Laser radar optical system with optical axis calibrating function and optical axis calibrating method

A laser radar and optical system technology, applied in radio wave measurement systems, instruments, etc., can solve the problems of complex operation and external auxiliary devices, and achieve the effects of simple operation, high optical axis calibration accuracy, and convenient use.

Inactive Publication Date: 2012-02-15

INST OF APPLIED ELECTRONICS CHINA ACAD OF ENG PHYSICS +1

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AI-Extracted Technical Summary

Problems solved by technology

[0003] In order to overcome the deficiencies in the prior art that laser radar optical system optical axis calibration needs an external auxiliary device and complicated operation, the purpose of the present invention is to prov...

Abstract

The invention discloses a laser radar optical system with an optical axis calibrating function and an optical axis calibrating method thereof. A laser emission mirror in the optical system is arranged on an adjusting mechanism which has a pitch angle and an azimuth angle being adjustable accurately and is locked; a retroreflection mirror group is arranged on the outer sides of the laser emission mirror and a signal receiving optical part; and a lighting source is arranged on the outer side between a field diaphragm and a relay lens group. The central position of the field diaphragm representing a laser signal receiving optical axis and the laser far-field spot position representing a laser emission optical axis are successively imaged into a CCD (charge coupled device) camera for detecting a target picture through utilizing a retroreflection characteristic of a pyramid prism in the retroreflection mirror group. The laser emission mirror is adjusted, so that the two positions are coincided in the CCD camera to complete optical axis calibration. The calibrating method disclosed by the invention has high accuracy, is simple to operate, does not rely on an external auxiliary assembly,and is convenient to use.

Application Domain

Wave based measurement systems

Technology Topic

Ccd cameraRelay lens +10

Image

Examples

Experimental program(3)

Example Embodiment

[0025] Example 1

[0026] figure 1 It is a schematic structural diagram of the laser radar optical system with optical axis calibration function of the present invention.

[0027] figure 2 It is a schematic diagram of the structure of the retro-reflecting mirror group in the laser radar optical system with the optical axis calibration function of the present invention.

[0028] image 3 It is a schematic structural diagram of the laser attenuator in the laser radar optical system with the optical axis calibration function of the present invention.

[0029] Figure 4 It is a schematic structural diagram of the illumination light source in the laser radar optical system with the optical axis calibration function of the present invention.

[0030] exist Figures 1~4 Among them, the laser radar optical system with optical axis calibration function of the present invention includes a laser 1, a laser emitting mirror 2, a signal receiving optical element 3, a beam splitter 4, a CCD camera 5, a field diaphragm 6, a relay lens group 7, The photodetector 8, the retroreflector group 9, the illumination light source 10, the adjustment mechanism 20, and the laser emitting mirror 2 are installed on the adjustment mechanism 20 whose pitch angle and azimuth angle can be adjusted and locked. In the retro-reflecting mirror group 9, an illumination light source 10 is arranged on the outside of the optical path between the field diaphragm 6 and the relay lens group 7, and the retro-reflecting mirror group 9 and the illumination light source 10 are respectively arranged on the moving mechanism for optical axis calibration. When the calibration is completed, it moves into the optical path, and after the calibration is completed, it moves out of the optical path.

[0031] The retro-reflecting mirror group 9 includes a first corner cube prism 11, a second corner cube prism 12 and a laser attenuator 13; wherein the laser attenuator 13 is on the side of the light-transmitting surface of the second cube corner prism 12, and is opposite to the second corner cube 12. The cube corner prisms 12 are coaxially arranged; the first cube corner prisms 11 and the second cube corner prisms 12 are arranged side by side. When the retroreflector group 9 moves into the optical path, the first corner cube 11 is aligned with the signal receiving area of the signal receiving optical element 3, and the second cube corner 12 and the laser attenuator 13 are aligned with the laser emitting mirror 2 and the signal Between the signal receiving areas of the receiving optics 3 , that is, the light passing surfaces of the second cube corner prism 12 and the laser attenuator 13 are half aligned with the laser emitting mirror 2 and half aligned with the signal receiving area of the signal receiving optics 3 .

[0032] The laser attenuator 13 includes an attenuation sheet 14 and a light absorption plate 15. The attenuation sheet 14 is arranged at an angle of 45° to the incident optical axis, and the light absorption plate is arranged parallel to the incident optical axis, so that the laser reflected by the attenuation sheet is irradiated on the light absorption plate 15 and absorbed. ; The light-absorbing plate 15 is made of copper, and the surface is oxidized and blackened.

[0033] The illumination light source 10 includes a bulb 16 , a lens 17 , a filter 18 , and a shading tube 19 , wherein the bulb 16 , the lens 17 and the filter 18 are coaxially arranged in sequence and installed in the shading tube 19 . When the illumination light source 10 moves into the light path, its light emission direction is aligned with the field diaphragm 6; the illumination light source 10 has a switch that can control the light emission.

[0034] Figure 5 It is a schematic structural diagram of the optical axis calibration of the laser radar optical system with the optical axis calibration function of the present invention. The steps of the optical axis calibration method of the present invention are as follows:

[0035] a) Move the retroreflector group 9 and the illumination light source 10 into the optical path of the lidar optical system, the illumination direction of the illumination light source 10 is aligned with the center of the field diaphragm 6, and the first corner prism 11 is aligned with the signal receiving optics In the signal receiving area of 3, the light passing surfaces of the second cube corner prism 12 and the laser attenuator 13 are half aligned with the laser emitting mirror 2, and half aligned with the signal receiving area of the signal receiving optics 3;

[0036]b) Turn on the illumination light source 10 to illuminate the field diaphragm 6 . The illumination light is reflected by the first corner prism 11 in the retroreflector group 9 back to the signal receiving optical element 3, and is partially reflected by the beam splitter 4 into the CCD camera 5 for imaging to obtain the image of the field diaphragm 6, and record the CCD The image center position of the field diaphragm 6 in the camera 5 and the image center position of the field diaphragm 6 in the CCD camera 5 represent the position of the receiving optical axis of the laser signal. The illumination light source 10 is turned off.

[0037] c) Turn on the laser 1 to emit laser light. After part of the laser light is reflected by the laser attenuator 13 and the second cube corner prism 12, the reflected light is parallel to the emission optical axis but the transmission direction is opposite. After being transmitted by the signal receiving optics 3, part of the laser light is split The mirror 4 is reflected into the CCD camera 5, and a laser spot image representing the laser emission optical axis is obtained in the CCD camera 5.

[0038] d) Adjust the laser emitting mirror 2 until the laser spot image coincides with the center of the image of the field diaphragm 6 in the CCD camera 5;

[0039] e) Lock the laser emitting mirror 2, move the retroreflector group 9 and the illumination light source 10 out of the optical path, and the optical axis calibration is completed.

[0040] The moving mechanism described in this embodiment is a platform that can move objects.

Example Embodiment

[0041] Example 2

[0042] The basic structure of this embodiment is the same as that of Embodiment 1, except that the light absorption plate 15 set in the laser attenuator 13 is made of graphite material.

Example Embodiment

[0043] Example 3

[0044] The basic structure of this embodiment is the same as that of Embodiment 1, the difference is that the light absorption plate 15 set in the laser attenuator 13 is made of ceramic material.

PUM

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