CN114638900A - Iterative calibration method and system for optical distortion and pose of laser scanning system - Google Patents

Iterative calibration method and system for optical distortion and pose of laser scanning system Download PDF

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CN114638900A
CN114638900A CN202210160122.1A CN202210160122A CN114638900A CN 114638900 A CN114638900 A CN 114638900A CN 202210160122 A CN202210160122 A CN 202210160122A CN 114638900 A CN114638900 A CN 114638900A
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laser scanning
iteration
matrix
coordinate system
scanning system
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李华兵
孙东明
林汇文
杨恺伦
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Hangzhou Lingxiang Technology Co ltd
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    • G06T7/80—Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/002—Measuring arrangements characterised by the use of optical techniques for measuring two or more coordinates
    • G01B11/005—Measuring arrangements characterised by the use of optical techniques for measuring two or more coordinates coordinate measuring machines
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
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Abstract

The invention belongs to the technical field of laser processing, and particularly relates to an iterative calibration method and system for optical distortion and pose of a laser scanning system. Method S1, generating N ideal points; s2, performing two-dimensional coordinate transformation on the ideal point; s3, punching N actual points on the target paper of the translation table; s4, calculating target coordinates of the N translation tables; s5, measuring the coordinates of the current target coordinate point in the camera coordinate system; s6, processing data by using the rotation matrix; s7, calculating and obtaining the transformed rotation matrix and a vector from the camera origin to the laser scanning system origin; s8, calculating to obtain a distortion coefficient matrix obtained by current iteration; s9, fusing the data obtained by the current iteration with the value of the previous iteration, and taking the fused value as the input value of the next iteration; and S10, repeating the steps S2 to S9 to obtain the final calibration result. The invention has the characteristics of convenient operation and high calibration precision.

Description

Iterative calibration method and system for optical distortion and pose of laser scanning system
Technical Field
The invention belongs to the technical field of laser processing, and particularly relates to an iterative calibration method and system for optical distortion and pose of a laser scanning system.
Background
In the laser processing industry, a set of laser scanning system is formed by matching a common galvanometer and a field lens, wherein the common galvanometer realizes light beam scanning, and the field lens realizes light beam focusing. Such a processing apparatus has a high scanning efficiency, and thus has a wide range of applications in laser marking, laser drilling, laser cutting, laser 3D printing, and the like. The ideal field lens is in accordance with the f-theta model, that is, when the vibrating lens deflects the light beam to form an angle theta with the optical axis of the field lens, the distance d between the focal point of the light beam passing through the field lens and the optical axis on the working surface is f x theta, that is, the deflection angle of the light beam is linearly related to the focal point position of the light beam. However, the field lens usually has large optical distortion, so that the imaging model of the field lens does not completely conform to the f-theta model, and therefore, the actual imaging model of the field lens must be calibrated, and the model is used for transforming the input coordinates, so that the distortion is corrected and the spot position accuracy is improved.
In some large-format and high-precision application scenarios, such as PCB laser drilling, there are usually several cameras fixed in position relative to the laser scanning system for target measurement. When the device works, the position of a target of a workpiece to be machined is measured through a camera, parameters of rotation, translation, stretching and the like of the workpiece on a machining platform are calculated, and then the galvanometer and the platform are driven to perform corresponding machining on the workpiece. Under such a processing flow, the relative translation between the laser scanning system and the camera, the relative translation and rotation between the laser scanning system and the platform must be accurately calibrated, otherwise, the processing precision is inevitably insufficient.
In practical applications, because the motion stroke of the processing platform is generally large and the precision is high, the coordinate system of the processing platform is often used as the basic coordinate system, and the rotation amount R of the laser scanning systemmIs given relative to the coordinate system of the machining platform; and because the target measurement is completed by a camera, the vector T from the coordinate origin of the camera to the coordinate origin of the laser scanning system under the coordinate system of the translation tablecmTo indicate laser scanning systemsThe translation amount is more convenient. Theoretically RmThe expression should be three-dimensional rotation relative to the translation stage coordinate system, but the effects brought about by rotation about the X and Y axes can be described as tangential distortion of the scanning system and can be incorporated in a distortion calibration, so that only rotation about the Z axis, i.e. in the XY plane, needs to be calibrated. In the same way, TcmTheoretically, the vector should also be a three-dimensional vector, but considering that the target measured by the camera and the processing target of the laser scanning system are on the same plane, the translation amount in the Z direction has no meaning, and therefore, the translation amount in the XY plane only needs to be calibrated. Therefore, the calibration of the laser scanning system is mainly to calibrate the distortion F of the system and the two-dimensional rotation R relative to the translation tablemAnd a two-dimensional vector T from the origin of the camera under the coordinate system of the translation table to the origin of the scanning systemcm。
However, the conventional calibration method is usually used for separately calibrating the distortion and the relative pose of the laser scanning system, which is not only inconvenient, but also cannot jointly optimize the distortion and pose parameters, and thus the final calibration effect is poor. In addition, because the uncalibrated laser scanning system often has distortion and a pose far away from an ideal condition, all parameters cannot be effectively estimated by single calibration, and although the condition can be improved by taking an average value by multiple times of calibration, the high-precision application is still insufficient.
Therefore, it is very important to design a more convenient and high-precision iterative calibration method and system for optical distortion and pose of a laser scanning system.
For example, chinese patent application No. CN202111227161.0 describes a high-precision calibration method and device for a laser processing system, which obtains an image according to a designed pattern for calibration of a vision system, and completes distortion calibration of a correction camera, i.e. obtains an image after distortion correction; then controlling a laser and a deflection lens in a galvanometer system, marking a specific galvanometer distortion calibration pattern on the marking paper, acquiring an image shot by a camera, and calculating to obtain a distortion value of the galvanometer system; and then controlling the laser and a deflection lens in the galvanometer, marking a coordinate system calibration pattern which passes through the distortion data processing module on the marking paper, acquiring an image shot by the camera, and calculating to obtain the corresponding relation between the image coordinate system and the galvanometer coordinate system. Although the distortion of the galvanometer system is automatically corrected through the vision system and the galvanometer distortion data processing module, the high-precision consistent marking of the galvanometer system in the whole marking work area is realized, and the calibration of the galvanometer system is simplified, the method has the defects that the distortion of the laser scanning system is singly calibrated, the distortion and pose parameters cannot be jointly optimized, and the final calibration effect is poor.
Disclosure of Invention
The invention provides an iterative calibration method and an iterative calibration system for optical distortion and relative pose of a laser scanning system, which are convenient to operate and high in precision, and aims to overcome the problems that the traditional calibration method is not convenient to separately calibrate the distortion and relative pose of the laser scanning system, and the final calibration effect is poor due to the fact that distortion and pose parameters cannot be jointly optimized in the prior art.
In order to achieve the purpose, the invention adopts the following technical scheme:
the iterative calibration method for the optical distortion and the pose of the laser scanning system comprises the following steps;
s1, generating N ideal points P under the laser scanning coordinate systemi＝(xi,yi)；i＝1,2,3,…,N；
S2, if the ideal point is to carry out the first iteration, let Pi′＝Pi(ii) a If not, performing two-dimensional coordinate transformation on the ideal point by using the distortion transformation coefficient matrix F obtained in the last iteration to obtain Pi′＝(xi′,yi′)；
S3, moving the translation stage to a preset position for fixing, and recording the coordinate (x) of the translation stage at the momentt0,yt0) And is combined with PiInputting the data into a galvanometer controller, and simultaneously starting laser to punch N actual points on target paper of a translation table;
s4, utilizing the rotation matrix R between the laser scanning system and the translation table coordinate system obtained in the last iterationmAnd center to center of cameraVector T of mirror centercmCalculating the target coordinates P of N translation stagesmi(ii) a If the iteration is performed for the first time, RmAnd TcmAssigning according to a preset ideal value;
s5, driving the translation stage to reach each target coordinate PmiAnd measuring the coordinate P of the current target coordinate point in the camera coordinate system by using the cameraci＝(xci,yci)；
S6, using the rotation matrix R of the camera coordinate system relative to the translation table coordinate system calibrated in advancecA 1 is to PciTransforming to the coordinate system of the translation table to obtain Pti', and to Pti' Debiasing to obtain Pti″；
S7, using Pi、Pti' and PtiConstructing parameter matrix, and calculating rotation matrix R of laser scanning system coordinate system relative to translation table coordinate system in current iterationm' and vector T from camera origin to laser scanning system origincm′；
S8, using Rm' and PtiConstructing a parameter matrix, and calculating to obtain a distortion coefficient matrix F' obtained by current iteration;
s9, obtaining R by iterationm′、Tcm'and F' are fused with the value of the previous iteration, and the fused value is used as the input value of the next iteration;
and S10, repeating the steps S2 to S9, and iterating for a preset number of times to obtain a final laser scanning system parameter calibration result.
Preferably, P in step S2i′＝(xi′,yi') is a polynomial fit, the specific formula is as follows: .
Figure BDA0003514191330000041
Wherein, FijRepresenting i rows and j columns in a distortion transformation coefficient matrix F; k is an integer, and the size of k is determined according to the order of the polynomial.
Preferably, P in step S4miThe calculation formula of (a) is as follows:
Pti＝Rm -1*Pi
Pmi＝Tcm+Pti+[xt0,yt0]T。
preferably, P in step S6ti' and Pti"is calculated as follows:
Figure BDA0003514191330000042
Figure BDA0003514191330000043
preferably, R in step S7mThe calculation of' is as follows:
by PiConstruction matrix
Figure BDA0003514191330000044
By Pti"construction matrix
Figure BDA0003514191330000045
Order to
Figure BDA0003514191330000046
Wherein B is-1A generalized inverse matrix that is matrix B; the rotation angle of the coordinate system of the laser scanning system relative to the coordinate system of the translation stage is obtained in the current iteration as
Figure BDA0003514191330000051
The corresponding rotation matrix is
Figure BDA0003514191330000052
Preferably, T in step S7cmThe calculation formula of' is as follows:
Figure BDA0003514191330000053
Figure BDA0003514191330000054
preferably, the calculation process of F' in step S8 is as follows:
order to
Figure BDA0003514191330000055
And constructs the matrix C, D as follows,
Figure BDA0003514191330000056
D＝[x0 y0 x1 y1 ... xN yN]T；
then F ═ C-1D)TIn which C is-1Is the generalized inverse of matrix C and z is the order of the polynomial.
Preferably, R is obtained by iteration in step S9m′、TcmThe process of fusing 'and F' with the values of the last iteration is as follows:
R′m、Tc′mand fusing with the value of the last iteration, wherein the specific formula is as follows:
Figure BDA0003514191330000057
wherein beta is1And beta2The value ranges are all 0-1;
f' is fused with the value of the last iteration, namely the fusion mode of F is as follows:
the ideal point P is obtained by using the continuous pair principle of F and F' according to the formulai＝(xi,yi) (ii) a i is 1,2,3, …, N is transformed twice;
Figure BDA0003514191330000058
Figure BDA0003514191330000061
then, the matrices C 'and D are constructed as follows, and the distortion coefficient matrix F ″, after fusion, is (C'-1D)T
Figure BDA0003514191330000062
D＝[x0 y0 x1 y1 ... xN yN]T；。
The invention also provides an iterative calibration system for optical distortion and pose of a laser scanning system, which comprises:
an ideal point generation module for generating N ideal points P under the laser scanning coordinate systemi＝(xi,yi)；i＝1,2,3,…,N；
The ideal point transformation module is used for carrying out first iteration and two-dimensional coordinate transformation on the ideal points;
a target coordinate calculation module for utilizing the rotation matrix R between the laser scanning system and the translation table coordinate system obtained by the last iterationmAnd the vector T from the center of the camera to the center of the galvanometercmCalculating the target coordinates P of N translation stagesmi；
A camera coordinate system measuring module for driving the translation stage to reach each target coordinate PmiAnd measuring the coordinate P of the current target coordinate point in the camera coordinate system by using the cameraci＝(xci,yci)；
A coordinate system transformation module for utilizing a rotation matrix R of the camera coordinate system relative to the translation table coordinate system calibrated in advancecA 1 is to PciTransforming to the coordinate system of the translation table to obtain Pti', and to Pti' Debiasing to obtain Pti″；
A data matrix fusion module for utilizing Pi、Pti' and PtiConstructing parameter matrix, and calculating rotation matrix R of laser scanning system coordinate system relative to translation table coordinate system in current iterationm' and vector T from camera origin to laser scanning system origincm'; by means of Rm' and PtiConstructing a parameter matrix, and calculating to obtain a distortion coefficient matrix F' obtained by current iteration; will iterate to obtain Rm′、Tcm'and F' are fused with the value of the last iteration, and the fused value is used as the input value of the next iteration.
Compared with the prior art, the invention has the beneficial effects that: (1) the invention has high calibration precision, and the invention adopts an iterative calibration method, so that the position of the point on the target paper can be gradually converged to be consistent with the ideal point coordinate along with the progress of the calibration iteration, thereby gradually reducing the estimation error of the rotation, translation and laser scanning system distortion, and effectively preventing the error of the prepositive calibration result from being amplified in the subsequent calibration because the values of the rotation, translation and laser scanning system distortion are synchronously updated instead of calibrating each variable one by one; (2) the method has high calibration reliability, the number of ideal points during calibration can be far larger than the parameter quantity to be solved, an overdetermined equation is constructed, and the least square solution is solved by utilizing a generalized inverse mode, so that the influence of errors can be effectively reduced; in addition, by adopting an iterative calibration method, the conditions that the distortion of the galvanometer is large and the parameter estimation is inaccurate during the first calibration can be avoided; (3) the parameter quantity used by the method is flexible in change, and the order of the distortion model and the number of ideal points can be increased or decreased by simply modifying a program according to the requirements of calibration precision and efficiency; (4) the invention has simple and convenient use, less human intervention and high automation degree, and is beneficial to reducing the labor cost and improving the debugging efficiency of the equipment in the process of producing the equipment in batch.
Drawings
FIG. 1 is a schematic view of a laser processing apparatus according to the present invention;
fig. 2 is a schematic diagram of ideal point distribution and one distribution of laser marking points in multiple iterations.
In the figure: the laser scanning system comprises a laser scanning system 1, a galvanometer 2, a field lens 3, a laser beam 4, a camera 5, a translation table 6, target paper 7 and a mark point 8.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention, the following description will explain the embodiments of the present invention with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.
Example 1:
as shown in FIG. 1, the iterative calibration method for the optical distortion and pose of the laser scanning system comprises the following steps
Step S1, generating N ideal points under a laser scanning system coordinate system, wherein the unit of the ideal points should be an actual length unit, such as um, mm and the like, and in addition, the N ideal points are required to be not overlapped and not on the same straight line, and N can be 25-121 according to actual requirements; as shown in fig. 2, in this embodiment, N is 81, and the distribution of ideal points is a matrix of 9 rows and 9 columns;
step S2, distortion transformation order is predetermined, and the order can be 1-5, preferably 3; in this embodiment, taking 3 rd order as an example, the distortion transformation coefficient matrix F obtained from the last iteration is utilized to perform two-dimensional coordinate transformation on an ideal point according to the following formula to obtain Pi′＝(xi′,yi') to a host; if the iteration is performed for the first time, P can be orderedi′＝Pi。
Figure BDA0003514191330000081
Step S3, as shown in fig. 1, the target paper 7 is placed on the translation stage 6, and the target paper is moved to a suitable position below the laser scanning system 1, and the coordinates (x) of the translation stage 6 at this time are recorded with an arbitrary fixed reference point as the origint0,yt0) (ii) a Turning on the laser beam 4 to emit Pi' ofThe coordinates are input into a controller of the galvanometer 2, and a galvanometer deflected light beam is focused on the galvanometer deflected light beam through the field lens 3 to hit N mark points 8.
Step S4, utilizing the rotation matrix R between the laser scanning system and the translation table coordinate system obtained in the last iterationmN ideal points P under the galvanometer coordinate systemiCoordinate transformation to the translation stage coordinate system, i.e. Pti＝Rm -1*Pi(ii) a If the iteration is carried out for the first time, an initial rotation matrix R can be constructed according to the design angle (such as 0 degree and 90 degrees) between the actual galvanometer and the translation stagem。
Step S5, using the vector T from the camera 5 to the origin of the coordinate system of the laser scanning system obtained in the last iterationcmCalculating the coordinates P of the translation stage when measuring N points by the camerami＝Tcm+Pti+[xt0,yt0]TAnd driving the translation stage to each target coordinate PmiWhile the camera measures the coordinates P of the point in the camera coordinate systemci＝(xci,yci) (ii) a If the iteration is carried out for the first time, the translation stage can be manually driven to enable N points to appear in the camera visual field one by one and measure Pci。
Step S6, utilizing the rotation matrix R of the camera coordinate system relative to the translation table coordinate system which is calibrated in advancecP measured under the camera coordinate SystemciAnd transforming the coordinate system of the translation stage according to the following expression:
Figure BDA0003514191330000082
will Pti' Debiasing, i.e.
Figure BDA0003514191330000091
Step S7, constructing the matrix A, B according to the following formula
Figure BDA0003514191330000092
Wherein B is-1Referring to the generalized inverse moment of matrix B, the generalized inverse moment is solved in the iteration of the roundThe rotation angle of the coordinate system of the laser scanning system relative to the coordinate system of the translation table is obtained as
Figure BDA0003514191330000093
Corresponding rotation matrix is
Figure BDA0003514191330000094
Figure BDA0003514191330000095
Constructing matrix H according to the following formula, that is, the vector from the center of the camera to the center of the laser scanning system can be obtained in the iteration
Figure BDA0003514191330000096
Figure BDA0003514191330000097
Step S8, let
Figure BDA0003514191330000098
Constructing a matrix C, D; the distortion coefficient matrix F' obtained in the current iteration is equal to (C)-1D)T；
Figure BDA0003514191330000099
D＝[x0 y0 x1 y1 ... xn yn]T；。
Step S9, R obtained from the current iteration ism′、Tcm' the value R input according to the following formula and the current iterationm、TcmFusing, and taking the fused value as the input of the next iteration; wherein beta is1And beta2The value range is 0-1, and the value can be fixed or changed along with the iteration number. Beta at first iteration1And beta2Preferably 0, thereafterThe iteration is preferably 0.1-0.2, and the specific formula is as follows:
Figure BDA0003514191330000101
and F' obtained by the current iteration is fused with the value F input by the current iteration according to the following formula, and the fused value is used as the input value of the next iteration.
The ideal point P is obtained by using the continuous pair principle of F and F' according to the formulai＝(xi,yi) (ii) a i is 1,2,3, …, N is transformed twice;
Figure BDA0003514191330000102
Figure BDA0003514191330000103
the matrices C 'and D are constructed as follows, and the fused distortion coefficient matrix F ″ - (C ″)'-1D)T；
Figure BDA0003514191330000104
D＝[x0 y0 x1 y1 ... xN yN]T；。
Repeating the steps S2 to S9 to complete one iteration, as shown in fig. 2, as the calibration iteration proceeds, the error between the mark point actually printed by the laser scanning system and the ideal point will gradually converge, the convergence rate will gradually decrease, and the iteration number may be determined according to the distortion severity of the scene and the actually required scanning accuracy, and may be selected 2-5 times, preferably 3 times. After iteration for a preset number of times, obtaining a final laser scanning system parameter calibration result, namely a final output rotation matrix R of the laser scanning system relative to a translation table coordinate systemmThe vector T from the camera origin to the laser scanning system origincmAnd a laser scanning system distortion transformation coefficient matrix F.
The invention also provides an iterative calibration system for optical distortion and pose of a laser scanning system, which comprises:
an ideal point generating module for generating N ideal points P under the laser scanning coordinate systemi＝(xi,yi)；i＝1,2,3,…,N；
The ideal point transformation module is used for carrying out first iteration and two-dimensional coordinate transformation on the ideal points;
a target coordinate calculation module for utilizing the rotation matrix R between the laser scanning system and the translation table coordinate system obtained by the last iterationmAnd the vector T from the center of the camera to the center of the galvanometercmCalculating the target coordinates P of N translation stagesmi；
A camera coordinate system measuring module for driving the translation stage to reach each target coordinate PmiAnd measuring the coordinate P of the current target coordinate point in the camera coordinate system by using the cameraci＝(xci,yci)；
A coordinate system transformation module for utilizing a rotation matrix R of the camera coordinate system relative to the translation table coordinate system calibrated in advancecA 1 is to PciTransforming to the coordinate system of the translation table to obtain Pti' and to Pti' Debiasing to obtain Pti″；
A data matrix fusion module for utilizing Pi、Pti' and PtiConstructing parameter matrix, and calculating rotation matrix R of laser scanning system coordinate system relative to translation table coordinate system in current iterationm' and vector T from camera origin to laser scanning system origincm'; by means of Rm' and PtiConstructing a parameter matrix, and calculating to obtain a distortion coefficient matrix F' obtained by current iteration; will iterate to get Rm′、Tcm'and F' are fused with the value of the previous iteration, and the fused value is used as the input value of the next iteration.
The method jointly optimizes the distortion and pose parameters, so that the final calibration effect is improved, and the calibration precision is improved by adopting a mode of calibrating and averaging for multiple times; the technical scheme of the invention has the characteristics of convenient operation and high calibration precision.
The foregoing has outlined rather broadly the preferred embodiments and principles of the present invention and it will be appreciated that those skilled in the art may devise variations of the present invention that are within the spirit and scope of the appended claims.

Claims (9)

1. The iterative calibration method for the optical distortion and the pose of the laser scanning system is characterized by comprising the following steps;
s1, generating N ideal points P under the laser scanning coordinate systemi＝(xi,yi)；i＝1,2,3,…,N；
S2, if the ideal point is to carry out the first iteration, let Pi′＝Pi(ii) a If not, performing two-dimensional coordinate transformation on the ideal point by using the distortion transformation coefficient matrix F obtained in the last iteration to obtain Pi′＝(xi′,yi′)；
S3, moving the translation stage to a preset position for fixing, and recording the coordinate (x) of the translation stage at the momentt0,yt0) And is combined with PiInputting the data into a galvanometer controller, and simultaneously starting laser to punch N actual points on target paper of a translation table;
s4, utilizing the rotation matrix R between the laser scanning system and the translation table coordinate system obtained in the last iterationmAnd the vector T from the center of the camera to the center of the galvanometercmCalculating the target coordinates P of N translation stagesmi(ii) a If the iteration is performed for the first time, RmAnd TcmAssigning according to a preset ideal value;
s5, driving the translation stage to reach each target coordinate PmiAnd measuring the coordinate P of the current target coordinate point in the camera coordinate system by using the cameraci＝(xci,yci)；
S6, using the rotation matrix R of the camera coordinate system relative to the translation table coordinate system calibrated in advancecFrom P to PciTransforming to the coordinate system of the translation table to obtain Pti', and to Pti' Debiasing to obtain Pti″；
S7, using Pi、Pti' and PtiConstructing parameter matrix, and calculating rotation matrix R of laser scanning system coordinate system relative to translation table coordinate system in current iterationm' and vector T from camera origin to laser scanning system origincm′；
S8, using Rm' and PtiConstructing a parameter matrix, and calculating to obtain a distortion coefficient matrix F' obtained by current iteration;
s9, obtaining R through iterationm′、Tcm'and F' are fused with the value of the previous iteration, and the fused value is used as the input value of the next iteration;
and S10, repeating the steps S2 to S9, and iterating for a preset number of times to obtain a final laser scanning system parameter calibration result.
2. The iterative calibration method for optical distortion and pose of laser scanning system according to claim 1, wherein P in step S2i′＝(xi′,yi') is a polynomial fit, the specific formula is as follows: .
Figure FDA0003514191320000021
Wherein, FijRepresenting i rows and j columns in a distortion transformation coefficient matrix F; k is an integer, and the size of k is determined according to the order of the polynomial.
3. The iterative calibration method for optical distortion and pose of laser scanning system according to claim 1, wherein P in step S4miThe calculation formula of (a) is as follows:
Pti＝Rm -1*Pi
Pmi＝Tcm+Pti+[xt0,yt0]T。
4. the iterative calibration method for optical distortion and pose of laser scanning system according to claim 1, wherein P in step S6ti' and Pti"is calculated as follows:
Figure FDA0003514191320000022
Figure FDA0003514191320000023
5. the iterative calibration method for optical distortion and pose of laser scanning system according to claim 1, wherein R in step S7mThe calculation of' is as follows:
by PiConstruction matrix
Figure FDA0003514191320000024
By Pti"construction matrix
Figure FDA0003514191320000025
Order to
Figure FDA0003514191320000026
Wherein B is-1A generalized inverse matrix that is matrix B; the rotation angle of the coordinate system of the laser scanning system relative to the coordinate system of the translation stage is obtained in the current iteration as
Figure FDA0003514191320000031
The corresponding rotation matrix is
Figure FDA0003514191320000032
6. The iterative calibration method for optical distortion and pose of laser scanning system according to claim 5, wherein T in step S7cmThe calculation formula of' is as follows:
Figure FDA0003514191320000033
Figure FDA0003514191320000034
7. the iterative calibration method for optical distortion and pose of laser scanning system according to claim 1, wherein the calculation process of F' in step S8 is as follows:
order to
Figure FDA0003514191320000035
And constructs the matrix C, D as follows,
Figure FDA0003514191320000036
D＝[x0 y0 x1 y1...xN yN]T；
then F ═ C-1D)TIn which C is-1Is the generalized inverse of matrix C and z is the order of the polynomial.
8. The iterative calibration method for optical distortion and pose of laser scanning system according to claim 7, wherein R is obtained by iteration in step S9m′、TcmThe process of fusing 'and F' with the values of the last iteration is as follows:
R′m、T′cmand the last time of overlappingThe generation values are fused, and the specific formula is as follows:
Figure FDA0003514191320000037
wherein beta is1And beta2The value ranges are all 0-1;
f' is fused with the value of the last iteration, namely the fusion mode of F is as follows:
the ideal point P is obtained by using the continuous pair principle of F and F' according to the formulai＝(xi,yi) (ii) a Converting by 1,2,3, …, N twice;
Figure FDA0003514191320000041
Figure FDA0003514191320000042
the matrices C 'and D are constructed as follows, and the distortion coefficient matrix F ″ (C ″) after fusion is then constructed'-1D)T
Figure FDA0003514191320000043
D＝[x0 y0 x1 y1...xN yN]T；。
9. An iterative calibration system for optical distortion and pose of a laser scanning system, comprising:
an ideal point generation module for generating N ideal points P under the laser scanning coordinate systemi＝(xi,yi)；i＝1,2,3,…,N；
The ideal point transformation module is used for carrying out first iteration and two-dimensional coordinate transformation on the ideal points;
a target coordinate calculation module for utilizing the rotation matrix R between the laser scanning system and the translation table coordinate system obtained by the last iterationmAnd the vector T from the center of the camera to the center of the galvanometercmCalculating the target coordinates P of N translation stagesmi；
A camera coordinate system measuring module for driving the translation stage to reach each target coordinate PmiAnd measuring the coordinate P of the current target coordinate point in the camera coordinate system by using the cameraci＝(xci,yci)；
A coordinate system transformation module for utilizing a rotation matrix R of the camera coordinate system relative to the translation table coordinate system calibrated in advancecA 1 is to PciTransforming to the coordinate system of the translation table to obtain Pti' and to Pti' Debiasing to obtain Pti″；
A data matrix fusion module for utilizing Pi、Pti' and PtiConstructing parameter matrix, and calculating rotation matrix R of laser scanning system coordinate system relative to translation table coordinate system in current iterationm' and vector T from camera origin to laser scanning system origincm'; by means of Rm' and PtiConstructing a parameter matrix, and calculating to obtain a distortion coefficient matrix F' obtained by current iteration; will iterate to obtain Rm′、Tcm'and F' are fused with the value of the previous iteration, and the fused value is used as the input value of the next iteration.
CN202210160122.1A 2022-02-22 2022-02-22 Iterative calibration method and system for optical distortion and pose of laser scanning system Pending CN114638900A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115546016A (en) * 2022-11-26 2022-12-30 深圳市鹰眼在线电子科技有限公司 Method for acquiring and processing 2D (two-dimensional) and 3D (three-dimensional) images of PCB (printed Circuit Board) and related device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115546016A (en) * 2022-11-26 2022-12-30 深圳市鹰眼在线电子科技有限公司 Method for acquiring and processing 2D (two-dimensional) and 3D (three-dimensional) images of PCB (printed Circuit Board) and related device

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