A Method of Digital Speckle Full-field Deformation Measurement Based on Adaptive Window Matching

An adaptive window and digital speckle technology, applied in the field of computer vision, can solve the problems of fine deformation measurement of speckle image sequence and sudden change of stereo image parallax that cannot be directly applied

Active Publication Date: 2020-02-14
TONGJI UNIV
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Problems solved by technology

However, due to the problem of disparity mutations in stereoscopic images, the traditional fixed window matching strategy cannot solve such problems, so many scholars gradually use the variable window matching method to accurately extract the disparity boundary.
However, these methods cannot be directly applied to the measurement of subtle deformations in speckle image sequences.

Method used

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  • A Method of Digital Speckle Full-field Deformation Measurement Based on Adaptive Window Matching
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  • A Method of Digital Speckle Full-field Deformation Measurement Based on Adaptive Window Matching

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Embodiment

[0076] Simulation test: Gaussian speckle simulation experiment is used in this example

[0077] In order to verify the image matching strategy of this patent, robust speckle features and accurate deformation information can be provided through simulated images. Based on formula (4), the speckle simulation image can be generated by Gaussian random speckle. Among them, the initial speckle image is generated according to random speckle position and speckle radius, and the deformed speckle image is formed by setting different deformation parameters on the initial image.

[0078]

[0079] In formula (4), (u, v) is the image coordinate of each pixel, (u i ,v i ) is the image coordinate of the i-th speckle point, I i is the gray value of the i-th speckle point, R is the radius of the speckle point, (a 0 ,a 1 ,a 2 ,b0 ,b 1 ,b 2 ) is the affine deformation parameter. Such as Figure 6 Shown, according to the set parameters (M=16718, I i =rand(100~255), and =3 pixels) gene...

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Abstract

The invention relates to a digital speckle full-field deformation measurement method based on self-adaptive window matching, which comprises the following steps: 1) constructing a camera network: spraying digital speckles on the surface of an object to be measured, and arranging two cameras to shoot the object to be measured in a cross-direction photographing manner; 2) performing stereo matchingand target tracking; determining homonymous positions of target points in the left and right speckle image sequences by adopting a reliability guide matching mode, determining an optimal matching window for each target point by adopting a self-adaptive window matching method, finishing accurate target tracking by adopting least square matching, and obtaining two-dimensional sequence coordinates ofthe homonymous points in the speckle image sequences; and 3) performing full-field three-dimensional deformation measurement: according to the two-dimensional sequence coordinates of the homonymous points, adopting a collinear equation-based forward intersection algorithm to obtain the time sequence three-dimensional space coordinates of the target points, and completing the measurement of the deformation structure parameters of the to-be-measured object. Compared with the prior art, the method has the advantages of non-contact, rapidness and convenience.

Description

technical field [0001] The invention relates to the field of computer vision, in particular to a digital speckle full-field deformation measurement method based on adaptive window matching. Background technique [0002] In the construction of modern urbanization, the stability and safety of building materials have become the focus of attention. Therefore, before each special material is put into use, it is necessary to evaluate the structural performance and safety factor of the material through tensile / compression tests, crash tests, high-temperature tests and other testing experiments. However, traditional contact sensors are not suitable for full-field deformation measurement of materials due to defects such as single-point monitoring, limited measurement range, and difficult installation. With the rapid development of optical engineering, digital image correlation has become the main measurement method in mechanical analysis due to its non-contact advantages. This meth...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01B11/16
Inventor 童小华高飒陈鹏汪本康谢欢刘世杰金雁敏柳思聪许雄
Owner TONGJI UNIV
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