Dynamic detection system and method for digital shearing speckles by using 90-degree optical wave mixer

Abstract

The invention relates to a dynamic detection device for a material defect by using a 90-degree optical wave mixer. The dynamic detection device comprises a laser light source, a plurality of optical fibers, the 90-degree optical wave mixer, michelson interferometer-based shearing equipment and four sets of optical fiber interfaces CCD (Charge Coupled Device) with the same specification, wherein the laser light source is approximately vertically incident to a detected object; a shearing speckle interference signal is obtained by speckle signal light with defect information of the detected object through a set of shearing michelson interferometer; after being coupled to the optical fibers, the signal is input to the 90-degree optical wave mixer; optical signals of four channels output by theoptical wave mixer are received by the four sets of CCDs with the same specification, and thus four speckle interference images with a 90-degree phase difference are simultaneously received; that is,collection of four speckle interference patterns with the 90-degree phase difference in a common four-step time phase-shifting method can be realized by only needing to collect the time of a single image, thus the dynamic detection for the material defect is realized in high quality.

Description

Technical field [0001] The invention relates to a system for real-time, high-sensitivity and dynamic detection of defects in composite materials using digital shear speckle technology and a method based on the system. Background technique [0002] With the rapid development of modern industrial production, the state has paid more and more attention to the material industry, especially advanced composite materials used in the aviation industry and automobile manufacturing. As the basis of product manufacturing, the testing of product manufacturing materials is the key to controlling product quality. However, traditional detection methods face problems such as low detection efficiency. Compared with methods such as ultrasonic C-scan and eddy current detection, digital shear speckle technology can achieve convenient, fast, and full-field nondestructive detection. The shear speckle interferogram records the light intensity distribution map formed by the superposition and interferenc...

AI Technical Summary

Problems solved by technology

At present, the most commonly used phase shift method is to use PZT piezoelectric ceramics to move mirrors, tilt glass plates, and move diffraction gratings, etc., but there will be phase shift control errors in moving displacements.

In addition, because four speckle signals with a phase difference of 90° are acquired in time series, the consistency of speckle cannot be guaranteed, and it is not suitable for dynamic loading environment

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