CN113030904A - Automatic focusing device and method for laser radar light source - Google Patents
Automatic focusing device and method for laser radar light source Download PDFInfo
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- CN113030904A CN113030904A CN202110275717.7A CN202110275717A CN113030904A CN 113030904 A CN113030904 A CN 113030904A CN 202110275717 A CN202110275717 A CN 202110275717A CN 113030904 A CN113030904 A CN 113030904A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/4804—Auxiliary means for detecting or identifying lidar signals or the like, e.g. laser illuminators
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/497—Means for monitoring or calibrating
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
- G02B7/28—Systems for automatic generation of focusing signals
- G02B7/36—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals
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Abstract
The invention provides an automatic focusing device and method for a laser radar light source, belonging to the field of laser radar production equipment and comprising a support, an adjusting component, an imaging light screen, an image acquisition unit and a control unit; the support is used for connecting a laser radar light source; the adjusting component can be arranged opposite to the laser radar light source and is provided with an adjusting end which can be in butt joint with the lens component and a channel through which a light beam emitted by the laser radar light source can pass; the imaging light screen is arranged on the emergent side of the channel; the image acquisition unit is used for acquiring a light spot image on the imaging light screen in real time and generating image information; the control unit is respectively in communication connection with the image acquisition unit and the adjusting assembly so as to control the action of the adjusting end according to the image information. According to the automatic focusing device and the automatic focusing method for the laser radar light source, manual direct participation is not needed, the automation degree is improved, the time used in the debugging process is shortened, the adjustment consistency can be ensured, and the yield of products is effectively improved.
Description
Technical Field
The invention belongs to the technical field of laser radar production equipment, and particularly relates to an automatic focusing device for a laser radar light source.
Background
The laser radar is a radar system for detecting an object by using a laser beam, obtains information such as the position, distance, speed, contour and the like of the object by emitting the laser beam to a target, detecting and processing a light signal returned by the target object, has the advantages of high detection precision, high detection speed and the like, and is widely applied to the fields of robot drawing, obstacle avoidance and the like.
In recent years, laser radars are widely used in industry and intelligent manufacturing industry, but because optical elements of the laser radars have higher assembly requirements, certain working hours are often needed for assembling and calibrating the optical elements in the laser radar production process, and the assembling precision directly influences the overall performance index of the laser radars. For a light source component, an LD bare chip can obtain a light spot with concentrated energy through lens collimation, when defocusing occurs in the collimation process, the collimated light spot has astigmatism phenomena with different degrees, the astigmatism influences the strength of a received signal to different degrees, more importantly, the light spot is easy to generate invalid optical scattering in equipment, the judgment of the signal is influenced, and the accuracy of a radar is directly influenced.
The existing optical element assembly and adjustment process adopts manual direct adjustment and adjustment, so that the alignment focus is time-consuming to find, the adjustment consistency is difficult to achieve, the production efficiency is influenced, and the product yield is not improved.
Disclosure of Invention
The invention aims to provide an automatic focusing device and method for a laser radar light source, and aims to solve the technical problems of low production efficiency and high product reject ratio of a manual focusing process in the prior art.
In order to achieve the purpose, the invention adopts the technical scheme that: the utility model provides a laser radar light source automatic focusing device for adjust the focus of laser radar light source, the laser radar light source is including the light source mount pad that has the through-hole, locate the laser diode of through-hole one end, and connect in the through-hole other end just can follow the axial displacement's of through-hole lens subassembly, laser radar light source automatic focusing device includes:
the support is used for connecting the laser radar light source;
the adjusting assembly is arranged on the support and can be arranged opposite to the laser radar light source, the adjusting assembly is provided with an adjusting end capable of being in butt joint with the lens assembly and a channel capable of enabling a light beam emitted by the laser radar light source to pass through, and the adjusting end can drive the lens assembly to be close to or far away from the laser diode;
the imaging light screen is arranged on the emergent side of the channel so that the light beams can be projected onto the imaging light screen;
the image acquisition unit is used for acquiring the light spot image on the imaging light screen in real time and generating image information; and
and the control unit is in communication connection with the image acquisition unit and the adjusting assembly respectively so as to control the action of the adjusting end according to the image information.
As another embodiment of the present application, the lens assembly is in threaded fit with the through hole, and the support includes two oppositely disposed bases, wherein one of the bases is used for connecting the lidar light source and making the lens assembly face the other base;
the adjustment assembly includes:
the two ends of each sliding rod are respectively connected to the two seat bodies, and the adjacent sliding rods are parallel to each other;
the rotary driver is provided with an output shaft and a driving main body, the driving main body is connected to the sliding rod in a sliding mode, and the output shaft forms the adjusting end; and
the connecting piece is arranged at the end part of the output shaft and used for being connected with the lens assembly, the channel penetrates through the connecting piece, the output shaft and the driving main body, and the sliding rod is parallel to the channel.
As another embodiment of the present application, the connecting member drives the lens assembly to rotate by an extrusion friction force or an absorption force, the adjusting assembly further includes an elastic member, the elastic member is disposed between the rotary actuator and the other seat body, and the elastic member is configured with a pretightening force for keeping the connecting member pressed against the lens assembly.
As another embodiment of the application, the elastic element is a compression spring, and the compression spring is sleeved on the periphery of the sliding rod.
As another embodiment of this application, laser radar light source automatic focusing device still includes supplementary grip ring to and locate one of them locating pin on the pedestal, the locating pin can run through the light source mount pad with supplementary grip ring, supplementary grip ring can with the pedestal cooperation centre gripping the light source mount pad.
As another embodiment of this application, laser radar light source automatic focusing device still includes the sleeve, the muffjoint is located the periphery of output shaft, and can cover and locate the periphery of lens subassembly.
As another embodiment of the present application, the image capturing unit is an infrared camera.
The automatic focusing device for the laser radar light source provided by the invention has the beneficial effects that: compared with the prior art, the automatic focusing device for the laser radar light source can drive the lens assembly to move through the adjusting assembly, so that the distance between the lens assembly and the laser diode is adjusted (focusing), light beams emitted by the laser diode and formed after passing through the lens assembly can completely pass through the channel to be displayed on the imaging light screen, in the adjusting process, the image acquisition unit can acquire light spot images on the imaging light screen in real time to form image information, the control unit analyzes the image information after acquiring the image information, the accurate adjustment of the lens assembly is controlled through the image information, manual direct participation is not needed, the automation degree is improved, the time used in the debugging process is reduced, the adjustment consistency can be ensured, and the yield of products is effectively improved.
The invention also provides an automatic laser radar light source focusing method, which is realized based on the automatic laser radar light source focusing device and comprises the following steps:
adjusting the distance between the lens component and the laser diode until an initial light spot image is obtained;
performing oscillation type convergence adjustment on the distance between the lens assembly and the laser diode, and acquiring a light spot image in real time;
generating image information in real time according to the light spot image, wherein the image information is an image gray distribution histogram, and acquiring histogram distribution width information and histogram gray maximum value information according to the image gray distribution histogram;
judging whether the distribution width of the histogram changes in a first standard range or not and whether the gray maximum value of the histogram changes in a second standard range or not;
when the distribution width of the histogram changes in a first standard range and the gray maximum value of the histogram changes in a second standard range, the adjustment is judged to be finished;
when the change of the distribution width of the histogram exceeds a first standard range and/or the change of the maximum value of the gray scale of the histogram exceeds a second standard range, the adjustment is continued.
As another embodiment of the present application, the adjusting device further includes adjusting device parameters before adjusting the distance between the lens assembly and the laser diode until the initial spot image is acquired, where the adjusting device parameters specifically include:
adjusting working parameters of the image acquisition unit;
adjusting the size of the channel to make the size of the channel satisfy the relational expression
D≥d+L×tanθ (1)
Wherein D is the inner diameter of the channel, theta is the divergence angle of the slow axis, L is the length of the channel, and D is the light transmission aperture of the lens assembly.
As another embodiment of the present application, the adjusting the distance between the lens assembly and the laser diode until the initial spot image is acquired further includes:
acquiring light spot position information according to the initial light spot image, and acquiring an image region of interest according to the light spot position information;
the interval between lens subassembly and the laser diode vibrates formula convergence adjustment to obtain the facula image in real time, specifically include:
and performing oscillation type convergence adjustment on the distance between the lens assembly and the laser diode, and acquiring a light spot image in the image region of interest in real time.
The laser radar light source automatic focusing method provided by the invention has the beneficial effects that: compared with the prior art, the automatic focusing method of the laser radar light source has the advantages that the aggregation and the divergence of the light spots correspond to the change of the gray value, the energy of the light spots is gradually concentrated in the collimation adjusting process, the size of the light spots in the fast axis direction is obviously reduced, the light energy (namely the light power density) of a unit area is gradually increased, the image gray value is obviously increased when the image gray value is not collimated, the light spot image is obtained in real time by the image acquisition unit, the image is processed to obtain a real-time image gray distribution histogram, and whether the focusing is in place or not can be visually judged by obtaining the histogram distribution width and the maximum histogram gray value in the histogram. The automatic laser radar light source focusing method is simple to operate, high in response speed and capable of being achieved through automation of equipment, reducing the input of staff in the adjusting process is facilitated, and adjusting efficiency and accuracy are improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed for the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic front view of an automatic focusing apparatus for a laser radar light source according to an embodiment of the present invention;
FIG. 2 is a schematic top view of the mount and adjustment assembly of FIG. 1;
FIG. 3 is a cross-sectional view A-A of FIG. 2;
FIG. 4 is an enlarged view of the portion B of FIG. 3;
fig. 5 is a schematic perspective view of a first laser radar light source automatic focusing apparatus according to an embodiment of the present invention;
fig. 6 is a schematic perspective view of a second automatic focusing apparatus for a laser radar light source according to an embodiment of the present invention;
fig. 7 is a schematic three-dimensional structure diagram of an automatic focusing apparatus for a laser radar light source according to an embodiment of the present invention, in which a rotation driving assembly and a cylindrical light-transmitting member are not shown;
FIG. 8 is a schematic view of the structure of FIG. 5 in the direction C, wherein the base body away from the lidar light source is not shown;
fig. 9 is a schematic diagram illustrating a working principle of an automatic focusing method for a laser radar light source according to an embodiment of the present invention;
fig. 10(a), 10(b) and 10(c) are schematic diagrams of histograms of different gray values corresponding to different spot shapes.
In the figure: 1. a light source mounting base; 2. a laser diode; 3. a lens assembly 301, a rotary base; 302. a convex lens; 303. a light bar; 4. a support; 401. a base body; 402. a fixed mount; 5. an adjustment assembly; 501. a slide bar; 502. a rotary driver; 5021. an output shaft; 5022. a drive body; 503. a connecting member; 504. an elastic member; 6. an imaging light screen; 7. an image acquisition unit; 8. a control unit; 9. a channel; 10. an auxiliary clamp ring; 11. positioning pins; 12. a sleeve; 13. a columnar light-transmitting member; 14. and a light-transmitting window.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It is noted that in the present application the term "focusing", i.e. collimating, the dashed line in fig. 1 indicates the optical axis of the lens assembly 3.
Referring to fig. 1 to 9, an automatic focusing apparatus for a laser radar light source according to the present invention will now be described. The automatic laser radar light source focusing device is used for adjusting the focal length of a laser radar light source, the laser radar light source comprises a light source mounting seat 1 with a through hole, a laser diode 2 arranged at one end of the through hole and a lens component 3 which is connected to the other end of the through hole and can move along the axial direction of the through hole, and the automatic laser radar light source focusing device comprises a support 4, an adjusting component 5, an imaging light screen 6, an image acquisition unit 7 and a control unit 8; the support 4 is used for connecting a laser radar light source; the adjusting component is arranged on the support 4 and can be arranged opposite to the laser radar light source, the adjusting component 5 is provided with an adjusting end which can be in butt joint with the lens component 3 and a channel 9 which can enable a light beam emitted by the laser radar light source to pass through, and the adjusting end can drive the lens component 3 to be close to or far away from the laser diode 2; the imaging light screen 6 is arranged at the emergent side of the channel 9, so that the light beam emitted from the lens component 3 can be projected on the imaging light screen 6; the image acquisition unit 7 is used for acquiring the light spot image on the imaging light screen 6 in real time and generating image information; the control unit 8 is respectively in communication connection with the image acquisition unit 7 and the adjusting component 5 so as to control the action of the adjusting end according to the image information.
Wherein, the control unit 8 also has a power supply function and can supply power to the adjusting component 5 and the image acquisition unit 7. In addition, the channel 9 needs to remain coaxial with the optical axis of the lens assembly 3.
Compared with the prior art, the automatic focusing device for the laser radar light source can drive the lens component 3 to move through the adjusting component 5, so that the distance between the lens component 3 and the laser diode 2 is adjusted (namely focusing), light beams emitted by the laser diode 2 and formed after passing through the lens component 3 can completely pass through the channel 9 to be displayed on the imaging light screen 6, the image acquisition unit 7 can acquire light spot images on the imaging light screen 6 in real time to form image information in the adjusting process, the control unit 8 analyzes the image information after acquiring the image information, the accurate adjustment of the lens component 3 is controlled through the image information, manual direct participation is not needed, the automation degree is improved, the time used in the debugging process is shortened, the adjustment consistency can be ensured, and the yield of products is effectively improved.
Specifically, the long axis of the channel 9 is a straight line, so that bending does not occur, and the light beam emitted from the lens assembly 3 is prevented from being shielded.
Referring to fig. 1 to 8, in order to ensure the reliability of the distance adjustment, the lens assembly 3 is screwed with the through hole. The support 4 comprises two oppositely arranged housings 401, wherein one housing 401 is used for connecting the lidar light source and enables the lens assembly 3 to face the other housing 401.
On the premise of threaded fit, the adjusting assembly 5 comprises a rotary sliding rod 501, a rotary driver 502 and a connecting piece 503; a plurality of sliding rods 501 are arranged, two ends of each sliding rod 501 are respectively connected to the two seat bodies 401, and the adjacent sliding rods 501 are parallel to each other; the rotary driver 502 has an output shaft 5021 and a driving body 5022, the driving body 5022 is slidably connected to the sliding rod 501, and the output shaft 5021 forms an adjusting end; the connector 503 is disposed at an end of the output shaft 5021 for connecting with the lens assembly 3, the channel 9 penetrates through the connector 503, the output shaft 5021 and the driving body 5022, and the sliding rod 501 is parallel to the channel 9. The output shaft 5021 of the rotary driver 502 can rotate, and then the lens assembly 3 can be driven to rotate, so that the purpose of focusing is achieved. It should be noted that the coupling 503 needs to maintain an effective connection with the lens assembly 3 to keep the output shaft 5021 and the lens assembly 3 rotating synchronously during the adjustment process, so that the adjustment operation can be precisely controlled.
The lens assembly 3 comprises a rotary base 301, a convex lens 302 and a light stick 303, wherein the rotary base 301 is cylindrical and is in threaded connection with the through hole, a convex ring structure is arranged at the free end of the rotary base 301, a light hole is formed in the inner ring of the convex ring structure, the convex lens 302 is fixed in the rotary base 301, and the light stick 303 is located on the light emitting side of the convex lens 302.
It should be noted that the channel 9 and the output shaft 5021 are required to be coaxial with the optical axis of the lens assembly 3.
Referring to fig. 1 to 8, the support 4 further includes a fixing frame 402 disposed between the two seat bodies 401, the fixing frame 402 is slidably disposed through the sliding rod 501, and the driving main body 5022 is fixed on the fixing frame 402.
Referring to fig. 1 to 8, the rotary driver 502 is a rotary driving motor, the driving body 5022 includes a housing, a stator module fixed in the housing, and a partial rotor disposed in the stator module, the output shaft 5021 penetrates through the housing and is rotatably connected with the housing, and the rotor is sleeved on the periphery of the output shaft 5021.
Referring to fig. 3 and 4, the connecting member 503 drives the lens assembly 3 to rotate by the pressing friction or the absorption force, the adjusting assembly 5 further includes an elastic member 504, the elastic member 504 is disposed between the rotary actuator 502 and the other base 402, and the elastic member 504 is configured to maintain a pre-tightening force for pressing the connecting member 503 against the lens assembly 3.
Specifically, the connecting member 503 is an annular member, and is fixedly disposed at an end of the output shaft 5021, and drives the rotating seat 301 to rotate mainly by an extrusion friction force, and the connecting member 503 may be made of rubber, silica gel, plastic, metal, or the like.
Alternatively, the main body of the connecting member 503 is a ring-shaped member, and a small dish washer is provided on a side facing the spin base 301, and can be connected to the spin base 301 by vacuum suction.
Referring to fig. 1 to 8, in order to simplify the structure of the elastic member 504 and ensure that it can provide effective pressing force, the elastic member 504 is a compression spring, and the compression spring is sleeved on the outer periphery of the sliding rod 501.
Referring to fig. 1 to 7, in order to further effectively fix the lidar light source, the lidar light source automatic focusing apparatus further includes an auxiliary retaining ring 10 and a positioning pin 11 disposed on one of the base bodies 401, the positioning pin 11 can penetrate through the light source mounting base 1 and the auxiliary retaining ring 10, and the auxiliary retaining ring 10 can cooperate with the base body 401 to retain the light source mounting base 1.
Referring to fig. 1 to 7, the laser radar light source automatic focusing apparatus further includes a sleeve 12, wherein the sleeve 12 is sleeved on the outer circumference of the output shaft 5021 and can cover the outer circumference of the lens assembly 3. The sleeve 12 can shield light, prevent light from overflowing and protect the light.
Specifically, the image acquisition unit 7 is an infrared camera. The infrared camera is provided with a camera body, a lens arranged on the camera body and an optical filter covering the end part of the lens, so that the influence of environmental fluctuation on image recognition is reduced, and the image of the light panel can be shot clearly. Because the analysis and the judgment of the image are mainly carried out by processing the gray value of each frame of shot image, the narrow-band filter is selected.
Referring to fig. 1 to 3, 5, 6 and 8, a cylindrical light-transmitting member 13 is disposed at the exit end of the channel 9, the cylindrical light-transmitting member 13 forms a light-transmitting window 14 with a certain curvature, the light-transmitting window 14 is disposed corresponding to the channel 9 and does not block the light beam, and the width of the light-transmitting window 14 in a direction parallel to the radial direction of the channel 9 is greater than the inner diameter of the exit end of the channel 9. Due to the influence of the curvature of the light-transmitting window of the laser radar, collimation correction needs to be considered for the adjustment of light source collimation, and in the embodiment, the columnar light-transmitting piece 13 arranged at the emergent end of the channel 9 is the light source collimation correction device. It should be noted that the light source collimation correcting device may be any element involved in the emission light path that causes light refraction other than the collimating lens, and is not limited to the columnar light-transmitting member 13 having the light-transmitting window 14 in the present embodiment.
The invention also provides an automatic focusing method of the laser radar light source. The laser radar light source automatic focusing method is realized based on the laser radar light source automatic focusing device, and comprises the following steps:
adjusting the distance between the lens component 3 and the laser diode 2 until an initial light spot image is obtained;
performing oscillation type convergence adjustment on the distance between the lens assembly 3 and the laser diode 2, and acquiring a light spot image in real time;
generating image information in real time according to the light spot image, wherein the image information is an image gray distribution histogram, and acquiring histogram distribution width information and histogram gray maximum value information according to the image gray distribution histogram;
judging whether the distribution width of the histogram changes in a first standard range or not and whether the gray maximum value of the histogram changes in a second standard range or not;
when the distribution width of the histogram changes in a first standard range and the gray maximum value of the histogram changes in a second standard range, the adjustment is judged to be finished;
when the change of the distribution width of the histogram exceeds a first standard range and/or the change of the maximum value of the gray scale of the histogram exceeds a second standard range, the adjustment is continued.
It should be noted that, in the process of adjusting the distance between the lens assembly 3 and the laser diode 2, the rotation direction of the rotation driver 502 needs to be controlled to adjust the direction toward which the spot image (or the initial spot image) is clearer. In the adjusting process, if the spot image (or the initial spot image) can be clearer under the condition that the rotary driver 502 is transmitting, the control unit 8 controls the rotary driver 502 to continue transmitting; if the spot image (or the initial spot image) is more blurred when the rotation driver 502 is transmitting, the rotation driver 502 is controlled to reverse.
The invention relates to an automatic focusing method of a laser radar light source, which is characterized in that the aggregation and the divergence of light spots correspond to the change of a gray value, the energy of the light spots is in a gradually concentrated state in the collimation adjusting process, the size of the light spots in the fast axis direction is obviously reduced, the light energy (namely the light power density) of a unit area is gradually increased, the gray value of an image is obviously increased when the gray value of the image is not collimated, an image acquisition unit 7 is used for acquiring the image of the light spots in real time, the image is processed to obtain a real-time image gray distribution histogram, and whether the focusing is in place or not can be visually judged by acquiring the distribution width and. The automatic laser radar light source focusing method is simple to operate, high in response speed and capable of being achieved through automation of equipment, reducing the input of staff in the adjusting process is facilitated, and adjusting efficiency and accuracy are improved. Please refer to fig. 9 for a block diagram of a specific working principle.
Specifically, the method mainly identifies the directions of the fast axis and the slow axis of the light spot, and the fixing mode of the light emitting component is certain, and the installation mode of the chip is certain, namely the directions of the fast axis and the slow axis of the light spot at a certain distance are determined after the light source is collimated. And analyzing the directions and the sizes of a fast axis and a slow axis of each frame of image of the light spots by shooting a real-time image, and determining the adjustment effect.
Specifically, the determination of the ROI region is determined by image binarization segmentation.
Specifically, the first standard range and the second standard range corresponding to different types of radar light sources are different. The histogram distribution width is changed in a first standard range, namely the histogram distribution width is changed in real time during the adjustment process, but all the change values are in the first standard range; the description of the second standard range is also a similar principle and will not be repeated here.
Adjusting the distance between the lens assembly 3 and the laser diode 2 until the initial light spot image is obtained, wherein the adjusting device parameters comprise:
adjusting 7-unit working parameters of the image acquisition unit;
adjusting the size of the channel 9 so that the size of the channel 9 satisfies the relation
D≥d+L×tanθ (1)
Wherein D is the inner diameter of the channel, theta is the divergence angle of the slow axis, L is the length of the channel, and D is the light transmission aperture of the lens assembly.
The purpose of this embodiment is to keep the dimensions of the channel 9 suitable and to avoid obstruction of the light beam exiting the lens assembly 3. This embodiment actually determines the inner diameter of the channel 9 by the effective clear aperture of the lens assembly 3 and the residual divergence angle after collimation.
Wherein, when image acquisition unit 7 is infrared camera, the working parameter of adjustment image acquisition unit 7 specifically includes: and adjusting the exposure time, gain and aperture of the diaphragm of the infrared camera to ensure the overexposure of the light spot image part after collimation.
It should be noted that, by adjusting the exposure time and the gain, the maximum light intensity of the light spot should be ensured to be below the threshold value of binarization, so as to prevent over-saturation and failure to judge the focusing condition. In a general relatively stable environment, the infrared camera shoots light spots and corresponding gray values with certain regularity, the convergence and divergence of the light spots correspond to the size of the gray values, in the collimation adjustment process, the energy of the light spots is gradually concentrated, the fast axis size is obviously reduced, the light energy in a unit area is gradually increased, the gray values of the images are richer than those of the images which are not collimated, namely, the gray values of 0-255 have larger numerical values, and a two-dimensional gray image distribution histogram is obtained by counting the number of the gray values.
As shown in fig. 10(a), 10(b), and 10(c), the image above each image is a light spot photograph, the image gray distribution histogram is below the image, the abscissa in the image gray distribution histogram is a gray level value, the light spot energy gradually concentrates in the collimation process, the light spot is brighter, the gray level is higher, and the ordinate is the number of points of the software-acquired camera pixel, that is, the number of points of different gray levels. Fig. 10(a) shows a relatively blurred state in which light spots are just appearing on the imaging light screen 6, and the number of gray values in the corresponding gray histogram is small; the light spot form of fig. 10(b) appears after the preliminary collimation adjustment, the light spot form gradually changes from a divergent state to an aggregated state, and the number of corresponding gray values is obviously increased; fig. 10(c) shows the complete spot shape adjustment, with the spot nodal region clearly visible and the spot alignment completed.
In order to ensure that the most effective image information can be acquired, the distance between the lens assembly 3 and the laser diode 2 is adjusted until an initial spot image is acquired, and then the method further comprises the following steps: acquiring light spot position information according to the initial light spot image, and acquiring an image region of interest (ROI) according to the light spot position information;
specifically, vibrate formula convergence adjustment is carried out to the interval between lens subassembly 3 and the laser diode 2 to obtain the facula image in real time, specifically include: and performing oscillation type convergence adjustment on the distance between the lens component 3 and the laser diode 2, and acquiring a light spot image in the image region of interest in real time.
In the actual operation process, the operation steps are roughly as follows:
1) preliminarily assembling a laser radar light source, and fixing the laser radar light source on the automatic focusing device of the laser radar light source;
2) an output shaft 5021 of the rotary driver 502 drives the lens component 3 to rotate at a low frequency until the infrared camera shoots a blurred light spot image for the first time, the light spot image is an initial light spot image, and image information of the initial light spot image activates an image recognition program;
3) after the image recognition program is activated, the control unit 8 controls the rotation driver 502 to drive the lens assembly 3 to rotate at high frequency, and the gray scale image judgment and the fast axis recognition program are activated;
4) performing oscillation type convergence adjustment near a focus (namely, a collimation point), so that the fast axis size of a real-time light spot image shot during precession adjustment has a valley value (namely, the fast axis size is the narrowest) and the gray value has a peak value (namely, the gray value is larger and is close to the 255 gray scale direction), wherein the convergence adjustment performed near the two values is the oscillation type convergence adjustment, the histogram gray value and the histogram distribution width corresponding to the light spot image are respectively converged to a first standard range and a second standard range within convergence time through the oscillation type convergence adjustment, and after the collimation adjustment is finished, the image shooting is finished;
5) and (4) taking down the adjusted laser radar light source, resetting each element of the laser radar light source automatic focusing device, and installing a new laser radar light source for adjustment.
The device and the method can form closed-loop control, realize the automatic adjustment of the laser radar light source, save labor force and improve the collimation accuracy and consistency.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. Lidar light source automatic focusing device for adjust the focus of lidar light source, the lidar light source is including the light source mount pad that has the through-hole, locate the laser diode of through-hole one end, and connect in the through-hole other end just can follow the axial displacement's of through-hole lens subassembly, its characterized in that, lidar light source automatic focusing device includes:
the support is used for connecting the laser radar light source;
the adjusting assembly is arranged on the support and can be arranged opposite to the laser radar light source, the adjusting assembly is provided with an adjusting end capable of being in butt joint with the lens assembly and a channel capable of enabling a light beam emitted by the laser radar light source to pass through, and the adjusting end can drive the lens assembly to be close to or far away from the laser diode;
the imaging light screen is arranged on the emergent side of the channel so that the light beams can be projected onto the imaging light screen;
the image acquisition unit is used for acquiring the light spot image on the imaging light screen in real time and generating image information; and
and the control unit is in communication connection with the image acquisition unit and the adjusting assembly respectively so as to control the action of the adjusting end according to the image information.
2. The lidar light source autofocus apparatus of claim 1, wherein the lens assembly is threadably engaged with the through-hole, and the mount comprises two oppositely disposed mounts, one of the mounts being configured to couple to the lidar light source and to direct the lens assembly toward the other mount;
the adjustment assembly includes:
the two ends of each sliding rod are respectively connected to the two seat bodies, and the adjacent sliding rods are parallel to each other;
the rotary driver is provided with an output shaft and a driving main body, the driving main body is connected to the sliding rod in a sliding mode, and the output shaft forms the adjusting end; and
the connecting piece is arranged at the end part of the output shaft and used for being connected with the lens assembly, the channel penetrates through the connecting piece, the output shaft and the driving main body, and the sliding rod is parallel to the channel.
3. The lidar light source autofocus apparatus of claim 2, wherein the connector rotates the lens assembly by a squeezing friction force or a suction force, the adjustment assembly further comprising an elastic member disposed between the rotary actuator and the other of the housings, the elastic member being configured with a preload force that maintains the connector in compression against the lens assembly.
4. The lidar light source autofocus device of claim 3, wherein the resilient member is a compression spring, and the compression spring is disposed around the periphery of the rod.
5. The lidar light source autofocus apparatus of claim 3, further comprising an auxiliary clamp ring, and a positioning pin disposed on one of the base bodies, the positioning pin being capable of penetrating through the light source mount and the auxiliary clamp ring, the auxiliary clamp ring being capable of engaging with the base body to clamp the light source mount.
6. The lidar light source autofocus apparatus of claim 3, further comprising a sleeve disposed around the output shaft and covering the outer periphery of the lens assembly.
7. The lidar light source autofocus apparatus of claim 1, wherein the image capture unit is an infrared camera.
8. The laser radar light source automatic focusing method is realized based on the laser radar light source automatic focusing device according to any one of claims 1 to 7, and is characterized by comprising the following steps of:
adjusting the distance between the lens component and the laser diode until an initial light spot image is obtained;
performing oscillation type convergence adjustment on the distance between the lens assembly and the laser diode, and acquiring a light spot image in real time;
generating image information in real time according to the light spot image, wherein the image information is an image gray distribution histogram, and acquiring histogram distribution width information and histogram gray maximum value information according to the image gray distribution histogram;
judging whether the distribution width of the histogram changes in a first standard range or not and whether the gray maximum value of the histogram changes in a second standard range or not;
when the distribution width of the histogram changes in a first standard range and the gray maximum value of the histogram changes in a second standard range, the adjustment is judged to be finished;
when the change of the distribution width of the histogram exceeds a first standard range and/or the change of the maximum value of the gray scale of the histogram exceeds a second standard range, the adjustment is continued.
9. The lidar light source autofocus method of claim 8, wherein adjusting the distance between the lens assembly and the laser diode until an initial spot image is acquired further comprises adjusting device parameters, and the adjusting device parameters specifically comprise:
adjusting working parameters of the image acquisition unit;
adjusting the size of the channel to make the size of the channel satisfy the relational expression
D≥d+L×tanθ (1)
Wherein D is the inner diameter of the channel, theta is the divergence angle of the slow axis, L is the length of the channel, and D is the light transmission aperture of the lens assembly.
10. The lidar light source autofocus method of claim 9, wherein adjusting the spacing between the lens assembly and the laser diode until an initial spot image is acquired, further comprising:
acquiring light spot position information according to the initial light spot image, and acquiring an image region of interest according to the light spot position information;
the interval between lens subassembly and the laser diode vibrates formula convergence adjustment to obtain the facula image in real time, specifically include:
and performing oscillation type convergence adjustment on the distance between the lens assembly and the laser diode, and acquiring a light spot image in the image region of interest in real time.
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