JP2946937B2 - Pulse laser distance measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse laser distance measuring apparatus for measuring a distance to a target by using a plurality of pulse lasers.

[0002]

2. Description of the Related Art A pulse laser distance measuring device irradiates a target with a laser pulse, receives a reflected pulse from the target, measures the time at which the laser pulse is emitted and the time until the reflected pulse returns, and measures this time. 1 round trip distance corresponding to the interval
Conventionally, this type of pulsed laser distance measuring apparatus is used to measure a range wider than a visual field corresponding to a divergence angle of a laser beam.
As shown in FIG. 2A, the distance is measured using a plurality of laser beams having a fixed laser beam intensity, or a single laser beam is mechanically scanned as shown in FIG. 2B. I was measuring the distance. This method is adopted because if a single laser beam is spread over a wide area and radiated, the intensity of the reflected light from the target is extremely reduced, and the reflected light cannot be detected sufficiently and is required. This is because distance measurement cannot be performed up to the distance.

[0003]

In such a conventional pulse laser distance measuring device, if the reflected pulse of the irradiated pulse laser can be sufficiently detected, the distance can be measured anywhere in the range where the reflected object is irradiated with the laser pulse. There is a drawback to do. That is, even when it is desired to measure a target in one direction, there is also a case where another object in another direction is measured, so that selective distance measurement cannot be easily performed. This disadvantage is remarkable when the laser light emitter of the distance measuring device is fixed to another structure. For example, when measuring the distance of an obstacle ahead (usually another traveling vehicle) with a pulse laser ranging device mounted and fixed on the traveling vehicle, the direction to be measured is the traveling direction of the vehicle, and the left curve It is more convenient to measure the distance on the left side in the case of, and on the right side in the case of the right curve. In such a case, the above-described pulse laser distance measuring apparatus has a disadvantage in that it detects other objects other than the traveling direction of the vehicle and measures the distance.

An object of the present invention is to provide a pulse laser distance measuring apparatus having means for mainly measuring a distance to an obstacle in a required direction in a distance measuring field of view. With the goal.

[0005]

The present invention SUMMARY OF], in the pulsed laser distance measuring device comprising a plurality of pulsed laser emission units each of the directional angle is different, the plurality of pulse laser light emitting portion
Of these, the light intensity of the pulse laser with
The control means to make the light intensity higher than the light intensity of the laser light emitting part
Characterized by comprising a stage.

Here, the number of the pulse laser light emitting portions mounted on the vehicle is three, and the directivity angles of the respective light emitting portions substantially coincide with the straight traveling direction, the right curve direction, and the left curve direction of the vehicle . by a signal corresponding to the steering angle of the vehicle of its
The light intensity of the light emitting unit may be controlled .

[0007]

The intensity distribution of each of the plurality of laser beams is changed according to the sign of the externally applied signal and the strength of the signal, and the distance to the obstacle in the required direction is measured with emphasis.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing this embodiment.

This embodiment, as shown in FIG. 1, is mounted on a vehicle and includes three pulsed laser light emitting portions. The directivity angles of the pulsed laser light emitting portions are defined as a straight traveling direction, a right curve direction, and a right curve direction of the vehicle. Each of the pulse laser light emitting units substantially coincides with the left curve direction, and includes means for changing the light intensity of the pulse laser emitted from the self light emitting unit in accordance with a signal corresponding to the steering angle of the vehicle.

Next, the operation of this embodiment will be described. The pulse laser distance measuring device 5 is mounted on a vehicle 6 and outputs three laser beams of a laser beam 1, a laser beam 2 and a laser beam 3 and receives an external signal 4. The external signal 4 is usually a signal corresponding to the steering angle of the steering wheel. FIG.
When the vehicle 6 goes straight as shown in FIG. 7A, the external signal 4 becomes (± 0), and the intensity of the laser beam 1 in the front direction is the strongest and the intensity of the left and right laser beams is relatively weak. FIG.
When the vehicle 6 curves to the right as in (b), the external signal 4 becomes (+) and the laser beam 2 becomes strongest,
Other laser beams are weakened. Conversely, when the vehicle 6 curves to the left as shown in FIG. 1C, the external signal 4 becomes (-) and the laser beam 3 becomes the strongest. That is, when the external signal 4 is (± 0), the distance is mainly measured in the front direction, and when the external signal 4 is (+), the distance is right from the front, and when the external signal 4 is (−), the distance is left from the front. Focus on distance measurement. In other words, the distance measuring ability is changed in each direction.

In the above-described embodiment, the case where three laser beams are used has been described. However, it is apparent that the number of laser beams can be set to a desired number based on operating conditions, performance specifications, and the like. .

[0012]

As described above, according to the present invention, by changing the intensity of each pulse laser beam with a plurality of pulse laser beams having different directivity angles by an external signal, an obstacle in a target direction can be obtained. This has the effect of selectively measuring the distance.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing the operation of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation of a conventional example.

[Explanation of symbols]

 1-3,7-9 laser beam 4 external signal 5,10,13 pulse laser ranging device 6,11,14 vehicle

Claims (2)

(57) [Claims] 1. A pulse laser distance measuring apparatus mounted on a vehicle and provided with a plurality of pulse laser light emitting units having different directivity angles, wherein a pulse having a directivity angle in a traveling direction of the vehicle among the plurality of pulse laser light emitting units. A pulse laser distance measuring device comprising a control unit for setting the light intensity of a laser to be higher than the light intensity of another pulse laser light emitting unit. 2. The method according to claim 1, wherein the number of the pulse laser light emitting units is three, and the directional angle of each light emitting unit is:
Straight direction of the vehicle, substantially coincides with the right curve direction and a left curve direction, the light emitting unit by a signal corresponding to the steering angle of that vehicle
2. A pulse laser distance measuring apparatus according to claim 1 , wherein the light intensity of said pulse laser is controlled .