Laser space straight line calibration system and method

Abstract

The application discloses a kind of laser space straight line calibration system and method, solve the technical problems that present calibration method calibration step is complicated, application range is limited, cannot simultaneously calibrate multiple lasers.The calibration system includes moving module, acquisition module, pose measurement module and data processing module, wherein moving module is used to carry reference laser and laser to be calibrated, and do one-dimensional linear motion in calibration process;Acquisition module includes display panel and imaging detector, display panel is used to receive the laser to be calibrated emitted by laser to be calibrated and form light spot, and imaging detector is used to acquire display panel image information containing light spot;Pose measurement module includes N light spot position detector, respectively used to measure the position information of reference laser on the target surface detected by corresponding light spot position detector;Data processing module is used to receive display panel image information containing light spot and the position information of reference laser, and calculate to obtain space straight line equation.

Description

Technical Field

[0001] This invention relates to a calibration system and method for optical measurement systems, specifically to a high-precision calibration system and method for laser spatial linear equations achieved by moving the emission module. Background Technology

[0002] Line laser measurement systems are widely used in industrial inspection, robot positioning, and 3D reconstruction due to their advantages such as high brightness, strong directionality, and fast response speed. To improve their measurement accuracy, it is usually necessary to calibrate the linear equation of the laser beam in space during the preprocessing stage.

[0003] Existing calibration methods mostly employ the coordinate measuring machine (CMM) method, which achieves high calibration accuracy but is costly. For example, Cao Shuangqian et al., in their paper "Calibration Method for Beam Vector and Zero-Point Position of Laser Ranging Sensor" published in the *Journal of Beijing University of Aeronautics and Astronautics*, Vol. 44, No. 6, June 2018, disclosed a method for calibrating laser ranging sensors using a geometric mathematical model and the least squares method. This method first uses angle calibration theory to obtain the angle between the laser beam and the spindle feed direction. Then, it establishes a coordinate system using a laser tracker. Based on the measurement values ​​of the laser ranging sensor projected onto planes at different angles to the spindle feed direction, the relative coordinates between each laser point are calculated using a geometric mathematical model. Finally, the spatial equation of the laser beam is fitted using the least squares method. However, this method has strict requirements for the installation and attitude control of the laser to be calibrated, the calibration steps are relatively cumbersome, and its application scope is limited.

[0004] In addition, a commonly used calibration method is the auxiliary device calibration method. This method uses a mechanical platform (such as a stepper motor or linear guide rail) to move the laser to be calibrated along a predetermined trajectory, records the coordinate data of the laser point at different positions, and performs spatial straight line fitting based on the coordinate data to obtain the laser spatial straight line equation. However, due to the difficulty in guaranteeing the stability of the mechanical platform, this method is prone to calibration errors. Furthermore, this method can only calibrate a single laser beam and cannot calibrate multiple laser beams simultaneously. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems of existing calibration methods, such as cumbersome calibration steps, limited application scope, easy to cause calibration errors, and inability to calibrate multiple laser beams simultaneously, and to provide a laser spatial linear calibration system and method.

[0006] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0007] A laser spatial straight line calibration system is used to calibrate M laser beams in a spatial straight line in the same coordinate system, where M ≥ 1. Its special feature is that:

[0008] It includes a movement module, a data acquisition module, a pose measurement module, and a data processing module;

[0009] The moving module includes a translation stage and N reference lasers, where N≥3; the translation stage is an electrically controlled one-dimensional translation stage used to perform one-dimensional linear motion during the calibration process, and the direction of movement of the translation stage is defined as the Z-axis; a mounting unit is installed on the translation stage for mounting the reference lasers and the laser to be calibrated; the reference lasers are used to emit reference lasers, and the beam direction of the reference lasers is parallel to the Z-axis;

[0010] The acquisition module includes a display panel and an imaging detector; the display panel is a flat structure and is perpendicular to the Z-axis, used to receive the laser to be calibrated emitted by the laser to be calibrated and form a light spot, and the receiving surface of the display panel is defined as the XOY plane; the imaging detector is set close to the receiving surface of the display panel and is used to acquire the display panel image information containing the light spot.

[0011] The pose measurement module includes N spot position detectors that correspond one-to-one with the reference laser. The N spot position detectors are distributed at different positions at the emission end of the reference laser, and the detection target surface of each spot position detector is perpendicular to the Z-axis. They are used to measure the position information of the reference laser on the detection target surface of the corresponding spot position detector.

[0012] The data processing module is connected to the imaging detector and N spot position detectors respectively. It is used to receive the display panel image information containing the spot and the position information of the reference laser on the detection target surface of the corresponding spot position detector, and calculate the spatial linear equation of the laser to be calibrated.

[0013] This invention also provides a laser spatial line calibration method, including the following steps:

[0014] Step 1: Assemble the laser spatial linear calibration system described above, and define the coordinate system formed by the XOY plane and the Z axis as the display panel coordinate system;

[0015] Step 2: Mount the laser to be calibrated on the mounting unit so that the emitting end of the laser to be calibrated faces the receiving surface of the display panel; at the same time, adjust the orientation of the mounting unit on the translation stage so that the beam direction of each reference laser is parallel to the Z-axis.

[0016] Step 3: Record the position information of each reference laser beam on its detection target surface through the corresponding spot position detector and transmit it to the data processing module; obtain the initial spot coordinates of each reference laser beam through the data processing module, and then obtain the initial straight line equation of the reference laser in the corresponding detector coordinate system; the detector coordinate system refers to the coordinate system corresponding to each spot coordinate detector with the same XY coordinate components as the display panel coordinate system.

[0017] Simultaneously, the image information of the display panel containing the laser spot to be calibrated is recorded by the imaging detector and transmitted to the data processing module. The data processing module then obtains the initial spot coordinates of the laser to be calibrated in the coordinate system of the display panel.

[0018] Step 4: Move the translation stage along the Z-axis once and record the moving distance. Then, obtain the spot coordinates of the reference laser and the laser to be calibrated in the corresponding coordinate system according to the method in Step 3. This will give you the three-dimensional coordinates of the equivalent spatial discrete points of the reference laser and the laser to be calibrated after they have moved once in the corresponding coordinate system.

[0019] Step 5: Move the laser several times according to the method in Step 4 to obtain the three-dimensional coordinates of a series of equivalent spatial discrete points in the corresponding coordinate system after each movement of the reference laser and the laser to be calibrated.

[0020] Step 6: Based on the initial straight line equation obtained in Step 3, and the three-dimensional coordinates of the equivalent space discrete point after each movement of the reference laser obtained in Steps 4 and 5, construct the pose parameter solution equation, and further solve it to obtain the pose change parameters after each movement of the translation stage.

[0021] Step 7: Establish the discrete point coordinate correction equation, and substitute the three-dimensional coordinates of the equivalent spatial discrete points after each movement of the laser to be calibrated obtained in Step 4 and Step 5, as well as the pose change parameters calculated in Step 6, into the discrete point coordinate correction equation to solve for the series of three-dimensional coordinates of the equivalent spatial discrete points after the laser to be calibrated is corrected.

[0022] Step 8: Combining the three-dimensional coordinates of the series of equivalent spatial discrete points after the laser to be calibrated is corrected, and the initial spot coordinates of the laser to be calibrated in the coordinate system of the display panel obtained in Step 3, the spatial straight line equation of the laser to be calibrated is obtained by fitting with the least squares method, thereby completing the spatial straight line calibration of the laser.

[0023] Further, step 1 specifically involves assembling the aforementioned laser spatial linear calibration system, defining the center point of the attitude change of the translation stage relative to the theoretical position as its rotation center point for attitude change, and recording the initial distance between the rotation center point along the Z-axis and the detection target surface of each spot position detector and the display panel, while also recording the initial two-dimensional coordinates of the rotation center point in the display panel coordinate system, as well as the position difference in the XY direction between the center of the detection target surface of each spot position detector and the origin of the display panel coordinate system.

[0024] In step 3, the initial straight line equation is obtained using the following method:

[0025] The initial spot coordinates of each reference laser beam on the detection target surface of the corresponding spot position detector are obtained by the data processing module. Then, combined with the position difference in the XY direction between the center of the detection target surface of each spot position detector and the origin of the display panel coordinate system recorded in step 1, N detector coordinate systems are established, and the initial straight line equation of the reference laser in the corresponding detector coordinate system is obtained.

[0026] Furthermore, in step 6, the equation for solving the pose parameters is:

[0027]

[0028] In the formula, and They represent the first i After the second move k The beam reference laser's spot coordinates in the corresponding detector coordinate system. k =1,2,3...N; i Indicates the order of movement; and They represent the first k The initial spot coordinates of the reference laser beam in the corresponding detector coordinate system before the laser beam moves; This represents the Z-coordinate component of the rotation center point of the translation stage in each detector coordinate system. ,in, Indicates the rotation center point of the translation stage relative to the first... k The initial distance along the Z-axis of the detection target surface of each spot position detector. Indicates the movement of the translation stage i The total distance moved relative to the initial position in the Z-axis direction after this; Indicates the movement of the translation stage i The attitude change angle after the subsequent rotation around the Y-axis; Indicates the movement of the translation stage i The attitude change angle after the next rotation around the X-axis; Indicates the movement of the translation stage i The attitude change angle after the next rotation around the Z-axis; and These represent the movement of the translation stage. i The offset that occurs relative to the theoretical position in the X-axis and Y-axis directions after this.

[0029] Furthermore, in step 7, the discrete point coordinate correction equation is:

[0030]

[0031] In the formula, Indicates the first i After the second move m The three-dimensional coordinates of the equivalent spatial discrete points after laser correction are determined. m =1,2,3...M; and They represent the first i After the second move m The coordinate values ​​of the laser spot in the display panel coordinate system are to be determined. Indicates the first i The z-coordinate of the rotation center point of the translation stage in the coordinate system of the display panel after the next movement, and , L This indicates the initial distance between the display panel and the rotation center point of the translation stage along the Z-axis. and These represent the initial two-dimensional coordinates of the rotation center point of the translation stage in the coordinate system of the display panel.

[0032] Furthermore, this invention also provides another laser spatial line calibration system, which is characterized by:

[0033] It includes a movement module, a data acquisition module, a pose measurement module, and a data processing module;

[0034] The moving module includes a translation stage; the translation stage is an electrically controlled one-dimensional translation stage, used to perform one-dimensional linear motion during the calibration process, and the direction of movement of the translation stage is defined as the Z-axis; a mounting unit is installed on the translation stage for mounting the laser to be calibrated;

[0035] The acquisition module includes a display panel and an imaging detector; the display panel is a flat structure and is perpendicular to the Z-axis, used to receive the laser to be calibrated emitted by the laser to be calibrated and form a light spot, and the receiving surface of the display panel is defined as the XOY plane; the imaging detector is set close to the receiving surface of the display panel and is used to acquire the display panel image information containing the light spot.

[0036] The pose measurement module includes a first theodolite, a first reflector, a second theodolite, and a second reflector. The first reflector is mounted on the mounting unit, and its reflecting surface is parallel to the XOY plane and far away from the display panel. The first theodolite is located on the reflected light path of the first reflector and is used to measure the attitude change angle of the laser to be calibrated rotating around the X-axis and Y-axis.

[0037] The second reflector is mounted on the mounting unit, and the reflecting surface of the second reflector is perpendicular to the XOY plane. The second theodolite is located on the reflected light path of the second reflector and is used to measure the attitude change angle of the laser to be calibrated rotating around the Z-axis.

[0038] The data processing module is connected to the imaging detector, the first theodolite, and the second theodolite, respectively, and is used to receive the display panel image information containing the light spot, as well as the attitude change angles of the laser to be calibrated rotating around the X-axis, Y-axis, and Z-axis, and to calculate the spatial linear equation of the laser to be calibrated.

[0039] Furthermore, it also includes a guide rail, on which the second theodolite is mounted and can slide along the guide rail, with its sliding direction consistent with the movement direction of the translation stage.

[0040] Furthermore, the first and second reflectors are integrated planar reference mirrors with orthogonal reflecting surfaces.

[0041] This invention also provides another method for laser spatial line calibration, comprising the following steps:

[0042] Step 1: Assemble the other laser spatial linear calibration system described above, and define the coordinate system formed by the XOY plane and the Z axis as the display panel coordinate system;

[0043] Step 2: Install the laser to be calibrated on the mounting unit, so that the emitting end of the laser to be calibrated faces the receiving surface of the display panel;

[0044] Step 3: Record the image information of the display panel containing the laser spot to be calibrated through the imaging detector, and transmit it to the data processing module. Then, obtain the initial spot coordinates of the laser to be calibrated in the coordinate system of the display panel through the data processing module.

[0045] Step 4: Move the translation stage along the Z-axis once and record the distance it moves. Then, following the method in Step 3, obtain the coordinates of the laser spot in the display panel coordinate system after the laser to be calibrated moves once. Then, obtain the three-dimensional coordinates of the equivalent spatial discrete point in the display panel coordinate system after the laser to be calibrated moves once. At the same time, measure the attitude change angle of the laser to be calibrated after it moves once using the first theodolite and the second theodolite.

[0046] Step 5: Move the laser several times according to the method in Step 4 to obtain the three-dimensional coordinates and attitude change angles of a series of equivalent spatial discrete points after each movement of the laser to be calibrated;

[0047] Step 6: Establish the discrete point coordinate correction equation, and substitute the three-dimensional coordinates of the equivalent spatial discrete points and the corresponding attitude change angles of each movement of the laser to be calibrated obtained in Step 4 and Step 5 into the discrete point coordinate correction equation to solve for the three-dimensional coordinates of a series of equivalent spatial discrete points after the laser to be calibrated is corrected.

[0048] Step 7: Combining the three-dimensional coordinates of the series of equivalent spatial discrete points after the laser to be calibrated is corrected, and the initial spot coordinates of the laser to be calibrated in the display panel coordinate system obtained in Step 3, the least squares method is used to fit the spatial straight line equation of the laser to be calibrated, thereby completing the spatial straight line calibration of the laser.

[0049] Furthermore, in step 6, the discrete point coordinate correction equation is:

[0050]

[0051] In the formula, Indicates the first i After the second move m The three-dimensional coordinates of the equivalent spatial discrete points after laser correction are determined. m =1,2,3...M; and They represent the first i After the second move m The coordinate values ​​of the laser spot in the display panel coordinate system are to be determined. Indicates the first i The z-coordinate of the rotation center point of the translation stage in the coordinate system of the display panel after the next movement, and , L This indicates the initial distance between the display panel and the rotation center point of the translation stage along the Z-axis. Indicates the movement of the translation stage i The total distance moved relative to the initial position in the Z-axis direction after this; and These represent the initial two-dimensional coordinates of the rotation center point of the translation stage in the display panel coordinate system; , , They represent the translation platforms respectively. i The attitude change information measured by the first and second theodolites after the second movement, among which... Indicates the movement of the translation stage i The attitude change angle after the subsequent rotation around the Y-axis; Indicates the movement of the translation stage iThe attitude change angle after the next rotation around the X-axis; Indicates the movement of the translation stage i The attitude change angle after the next rotation around the Z-axis.

[0052] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0053] (1) The present invention provides a laser spatial linear calibration system, comprising a moving module, an acquisition module, a pose measurement module, and a data processing module. The moving module carries a reference laser and a laser to be calibrated, and performs one-dimensional linear motion during the calibration process. The acquisition module includes a display panel and an imaging detector. The display panel receives the laser emitted by the laser to be calibrated and forms a light spot. The imaging detector acquires image information of the display panel containing the light spot. The pose measurement module includes N light spot position detectors corresponding one-to-one with the reference laser, each used to measure the position information of the reference laser on the detection target surface of the corresponding light spot position detector. The data processing module receives the image information of the display panel containing the light spot and the position information of the reference laser on the detection target surface of the corresponding light spot position detector, and calculates the spatial linear equation of the laser to be calibrated. This calibration system constructs an attitude calculation framework using multiple laser beams, utilizes N reference laser beams as reference beams, and ultimately achieves high-precision calculation of five-degree-of-freedom pose change parameters, resulting in high calibration efficiency and accuracy.

[0054] (2) The laser spatial linear calibration system provided by the present invention adopts a high-precision display panel photogrammetry method to achieve simple and fast measurement and improve calibration efficiency.

[0055] (3) The laser spatial linear calibration system provided by the present invention has strong hardware tolerance, which allows the translation stage to undergo angular graded attitude changes and wire-level mechanical position errors without affecting the calibration accuracy.

[0056] (4) The laser spatial line calibration system provided by the present invention has strong anti-interference ability. It can still accurately extract the centroid position of the spot through geometric correction and distortion correction algorithms even if the imaging detector shakes or the shooting angle and position change during the calibration process.

[0057] (5) The laser spatial linear calibration method provided by the present invention derives the ideal spot coordinates based on the pose parameters, and then separates the motion error of the translation stage from the inherent offset of the laser beam to achieve reverse compensation of the mechanical error of the translation stage, and finally achieves a correction accuracy of 0.01mm.

[0058] (6) The laser spatial straight line calibration method provided by the present invention can simultaneously realize the spatial straight line calibration of multiple laser beams in the same coordinate system. For line laser measurement systems containing multiple laser beams, the calibration efficiency is greatly improved.

[0059] (7) The calibration accuracy of this method does not depend on the measurement distance. It is not only suitable for short-distance laser linear calibration, but also can achieve high-precision calibration when the measurement distance is far, and has high adaptability.

[0060] (8) Another laser spatial linear calibration system provided by the present invention can be applied to occasions where the axial error of the translation stage can be ignored or the calibration accuracy requirement is low, thereby improving the adaptability to different application scenarios. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the structure of a first embodiment of the laser spatial line calibration system of the present invention;

[0062] Figure 2 This is a schematic diagram of the structure in Embodiment 1 of the laser spatial linear calibration method of the present invention, showing the change in pose of the laser to be calibrated relative to the ideal state after it is moved.

[0063] Figure 3 This is a schematic diagram of the structure of Embodiment 2 of the laser spatial line calibration system of the present invention.

[0064] The attached figures are labeled as follows:

[0065] 1-First laser to be calibrated, 2-Second laser to be calibrated, 3-Third laser to be calibrated, 4-First reference laser, 5-Second reference laser, 6-Third reference laser, 7-Translation stage, 8-First reflector, 9-Second reflector, 10-Guide rail, 11-Second theodolite, 12-First theodolite, 13-First spot position detector, 14-Second spot position detector, 15-Third spot position detector, 16-Display panel, 17-Imaging detector, 18-Position of the laser to be calibrated without pose change, 19-Position of the laser to be calibrated after pose change. Detailed Implementation

[0066] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0067] Example 1

[0068] like Figure 1 As shown, this embodiment provides a laser spatial line calibration system, including a movement module, a data acquisition module, a pose measurement module, and a data processing module. Figure 1 (Not shown in the image).

[0069] The moving module includes a translation stage 7 and multiple reference lasers. The translation stage 7 is an electrically controlled one-dimensional translation stage used for one-dimensional linear motion during calibration. In this embodiment, the movement direction of the translation stage 7 is defined as the Z-axis. A mounting unit is installed on the translation stage 7 to mount the reference lasers and the lasers to be calibrated, and moves synchronously with the translation stage 7 along the Z-axis. The number of lasers to be calibrated, M≥1, is used to emit lasers at arbitrary angles. This embodiment uses three lasers as an example: the first calibration laser 1, the second laser to be calibrated, and the third laser to be calibrated, 3. The number of reference lasers, N≥3, is used to emit reference lasers, and the beam direction of the reference lasers is parallel to the Z-axis. This embodiment uses three reference lasers as an example: the first reference laser 4, the second reference laser 5, and the third reference laser 6.

[0070] The acquisition module includes a display panel 16 and an imaging detector 17. The display panel 16 is a flat plate structure, perpendicular to the Z-axis, used to receive the laser emitted by the laser to be calibrated and form a light spot. The receiving surface of the display panel 16 is defined as the XOY plane. Multiple feature targets are set on the display panel 16. The two-dimensional coordinate system of the display panel 16 can be determined according to the position of the feature targets, and thus together with the Z-axis, they form the display panel coordinate system. The display panel 16 has diffuse reflection characteristics, so it will form a light spot after receiving the laser to be calibrated. The centroid of the light spot can be equivalent to a two-dimensional discrete point used to fit the laser space straight line. With the translation amount of the translation stage 7, a series of three-dimensional discrete points on the laser space path can be constructed.

[0071] The imaging detector 17 is positioned close to the receiving surface of the display panel 16 to acquire image information of the display panel containing light spots.

[0072] The pose measurement module includes three spot position detectors (PSDs) corresponding to the reference lasers. These three PSDs (first spot position detector 13, second spot position detector 14, and third spot position detector 15) are distributed at different positions at the emission ends of the three reference lasers. The detection target surface of each PSD is perpendicular to the Z-axis. They are used to measure the position information of the reference laser on the corresponding PSD detection target surface. This information can be used to calculate the pose error of the reference laser and the laser to be calibrated during the movement of the translation stage 7 (the pose errors of the two are the same). The X and Y coordinate axes of each PSD are consistent with the coordinate system of the calibration system's display panel.

[0073] The data processing module is connected to the imaging detector 17 and three spot position detectors respectively. It is used to receive the display panel image information containing the spot and the position information of the reference laser on the detection target surface of the corresponding spot position detector, and calculate the spatial linear equation of the laser to be calibrated.

[0074] The principle of laser spatial line calibration in this embodiment is as follows: Using the collected coordinate data of discrete points in the space of the laser to be calibrated and the coordinate data of discrete points in the space of a reference laser, combined with a spot coordinate correction algorithm, the measurement error of the laser discrete point coordinates caused by the 7-position pose error of the translation stage is separated, and finally, the spatial line equation of the laser to be calibrated is obtained by fitting. The specific calibration method is as follows:

[0075] Step 1: Assemble the laser spatial linear calibration system described in this embodiment. Define the center point of the attitude change of the translation stage 7 relative to the theoretical position as its rotation center point C, and record the initial distance between this rotation center point and the detection target surface of each spot position detector in the Z-axis direction. The initial distance between the display panel 16 and the display panel 16 Simultaneously, the position difference in the XY direction between the center of the detector target surface and the origin of the coordinate system of the display panel for each spot position is recorded. And the initial two-dimensional coordinates of the rotation center point in the display panel coordinate system. .

[0076] For a single lead screw driven translation stage 7, the center of the lead screw can be defined as the rotation center point C for the pose change of the translation stage 7.

[0077] Step 2: Install the three lasers to be calibrated on the mounting unit so that the emitting end of each laser is facing the receiving surface of the display panel 16; at the same time, adjust the posture of the mounting unit on the translation stage 7 so that the beam direction of each reference laser is parallel to the Z-axis, and the X and Y coordinates of each pair of projection points of each reference laser on the XOY plane are different.

[0078] Step 3: Since the detection target surface of each spot position detector is perpendicular to the Z-axis, it is parallel to the XOY plane. Each spot position detector records the position information of the corresponding reference laser on its detection target surface and transmits it to the data processing module. Then, the data processing module obtains the initial spot coordinates of the reference laser on the detection target surface of the corresponding spot position detector and compares these initial spot coordinates with the position difference recorded in Step 1. Subtracting these values ​​establishes N detector coordinate systems with the same XOY coordinate components as the display panel coordinate system. This, in turn, yields the initial linear parametric equations (vector form) for each reference laser beam in its corresponding detector coordinate system:

[0079] ,

[0080] in, Indicates the first k The linear equation of the reference laser beam. k =1, 2…N; , indicating the initial state of the firstk The beam reference laser's spot coordinates in the corresponding detector coordinate system. Let be the linear direction vector of the reference laser before the pose change, and , z This indicates that the Z-coordinate is used as a parameter in the equation of the straight line.

[0081] Simultaneously, the imaging detector 17 records image information of the display panel containing the laser spot to be calibrated, and transmits it to the data processing module. The data processing module then obtains the initial spot coordinates of the laser to be calibrated in the coordinate system of the display panel. , m Indicates the first m One laser to be calibrated.

[0082] Step 4: Move the translation stage 7 along the Z-axis once, record the moving distance, and obtain the three-dimensional coordinates of the equivalent spatial discrete points of the reference laser and the laser to be calibrated in the corresponding coordinate system after moving once, following the method in Step 3.

[0083] Specifically, the movement of the translation stage 7 is equivalent to the synchronous movement of each spot position detector and display panel 16 along the Z-axis to measure the three-dimensional coordinates of the equivalent spatial discrete points of the corresponding laser beam. During this process, the two-dimensional coordinates of the reference laser and the laser to be calibrated after one movement are obtained according to the method in step 3, and then combined with the movement distance along the Z-axis and the initial distance recorded in step 1. and This allows us to obtain the three-dimensional coordinates of the equivalent spatial discrete points of the reference laser and the laser to be calibrated in the corresponding detector coordinate system and display panel coordinate system.

[0084] Step 5: Move the laser several times as described in Step 4 to obtain the three-dimensional coordinates of a series of equivalent spatial discrete points in the corresponding coordinate system after each movement of the reference laser and the laser to be calibrated. (The text then repeats the steps for each movement.) k Taking the reference laser beam as an example, after one movement, the beam spot coordinates in the corresponding detector coordinate system are: At this point, the parametric equation of the line changes to the following after pose transformation:

[0085] (1)

[0086] in, R Let be the rotation matrix and transformation matrix of the reference laser, and:

[0087]

[0088] These represent the attitude change angles of the reference laser in the Y-axis, X-axis, and Z-axis directions, respectively. It is a translation vector; This represents the rotation center point where the translation stage 7 undergoes attitude changes. This center point is also the rotation center point where the mounting unit, the laser to be calibrated, and the reference laser undergo attitude changes. Based on the driving structure characteristics of the electrically controlled one-dimensional translation stage, this embodiment approximates the center of the drive screw as the rotation center point where the translation stage 7 undergoes attitude changes relative to its theoretical position. This coordinate can be directly measured.

[0089] Equation (1) can be written in matrix form as follows:

[0090] (2)

[0091] in The rotation center point at which the translation stage 7 undergoes attitude change is at the [missing information - likely a specific point or location]. k The beam coordinates of the reference laser in the detector coordinate system. Since the beam direction of the reference laser is parallel to the Z-axis, then... At this point, equation (2) is further adjusted to:

[0092] (3)

[0093] Figure 2 The image shows the position 18 of the laser to be calibrated without any pose change and the position 19 of the laser to be calibrated after a pose change. For the first... i The reference laser after the pose change moves a total distance relative to its initial position. The coordinates of the light spot in the detector coordinate system corresponding to the light spot position are: , of z Coordinates are Therefore, In the equation of the line (3) Thus, the parameters are obtained. z ,Right now:

[0094] (4)

[0095] Substituting equation (4) into equation (3), we obtain the coordinates of the reference laser spot on the detector target surface at the corresponding spot position after the pose change. ,Right now:

[0096] (5)

[0097] After neglecting the second-order minor quantities containing angles, equation (5) becomes:

[0098] (6)

[0099] Since the translation position error of a high-precision electrically controlled one-dimensional translation stage is on the order of 0.01 mm, and the attitude error limit is in the angular order, therefore, in equation (6) , If we can ignore it, then equation (6) can be simplified to:

[0100] (7)

[0101] For the laser to be calibrated, the matrix of its pose change R and t Same as the reference laser.

[0102] It should be noted that when the spatial distribution range of the laser to be calibrated at the acquisition module is small, the display panel 16 can also be replaced by a spot position detector; similarly, the acquisition of the spot position change information of the reference laser can also be achieved by the display panel 16 and the corresponding optical imaging detector 17, and multiple display panels 16 can share one optical imaging detector 17.

[0103] Step 6: Based on the initial straight line equation obtained in Step 3, and the three-dimensional coordinates of the equivalent space discrete points after each movement of the reference laser obtained in Steps 4 and 5, construct the pose parameter solution equation, and further solve to obtain the pose change parameters of the reference laser after each movement.

[0104] From equation (7), we can obtain:

[0105] (8)

[0106] In the above formula:

[0107]

[0108] Equation (8) simplifies to:

[0109] (9)

[0110] Further rewriting equation (9) as:

[0111] (10)

[0112] In equation (10), and They represent the first i After the second move k The beam reference laser's spot coordinates in the corresponding detector coordinate system. i Indicates the order of movement; and They represent the first k The initial spot coordinates of the reference laser beam in the corresponding detector coordinate system before the laser beam moves; This represents the Z-coordinate component of the rotation center point of the translation stage 7 in the corresponding detector coordinate system, and , Indicates the movement of translation stage 7 i The total distance moved relative to the initial position in the Z-axis direction after this; These represent the movement of translation stage 7. i The subsequent pose change parameters are also the pose change parameters of the reference laser and the laser to be calibrated. Indicates the movement of translation stage 7 i The attitude change angle after the subsequent rotation around the Y-axis; Indicates the movement of translation stage 7 i The attitude change angle after the next rotation around the X-axis; Indicates the movement of translation stage 7 i The attitude change angle after the next rotation around the Z-axis; and These represent the movement of translation stage 7. i The offset that occurs relative to the theoretical position in the X-axis and Y-axis directions after this.

[0113] The known quantities in equation (10) are: The unknowns are: By constructing six equations using three reference laser beams according to the above method, five pose change parameters can be obtained by solving them. .

[0114] Step 7: Establish the discrete point coordinate correction equation, and substitute the three-dimensional coordinates of the equivalent spatial discrete points after each movement of the laser to be calibrated obtained in Steps 4 and 5, as well as the pose change parameters calculated in Step 6, into the discrete point coordinate correction equation to solve for the series of equivalent spatial discrete point three-dimensional coordinates after the laser to be calibrated is corrected.

[0115] The coordinates of the laser spot in the display panel coordinate system after the laser pose changes are to be calibrated. The point on the laser line when the laser to be calibrated has not changed its pose can be directly measured. coordinate It can be derived from a point. The coordinates are obtained through the following transformation:

[0116] (11)

[0117] Substitution And neglecting second-order minor quantities, equation (11) becomes:

[0118] (12)

[0119] in, , , , , , This can be disregarded. Based on the characteristics of the drive structure of the electrically controlled one-dimensional translation stage, the center of the drive screw is approximately equivalent to the rotation center of the translation stage 7 for each pose change. , The estimation error is . and t zi This will cause the Z-coordinate error in the above equation. , This leads to errors in the X and Y coordinates of the discrete points in the equivalent space of the laser to be calibrated. :

[0120] (13)

[0121] in For the first i After the first movement, the angle between the laser to be calibrated and the Z-axis can be estimated according to equation (13). The precision is on the order of micrometers, far below the accuracy required for laser calibration, and can be ignored. Therefore, it can be... t zi Ignoring this, equation (12) can be simplified to:

[0122] (14)

[0123] For the first i After the second move m The three-dimensional coordinates of the equivalent spatial discrete points after laser calibration are determined. Indicates the first i The z-coordinate value of the rotation center point of the translation stage 7 in the coordinate system of the display panel after the next movement, and , L This indicates the initial distance between the display panel 16 and the rotation center point of the translation stage 7 along the Z-axis. The initial two-dimensional coordinates of the rotation center point of the translation stage 7 in the coordinate system of the display panel.

[0124] Step 8: Based on the three-dimensional coordinates of the series of equivalent spatial discrete points of the laser to be calibrated obtained in Step 7, and the initial spot coordinates of the laser to be calibrated in the coordinate system of the display panel obtained in Step 3, the spatial straight line equation of the laser to be calibrated is obtained by fitting with the least squares method, thereby completing the spatial straight line calibration of the laser.

[0125] The calibration method of this embodiment solves the problem of calibration error caused by the stability error of the motion platform in the existing auxiliary device calibration method. It has the advantages of high accuracy and strong anti-interference ability. It can also realize the spatial linear calibration of multiple laser beams in the same coordinate system at the same time, and is suitable for long-distance and short-distance laser beam calibration.

[0126] Meanwhile, this embodiment addresses the issue of insufficient calibration accuracy caused by small-angle attitude and position errors of the translation stage 7 during laser beam calibration. It proposes a multi-laser beam collaborative correction mechanism: by constructing pose parameter solution equations using three or more reference lasers, and combining them with a spot coordinate correction algorithm, the measurement error of laser discrete point coordinates caused by the pose error of the translation stage 7 is separated, ultimately achieving high-precision calibration of the laser spatial straight line.

[0127] Example 2

[0128] like Figure 3 As shown, this embodiment provides another laser spatial line calibration system, including a movement module, a data acquisition module, a pose measurement module, and a data processing module. Figure 3 (Not shown in the image) This calibration system is mainly designed for situations where the axial error of the translation stage 7 is negligible or the calibration accuracy requirement is low, allowing for the direct acquisition of attitude angle parameters using a theodolite. β , α , γ (This skips the pose calculation step.)

[0129] The difference from Embodiment 1 is that the moving module in this embodiment only includes a translation stage 7; the translation stage 7 is an electrically controlled one-dimensional translation stage, used to perform one-dimensional linear motion during the calibration process. Similarly, the moving direction of the translation stage 7 is defined as the Z-axis, and the surface where the display panel 16 is located is the XOY plane. A mounting unit is installed on the translation stage 7 for mounting the laser to be calibrated.

[0130] The acquisition module is the same as that in Example 1, and will not be described again here.

[0131] It should be noted that the pose measurement module in this embodiment includes a first theodolite 12, a first reflecting mirror 8, a second theodolite 11, and a second reflecting mirror 9. The first reflecting mirror 8 is mounted on the mounting unit and can move synchronously with the laser to be calibrated, i.e., it maintains consistency with the attitude changes of the laser to be calibrated. The reflecting surface of the first reflecting mirror 8 is parallel to the XOY plane and is positioned away from the display panel 16. The first theodolite 12 is located on the reflected light path of the first reflecting mirror 8 and is used to measure the attitude change angles of the laser to be calibrated rotating around the X and Y axes, i.e., to realize the attitude change angles of the pitch and azimuth angles of the laser to be calibrated rotating around the X and Y axes.

[0132] The second reflector 9 is also mounted on the mounting unit and can move synchronously with the laser to be calibrated, that is, it keeps pace with the attitude change of the laser to be calibrated. The reflecting surface of the second reflector 9 is perpendicular to the XOY plane, and the second theodolite 11 is located in the reflected light path of the second reflector 9. It is used to measure the attitude change angle of the laser to be calibrated rotating around the Z-axis, that is, to realize the attitude change measurement of the tumble angle of the laser to be calibrated rotating around the Z-axis.

[0133] The data processing module is connected to the imaging detector 17, the first theodolite 12, and the second theodolite 11 respectively. It is used to receive the display panel image information containing the light spot, as well as the attitude change angle of the laser to be calibrated rotating around the X-axis, Y-axis, and Z-axis, and to calculate the spatial linear equation of the laser to be calibrated.

[0134] To track the position of the laser to be calibrated, the second theodolite 11 can be mounted on the guide rail 10 and can slide along the guide rail 10. Its sliding direction must be consistent with the movement direction of the translation stage 7.

[0135] Preferably, in this embodiment, the first reflecting mirror 8 and the second reflecting mirror 9 are integrated planar reference mirrors with orthogonal reflecting surfaces, thereby improving the calibration accuracy.

[0136] This embodiment utilizes the collected spatial discrete point coordinate data of the laser to be calibrated and the attitude data of the light source module directly collected by the theodolite, combined with the spot coordinate correction algorithm, to separate the measurement error of the laser discrete point coordinates caused by the attitude error of the translation stage 7, and finally fit the spatial linear equation of the laser to be calibrated.

[0137] The following describes another laser spatial line calibration method for the calibration system of this embodiment, including the following steps:

[0138] Step 1: Assemble the laser spatial linear calibration system described in this embodiment, and define the coordinate system formed by the XOY plane and the Z axis as the display panel coordinate system. Simultaneously, define the center point of the attitude change of the translation stage 7 relative to its theoretical position as its rotation center point, and record the initial two-dimensional coordinates of this rotation center point in the display panel coordinate system.

[0139] Step 2: Install the laser to be calibrated on the mounting unit so that the emitting end of the laser to be calibrated faces the receiving surface of the display panel 16.

[0140] Step 3: The image information of the display panel containing the laser spot to be calibrated is recorded by the imaging detector 17 and transmitted to the data processing module. Then, the initial spot coordinates of the laser to be calibrated in the coordinate system of the display panel are obtained by the data processing module.

[0141] Step 4: Move the translation stage 7 along the Z-axis once and record its movement distance. Then, following the method in Step 3, obtain the spot coordinates of the laser to be calibrated in the coordinate system of the display panel after the laser moves once. Then, obtain the three-dimensional coordinates of the equivalent spatial discrete point in the coordinate system of the display panel after the laser to be calibrated moves once. At the same time, measure the attitude change angle of the laser to be calibrated after it moves once using the first theodolite and the second theodolite.

[0142] Step 5: Move the laser several times according to the method in Step 4 to obtain the three-dimensional coordinates and attitude change angles of a series of equivalent spatial discrete points after each movement of the laser to be calibrated.

[0143] Step 6: Establish the discrete point coordinate correction equation, and substitute the three-dimensional coordinates and attitude change angles of the series of equivalent spatial discrete points after each movement of the laser to be calibrated, obtained in Step 4 and Step 5, into the discrete point coordinate correction equation to solve for the three-dimensional coordinates of the series of equivalent spatial discrete points after the laser to be calibrated is corrected.

[0144] The equation for correcting the coordinates of discrete points is as follows:

[0145]

[0146] The difference from Example 1 is that the discrete point coordinate correction equation ( β i , α i , γ i It can be obtained directly by measuring with the first and second theodolites, combined with known data. R ,neglect t ( t If the value is 0, the corresponding position information after laser calibration can be obtained. P mi .

[0147] Step 7: Based on the three-dimensional coordinates of a series of equivalent spatial discrete points after the laser to be calibrated is corrected, and the initial spot coordinates of the laser to be calibrated in the coordinate system of the display panel obtained in Step 3, the spatial straight line equation of the laser to be calibrated is obtained by fitting with the least squares method, thereby completing the spatial straight line calibration of the laser.

[0148] This embodiment addresses the need for rapid and simple calibration by using a first theodolite and a second theodolite to monitor the attitude, thereby separating the laser discrete point coordinate measurement error caused by the attitude error of the translation stage 7, effectively reducing the laser beam calibration error.

[0149] This invention enables high-precision acquisition, error correction, and spatial linear equation fitting of discrete points in multi-beam laser systems. It can effectively improve calibration accuracy and calibration efficiency of multi-beam systems and is applicable to scenarios such as industrial inspection, space positioning systems, aerospace docking, and robot positioning.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A laser spatial straight line calibration system for calibrating M laser beams in a single coordinate system, where M ≥ 1, characterized in that: It includes a movement module, a data acquisition module, a pose measurement module, and a data processing module; The moving module includes a translation stage (7) and N reference lasers, where N≥3; the translation stage (7) is an electrically controlled one-dimensional translation stage, used to perform one-dimensional linear motion during the calibration process, and the moving direction of the translation stage (7) is defined as the Z-axis; a mounting unit is installed on the translation stage (7) for mounting the reference lasers and the lasers to be calibrated; the reference lasers are used to emit reference lasers, and the beam direction of the reference lasers is parallel to the Z-axis; The acquisition module includes a display panel (16) and an imaging detector (17); the display panel (16) is a flat plate structure and is perpendicular to the Z-axis, used to receive the laser to be calibrated emitted by the laser to be calibrated and form a light spot, and the receiving surface of the display panel (16) is defined as the XOY plane; the imaging detector (17) is set close to the receiving surface of the display panel (16) and is used to acquire the display panel image information containing the light spot; The pose measurement module includes N spot position detectors that correspond one-to-one with the reference laser. The N spot position detectors are distributed at different positions at the emission end of the reference laser, and the detection target surface of each spot position detector is perpendicular to the Z-axis. They are used to measure the position information of the reference laser on the detection target surface of the corresponding spot position detector. The data processing module is connected to the imaging detector (17) and N spot position detectors respectively. It is used to receive the display panel image information containing the spot and the position information of the reference laser on the detection target surface of the corresponding spot position detector, and calculate the spatial straight line equation of the laser to be calibrated. The specific calculation method is as follows: using the collected spatial discrete point coordinate data of the laser to be calibrated and the spatial discrete point coordinate data of the reference laser, combined with the spot coordinate correction algorithm, the laser discrete point coordinate measurement error caused by the pose error of the translation stage (7) is separated, and finally the spatial straight line equation of the laser to be calibrated is obtained by fitting.

2. A laser spatial line calibration method, characterized in that, Includes the following steps: Step 1: Assemble the laser spatial linear calibration system as described in claim 1, and define the coordinate system formed by the XOY plane and the Z axis as the display panel coordinate system; Step 2: Install the laser to be calibrated on the mounting unit so that the emitting end of the laser to be calibrated faces the receiving surface of the display panel (16); at the same time, adjust the attitude of the mounting unit on the translation stage (7) so that the beam direction of each reference laser is parallel to the Z-axis. Step 3: Record the position information of each reference laser beam on its detection target surface through the corresponding spot position detector and transmit it to the data processing module; obtain the initial spot coordinates of each reference laser beam through the data processing module, and then obtain the initial straight line equation of the reference laser in the corresponding detector coordinate system; the detector coordinate system refers to the coordinate system corresponding to each spot position detector with the same XY coordinate components as the display panel coordinate system. Meanwhile, the image information of the display panel containing the laser spot to be calibrated is recorded by the imaging detector (17) and transmitted to the data processing module. The initial spot coordinates of the laser to be calibrated in the display panel coordinate system are then obtained by the data processing module. Step 4: Move the translation stage (7) along the Z-axis once and record its movement distance. Then, obtain the spot coordinates of the reference laser and the laser to be calibrated in the corresponding coordinate system according to the method in Step 3, so as to obtain the three-dimensional coordinates of the equivalent spatial discrete point in the corresponding coordinate system after the reference laser and the laser to be calibrated have moved once. Step 5: Move the laser several times according to the method in Step 4 to obtain the three-dimensional coordinates of a series of equivalent spatial discrete points in the corresponding coordinate system after each movement of the reference laser and the laser to be calibrated. Step 6: Based on the initial straight line equation obtained in Step 3, and the three-dimensional coordinates of the equivalent space discrete point after each movement of the reference laser obtained in Steps 4 and 5, construct the pose parameter solution equation, and further solve to obtain the pose change parameters of the translation stage (7) after each movement. Step 7: Establish the discrete point coordinate correction equation, and substitute the three-dimensional coordinates of the equivalent spatial discrete points after each movement of the laser to be calibrated obtained in Step 4 and Step 5, as well as the pose change parameters calculated in Step 6, into the discrete point coordinate correction equation to solve for the series of three-dimensional coordinates of the equivalent spatial discrete points after the laser to be calibrated is corrected. Step 8: Combining the three-dimensional coordinates of the series of equivalent spatial discrete points after the laser to be calibrated is corrected, and the initial spot coordinates of the laser to be calibrated in the coordinate system of the display panel obtained in Step 3, the spatial straight line equation of the laser to be calibrated is obtained by fitting with the least squares method, thereby completing the spatial straight line calibration of the laser.

3. The laser spatial line calibration method according to claim 2, characterized in that: Step 1 specifically involves assembling the laser spatial linear calibration system as described in claim 1, defining the center point of the attitude change of the translation stage (7) relative to the theoretical position as its rotation center point for attitude change, and recording the initial distance between the rotation center point along the Z-axis and the detection target surface of each spot position detector and the display panel (16), while also recording the initial two-dimensional coordinates of the rotation center point in the display panel coordinate system, and the position difference in the XY direction between the center of the detection target surface of each spot position detector and the origin of the display panel coordinate system. In step 3, the initial straight line equation is obtained using the following method: The initial spot coordinates of each reference laser beam on the detection target surface of the corresponding spot position detector are obtained by the data processing module. Then, combined with the position difference in the XY direction between the center of the detection target surface of each spot position detector and the origin of the display panel coordinate system recorded in step 1, N detector coordinate systems are established, and the initial straight line equation of the reference laser in the corresponding detector coordinate system is obtained.

4. The laser spatial line calibration method according to claim 3, characterized in that: In step 6, the equation for solving the pose parameters is: ； In the formula, and Let represent the spot coordinates of the k-th reference laser beam in the corresponding detector coordinate system after the i-th movement, where k = 1, 2, 3... N; and i represents the order of movement. and These represent the initial spot coordinates of the k-th reference laser beam in the corresponding detector coordinate system before the beam moves; This indicates the Z-coordinate component of the rotation center point of the translation stage (7) in the corresponding detector coordinate system and ,in, This represents the initial distance along the Z-axis between the rotation center point of the translation stage (7) and the detection target surface of the k-th spot position detector. This represents the total distance that the translation stage (7) moves relative to its initial position in the Z-axis direction after moving i times; The angle representing the attitude change of the translation stage (7) after it moves i times and rotates around the Y-axis; The angle representing the attitude change of the translation stage (7) after it moves i times and rotates around the X-axis; The angle representing the attitude change of the translation stage (7) after it moves i times and rotates around the Z-axis; and These represent the offsets relative to the theoretical positions in the X-axis and Y-axis directions after the translation stage (7) moves i times.

5. The laser spatial line calibration method according to claim 4, characterized in that: In step 7, the discrete point coordinate correction equation is: ； In the formula, This represents the three-dimensional coordinates of the equivalent spatial discrete point after the m-th laser beam to be calibrated and corrected following the i-th movement. and Let m and m represent the spot coordinates of the m-th laser beam to be calibrated in the coordinate system of the display panel after the i-th movement, where m = 1, 2, 3...M; This represents the z-coordinate of the rotation center point of the translation stage (7) in the display panel coordinate system after the i-th movement, and L represents the initial distance between the rotation center point of the display panel (16) and the translation stage (7) along the Z-axis; and These represent the initial two-dimensional coordinates of the rotation center point of the translation stage (7) in the coordinate system of the display panel.

6. A laser spatial line calibration system, characterized in that: It includes a movement module, a data acquisition module, a pose measurement module, and a data processing module; The moving module includes a translation stage (7); the translation stage (7) is an electrically controlled one-dimensional translation stage, used to perform one-dimensional linear motion during the calibration process, and the moving direction of the translation stage (7) is defined as the Z-axis; a mounting unit is installed on the translation stage (7) for mounting the laser to be calibrated; The acquisition module includes a display panel (16) and an imaging detector (17); the display panel (16) is a flat plate structure and is perpendicular to the Z-axis, used to receive the laser to be calibrated emitted by the laser to be calibrated and form a light spot, and the receiving surface of the display panel (16) is defined as the XOY plane; the imaging detector (17) is set close to the receiving surface of the display panel (16) and is used to acquire the display panel image information containing the light spot; The pose measurement module includes a first theodolite (12), a first reflector (8), a second theodolite (11), and a second reflector (9); the first reflector (8) is mounted on the mounting unit, and the reflecting surface of the first reflector (8) is parallel to the XOY plane and far away from the display panel (16). The first theodolite (12) is located on the reflected light path of the first reflector (8) and is used to measure the attitude change angle of the laser to be calibrated rotating around the X-axis and Y-axis. The second reflector (9) is mounted on the mounting unit, and the reflecting surface of the second reflector (9) is perpendicular to the XOY plane. The second theodolite (11) is located on the reflected light path of the second reflector (9) and is used to measure the attitude change angle of the laser to be calibrated rotating around the Z-axis. The data processing module is connected to the imaging detector (17), the first theodolite (12), and the second theodolite (11) respectively. It is used to receive the display panel image information containing the light spot, as well as the attitude change angle of the laser to be calibrated rotating around the X-axis, Y-axis, and Z-axis, and to calculate the spatial linear equation of the laser to be calibrated. The specific calculation method is as follows: using the collected spatial discrete point coordinate data of the laser to be calibrated and the attitude data of the light source module directly collected by the theodolite, combined with the light spot coordinate correction algorithm, the laser discrete point coordinate measurement error caused by the attitude error of the translation stage (7) is separated, and finally the spatial linear equation of the laser to be calibrated is fitted.

7. The laser spatial line calibration system according to claim 6, characterized in that: It also includes a guide rail (10), on which the second theodolite (11) is mounted and can slide along the guide rail (10), with its sliding direction consistent with the movement direction of the translation stage (7).

8. The laser spatial line calibration system according to claim 7, characterized in that: The first reflector (8) and the second reflector (9) are integrated planar reference mirrors with orthogonal reflecting surfaces.

9. A laser spatial line calibration method, characterized in that, Includes the following steps: Step 1: Assemble the laser spatial linear calibration system as described in claim 6, 7, or 8, and define the coordinate system formed by the XOY plane and the Z axis as the display panel coordinate system; Step 2: Install the laser to be calibrated on the mounting unit so that the emitting end of the laser to be calibrated faces the receiving surface of the display panel (16); Step 3: Record the display panel image information containing the laser spot to be calibrated through the imaging detector (17) and transmit it to the data processing module. Then, obtain the initial spot coordinates of the laser to be calibrated in the display panel coordinate system through the data processing module. Step 4: Move the translation stage (7) along the Z-axis once and record its movement distance. Then, following the method in Step 3, obtain the spot coordinates of the laser to be calibrated in the coordinate system of the display panel after the laser moves once. Then, obtain the three-dimensional coordinates of the equivalent spatial discrete point in the coordinate system of the display panel after the laser to be calibrated moves once. At the same time, measure the attitude change angle of the laser to be calibrated after it moves once using the first theodolite (12) and the second theodolite (11). Step 5: Move the laser several times according to the method in Step 4 to obtain the three-dimensional coordinates and attitude change angles of a series of equivalent spatial discrete points after each movement of the laser to be calibrated; Step 6: Establish the discrete point coordinate correction equation, and substitute the three-dimensional coordinates of the equivalent spatial discrete points and the corresponding attitude change angles of each movement of the laser to be calibrated obtained in Step 4 and Step 5 into the discrete point coordinate correction equation to solve for the three-dimensional coordinates of a series of equivalent spatial discrete points after the laser to be calibrated is corrected. Step 7: Combining the three-dimensional coordinates of the series of equivalent spatial discrete points after the laser to be calibrated is corrected, and the initial spot coordinates of the laser to be calibrated in the display panel coordinate system obtained in Step 3, the least squares method is used to fit the spatial straight line equation of the laser to be calibrated, thereby completing the spatial straight line calibration of the laser.

10. The laser spatial line calibration method according to claim 9, characterized in that: In step 6, the discrete point coordinate correction equation is: ； In the formula, Let m represent the three-dimensional coordinates of the equivalent spatial discrete point after the m-th laser beam to be calibrated following the i-th movement, where m = 1, 2, 3...M; and These represent the spot coordinates of the m-th laser beam to be calibrated in the coordinate system of the display panel after the i-th movement; This represents the z-coordinate of the rotation center point of the translation stage (7) in the display panel coordinate system after the i-th movement, and L represents the initial distance between the rotation center point of the display panel (16) and the translation stage (7) along the Z-axis; This represents the total distance that the translation stage (7) moves relative to its initial position in the Z-axis direction after moving i times; and These represent the initial two-dimensional coordinates of the rotation center point of the translation stage (7) in the display panel coordinate system; , , These represent the attitude change information measured by the first theodolite (12) and the second theodolite (11) after the i-th movement of the translation stage (7), respectively. The angle representing the attitude change of the translation stage (7) after it moves i times and rotates around the Y-axis; The angle representing the attitude change of the translation stage (7) after it moves i times and rotates around the X-axis; The angle represents the change in attitude of the translation stage (7) after it moves i times and rotates around the Z-axis.

Images