CN110568420A - A laser radar transceiver alignment device and method - Google Patents

Abstract

The invention relates to a laser radar transceiver alignment device and method, which belongs to the technical field of laser remote sensing and can be used for alignment of the laser radar system transceiver optical axis. The device and method construct a set of independent transmitter-receiver mismatch measurement system through focal plane indicating light, independent area array camera and light-guiding prism and corresponding algorithms, through which the transmitter-receiver mismatch can be obtained in real time and guide the laser The pointing adjustment unit completes the laser radar system transceiver alignment.

Description

A laser radar transceiver alignment device and method

technical field

The invention relates to a laser radar transceiver alignment device and method, which belongs to the technical field of laser remote sensing and can be used for alignment of the laser radar system transceiver optical axis.

Background technique

Lidar can be used for distance detection and atmospheric detection, and is a widely used laser application technology.

Lidar usually uses laser emission with a very small divergence angle and a very narrow field of view to receive, so the alignment of the optical axis of the laser emission and the receiving optical axis is a key factor affecting the performance of the lidar.

In practical applications, a larger receiving field of view can be used to ensure that signals can be received even if the optical axis of the receiving and receiving is deviated, but a larger receiving field of view will introduce larger background light noise.

The use of a small receiving field of view can effectively suppress the interference of background light noise, but due to the influence of structural stability, the alignment of the receiving and receiving optical axes will deteriorate, which will reduce the receiving efficiency and even make the system invalid.

To this end, people have designed an automatic alignment device for lidar. The current automatic alignment device usually installs an area array imaging device such as CCD or CMOS at the rear end of the receiving optical system, and images the echo light or the common optical path indicator light on the above-mentioned area array device by splitting or switching optical paths. The amount of mismatch is judged by the alignment relationship between the spot image on the area array device and the receiving field of view, and the laser emission axis or the optical axis of the receiving field of view is adjusted to complete the transceiver matching.

The above methods usually need to lose part of the echo light or introduce a high-repeatability switching mechanism, and often need to work time-sharing with the lidar system. The main disadvantages are: (1) loss of part of the echo signal; (2) introduction of a switching mechanism with high repeatability requirements; (3) poor real-time performance.

Contents of the invention

The technical problem of the present invention is: to overcome the deficiencies of the prior art, to propose a laser radar transceiver alignment device and method, the device and method through the focal plane indicator light, an independent area array camera and light guide prism and cooperate with the corresponding The algorithm builds a set of independent transceiver mismatch measurement system, through which the transceiver mismatch can be obtained in real time, and guide the laser pointing adjustment unit to complete the laser radar system transceiver alignment.

Technical solution of the present invention is:

A laser radar transceiver alignment device, the laser radar includes a laser emitting unit, a receiving telescope and an echo detection unit;

The transceiving and aligning device includes a transmitting optical axis light guide prism, an optical axis monitoring camera, a receiving optical axis light guiding prism, a first focal plane indicating light source and a second focal plane indicating light source;

The first focal plane indicating light source and the second focal plane indicating light source are located at different positions of the receiving focal plane of the receiving telescope, and the center of the first focal plane indicating light source, the center of the second focal plane indicating light source and the center of the echo detection unit are in common Wire;

The emitting optical axis light guide prism is used to intercept the laser emitted by the laser emitting unit, and transmit the intercepted laser to the optical axis monitoring camera;

The first focal plane indicating light source is used to emit light beams to the receiving telescope, and after receiving the light beams, the receiving telescope collimates the received light beams into first quasi-parallel light and emits them to the outside;

The second focal plane indicates that the light source is used to emit the beam to the receiving telescope, and the receiving telescope collimates the received beam into the second quasi-parallel light after receiving the beam and emits it to the outside;

The receiving optical axis light guide prism is used to intercept the first quasi-parallel light and the second quasi-parallel light emitted by the receiving telescope, and transmit the intercepted first quasi-parallel light and the second quasi-parallel light to the optical axis monitoring camera;

The optical axis monitoring camera is used to receive the laser light transmitted by the optical axis light guide prism, and is also used to receive the intercepted first quasi-parallel light and the second quasi-parallel light transmitted by the optical axis light guide prism, and will receive the The laser beam forms a spot B on the focal plane of the optical axis monitoring camera, forms a spot A on the focal plane of the received intercepted first quasi-parallel light, and receives the intercepted second quasi-parallel light on the focal plane of the optical axis monitoring camera. The parallel light forms a light spot C on the focal plane of the optical axis monitoring camera.

A laser radar transceiver alignment method, the steps of the method comprising:

(1) The laser emitting unit in the laser radar emits laser light to the optical axis light guide prism, and the emission optical axis light guide prism intercepts part of the laser light, and transmits the intercepted part of the laser light to the optical axis monitoring camera;

(2) The first focal plane indicates that the light source emits the first beam to the receiving telescope, the second focal plane indicates that the light source transmits the second beam to the receiving telescope, and the receiving telescope receives the first beam and the second beam and collimates them into the first quasi-parallel The light and the second quasi-parallel light are sent to the receiving optical axis light guide prism, and the receiving optical axis light guide prism intercepts part of the first quasi-parallel light and the second quasi-parallel light, and the intercepted part of the first quasi-parallel light and the second quasi-parallel light Quasi-parallel light is transmitted to the optical axis monitoring camera;

(3) The optical axis monitoring camera forms a light spot B on the focal plane of the optical axis monitoring camera with the received laser light, and forms a light spot A on the focal plane of the optical axis monitoring camera with the first quasi-parallel light received. The received second quasi-parallel light forms a light spot C on the focal plane of the optical axis monitoring camera;

(4) Adjust the direction of the laser emitted by the laser emitting unit to change the position of b' until two conditions are met: the first is that a', b' and c' are collinear; the second is to satisfy the following formula;

Among them, a' is the center position of spot A; b' is the center position of spot B, c' is the center position of spot C, a'-b' is the distance between the center position of spot A and the center position of spot B, c '-b' is the distance between the center position of spot C and the center position of spot B;

b is the center position of the echo detection unit, a is the center position of the first focal plane indicating the light source, c is the center position of the second focal plane indicating the light source, a-b is the center position of the first focal plane indicating the light source and the echo detection unit c-b is the distance between the center position of the second focal plane indicating the light source and the center position of the echo detection unit;

At this point, the laser radar emission and reception alignment is completed.

Beneficial effect

(1) Using this method can ensure the matching reliability of the laser radar system, especially the large laser radar system.

(2) Compared with the optical-splitting transceiver matching method, this method does not lose the echo signal, effectively preserves the signal-to-noise ratio, and avoids stray light interference caused by optical splitting.

(3) Compared with the transceiver matching method of configuring switching components, this method does not introduce switching components, thus avoiding system failure due to switching function failures.

(4) Compared with the sending and receiving matching method of configuring switching components, using this method can adjust the sending and receiving matching state in real time, and can increase the proportion of working time.

(5) Compared with the method of transmitting and receiving matching based on echo signals, this method does not depend on the quality of echo signals, and can greatly reduce the requirements for the environment and working conditions of transmitting and receiving matching.

(6) Using this method can monitor the matching state of the transmission and reception of the system in real time, and effectively improve the monitoring capability and emergency response capability of mismatch faults.

Description of drawings

Figure 1 is a schematic diagram of the composition of the device of the present invention.

Detailed ways

The laser radar system includes a laser emitting unit 1 of the laser radar, a receiving telescope 5 and a laser radar echo detection unit 7 .

As shown in Figure 1, the laser radar transceiver alignment system is mainly composed of a transmitting optical axis light guide prism 2, an optical axis monitoring camera 3, a receiving optical axis light guiding prism 4, a focal plane indicating light source 6 and a focal plane indicating light source 8.

The lidar automatic alignment method is as follows:

Measuring the coordinate positions a and c of the focal plane indicating light 6 and the focal plane indicating light 8 on the focal plane of the receiving telescope 5;

Measuring the coordinate position b of the echo detection unit 7 on the focal plane of the receiving telescope 5;

The laser emitting unit 1 of the lidar emits laser light;

The emitting optical axis light guide prism 2 intercepts a small amount of laser light emitted by the laser emitting unit 1, and transmits it to the optical axis monitoring camera 3;

The focal plane indicating light source 6 and the focal plane indicating light source 8 emit light, and enter the receiving optical axis light guide prism 4 after passing through the receiving telescope 5;

The receiving optical axis light guide prism intercepts a small amount of quasi-parallel light collimated by the focal plane indicator light source 6 and the focal plane indicator light source 8 through the receiving telescope 5, and transmits it to the optical axis monitoring camera 3;

The area array camera 3 images the light incident from the emitting optical axis light guide prism 2 and the receiving optical axis light guide prism 4, wherein the image points representing the focal plane indicator light source 6 and the focal plane indicator light source 8 are respectively a' and c', The image point representing the optical axis of the laser emitting unit is b'.

According to the optical principle, when the laser emitting optical axis is aligned with the receiving optical axis limited by the echo detection unit, the image point b' on the focal plane of the optical axis monitoring camera should pass through the receiving telescope 5 and the receiving light of the laser radar echo unit 7 The axial light guide prism 4 coincides with the imaging point of the optical path imaging of the area array camera.

Change the position of b' by adjusting the direction of the laser beam emitted by the laser emitting unit until the following conditions are met:

At this point, the laser radar system launch and receive alignment can be completed.

Example

As shown in Figure 1, a laser radar transceiver alignment device, the laser radar includes a laser emitting unit 1, a receiving telescope 5 and an echo detection unit 7;

Wherein, the laser emitting unit emits pulsed laser light with a wavelength of 1064nm. The focal length of the receiving telescope is 1m.

The transceiver alignment device includes a transmitting optical axis light guide prism 2, an optical axis monitoring camera 3, a receiving optical axis light guiding prism 4, a first focal plane indicating light source 6 and a second focal plane indicating light source 8;

The focal length of the optical axis monitoring camera 3 is 0.25m, the first focal plane indicates that the light source 6 emits a 1064nm continuous laser, and the second focal plane indicates that the light source 8 emits a 1064nm continuous laser.

The first focal plane indicating light source 6 and the second focal plane indicating light source 8 are located at different positions of the receiving focal plane of the receiving telescope 5, and the center of the first focal plane indicating light source 6, the center of the second focal plane indicating light source 8 and the echo The centers of the detection units 7 are collinear;

Let the center a coordinate of the first focal plane indicating light source 6 be 0 mm, the center c coordinate of the second focal plane indicating light source 8 be 4 mm, and the center b coordinate of the echo detection unit 7 be 2 mm.

The emitting optical axis light guide prism 2 is used to intercept the laser emitted by the laser emitting unit 1, and transmit the intercepted laser to the optical axis monitoring camera 3;

The first focal plane indicating light source 6 is used to emit light beams to the receiving telescope 5, and the receiving telescope 5 collimates the received light beams into the first quasi-parallel light after receiving the light beams and emits them to the outside;

The second focal plane indicating light source 8 is used to emit light beams to the receiving telescope 5, and the receiving telescope 5 collimates the received light beams into second quasi-parallel light after receiving the light beams and emits them to the outside;

The receiving optical axis light guide prism 4 is used to intercept the first quasi-parallel light and the second quasi-parallel light emitted by the receiving telescope 5, and transmit the intercepted first quasi-parallel light and the second quasi-parallel light to the optical axis monitoring camera 3;

The optical axis monitoring camera 3 is used to receive the laser light transmitted by the optical axis light guide prism 2, and is also used to receive the intercepted first quasi-parallel light and the second quasi-parallel light transmitted by the receiving optical axis light guide prism 4, and The received laser light forms a light spot B on the focal plane of the optical axis monitoring camera 3, and the received intercepted first quasi-parallel light forms a light spot A on the focal plane of the optical axis monitoring camera 3, and the received The intercepted second quasi-parallel light forms a light spot C on the focal plane of the optical axis monitoring camera 3 .

Let the coordinate a' of the center of spot A be 0 mm, and the coordinate c' of the center of spot C be 1 mm.

A laser radar transceiver alignment method, the steps of the method comprising:

(1) In the laser radar, the laser emitting unit 1 emits laser light to the emission optical axis light guide prism 2, and the emission optical axis light guide prism 2 intercepts part of the laser light, and transmits the intercepted part of the laser light to the optical axis monitoring camera 3;

(2) The first focal plane indicating light source 6 emits the first beam to the receiving telescope 5, the second focal plane indicating light source 8 emits the second beam to the receiving telescope 5, and the receiving telescope 5 collimates after receiving the first beam and the second beam The first quasi-parallel light and the second quasi-parallel light are sent to the receiving optical axis light guide prism 4, and the receiving optical axis light guide prism 4 intercepts part of the first quasi-parallel light and the second quasi-parallel light, and the intercepted part The first quasi-parallel light and the second quasi-parallel light are transmitted to the optical axis monitoring camera 3;

(3) The optical axis monitoring camera 3 forms a light spot B on the focal plane of the optical axis monitoring camera 3 with the received laser light, and forms a light spot on the focal plane of the optical axis monitoring camera 3 with the first quasi-parallel light received A, forming a spot C of the received second quasi-parallel light on the focal plane of the optical axis monitoring camera 3;

(4) Use double wedges to adjust the direction of the laser light emitted by the laser emitting unit 1 to change the position of b' until two conditions are met: first, a', b' and c' are collinear; second, b' = 0.5 mm.

Among them, a' is the center position of spot A; b' is the center position of spot B, c' is the center position of spot C, a'-b' is the distance between the center position of spot A and the center position of spot B, c '-b' is the distance between the center position of spot C and the center position of spot B;

b is the center position of the echo detection unit 7, a is the center position of the first focal plane indicating the light source 6, c is the center position of the second focal plane indicating the light source 8, a-b is the center position of the first focal plane indicating the light source 6 and The distance between the central position of the echo detection unit 7, c-b is the distance between the central position of the second focal plane indicating light source 8 and the central position of the echo detection unit 7;

At this point, the laser radar emission and reception alignment is completed.

Claims (10)

1. A laser radar receives and dispatches aligning device which characterized in that: the laser radar comprises a laser transmitting unit, a receiving telescope and an echo detecting unit;

The transmitting-receiving alignment device comprises a transmitting optical axis light guide prism, an optical axis monitoring camera, a receiving optical axis light guide prism, a first focal plane indicating light source and a second focal plane indicating light source;

the first focal plane indicating light source and the second focal plane indicating light source are positioned at different positions of a receiving focal plane of the receiving telescope, and the center of the first focal plane indicating light source, the center of the second focal plane indicating light source and the center of the echo detection unit are collinear;

The emission optical axis light guide prism is used for intercepting laser emitted by the laser emission unit and transmitting the intercepted laser to the optical axis monitoring camera;

the first focal plane indicating light source is used for emitting light beams to the receiving telescope, and the receiving telescope collimates the received light beams into first quasi-parallel light and then emits the first quasi-parallel light to the outside after receiving the light beams;

The second focal plane indicating light source is used for emitting light beams to the receiving telescope, and the receiving telescope collimates the received light beams into second quasi-parallel light and then emits the second quasi-parallel light to the outside after receiving the light beams;

the receiving optical axis light guide prism is used for intercepting the first quasi-parallel light and the second quasi-parallel light transmitted by the receiving telescope and transmitting the intercepted first quasi-parallel light and second quasi-parallel light to the optical axis monitoring camera;

The optical axis monitoring camera is used for receiving laser transmitted by the transmitting optical axis light guide prism and also used for receiving intercepted first quasi-parallel light and second quasi-parallel light transmitted by the receiving optical axis light guide prism, the received laser forms a light spot B on a focal plane of the optical axis monitoring camera, the received intercepted first quasi-parallel light forms a light spot A on the focal plane of the optical axis monitoring camera, and the received intercepted second quasi-parallel light forms a light spot C on the focal plane of the optical axis monitoring camera.

2. A laser radar transmit-receive alignment method is characterized by comprising the following steps:

(1) a laser transmitting unit in the laser radar transmits laser to a transmitting optical axis light guide prism, the transmitting optical axis light guide prism intercepts part of the laser and transmits the intercepted part of the laser to an optical axis monitoring camera;

(2) the first focal plane indicating light source transmits a first light beam to the receiving telescope, the second focal plane indicating light source transmits a second light beam to the receiving telescope, the receiving telescope receives the first light beam and the second light beam, collimates the first quasi-parallel light and the second quasi-parallel light and transmits the first quasi-parallel light and the second quasi-parallel light to the receiving optical axis light guide prism, the receiving optical axis light guide prism intercepts part of the first quasi-parallel light and the second quasi-parallel light and transmits the intercepted part of the first quasi-parallel light and the second quasi-parallel light to the optical axis monitoring camera;

(3) The optical axis monitoring camera forms a light spot B on the focal plane of the optical axis monitoring camera by the received laser, forms a light spot A on the focal plane of the optical axis monitoring camera by the received first quasi-parallel light, and forms a light spot C on the focal plane of the optical axis monitoring camera by the received second quasi-parallel light;

(4) Adjusting the direction of the laser emitted by the laser emitting unit until the following conditions are met, and finishing the alignment of the laser radar emission and the laser radar receiving;

3. The lidar transceiver alignment method according to claim 2, wherein: in the step (4), a' is the central position of the light spot A; b 'is the center position of spot B and C' is the center position of spot C.

4. The lidar transceiver alignment method according to claim 2 or 3, wherein: in the step (4), a '-B' is a distance between the center position of the spot a and the center position of the spot B.

5. the lidar transceiver alignment method according to claim 4, wherein: in the step (4), C '-B' is a distance between the center position of the spot C and the center position of the spot B.

6. the lidar transceiver alignment method according to claim 4, wherein: in the step (4), b is the central position of the echo detection unit.

7. the lidar transceiver alignment method according to claim 5 or 6, wherein: in the step (4), a indicates the central position of the light source for the first focal plane.

8. the lidar transceiver alignment method according to claim 7, wherein: in the step (4), c indicates the central position of the light source for the second focal plane.

9. the lidar transceiver alignment method according to claim 7, wherein: in the step (4), a-b are distances between the central position of the first focal plane indicating light source and the central position of the echo detection unit.

10. The lidar transceiver alignment method according to claim 8 or 9, wherein: in the step (4), c-b is the distance between the central position of the second focal plane indicating light source and the central position of the echo detection unit.