Optical deformation measurement method based on adaptive mesh and electronic equipment

Abstract

The invention relates to an optical deformation measurement method based on an adaptive mesh and electronic equipment. The measurement method comprises the following steps: acquiring a speckle image containing a region of interest, dividing uniform meshes in the region of interest, and determining an L-shaped curve in which the condition number of a corresponding coefficient matrix changes with the size of a mesh unit; taking the size corresponding to inflection points of the L-shaped curve as a unit size lower limit, taking the same size as an initial upper limit, and dividing uniform meshesin a second region range of the image, the second region including the region of interest; calculating and updating a displacement field according to the uniform meshes divided in the second region; and determining a strain gradient field of the region of interest according to the updated displacement field, determining unit size upper and lower limits according to the strain gradient field, and determining distribution of the unit size through a mapping relationship between strain gradients and unit sizes. According to the measurement method, the mesh size is selected in a self-adaptive mode,so that errors, caused by shape function mismatching, of the large-strain-gradient position and random errors of the small-strain-gradient position are reduced.

Description

technical field [0001] The invention relates to the field of optical measurement, in particular to an adaptive grid-based optical deformation measurement method and electronic equipment. Background technique [0002] Deformation measurement plays a vital role in the fields of engineering monitoring and scientific research. Among them, the optical deformation measurement method is widely used because it does not need to be in contact with the measured object and is flexible and simple to use. By dividing a series of units connected by nodes and comparing the gray information contained in the speckle image units before and after deformation, the displacement field distribution with sub-pixel accuracy can be obtained. Although in general, the existing technology methods can already obtain more accurate calculation results, but when calculating complex deformations, if larger-sized elements are used, the interpolation results will be caused because the shape function cannot accu...

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Problems solved by technology

[0003] In fact, only the positions with large deformation gradients need to be encrypted, and the positions with small deformation gradients will introduce new errors due to unit encryption: reducing the size of the unit will reduce the amount of information contained in the unit, which will increase the random error ; Improving the unit order will amplify the influence of noise, and both methods will increase the computational cost

However, most of the prior art methods use global encryption processing methods, and the selection of parameters such as cell size largely depends on the user's experience, which limits the further promotion of optical deformation measurement methods

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