Stereoscopic visual structure three-dimensional distortion full-field measurement method

A technology of three-dimensional deformation and stereo vision, which is applied in the direction of measuring devices, instruments, and optical devices, etc., can solve the problems of large amount of calculation, long time consumption, and error of results, so as to improve accuracy and robustness, reduce the amount of calculation, shorten the time consuming effect

Inactive Publication Date: 2017-09-12
HARBIN INST OF TECH
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Problems solved by technology

[0005] The purpose of the present invention is to solve the problems that the existing N-R method has a large amount of calculation, takes a long time, has low precision, poor robustness, and the improper selection of the initial value of the least squares method will cause a large error in the result, and proposes a three-dimensional Full-field measurement method of 3D deformation of visual structure

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  • Stereoscopic visual structure three-dimensional distortion full-field measurement method

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specific Embodiment approach 1

[0029] Specific implementation mode 1: The specific process of a full-field measurement method for three-dimensional deformation of a stereoscopic vision structure in this implementation mode is as follows:

[0030] The invention provides a full-field measurement method and software for three-dimensional deformation of a stereoscopic structure, comprising: first selecting the left and right images at the initial time as the reference image at the initial time, and generating a measurement area in the reference image at the initial time by selecting points and setting the step length and forming The virtual grid performs three-dimensional matching on all grid nodes according to the digital image correlation method, and solves the initial three-dimensional coordinates of all grid nodes in the survey area. Then the left and right measurement areas are divided into 9 cells, and local search is performed according to the position of the cells where the grid nodes are located, and ti...

specific Embodiment approach 2

[0037] Specific embodiment two: the difference between this embodiment and specific embodiment one is: in the said step one, the images of civil engineering test specimens (such as reinforced concrete beams and reinforced concrete columns) are collected, and the images are calibrated by using the solid circle target three-step method , the stereo matching of the initial measurement area, and the initial three-dimensional coordinates of all grid nodes are obtained; the specific process is:

[0038] During the entire measurement process of the 3D deformation field, the 3D coordinates at the undeformed moment of the measurement area need to be used as the reference system, so the stereo matching of the left and right images at the initial moment is the first step in the entire measurement process. Considering the continuity of each point in the survey area at the initial moment, the present invention performs local search by limiting the stereo matching search area, and the specif...

specific Embodiment approach 3

[0047] Specific embodiment three: the difference between this embodiment and specific embodiment one or two is that in the step two, all the grid nodes obtained in step one are matched by blocks, and whether the matching is invalidated is judged by the correlation function threshold. If there is a mismatch in the matching, go to Step 3; if the blocks are matched correctly, get the coordinates of the grid nodes after matching; the specific process is:

[0048] After the stereo matching of the survey area at the initial moment, the three-dimensional coordinates of all grid nodes in the survey area are determined. In order to determine the matching points in the left and right image sequences at any moment during the deformation process, it is necessary to perform timing matching on all measurement points. The invention proposes a block matching algorithm. The idea of ​​this method is: divide the left and right measurement areas into 9 cells, and then perform local search accord...

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Abstract

The invention relates to a stereoscopic visual structure three-dimensional distortion full-field measurement method, aiming at solving the problems that the existing N-R method is large in calculating amount, more time-consuming, low in accuracy and poor in robustness, a larger error of the result is produced due to the improper selection of initial value calculated by using a least square method. The method comprises the following processes: 1, collecting an image of a civil experiment test piece so as to obtain initial three-dimensional coordinates of all grid nodes; 2, carrying out subdivision matching on all the grid nodes; if mismatching occurs during the subdivision matching, performing the step 3; if the subdivision matching is correct, obtaining coordinates of the matched grid nodes; 3, carrying out image matching on the mismatched nodes under the condition of large deformation so as to obtain coordinates of the matched grid nodes; 4, constructing a shape function so as to obtain a displacement field; 5, calculating the displacement field obtained in the step 4 by using a Green strain tensor so as to obtain a strain field, and outputting the displacement field and the strain field. The stereoscopic visual structure three-dimensional distortion full-field measurement method is used for the field of structure measurement.

Description

technical field [0001] The invention relates to a full-field measurement method for three-dimensional deformation of a stereoscopic vision structure. Background technique [0002] During the entire measurement process of the 3D deformation field, the 3D coordinates at the undeformed moment of the measurement area need to be used as the reference system, so the stereo matching of the left and right images at the initial moment is the first step in the entire measurement process. Since it is required to solve the three-dimensional coordinates of multiple points in the survey area, the global search method will increase the amount of calculation. Aiming at this problem, many scholars have proposed corresponding solutions. Helm et al. proposed a reverse projection method for searching and matching, but the model of this method is complex and cumbersome to implement. Chen Hua uses the combination of epipolar line constraints and sub-region gray level correlation to match, but n...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B11/16
CPCG01B11/16G01B11/002
Inventor 单宝华袁文厅王皓
Owner HARBIN INST OF TECH
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