CN114279325A - System and method for calibrating spatial position relationship of vision measurement module measurement coordinate system - Google Patents
System and method for calibrating spatial position relationship of vision measurement module measurement coordinate system Download PDFInfo
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Abstract
The invention relates to a system and a method for calibrating the spatial position relationship of a coordinate system measured by a vision measurement module, which can quickly realize the accurate calibration of the spatial position relationship of the image measurement coordinate system of two machine vision measurement modules in a pose measurement device, can realize the conversion from a two-dimensional plane coordinate to a three-dimensional space coordinate in a two-dimensional image measurement coordinate system, materialize an abstract light spot imaging center and realize the contact measurement of the three-dimensional coordinate of a space image point in a three-coordinate measurement machine. The invention is mainly used for calibrating the space position relation of the image measurement coordinate system of the vision measurement module in the space pose measurement device, and ensures the measurement precision of the space pose measurement device.
Description
Technical Field
The invention belongs to the technical field of vision measurement, and particularly relates to a system and a method for calibrating a spatial position relation of a measurement coordinate system of a vision measurement module.
Background
The vision measurement technology has been developed rapidly in recent years because of its advantages such as non-contact property, high dynamic property, and high accuracy. The image sensor is used as a key device of a visual measurement technical product, plays a key role in acquiring partial images to be measured, and for the visual device which utilizes the multi-image sensor to realize measurement, the position relation calibration among image coordinate systems is the basis for realizing the whole measurement.
The conventional binocular vision camera external parameter calibration method, namely a two-measurement coordinate system relation calibration method, is a camera external parameter calibration method based on a Zhang Yongyou chessboard grid method, and the method uses the premise that two cameras can simultaneously acquire the same chessboard grid image, however, in some space position measurement devices based on laser and machine vision, on one hand, a working coordinate system of an image sensor is established on a laser imaging receiving screen, and on the other hand, due to the fact that the laser imaging receiving screen shields the image sensor, a plurality of image sensors cannot simultaneously and directly acquire a calibration board image, so that the conventional image coordinate system relation calibration method is not suitable any more.
The invention can effectively solve the problem of calibrating the relationship between the image coordinate systems established on the two image receiving screens in the space position measuring device based on laser and machine vision.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a system and a method for calibrating the spatial position relationship of a coordinate system measured by a vision measurement module, which can quickly realize the accurate calibration of the spatial position relationship of the image measurement coordinate systems of two machine vision measurement modules in a spatial pose measurement device.
The technical problem to be solved by the invention is realized by the following technical scheme:
the utility model provides a vision measurement module measures coordinate system spatial position relation calibration system which characterized in that: the calibration system comprises a space pose measuring device, a point structure light generator, a V-shaped positioning groove and a three-coordinate measuring machine,
the point structured light generator is used for generating point structured light and providing a point light spot image acquired by the image sensor in the calibration process;
the V-shaped positioning groove is used for installing a point structure light generator in the calibration process;
the three-coordinate measuring machine comprises a contact measuring head, a marble measuring platform, a measuring head movement remote control handle, an industrial personal computer and a measuring system, and is used for realizing contact measurement of a space coordinate point in a calibration process;
the space position and pose measuring device comprises two sets of image acquisition units, a laser beam splitting and refracting light path unit, an industrial personal computer and measuring software, wherein each image acquisition unit comprises an image sensing module A, an image sensing module B, a laser receiving screen A, a laser receiving screen B, an image sensor A and an image sensor B, each laser beam splitting and refracting light path unit comprises a laser beam splitting module and a refracting light path module, and the image sensor A and the image sensor B are fixedly connected to the rear sides of the laser receiving screen A and the laser receiving screen B respectively and used for acquiring laser spot images on the laser receiving screen; the industrial personal computer and the measurement software are connected with the image sensor A and the image sensor B through the USB, so that the image signals of the image sensor are collected, and the central coordinates of the light spots are extracted through the measurement software.
And the laser receiving screen A and the laser receiving screen B are both made of transparent acrylic plates, and the outer sides of the laser receiving screen A and the laser receiving screen B are coated with nano diffuse reflection coatings.
A calibration method for measuring the spatial position relationship of a coordinate system by a vision measurement module is characterized by comprising the following steps: the calibration method comprises the following steps:
1) thin board chessboard grids are pasted and placed on the inner sides of a laser receiving screen A and a laser receiving screen B of the space pose measuring device, perspective distortion and radial distortion of an image sensor A and the image sensor B are respectively corrected by a known camera distortion correction method, and the optical axes of the corrected image sensor A and the corrected image sensor B are perpendicular to the plane of the laser receiving screen;
2) taking down the laser beam splitting module and the plane mirror of the laser beam splitting module;
3) placing the space pose measuring device on a marble measuring platform of the three-coordinate measuring machine, starting the three-coordinate measuring machine, opening an industrial personal computer and a measuring system, and establishing a space pose measuring device coordinate system O-XYZ;
4) placing the point-structured light generator on the V-shaped positioning groove, opening the point-structured light generator, enabling the V-shaped positioning groove to be close to the laser receiving screen A, and ensuring that light spot imaging of the point-structured light generator (3-5) on the laser receiving screen A is located in the field range of the image sensor A;
5) the axis of the V-shaped positioning groove is perpendicular to the laser receiving screen A, the end face of the point structure light generator is tightly attached to the laser receiving screen A, and the coordinate value of the central point of the image facula collected by the image sensor at the moment is read out through the industrial personal computer and the measurement software;
6) rotating the point-structured light generator in the V-shaped positioning groove, observing the central coordinate value of the image light spot in the industrial personal computer and the measurement software, continuously adjusting the lens end face of the point-structured light generator to enable the lens end face to be tightly attached to the laser receiving screen A, ensuring that the central coordinate value of the laser light spot in the industrial personal computer and the measurement software does not change in the rotating process of the point-structured light generator, indicating that the center of the laser light spot is overlapped with the axis of the shell of the point-structured light generator, recording the central coordinate value (x1, y1) pixel of the light spot at the moment, fixing the point-structured light generator and the V-shaped positioning groove through a compressing device, and keeping the position relation with the receiving screen unchanged;
7) moving a contact type measuring head of a three-coordinate measuring machine by moving a remote control handle of the measuring head, performing cylindrical measurement on the surface of a shell of a point-structured light generator in an O-XYZ coordinate system, measuring at least 5 points, fitting a cylindrical surface, and constructing a central axis 1 by the fitted cylindrical surface;
8) moving a contact type measuring head of a three-coordinate measuring machine by moving a remote control handle of the measuring head, carrying out plane measurement on the inner surface of a laser receiving screen A under an O-XYZ coordinate system, measuring at least 5 points, and fitting a plane 1;
9) intersection point coordinates (X1, Y1 and Z1) of the equation of the central axis 1 and the corresponding equation of the plane A1 of the laser receiving screen are spatial position coordinates of the spot center of the point laser, and are marked as a mark point 1;
10) moving the point-structured light generator for a certain distance along the horizontal direction to ensure that the laser facula is still positioned in the field of view of the image sensor A after moving;
11) repeating the processes of the steps 5-9, recording the coordinate value (X2, Y2) pixel of the spot center of the rotating point structure light generator when the spot coordinate does not change, and the intersection point coordinate (X2, Y2, Z2) of the fitting axis equation of the point structure light generator shell and the plane equation of the laser receiving screen A at the moment, namely the space position coordinate of the spot center of the point laser at the moment, and recording the space position coordinate as a mark point 2;
12) placing the point-structured light generator on the V-shaped positioning groove, opening the point-structured light generator, and enabling the V-shaped positioning groove to be close to the laser receiving screen B to ensure that the spot imaging of the point-structured light generator on the laser receiving screen B is positioned in the field range of the image sensor B;
13) repeating the processes of the steps 4-11, and respectively recording coordinate values (X3, Y3) pixel of the center of the light spot of the mark point 3 in the image sensor B measuring coordinate system and the corresponding spatial position coordinates (X3, Y3, Z3) of the center of the laser light spot of the point, and coordinate values (X4, Y4) pixel of the center of the light spot of the mark point 4 in the image sensor B measuring coordinate system and the corresponding spatial position coordinates (X4, Y4, Z4) of the center of the laser light spot of the point;
14) installing the laser beam splitting module and installing a plane mirror;
15) in an industrial personal computer and a measuring system, an established O-XYZ space pose measuring device coordinate system is used as a measuring coordinate system, a probe is contacted with and measures a corresponding plane by controlling the remote control movable handle, each plane measures at least five points, and an equation fitting the plane of a corresponding laser beam splitter and the plane of three plane reflectors in a folding light path is measured;
16) and processing the light spot image coordinates and the space coordinate data under the space pose measuring device coordinate system to obtain the space position relation between the two coordinate systems.
Moreover, in the step 16), the processing method of the optical spot image coordinate and the space coordinate data comprises the following steps:
the equation of the plane where the laser beam splitter is arranged and obtained by fitting the three-coordinate measuring machine is as follows:
wherein: (A, B, C) is a normal vector of plane 1;
(Xa，Ya，Za) Is a point on plane 1;
the plane equation of the plane mirror (1-4-1) is:
wherein: (D, E, F) is the normal vector of the plane;
(Xb，Yb，Zb) Is a point on the plane;
the equation of the plane where the plane mirror (1-4-2) is located is as follows:
wherein: (G, H, I) is the normal vector of the plane,
(Xc，Yc，Zc) Is a point on the plane;
the equation of the plane where the plane mirror (1_4-3) is located is as follows:
wherein: (J, K, L) is the normal vector of the plane;
(Xd，Yd，Zd) Is a point on the plane;
the equation of the plane where the plane mirror (1-4-3) is located is as follows:
wherein: (M, N, P) is the normal vector of the plane;
(Xe，Ye，Ze) Is a point on the plane;
processing the data by using a pose measuring device coordinate system as a measuring coordinate system in an industrial personal computer and measuring software, solving a corresponding spatial position relation of the two image measuring coordinate systems in a pose measuring device coordinate system O-XYZ after beam splitting and folding light path actions, and performing mirror image plane R and mirror image symmetry points of a laser receiving screen plane A, a marking point 1 and a marking point 2 relative to a laser beam splitter (1-3-1) plane in the industrial personal computer and the measuring software to obtain a marking point 1 'and a marking point 2', wherein the spatial coordinate values can be read by three-coordinate measuring software;
a mirror plane S and mirror symmetry points of a plane reflector (1-4-3), a plane of a plane reflector (1-4-2) and a plane reflector (1-4-1) after spatial coordinate points of a plane of a laser receiving screen B, a mark point 3 and a mark point 4 are respectively symmetrical with respect to the plane of the plane reflector (1-4-3), are made in three-coordinate measuring software, and a mark point 3 'and a mark point 4' are obtained, wherein spatial coordinate values can be read out by three-coordinate measuring software;
let the equation for plane R be:
wherein: (X)r，Yr，Zr) Is a point on plane R;
(RX，RY，RZ: ) Is the normal vector of the plane;
the equation for plane S is:
wherein: (X)s，Ys，Zs: ) Is a point on plane R;
(Sx，SY，SZ) Is the normal vector of the plane;
1) calculating a rotation angle:
2) rotating the image coordinate system by a known method through the obtained rotation angle, so that the two image coordinate systems after the action of the measuring light path are parallel to the Y axis of the pose measuring coordinate system 0-XYZ; the coordinate values of the mark points 1 ', 2', 3 'and 4' after rotation are (X1 ', Y1', Z1 '), (X2', Y2 ', Z2'), (X3 ', Y3', Z3 ') and (X4', Y4 ', Z4');
3) calculating two image sensor conversion coefficients:
4) setting the pixel values of the image sensor as X0 and Y0 pixels, and calculating the space positions of the original points of the two image coordinate systems in a pose measurement coordinate system after the light path is acted: taking an image coordinate system of the image sensor A on the laser receiving screen A as an example for explanation:
let the three-dimensional coordinate of the coordinate system origin in the pose measurement coordinate system be (X)0，Y0，Z0) After the action of the optical path, the original point is on the plane R, so that the plane equation is satisfied:
origin (X)0，Y0，Z0) The distance from the OXY plane is L ═ K1 · y1+ Z1 ″, i.e.
Z0＝K1·y1+Z1″
Origin (X)0，Y0，Z0) The distance from the OYZ plane is L' ═ K1 · x1+ Y1 ″, i.e.
Y0＝K1·x1+Y1″
Coordinate values of the origin of the image coordinate system 1 in the measurement coordinate system O-XYZ are obtained by the above formula 3 in a simultaneous manner; similarly, the coordinate value of the origin of the image coordinate system 2 in the measurement coordinate system O-XYZ can be obtained, and the relation between the two coordinate systems can be obtained by combining the equation of the laser receiving screen A, B.
The invention has the advantages and beneficial effects that:
1. the calibration system and method for the spatial position relationship of the vision measurement module measurement coordinate system solve the problem that the relationship of the multi-image sensing system measurement coordinate system cannot be calibrated by using the traditional method due to shielding of the receiving screen, and can realize contact type accurate calibration of the spatial position relationship of the vision measurement module image measurement coordinate system in the spatial pose measurement device.
2. The system and the method for calibrating the spatial position relationship of the coordinate system measured by the vision measuring module can quickly realize the accurate calibration of the spatial position relationship of the image measuring coordinate system of the two machine vision measuring modules in the pose measuring device, can realize the conversion from the two-dimensional plane coordinate to the three-dimensional space coordinate in the two-dimensional image measuring coordinate system, materialize an abstract light spot imaging center and realize the contact type measurement of the three-dimensional coordinate of a space image point in a three-coordinate measuring machine. The invention is mainly used for calibrating the space position relation of the image measurement coordinate system of the vision measurement module in the space pose measurement device, and ensures the measurement precision of the space pose measurement device.
Drawings
FIG. 1 is a schematic structural diagram of a spatial pose measuring device of the present invention;
FIG. 2 is a schematic diagram of the calibration process of the present invention;
FIG. 3 is a schematic diagram of the calibration details of the present invention.
Description of the reference numerals
1-1: an image sensing module A; 1-2: an image sensing module B; 1-3: a laser beam splitting module; 1-4: a folded light path module; 1-1-1: an image sensor A; 1-1-2: a laser receiving screen A; 1-2-1: an image sensor B; 1-2-2: a laser receiving screen B; 1-3-1: a laser beam splitter; 1-4-1: a plane mirror 1; 1-4-2: a plane mirror 2; 1-4-3: a plane mirror 3; 2-1: a spatial pose measuring device; 2-2: a three-coordinate measuring machine; 2-3: an industrial personal computer and measurement software; 2-4: an industrial personal computer and a measurement system; 2-2-1: a measuring head movement remote control handle; 2-2-2: a contact probe; 3-1: measuring an X axis of a coordinate system by a space pose; 3-2: measuring a Y axis of a coordinate system by the space pose; 3-3: measuring a Z axis of a coordinate system by a space pose; 3-4: a V-shaped positioning groove; 3-5: point structured light generator.
Detailed Description
The present invention is further illustrated by the following specific examples, which are intended to be illustrative, not limiting and are not intended to limit the scope of the invention.
A calibration system for measuring the spatial position relationship of a coordinate system by a vision measurement module is innovative in that: the calibration system comprises a space pose measuring device 2-1, a point structure light generator 3-5, a V-shaped positioning groove 3-4 and a three-coordinate measuring machine 2-2,
the point structured light generator 3-5 is used for generating point structured light and providing a point light spot image acquired by the image sensor in the calibration process;
the V-shaped positioning grooves 3-4 are used for installing the point structure light generators in the calibration process;
the three-coordinate measuring machine 2-2 comprises a contact type measuring head 2-2-2, a marble measuring platform, a measuring head movement remote control handle 2-2-1 and an industrial personal computer and measuring system 2-4, and is used for realizing contact type measurement of a space coordinate point in a calibration process;
the space pose measuring device 2-1 comprises two sets of image acquisition units, a laser beam splitting and refracting light path unit, an industrial personal computer and measuring software 2-3, wherein each image acquisition unit comprises an image sensing module A1-1, an image sensing module B1-2, a laser receiving screen A1-1-2, a laser receiving screen B1-2-2, an image sensor A1-1-1 and an image sensor B1-2-1, the laser beam splitting and refracting light path unit comprises a laser beam splitting module 1-3 and a refracting light path module 1-4, the image sensor A1-1-1 and the image sensor B1-2-1 are fixedly connected to the rear sides of the laser receiving screen A1-1-2 and the laser receiving screen B1-2-2 respectively, the laser receiving screen is used for collecting laser spot images on the laser receiving screen; the industrial personal computer and the measurement software 2-3 are connected with the image sensor A1-1-1 and the image sensor B1-2-1 through a USB (universal serial bus), so that the image signals of the image sensor are collected, and the central coordinates of the light spots are extracted through the measurement software.
The laser receiving screen A1-1-2 and the laser receiving screen B1-2-2 are both made of transparent acrylic plates, and the outer sides of the laser receiving screen A1-1-2 and the laser receiving screen B1-2-2 are coated with nano diffuse reflection coatings.
A calibration method for measuring the spatial position relationship of a coordinate system by a vision measurement module is characterized by comprising the following steps: the calibration method comprises the following steps:
1) thin board chessboard grids are pasted and placed on the inner sides of a laser receiving screen A and a laser receiving screen B of the space pose measuring device, perspective distortion and radial distortion of an image sensor A and the image sensor B are respectively corrected by a known camera distortion correction method, and the optical axes of the corrected image sensor A and the corrected image sensor B are perpendicular to the plane of the laser receiving screen;
2) taking down the laser beam splitting module and the plane mirror of the laser beam splitting module;
3) placing the space pose measuring device on a marble measuring platform of the three-coordinate measuring machine, starting the three-coordinate measuring machine, opening an industrial personal computer and a measuring system, and establishing a space pose measuring device coordinate system O-XYZ;
4) placing the point-structured light generator on the V-shaped positioning groove, opening the point-structured light generator, and enabling the V-shaped positioning groove to be close to the laser receiving screen A, so that light spot imaging of the point-structured light generator 3-5 on the laser receiving screen A is ensured to be within the field of view of the image sensor A;
5) the axis of the V-shaped positioning groove is perpendicular to the laser receiving screen A, the end face of the point structure light generator is tightly attached to the laser receiving screen A, and the coordinate value of the central point of the image facula collected by the image sensor at the moment is read out through the industrial personal computer and the measurement software;
6) rotating the point-structured light generator in the V-shaped positioning groove, observing the central coordinate value of the image light spot in the industrial personal computer and the measurement software, continuously adjusting the lens end face of the point-structured light generator to enable the lens end face to be tightly attached to the laser receiving screen A, ensuring that the central coordinate value of the laser light spot in the industrial personal computer and the measurement software does not change in the rotating process of the point-structured light generator, indicating that the center of the laser light spot is overlapped with the axis of the shell of the point-structured light generator, recording the central coordinate value (x1, y1) pixel of the light spot at the moment, fixing the point-structured light generator and the V-shaped positioning groove through a compressing device, and keeping the position relation with the receiving screen unchanged;
7) moving a contact type measuring head of a three-coordinate measuring machine by moving a remote control handle of the measuring head, performing cylindrical measurement on the surface of a shell of a point-structured light generator in an O-XYZ coordinate system, measuring at least 5 points, fitting a cylindrical surface, and constructing a central axis 1 by the fitted cylindrical surface;
8) moving a contact type measuring head of a three-coordinate measuring machine by moving a remote control handle of the measuring head, carrying out plane measurement on the inner surface of a laser receiving screen A under an O-XYZ coordinate system, measuring at least 5 points, and fitting a plane 1;
9) intersection point coordinates (X1, Y1 and Z1) of the equation of the central axis 1 and the corresponding equation of the plane A1 of the laser receiving screen are spatial position coordinates of the spot center of the point laser, and are marked as a mark point 1;
10) moving the point-structured light generator for a certain distance along the horizontal direction to ensure that the laser facula is still positioned in the field of view of the image sensor A after moving;
11) repeating the processes of the steps 5-9, recording the coordinate value (X2, Y2) pixel of the spot center of the rotating point structure light generator when the spot coordinate does not change, and the intersection point coordinate (X2, Y2, Z2) of the fitting axis equation of the point structure light generator shell and the plane equation of the laser receiving screen A at the moment, namely the space position coordinate of the spot center of the point laser at the moment, and recording the space position coordinate as a mark point 2;
12) placing the point-structured light generator on the V-shaped positioning groove, opening the point-structured light generator, and enabling the V-shaped positioning groove to be close to the laser receiving screen B to ensure that the spot imaging of the point-structured light generator on the laser receiving screen B is positioned in the field range of the image sensor B;
13) repeating the processes of the steps 4-11, and respectively recording coordinate values (X3, Y3) pixel of the center of the light spot of the mark point 3 in the image sensor B measuring coordinate system and the corresponding spatial position coordinates (X3, Y3, Z3) of the center of the laser light spot of the point, and coordinate values (X4, Y4) pixel of the center of the light spot of the mark point 4 in the image sensor B measuring coordinate system and the corresponding spatial position coordinates (X4, Y4, Z4) of the center of the laser light spot of the point;
14) installing the laser beam splitting module and installing a plane mirror;
15) in an industrial personal computer and a measuring system, an established O-XYZ space pose measuring device coordinate system is used as a measuring coordinate system, a probe is contacted with and measures a corresponding plane by controlling the remote control movable handle, each plane measures at least five points, and an equation fitting the plane of a corresponding laser beam splitter and the plane of three plane reflectors in a folding light path is measured;
16) and processing the light spot image coordinates and the space coordinate data under the space pose measuring device coordinate system to obtain the space position relation between the two coordinate systems.
Moreover, in the step 16), the processing method of the optical spot image coordinate and the space coordinate data comprises the following steps:
the equation of the plane where the laser beam splitter is arranged and obtained by fitting the three-coordinate measuring machine is as follows:
wherein: (A, B, C) is a normal vector of plane 1;
(Xa，Ya，Za) Is a point on plane 1;
the plane equation of the plane mirror (1-4-1) is:
wherein: (D, E, F) is the normal vector of the plane;
(Xb，Yb，Zb) Is a point on the plane;
the equation of the plane where the plane mirror (1-4-2) is located is as follows:
wherein: (G, H, I) is the normal vector of the plane,
(Xc，Yc，Zc) Is a point on the plane;
the equation of the plane where the plane mirror (1-4-3) is located is as follows:
wherein: (J, K, L) is the normal vector of the plane;
(Xd, Yd, Zd) is a point on the plane;
the equation of the plane where the plane mirror (1_4-3) is located is as follows:
wherein: (M, N, P) is the normal vector of the plane;
(Xe，Ye，Ze) Is a point on the plane;
processing the data by using a pose measuring device coordinate system as a measuring coordinate system in an industrial personal computer and measuring software, solving a corresponding spatial position relation of the two image measuring coordinate systems in a pose measuring device coordinate system O-XYZ after beam splitting and folding light path actions, and performing mirror image plane R and mirror image symmetry points of a laser receiving screen plane A, a marking point 1 and a marking point 2 relative to a laser beam splitter (1-3-1) plane in the industrial personal computer and the measuring software to obtain a marking point 1 'and a marking point 2', wherein the spatial coordinate values can be read by three-coordinate measuring software;
a mirror plane S and mirror symmetry points of a plane reflector (1-4-3), a plane of a plane reflector (1-4-2) and a plane reflector (1-4-1) after spatial coordinate points of a plane of a laser receiving screen B, a mark point 3 and a mark point 4 are respectively symmetrical with respect to the plane of the plane reflector (1-4-3), are made in three-coordinate measuring software, and a mark point 3 'and a mark point 4' are obtained, wherein spatial coordinate values can be read out by three-coordinate measuring software;
let the equation for plane R be:
wherein: (X)r，Yr，Zr) Is a point on plane R;
(RX，RY，RZ: ) Is the normal vector of the plane;
the equation for plane S is:
wherein: (X)s，Ys，Zs: ) Is a point on plane R;
(SX，SY，SZ) Is the normal vector of the plane;
1) calculating a rotation angle:
4) rotating the image coordinate system by a known method through the obtained rotation angle, so that the two image coordinate systems after the action of the measuring light path are parallel to the Y axis of the pose measuring coordinate system 0-XYZ; the coordinate values of the mark points 1 ', 2', 3 'and 4' after rotation are (X1 ', Y1', Z1 '), (X2', Y2 ', Z2'), (X3 ', Y3', Z3 ') and (X4', Y4 ', Z4');
5) calculating two image sensor conversion coefficients:
4) setting the pixel values of the image sensor as X0 and Y0 pixels, and calculating the space positions of the original points of the two image coordinate systems in a pose measurement coordinate system after the light path is acted: taking an image coordinate system of the image sensor A on the laser receiving screen A as an example for explanation:
let the three-dimensional coordinate of the coordinate system origin in the pose measurement coordinate system be (X)0，Y0，Z0) After the action of the optical path, the original point is on the plane R, so that the plane equation is satisfied:
origin (X)0，Y0，Z0) The distance from the OXY plane is L ═ K1 · y1+ Z1 ″, i.e.
Z0＝K1·y1+Z1″
Origin (X)0，Y0，Z0) The distance from the OYZ plane is L' ═ K1 · x1+ Y1 ″, i.e.
Y0＝K1·x1+Y1″
Coordinate values of the origin of the image coordinate system 1 in the measurement coordinate system O-XYZ are obtained by the above formula 3 in a simultaneous manner; similarly, the coordinate value of the origin of the image coordinate system 2 in the measurement coordinate system O-XYZ can be obtained, and the relation between the two coordinate systems can be obtained by combining the equation of the laser receiving screen A, B.
Although the embodiments of the present invention and the accompanying drawings are disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the disclosure of the embodiments and the accompanying drawings.
Claims (4)
1. The utility model provides a vision measurement module measures coordinate system spatial position relation calibration system which characterized in that: the calibration system comprises a space pose measuring device (2-1), a point structure light generator (3-5), a V-shaped positioning groove (3-4) and a three-coordinate measuring machine (2-2),
the point structured light generator (3-5) is used for generating point structured light and providing a point light spot image acquired by the image sensor in the calibration process;
the V-shaped positioning groove (3-4) is used for calibrating the installation point structure light generator in the process;
the three-coordinate measuring machine (2-2) comprises a contact type measuring head (2-2-2), a marble measuring platform, a measuring head movement remote control handle (2-2-1), an industrial personal computer and a measuring system (2-4), and is used for realizing contact type measurement of a space coordinate point in a calibration process;
the space pose measuring device (2-1) comprises two sets of image acquisition units, a laser beam splitting and refracting light path unit, an industrial personal computer and measuring software (2-3), wherein each image acquisition unit comprises an image sensing module A (1-1), an image sensing module B (1-2), a laser receiving screen A (1-1-2), a laser receiving screen B (1-2-2), an image sensor A (1-1-1) and an image sensor B (1-2-1), each laser beam splitting and refracting light path unit comprises a laser beam splitting module (1-3) and a refracting light path module (1-4), and the image sensor A (1-1-1) and the image sensor B (1-2-1) are fixedly connected to the laser receiving screen A (1-1-2) and the image sensor B (1-2-1) respectively, The rear side of the laser receiving screen B (1-2-2) is used for collecting laser spot images on the laser receiving screen; the industrial personal computer and the measurement software (2-3) are connected with the image sensor A (1-1-1) and the image sensor B (1-2-1) through a USB (universal serial bus), so that the image signals of the image sensor are collected, and the center coordinates of the light spots are extracted through the measurement software.
2. The vision measurement module measurement coordinate system spatial position relationship calibration system of claim 1, wherein: the laser receiving screen A (1-1-2) and the laser receiving screen B (1-2-2) are both made of transparent acrylic plates, and the outer sides of the laser receiving screen A (1-1-2) and the laser receiving screen B (1-2-2) are coated with nano diffuse reflection coatings.
3. The calibration method for the spatial position relationship of the vision measurement module measurement coordinate system according to claim 1 or 2, characterized in that: the calibration method comprises the following steps:
1) thin board chessboard grids are pasted and placed on the inner sides of a laser receiving screen A and a laser receiving screen B of the space pose measuring device, perspective distortion and radial distortion of an image sensor A and the image sensor B are respectively corrected by a known camera distortion correction method, and the optical axes of the corrected image sensor A and the corrected image sensor B are perpendicular to the plane of the laser receiving screen;
2) taking down the laser beam splitting module and the plane mirror of the laser beam splitting module;
3) placing the space pose measuring device on a marble measuring platform of the three-coordinate measuring machine, starting the three-coordinate measuring machine, opening an industrial personal computer and a measuring system, and establishing a space pose measuring device coordinate system O-XYZ;
4) placing the point-structured light generator on the V-shaped positioning groove, opening the point-structured light generator, enabling the V-shaped positioning groove to be close to the laser receiving screen A, and ensuring that light spot imaging of the point-structured light generator (3-5) on the laser receiving screen A is located in the field range of the image sensor A;
5) the axis of the V-shaped positioning groove is perpendicular to the laser receiving screen A, the end face of the point structure light generator is tightly attached to the laser receiving screen A, and the coordinate value of the central point of the image facula collected by the image sensor at the moment is read out through the industrial personal computer and the measurement software;
6) rotating the point-structured light generator in the V-shaped positioning groove, observing the central coordinate value of the image light spot in the industrial personal computer and the measurement software, continuously adjusting the lens end face of the point-structured light generator to enable the lens end face to be tightly attached to the laser receiving screen A, ensuring that the central coordinate value of the laser light spot in the industrial personal computer and the measurement software does not change in the rotating process of the point-structured light generator, indicating that the center of the laser light spot is overlapped with the axis of the shell of the point-structured light generator, recording the central coordinate value (x1, y1) pixel of the light spot at the moment, fixing the point-structured light generator and the V-shaped positioning groove through a compressing device, and keeping the position relation with the receiving screen unchanged;
7) moving a contact type measuring head of a three-coordinate measuring machine by moving a remote control handle of the measuring head, performing cylindrical measurement on the surface of a shell of a point-structured light generator in an O-XYZ coordinate system, measuring at least 5 points, fitting a cylindrical surface, and constructing a central axis 1 by the fitted cylindrical surface;
8) moving a contact type measuring head of a three-coordinate measuring machine by moving a remote control handle of the measuring head, carrying out plane measurement on the inner surface of a laser receiving screen A under an O-XYZ coordinate system, measuring at least 5 points, and fitting a plane 1;
9) intersection point coordinates (X1, Y1 and Z1) of the equation of the central axis 1 and the corresponding equation of the plane A1 of the laser receiving screen are spatial position coordinates of the spot center of the point laser, and are marked as a mark point 1;
10) moving the point-structured light generator for a certain distance along the horizontal direction to ensure that the laser facula is still positioned in the field of view of the image sensor A after moving;
11) repeating the processes of the steps 5-9, recording the coordinate value (X2, Y2) pixel of the spot center of the rotating point structure light generator when the spot coordinate does not change, and the intersection point coordinate (X2, Y2, Z2) of the fitting axis equation of the point structure light generator shell and the plane equation of the laser receiving screen A at the moment, namely the space position coordinate of the spot center of the point laser at the moment, and recording the space position coordinate as a mark point 2;
12) placing the point-structured light generator on the V-shaped positioning groove, opening the point-structured light generator, and enabling the V-shaped positioning groove to be close to the laser receiving screen B to ensure that the spot imaging of the point-structured light generator on the laser receiving screen B is positioned in the field range of the image sensor B;
13) repeating the processes of the steps 4-11, and respectively recording coordinate values (X3, Y3) pixel of the center of the light spot of the mark point 3 in the image sensor B measuring coordinate system and the corresponding spatial position coordinates (X3, Y3, Z3) of the center of the laser light spot of the point, and coordinate values (X4, Y4) pixel of the center of the light spot of the mark point 4 in the image sensor B measuring coordinate system and the corresponding spatial position coordinates (X4, Y4, Z4) of the center of the laser light spot of the point;
14) installing the laser beam splitting module and installing a plane mirror;
15) in an industrial personal computer and a measuring system, an established O-XYZ space pose measuring device coordinate system is used as a measuring coordinate system, a probe is contacted with and measures a corresponding plane by controlling the remote control movable handle, each plane measures at least five points, and an equation fitting the plane of a corresponding laser beam splitter and the plane of three plane reflectors in a folding light path is measured;
16) and processing the light spot image coordinates and the space coordinate data under the space pose measuring device coordinate system to obtain the space position relation between the two coordinate systems.
4. The method for calibrating spatial position relationship of vision measurement module measurement coordinate system according to claim 3, characterized in that: the processing method of the optical spot image coordinate and the space coordinate data in the step 16) comprises the following steps:
the equation of the plane where the laser beam splitter is arranged and obtained by fitting the three-coordinate measuring machine is as follows:
wherein: (A, B, C) is a normal vector of plane 1;
(Xa，Ya，Za) Is a point on plane 1;
the plane equation of the plane mirror (1-4-1) is:
wherein: (D, E, F) is the normal vector of the plane;
(Xb，Yb，Zb) Is a point on the plane;
the equation of the plane where the plane mirror (1-4-2) is located is as follows:
wherein: (G, H, I) is the normal vector of the plane,
(Xc，Yc，Zc) Is a point on the plane;
the equation of the plane where the plane mirror (1-4-3) is located is as follows:
wherein: (J, K, L) is the normal vector of the plane;
(Xd，Yd，Zd) Is a point on the plane;
the equation of the plane where the plane mirror (1-4-3) is located is as follows:
wherein: (M, N, P) is the normal vector of the plane;
(Xe，Ye，Ze) Is a point on the plane;
processing the data by using a pose measuring device coordinate system as a measuring coordinate system in an industrial personal computer and measuring software, solving a corresponding spatial position relation of the two image measuring coordinate systems in a pose measuring device coordinate system O-XYZ after beam splitting and folding light path actions, and performing mirror image plane R and mirror image symmetry points of a laser receiving screen plane A, a marking point 1 and a marking point 2 relative to a laser beam splitter (1-3-1) plane in the industrial personal computer and the measuring software to obtain a marking point 1 'and a marking point 2', wherein the spatial coordinate values can be read by three-coordinate measuring software;
a mirror plane S and mirror symmetry points of a plane reflector (1-4-3), a plane of a plane reflector (1-4-2) and a plane reflector (1-4-1) after spatial coordinate points of a plane of a laser receiving screen B, a mark point 3 and a mark point 4 are respectively symmetrical with respect to the plane of the plane reflector (1-4-3), are made in three-coordinate measuring software, and a mark point 3 'and a mark point 4' are obtained, wherein spatial coordinate values can be read out by three-coordinate measuring software;
let the equation for plane R be:
wherein: (X)r，Yr，Zr) Is a point on plane R;
(RX，RY，RZ) Is the normal vector of the plane;
the equation for plane S is:
wherein: (X)s，Ys，Zs) Is a point on plane R;
(SX，SY，SZ) Is the normal vector of the plane;
1) calculating a rotation angle:
2) rotating the image coordinate system by a known method through the obtained rotation angle, so that the two image coordinate systems after the action of the measuring light path are parallel to the Y axis of the pose measuring coordinate system 0-XYZ; the coordinate values of the mark points 1 ', 2', 3 'and 4' after rotation are respectively (X1 ', Y1', Z1 '), (X2', Y2 ', Z2'), (X3 ', Y3', Z3 ') and (X4', Y4 ', Z4');
3) calculating two image sensor conversion coefficients:
4) setting the pixel values of the image sensor as X0 and Y0 pixels, and calculating the space positions of the original points of the two image coordinate systems in a pose measurement coordinate system after the light path is acted: taking an image coordinate system of the image sensor A on the laser receiving screen A as an example for explanation:
let the three-dimensional coordinate of the coordinate system origin in the pose measurement coordinate system be (X)O，YO，ZO) After the action of the light path, because the origin is on the plane RThis satisfies the plane equation:
origin (X)O，YO，ZO) The distance from the OXY plane is L ═ K1 · y1+ Z1 ″, i.e.
ZO＝K1·y1+Z1″
Origin (X)O，YO，ZO) The distance from the OYZ plane is L' ═ K1 · x1+ Y1 ″, i.e.
YO＝K1·x1+Y1″
Coordinate values of the origin of the image coordinate system 1 in the measurement coordinate system O-XYZ are obtained by the above formula 3 in a simultaneous manner; similarly, the coordinate value of the origin of the image coordinate system 2 in the measurement coordinate system O-XYZ can be obtained, and the relation between the two coordinate systems can be obtained by combining the equation of the laser receiving screen A, B.
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