Phase Measurement Method of Out-of-plane Deformation of Object Based on Digital Image Correlation

Abstract

The present invention discloses a digital image correlation-based object out-of-plane deformation phase measurement method. The method comprises the steps of (1) acquiring an interference fringe image before object deformation as a first frame of interference fringe image, and acquiring an interference fringe image after object deformation as a second frame of interference fringe image; (2) carrying out the gray processing on the first frame of interference fringe image and the second frame of interference fringe image, extracting the fringe frequency of the first frame of interference fringe image, and adopting a sub-pixel related algorithm to calculate an in-plane displacement field between the first frame of interference fringe image and the second frame of interference fringe image; (3) calculating and obtaining the out-of-plane deformation phase information after the object deformation according to the in-plane displacement field and the fringe frequency of the first frame of interference fringe image which are obtained in the step (2), and the relationship among the in-plane displacement field, the fringe frequency of the first frame of interference fringe image and an out-of-plane deformation phase, which is established based on an optical flow basic type. The method is simple and convenient in process, and is suitable for the dynamic measurement.

Description

technical field [0001] The invention relates to a method for measuring the out-of-plane deformation phase of an object based on digital image correlation. Background technique [0002] The optical interferometry method uses the interference of light for measurement, and has a relatively high sensitivity. It occupies a very important position in deformation measurement, such as electronic speckle interference, holographic interference, and moiré interferometry. The interferometry method includes two parts: optical path setting and information extraction of deformed fringes. Since the sensitivity of displacement measurement is related to the irradiation angle of the illumination light in the measuring device, different measuring devices can measure displacement components in different directions. The Michelson optical path is only sensitive to out-of-plane displacement, and the symmetrical optical path is only sensitive to in-plane displacement. After the optical path is set...

AI Technical Summary

Problems solved by technology

No researchers have been found to use digital image correlation methods to separate in-plane displacements from two interference fringe images, nor to use digital correlation methods to separate out-of-plane displacements from two interference fringe images

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