecting device which transmits a sound wave, light or electromagnetic wave, measures a time until a reflected wave from a target returns, and detects a distance to the target. The mechanism of the conventional surroundings detection device will be briefly described below.

FIG. 9 is a diagram showing the relationship between a conventional surroundings detection device and a target. The conventional surrounding detecting device includes two distance measuring devices 1 and 2 installed at a predetermined distance from each other. The distance measuring devices 1 and 2 each include a signal sending circuit and a signal receiving circuit. As shown in FIG. 9, the distance between the distance measuring device 1 and the target 3 is L1, and the distance between the distance measuring device 2 and the target 3 is L2. The distance measuring device 1 sends a signal toward the target 3, receives a signal reflected by the target 3, and detects a time required for transmission / reception, thereby calculating a distance L1 to the target 3. . By the same procedure, the distance measuring device 2 calculates the distance L2 to the target 3.

A method for calculating the position of the target 3 will be described with reference to FIG. Since the distance between the target 3 and the distance measuring device 1 is L1, the target 3 is on a circle having a radius L1 centered on the distance measuring device 1. For the same reason, the target 3 is also on a circle having a radius L2 centered on the distance measuring device 2. That is, the position of the target 3 can be calculated as being at the position X where the two circles intersect.

The method of calculating the position of the target 3 described above is shown in FIG.
As shown in FIG. 10 and FIG. 10, it can be used only when the target 3 is a single object. This is the target 3
FIGS. 11 and 1 show a case where is a planar object such as a wall.
2 will be described. In this specification, a single object refers to an object that does not have a predetermined spread surface such as a wall, such as a telephone pole.

FIG. 11 is a diagram showing a case where the target 3 is a plane parallel to a line connecting the two distance measuring devices (hereinafter, simply referred to as a “parallel plane”). That is, the distance measuring device 1
The distance L1 between the distance measurement device 2 and the target 3 is equal to the distance L1 between the distance measurement device 2 and the target 3. When the position of the target 3 is calculated by the method described above, the radius L around the distance measuring device 1 is calculated.
The position X at which the circle 1 and the circle having the radius L2 centered on the distance measurement device 2 intersect is calculated as the position of the target 3. Therefore, an error ΔX occurs between the actual distance to the target 3 and the calculated distance.

In FIG. 11, the case where the target 3 is a parallel surface has been described. However, the same applies to the case where the target 3 is not parallel to the line connecting the two distance measuring devices but is inclined, as shown in FIG. An error occurs between the actual distance to the target 3 and the calculated distance.

[0008]

As described above, in the conventional detection device, when the target is a single object, the position of the target can be correctly detected, but the target is not a surface. In the case of a shape-like object, a measurement error occurred. Even if the target is a planar object, it is necessary to determine the type of the target in order to accurately detect the distance and the azimuth to the target, but with a conventional detection device, the type of the target is determined. I couldn't do that.

An object of the present invention is to determine whether a target is a single object, a planar object such as a wall, and even if the target is a planar object, is it a parallel surface or a non-parallel oblique surface? The object of the present invention is to provide a surroundings detecting device capable of determining the following.

[0010]

FIG. 1 shows an embodiment of the present invention.
The present invention will be described with reference to FIG. (1) The invention according to claim 1 is based on the first and second transmitting means 4 and 8 for transmitting a signal to a target, and from the target transmitted from the first and second transmitting means 4 and 8 First and second receiving means 5, 9 for receiving a reflected signal reflected
And the first and second receiving means 5 and 9 respectively receive the signal from the first transmitting means 4 to obtain first and second detection signals, and the signal from the second transmitting means 8 Control means for receiving third and fourth detection signals respectively received by the first and second receiving means 5 and 9, and determination means for determining the shape of the target based on the first to fourth detection signals 13 achieves the above object. (2) According to a second aspect of the present invention, in the surroundings detecting apparatus according to the first aspect, the determination means 13 has a predetermined surface such as a wall based on the first to fourth detection signals. While judging whether it is a wall-shaped object or an object without a predetermined surface,
Further, it is characterized in that it is determined whether or not the predetermined surface is parallel or inclined with a line connecting the first and second transmitting / receiving means. (3) According to a third aspect of the present invention, in the surroundings detecting apparatus according to the first or second aspect, the computing device further includes computing means for computing a distance to the target based on the first to fourth detection signals. It is characterized by the following.

[0011]

According to the present invention, the following effects can be obtained. (1) According to the first aspect of the present invention, the surrounding detecting device transmits the signal to the target by the first and second transmitting means;
First and second receiving means for receiving reflected signals transmitted from the first and second transmitting means and reflected from the target; and receiving first and second signals from the first transmitting means. Means for receiving first and second detection signals, respectively, and transmitting the signal from the second transmitting means to the first and second detection signals.
And a determination unit for determining the shape of the target based on the first to fourth detection signals. The shape can be determined. (2) According to the second aspect of the present invention, based on the first to fourth detection signals, whether the target is a wall-shaped object having a predetermined surface such as a wall or an object having no predetermined surface. And whether the predetermined surface is parallel or inclined to the line connecting the first and second transmitting and receiving means. (3) According to the third aspect of the invention, the distance to the target can be accurately calculated according to the type of the detected target.

In the section of the means for solving the above-mentioned problems, the present invention is associated with FIG. 1 of the embodiment for easy explanation of the present invention, but the present invention is limited to the embodiment. Not something.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration when the present invention is applied to a vehicle surroundings detection device. The vehicle surrounding detection device includes first and second signal transmission circuits 4 and 8 for transmitting non-directional signals such as sound waves, light, and electromagnetic waves.
And first and second signal receiving circuits 5 and 9 for receiving a reflected signal from the target and converting the signal to an electric signal, and transmitting a signal to signal transmitting circuits 4 and 8 based on the received information of the reflected signal. A first and second delay time detecting circuits 6 and 10 for detecting a time from sending a signal to receiving a reflected signal;
And first and second distance calculation circuits 7 and 11 for calculating distances based on the times detected by the second and delay time detection circuits 6 and 10, and first and second distance calculation circuits 7 and 11 A target determination circuit for determining the type of the target based on the calculated distance; The control circuit 12 and the target determination circuit 13 are each constituted by a peripheral circuit such as a CPU and a memory.

The distances calculated by the first and second distance calculation circuits 7 and 11 are distances as the shortest path from when a signal is transmitted to when the signal is received, and are a distance between the distance measuring device and the target. Is different from the actual distance.

Among the above-mentioned circuits, the first signal transmitting circuit 4, the first signal receiving circuit 5, the first delay time detecting circuit 6, and the first distance calculating circuit 7 constitute one set. Thus, the distance measuring device 100 is configured. Similarly, the second signal transmitting circuit 8, the second signal receiving circuit 9, the second delay time detecting circuit 10, and the second distance calculating circuit 11 form a set to form the distance measuring device 200. Make up. Accordingly, the vehicle peripheral device according to the present invention includes two distance measuring devices 100 and 200 having the same function and configuration.

With reference to FIGS. 1 to 3, the processing procedure for determining the shape of the target and calculating the distance will be described. The flowchart in FIG. 3 shows a processing procedure based on a distance calculation program executed by the CPU of the control circuit 12. Time point t1 in FIG.
At 0, a signal is transmitted from the first signal transmission circuit 4 in the distance measuring device 100 in accordance with an instruction from the control circuit 12 (step S1). At this time, the control circuit 12 transmits a transmission start signal to the delay time detection circuits 6 and 10. Thereby, the delay time detection circuits 6 and 10 start time measurement. After the signal transmitted from the signal transmission circuit 4 is reflected by the target, the signals are received by the signal receiving circuits 5 and 9 in the distance measurement devices 100 and 200 as reflected signals at time points t11 and t12. . The signal received by the signal receiving circuit 5 is sent to the delay time detecting circuit 6, and the time from signal transmission to reception is detected. The distance is calculated by the distance calculation circuit 7 based on this time. The signal received by the signal receiving circuit 9 in the distance measuring device 200 is sent to the delay time detecting circuit 10, and the distance is calculated by the distance calculating circuit 11 as in the processing of the distance measuring device 100.

When the control circuit 12 determines that the reception of the first and second reception signals has been completed (step S2), it sends a signal transmission command to the second signal transmission circuit 8 in the distance measuring device 200, and a time t20. , A signal is sent from the signal sending circuit 8 (step S3). After the signal transmitted from the signal transmission circuit 8 is reflected by the target, the signals are transmitted at time points t21 and t21.
At 22, each of the signal receiving circuits 5 and 9 in the distance measuring devices 100 and 200 receives the reflected signal as a reflected signal. In this case, the distances are calculated in the distance calculation circuits 7 and 11, respectively, as in the case where the signal is transmitted from the signal transmission circuit 4 in the distance measurement device 100.

With the above processing, four types of distances are obtained. That is, sent from the distance measuring device 100,
A total of a distance calculated based on the signals received by the distance measuring devices 100 and 200 and a distance calculated from the signals transmitted from the distance measuring devices 200 and received by the distance measuring devices 100 and 200, Kind. When the control circuit 12 determines that the reception of the third and fourth reception signals is completed (step S4), the distance calculation circuits 7 and 11
Sends the four distance calculation results to the target determination circuit 13 (step S5).

The target determining circuit 13 determines whether the target is a single object, has a parallel surface, or has a non-parallel oblique surface based on the four types of distances described above. The method of determining the target will be described below.

First, a case where the target is a single object will be described with reference to FIG. The distance between the distance measuring device 100 and the target is L1, and the distance between the distance measuring device 200 and the target is L2.

FIG. 4A shows a case where a signal is transmitted from the distance measuring device 100. The distance calculated when the reflected signal from the target 3 is received by the distance measuring device 100 is 2 ×
L1. The distance calculated when the distance measurement device 200 receives the reflected signal is L1 + L2. On the other hand, FIG. 4B shows a case where a signal is transmitted from the distance measuring device 200. The distance calculated when the reflected signal is received by the distance measuring device 100 is L1 + L2. The distance calculated when the reflected signal is received by the distance measuring device 200 is:
2 × L2. FIG. 4C shows a list of the measurement results.

As shown in FIG. 4 (c), when the target 3 is a single object, the respective distances calculated when the distance measuring device that has transmitted the signal receives the reflected signal are added. (2 × L1 + 2 × L2) and the respective distances calculated when a distance measuring device different from the distance measuring device that sent the signal receives the reflected signal (L1
+ L2 + L1 + L2).

The method of calculating the position when the target 3 is determined to be a single object is the same as the method of FIG. 10 described using the conventional detection device, and therefore the description is omitted here. I do.

In the case where the target 3 is a planar object such as a wall, and its surface is placed parallel to a line connecting the distance measuring device 100 and the distance measuring device 200 (parallel surface),
This will be described with reference to FIG. The distance between the distance measuring device 100 and the distance measuring device 200 and the surface of the target 3 are both L1,
The shortest distance when the signal transmitted from one distance measuring device is reflected on the surface of the target 3 and received by the other distance measuring device is L2. The line connecting the distance measuring device 100 and the distance measuring device 200 is a line connecting the signal transmitting surfaces of the signal transmitting circuit 4 and the signal transmitting circuit 8 or the signal receiving circuit 5 and the signal receiving circuit 9. Are line segments connecting the respective signal receiving surfaces.

FIG. 5A shows a case where a signal is transmitted from the distance measuring device 100. The distance calculated when the reflected signal from the target 3 is received by the distance measuring device 100 is 2 ×
L1. The distance calculated when the distance measurement device 200 receives the reflected signal is L2. On the other hand, FIG.
(B) is a case where a signal is transmitted from the distance measuring device 200. The distance calculated when the reflected signal is received by the distance measuring device 100 is L2. The distance calculated when the reflected signal is received by the distance measuring device 200 is 2 × L1
It is. FIG. 5C shows the measurement results.

When the target 3 has parallel surfaces, the distances calculated when the distance measuring device that has transmitted the signal receives the reflected signal are added (2 × L1 +
2 × L1) does not coincide with the sum of the respective distances calculated when a distance measuring device different from the distance measuring device that sent the signal receives the reflected signal (L2 + L2), and is always small. Value. Further, each distance (2 × L1) calculated when the distance measuring device that has transmitted the signal receives the reflected signal always coincides.

When the target 3 is determined to be a parallel surface, half of the distance (2 × L1) calculated when the distance measuring device that sent the signal receives the reflected signal is equal to the target. 3 is the actual distance L1.

Finally, the case where the target 3 has a wall-like surface and an oblique surface 3S will be described with reference to FIG. The distance between the distance measuring device 100 and the surface 3S is L1, the distance between the distance measuring device 200 and the surface 3S is L2, and a signal transmitted from one of the distance measuring devices is reflected on the surface 3S of the target 3 and the other. The shortest distance when received by the distance measuring device is L
3 is assumed.

FIG. 6A shows a case where a signal is transmitted from the distance measuring device 100. The distance calculated when the reflected signal from the surface 3S of the target 3 is received by the distance measuring device 100 is 2 × L1. The distance calculated when the distance measuring device 200 receives the reflected signal is L3. on the other hand,
FIG. 6B shows a case where a signal is transmitted from the distance measuring device 200. The distance calculated when the reflected signal is received by the distance measuring device 100 is L3. Distance measuring device 20
The distance calculated when a reflected signal is received at 0 is 2 ×
L2. FIG. 6C shows the measurement results.

In the case where the target 3 has the oblique surface 3S, similarly to the case of the parallel surface, the respective distances calculated when the distance measuring device which has transmitted the signal receives the reflected signal are added. The sum (2 × L1 + 2 × L2) is the same as the sum (L3 + L3) of the respective distances calculated when a distance measuring device different from the distance measuring device that sent the signal receives the reflected signal. Without this, the value is always small.
In addition, the distances 2 × L1 and 2 × L2 calculated when the distance measuring device that has transmitted the signal receives the reflected signal do not match.

When it is determined that the target 3 has the oblique surface 3S, the distance measuring device that has transmitted the signal examines the magnitude relationship between the respective distances calculated when the reflected signal is received. , The actual distance to the target 3 can be calculated. Referring to FIG. 6, the distance calculated by the distance measuring device 100 is 2 × L1, and the distance calculated by the distance measuring device 200 is 2 × L2. The magnitude relationship between the two is examined and the smaller value is extracted. Here, it is 2 × L1. Half of this distance, that is, L1 is the actual distance to the target 3.

The processing procedure of the target determination circuit 13 will be described with reference to FIG. This processing procedure is performed by the target determination circuit 13.
Is executed by a program stored in the CPU. If it is determined in step S11 that all of the four distance calculation results described above have been input, step S11 is performed.
Proceeding to 12, it is determined whether the target is a single object or a planar object. As described above, the sum of the respective distances calculated when the distance measuring device that transmitted the signal receives the reflected signal is different from the distance measuring device that is different from the distance measuring device that transmitted the signal. When the sum of the distances calculated when the signal is received matches the sum,
It is determined that the target is a single object, and the process proceeds to step S14. If they do not match, they are parallel or oblique.

If it is determined in step S12 that the object is not a single object, the process proceeds to step S13. Step S
At 13, it is determined whether the plane is parallel or oblique.
If the distances calculated when the distance measuring device that has sent the signal receives the reflected signal match, it is determined that the planes are parallel surfaces, and the process proceeds to step S15. If they do not match, it is an oblique surface, and the process proceeds to step S16. In step S14, the distance to a single object that is the target 3 is calculated. As described above, the distance between one distance measuring device and the target 3 is half the distance calculated when the distance measuring device transmits a signal and receives a reflected signal. In step S15, the distance to the target 3 having a parallel surface is calculated. As described above, half of the distance calculated when the distance measuring device that has transmitted the signal receives the reflected signal is the distance to the target 3. In step S16, the shortest distance to the target 3 having an oblique surface is calculated. As described above, the distance measuring device that has transmitted the signal examines the magnitude relationship of the distances calculated when the reflected signal is received, and half of the smaller distance is the distance to the target.

As described above, by using the two distance measuring devices 100 and 200 to obtain four types of distances calculated based on the four types of reflected signals from the target 3, the target 3 becomes a single target. It is possible to determine whether the object has a parallel surface or an oblique surface, and calculates the distance to the target 3 according to the type of the target 3 according to the determination results. be able to.

In the above description, the signal transmitting circuit in the distance measuring device transmits a non-directional signal such as a sound wave. However, the signal transmitting circuit may transmit a directional signal such as a laser beam while scanning. . Further, the surrounding detection device described above determines the type of the target and calculates the distance to the target. However, only the determination result of the type of the target may be output, or only the distance to the target may be output.

FIG. 8 shows an example in which the above-described surrounding detection device is installed at the rear end of the vehicle 14. The distance measuring device 100 including the signal transmitting circuit 4 and the distance measuring device 200 including the signal transmitting circuit 8 are installed at a rear end of the vehicle 14 at a certain distance. The distance to be measured is the shortest distance between the rear end of the vehicle 14 and the target 3. In addition, you may install a surroundings detection apparatus in the side part or front end part of a vehicle.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a surroundings detection device according to the present invention.

FIG. 2 is a diagram showing timings of transmitting and receiving signals in the surroundings detection device shown in FIG. 1;

FIG. 3 is a flowchart showing a procedure example from when a signal is transmitted to when four distance calculation results are transmitted to a target determination circuit;

FIG. 4 is a diagram for explaining a method of determining a target when the target is a single object;

FIG. 5 is a diagram for explaining a method of determining a target when the target has parallel surfaces;

FIG. 6 is a diagram for explaining a method of determining a target when the target has an oblique surface;

FIG. 7 is a flowchart showing a procedure for determining a type of a target from four distance calculation results.

FIG. 8 is a diagram showing a configuration when the surroundings detection device according to the present invention is installed at the rear end of a vehicle.

FIG. 9 is a diagram showing a conventional surroundings detection device.

FIG. 10 is a diagram for explaining a method for calculating the position of a target by a conventional surroundings detection device when the target is a single object.

FIG. 11 is a diagram for explaining a method for calculating the position of a target by a conventional surroundings detection device when the target is a parallel surface;

FIG. 12 is a diagram for explaining a method for calculating the position of a target by a conventional surrounding detection device when the target is an oblique surface;

[Explanation of symbols]

1-2, 100, 200 ... distance measuring device, 3 ... target, 3
S: diagonal surface, 4, 8: signal transmission circuit, 5, 9: signal reception circuit, 6, 10: delay time detection circuit, 7, 11: distance calculation circuit, 12: control circuit, 13: target determination circuit , 14
…vehicle

Claims (3)

[Claims] 1. First and second transmitting means for transmitting a signal to a target, and receiving a reflected signal transmitted from the first and second transmitting means and reflected from the target. First and second
Receiving means for receiving signals from the first transmitting means by the first and second receiving means to obtain first and second detection signals, respectively, and a signal from the second transmitting means. The first
Control means for receiving third and fourth detection signals respectively received by the first and second reception means, and determination means for determining the shape of the target based on the first to fourth detection signals. A surroundings detection device characterized by the above-mentioned. 2. The surroundings detection device according to claim 1, wherein the determination unit determines whether the target is a wall-shaped object having a predetermined surface such as a wall based on the first to fourth detection signals. Determining whether the object does not have the predetermined surface, and further determining whether the predetermined surface is parallel or inclined to a line connecting the first and second transmission / reception means. Ambient detection device. 3. The surroundings detecting device according to claim 1, further comprising a calculating means for calculating a distance to the target based on the first to fourth detection signals. .