JP2874669B2 - Laser radar - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser radar, and more particularly, to optical axis adjustment.

[0002]

2. Description of the Related Art Conventionally, when an optical axis of a light transmitting axis and a light receiving axis is adjusted in a laser radar, first, an adjustment is performed so that light from a light transmitting side is applied to a center of a sight. The optical axis has been adjusted by using an autocollimator so that the center of the detector provided on the light receiving side is aligned with the center of aiming.

[0003]

However, in the conventional apparatus described above, when adjusting the optical axis between the light transmitting axis and the light receiving axis, it is necessary to access a precise measuring device such as an autocollimator. There is a problem in that the laser radar must be separately removed from the mounted device, and the adjustment takes time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional technology, and has as its object to provide a laser radar capable of adjusting an optical axis without using a measuring device. And

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a light transmitting optical system for emitting laser light, and receives reflected light emitted from the light transmitting optical system and reflected on an object. A light-receiving optical system, and a signal processing unit that controls laser light emitted from the light-sending optical system, controls the light-receiving optical system, and performs processing on light received by the light-receiving optical system, A laser radar that automatically adjusts an optical axis of the light receiving optical system based on a light receiving level of light received by the light receiving optical system, wherein the light receiving optical system is an optical deflection optical system that deflects the reflected light, A slit section having a slit having a predetermined width and scanning the light deflected by the optical deflecting optical system, and a detecting section for detecting a light receiving level of light received through the slit section When A, the signal processing unit controls the scanning operation in the slit portion, wherein the controlling the deflection amount in the optical deflecting optical system on the basis of the received light level detected in the detection portion.

The signal processing unit stores the light receiving level input from the detecting unit as data each time a scanning operation is performed in the slit unit, and compares the stored data after the scanning operation. The deflection amount in the optical deflection optical system is controlled.

The slit section has a shutter for forming a slit having a predetermined width, and a motor for driving the shutter, and performs a scanning operation by changing the position of the slit by the shutter. It is characterized by the following.

The optical deflecting optical system has two wedge prisms for deflecting the reflected light, and a motor for rotating the wedge prisms. Is changed.

(Operation) In the present invention configured as described above, when the reflected light of the laser light emitted from the light transmitting optical system is received by the light receiving optical system, the reflected light is received by the optical axis deflection optical system. The emitted light is deflected by a predetermined amount and output. In this state, the position of the slit is sequentially changed in the slit portion, and the light receiving level when the slit is set at each position is detected by the detector,
The detected light receiving level is sent to the signal processing unit and stored as data. Thereafter, in the signal processing unit, the determined one of the stored data is compared with each other to determine the symmetry of the received light level with respect to the movement of the position of the slit, and the optical axis is maintained until the symmetry is satisfied. The same measurement is performed by sequentially changing the deflection amount in the deflection optical system.

As described above, the amount of deflection in the optical axis deflecting optical system is automatically adjusted until the symmetry of the light receiving level with respect to the movement of the slit position is satisfied, that is, until the optical axis in the light receiving optical system is adjusted. Since they can be sequentially changed, the optical axis of the light receiving optical system is adjusted without using a measuring device, and the adjustment does not take time and effort.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a laser radar according to the present invention. FIGS. 2A and 2B are views showing the structure of the slit section 4 shown in FIG. 1, wherein FIG. 2A is a sectional view and FIG. 2B is a front view. FIG. 3 is a sectional view showing the configuration of the optical axis deflecting optical system 5 shown in FIG.

In this embodiment, as shown in FIG. 1, a light transmitting optical system 7 comprising a laser 7a for emitting a laser beam, and a laser 7a
A light receiving optical system 1 for receiving reflected light reflected from a target object and a laser beam emitted from a laser 7a, controlling the light receiving optical system 1 and controlling the light received by the light receiving optical system 1. And a signal processing unit 6 for performing processing.
An optical deflecting optical system 5 that deflects reflected light, and a slit section 3 that scans the light deflected by the optical deflecting optical system 5 in the x direction.
And a slit unit 4 for scanning the light deflected by the optical deflecting optical system 5 in the y direction, and a detecting unit 2 for detecting a light receiving level of the light incident through the slit units 3 and 4. Is provided. Further, as shown in FIG. 2, the slit portion 4 is provided with shutters 10 and 11 for forming a slit 4a having a predetermined width, and motors 8 and 9 for driving the shutters 10 and 11, respectively. ,
The slits 3 are provided with the same components as the slits 4, but are configured to be perpendicular to the slits 4. As shown in FIG. 3, a pair of wedge prisms 15 and 16 for deflecting the reflected light are provided in the optical deflecting optical system 5.
And motors 13 and 14 for rotating the wedge prisms 15 and 16 respectively.

The operation of the laser radar configured as described above will be described below.

FIG. 4 is a timing chart for explaining the operation of the laser radar shown in FIG.

First, when a transmission signal is output from the signal processing unit 6 to the light transmission optical system 7, a laser beam based on the transmission signal is emitted from a laser 7a provided in the light transmission optical system 7. .

Thereafter, when the laser light emitted from the laser 7a is reflected by a certain object, the reflected light is received by the light receiving optical system 1.

When the reflected light is received by the light receiving optical system 1, the received light is deflected by the optical deflecting optical system 5 based on the angles of the wedge prisms 15 and 16 and is output.

The light that has passed through the optical deflecting optical system 5 is received by the detector 2 via the slits 3 and 4. Here, the operation of the slits 3 and 4 will be described in detail.

First, a slit (not shown) provided in the slit portion 3 is opened, and a slit 4a provided in the slit portion 4 has a predetermined width and a slit window 12 (FIG. 2). (See Reference).

In this state, when light is received by the detection unit 2, the light reception level is sent to the signal processing unit 6 as first data and stored.

Next, the motors 8 and 9 are driven by the control of the signal processing section 6, whereby the shutters 10 and 11 move, and the position of the slit 4a moves accordingly.

When light is received by the detection unit 2 in this state, the light reception level is sent to the signal processing unit 6 as second data and stored.

As described above, 2n measurements are repeatedly performed until the slit 4a provided in the slit portion 4 is located at the end opposite to the position initially set with respect to the slit window 12. Will be The distance between the shutter 10 and the shutter 11, which is the width of the slit 4a, is controlled to be constant by driving the motors 8 and 9.

Next, the slit 4a provided in the slit portion 4 is opened, and the same measurement as described above for the slit portion 3 is performed.

Thereafter, the stored data is compared in the signal processing unit 6. In the comparison of the data in the signal processing unit 6, the 2n data scanned in each of the slit units 3 and 4 are compared. , 1
The second data is compared with the 2nth data, the 2nd data and the 2n-1st data,..., The nth data and the (n + 1) th data are compared.

FIGS. 5A and 5B are diagrams showing the received light level output from the detector at each measurement point. FIG. 5A shows a case where the symmetry is satisfied, and FIG. 5B shows a case where the symmetry is satisfied. FIG.

When the comparison results are equal as shown in FIG. 5A, it is determined that the symmetry has been satisfied, and the optical axis adjustment ends.

When the comparison results are not equal to each other, as shown in FIG. 5B, the motors 13 and 14 are driven by the control of the signal processing unit 6, and the wedge prisms 15 and 16 are rotated. , Optical axis deflection optical system 5
Is changed, and the above-described measurement is repeatedly performed.

Here, in the wedge prisms 15 and 16, first, only the wedge prism 15 rotates by a predetermined angle, and the above measurement is performed at each angle. If the symmetry shown in FIG. 5 is not satisfied even after the wedge prism 15 rotates 360 °, the wedge prism 16 rotates by a predetermined angle, and in this state, the wedge prism 15 rotates by a predetermined angle to perform measurement. Will be

In this manner, the wedge prisms 15 and 16 are rotated and measurement is performed until the symmetry shown in FIG. 5 is satisfied.

After the above measurement is repeatedly performed and the symmetry shown in FIG. 5 is satisfied, that is, after the optical axis adjustment is completed, the openings are provided in the slit portions 3 and 4 so that the openings are not closed. The slit is opened.

In the present embodiment configured as described above, the output of the detection unit is monitored using two sets of slits, and a deviation from the center of the detection surface of the detection unit is detected based on the symmetry. can do. In particular, when the spread angle on the light-transmitting side is close to the viewing angle on the light-receiving side, the optical axis can be accurately adjusted.

(Other Embodiments) In the above-described embodiment, the scanning in the x direction using the slit portion 3 is performed.
Although the scanning in the y direction using the slit portion 4 is performed separately, both can be performed simultaneously.

In this case, a rectangular hole is formed by the slit provided in the slit 3 and the slit provided in the slit 4, and scanning is performed using the rectangular hole. Since a two-dimensional distribution is obtained in the output from the detection unit, the optical axis can be adjusted with high accuracy in a short time.

The setting of the slit interval can also serve as an iris for narrowing the field of view.

[0037]

As described above, in the present invention,
Until the symmetry of the light receiving level with respect to the movement of the position of the slit is satisfied, that is, until the optical axis in the light receiving optical system is adjusted, the deflection amount in the optical axis deflection optical system is automatically and sequentially changed. The optical axis of the light receiving optical system can be adjusted without using a measuring device, so that the optical axis adjustment can be performed without trouble.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a laser radar according to the present invention.

FIG. 2 is a view showing a structure of a slit portion shown in FIG. 1,
(A) is a sectional view, and (b) is a front view.

FIG. 3 is a sectional view showing a configuration of an optical axis deflecting optical system shown in FIG. 1;

FIG. 4 is a timing chart for explaining the operation of the laser radar shown in FIG.

5A and 5B are diagrams illustrating light receiving levels output from a detector for each measurement point, where FIG. 5A is a diagram when symmetry is satisfied, and FIG. 5B is a diagram when symmetry is not satisfied. FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light receiving optical system 2 detection unit 3, 4 slit unit 4 a slit 5 optical axis deflection optical system 6 signal processing unit 7 light transmission optical system 7 a laser 8, 9, 13, 14 motor 10, 11 shutter 12 slit window 15, 16 Wedge prism

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01S 7/48-7/51 G01S 17/00-17/95 G01S 11/00

Claims (4)

(57) [Claims] A light transmitting optical system that emits a laser beam; a light receiving optical system that receives light reflected from a target object that is emitted from the light transmitting optical system; and a laser that is emitted from the light transmitting optical system. And a signal processing unit that controls light, controls the light receiving optical system, and performs processing on the light received by the light receiving optical system, based on a light receiving level of the light received by the light receiving optical system. A laser radar for automatically adjusting an optical axis of a light receiving optical system, wherein the light receiving optical system has an optical deflecting optical system for deflecting the reflected light, and a slit having a predetermined width. A slit section that scans the light deflected in the optical system; and a detection section that detects a light receiving level of light received through the slit section. The signal processing section includes: You That controls the scanning operation, the laser radar and controlling the amount of deflection of the optical deflector optical system based on the light reception level detected in the detection portion. 2. The laser radar according to claim 1, wherein the signal processing unit stores a light receiving level input from the detection unit as data each time a scanning operation is performed in the slit unit, and after the scanning operation is completed, A laser radar, wherein the amount of deflection in the optical deflection optical system is controlled by comparing stored data. 3. The laser radar according to claim 2, wherein the slit portion has a shutter that forms a slit having a predetermined width, and a motor that drives the shutter, and the position of the slit is determined by the shutter. A laser radar which performs a scanning operation by changing the value of. 4. The laser radar according to claim 3, wherein the optical deflecting optical system includes two wedge prisms for deflecting the reflected light, and a motor for rotating the wedge prism. A laser radar, wherein the amount of deflection changes as a wedge prism rotates.