Combined digital image correlation displacement search method based on improved genetic algorithm

Abstract

The invention provides a combined digital image correlation displacement search method based on an improved genetic algorithm, and belongs to the field of non-contact optical measurement; the method comprises the following steps: obtaining digital image data before and after the deformation of a test piece for the test piece to be tested; performing displacement search by using an improved genetic algorithm; taking a displacement value obtained by searching of the genetic algorithm as an initial value of iteration of the NR algorithm, and solving a final displacement value; when genetic algorithm searching is carried out, setting the displacement value of a previous calculated node as a displacement vector reference of a next non-calculated node and the displacement value as a seed individual, and then acquiring an initialized population. The method has high displacement searching precision and speed, the initial value problem of the NR algorithm is solved, and the convergence speed of the genetic algorithm and the NR algorithm is increased.

Description

technical field [0001] The invention belongs to the field of non-contact optical measurement, and in particular relates to a combined digital image correlation displacement search method based on an improved genetic algorithm. Background technique [0002] The digital image correlation method is a non-contact optical measurement method, which is widely used in the mechanical performance test of materials because of its simple equipment, low environmental requirements, high measurement accuracy and non-contact. This method can easily obtain integer pixel displacement in practical applications, but the actual displacement value is generally not exactly an integer pixel, and the positioning accuracy of integer pixel displacement is far from enough in practical applications, so the sub-pixel displacement positioning algorithm is considered to be One of the key technologies in digital image correlation. [0003] The NR algorithm is one of the mainstream sub-pixel displacement al...

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Problems solved by technology

[0004] The present invention aims at the problem that the NR algorithm is sensitive to the initial value and the convergence problem of the genetic algorithm in the prior art, and proposes a combined digital image correlation displacement search method based on the improved genetic algorithm, which has high displacement search precision and speed, and solves the problem of The technical defects of the NR algorithm in the prior art are sensitive to the initial value, etc.

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