A kind of invisible light laser radar transceiver light path fast coaxial calibration device

Abstract

The application provides a kind of invisible light laser radar transmitting and receiving light path fast coaxial calibration device, and relates to the technical field of laser radar.The invisible light laser radar transmitting and receiving light path fast coaxial calibration device includes a receiving telescope, and the receiving telescope is provided with a telescope receiving surface.The application can quickly and real-time locate and display the reference light spot position and exit direction by introducing a visible light calibration light source, which can quickly and conveniently assist in debugging and calibrating the coaxiality of the non-visible light laser radar transmitting and receiving light path, solve the problems of spending a lot of time for blind calibration in the existing non-visible light source laser radar system, and being unable to determine whether the light beam interferes with the light path turning system structure, resulting in light spot loss and misalignment, improve the debugging efficiency of the operator, and ensure the environmental safety of the operator in the case of high-power invisible laser light source, with low cost, simple and flexible calibration method, and can be used as a tool structure to assist in field debugging.

Description

Technical Field

[0001] This invention relates to the field of lidar technology, specifically to a rapid coaxial calibration device for the light receiving and transmitting paths of an invisible light lidar. Background Technology

[0002] With the rapid development of lidar technology both domestically and internationally, it has become a powerful detection tool in fields such as atmosphere, meteorology, environment, space, remote sensing, and military. Lidar is an active detection technology that utilizes lasers. It processes and inverts the echo signals generated during the interaction between the laser and the atmosphere to obtain the distribution characteristics of multiple atmospheric parameters, such as extinction coefficient, depolarization ratio, and particulate matter concentration distribution. Although the echo signal is directly determined by the real-time distribution of atmospheric composition, aerosols, and clouds along the inversion path, the measurement accuracy of the lidar system also has a significant impact on the echo signal. Therefore, calibration and debugging of the lidar system are crucial. As the range of atmospheric components and types detected continues to expand, the wavelength range of laser sources in atmospheric lidar detection systems is gradually extending beyond visible light to the ultraviolet or near-infrared bands. For such invisible laser source lidar systems, rapid and efficient system calibration to ensure the coaxiality of the light source and receiving system is critical for high-precision lidar inversion detection. Simultaneously, ensuring the safety of debugging and operation personnel under invisible light conditions is of great significance.

[0003] The current conventional method for coaxial calibration of non-visible light lidar is to blindly adjust the signal until it meets the four-quadrant calibration accuracy range. During the operation, the position or directionality of the light spot is observed at close range using a photosensitive film of the corresponding wavelength for calibration. This method is cumbersome and not intuitive. In addition, the strong scattered light energy in the near field during the frequent use of the photosensitive film in the coaxial system can damage the detector performance.

[0004] Another method involves frequency doubling of non-visible light wavelengths to convert them into visible light for optical path directivity adjustment. This method has high accuracy in calibrating the angle of the frequency doubling crystal, but the light source energy needs to be excited to a certain energy density before conversion can be performed. The adjustment process is complex and costly. Due to crystal cutting angle, placement position, and non-critical phase matching errors, there is a certain angular difference in the coaxiality between non-visible light and excited visible light, which affects the adjustment efficiency and accuracy. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a rapid coaxial calibration device for the light-receiving and receiving paths of invisible light lidar. This device solves the problems of cumbersome operation in existing calibration methods and the damage to detector performance caused by strong scattered light energy in the near field during frequent use of the photosensitive film.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution: a fast coaxial calibration device for the receiving and transmitting optical paths of an invisible light lidar, comprising a receiving telescope, the receiving telescope having a receiving surface, a first optical path deflecting mirror being disposed on one side of the receiving surface, a corner cube prism being disposed on the side of the first optical path deflecting mirror away from the receiving telescope, and a light source device being disposed above the first optical path deflecting mirror, the light source device including a visible light source device and a non-visible light source device;

[0009] The visible light source device includes a visible light source emitter. A beam shaper is connected to the emitting end of the visible light source emitter. The beam shaper mainly shapes and restricts the beam size, collimation, and divergence angle of the visible light source to match the beam characteristics of the invisible light laser. For example, for LEDs, which have large beam divergence angles and large beam spots, a pinhole aperture and a single lens can be used to cut and shape the beam, so that the beam size and divergence characteristics after shaping match the beam performance parameters of the invisible light laser to be coupled, thereby achieving the purpose of beam combining. Alternatively, emitters such as LDs, small fiber lasers, and helium-neon lasers with beam spot size and divergence angles consistent with the parameters of the invisible light source to be calibrated can be selected, which can reduce the input of this process. A beam directivity adjuster is set at the beam shaper position. The beam directivity adjuster is mainly a device to control the directivity of the calibration light source (visible light source) and the test light source (invisible light laser) to be consistent, so that the light source is coaxial and concentric with the laser source in the system. The adjustment system can be an optical wedge or an adjustable reflector group.

[0010] Preferably, the non-visible light source device includes an invisible light laser, the emitting end of the invisible light laser is connected to a beam expander, and the emitting end of the beam expander is provided with a second optical path deflector.

[0011] Preferably, a beam coupling system is provided below the second optical path deflector. The beam coupling system is mainly a device for coupling and combining visible light source and invisible light laser source. The coupling device can be a dichroic mirror, which has the performance characteristics of high transmittance of invisible laser wavelength and high reflectivity of visible light wavelength, or a suitable beam splitter is selected and used according to the type of light source. The beam coupling system is directly opposite the beam directivity adjuster.

[0012] Preferably, a laser colorimetric card is disposed below the beam coupling system, and the laser colorimetric card, the beam coupling system, the second optical path deflector and the first optical path deflector are located on the same vertical line.

[0013] Preferably, an aperture is provided on the side of the receiving telescope away from the receiving surface of the telescope.

[0014] Preferably, the invisible light laser is a semiconductor solid-state laser, and the wavelength type is invisible light or contains invisible light, which can be in the ultraviolet band or near-infrared band. The beam expander is a beam expanding system built into the invisible light laser, which is a device used to control the spot size, collimation and divergence angle.

[0015] Working principle:

[0016] a. An invisible light is emitted by an invisible laser, and then coaxially emitted into the air through a second optical path deflector and a first optical path deflector with a receiving telescope to form the invisible laser light source to be tested. A visible light source emitter emits a visible calibration light source.

[0017] b. After the beam shaper design, the visible calibration light source emitted by the visible light source emitter is combined with the invisible light laser source under test through the beam coupling system. The directivity of the visible calibration light source beam is adjusted through the beam directivity adjustment system, and then the beam is combined again through the beam coupling system. Finally, the laser color chart is used to ensure that the invisible light laser source under test and the visible calibration light source are coaxial and concentric.

[0018] c. Take out the laser color chart and adjust the first optical path deflector to test the beam directionality of the invisible laser light source and the visible calibration light source. The receiving telescope is a total reflection Cassegrain telescope system. There is no color difference at the convergence point of different wavelengths. You can directly observe whether the imaging spot of the visible calibration light source passes through the pinhole aperture of the receiving telescope through the corner prism.

[0019] d. After calibrating the coaxiality of the beam transmission and reception, remove the visible light source emitter, beam coupling system, and corner cube prism.

[0020] (III) Beneficial Effects

[0021] This invention provides a rapid coaxial calibration device for the receiving and transmitting optical paths of an invisible light lidar system. It offers the following advantages:

[0022] This invention introduces a visible light source to quickly and in real-time locate and display the position and emission direction of the reference spot. It can quickly and conveniently assist in debugging and calibrating the coaxiality of the receiving and transmitting light paths of non-visible light lidar. It solves the problems of existing non-visible light source lidar systems that require a lot of time for blind calibration and cannot determine whether the beam interferes with the optical path turning system structure, resulting in spot loss and misalignment. It improves the debugging efficiency of operators while ensuring the environmental safety of debugging personnel under high-power invisible laser light source conditions. It is low in cost, has a simple and flexible calibration method, and can be used as a tooling structure to assist in field debugging. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a fast coaxial calibration device for the receiving and transmitting optical paths of an invisible light lidar according to the present invention.

[0024] Among them, 1. Visible light source emitter; 2. Beam shaper; 3. Beam expander; 4. Invisible light laser; 5. Beam coupling system; 6. Laser color chart; 7. Aperture; 8. Receiving telescope; 9. Telescope receiving surface; 10. First optical path deflector; 11. Cornerstone prism; 12. Beam directivity adjuster; 13. Second optical path deflector. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1:

[0027] like Figure 1 As shown in the embodiment of the present invention, a fast coaxial calibration device for the receiving and receiving optical paths of an invisible light lidar is provided, including a receiving telescope 8, an aperture 7 is provided on the side of the receiving telescope 8 away from the telescope receiving surface 9, the receiving telescope 8 is provided with the telescope receiving surface 9, a first optical path deflecting mirror 10 is provided on one side of the telescope receiving surface 9, a corner bevel prism 11 is provided on the side of the first optical path deflecting mirror 10 away from the receiving telescope 8, and a light source device is provided above the first optical path deflecting mirror 10, the light source device including a visible light source device and a non-visible light source device;

[0028] The non-visible light source device includes an invisible light laser 4, which is a semiconductor solid-state laser. The beam expander 3 is a beam expanding system integrated with the invisible light laser 4. The beam expander 3 is connected to the emitting end of the invisible light laser 4. A second optical path deflector 13 is provided at the emitting end of the beam expander 3. A beam coupling system 5 is provided below the second optical path deflector 13. A laser color display card 6 is provided below the beam coupling system 5. The laser color display card 6, the beam coupling system 5, the second optical path deflector 13, and the first optical path deflector 10 are located on the same vertical line. The beam coupling system 5 is directly opposite the beam directivity adjuster 12. The visible light source device includes a visible light source emitter 1. A beam shaper 2 is connected to the emitting end of the visible light source emitter 1. A beam directivity adjuster 12 is provided at the position of the beam shaper 2.

[0029] Example 2:

[0030] The specific working method of the coaxial calibration device is as follows:

[0031] a. Invisible light is emitted by the invisible light laser 4, and then coaxially emitted into the air through the second optical path deflector 13 and the first optical path deflector 10 with the receiving telescope 8 to form the light source of the invisible light laser to be tested. The visible light source emitter 1 emits a visible calibration light source.

[0032] b. After the beam shaper 2 is designed, the visible calibration light source emitted by the visible light source emitter 1 is combined with the invisible light laser source under test through the beam coupling system 5. The directivity of the visible calibration light source beam is adjusted by the beam directivity adjustment system 12, and then the beam is combined again through the beam coupling system 5. Finally, the laser color chart 6 is used to ensure that the invisible light laser source under test and the visible calibration light source are coaxial and concentric.

[0033] c. Take out the laser color chart 6 and adjust the first optical path deflector 10 to debug the beam directionality of the invisible laser light source to be tested and the visible calibration light source. The receiving telescope 8 is a total reflection Cassegrain telescope system. There is no color difference at the convergence point of different wavelengths. The imaging spot of the visible calibration light source can be directly observed through the corner prism to see whether it passes through the small aperture 7 of the receiving telescope 8.

[0034] d. After calibrating the coaxiality of the beam transmission and reception, remove the visible light source emitter 1, beam coupling system 5, and corner cube prism 11.

[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rapid coaxial calibration device for the receiving and transmitting optical paths of an invisible light lidar, characterized in that, The system includes a receiving telescope (8), which is a total internal reflection Cassegrain telescope system with no chromatic aberration at the convergence point of different wavelengths. The receiving telescope (8) is provided with a telescope receiving surface (9). A first optical path deflecting mirror (10) is provided on one side of the telescope receiving surface (9). A corner prism (11) is provided on the side of the first optical path deflecting mirror (10) away from the receiving telescope (8). A light source device is provided above the first optical path deflecting mirror (10). The light source device includes a visible light source device and a non-visible light source device. The visible light source device includes a visible light source emitter (1), and a beam shaper (2) is connected to the emitting end of the visible light source emitter (1). The beam shaper (2) is used to shape and constrain the spot size, collimation and divergence angle of the visible light source beam, and is used to match the beam characteristics of the invisible light laser. A beam directivity adjuster (12) is provided at the position of the beam shaper (2). The non-visible light source device includes an invisible light laser (4), the emitting end of the invisible light laser (4) is connected to a beam expander (3), and the emitting end of the beam expander (3) is provided with a second optical path deflector (13). A beam coupling system (5) is provided below the second optical path deflector (13). The beam coupling system (5) faces the beam directivity adjuster (12). The beam coupling system (5) is a dichroic mirror. It has high transmittance for the invisible laser wavelength emitted by the invisible laser (4) and high reflectivity for the visible light wavelength emitted by the visible light source emitter (1). It is used to couple the visible light source and the invisible laser source together. A laser color display card (6) is provided below the beam coupling system (5). The laser color display card (6), the beam coupling system (5), the second optical path deflector (13), and the first optical path deflector (10) are located on the same vertical line. An aperture (7) is provided on the side of the receiving telescope (8) away from the telescope receiving surface (9). After calibrating the coaxial transmission and reception of the beam, the visible light source emitter (1), beam coupling system (5), and corner cube prism (11) can be removed from the lidar system without affecting the normal operation of the lidar.

2. The fast coaxial calibration device for the receiving and transmitting optical paths of an invisible light lidar according to claim 1, characterized in that, The invisible light laser (4) is a semiconductor solid-state laser, and the beam expander (3) is a beam expanding system built into the invisible light laser (4).

3. A rapid coaxial calibration device for the receiving and transmitting optical paths of an invisible light lidar according to claim 1 or 2, characterized in that, The specific working method of the coaxial calibration device is as follows: a. Invisible light is emitted by the invisible light laser (4), and then coaxially emitted into the air with the receiving telescope (8) through the second optical path deflector (13) and the first optical path deflector (10) to form the light source of the invisible light laser to be tested. The visible light source emitter (1) emits a visible calibration light source. b. After the beam shaper (2) is designed, the visible calibration light source emitted by the visible light source emitter (1) is combined with the invisible light laser source under test through the beam coupling system (5). The directivity of the visible calibration light source beam is adjusted by the beam directivity adjuster (12), and the beam is combined again through the beam coupling system (5). Then, the laser color chart (6) is used to ensure that the invisible light laser source under test and the visible calibration light source are coaxial and concentric. c. Take out the laser color card (6) and then adjust the first optical path deflector (10) to adjust the beam directionality of the invisible laser light source to be tested and the visible calibration light source. The receiving telescope (8) is a total reflection Cassegrain telescope system. There is no color difference at the convergence point of different wavelengths. The visible calibration light source imaging spot can be directly observed through the corner prism to see whether it passes through the aperture (7) of the receiving telescope (8). d. After calibrating the coaxiality of the beam transmission and reception, remove the visible light source emitter (1), beam coupling system (5), and corner cube prism (11).

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