JP3241906B2 - In-vehicle object detection device using laser light - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an on-vehicle object detecting device using a laser beam, and more particularly to a structure for discriminating a type of a detecting object based on a width of the detecting object.

[0002]

2. Description of the Related Art In recent years, other vehicles traveling ahead of an automobile,
An on-vehicle object detection device for detecting an obstacle has been proposed. This object detection device measures the direction and distance of another vehicle or obstacle located ahead, and issues, for example, a warning sound or the like when there is a decrease in the measured distance, as a danger of a rear-end collision.

[0005] An automobile 100 shown in FIG. 5 is equipped with an object detection device, and a light emitting section H1 of the object detection device is mounted on the automobile 100.
Emits a laser beam L1. The laser beam L1 is scanned in the direction of the arrow 90 and is irradiated on the object 101 traveling ahead. When the object 101 is, for example, a four-wheeled vehicle or a two-wheeled vehicle, the laser beam L1 is reflected by a reflector provided at the rear of the four-wheeled vehicle or the two-wheeled vehicle. The light is received by a light receiving unit (not shown) of a certain target object device.

[0004] The object detection device calculates the distance to the object 101 based on the delay time from the emission of the laser beam L1 to the reception thereof. Further, the position direction of the target object 101 can be detected based on the scanning direction of the laser beam L1 applied to the target object 101.

[0005]

The conventional on-vehicle object detection apparatus has the following problems. As mentioned above,
The distance and the position direction to the object 101 can be detected based on the delay time from the emission of the laser light to the reception of the reflected light and the scanning direction of the laser light L1. However, it is necessary to recognize the type of the target object 101, for example, whether the detected target object 101 is a four-wheeled vehicle or a two-wheeled vehicle, and whether it is a roadside reflector or a stationary object such as a signboard. Can not. For this reason, there has been a problem that appropriate measures cannot be taken according to the target object.

[0006] For example, in a system in which it is determined that there is a danger of a rear-end collision and a warning sound is issued when the distance to an object located ahead is smaller than a predetermined reference distance, the warning sound is frequently generated. In such a case, the user may become less accustomed to the warning sound due to getting used to. A two-wheeled vehicle or the like traveling ahead has a high risk of a rear-end collision, so it is necessary to activate the alarm sufficiently. However, a roadside reflector or the like has a relatively low risk, and it is desirable to suppress the alarm sound. However, since the type of the target object cannot be recognized, the alarm sound cannot be controlled according to the target object.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an on-vehicle object detection apparatus using a laser beam, which can perform an accurate operation according to the detection target by recognizing the type of the detection target.

[0008]

According to the present invention, there is provided an on-vehicle object detecting apparatus using a laser beam, which emits light while scanning the laser beam toward an object to be detected, and a scanning position for detecting a scanning direction of the laser beam. A detecting unit, a light receiving unit that receives the reflected light of the laser light from the detection target and outputs a light receiving signal, a distance detecting unit that detects a distance to the detection target based on the light receiving signal from the light receiving unit, and a scanning position detecting unit. direction detecting unit for detecting the direction of the detection object based on a scanning direction of the detected laser beam, the self
A relative speed detection unit that detects a relative speed between the vehicle and a detection target,
Based on the direction of the detection target detected by the direction detection unit, and the distance to the detection target detected by the detection target unit,
A detection target width detection unit that detects the width of the detection target, a type determination unit that determines the type of the detection target based on the relative speed and the width of the detection target, and a distance between the vehicle and the detection target is set.
Activates the alarm when the distance falls below the set reference distance.
Object for in-vehicle use using a laser beam with an alarm control unit
A detection device, wherein the vehicle width is set, and the type determination unit
The vehicle width setting based on the type of detection target
Control the operating state of the alarm by changing the setting
It is characterized.

[0009]

[0010]

According to the present invention, the type of the object to be detected is determined based on the relative speed and the width of the object to be detected , and the width of the own vehicle is set.
And changes the set width of the vehicle based on the type of detection target.
By controlling the alarm, the operating state of the alarm is controlled.

Therefore , the type of the detection target can be easily recognized, and the detection target thus recognized can be easily recognized.
Detection target may overlap on the travel line of the own vehicle according to the type of
Sex can be changed. In other words, the vehicle width is
If it is changed, the detection target may overlap the travel line of the own vehicle
When the vehicle height is increased and the vehicle width is changed to narrow, the detection target becomes
The possibility of overlapping on the vehicle's travel line is reduced. This allows
Depending on the type of the detection target, the detection target
The possibilities can be changed.

[0012]

[0013]

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a device for detecting an object mounted on a vehicle using a laser beam according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an object detection device according to the present embodiment.
The control circuit 4 outputs a light emission timing signal to the light emitting unit 5. The light emitting unit 5 includes a laser diode driving circuit 6, a laser diode 8, and a scanning device 10,
The light emission timing signal is taken into the laser diode drive circuit 6 in the light emitting section 5. The laser diode drive circuit 6 causes the laser diode 8 to emit laser light according to the light emission timing signal.

The scanning device 10 repeatedly scans the laser beam within a predetermined measurement range. The scanning direction of the laser light is detected by the scanning position detecting device 12 and is provided to the control circuit 4. The control circuit 4 detects the direction of the detection target as a direction detection unit based on the scanning direction of the laser light.

The laser light is reflected by the object to be detected, and the reflected light is received by the photodiode 14 of the light receiving section 13, a light receiving signal is output through the light receiving circuit 16, and is taken into the control circuit 4. The control circuit 4 fetches the received light signal in synchronization with the emission timing of the laser light. Then, the control circuit 4 functions as a distance detection unit to measure a delay time from emission of the laser light to reception of the reflected light, and calculate and output a distance to the detection target based on the delay time.

The direction of the detection target and the distance to the detection target obtained by the control circuit 4 as described above are taken into the type determination circuit 2. Then, the type determination circuit 2 determines the relative speed between the vehicle and the detection target based on the direction and the distance of the detection target. The relative speed can be obtained by measuring a temporal change in the distance to the detection target.

The type determination circuit 2 detects the width of the detection target based on the direction and distance of the detection target. FIG. 2 shows a measurement point to be detected represented by two-dimensional coordinates of a direction and a distance. As shown in the figure, when the measurement point suddenly changes beyond a predetermined threshold,
It is recognized that the range K1 indicates the width of the detection target. The range K1 is a value on the scanning direction axis shown in FIG. 2, and the width of the detection target can be obtained from the value of K1 and the scanning speed of the laser beam.

It should be noted that the value of K1 may be obtained using a time axis instead of the scanning direction axis in FIG. Further, in the present embodiment, the entire width of the detection target is detected, but the width of the detection target vehicle may be obtained based on a reflector provided behind a two-wheeled or four-wheeled vehicle. .

Thus, the relative speed with respect to the detection target and the width of the detection target are obtained, and the type of the detection target is determined based on these. In the present embodiment, the detection targets are classified and determined into four types of “roadside reflector”, “stationary object other than roadside reflector”, “two-wheeled vehicle”, and “four-wheeled vehicle”. FIG. 3 shows an example of criteria for determining the type of a detection target. In the width of the detection target, “S” indicates that the length is less than 0.6 m,
“B” indicates 0.6 m or more. In the relative speed, “S” indicates less than 30% of the own vehicle speed, and “B” indicates 30% or more of the own vehicle speed. The own vehicle speed is measured by the own vehicle speed detector 18 in FIG.

As shown in FIG. 3, the width of the object to be detected is 0.6
If it is less than “S” and the relative speed is 30% or more of the own vehicle speed “B”, it is determined that the detection target is the roadside reflector. When the width of the detection target is 0.6 or more “B” and the relative speed is 30% or more of the own vehicle “B”, it is determined that the detection target is a stationary object other than the roadside reflector, for example, a signboard or the like. I do.

If the width of the detection target is less than 0.6 "S" and the relative speed is less than 30% "S" of the own vehicle, it is determined that the detection target is a two-wheeled vehicle. If the width of the detection target is 0.6 or more “B” and the relative speed is “S” of less than 30% of the own vehicle, it is determined that the detection target is a four-wheeled vehicle.

The type of the object to be detected is determined according to the above criteria. In the present embodiment, the detection targets are classified into four types and determined, but may be determined by classifying them into three or less or five or more. Although the type is determined based on the two feature amounts of the detection target width and the relative speed, the determination may be made based on the other feature amounts or in consideration of the other feature amounts. Good. For example, the control circuit 4
, The distance to the detection target, the direction of the detection target, and the like are treated as independent feature amounts, and the type can be determined in consideration of these.

Further, the steering angle information from the steering angle sensor, the yaw rate information from the G sensor, and the like are input to the type determination circuit 2 (FIG. 1), and the type of the detection target is determined in consideration of these. Good. It is possible to recognize that the road is curved in accordance with such information, and for example, it is easy to determine the roadside reflector provided at the curve. That is, the steering operation of the own vehicle can be recognized by the steering angle information, and the inclination and the like of the own vehicle can be recognized by the yaw rate information. From such steering operation and the inclination of the vehicle, it is possible to grasp the road condition of whether or not the vehicle is curving, and this is one of the judgment factors that the detection target is the roadside reflector.

FIGS. 4A and 4B show another embodiment in which the type of a detection target is determined based on the width, relative speed, and the like of the detection target.
Here is an example that uses a membership function as shown in (1).
For example, in FIG. 4A, it is assumed that the width of the detection target is a (m). In this embodiment, the object to be detected is “a stationary object other than the roadside reflector” in order to detect an object with high probability.
Is determined. In FIG. 4B, assuming that the relative speed is b (%) of the own vehicle, the detection target is determined to be “a roadside reflector” or “a stationary object other than a roadside reflector”. Therefore, it is determined that the detection target is “a stationary object other than the roadside reflector” that satisfies both the conditions of FIGS. 4A and 4B.

[0026] By the type of the detected object Te good Unishi of this can be easily determined, thereafter, it is possible to perform an accurate operation according to the type. Next, an embodiment in which the operation of an alarm device for preventing a rear-end collision is controlled according to the type of the detection target will be described. The alarm 22 shown in FIG. 1 is provided when the distance to the detection target located on the traveling line of the own vehicle is smaller than the reference set distance.
It judges that there is danger of rear-end collision and emits an alarm sound. However, if the warning sound is generated frequently, the user may become less accustomed to the warning sound due to familiarity.

For this reason, the alarm control circuit 20 suppresses the operation of the alarm 22 according to the type of the detection target.
Specifically, the operation of the alarm 22 is controlled by changing the set value of the vehicle width. If the set value of the vehicle width is changed to a small value, the possibility that the detection target overlaps the traveling line of the vehicle decreases, and the operation of the alarm 22 is suppressed. Conversely, if the set value of the vehicle width is increased, the possibility that the detection target overlaps the traveling line of the vehicle increases, and the operation frequency of the alarm 22 also increases.

FIG. 4C shows a specific example of the control of the alarm 20. When it is determined that the detection target is the roadside reflector, the set value of the vehicle width is set to “−1 m” to suppress the alarm sound. In addition, when the detection target is determined to be a stationary object other than the roadside reflector, the vehicle width is “+1.0 m”, when it is determined to be a two-wheeled vehicle, “+2.0”, and when it is determined to be a four-wheeled vehicle, “+0.5 m” is set so that the frequency of occurrence of the alarm sound increases.

It should be noted that other numerical values may be used as the numerical values shown in FIG. 4C. Further, in order to control the operation of the alarm device 20, the reference set distance from the detection target may be changed.

[0030]

According to the present invention, the type of the detection target is determined based on the relative speed and the width of the detection target, and the width of the own vehicle is determined.
And set the width of the vehicle set based on the type of detection target.
By changing, the operation state of the alarm is controlled.

That is, according to the type of the detection target,
By changing the possibility that the detection target overlaps the travel line,
Alarm frequency according to the type of detection target.
It becomes possible to control. This allows you to get used to
It is possible to prevent a decrease in alertness
You.

[0032]

[0033]

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of an on-vehicle object detection apparatus using a laser beam according to the present invention.

FIG. 2 illustrates a measurement point to be detected in two-dimensional coordinates of a direction and a distance.

FIG. 3 is a table showing criteria for determining the type of a detection target.

FIGS. 4A and 4B show membership functions used to determine the type of a detection target, and C shows a specific example of alarm device operation control.

FIG. 5 is a diagram schematically illustrating a scanning type vehicle-mounted object detection device using a laser beam.

[Explanation of symbols]

 2 ···· Type determination unit 4 ··· Control unit 6 ···· Laser diode drive circuit 8 ···· Laser diode 10 ···· Scanning device 12 ····· Scan Position detector 14 Photodiode 16 Light receiving circuit 18 Vehicle speed detector 20 Alarm control circuit 22 Alarm

Continuation of the front page (56) References JP-A-3-132434 (JP, A) JP-A-1-213593 (JP, A) JP-A-5-280934 (JP, A) JP-A-5-164836 (JP) , A) JP-A-4-158293 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S 7/48 G01S 17/00-17/88

Claims (1)

(57) [Claims] 1. A light emitting unit that emits laser light while scanning toward a detection target, a scanning position detection unit that detects a scanning direction of the laser light, receives reflected light of the laser light from the detection target, and outputs a light reception signal. A distance detecting unit that detects a distance to a detection target based on a light receiving signal from the light receiving unit, and a direction detecting unit that detects a direction of the detection target based on a scanning direction of the laser beam detected by the scanning position detecting unit. A relative speed detection unit that detects a relative speed between the vehicle and the detection target, a direction of the detection target detected by the direction detection unit, and a distance to the detection target detected by the detection target unit,
Detection target width detector for detecting the width of the detection target, the relative speed and the type determining portion that determines the type of the detection object of the detection target based on the width, the distance between the detection object and the vehicle, set a reference Set distance
An on-vehicle object detection device using a laser beam , comprising: an alarm control unit that activates an alarm when it falls below.
The vehicle width is set and the detection target determined by the type determination unit is determined.
By changing the setting of the vehicle width based on the type,
An on-vehicle object detection device using laser light, characterized by controlling an operation state of an alarm .