CN114111639B - Correction method and device of surface structured light three-dimensional measurement system - Google Patents
Correction method and device of surface structured light three-dimensional measurement system Download PDFInfo
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- 238000012937 correction Methods 0.000 title claims abstract description 99
- 238000005259 measurement Methods 0.000 title claims abstract description 86
- 238000000034 method Methods 0.000 title claims abstract description 43
- 239000011159 matrix material Substances 0.000 claims description 23
- 238000013519 translation Methods 0.000 claims description 12
- 238000010586 diagram Methods 0.000 description 3
- 238000003384 imaging method Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
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- 230000003287 optical effect Effects 0.000 description 2
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
- G01B11/254—Projection of a pattern, viewing through a pattern, e.g. moiré
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Abstract
The application provides a correction method and equipment of a surface structured light three-dimensional measurement system, which comprises the steps of correcting distortion in the system and acquiring a world coordinate system of a non-distortion measurement point; dividing an effective working range of a first direction in a world coordinate system into N sections; acquiring surface data of a standard correction block in each interval; determining a corresponding first coordinate value in each subarea, wherein the subareas are obtained by dividing each interval along a second direction and a third direction of a world coordinate system according to a preset size; performing surface fitting on the first coordinate values of all the subregions of each interval to determine a reference correction surface; determining a compensation amount of each sub-area, wherein the compensation amount is an average value of the deviation amounts of the corresponding surface data and the reference correction surface; and establishing a lookup table of sub-areas and compensation amounts in different areas under the world coordinate system of the undistorted measuring points. On the basis of distortion correction of the camera and the projector, system errors are eliminated, the measurement precision of the system is improved, and the measurement requirement of a high-precision measured object is met.
Description
Technical Field
The application relates to the technical field of surface structured light three-dimensional measurement, in particular to a correction method and correction equipment of a surface structured light three-dimensional measurement system.
Background
The surface structured light three-dimensional measurement system comprises a camera and a projector, wherein the camera and a lens of the projector are distorted, and the measurement accuracy of the system is affected; in practical application of the surface structured light three-dimensional measurement system, the measurement requirement of the high-precision measured object is higher and higher, so that the correction precision requirement of the surface structured light three-dimensional measurement system is higher and higher.
The correction of the surface structure three-dimensional measurement system mainly comprises the correction of distortion of a camera and a projector, the projector is regarded as a reverse camera, and the camera is a binocular system, and the internal parameters, the distortion coefficients and the external parameters of the camera and the projector are respectively calibrated through a calibration plate; and then, adopting a traditional camera distortion model to process different types of distortion such as radial distortion, tangential distortion and the like, and respectively realizing the distortion correction of the camera and the projector.
However, the three-dimensional measurement system of the surface structure mainly has measurement accuracy of tens of micrometers to hundreds of micrometers after the distortion correction, and is difficult to meet the measurement accuracy requirement of tens of micrometers of the measured object with high accuracy.
Disclosure of Invention
The application provides a correction method and equipment of a surface structure light three-dimensional measurement system, which are used for solving the technical problem that the measurement accuracy of the surface structure light three-dimensional measurement system is difficult to meet the measurement accuracy requirement of a measured object with high accuracy measurement requirement.
To achieve the above object, in a first aspect, an embodiment of the present application provides a correction method for a surface structured light three-dimensional measurement system, the correction method including the steps of:
Correcting the distortion in the system and obtaining the world coordinate system of the undistorted measuring points.
And dividing the effective working range of the first direction in the world coordinate system into N sections.
Surface data of a standard correction block, which is of known surface morphology, is acquired at each interval.
And determining a corresponding first coordinate value in each subarea, wherein the subareas are obtained by dividing the subareas along a second direction and a third direction of the world coordinate system according to a preset size in each interval, and the first coordinate values are average values of surface data corresponding to the subareas.
And carrying out surface fitting on the first coordinate values of all the subareas under each interval to determine a reference correction surface.
And determining a compensation amount of each sub-area, wherein the compensation amount is an average value of the deviation amount of corresponding surface data and the reference correction surface.
And establishing a lookup table under the world coordinate system of the undistorted measuring point, wherein the lookup table is the corresponding relation between the subareas and the compensation quantity under different intervals.
In one possible embodiment, the distortion in the correction system includes a distortion correction of the camera and a distortion correction of the projector.
In one possible embodiment, the distortion correction of the camera includes:
Calibrating camera parameters, wherein the calibrating camera parameters comprise the steps that firstly, a camera collects images of a calibrating plate at different positions; and calibrating camera parameters according to the calibration plate image, wherein the camera parameters comprise internal parameters, external parameters and distortion coefficients of the camera.
And carrying out distortion correction on the image acquired by the camera according to the camera distortion model and the camera parameters, and determining the image after distortion correction.
In one possible embodiment, the distortion correction of the projector includes the steps of:
Calibrating projector parameters, wherein the calibrating projector parameters comprise projecting patterns to a calibrating plate by a projector, and collecting the patterns projected to the calibrating plate by a camera; and calibrating projector parameters according to the pattern projected on the calibration plate and the pattern of the calibration plate, wherein the projector parameters comprise internal parameters, external parameters and distortion coefficients of the projector.
And determining a rotation matrix and a translation matrix from the camera coordinate system to the projector coordinate system according to the camera parameters and the projector parameters.
And determining projector pixel coordinates corresponding to a world coordinate system according to the camera distortion model, the projector parameters, the rotation matrix and the translation matrix.
And determining the undistorted projector pixel coordinates according to the projector pixel coordinates and the camera distortion model.
And determining a world coordinate system of the undistorted measuring point according to the rotation matrix, the translation matrix and the undistorted projector pixel coordinate.
In one possible implementation, after establishing the look-up table under the world coordinate system of the undistorted measurement point, the correction method further includes:
Obtaining corresponding compensation quantity in the lookup table according to the world coordinates of the measuring points on the object to be measured;
And correcting the world coordinates of the measuring points according to the corresponding compensation quantity.
In one possible embodiment, the surface data is obtained with the standard correction block disposed in the center of each section.
The method comprises the steps of correcting distortion in the system and acquiring a world coordinate system of a non-distortion measuring point; dividing an effective working range of a first direction in a world coordinate system into N sections; acquiring surface data of a standard correction block in each interval, wherein the standard correction block has a known surface morphology; determining a corresponding first coordinate value in each subarea, wherein the subareas are obtained by dividing the subareas in each interval along a second direction and a third direction of a world coordinate system according to a preset size, and the first coordinate values are average values of surface data corresponding to the subareas; performing surface fitting on the first coordinate values of all the subareas under each interval to determine a reference correction surface; determining a compensation amount of each sub-area, the compensation amount being an average of the deviation amounts of the corresponding surface data and the reference correction surface; and establishing a lookup table under a world coordinate system of the undistorted measuring points, wherein the lookup table is the corresponding relation between the subareas and the compensation quantity under different intervals. The application eliminates the system error on the basis of the distortion correction of the camera and the projector, improves the measurement precision of the system and meets the measurement requirement of a high-precision measured object.
In a second aspect, the present application further provides a calibration device for a surface structured light three-dimensional measurement system, and the calibration method for the surface structured light three-dimensional measurement system according to the first aspect is adopted.
The application provides a correction device of a surface structured light three-dimensional measurement system, which adopts a correction method of the surface structured light three-dimensional measurement system, eliminates systematic errors on the basis of distortion correction of a camera and a projector, improves the measurement precision of the system, and meets the measurement requirement of a high-precision measured object.
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In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is an imaging schematic diagram of a structured light three-dimensional measurement system according to an embodiment of the present application;
FIG. 2 is a flow chart of a calibration method for a three-dimensional measurement system of surface structured light according to an embodiment of the present application;
FIG. 3 is a flow chart of camera distortion correction in accordance with an embodiment of the present application;
FIG. 4 is a schematic diagram illustrating the interval division of the effective working range in the first direction according to the embodiment of the present application;
FIG. 5 is a schematic view of the distance between a measurement point and a fitted surface according to an embodiment of the present application;
FIG. 6 is a flow chart of a calibration method of a three-dimensional measurement system for structured light according to another embodiment of the present application;
wherein: 1-a video camera; 2-projector; 3-camera image plane; 4-projector image plane; 5-space plane; 6. 7-optical axis.
Detailed Description
In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. 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, shall fall within the scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the application described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The surface structured light three-dimensional measurement system includes a projector and an image pickup apparatus. Correcting the distortion of the structured light three-dimensional measurement system, namely, using a high-precision three-dimensional target for calibration by taking the image pickup equipment and the projector as a whole, wherein the precision of the three-dimensional target influences the measurement precision of the system by adopting the distortion correction method; the projector can also be used as a reverse camera, the surface structured light three-dimensional measurement system is a binocular system, parameters of the camera and the projector are respectively calibrated, and the distortion correction of the camera and the distortion correction of the projector are respectively realized.
The first mode needs a high-precision three-dimensional target and needs to model a system, and the modeling difficulty is high, and the high-precision three-dimensional target has high cost and high manufacturing difficulty. In the second mode, the calibration accuracy of the projector is insufficient, so that the overall measurement accuracy of the system is reduced, the offset measurement accuracy of the system is generally from hundreds of micrometers to tens of micrometers, and the accuracy of the system cannot meet the measurement requirement of a high-accuracy measured object.
In order to solve the problems, the embodiment of the application provides a correction method of a surface structured light three-dimensional measurement system, which improves the measurement precision of the system and meets the measurement requirement of a high-precision measured object by correcting the system distortion and eliminating the system error.
The image pickup device is used for collecting images, and the projection device is used for projecting specific structured light images in the surface structure three-dimensional measurement system. In some embodiments, the image capturing apparatus may be a video camera or a still camera.
As shown in fig. 1, an imaging schematic diagram of a surface structured light three-dimensional measurement system is shown, the surface structured light three-dimensional measurement system includes a projector 2 and a camera 1, in a space plane 5 where a world coordinate system Xw-Yw-Zw is located, a space point P coordinate (X W P,YW P,ZW P) of a surface of an object to be measured corresponds to a pixel point P c in an image plane 3 of the camera, a pixel point P p in an image plane 4 of the projector corresponds to the pixel point P p, the image plane 4 of the projector images in a direction of an optical axis 6 of the projector, and the image plane 3 of the camera images in a direction of an optical axis 7 of the camera.
As shown in fig. 2, the correction method of the surface structured light three-dimensional measurement system includes the following steps:
S101, correcting distortion in the system and acquiring a world coordinate system of a non-distortion measuring point.
The distortion in the correction system includes camera distortion correction and projector distortion correction, and the world coordinate system of the undistorted measurement points is a coordinate value corresponding to each measurement point readjusted under the world coordinate system.
Wherein the distortion correction of the camera comprises: firstly, calibrating camera parameters, then carrying out distortion correction on images acquired by a camera according to a camera distortion model and the camera parameters, and determining the images after distortion correction.
The camera parameter calibration method comprises the steps of selecting a proper calibration plate according to a Zhang Zhengyou calibration method, collecting a plurality of groups of calibration plate images at different positions, and calibrating the camera parameter according to the calibration plate images, wherein the camera parameter comprises an internal parameter, an external parameter and a distortion coefficient of the camera, and the internal parameter comprises an equivalent focal length, a principal point coordinate and lens distortion of a lens of the camera; the external parameters include a rotation matrix and translation vector of the camera coordinate system converted to the original coordinate system.
In some embodiments, the image of the calibration plate may be a checkerboard or a circular lattice.
According to the camera distortion model, radial distortion and tangential distortion can be corrected, in the distortion correction process, an undistorted image is obtained through known distortion images, and in particular, the mapping relation between the distortion image and the undistorted image can be obtained through the camera distortion model and camera parameters.
As shown in fig. 3, camera parameters are added into a camera distortion model to determine a distortion correction correspondence table; in the distortion correction correspondence table, the distortion amount (Δu, Δv) thereof is determined from the distorted image coordinates (u d,vd); and obtaining corresponding undistorted image coordinates according to the distortion quantity, obtaining gray values of the coordinates through a difference method, and determining the image after distortion correction.
Through the steps, the radial distortion and tangential distortion of the image acquired by the camera are eliminated, and the measurement precision of the surface structured light three-dimensional measurement system is improved.
Wherein, the projector distortion correction includes the following steps:
Calibrating projector parameters.
Because the projector cannot acquire images, calibrating projector parameters needs to be realized by a camera with calibration and distortion correction, and the method specifically comprises the following steps of: firstly, a projector projects a pattern to a calibration plate, and the pattern projected to the calibration plate is collected by the camera; and calibrating projector parameters according to the pattern projected on the calibration plate and the pattern of the calibration plate, wherein the projector parameters comprise internal parameters, external parameters and distortion coefficients of the projector.
And determining a rotation matrix R and a translation matrix T from the camera coordinate system to the projector coordinate system according to the camera parameters and the projector parameters.
The distortion correction for the projector is also correction for radial distortion and tangential distortion, and since the projector is an inverse camera, it is necessary to correct the projector after coordinate system conversion. The system projects through the projector, the camera collects specific structured light patterns, and the original world coordinates of the space points on the space plane are determined.
And determining projector pixel coordinates corresponding to a world coordinate system, namely, the pixel coordinates of a projector image plane, which are similar to the pixel coordinates of the camera image plane, according to the camera distortion model, the projector parameters, the rotation matrix and the translation matrix.
And then determining the undistorted projector pixel coordinates according to the projector pixel coordinates and the camera distortion model.
And finally, determining a world coordinate system of the undistorted measuring point according to the rotation matrix, the translation matrix and the undistorted projector pixel coordinate.
In some embodiments, cycling the correction step for the projector multiple times may achieve better correction, but that may consume more computing time, and may choose whether to cycle the correction step based on a particular measurement.
The influence of projector distortion on the structured light three-dimensional measurement system is reduced through the process, the accuracy of determining the world coordinate system of the undistorted measurement point is higher, and the measurement accuracy of the system is improved.
S102, dividing an effective working range of the first direction in the world coordinate system into N sections.
In the three-dimensional surface structured light measurement system, under the world coordinate system where no distortion measurement point is determined in correcting system distortion, the effective working range in the first direction (Z direction) is divided into N sections, as shown in fig. 4, and the effective working range in the Z direction is divided into N sections between z= -D and z=d, wherein the center z=0, and the size of the section is Δd for each section.
S103, acquiring surface data of the standard correction block in each interval.
The standard calibration block is of known surface morphology. The standard correction block can be a plane block, a step block, a spherical block and other correction blocks with known surface morphology.
The standard correction block has good surface flatness, manufacturing error smaller than 10 microns, low cost, easy realization and good imaging effect.
The surface data is obtained with the standard correction block disposed at the center of each section. As shown in fig. 4, the photographing surface of the standard correction block is adjusted to be within the corresponding photographing region, for example, for an interval of n=1, the surface of the standard correction block for photographing is placed within the interval, and a corresponding set of surface data is acquired; until the interval of n=n, the surface of the standard correction block for shooting is placed in the interval, and a corresponding set of surface data is acquired, wherein all the surface data are 3D curved surface data. And 3D curved surface data are acquired by taking the standard correction block as a shot object, so that the integrity of the acquired data is ensured.
S104, determining a corresponding first coordinate value in each sub-area.
The subareas are obtained by dividing the subareas along a second direction (X direction) and a third direction (Y direction) of a world coordinate system according to preset sizes in each interval, and the first coordinate values are average values of corresponding surface data in the subareas. Dividing the surface data obtained from each interval into subareas with the same size along the XY direction, wherein the subareas can be divided according to a preset size, and the unit of the preset size in the XY direction is pixel; and taking the Z value of the corresponding surface data in each sub-area as a mean value to obtain a first coordinate value.
S105, performing surface fitting on the first coordinate values of all the subareas under each interval, and determining a reference correction surface.
In some embodiments, for surface fitting, correction calculation may be performed by fitting 3D surface data captured in N intervals to N independent surfaces, or by fitting all data to N parallel surfaces.
S106, determining the compensation amount of each sub-area.
The compensation amount is an average value of the deviation amounts of the corresponding surface data and the reference correction surface. As shown in fig. 5, the distance, i.e., the amount of deviation, of each measurement point in the surface data in each sub-area from the reference correction surface (fitting surface) is calculated; and averaging all deviation amounts in the subareas to obtain the compensation amount of the subareas.
S107, establishing a lookup table of sub-areas and compensation amounts under different areas under the world coordinate system of the undistorted measuring points.
The lookup table is the corresponding relation between the subareas and the compensation quantity in different intervals.
For example, the effective working range of the surface structured light three-dimensional measurement system in the Z direction is-10 to +10mm, the effective working range can be divided into 20 sections at intervals of 1mm, 3D curved surface data are collected by taking standard correction blocks as shot objects in the shooting range of each section, subareas are divided along the XY direction by the size of 10 x 10pixel for each surface data of the 3D curved surface data, the average value of Z values in each subarea is used as a first coordinate value of the subarea, the reference correction face of the section is obtained by fitting curved surfaces through the first coordinate values of all subareas in one section, the average value of deviation amounts from each subarea to the fitted curved surfaces is calculated as compensation amounts of the areas under the height section, a lookup table is built according to the XY coordinate sections of the height section and the compensation amounts are stored in the lookup table for use in correction. In one specific implementation, the lookup table is a three-dimensional structure, wherein the table corresponding to the interval of 1mm-2mm in the Z direction is as follows:
List one
| Index X, Y | 0～9 | 10～19 | 20～29 | 30～39 | …… |
| 0～9 | 0.032 | 0.026 | 0.017 | 0.022 | …… |
| 10～19 | 0.021 | 0.017 | 0.045 | 0.026 | …… |
| 20～29 | 0.026 | 0.022 | 0.032 | 0.021 | …… |
| 30～39 | 0.045 | 0.032 | 0.021 | 0.017 | …… |
| …… | …… | …… | …… | …… | …… |
The unit of the index in the X and Y directions is pixel, and the unit of the compensation amount is millimeter mm.
After the lookup table is established, when the measurement points of the measured object are corrected, as shown in fig. 6, the correction method further includes the following steps:
s108, obtaining corresponding compensation quantity in the lookup table according to the world coordinates of the measuring points on the object to be measured.
And S109, correcting the world coordinates of the measuring points according to the corresponding compensation quantity.
And searching the height interval and the area of the measuring point according to the world coordinates of the measuring point, then searching the corresponding compensation quantity in the lookup table, and correcting the world coordinates of the measuring point by using the compensation quantity to obtain the world coordinates of the measuring point with residual errors eliminated.
In the embodiment, the camera and the projector in the system are respectively calibrated and corrected, and finally, the whole system is corrected by using the standard correction block. And the measurement error of a small system is improved, and the measurement accuracy is improved.
The application provides a correction method of a surface structured light three-dimensional measurement system, which comprises the steps of correcting distortion in the system and determining a world coordinate system of a non-distortion measurement point; dividing an effective working range of a first direction in a world coordinate system into N sections; acquiring surface data of a standard correction block in each interval, wherein the standard correction block has a known surface morphology; determining a corresponding first coordinate value in each subarea, wherein the subareas are obtained by dividing the subareas in each interval along a second direction and a third direction of a world coordinate system according to a preset size, and the first coordinate values are average values of surface data corresponding to the subareas; performing surface fitting on the first coordinate values of all the subareas under each interval to determine a reference correction surface; determining a compensation amount of each sub-area, the compensation amount being an average of the deviation amounts of the corresponding surface data and the reference correction surface; and establishing a lookup table under a world coordinate system of the undistorted measuring points, wherein the lookup table is the corresponding relation between the subareas and the compensation quantity under different intervals. The application eliminates the system error on the basis of the distortion correction of the camera and the projector, improves the measurement precision of the system, meets the measurement requirement of a high-precision measured object, and improves the measurement stability.
The application also provides a correction device of the surface structured light three-dimensional measurement system, and the correction method of the surface structured light three-dimensional measurement system is adopted. And on the basis of distortion correction of the camera and the projector, systematic errors are eliminated, the measurement precision of the system is improved, and the measurement requirement of a high-precision measured object is met.
The above is only for illustrating the technical idea of the present application, and the protection scope of the present application is not limited by this, and any modification made on the basis of the technical scheme according to the technical idea of the present application falls within the protection scope of the claims of the present application.
Furthermore, the order in which the elements and sequences are presented, the use of numerical letters, or other designations are used in the application is not intended to limit the sequence of the processes and methods unless specifically recited in the claims. While certain presently useful embodiments have been discussed in the foregoing disclosure by way of various examples, it is to be understood that such details are for the purpose of illustration only and that the appended claims are not limited to the disclosed embodiments, but rather are intended to cover all modifications and equivalent combinations that fall within the spirit and scope of the embodiments of the present application. For example, while the system components described above may be implemented by hardware devices, they may also be implemented solely by software solutions, such as installing the described system on an existing server or mobile device.
Similarly, it should be appreciated that in order to simplify the present disclosure and thereby facilitate an understanding of one or more embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure. This method of disclosure does not imply that the subject application requires more features than are set forth in the claims. Indeed, less than all of the features of a single embodiment disclosed above.
Each patent, patent application publication, and other material, such as articles, books, specifications, publications, documents, etc., cited herein is hereby incorporated by reference in its entirety. Except for the application history file that is inconsistent or conflicting with this disclosure, the file (currently or later attached to this disclosure) that limits the broadest scope of the claims of this disclosure is also excluded. It is noted that the description, definition, and/or use of the term in the appended claims controls the description, definition, and/or use of the term in this application if there is a discrepancy or conflict between the description, definition, and/or use of the term in the appended claims.
Claims (8)
1. A method of calibrating a structured-surface light three-dimensional measurement system, the method comprising:
Correcting distortion in the system and acquiring a world coordinate system of a distortion-free measuring point;
dividing an effective working range of a first direction in the world coordinate system into N sections;
acquiring surface data of a standard correction block in each interval, wherein the standard correction block has a known surface morphology;
determining a corresponding first coordinate value in each subarea, wherein the subareas are obtained by dividing the subareas in each interval along a second direction and a third direction of the world coordinate system according to a preset size, and the first coordinate values are average values of surface data corresponding to the subareas;
Performing surface fitting on the first coordinate values of all the subareas under each interval to determine a reference correction surface;
determining a compensation amount of each sub-area, the compensation amount being an average of the deviation amounts of the corresponding surface data and the reference correction surface;
Establishing a lookup table under the world coordinate system of the undistorted measuring points, wherein the lookup table is the corresponding relation between the subareas and the compensation quantity under different intervals;
after establishing the lookup table under the world coordinate system of the undistorted measurement point, the correction method further comprises the following steps:
Obtaining corresponding compensation quantity in the lookup table according to the world coordinates of the measuring points on the object to be measured;
Correcting world coordinates of the measuring points according to the corresponding compensation quantity;
the surface data is obtained with the standard correction block disposed at the center of each section.
2. A method of calibrating a structured light three-dimensional measurement system according to claim 1, wherein the distortions in the calibration system include a camera distortion calibration and a projector distortion calibration.
3. A method of calibrating a structured light three-dimensional measurement system according to claim 2, wherein the distortion correction of the camera comprises:
Calibrating camera parameters;
And carrying out distortion correction on the image acquired by the camera according to the camera distortion model and the camera parameters, and determining the image after distortion correction.
4. A method of calibrating a structured light three-dimensional measurement system according to claim 3, wherein calibrating camera parameters comprises:
the camera collects the calibration plate images at different positions;
And calibrating camera parameters according to the calibration plate image, wherein the camera parameters comprise internal parameters, external parameters and distortion coefficients of the camera.
5. A method of calibrating a structured light three-dimensional measurement system according to claim 3, wherein the distortion correction of the projector comprises:
Calibrating projector parameters;
Determining a rotation matrix and a translation matrix from a camera coordinate system to a projector coordinate system according to the camera parameters and the projector parameters;
and determining a world coordinate system of the undistorted measurement point according to the camera distortion model, the projector parameters, the rotation matrix and the translation matrix.
6. The method of calibrating a structured light three-dimensional measurement system according to claim 5, wherein calibrating projector parameters comprises:
The projector projects patterns to the calibration plate, and the patterns projected to the calibration plate are collected through the camera;
And calibrating projector parameters according to the pattern projected on the calibration plate and the pattern of the calibration plate, wherein the projector parameters comprise internal parameters, external parameters and distortion coefficients of the projector.
7. The method of calibrating a structured light three-dimensional measurement system according to claim 5, wherein determining a world coordinate system of undistorted measurement points based on a camera distortion model, the projector parameters, the rotation matrix, and the translation matrix comprises:
Determining projector pixel coordinates corresponding to a world coordinate system according to a camera distortion model, the projector parameters, the rotation matrix and the translation matrix;
determining undistorted projector pixel coordinates according to the projector pixel coordinates and a camera distortion model;
And determining a world coordinate system of the undistorted measuring point according to the rotation matrix, the translation matrix and the undistorted projector pixel coordinate.
8. A correction device for a surface structured light three-dimensional measurement system, characterized in that a correction method for a surface structured light three-dimensional measurement system as claimed in any one of claims 1 to 7 is used.
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