CN117372547A - Coaxial vision correction method, device and equipment - Google Patents
Coaxial vision correction method, device and equipment Download PDFInfo
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Abstract
The application relates to the technical field of laser marking, and provides a coaxial vision correction method, a device and equipment, wherein the method comprises the following steps: acquiring a laser calibration file of the calibration system for image distortion, and verifying whether the laser calibration file meets a first preset precision; if the first preset precision is met, controlling to perform local calibration on the laser galvanometer and the CCD camera, obtaining a local calibration mapping relation, and verifying whether the local calibration mapping relation meets the second preset precision; and if the local calibration mode meets the second preset precision, controlling to perform global calibration on the laser galvanometer and the CCD camera to obtain a global calibration model, and verifying whether the global calibration model meets the third preset precision. According to the method, the problem that in the existing laser coaxial vision, because of chromatic aberration between the wavelength of the laser light source and the wavelength of the illumination light source, positioning errors exist in the process of sharing one calibration during multi-position deflection photographing positioning can be effectively solved.
Description
Technical Field
The application relates to the technical field of laser marking, in particular to a coaxial vision correction method, a coaxial vision correction device and coaxial vision correction equipment.
Background
In recent years, a machine vision positioning system has been widely applied to the industrial field, and in laser equipment, the machine vision positioning is particularly important, and is an indispensable function for laser welding, laser cutting, and an important means for greatly improving the working precision of the equipment and realizing precision machining. In order to improve the precision of machine vision in laser equipment, a coupling lens is used for coupling a laser and a visual light path together at the front end of a vibrating mirror, so that coaxial vision positioning is realized. In general, the coaxial visual positioning system of a laser device consists of the following parts: laser galvanometer, laser focusing field lens, coupling lens, CCD industrial camera, industrial lens, illumination light source, industrial computer, software algorithm platform. In the prior art, along with the improvement of processing efficiency or the complex structure of a welded product, the vibration mirror often does not only photograph and position at the center of the vibration mirror, but also positions a plurality of mark points through deflection of the vibration mirror to a plurality of areas for processing for a plurality of times. Since the field lens focus lens has field curvature, the refractive index of the edge is not consistent with the refractive index of the center. In the laser control software, the box is calibrated to reduce the effect of field curvature. However, the illumination light source of the CCD is also affected by field curvature, the laser wavelength is greatly different from the wavelength of the illumination light source of the CCD, the parameters of the calibration box cannot be used in the calibration of the CCD, aiming at the problems, in the prior art, 9 (more than 3) small circles are engraved on each photographing point by laser, the positions of the circles are visually identified, and the camera image coordinates and the laser galvanometer coordinates are bound through a visual calibration algorithm.
Disclosure of Invention
In view of this, the embodiments of the present application provide a coaxial vision correction method, apparatus, and device, which can effectively overcome the problem that in the existing laser coaxial vision, because there is a chromatic aberration between the wavelength of the laser light source and the wavelength of the illumination light source, there is a positioning error when sharing one calibration during multi-position deflection photographing positioning.
In a first aspect, an embodiment of the present application provides a coaxial vision correction method, where the method is applied to a coaxial vision positioning system of a laser device, and the coaxial vision positioning system of the laser marking device includes: the method comprises the following steps of:
acquiring a laser calibration file of a calibration system for image distortion, and verifying whether the laser calibration file meets a first preset precision;
if the first preset precision is met, controlling to perform local calibration on the laser galvanometer and the CCD camera, obtaining a local calibration mapping relation, and verifying whether the local calibration mapping relation meets the second preset precision;
and if the local calibration meets the second preset precision, controlling to perform global calibration on the laser galvanometer and the CCD camera to obtain a global calibration model, and verifying whether the global calibration model meets the third preset precision.
In some embodiments, the calibration system is coupled to the laser marking device;
the laser calibration file for image distortion of the acquisition calibration system comprises:
setting correction chart file parameters through a calibration system, and controlling the laser marking equipment to carry out light-emitting carving on nine-point correction chart files according to the correction chart file parameters;
and measuring the coordinates of the remaining points of the nine-point correction chart file by taking the central point of the nine-point correction chart file as the central coordinate, inputting the coordinates of the nine points of the nine-point correction chart file into the calibration system and generating the laser calibration file.
In some embodiments, the verifying whether the laser calibration file meets a first preset precision comprises:
drawing a test shape through marking software and engraving the test shape on marking paper;
and measuring the actual size of the test shape drawn on the calibration paper, comparing the actual size with the drawing size of the marking software, and if the deviation of any one edge is larger than a first preset deviation, failing to meet the first preset precision of the laser calibration file.
In some embodiments, the controlling performs local calibration on the laser galvanometer and the CCD camera to obtain a local calibration mapping relationship, including:
controlling marking software connected with the laser marking equipment to draw a first nine-point image file, and recording first galvanometer coordinates of nine points in the first nine-point image file; the length and width of the first nine-point image file are smaller than the length and width of the field of view of the CCD camera, and the center of the first nine-point image file is the origin of the laser galvanometer coordinate system;
controlling the laser marking equipment to engrave the first nine-point image on the calibration paper to form a first nine-point image;
controlling the CCD camera to photograph the first nine-point image and identifying first image coordinates of nine points in the first nine-point image;
and obtaining a local calibration mapping relation through the first galvanometer coordinate and the first image coordinate.
In some embodiments, the obtaining the local calibration mapping relationship through the first galvanometer coordinate and the first image coordinate includes:
a translation transformation matrix is adopted for the first image coordinate to obtain a transformed coordinate;
wherein, the translation transformation matrix formula is:
obtaining transformed coordinates by adopting a scaling transformation matrix for the first image coordinates;
the scaling transformation matrix formula is as follows:
a rotation conversion matrix is adopted for the first image coordinate to obtain a converted coordinate;
the rotation conversion matrix formula is as follows:
obtaining transformed coordinates by adopting a miscut transformation matrix for the first image coordinates;
wherein, the formula of the miscut transformation matrix is:
the transformation matrix is combined according to the formula 1, the formula 2, the formula 3 and the formula 4:
in the formula, (X, Y) is a first image coordinate, (u, v) is a transformed coordinate, a represents a translation length along an X-axis direction, b represents a translation length along a Y-axis direction, s1 represents a scaling in the X-axis direction, s2 represents a scaling in the Y-axis direction, θ represents a rotation angle, α1 represents an X-axis direction miscut angle, and α2 represents a Y-axis direction miscut angle;
substituting the first galvanometer coordinate and the first image coordinate into a formula 5, and combining a least square method to obtain a value of the unknown number A, B, C, D, E, F; wherein the first galvanometer coordinate is substituted into (u, v) in equation 5, and the first image coordinate is substituted into (x, y) in equation 5;
obtaining a mapping relation between the first image coordinate and the first galvanometer coordinate according to a formula 5 and the value of the unknown number A, B, C, D, E, F;
wherein, the mapping relation is formula 6:
u＝Ax+By+C
v＝Dx+Ey+F。
in some embodiments, the verifying whether the local calibration mapping satisfies a second preset precision includes:
drawing a point Q in the field of view of the CCD camera through the marking software and engraving the point Q on the marking paper to be marked as a first verification point; wherein the sitting at point Q is marked (x 0, y 0);
photographing and identifying image coordinates (x, y) of the first verification point by the CCD camera;
calculating according to the image coordinates (x, y) of the first verification point and a formula 6 to obtain verification galvanometer coordinates P (x 1, y 1);
and respectively comparing the coordinate (X0, Y0) of the point Q with the verification galvanometer coordinate P (X1, Y1) in the X-axis and Y-axis directions, and if the deviation of any direction is larger than a second preset deviation, the local calibration mapping relation does not meet the second preset precision.
In some embodiments, the controlling performs global calibration on the laser galvanometer and the CCD camera to obtain a global calibration model, including:
controlling marking software connected with the laser marking equipment to draw a second nine-point image file, and engraving the second nine-point image file on the calibration plate to form a second nine-point image; wherein the length and width of the second nine-point diagram file are 5mm-10mm larger than the length and width of the vibrating mirror breadth respectively;
identifying second image coordinates of the second nine-point image through the deflection of the vibrating mirror;
substituting the second image coordinates into the formula 6 respectively to obtain the coordinates of the deflection mirror;
summing the coordinate of the deflection mirror with the coordinate R (s, t) of the mirror at the photographing position, and calculating the global coordinate of the mirror at nine points;
obtaining a global calibration model according to the vibrating mirror global coordinate, the second image coordinate and the formula 5;
the global calibration model is formula 7:
o＝Hz+Iw+J
p＝Kz+Lw+M
wherein (z, w) is (u, v) in the formula 6; (o, p) is the galvanometer global coordinate.
In some embodiments, the verifying whether the global calibration model meets a third preset precision comprises:
drawing a point R within the range of 5mm-10mm larger than the vibrating mirror breadth by using the marking software, and carving the point R on the calibration paper to serve as a second verification point; wherein the sitting at point R is marked (x 1, y 1);
photographing and identifying image coordinates (x 2, y 2) of the second verification point by the CCD camera;
calculating according to the image coordinates (x 2, y 2) of the second verification point and a formula 7 to obtain a verification global T (x 3, y 3);
and respectively comparing the coordinates (X1, Y1) of the point R with the verification global coordinates T (X3, Y3) in the X-axis and Y-axis directions, wherein if any direction deviation is larger than a third preset deviation, the global calibration model does not meet the third preset precision.
In a second aspect, an embodiment of the present application provides a coaxial vision correction device, where the device is applied to a coaxial vision positioning system of a laser device, and the coaxial vision positioning system of the laser marking device includes: laser galvanometer, laser focus field lens, CCD camera, illumination light source, industrial control device, the device includes:
the first calibration module is used for acquiring a laser calibration file of the calibration system for image distortion and verifying whether the laser calibration file meets a first preset precision.
And the second calibration module is used for controlling the laser galvanometer and the CCD camera to be locally calibrated if the first preset precision is met, obtaining a local calibration mapping relation and verifying whether the local calibration mapping relation meets the second preset precision.
And the third calibration module is used for controlling the laser galvanometer and the CCD camera to perform global calibration if the local calibration meets the second preset precision, obtaining a global calibration model and verifying whether the global calibration model meets the third preset precision.
In a third aspect, embodiments of the present application provide a laser marking apparatus, where the laser marking apparatus includes a processor and a memory, where the memory stores a computer program, and the processor is configured to execute the computer program to implement the above-mentioned coaxial vision correction method.
The embodiment of the application has the following beneficial effects:
the method and the device calibrate the image distortion through galvanometer scanning; locally calibrating a camera coordinate system and a galvanometer coordinate system, and calibrating the relationship between the two coordinate systems in a small range according to the galvanometer after the calibration distortion; and then, performing global calibration through a camera coordinate system and a galvanometer coordinate system, and using a local calibration result to complete all calibration, so as to realize pixel coordinate conversion Cheng Zhenjing coordinates of a photographing result in a galvanometer scanning range to guide a laser working position. The method overcomes the defect that in the existing laser coaxial vision, because the wavelength of the laser light source and the wavelength of the illumination light source have chromatic aberration, the positioning error exists when the positioning is performed by sharing one calibration during multi-position deflection photographing.
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In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 shows a schematic flow chart of a coaxial vision correction method according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a correction software input profile parameter according to an embodiment of the present application;
FIG. 3 shows a schematic diagram of a nine-point chart drawn by marking software in an embodiment of the present application;
fig. 4 shows a schematic structural diagram of the coaxial vision correction device according to the embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments.
The components of the embodiments of the present application, which are generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, as provided in the accompanying drawings, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, are intended to be within the scope of the present application.
In the following, the terms "comprises", "comprising", "having" and their cognate terms may be used in various embodiments of the present application are intended only to refer to a particular feature, number, step, operation, element, component, or combination of the foregoing, and should not be interpreted as first excluding the existence of or increasing the likelihood of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of this application belong. The terms (such as those defined in commonly used dictionaries) will be interpreted as having a meaning that is identical to the meaning of the context in the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in connection with the various embodiments.
Some embodiments of the present application are described in detail below with reference to the accompanying drawings. The embodiments described below and features of the embodiments may be combined with each other without conflict.
The on-axis vision correction method is described below in connection with some specific embodiments.
Fig. 1 shows a schematic flow chart of a coaxial vision correction method according to an embodiment of the present application.
The coaxial vision correction method is applied to a coaxial vision positioning system of a laser device, and the coaxial vision positioning system of the laser marking device comprises the following components: the device comprises a laser vibrating mirror, a laser focusing field lens, a CCD camera, an illumination light source and an industrial control device.
The on-axis vision correction method exemplarily comprises the steps of:
s10, acquiring a laser calibration file of the calibration system for image distortion, and verifying whether the laser calibration file meets a first preset precision.
The coaxial vision module is installed on the laser marking equipment before the method is applied.
Setting correction chart file parameters through a calibration system, and controlling the laser marking equipment to carry out light-emitting engraving on nine-point correction chart files according to the correction chart file parameters; wherein the calibration system is connected with the laser marking device; and measuring the coordinates of the remaining points of the nine-point correction chart file by taking the central point of the nine-point correction chart file as the central coordinate, inputting the coordinates of the nine points of the nine-point correction chart file into the calibration system and generating the laser calibration file.
As shown in FIG. 2, the calibration system in the application adopts the gold orange correction software, calization wizard, usually selects 2DXY correction and sets corresponding correction chart file parameters, places calibration paper at the laser focus, performs light-emitting carving on the laser control software, uses the nine-point spacing of the actual light-emitting carving of the two-dimensional measuring instrument, and inputs the nine-point spacing into the software to generate a laser calibration file.
Further, the verifying whether the laser calibration file meets a first preset precision includes:
drawing a test shape through marking software and engraving the test shape on marking paper; for ease of later measurement comparison, the test shape is typically rectangular or square; wherein, marking software can select by oneself.
And measuring the actual size of the test shape drawn on the calibration paper, comparing the actual size with the drawing size of the marking software, and if the deviation of any one edge is larger than a first preset deviation, failing to meet the first preset precision of the laser calibration file. Specifically, a secondary measuring instrument is used for measuring the test shape engraved on the calibration paper, the shape of each side needs to be measured, if the test shape is rectangular, the length and the width of the rectangle are measured, then the measured actual size is compared with the drawing size of the marking software, if the length of the rectangle is 100mm, the length of the rectangle after actual measurement engraving is 99.95mm, the deviation is 0.05, the first preset deviation is usually set to be 0.01, if the deviation is 0.05, the first preset precision is not met, the calibration is needed again, and the first preset deviation is known to be met.
If the laser calibration file is verified to meet the first preset precision in the step S10, the step S20 is executed to control the local calibration of the laser galvanometer and the CCD camera, obtain a local calibration mapping relationship, and verify whether the local calibration mapping relationship meets the second preset precision.
In step S20, the controlling performs local calibration on the laser galvanometer and the CCD camera to obtain a local calibration mapping relationship, including:
if the marking software uses EzCad3, as shown in fig. 3, the marking software connected with the laser marking device is controlled to draw a first nine-point diagram file, and the first galvanometer coordinates of nine points in the first nine-point diagram file are recorded. The length and width of the first nine-point image file are smaller than the length and width of the field of view of the CCD camera, and the center of the first nine-point image file is the origin of the laser galvanometer coordinate system.
And controlling the laser marking equipment to engrave the first nine-point image on the calibration paper to form a first nine-point image, and returning the vibrating mirror to the original point after engraving the nine points on the calibration paper.
Controlling the CCD camera to photograph the first nine-point image and identifying first image coordinates of nine points in the first nine-point image; after the camera photographs the first nine-point image on the calibration paper, the first image coordinates of nine points in the first nine-point image can be identified through an Opencv operator Houghcircuits.
And obtaining a local calibration mapping relation through the first galvanometer coordinate and the first image coordinate.
Specifically, a translation transformation matrix is adopted for the first image coordinate (x, y) to obtain a transformed coordinate (u, v);
wherein, the translation transformation matrix formula is:
obtaining transformed coordinates by adopting a scaling transformation matrix for the first image coordinates;
the scaling transformation matrix formula is as follows:
a rotation conversion matrix is adopted for the first image coordinate to obtain a converted coordinate;
the rotation conversion matrix formula is as follows:
obtaining transformed coordinates by adopting a miscut transformation matrix for the first image coordinates;
wherein, the formula of the miscut transformation matrix is:
the transformation matrix is combined according to the formula 1, the formula 2, the formula 3 and the formula 4:
i.e.
Equation 5 is obtained:
in the formula, (X, Y) is a first image coordinate, (u, v) is a transformed coordinate, a represents a translation length along an X-axis direction, b represents a translation length along a Y-axis direction, s1 represents a scaling in the X-axis direction, s2 represents a scaling in the Y-axis direction, θ represents a rotation angle, α1 represents an X-axis direction miscut angle, and α2 represents a Y-axis direction miscut angle.
Substituting the first galvanometer coordinate and the first image coordinate into a formula 5, and combining a least square method to obtain a value of the unknown number A, B, C, D, E, F; wherein the first galvanometer coordinate is substituted into (u, v) in equation 5, and the first image coordinate is substituted into (x, y) in equation 5;
obtaining a mapping relation between the first image coordinate and the first galvanometer coordinate according to a formula 5 and the value of the unknown number A, B, C, D, E, F;
wherein, the mapping relation is formula 6:
u＝Ax+By+C
v＝Dx+Ey+F。
further, verifying whether the local calibration mapping relationship satisfies the second preset precision in step S20 includes:
drawing a point Q in the field of view of the CCD camera through the marking software and engraving the point Q on the marking paper to be marked as a first verification point; wherein the sitting at point Q is marked (x 0, y 0).
Photographing by the CCD camera and identifying the image coordinates (x, y) of the first verification point.
And calculating according to the image coordinates (x, y) of the first verification point and a formula 6 to obtain verification galvanometer coordinates P (x 1, y 1).
And respectively comparing the coordinate (X0, Y0) of the point Q with the verification galvanometer coordinate P (X1, Y1) in the X-axis and Y-axis directions, and if the deviation of any direction is larger than a second preset deviation, the local calibration mapping relation does not meet the second preset precision. I.e. the size of the P, Q point is compared (the X-axis and the Y-axis of the two coordinate points are respectively different), if X, Y any direction deviation exceeds a second preset accuracy, the process continues to step S20, wherein the second preset accuracy is 0.01mm.
If the local calibration mode in the step S20 meets the second preset precision, the step S30 is executed, the laser galvanometer and the CCD camera are controlled to be calibrated globally, a global calibration model is obtained, and whether the global calibration model meets the third preset precision is verified.
Specifically, in step S30, global calibration is performed on the laser galvanometer and the CCD camera to obtain a global calibration model, which includes:
controlling marking software connected with the laser marking equipment to draw a second nine-point image file, and engraving the second nine-point image file on the calibration plate to form a second nine-point image; wherein the length and width of the second nine-point diagram file are 5mm-10mm larger than the length and width of the vibrating mirror breadth respectively; identifying second image coordinates of the second nine-point image through the deflection of the vibrating mirror; substituting the second image coordinates into the formula 6 respectively to obtain the coordinates of the deflection mirror; summing the coordinate of the deflection mirror with the coordinate R (s, t) of the mirror at the photographing position, and calculating the global coordinate of the mirror at nine points; obtaining a global calibration model according to the vibrating mirror global coordinate, the second image coordinate and the formula 5; substituting the global vibrating mirror coordinates of nine points and the picture file coordinates into a formula 5 to calculate the transformation relation of two coordinate systems, substituting the global vibrating mirror coordinates of nine points and the picture file coordinates into the formula 5 to calculate the transformation relation of two coordinate systems.
The global calibration model is formula 7:
o＝Hz+Iw+
p＝Kz+Lw+M
wherein (z, w) is (u, v) in the formula 6; (o, p) is the galvanometer global coordinates; H. i, J, K, L and M are unknowns.
Further, the relationship between the image coordinate system and the global coordinate system of the galvanometer can be obtained according to the formula 6 and the formula 7:
o=h ((ax+by+c) +s) +i ((dx+ey+f) +t) +j equation 8
P=k ((ax+by+c) +s) +l ((dx+ey+f) +t) +m formula 9
Wherein S, t is the shooting position galvanometer coordinate R (s, t).
Further, in step S30, the verifying whether the global calibration model meets the third preset precision includes: drawing a point R within the range of 5mm-10mm larger than the vibrating mirror breadth by using the marking software, and carving the point R on the calibration paper to serve as a second verification point; wherein the sitting at point R is marked (x 1, y 1); photographing and identifying image coordinates (x 2, y 2) of the second verification point by the CCD camera; calculating according to the image coordinates (x 2, y 2) of the second verification point and a formula 7 to obtain a verification global T (x 3, y 3); and respectively comparing the coordinates (X1, Y1) of the point R with the verification global coordinates T (X3, Y3) in the X-axis and Y-axis directions, and if any direction deviation is larger than a third preset deviation, failing to meet the third preset precision of the global calibration model, wherein the third preset precision is 0.01mm.
In the prior art, in order to prevent deviation, the vibration mirror often does not only take a picture and position at the center of the vibration mirror, but also positions a plurality of mark points by deflecting the vibration mirror to a plurality of areas, and then carries out a plurality of processing. Since the field lens focus lens has field curvature, the refractive index of the edge is not consistent with the refractive index of the center. In the laser control software, the box is calibrated to reduce the effect of field curvature. However, the illumination light source of the CCD is also affected by the field curvature, and the laser wavelength is very different from the wavelength of the CCD illumination light source, the parameters of the calibration box cannot be used in the calibration of the CCD, for the above problems, the prior art generally uses laser to engrave 9 (more than 3) small circles at each photographing point, visually identify the positions of the circles, and bind the camera image coordinates with the laser galvanometer coordinates through the visual calibration algorithm, but the inventor finds that the calibration error is large through the above method.
The calibration mode of the prior art is compared with the calibration mode of the application through the following experiment, and the calibration mode of the application can be compared with the calibration mode of the prior art through the comparison, so that the deviation is relatively smaller and more accurate.
Experimental parameters: aperture of galvanometerField lens focal length 160mm, field lens scanning breadth 200 x 200, field lens working distance: 192, ccd camera resolution: 2448 x 2048, ccd lens focal length: 75mm. The experimental mode is as follows: after calibrating CCD by using traditional vision calibration and the method described in the application, a circle with radius of 1mm is engraved on the calibration paper, and the circle is put onAnd (3) at different positions under the field lens (each position needs to be engraved with a circle again), coaxially visually identifying the position of the circle center, feeding back to the vibration lens, enabling the vibration lens to engrave a circle with the radius of 2mm by taking the circle center of visual feedback as the circle center, measuring concentricity of the two circles under a secondary element, respectively calculating difference values of the circle centers of the two circles in the x and y directions, and obtaining experimental result data as shown in table 1.
According to the method, the image distortion calibration is performed through the galvanometer scanning, after the distortion calibration meets the preset precision requirement, the camera coordinate system and the galvanometer coordinate system are used for local calibration, the relation between the two coordinate systems is locally calibrated according to the galvanometer after the distortion calibration is used, after the local calibration result meets the preset precision requirement, the camera coordinate system and the galvanometer coordinate system are used for global calibration, the local calibration result is used for completing all calibration, and the pixel coordinate conversion Cheng Zhenjing coordinates of the photographing result in the galvanometer scanning range are used for guiding the laser working position. The method overcomes the defect that in the existing laser coaxial vision, because the wavelength of the laser light source and the wavelength of the illumination light source have chromatic aberration, the positioning error exists when the positioning is performed by sharing one calibration during multi-position deflection photographing.
Fig. 4 shows a schematic structural diagram of the coaxial vision correction device according to the embodiment of the present application. The coaxial vision correction device is applied to a coaxial vision positioning system of a laser device, and the coaxial vision positioning system of the laser marking device comprises: the method comprises the following steps of:
the first calibration module 100 is configured to obtain a laser calibration file of the calibration system for image distortion, and verify whether the laser calibration file meets a first preset precision.
And the second calibration module 200 is configured to control to perform local calibration on the laser galvanometer and the CCD camera if the first preset precision is satisfied, obtain a local calibration mapping relationship, and verify whether the local calibration mapping relationship satisfies the second preset precision.
And the third calibration module 300 is configured to control global calibration of the laser galvanometer and the CCD camera if the local calibration meets the second preset precision, obtain a global calibration model, and verify whether the global calibration model meets the third preset precision.
It will be appreciated that the apparatus of this embodiment corresponds to the coaxial vision correction method of the above embodiment, and the options in the above embodiment are equally applicable to this embodiment, so the description will not be repeated here.
The present application also provides a terminal device, which exemplarily includes a processor and a memory, where the memory stores a computer program, and the processor executes the computer program, so that the terminal device performs the functions of the above-mentioned coaxial vision correction method or each module in the above-mentioned coaxial vision correction device.
The processor may be an integrated circuit chip with signal processing capabilities. The processor may be a general purpose processor including at least one of a central processing unit (Central Processing Unit, CPU), a graphics processor (Graphics Processing Unit, GPU) and a network processor (Network Processor, NP), a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware components. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like that may implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present application.
The Memory may be, but is not limited to, random access Memory (Random Access Memory, RAM), read Only Memory (ROM), programmable Read Only Memory (Programmable Read-Only Memory, PROM), erasable Read Only Memory (Erasable Programmable Read-Only Memory, EPROM), electrically erasable Read Only Memory (Electric Erasable Programmable Read-Only Memory, EEPROM), etc. The memory is used for storing a computer program, and the processor can correspondingly execute the computer program after receiving the execution instruction.
The present application also provides a readable storage medium for storing the computer program for use in the above terminal device.
In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other manners as well. The apparatus embodiments described above are merely illustrative, for example, of the flow diagrams and block diagrams in the figures, which illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
In addition, functional modules or units in the embodiments of the present application may be integrated together to form a single part, or each module may exist alone, or two or more modules may be integrated to form a single part.
The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application.
Claims (10)
1. A method of on-axis vision correction, the method being applied to an on-axis vision positioning system of a laser marking apparatus, the method comprising:
acquiring a laser calibration file of a calibration system for image distortion, and verifying whether the laser calibration file meets a first preset precision;
if the first preset precision is met, controlling to perform local calibration on the laser galvanometer and the CCD camera, obtaining a local calibration mapping relation, and verifying whether the local calibration mapping relation meets the second preset precision;
and if the local calibration meets the second preset precision, controlling to perform global calibration on the laser galvanometer and the CCD camera to obtain a global calibration model, and verifying whether the global calibration model meets the third preset precision.
2. The on-axis vision correction method of claim 1, wherein the calibration system is coupled to the laser marking device;
the laser calibration file for image distortion of the acquisition calibration system comprises:
setting correction chart file parameters through a calibration system, and controlling the laser marking equipment to carry out light-emitting carving on nine-point correction chart files according to the correction chart file parameters;
and measuring the coordinates of the remaining points of the nine-point correction chart file by taking the central point of the nine-point correction chart file as the central coordinate, inputting the coordinates of the nine points of the nine-point correction chart file into the calibration system and generating the laser calibration file.
3. The on-axis vision correction method as claimed in claim 1, wherein said verifying whether the laser calibration file satisfies a first preset precision comprises:
drawing a test shape through marking software and engraving the test shape on marking paper;
and measuring the actual size of the test shape drawn on the calibration paper, comparing the actual size with the drawing size of the marking software, and if the deviation of any one edge is larger than a first preset deviation, failing to meet the first preset precision of the laser calibration file.
4. A coaxial vision correction method according to claim 1 or 3, wherein the controlling locally calibrates the laser galvanometer and the CCD camera to obtain a local calibration mapping relation, and comprises:
controlling marking software connected with the laser marking equipment to draw a first nine-point image file, and recording first galvanometer coordinates of nine points in the first nine-point image file; the length and width of the first nine-point image file are smaller than the length and width of the field of view of the CCD camera, and the center of the first nine-point image file is the origin of the laser galvanometer coordinate system;
controlling the laser marking equipment to engrave the first nine-point image on the calibration paper to form a first nine-point image;
controlling the CCD camera to photograph the first nine-point image and identifying first image coordinates of nine points in the first nine-point image;
and obtaining a local calibration mapping relation through the first galvanometer coordinate and the first image coordinate.
5. The method of on-axis vision correction according to claim 4, wherein the obtaining the local calibration mapping relationship by the first galvanometer coordinate and the first image coordinate includes:
a translation transformation matrix is adopted for the first image coordinate to obtain a transformed coordinate;
wherein, the translation transformation matrix formula is:
obtaining transformed coordinates by adopting a scaling transformation matrix for the first image coordinates;
the scaling transformation matrix formula is as follows:
a rotation conversion matrix is adopted for the first image coordinate to obtain a converted coordinate;
the rotation conversion matrix formula is as follows:
obtaining transformed coordinates by adopting a miscut transformation matrix for the first image coordinates;
wherein, the formula of the miscut transformation matrix is:
the transformation matrix is combined according to the formula 1, the formula 2, the formula 3 and the formula 4:
in the formula, (X, Y) is a first image coordinate, (u, v) is a transformed coordinate, a represents a translation length along an X-axis direction, b represents a translation length along a Y-axis direction, s1 represents a scaling in the X-axis direction, s2 represents a scaling in the Y-axis direction, θ represents a rotation angle, α1 represents an X-axis direction miscut angle, and α2 represents a Y-axis direction miscut angle;
substituting the first galvanometer coordinate and the first image coordinate into a formula 5, and combining a least square method to obtain a value of an unknown number A, B, C, D, E, F; wherein the first galvanometer coordinate is substituted into (u, v) in equation 5, and the first image coordinate is substituted into (x, y) in equation 5;
obtaining a mapping relation between the first image coordinate and the first galvanometer coordinate according to a formula 5 and the value of the unknown number A, B, C, D, E, F;
wherein, the mapping relation is formula 6:
u＝Ax+By+C
v＝Dx+Ey+F。
6. the coaxial vision correction method of claim 5, wherein verifying whether the local calibration mapping satisfies a second preset precision comprises:
drawing a point Q in the field of view of the CCD camera through the marking software and engraving the point Q on the marking paper to be marked as a first verification point; wherein the sitting at point Q is marked (x 0, y 0);
photographing and identifying image coordinates (x, y) of the first verification point by the CCD camera;
calculating according to the image coordinates (x, y) of the first verification point and a formula 6 to obtain verification galvanometer coordinates P (x 1, y 1);
and respectively comparing the coordinate (X0, Y0) of the point Q with the verification galvanometer coordinate P (X1, Y1) in the X-axis and Y-axis directions, and if the deviation of any direction is larger than a second preset deviation, the local calibration mapping relation does not meet the second preset precision.
7. The coaxial vision correction method according to claim 5 or 6, wherein the controlling performs global calibration on the laser galvanometer and the CCD camera to obtain a global calibration model, comprising:
controlling marking software connected with the laser marking equipment to draw a second nine-point image file, and engraving the second nine-point image file on the marking paper to form a second nine-point image; wherein the length and width of the second nine-point diagram file are 5mm-10mm larger than the length and width of the vibrating mirror breadth respectively;
identifying second image coordinates of the second nine-point image through the deflection of the vibrating mirror;
substituting the second image coordinates into the formula 6 respectively to obtain the coordinates of the deflection mirror;
summing the coordinate of the deflection mirror with the coordinate R (s, t) of the mirror at the photographing position, and calculating the global coordinate of the mirror at nine points;
obtaining a global calibration model according to the vibrating mirror global coordinate, the second image coordinate and the formula 5;
the global calibration model is formula 7:
o＝Hz+Iw+J
p＝Kz+Lw+M
wherein (z, w) is (u, v) in the formula 6; (o, p) is the galvanometer global coordinate.
8. The on-axis vision correction method of claim 7, wherein the verifying whether the global calibration model meets a third preset precision comprises:
drawing a point R within the range of 5mm-10mm larger than the vibrating mirror breadth by using the marking software, and carving the point R on the calibration paper to serve as a second verification point; wherein the sitting at point R is marked (x 1, y 1);
photographing and identifying image coordinates (x 2, y 2) of the second verification point by the CCD camera;
calculating according to the image coordinates (x 2, y 2) of the second verification point and a formula 7 to obtain a verification global T (x 3, y 3);
and respectively comparing the coordinates (X1, Y1) of the point R with the verification global coordinates T (X3, Y3) in the X-axis and Y-axis directions, wherein if any direction deviation is larger than a third preset deviation, the global calibration model does not meet the third preset precision.
9. An on-axis vision correction device for use in an on-axis vision positioning system of a laser marking apparatus, the device comprising:
the first calibration module is used for acquiring a laser calibration file of the calibration system for image distortion and verifying whether the laser calibration file meets a first preset precision;
the second calibration module is used for controlling the local calibration of the laser galvanometer and the CCD camera if the first preset precision is met, obtaining a local calibration mapping relation and verifying whether the local calibration mapping relation meets the second preset precision;
and the third calibration module is used for controlling the laser galvanometer and the CCD camera to perform global calibration if the local calibration meets the second preset precision, obtaining a global calibration model and verifying whether the global calibration model meets the third preset precision.
10. A laser marking apparatus, characterized in that it comprises a processor and a memory, the memory storing a computer program, the processor being adapted to execute the computer program to implement the coaxial vision correction method of any one of claims 1-8.
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| CN117697197A (en) * | 2024-01-31 | 2024-03-15 | 深圳市九州智焊未来科技有限公司 | Laser welding penetration detection chromatic aberration compensation method, detection method and storage medium |
| CN117754168A (en) * | 2024-01-31 | 2024-03-26 | 深圳市九州智焊未来科技有限公司 | Laser welding penetration detection system, correction method, detection method and storage medium |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117697197A (en) * | 2024-01-31 | 2024-03-15 | 深圳市九州智焊未来科技有限公司 | Laser welding penetration detection chromatic aberration compensation method, detection method and storage medium |
| CN117754168A (en) * | 2024-01-31 | 2024-03-26 | 深圳市九州智焊未来科技有限公司 | Laser welding penetration detection system, correction method, detection method and storage medium |
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