A laser collimation and adjustment system based on image recognition and electric dimming

Abstract

This invention discloses a laser collimation and adjustment system based on image recognition and electric dimming. It employs a cage-like integrated structure design of an electric aperture + CCD camera to ensure that the center of the aperture, the center of the CCD target surface, and the optical axis of the optical elements are strictly collinear, guaranteeing the consistency and long-term stability of the optical path reference. A miniature electric actuator (2μm resolution) combined with a dual-axis adjustable frame achieves sub-micron level high-precision displacement control, meeting the requirements of high-precision optical systems. The system uses a strategy based on visual recognition of the spot center combined with electric control of the miniature electric actuator. The electric aperture + CCD camera center is used to determine the beam collimation status, accurately locating the spot center and the aperture center, and achieving dynamic closed-loop control. The adjustment amount of the electric actuator is calculated in real time through calibration parameters to adjust the state of the optical elements requiring collimation, ensuring that the spot center, the CCD target surface center, and the aperture center coincide, thus achieving automated laser alignment and collimation.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and specifically to a laser collimation and adjustment system based on image recognition and electric dimming. Background Technology

[0002] In laser processing equipment, whether the beam is collimated and incident at the center of the light inlet of the processing system, and whether the collimated beam is transmitted collimatedly inside the processing head, have a significant impact on the processing quality and accuracy of the laser processing equipment. This is especially true in laser scanning processing devices and multi-path beam splitting processing devices that use galvanometers and field lenses. If the beam is incident off-axis of the optical system, the outgoing beam will not be able to achieve accurate scanning processing.

[0003] In practical applications, such as multi-beam processing heads used in photovoltaic solar panel scribing, a single incident light beam needs to be split into twelve or more beams. During equipment integration, it is crucial to ensure the relative positions of each optical element and the laser beam, as well as the positional relationship between the laser beam and the CNC platform, to guarantee a consistent scribing spacing. If the optical elements in the multi-beam processing head (beam splitting head) are not properly collimated, it can easily lead to changes in spacing and reduced scribing accuracy during the scribing process. However, laser processing equipment must undergo collimation adjustment before use. This process often requires visual inspection and manual adjustment, which can result in low collimation accuracy.

[0004] Patent application number 202310140950.3 discloses an optical path collimation adjustment device, adjustment method, and laser processing equipment. Through the modular design of bracket, connecting frame, and light-emitting lens cover, combined with a detachable light-blocking cross and concentric through-hole structure, the laser beam forms a light spot with double cross marks on the observation plate after passing through the beam expander / contractor. High-precision optical path calibration is achieved by comparing the coincidence of the center of the light spot with the cross marks. It has the advantages of simple structure, intuitive adjustment, and detachable maintenance, and is suitable for precise optical path debugging of laser processing equipment.

[0005] Patent application number 202210856772.X discloses an optical axis calibration device based on laser collimation, including an adapter, a collimation component, a support and locking component, and a photodetector. 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 a precise coaxial structure and horizontal calibration, the alignment of the laser optical axis with the mechanical axis is ensured, achieving high-precision optical path calibration, which is suitable for rapid and accurate debugging of laser systems.

[0006] Patent application number 202411613085.0 discloses a collimation correction device. By setting a reference center, a first alignment point and a second alignment point on the body, and placing them 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 alignment points form two non-collinear projection axes, thereby avoiding error accumulation and significantly improving correction accuracy and reliability. It is suitable for high-precision optical alignment requirements, but its system complexity is high.

[0007] The aforementioned optical collimation systems generally suffer from insufficient adjustment accuracy, typically only achieving millimeter-level precision. Moreover, they mostly employ manual adjustment methods, resulting in low efficiency and poor repeatability, making it difficult to achieve automatic closed-loop control. Furthermore, the alignment process of the optical system heavily relies on the operator's experience, making it difficult to guarantee consistency. Summary of the Invention

[0008] To address the technical deficiencies in existing technologies, this invention provides a laser collimation and adjustment system based on image recognition and electric dimming. It employs a cage-like integrated structure design of an electric aperture + CCD camera to ensure optical path reference consistency. Combined with a dual-axis precision adjustment mechanism using a micro-electric actuator, it achieves high-precision displacement control. Furthermore, it proposes a strategy based on visual recognition of the spot center combined with electric control of the micro-electric actuator. The collimation status is determined using the electric aperture + CCD camera center, accurately locating the spot center and aperture center, and achieving dynamic closed-loop control. By calculating the adjustment amount of the electric actuator in real time through calibration parameters, the spot center, the CCD target center, and the aperture center are made to coincide, achieving automated laser alignment and collimation.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] This invention provides a laser collimation and adjustment system based on image recognition and electric dimming, including an optical platform, a cage-type coaxial device, a laser emitter, and three adjustable lens frames;

[0011] The cage-type coaxial device is mounted on the optical platform. The cage-type coaxial device includes a CCD camera assembly, an electric aperture, and multiple coaxially arranged connecting rods. The CCD camera assembly and the electric aperture are coaxially opposite each other and connected by multiple coaxially arranged connecting rods.

[0012] The optical platform is also equipped with three adjustable lens frames, namely a first adjustable lens frame, a second adjustable lens frame, and a third adjustable lens frame. A laser emitter is installed on the first adjustable lens frame, and optical elements to be collimated and adjusted in the processing optical path are respectively installed on the second and third adjustable lens frames. The second and third adjustable lens frames are sequentially arranged between the first adjustable lens frame and the cage coaxial device. Each of the second and third adjustable lens frames is equipped with two electric actuators for adjusting the angle of the corresponding optical elements.

[0013] The laser emitter is manually adjusted to ensure the laser spot fully enters the CCD target surface of the CCD camera assembly, and the initial center coordinates of the spot in the pixel coordinate system are calculated. The electric actuators corresponding to each optical element are driven to move by a unit angle, and the correspondence between the spot center and the change in spot coordinates on the CCD target surface is calibrated. Based on the deviation of the spot center coordinates and the deviation of the aperture center coordinates, the electric actuators are dynamically adjusted to change the corresponding angles until the center of the laser spot, the center of the camera target surface, and the center of the aperture coincide, achieving the final collimation state.

[0014] The laser emitter serves to collimate the light source in the actual optical path. A small laser source, such as a continuous semiconductor laser, can be used. Its divergence angle is less than 5 mrad, its wavelength is visible light, and its power is low, avoiding damage to the CCD camera and reducing the risk of eye injury. It is also easily adjustable. The laser emitter is fixed to the upper first adjustable frame with mounting holes. During the initial debugging phase, the laser beam emitted by the laser emitter needs to be collimated. This is achieved by simply fixing the cage-type coaxial device to the first adjustable frame and adjusting the first adjustable frame with an electric actuator until the center of the laser spot appears at the center of the CCD target surface.

[0015] Furthermore, the laser emitter is adjusted by the first adjustable lens frame so that the laser spot is completely projected into the CCD target surface, and the position coordinates A of the spot center in the pixel coordinate system are calculated at this time.

[0016] The two electric actuators on the third adjustable lens frame are driven to move by a unit angle respectively. The position coordinates B of the spot center at this time are calculated and compared with the initial position coordinates A to obtain the correspondence between the unit angle change of the two electric actuators on the third adjustable lens frame and the change of the spot coordinates on the CCD target surface.

[0017] The electric aperture is contracted, and the position coordinates C of the aperture center in the pixel coordinate system are calculated through image segmentation and morphological processing. The two electric actuators on the second adjustable frame are driven to move by a unit angle, and the position coordinates D of the new aperture center are calculated. The position coordinates D are compared with the position coordinates C to obtain the correspondence between the unit angle change of the two electric actuators on the second adjustable frame and the change of the light spot coordinates on the CCD target surface.

[0018] Open the electric aperture, calculate the angle that the two electric actuators on the third adjustable frame need to change according to the corresponding change relationship and the coordinate deviation of the laser spot center, and adjust the two electric actuators to change the corresponding angle so that the center of the laser spot is incident on the center of the CCD target surface.

[0019] Shrink the electric aperture, calculate the position of the aperture center in the CCD target surface, calculate the angle that the two electric actuators on the second adjustable frame need to change according to the corresponding change relationship and the aperture center coordinate deviation, adjust the two electric actuators to change the corresponding angle, so that the light spot center in the camera image coincides with the aperture center.

[0020] Open the electric diaphragm to confirm the center position of the laser spot in the camera image, and repeat the above adjustment operation until the center of the laser spot, the center of the camera target surface, and the center of the diaphragm coincide, achieving the final collimation state.

[0021] Furthermore, the position coordinates A of the spot center in the pixel coordinate system are calculated using the pixel centroid method. The two electric actuators on the third adjustable frame each move by a unit angle. The coordinates B of the center of the light spot are The relationship between the unit angle change of the two electric actuators on the third adjustable frame and the change of the spot coordinates on the CCD target surface is calculated using the following formula:

[0022] ;

[0023] in, Let X be the scalar variable representing the change in the X-axis coordinate of one of the electric actuators relative to the center of the CCD target spot. Let Y be the scalar value representing the change in the center coordinates of the CCD target spot with respect to another electric actuator.

[0024] Furthermore, the specific process of shrinking the motorized aperture and calculating the position coordinates C of the aperture center in the pixel coordinate system through image segmentation and morphological processing is as follows:

[0025] After the CCD camera assembly retracts the motorized aperture, it captures an image. The captured color image is converted into a grayscale image. The Otsu adaptive thresholding method is applied to the grayscale image to obtain the globally optimal threshold. The image is then binarized based on this threshold.

[0026] Morphological closing operations are applied to binary images, using a rectangular structuring element with adjustable size to eliminate small holes and noise in the target region, resulting in a connected region with continuous boundaries and closed areas.

[0027] The binary image after the closing operation is traversed. For all points with non-zero pixel values, the geometric centroid of the connected region is calculated based on the relationship between its coordinates and the number of points. This centroid is used as the position coordinate C of the aperture center in the pixel coordinate system, denoted as C. .

[0028] Furthermore, while ensuring that the light spot remains within the CCD target area after movement, the two electric actuators on the second adjustable lens mount are driven to move by a unit angle. Calculate the coordinates D of the center of the new aperture at this moment, and denote it as... The relationship between the unit angle change of the two electric actuators on the second adjustable frame and the change of the spot coordinates on the CCD target surface is calculated using the following formula;

[0029] ;

[0030] in, Let X be the scalar variable representing the change in the X-axis coordinate of one of the electric actuators relative to the center of the CCD target spot. Let Y be the scalar value representing the change in the center coordinates of the CCD target spot with respect to another electric actuator.

[0031] Furthermore, 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:

[0032] The electric aperture is opened, the CCD camera assembly captures an image, and the pixel coordinates of the laser beam center are calculated using the pixel centroid method. ;

[0033] Based on the coordinates of the CCD target center pixel coordinates of the laser beam center Calculate the angle that the two motorized actuators on the third adjustable frame need to be adjusted, i.e.:

[0034]

[0035] in , The angles that need to be adjusted for the two electric actuators are as follows. , For the two electric actuators and the CCD target surface spot center coordinates, the X and Y directions are scalar values ​​representing the changes in the coordinates of the X and Y directions.

[0036] According to the adjustment amount and Adjusting the two motorized actuators on the third adjustable lens mount changes the corresponding angle, so that the center of the laser spot is incident on the center of the CCD target surface. The pixel coordinates of the center of the adjusted laser beam are: .

[0037] Furthermore, the specific process of adjusting the center of the light spot in the camera image to coincide with the center of the aperture stop is as follows:

[0038] Shrink the motorized aperture and calculate the center coordinates of the aperture on the CCD target surface. ;

[0039] Based on the center coordinates of the aperture pixel coordinates of the laser beam center The actual offset is used to calculate the angle that the two motor actuators on the second adjustable frame need to change, i.e.:

[0040]

[0041] in , The angles that need to be adjusted for the two electric actuators are as follows. , For the two electric actuators and the CCD target aperture center coordinates, the X and Y directions are scalar values ​​representing the changes in the coordinates of the center of the aperture in the CCD target surface.

[0042] According to the adjustment amount and Adjusting the two motorized actuators on the second adjustable frame changes the corresponding angle, so that the center of the laser beam coincides with the center of the aperture stop. At this time, the pixel coordinates of the laser beam center change to... .

[0043] Furthermore, the two electric actuators on the second and third adjustable frames are diagonally distributed along the circumferential direction (with opposite vertical positions).

[0044] The adjustable frame is a standard optical adjustable frame with two adjustment knobs: one for horizontal tilt adjustment of the mirror and the other for vertical tilt adjustment. The electric actuators are two-phase stepper motors, providing smooth and precise linear movement control. Each adjustment knob has an electric actuator mounted on it; the linear displacement of the actuators controls the mirror's tilt angle. Therefore, the electric actuator on the tilt control knob moves forward to tilt and backward to tilt. The electric actuators can be selected with a 1 / 2-inch (12 mm or 13 mm) travel.

[0045] This system is suitable for debugging in two states: a) when building an optical system with multiple mirrors during the fabrication optical path setup, each mirror needs to be adjusted individually; b) when adjusting the overall collimation of the fabrication optical path that has already been built.

[0046] a) The process of adjusting each reflector one by one is as follows: For example, when building the optical path, the system needs N reflectors. The reflectors need to be grouped into groups of two according to the direction of optical path transmission, and then each group of reflectors is collimated and adjusted in turn.

[0047] b) To adjust the overall collimation of the established processing optical path, only the first and last optical elements need to be adjusted to ensure the final output beam is collimated. Optical elements include mirrors, beam splitters, and other optical devices that can change the beam transmission path.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The present invention adopts a cage-type integrated structure design of "electric aperture + CCD camera" 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, thus ensuring the consistency of the optical path reference and long-term stability. The micro electric actuator (2μm resolution) combined with the dual-axis adjustable frame realizes sub-micron level high-precision displacement control to meet the requirements of high-precision optical system. The strategy of visually recognizing the spot center combined with electric control of the micro electric actuator is adopted. The collimation of the beam is determined by the center of the electric aperture + CCD camera, the spot center and the aperture center are accurately located, and dynamic closed-loop control is realized. The adjustment amount of the electric actuator is calculated in real time by calibration parameters to adjust the state of the optical element that needs to be collimated, so that the spot center, the center of the CCD target surface and the center of the aperture coincide, thus realizing the automatic alignment and collimation of the laser.

[0050] (2) The present invention uses fewer components and has a simple structure. The mathematical modeling of the offset is easy to calculate and modify, which improves efficiency. The mechanical structure and control algorithm adopted are easy to debug for non-professionals and have low learning difficulty. The accuracy of the present invention depends on the electric actuator. Since the electric actuator has high accuracy, the offset of dimming can be almost ignored. Attached Figure Description

[0051] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0052] Figure 1 This is a flowchart illustrating the overall debugging process of the laser collimation and debugging system in this invention.

[0053] Figure 2 This is a schematic diagram of the structure for laser beam collimation in this invention;

[0054] Figure 3 This is a structural diagram illustrating the collimation adjustment of optical elements in this invention;

[0055] Figure 4 This is a control schematic diagram of the laser collimation and adjustment system in this invention;

[0056] Figure 5 The images are captured by the CCD camera assembly during the collimation adjustment of the reflector in this invention.

[0057] The specific reference numerals in the attached figures are as follows:

[0058] Optical platform 1, CCD camera assembly 2, connecting rod 3, motorized aperture 4, laser emitter 5, first adjustable lens frame 6, second adjustable lens frame 7, third adjustable lens frame 8, first motorized actuator 9, second motorized actuator 10, third motorized actuator 11, fourth motorized actuator 12, fifth motorized actuator 13, sixth motorized actuator 14, motorized actuator controller 15, industrial control computer 16. Detailed Implementation

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] An embodiment of the present invention discloses a laser collimation and adjustment system based on image recognition and electric dimming, such as... Figure 2 and Figure 3 As shown, it includes an optical platform 1, a cage-type coaxial device, a laser emitter 5, three adjustable lens frames, an electric actuator controller 15, and an industrial control computer 16;

[0061] 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 aperture 4, and multiple coaxially arranged connecting rods 3. The CCD camera assembly 2 and the electric aperture 4 are coaxially facing each other and connected by multiple coaxially arranged connecting rods 3.

[0062] The optical platform 1 is also equipped with three adjustable lens frames, namely the first adjustable lens frame 6, the second adjustable lens frame 7, and the third adjustable lens frame 8. The first adjustable lens frame 6 is equipped with a laser emitter 5. The second adjustable lens frame 7 and the third adjustable lens frame 8 are respectively equipped with optical elements to be collimated and adjusted in the processing optical path. The second adjustable lens frame 7 and the third adjustable lens frame 8 are arranged between the first adjustable lens frame 6 and the cage coaxial device. Each of the second adjustable lens frame 7 and the third adjustable lens frame 8 is equipped with two electric actuators for adjusting the angle of the corresponding optical elements. The two electric actuators on the second adjustable lens frame 7 and the third adjustable lens frame 8 are diagonally distributed along the circumferential direction (the vertical positions are opposite). Specifically, the second adjustable lens frame 7 is equipped with a first electric actuator 9 and a second electric actuator 10, and the third adjustable lens frame 8 is equipped with a third electric actuator 11 and a fourth electric actuator 12.

[0063] like Figure 4 As shown, multiple electric actuators are controlled by electric actuator controller 15 respectively, and industrial control computer 16 is connected to electric actuator controller 15, laser emitter 5, CCD camera assembly 2 and electric aperture 4 respectively.

[0064] The laser emitter 5 serves to collimate the light source in the actual optical path. A small laser source, such as a continuous semiconductor laser, can be used. Its divergence angle is less than 5 mrad, its wavelength is visible light, and its power is low, thus avoiding damage to the CCD camera and reducing the risk of eye injury. It is also easily adjustable. The laser emitter 5 is fixed to the upper first adjustable lens mount 6, which has mounting holes. During the initial debugging phase, it is necessary to collimate the laser beam emitted by the laser emitter 5. For example... Figure 2 As shown, simply fixing the cage-type coaxial device onto the first adjustable lens frame 6 and adjusting the first adjustable lens frame 6 using two electric actuators (the fifth electric actuator 13 and the sixth electric actuator 14) until the center of the light spot appears at the center of the CCD target surface can modulate the beam collimation. The specific adjustment method is as follows:

[0065] 1. Manually adjust the laser emitter 5 initially to ensure the laser beam completely enters the CCD target surface (a complete circular spot appears in the CCD image upon visual observation). After the laser beam completely enters the CCD camera assembly 2, the image is captured as shown below. Figure 5 As shown in (a), calculate the coordinates of the laser beam center in the pixel coordinate system at this time. Since the laser spot is not perfectly circular, the pixel centroid method is used to calculate the pixel coordinates of the laser beam center.

[0066] The pixel centroid calculation logic is as follows:

[0067] (1) Convert the color image captured by the CCD camera assembly 2 into a single-channel grayscale image, wherein the non-zero grayscale value corresponds to the effective laser area in the image;

[0068] (2) Traverse each pixel in the grayscale image row by row and column by column. Let the coordinates of a pixel in the grayscale image be... Its grayscale value Perform the following accumulation:

[0069]

[0070]

[0071]

[0072] in , It is the weighted sum of the coordinates of all pixels. This represents the total grayscale value of all pixels.

[0073] (3) The weighted centroid pixel coordinates of the laser beam center for:

[0074]

[0075]

[0076] The obtained centroid results are as follows Figure 5 As shown in (b).

[0077] 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 light spot coordinates on the CCD target surface, the specific process is as follows:

[0078] (1) Under the premise of ensuring that the light spot remains within the range of the CCD target surface after the light spot moves, the industrial control computer 16 issues commands to adjust the fifth electric actuator 13 and the sixth electric actuator 14 respectively, each moving by a unit angle. .

[0079] (2) Obtain the coordinates of the new beam center using the pixel centroid method. ;

[0080] (3) Calculate the change in pixel coordinates corresponding to a unit angle:

[0081]

[0082] in The scalar value representing the change in the X-direction coordinates of the fifth electric actuator 13 and the center of the CCD target spot is given. This is the scalar value representing the change in the Y-axis coordinate of the sixth electric actuator 14 and the center of the CCD target spot. Based on the above steps, the beam center is adjusted to the center of the CCD camera. Since the first adjustable lens mount 6 and the CCD camera assembly 2 are placed coaxially, it can be determined that the beam is now in a collimated state.

[0083] Next, the overall processing optical path or the optical components within it can be collimated and adjusted. This system is suitable for adjustment in two states: a) when building an optical system with multiple mirrors, each mirror needs to be adjusted individually; b) when adjusting the overall collimation of a pre-built processing optical path.

[0084] a) The process of adjusting each reflector one by one is as follows: For example, when building the optical path, the system needs N reflectors. The reflectors need to be grouped into groups of two according to the direction of optical path transmission, and then each group of reflectors is collimated and adjusted in turn.

[0085] b) To adjust the overall collimation of the established processing optical path, only the first and last optical elements need to be adjusted to ensure the final output beam is collimated. Optical elements include mirrors, beam splitters, and other optical devices that can change the beam transmission path.

[0086] The following describes the adjustment process and detailed methods for adjusting the two reflectors:

[0087] like Figure 3 As shown, the collimated laser beam emitted by laser emitter 5 is reflected twice by the first and second reflecting mirrors mounted on the second and third adjustable mirror frames 7 and 8, respectively, before entering the coaxial motorized aperture 4. Since the motorized aperture 4, CCD camera assembly 2 (CCD camera mounting frame, CCD camera), and connecting rod 3 are rigidly connected to form a cage-like structure, the center of the motorized aperture 4 is collinear with and collimated with the center of the CCD camera. If the beam simultaneously satisfies the condition of being at the center of the motorized aperture 4 and the center of the CCD camera, it is determined that the beam is in a collimated state. Figure 1 e state.

[0088] The following describes how to adjust the collimation of the light beam:

[0089] 1. Initially, manually adjust the first and second reflectors to ensure the laser beam is completely incident on the CCD target surface (appearing as a complete circular spot in the image observed by the naked eye). After the laser beam completely enters the CCD camera, the image is captured as follows: Figure 5 As shown in (a), the coordinates A of the laser spot center in the pixel coordinate system are calculated using the pixel centroid method described above. The obtained centroid result is as follows Figure 5 As shown in (b).

[0090] II. Establish the correspondence between the unit angle change of the two electric actuators on the third adjustable frame 8 and the change of the light spot coordinates on the CCD target surface. The specific process is as follows:

[0091] (1) Under the premise of ensuring that the light spot remains within the range of the CCD target surface after movement, adjust the third electric actuator 11 and the fourth electric actuator 12 to move by a unit angle of 1 / 2. ;

[0092] (2) The coordinates B of the new spot center are calculated using the pixel centroid method. ;

[0093] (3) Calculate the pixel coordinate change corresponding to a unit angle: The correspondence between the unit angle change of the two electric actuators on the third adjustable frame 8 and the change of the spot coordinate on the CCD target surface is calculated using the following formula:

[0094] ;

[0095] in, The scalar value representing the change in the X-direction coordinates of the center of the CCD target spot between the third electric actuator 11 and the target surface is given. The scalar value represents the change in the Y-direction coordinates of the center of the CCD target spot with respect to the fourth electric actuator 12.

[0096] III. Retract the motorized aperture 4. The image taken after retracting the motorized aperture 4 is as follows. Figure 5 As shown in (c), the specific process of calculating the position coordinates C of the aperture center in the pixel coordinate system through image segmentation and morphological processing is as follows:

[0097] 1. After the CCD camera assembly 2 retracts the motorized aperture 4, it captures an image. The captured color image is converted to a grayscale image. The Otsu adaptive thresholding method is applied to the grayscale image to obtain the globally optimal threshold. Based on this threshold, the image is binarized. The binarized image is shown below. Figure 5 As shown in (d).

[0098] 2. Morphological closing operations are applied to the binary image. Using a rectangular structuring element with adjustable size, small holes and noise in the target region are eliminated, resulting in a connected region with continuous boundaries and closed areas. The image after morphological closing is shown below. Figure 5 As shown in (e).

[0099] 3. 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 coordinates and the number of points. Use this centroid as the position coordinate C of the aperture center in the pixel coordinate system, denoted as C. The specific steps are as follows:

[0100] (1) Traverse each pixel in the grayscale image row by row and column by column, and record the image coordinates of the effective pixels (i.e., white pixels). ;

[0101] (2) Count the total number of valid pixels. N The sum of the x and y coordinates of all valid pixels is calculated as follows:

[0102]

[0103] ;

[0104] (3) Calculate the centroid pixel coordinates using the average value, i.e.:

[0105]

[0106] The obtained center pixel coordinates of the aperture like Figure 5 As shown in (f).

[0107] IV. Similarly, to establish the correspondence between the unit angle change of the two electric actuators on the second adjustable lens frame 7 and the change of the light spot coordinates on the CCD target surface, the specific process is as follows:

[0108] (1) Under the premise of ensuring that the light spot remains within the range of the CCD target surface after the light spot moves, drive the first electric actuator 9 and the second electric actuator 10 on the second adjustable lens frame 7 to move by a unit angle respectively. ;

[0109] (2) Calculate the position coordinates D of the new aperture center at this time according to the image processing method in step three, and denot it as... ;

[0110] (3) Calculate the pixel coordinate change corresponding to the unit angle: Calculate the correspondence between the unit angle change of the two electric actuators on the second adjustable frame 7 and the change of the light spot coordinate on the CCD target surface using the following formula;

[0111] ;

[0112] in, Let X be the scalar value representing the change in the X-direction coordinates of the first electric actuator 9 and the center of the CCD target spot. The scalar value represents the change in the Y-direction coordinates of the center of the CCD target spot between the second electric actuator 10 and the target surface.

[0113] 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:

[0114] (1) Open the motorized aperture 4, and the CCD camera assembly 2 captures an image. Calculate the pixel coordinates of the center of the laser beam at this time using the pixel centroid method. ;

[0115] (2) Based on the coordinates of the center of the CCD target surface pixel coordinates of the laser beam center The angle that the two electric actuators on the third adjustable frame 8 need to be adjusted is:

[0116]

[0117] in The angle that needs to be adjusted for the third electric actuator 11 The angle that needs to be adjusted for the fourth electric actuator 12 The scalar value representing the change in the X-direction coordinates of the center of the CCD target spot between the third electric actuator 11 and the target surface is given. For the scalar change in the Y-direction coordinates of the center of the CCD target spot with respect to the fourth electric actuator 12;

[0118] (3) Based on the adjustment amount and Adjusting the two electric actuators on the third adjustable lens mount 8 changes the corresponding angle, so that the center of the laser spot is incident on the center of the CCD target surface, as shown in the schematic diagram. Figure 1 As shown in (a), the image taken after alignment with the incident light is as follows: Figure 5 As shown in (g), the center coordinates of the adjusted laser beam are: .

[0119] VI. The specific process of adjusting the center of the light spot in the camera image to coincide with the center of the aperture stop is as follows:

[0120] (1) Shrink the motorized aperture 4 and use the image processing method in step three to calculate the center coordinates of the aperture on the CCD target surface. The obtained center coordinates of the aperture are as follows: Figure 5 As shown in (i), the schematic diagram is as follows: Figure 1 As shown in (b), the captured image is as follows Figure 5 As shown in (h), it can be clearly seen that the center of the laser beam is offset from the center of the aperture. Calculate the offset at this time.

[0121] (2) Based on the coordinates of the aperture center pixel coordinates of the laser beam center The actual offset is used to calculate the angle that the two electric actuators on the second adjustable frame 7 need to change, i.e.:

[0122]

[0123] in The angle that needs to be adjusted for the first electric actuator 9. The angle that needs to be adjusted for the second electric actuator 10 Let X be the scalar value representing the change in the X-direction coordinates of the center of the CCD target aperture between the first electric actuator 9 and the target. The change in the Y-axis coordinate of the center of the second electric actuator 10 and the CCD target aperture is scalar.

[0124] (3) Based on the adjustment amount and Adjusting the two electric actuators on the second adjustable frame 7 changes the corresponding angle, so that the center of the laser beam coincides with the center of the aperture stop. At this time, the pixel coordinates of the laser beam center change to... .like Figure 1 (c) Schematic diagram: The image after adjusting the center of the beam to coincide with the center of the aperture stop is shown below. Figure 5 As shown in (j).

[0125] 7. Open the motorized aperture 4 to confirm the center position of the light spot in the camera image, and repeat steps 5 and 6 above. Figure 1 (a) to Figure 1As shown in (d), until the center of the laser beam, the center of the camera target surface, and the center of the aperture coincide, as shown in (d). Figure 1 As shown in (e). The final collimated beam image is as follows. Figure 5 As shown in (k), the image after shrinking the aperture is as follows: Figure 5 As shown in (l).

[0126] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A laser collimation and adjustment system based on image recognition and electric dimming, characterized in that, Includes an optical platform, a cage-type coaxial device, a laser emitter, and three adjustable frames; The cage-type coaxial device is mounted on the optical platform. The cage-type coaxial device includes a CCD camera assembly, an electric aperture, and multiple coaxially arranged connecting rods. The CCD camera assembly and the electric aperture are coaxially opposite each other and connected by multiple coaxially arranged connecting rods. The optical platform is also equipped with three adjustable lens frames, namely a first adjustable lens frame, a second adjustable lens frame, and a third adjustable lens frame. A laser emitter is installed on the first adjustable lens frame, and optical elements to be collimated and adjusted in the processing optical path are respectively installed on the second and third adjustable lens frames. The second and third adjustable lens frames are sequentially arranged between the first adjustable lens frame and the cage coaxial device. Each of the second and third adjustable lens frames is equipped with two electric actuators for adjusting the angle of the corresponding optical elements. In the initial stage of debugging, the laser light source emitted by the laser emitter is collimated by directly fixing the cage coaxial device on the first adjustable frame. The angle of the laser emitter on the first adjustable frame is adjusted by two electric actuators installed on the first adjustable frame so that the center of the light spot appears at the center of the CCD target surface, that is, the beam of the modulated laser light source is collimated. Then, the optical elements to be collimated and adjusted in the processing optical path are collimated and adjusted, specifically as follows: The laser emitter is adjusted by the first adjustable lens mount so that the laser spot is completely projected into the CCD target surface, and the position coordinates A of the spot center in the pixel coordinate system are calculated at this time. The two electric actuators on the third adjustable lens frame are driven to move by a unit angle respectively. The position coordinates B of the spot center at this time are calculated and compared with the initial position coordinates A to obtain the correspondence between the unit angle change of the two electric actuators on the third adjustable lens frame and the change of the spot coordinates on the CCD target surface. The electric aperture is contracted, and the position coordinates C of the aperture center in the pixel coordinate system are calculated through image segmentation and morphological processing. The two electric actuators on the second adjustable frame are driven to move by a unit angle, and the position coordinates D of the new aperture center are calculated. The position coordinates D are compared with the position coordinates C to obtain the correspondence between the unit angle change of the two electric actuators on the second adjustable frame and the change of the light spot coordinates on the CCD target surface. Open the electric aperture, calculate the angle that the two electric actuators on the third adjustable frame need to change according to the corresponding change relationship and the coordinate deviation of the laser spot center, and adjust the two electric actuators to change the corresponding angle so that the center of the laser spot 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 angle that the two electric actuators on the second adjustable frame need to change according to the corresponding change relationship and the aperture center coordinate deviation, adjust the two electric actuators to change the corresponding angle, so that the light spot center in the camera image coincides with the aperture center. Open the electric diaphragm to confirm the center position of the laser spot in the camera image, and repeat the above adjustment operation until the center of the laser spot, the center of the camera target surface, and the center of the diaphragm coincide, achieving the final collimation state.

2. The laser collimation and adjustment system based on image recognition and electric dimming according to claim 1, characterized in that, The position coordinates A of the spot center in the pixel coordinate system are calculated using the pixel centroid method. L1 (x L1 ,y L1 The two motorized actuators on the third adjustable frame each move by a unit angle N1, and the coordinates B of the light spot center are P. L2 (x L2 ,y L2 The relationship between the unit angle change of the two electric actuators on the third adjustable frame and the change of the spot coordinates on the CCD target surface is calculated using the following formula: Where, δ x1 Let δ be the scalar variable representing the change in the X-direction coordinates of one of the electric actuators and the center of the CCD target spot. y1 Let Y be the scalar value representing the change in the center coordinates of the CCD target spot with respect to another electric actuator.

3. The laser collimation and adjustment system based on image recognition and electric dimming according to claim 2, characterized in that, The specific process of shrinking the motorized aperture and calculating the position coordinates C of the aperture center in the pixel coordinate system through image segmentation and morphological processing is as follows: After the CCD camera assembly retracts the motorized aperture, it captures an image. The captured color image is converted into a grayscale image. The Otsu adaptive thresholding method is applied to the grayscale image to obtain the globally optimal threshold. The image is then binarized based on this threshold. Morphological closing operations are applied to binary images, using a rectangular structuring element with adjustable size to eliminate small holes and noise in the target region, resulting in a connected region with continuous boundaries and closed areas. The binary image after the closing operation is traversed. For all points with non-zero pixel values, the geometric centroid of the connected region is calculated based on the relationship between its coordinates and the number of points. This centroid is used as the position coordinate C of the aperture center in the pixel coordinate system, denoted as P. a1 (x a1 ,y a1 ).

4. The laser collimation and adjustment system based on image recognition and electric dimming according to claim 3, characterized in that, Assuming the light spot remains within the CCD target area after movement, the two motor actuators on the second adjustable frame are moved by a unit angle N2. The coordinates D of the new aperture center are calculated and denoted as P. a2 (x a2 ,y a2 The relationship between the unit angle change of the two electric actuators on the second adjustable frame and the change of the spot coordinates on the CCD target surface is calculated using the following formula; Where, δ x2 Let δ be the scalar variable representing the change in the X-direction coordinates of one of the electric actuators and the center of the CCD target spot. y2 Let Y be the scalar value representing the change in the center coordinates of the CCD target spot with respect to another electric actuator.

5. The laser collimation and adjustment system based on image recognition and electric dimming according to claim 1, characterized in that, 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: The electric aperture is opened, the CCD camera assembly captures an image, and the pixel coordinates P of the laser beam center are calculated using the pixel centroid method. L3 (x L3 ,y L3 ); According to the CCD target center coordinates P c (x c ,y c ) and the pixel coordinates P of the laser beam center L3 (x L3 ,y L3 ) Calculate the angle that the two motor actuators on the third adjustable frame need to be adjusted, that is: Where D x1 D y1 δ represents the angle that needs to be adjusted for each of the two electric actuators. x1 δ y1 For the two electric actuators and the CCD target surface spot center coordinates change in the X and Y directions, scalar values. According to the adjustment amount D x1 With D y1 Adjusting the two motorized actuators on the third adjustable lens mount changes the corresponding angle, so that the center of the laser spot is incident on the center of the CCD target surface. The pixel coordinates of the center of the adjusted laser beam are P. c (x c ,y c ).

6. The laser collimation and adjustment system based on image recognition and electric dimming according to claim 5, characterized in that, The specific process of adjusting the center of the light spot in the camera image to coincide with the center of the aperture stop is as follows: Calculate the center coordinates P of the aperture in the CCD target surface by contracting the motorized aperture. a3 (x a3 ,y a3 ); According to the center coordinates P of the aperture a3 (x a3 ,y a3 ) and the pixel coordinates P of the laser beam center c (x c ,y c The actual offset is used to calculate the angle that the two motor actuators on the second adjustable frame need to change, i.e.: Where D x2 D y2 δ represents the angle that needs to be adjusted for each of the two electric actuators. x2 δ y2 For the two electric actuators and the CCD target aperture center coordinates, the X and Y directions are scalar values ​​representing the changes in the coordinates of the center of the aperture in the CCD target surface. According to the adjustment amount D x2 With D y2 Adjusting the two motorized actuators on the second adjustable frame changes the corresponding angles, so that the center of the laser beam coincides with the center of the aperture stop. At this point, the pixel coordinates of the laser beam center change to P. a3 (x a3 ,y a3 ).

7. The laser collimation and adjustment system based on image recognition and electric dimming according to claim 1, characterized in that, The two electric actuators on the second and third adjustable frames are diagonally distributed along the circumferential direction.

8. The laser collimation and adjustment system based on image recognition and electric dimming according to claim 1, characterized in that, When the optical element to be collimated and adjusted in the optical path is a reflector, the reflectors are grouped into pairs according to the direction of optical path transmission, and then each pair of reflectors is collimated and adjusted in turn.

9. The laser collimation and adjustment system based on image recognition and electric dimming according to claim 1, characterized in that, When adjusting the overall collimation of the already constructed processing optical path, only the first and last optical elements need to be adjusted.

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