Laser alignment debugging system based on image recognition and electric dimming

Abstract

The invention discloses a laser alignment debugging system based on image recognition and electric dimming, which adopts a cage type integrated structure design of an electric diaphragm and a CCD (Charge Coupled Device) camera, ensures that the center of the diaphragm, the center of a CCD target surface and the optical axis of an optical element are strictly collinear, and ensures the reference consistency and long-term stability of an optical path. The micro electric actuator (2 [mu] m resolution) is combined with the double-axis adjustable mirror bracket to realize submicron-level high-precision displacement control and meet the requirements of a high-precision optical system; a strategy of combining visual identification of a light spot center with electric control of a miniature electric actuator is adopted, an electric diaphragm and a CCD camera center are utilized to determine a light beam collimation condition, a light spot center and a diaphragm center are accurately positioned, dynamic closed-loop control is realized, and an adjusting amount of the electric actuator is calculated in real time through calibration parameters. The state of an optical element needing to be collimated is adjusted, so that the center of a light spot coincides with the center of a CCD target surface and the center of a diaphragm, and automatic alignment and collimation of laser are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of laser processing, and in particular to a laser alignment and debugging system based on image recognition and electric dimming. Background Art

[0002] In laser processing equipment, whether the light beam is incident in a collimated manner at the center of the light inlet of the processing system, and whether the collimated light beam is transmitted in a collimated manner inside the processing head, have an important impact on the processing quality and processing accuracy of the laser processing equipment, especially in laser scanning processing devices and multi-path beam splitting processing devices realized by galvanometers and field lenses. If the light beam deviates from the axis of the optical system, the outgoing light beam will not be able to achieve accurate scanning processing.

[0003] In practical applications, such as the multi-path processing head in photovoltaic solar marking, it is necessary to divide a beam of incident light into twelve or more beams. During the equipment integration process, it is necessary to ensure the relative position relationship between each optical component and the laser beam, and also to ensure the position relationship between the laser beam and the CNC platform to ensure a certain marking spacing. If the optical components in the multi-path processing head (beam splitting processing head) are not aligned, it is easy to cause the spacing to change during the marking process and reduce the marking accuracy. However, the laser processing equipment must debug the collimation of the laser light path before use. During the process of debugging the collimation of the laser light path, it is often necessary to observe with the naked eye, and the adjustment also needs to be debugged manually, which will result in low collimation accuracy.

[0004] The patent with application number 202310140950.3 discloses an optical path collimation adjustment device, adjustment method and laser processing equipment. Through the modular design of the bracket, connecting frame and light output mirror cover, combined with a detachable light-blocking cross and concentric through-hole structure, the laser beam passes through the beam expander / reducer mirror and forms a light spot with double cross marks on the observation plate. By comparing the overlap between the center of the light spot and the cross mark, high-precision optical path calibration is achieved. It has the advantages of simple structure, intuitive adjustment, and detachable maintenance. It is suitable for precise optical path debugging of laser processing equipment.

[0005] The patent with application number 202210856772.X discloses an optical axis calibration device based on laser collimation, including a adapter component, a collimation component, a support locking component and a photoelectric detection device. The collimation component adopts a combination design of a phase plate fixing ring, a phase plate, a collimation cylinder with grooves and rectangular holes, and a bubble level. Through precise coaxial structure and horizontal calibration, the alignment of the laser optical axis and the mechanical axis is ensured, and high-precision optical path calibration is achieved. It is suitable for fast and accurate debugging of laser systems.

[0006] The patent with the application number 202411613085.0 discloses a collimation correction device. By setting a reference center, a first pair of alignment points, and a second pair of alignment points on the body, and making them located on mutually parallel collimation planes, a first plane, and a second plane respectively, and maintaining a gap between at least two planes; on the reference plane, the projections of the reference center and the two pairs of alignment points form non - collinear two - projection axes, thus avoiding error accumulation, significantly improving the correction accuracy and reliability, and being applicable to high - precision optical alignment requirements. However, its system complexity is high.

[0007] The above - mentioned optical collimation systems generally have the problem of insufficient adjustment accuracy, usually only reaching millimeter - level accuracy, and mostly adopting manual adjustment methods, which have problems of low efficiency and poor repeatability, and it is difficult to achieve automatic closed - loop control. In addition, the alignment process of the optical system highly depends on the operator's experience and it is difficult to ensure consistency. Summary of the Invention

[0008] To solve the technical defects existing in the prior art, the present invention provides a laser collimation debugging system based on image recognition and electric light regulation. It adopts a cage - type integrated structure design of "electric diaphragm + CCD camera" to ensure the consistency of the optical path reference. Combining with a two - axis precision adjustment mechanism of a micro - electric actuator, it realizes high - precision displacement control, and proposes a strategy based on visual recognition of the center of the light spot and electric control of the micro - electric actuator. It uses the electric diaphragm + CCD camera to determine the collimation situation, accurately locates the center of the light spot and the center of the diaphragm, and realizes dynamic closed - loop control. By calibrating parameters to calculate the adjustment amount of the electric actuator in real time, it makes the center of the light spot coincide with the center of the CCD target surface and the center of the diaphragm, realizing the automatic alignment and collimation of the laser.

[0009] To achieve the above - mentioned purpose, the present invention adopts the following technical solutions: The present invention provides a laser collimation debugging system based on image recognition and electric light regulation, including an optical platform, a cage - type coaxial device, a laser emitter, and three adjustable mirror mounts; The cage - type coaxial device is installed on the optical platform. The cage - type coaxial device includes a CCD camera assembly, an electric diaphragm, and a plurality of coaxially arranged connecting rods. The CCD camera assembly and the electric diaphragm are coaxially and oppositely arranged, and the two are connected by a plurality of coaxially arranged connecting rods; Three adjustable mirror mounts are also installed on the optical platform, namely a first adjustable mirror mount, a second adjustable mirror mount, and a third adjustable mirror mount. The laser emitter is installed on the first adjustable mirror mount. Optical elements to be collimated and debugged in the processing optical path are respectively installed on the second adjustable mirror mount and the third adjustable mirror mount. The second adjustable mirror mount and the third adjustable mirror mount are sequentially arranged between the first adjustable mirror mount and the cage - type coaxial device. Two electric actuators for adjusting the angles of the corresponding optical elements are installed on both the second adjustable mirror mount and the third adjustable mirror mount; Manually adjust the laser emitter so that the laser spot completely enters the CCD target surface of the CCD camera assembly, and calculate the coordinates of the initial spot center in the pixel coordinate system; drive the electric actuators corresponding to each optical element to perform unit-angle movement respectively, and calibrate the corresponding relationship between the spot center and the change of the spot coordinates on the CCD target surface; dynamically adjust the electric actuator to change the corresponding angle based on the deviation of the spot center coordinates and the deviation of the aperture center coordinates until the three points of the laser spot center, the camera target surface center, and the aperture center coincide, reaching the final collimation state.

[0010] Among them, the role of the laser emitter is to replace the light source in the actual optical path for optical path collimation. A small laser source can be used, such as a continuous semiconductor laser, with a divergence angle less than 5 mrad, a visible light wavelength, low power, which can avoid damaging the CCD camera, reduce the risk of eye injury, and is convenient for adjustment. The laser emitter is fixed on the first adjustable mirror mount with mounting holes. At the initial stage of the debugging phase, it is necessary to collimate the laser light source emitted by the laser emitter. Only need to fix the cage coaxial device on the first adjustable mirror mount, and use the electric actuator to adjust the first adjustable mirror mount so that the spot center appears at the center of the CCD target surface to modulate the beam collimation.

[0011] Furthermore, adjust the laser emitter through the first adjustable mirror mount so that the laser spot completely enters the CCD target surface, and calculate the position coordinates A of the spot center in the pixel coordinate system at this time; Drive the two electric actuators on the third adjustable mirror mount to move a unit angle respectively, calculate the position coordinates B of the spot center at this time, and compare with the initial position coordinates A to obtain the corresponding relationship between the unit angle change of the two electric actuators on the third adjustable mirror mount and the change of the spot coordinates on the CCD target surface; Shrink the electric aperture, calculate the position coordinates C of the aperture center in the pixel coordinate system through image segmentation and morphological processing, drive the two electric actuators on the second adjustable mirror mount to move a unit angle respectively, calculate the position coordinates D of the new aperture center at this time, and compare with the position coordinates C to obtain the corresponding relationship between the unit angle change of the two electric actuators on the second adjustable mirror mount and the change of the spot coordinates on the CCD target surface; Open the electric aperture, calculate the angles that the two electric actuators on the third adjustable mirror mount need to change according to the corresponding change relationship and the deviation of the spot center coordinates, and adjust these two electric actuators to change the corresponding angles so that the laser spot center is incident on the center of the CCD target surface; Shrink the electric aperture, calculate the position of the aperture center in the CCD target surface, calculate the angles that the two electric actuators on the second adjustable mirror mount need to change according to the corresponding change relationship and the deviation of the aperture center coordinates, and adjust these two electric actuators to change the corresponding angles so that the spot center in the camera image coincides with the aperture center; Open the electric aperture, confirm the position of the center of the light spot in the camera image, and repeat the above debugging operations until the centers of the laser light spot, the camera target surface, and the aperture center coincide, achieving the final collimation state.

[0012] Further, the position coordinate A of the center of the light spot in the pixel coordinate system is calculated using the centroid method of the image quality as , and the two electric actuators on the third adjustable mirror frame each move a unit angle of , and the position coordinate B of the center of the light spot is , and the corresponding relationship between the unit angle change of the two electric actuators on the third adjustable mirror frame and the change of the light spot coordinates on the CCD target surface is calculated through the following formula: ; where is the scalar of the change in the X direction of the center coordinate of the light spot on the CCD target surface of one of the electric actuators, is the scalar of the change in the Y direction of the center coordinate of the light spot on the CCD target surface of the other electric actuator.

[0013] Further, the specific process of shrinking the electric aperture and calculating the position coordinate C of the center of the aperture in the pixel coordinate system through image segmentation and morphological processing is as follows: After shrinking the electric aperture, the CCD camera module takes an image, converts the captured color image into a grayscale image, applies the Otsu adaptive threshold segmentation method to the grayscale image to obtain the global optimal threshold, and performs binary processing on the image according to this threshold; Apply morphological closing operation to the binary image, use a rectangular structuring element with adjustable size to eliminate small holes and noises in the target area, and obtain a connected area with continuous boundaries and closed regions; Traverse the binary image after the closing operation, for all points with non-zero pixel values, calculate the geometric centroid of the connected area according to the relationship between its coordinate values and the number of points, and use it as the position coordinate C of the center of the aperture in the pixel coordinate system, denoted as .

[0014] Further, on the premise of ensuring that the light spot is still within the range of the CCD target surface after moving, drive the two electric actuators on the second adjustable mirror frame to move a unit angle respectively, calculate the position coordinate D of the new aperture center at this time, denoted as , and calculate the corresponding relationship between the unit angle change of the two electric actuators on the second adjustable mirror frame and the change of the light spot coordinates on the CCD target surface through the following formula; ; where is the scalar of the change in the X direction of the center coordinate of the light spot on the CCD target surface of one of the electric actuators, is the scalar change in the Y direction of the center coordinate of the light spot on the CCD target surface for another electric actuator.

[0015] Further, the specific process of adjusting the center of the laser light spot to be incident on the center of the CCD target surface is as follows: Open the electric diaphragm, and the CCD camera assembly takes an image. Use the centroid method of image quality to calculate the pixel coordinates of the center of the laser beam at this time ; According to the center coordinate of the CCD target surface and the pixel coordinates of the center of the laser beam calculate the angles that the two electric actuators on the third adjustable mirror frame need to be adjusted, that is: where , are the angles that the two electric actuators need to be adjusted respectively, , are the scalar changes in the X and Y directions of the center coordinate of the light spot on the CCD target surface for the two electric actuators; According to the adjustment amounts and , adjust the two electric actuators on the third adjustable mirror frame to change the corresponding angles so that the center of the laser light spot is incident on the center of the CCD target surface. The pixel coordinates of the center of the adjusted laser beam are .

[0016] Further, the specific process of adjusting the center of the light spot in the camera image to coincide with the center of the diaphragm is as follows: Contract the electric diaphragm and calculate the center coordinate of the diaphragm in the CCD target surface ; According to the actual offset between the center coordinate of the diaphragm and the pixel coordinates of the center of the laser beam , calculate the angles that the two electric actuators on the second adjustable mirror frame need to change, that is: where , are the angles that the two electric actuators need to be adjusted respectively, , are the scalar changes in the X and Y directions of the center coordinate of the diaphragm on the CCD target surface for the two electric actuators; According to the adjustment amounts and adjust the two electric actuators on the second adjustable mirror frame to change the corresponding angles so that the center of the laser beam coincides with the center of the diaphragm. At this time, the pixel coordinates of the center of the laser beam are transformed into .

[0017] Furthermore, the two electric actuators on the second adjustable mirror mount and the third adjustable mirror mount are diagonally distributed in the circumferential direction (with opposite up and down positions).

[0018] The adjustable mirror mount is a general optical adjustable mirror mount. There are two adjustment knobs on this adjustable mirror mount. One is for the horizontal swing adjustment of the mirror, and the other is for the vertical pitch adjustment. The electric actuator is a two-phase stepper motor, which can provide smooth and precise linear movement control. Electric actuators are respectively installed on the two adjustment knobs. The deflection angle of the mirror can be controlled by using the linear displacement of the electric actuator. Therefore, for the electric actuator located on the pitch control knob, moving forward represents downward adjustment, and moving backward represents upward adjustment. The electric actuator can be selected with a specification of a stroke of 1 / 2 inch (12 mm or 13 mm).

[0019] This system is applicable to the debugging of two states: a) For an optical system with multiple mirrors when setting up the processing optical path, it is necessary to regulate each mirror one by one; b) To regulate the overall collimation of the already set up processing optical path.

[0020] a) The process of regulating each mirror one by one is as follows: For example, when setting up the processing optical path, if there are N mirrors in the system, the mirrors need to be grouped in pairs according to the optical path transmission direction, and then the collimation regulation of each group of mirrors is carried out in sequence.

[0021] b) To regulate the overall collimation of the already set up processing optical path, only the first and the last optical elements need to be regulated so that the final output beam is collimated. Optical elements include optical devices such as mirrors and beam splitting prisms that can change the beam transmission path.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) In the present invention, a "motorized aperture + CCD camera" cage-type integrated structure design is adopted to ensure that the center of the aperture, the center of the CCD target surface and the optical axis of the optical element are strictly collinear, guaranteeing the consistency of the optical path reference and long-term stability. The micro electric actuator (with a resolution of 2μm) combined with a two-axis adjustable mirror mount realizes sub-micron-level high-precision displacement control, meeting the requirements of high-precision optical systems; adopting a strategy based on visual recognition of the spot center combined with electric control of the micro electric actuator, using the motorized aperture + CCD camera center to judge the collimation of the beam, accurately positioning the spot center and the aperture center, and realizing dynamic closed-loop control. By calibrating parameters, the adjustment amount of the electric actuator is calculated in real time, and the state of the optical element to be collimated is adjusted to make the spot center coincide with the CCD target surface center and the aperture center, realizing the automatic alignment and collimation of the laser.

[0023] (2) The device used in the present invention is less, the structure is simple, the mathematical modeling of the offset is easy to calculate and modify, improving the efficiency; the mechanical structure and control algorithm adopted are easy to debug for non-professionals, with a low starting difficulty; the accuracy of the present invention depends on the electric actuator, and since the accuracy of the electric actuator is high, the offset of the dimming can be almost ignored. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0025] Figure 1 It is the overall debugging flow chart of the laser collimation debugging system in the present invention; Figure 2 It is the structural diagram of collimating the laser beam source in the present invention; Figure 3 It is the structural diagram of collimating and debugging the optical element in the present invention; Figure 4 It is the control schematic diagram of the laser collimation debugging system in the present invention; Figure 5 It is the image captured by the CCD camera assembly during the collimation debugging process of the mirror in the present invention.

[0026] Among them, the specific reference numerals are: Optical platform 1, CCD camera assembly 2, connecting rod 3, electric diaphragm 4, laser emitter 5, first adjustable mirror mount 6, second adjustable mirror mount 7, third adjustable mirror mount 8, first electric actuator 9, second electric actuator 10, third electric actuator 11, fourth electric actuator 12, fifth electric actuator 13, sixth electric actuator 14, electric actuator controller 15, industrial control computer 16. SPECIFIC EMBODIMENTS

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] The embodiment of the present invention discloses a laser collimation debugging system based on image recognition and electric dimming, as Figure 2 and Figure 3 shown, including an optical platform 1, a cage coaxial device, a laser emitter 5, three adjustable mirror mounts, an electric actuator controller 15 and an industrial control computer 16; The cage-type coaxial device is installed on the optical platform 1. The cage-type coaxial device includes a CCD camera assembly 2, an electric diaphragm 4, and a plurality of coaxially arranged connecting rods 3. The CCD camera assembly 2 and the electric diaphragm 4 are coaxially and oppositely arranged, and the two are connected by a plurality of coaxially arranged connecting rods 3; Three adjustable mounts are also installed on the optical platform 1, namely a first adjustable mount 6, a second adjustable mount 7, and a third adjustable mount 8. A laser emitter 5 is installed on the first adjustable mount 6, and optical elements to be collimated and debugged in the processing optical path are respectively installed on the second adjustable mount 7 and the third adjustable mount 8. The second adjustable mount 7 and the third adjustable mount 8 are sequentially arranged between the first adjustable mount 6 and the cage-type coaxial device. Two electric actuators for adjusting the angles of the corresponding optical elements are installed on both the second adjustable mount 7 and the third adjustable mount 8. The two electric actuators on the second adjustable mount 7 and the third adjustable mount 8 are diagonally distributed in the circumferential direction (with opposite upper and lower positions). Specifically, a first electric actuator 9 and a second electric actuator 10 are installed on the second adjustable mount 7, and a third electric actuator 11 and a fourth electric actuator 12 are installed on the third adjustable mount 8.

[0029] As Figure 4 shown, a plurality of electric actuators are respectively controlled by an electric actuator controller 15, and the industrial control computer 16 is respectively controlled and connected to the electric actuator controller 15, the laser emitter 5, the CCD camera assembly 2, and the electric diaphragm 4.

[0030] The function of the laser emitter 5 is to replace the light source in the actual optical path for optical path collimation. A small laser light source can be used, such as a continuous semiconductor laser, with a divergence angle less than 5 mrad, a visible light wavelength, low power, which can avoid damaging the CCD camera, reduce the risk of eye injury, and is convenient for adjustment. The laser emitter 5 is fixed on the first adjustable mount 6 with an installation hole. During the initial stage of the debugging phase, it is necessary to collimate the laser light source emitted by the laser emitter 5. As Figure 2 shown, only need to fix the cage-type coaxial device on the first adjustable mount 6, and use two electric actuators (a fifth electric actuator 13 and a sixth electric actuator 14) to adjust the first adjustable mount 6 so that the center of the light spot appears at the center of the CCD target surface to adjust the beam collimation. The specific control method is as follows: 1. Manually adjust the laser emitter 5 initially to make the laser beam completely enter the CCD target surface (observe with the naked eye that a complete circular spot appears in the CCD image). After the laser beam completely enters the CCD camera assembly 2, take an image as Figure 5 shown in (a), and calculate the center coordinates of the laser beam in the pixel coordinate system at this time . Since the light spot is not a perfect circle, the centroid method of the image quality is used to calculate the pixel coordinates of the center of the laser beam.

[0031] The calculation logic of the centroid method of the image quality is as follows: (1) Convert the color image captured by the CCD camera module 2 into a single-channel grayscale image, where non-zero grayscale values correspond to the effective laser area in the image; (2) Traverse each pixel point in the grayscale image row by row and column by column. Let the coordinates of a certain pixel point in the grayscale image be , and its grayscale value be , and perform the following accumulation: where , are the weighted coordinate sums of all pixels, and is the total grayscale value of all pixels.

[0032] (3) Then the weighted centroid pixel coordinates of the laser beam center are: The obtained centroid result is as shown in Figure 5 (b).

[0033] 2. To establish the correspondence between the unit angle change of the fifth electric actuator 13 and the sixth electric actuator 14 and the change of the spot coordinates on the CCD target surface, the specific process is as follows: (1) On the premise of ensuring that the spot is still within the range of the CCD target surface after moving, use the industrial control computer 16 to issue instructions to adjust the fifth electric actuator 13 and the sixth electric actuator 14 respectively, and each moves a unit angle .

[0034] (2) Obtain the new beam center coordinates according to the image quality centroid method; (3) Calculate the pixel coordinate change amount corresponding to the unit angle: where is the X-direction change scalar of the fifth electric actuator 13 and the spot center coordinates on the CCD target surface, and is the Y-direction change scalar of the sixth electric actuator 14 and the spot center coordinates on the CCD target surface. Based on the above steps, adjust the beam center to the center of the CCD camera. Since the first adjustable mirror mount 6 and the CCD camera module 2 are coaxially placed, it can be determined that the beam is in a collimated state at this time.

[0035] Next, the overall processing optical path or the optical elements in the processing optical path can be collimated and adjusted. This system is applicable to the debugging of two states: a) For an optical system with multiple mirrors when building the processing optical path, each mirror needs to be adjusted one by one; b) Adjust the overall collimation of the already built processing optical path.

[0036] a) The process of adjusting each mirror one by one is as follows: For example, when building the processing optical path, if the system requires N mirrors, the mirrors need to be grouped in pairs according to the optical path transmission direction, and then the collimation adjustment is performed on each group of mirrors in turn.

[0037] b) To adjust the overall collimation of the already built processing optical path, only the first and the last optical elements need to be adjusted to make the finally output beam collimated. The optical elements include optical devices such as mirrors and beam splitting prisms that can change the beam transmission path.

[0038] The following introduces how to carry out the adjustment process and detailed adjustment method for two mirrors: As Figure 3 shown, the collimated laser beam emitted by the laser emitter 5 is reflected twice by the first mirror and the second mirror installed on the second adjustable mirror mount 7 and the third adjustable mirror mount 8, and then enters the coaxial motorized aperture 4. Since the motorized aperture 4, the CCD camera assembly 2 (CCD camera fixed mirror mount, CCD camera), and the connecting rod 3 are rigidly connected to form a cage structure, at this time, the center of the motorized aperture 4 is collinear and collimated with the center of the CCD camera. If the beam satisfies being at the center of the motorized aperture 4 and the center of the CCD camera at the same time, it is determined that the beam is in a collimated state, that is Figure 1 the e state.

[0039] The following introduces how to achieve the process of adjusting the beam collimation: I. Manually adjust the first mirror and the second mirror preliminarily to make the laser beam completely enter the CCD target surface (a complete circular spot appears in the image observed by the naked eye). After the laser beam completely enters the CCD camera, take an image as Figure 5 shown in (a). Calculate the center coordinates A of the laser spot in the pixel coordinate system at this time according to the above-mentioned image quality centroid method as , and the obtained centroid result is as Figure 5 shown in (b).

[0040] II. Establish the correspondence between the unit angle change of the two electric actuators on the third adjustable mirror mount 8 and the change of the spot coordinates on the CCD target surface. The specific process is as follows: (1) On the premise of ensuring that the spot still remains within the range of the CCD target surface after moving, adjust the third electric actuator 11 and the fourth electric actuator 12 respectively to move a unit angle of ; (2) According to the pixel centroid method, the position coordinate B of the new spot center is calculated as ; (3) Calculating the pixel coordinate change corresponding to a unit angle: The corresponding relationship between the unit angle change of the two electric actuators on the third adjustable mirror frame 8 and the change of the light spot coordinates on the CCD target surface is calculated by the following formula: ; in, is the scalar value of the X-direction change of the center coordinates of the third electric actuator 11 and the CCD target surface light spot, It is the scalar of the Y-direction change of the center coordinate of the fourth electric actuator 12 and the CCD target surface light spot.

[0041] 3. Contract the electric diaphragm 4. The image captured after contracting the electric diaphragm 4 is as follows Figure 5 As shown in (c), the specific process of calculating the position coordinate C of the aperture center in the pixel coordinate system through image segmentation and morphological processing is as follows: 1. After the electric aperture 4 is retracted, the CCD camera assembly 2 captures an image, converts the captured color image into a grayscale image, applies the Otsu adaptive threshold segmentation method to the grayscale image, obtains the global optimal threshold, and performs binarization processing on the image based on the threshold. The image after binarization processing is as follows: Figure 5 (d) shown.

[0042] 2. Apply morphological closing operation to the binary image, use a rectangular structure element with adjustable size to eliminate small holes and noise in the target area, and obtain a connected area with continuous boundaries and closed areas. The image after morphological closing operation is as follows: Figure 5 (e) shown.

[0043] 3. Traverse the binary image after the closing operation, and for all points whose pixel values are not zero, calculate the geometric centroid of the connected area based on the relationship between their coordinate values and the number of points, as the position coordinate C of the aperture center in the pixel coordinate system, recorded as , the specific steps are as follows: (1) Traverse each pixel in the grayscale image row by row and column by column, and record the image coordinates of the valid pixels (i.e. white pixels) ; (2) Count the number of all valid pixels N , respectively accumulate the sum of the horizontal and vertical coordinates of all valid pixels, that is: ; (3) Calculate the centroid pixel coordinates by the average value, that is: The obtained pixel coordinates of the center of the aperture As Figure 5 shown in (f).

[0044] IV. Similarly, to establish the correspondence between the unit angle change of the two electric actuators on the second adjustable mirror mount 7 and the change of the spot coordinates on the CCD target surface, the specific process is as follows: (1) On the premise of ensuring that the spot is still within the range of the CCD target surface after moving, drive the first electric actuator 9 and the second electric actuator 10 on the second adjustable mirror mount 7 to move by a unit angle ; (2) Calculate the position coordinates D of the new diaphragm center at this time according to the image processing method in step III, denoted as ; (3) Calculate the pixel coordinate change amount corresponding to the unit angle: Calculate the correspondence between the unit angle change of the two electric actuators on the second adjustable mirror mount 7 and the change of the spot coordinates on the CCD target surface through the following formula; ; where is the scalar of the change in the X direction of the center coordinates of the spot on the CCD target surface by the first electric actuator 9, is the scalar of the change in the Y direction of the center coordinates of the spot on the CCD target surface by the second electric actuator 10.

[0045] V. The specific process of adjusting the center of the laser spot to be incident on the center of the CCD target surface is as follows: (1) Open the electric diaphragm 4, the CCD camera assembly 2 takes an image, and use the centroid method of the image quality to calculate the pixel coordinates of the center of the laser beam at this time ; (2) According to the center coordinates of the CCD target surface and the pixel coordinates of the center of the laser beam, the angles that need to be adjusted by the two electric actuators on the third adjustable mirror mount 8 are: where is the angle that the third electric actuator 11 needs to be adjusted, is the angle that the fourth electric actuator 12 needs to be adjusted, is the scalar of the change in the X direction of the center coordinates of the spot on the CCD target surface by the third electric actuator 11, is the scalar of the change in the Y direction of the center coordinates of the spot on the CCD target surface by the fourth electric actuator 12; (3) According to the adjustment amounts and , adjust the two electric actuators on the third adjustable mirror mount 8 to change the corresponding angles, so that the center of the laser spot is incident on the center of the CCD target surface. The schematic diagram is as shown in Figure 1As shown in (a), the captured image after the incident light passes through the entrance is as follows Figure 5 As shown in (g), the adjusted central coordinates of the laser beam are .

[0046] VI. The specific process of adjusting the center of the light spot in the camera image to coincide with the center of the diaphragm is as follows: (1) Contract the electric diaphragm 4, and use the image processing method in Step 3 to calculate the central coordinates of the diaphragm on the CCD target surface , and the obtained central coordinates of the diaphragm are as shown in Figure 5 (i), and the schematic diagram is as shown in Figure 1 (b), the captured image is as shown in Figure 5 (h). It can be clearly seen that there is a certain offset between the center of the laser beam and the center of the diaphragm. Calculate the offset at this time.

[0047] (2) According to the actual offset between the central coordinates of the diaphragm and the pixel coordinates of the center of the laser beam , calculate the angles that the two electric actuators on the second adjustable mirror frame 7 need to change, that is: Where is the angle that the first electric actuator 9 needs to adjust, is the angle that the second electric actuator 10 needs to adjust, is the scalar change in the X direction between the first electric actuator 9 and the central coordinates of the diaphragm on the CCD target surface, is the scalar change in the Y direction between the second electric actuator 10 and the central coordinates of the diaphragm on the CCD target surface.

[0048] (3) According to the adjustment amounts and , adjust the two electric actuators on the second adjustable mirror frame 7 to change the corresponding angles, so that the center of the laser beam coincides with the center of the diaphragm. At this time, the pixel coordinates of the center of the laser beam are changed to . As shown in the schematic diagram of Figure 1 (c), the image after adjusting the center of the beam to coincide with the center of the diaphragm is as shown in Figure 5 (j).

[0049] VII. Open the electric diaphragm 4 to confirm the position of the center of the light spot in the camera image, and repeat the above Steps V and VI, as shown in Figure 1 (a) to Figure 1 (d), until the three points of the center of the laser beam, the center of the camera target surface, and the center of the diaphragm coincide, as shown in Figure 1 (e). The final image after beam collimation is as shown in Figure 5 (k), and the image after contracting the diaphragm is as shown in Figure 5 (l).

[0050] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A laser collimation debugging system based on image recognition and electric dimming, characterized in that, It includes an optical platform, a cage coaxial device, a laser emitter, and three adjustable mirror mounts; The cage coaxial device is installed on the optical platform. The cage coaxial device includes a CCD camera assembly, an electric diaphragm, and multiple coaxially arranged connecting rods. The CCD camera assembly and the electric diaphragm are coaxially and oppositely arranged, and the two are connected by multiple coaxially arranged connecting rods; Three adjustable mirror mounts are also installed on the optical platform, namely the first adjustable mirror mount, the second adjustable mirror mount, and the third adjustable mirror mount. The laser emitter is installed on the first adjustable mirror mount. Optical elements to be collimated and debugged in the processing optical path are respectively installed on the second adjustable mirror mount and the third adjustable mirror mount. The second adjustable mirror mount and the third adjustable mirror mount are sequentially arranged between the first adjustable mirror mount and the cage coaxial device. Two electric actuators for adjusting the angles of the corresponding optical elements are installed on both the second adjustable mirror mount and the third adjustable mirror mount; Manually adjust the laser emitter to make the laser spot completely enter the CCD target surface of the CCD camera assembly, and calculate the coordinates of the initial spot center in the pixel coordinate system. Drive the electric actuators corresponding to each optical element to move by a unit angle respectively, and calibrate the corresponding relationship between the change of the spot center and the spot coordinates on the CCD target surface. Dynamically adjust the electric actuators to change the corresponding angles based on the deviation of the spot center coordinates and the deviation of the diaphragm center coordinates until the laser spot center, the camera target surface center, and the diaphragm center coincide, reaching the final collimation state.

2. The laser collimation debugging system based on image recognition and electric dimming according to claim 1, wherein Adjust the laser emitter through the first adjustable mirror mount to make the laser spot completely enter the CCD target surface, and calculate the position coordinates A of the spot center in the pixel coordinate system at this time; Drive the two electric actuators on the third adjustable mirror mount to move by a unit angle respectively, calculate the position coordinates B of the spot center at this time, and compare with the initial position coordinates A to obtain the corresponding relationship between the unit angle change of the two electric actuators on the third adjustable mirror mount and the change of the spot coordinates on the CCD target surface; Shrink the electric diaphragm, calculate the position coordinates C of the diaphragm center in the pixel coordinate system through image segmentation and morphological processing. Drive the two electric actuators on the second adjustable mirror mount to move by a unit angle respectively, calculate the position coordinates D of the new diaphragm center at this time, and compare with the position coordinates C to obtain the corresponding relationship between the unit angle change of the two electric actuators on the second adjustable mirror mount and the change of the spot coordinates on the CCD target surface; Open the electric diaphragm, calculate the angles that the two electric actuators on the third adjustable mirror mount need to change according to the corresponding change relationship and the deviation of the spot center coordinates, and adjust these two electric actuators to change the corresponding angles to make the laser spot center incident on the CCD target surface center; Shrink the electric diaphragm, calculate the position of the diaphragm center in the CCD target surface, calculate the angles that the two electric actuators on the second adjustable mirror mount need to change according to the corresponding change relationship and the deviation of the diaphragm center coordinates, and adjust these two electric actuators to change the corresponding angles to make the spot center in the camera image coincide with the diaphragm center; Open the electric diaphragm to confirm the position of the center of the light spot in the camera image, and repeat the above debugging operations until the centers of the laser light spot, the camera target surface, and the diaphragm center coincide, reaching the final collimation state.

3. The laser collimation debugging system based on image recognition and electric dimming according to claim 2, characterized in that The pixel centroid method is used to calculate the position coordinate A of the center of the light spot in the pixel coordinate system: , the two electric actuators on the third adjustable mirror frame each move a unit angle of , the position coordinate B of the center of the light spot is , the corresponding relationship between the unit angle change of the two electric actuators on the third adjustable mirror frame and the change of the light spot coordinates on the CCD target surface is calculated by the following formula: ； Among them, is the scalar of the change in the X direction of the center coordinate of the light spot on the CCD target surface for one of the electric actuators, is the scalar of the change in the Y direction of the center coordinate of the light spot on the CCD target surface for the other electric actuator.

4. The laser collimation debugging system based on image recognition and electric dimming according to claim 3, wherein, Shrink the electric diaphragm. The specific process of calculating the position coordinate C of the diaphragm center in the pixel coordinate system through image segmentation and morphological processing is as follows: After shrinking the electric diaphragm, the CCD camera assembly takes an image, converts the captured color image into a grayscale image, applies the Otsu adaptive threshold segmentation method to the grayscale image to obtain the global optimal threshold, and binarizes the image based on this threshold; Apply morphological closing operation to the binary image, use an adjustable-size rectangular structuring element to eliminate small holes and noise in the target area, and obtain a connected area with continuous boundaries and closed regions; Traverse the binary image after the closing operation. For all points with non-zero pixel values, calculate the geometric centroid of the connected region based on the relationship between its coordinate values and the number of points, and use it as the position coordinate C of the diaphragm center in the pixel coordinate system, denoted as .

5. The laser collimation debugging system based on image recognition and electric dimming according to claim 4, characterized in that, On the premise of ensuring that the light spot remains within the range of the CCD target surface after movement, drive the two electric actuators on the second adjustable mirror frame to move by a unit angle respectively , calculate the position coordinates D of the new diaphragm center at this time, denoted as , and calculate the corresponding relationship between the unit angle change of the two electric actuators on the second adjustable mirror frame and the light spot coordinate change on the CCD target surface through the following formula; ； Among them, is the scalar of the change in the X direction of the center coordinate of the light spot on the CCD target surface for one of the electric actuators, is the scalar of the change in the Y direction of the center coordinate of the light spot on the CCD target surface for the other electric actuator.

6. The laser collimation debugging system based on image recognition and electric dimming according to claim 2, wherein, The specific process of adjusting the center of the laser light spot to be incident on the center of the CCD target surface is as follows: Open the electric diaphragm, and the CCD camera assembly takes an image. Calculate the pixel coordinates of the center of the laser beam at this time using the image quality centroid method ; According to the central coordinates of the CCD target surface and the pixel coordinates of the laser beam center calculate the angles that need to be adjusted by the two electric actuators on the third adjustable mirror mount, namely: Among them , are the angles that two electric actuators need to adjust respectively, , are the change scalars in the X and Y directions of the center coordinates of the light spot on the CCD target surface for the two electric actuators; According to the adjustment amount and , change the corresponding angles of the two electric actuators on the third adjustable mirror frame, so that the center of the laser spot is incident on the center of the CCD target surface, and the pixel coordinates of the center of the adjusted laser beam are .

7. The laser collimation debugging system based on image recognition and electric dimming according to claim 6, wherein, The specific process of adjusting the center of the light spot in the camera image to coincide with the center of the diaphragm is as follows: Shrink the electric diaphragm and calculate the diaphragm center coordinates in the CCD target surface ; According to the diaphragm center coordinates and the actual offset from the center pixel coordinates of the laser beam calculate the angles that need to change for the two electric actuators on the second adjustable mirror mount, i.e.: Among them and are the angles that two electric actuators need to adjust respectively and are the scalar changes in the X and Y directions of the central coordinates of the CCD target plane diaphragm for two electric actuators According to the adjustment amount and adjust the two electric actuators on the second adjustable mirror frame to change the corresponding angle, so that the center of the laser beam coincides with the center of the aperture. At this time, the pixel coordinates of the center of the laser beam are transformed into .

8. The laser collimation debugging system based on image recognition and electric dimming according to claim 1, characterized in that, The two electric actuators on the second adjustable mirror mount and the third adjustable mirror mount are diagonally distributed in the circumferential direction.

9. The laser collimation debugging system based on image recognition and electric dimming according to claim 1, characterized in that When the optical element to be collimated and debugged in the processing optical path is a mirror, group every two mirrors as a group in the optical path transmission direction, and then perform collimation control on each group of mirrors in turn.

10. The laser collimation debugging system based on image recognition and electric dimming according to claim 1, wherein, When adjusting the overall collimation of the already built processing optical path, only the first and the last optical elements need to be adjusted.

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