Laser shear speckle interferometry defect detecting system based on image registration and fusion

Abstract

The invention discloses a laser shear speckle interferometry defect detecting system based on image registration and fusion. The system comprises a laser light source, a beam expander, a beam splitter, a shearing device, a phase shifter, an image collector and a PC integrated with an image processing algorithm and a phase shifter control algorithm and is characterized in that double cameras and the image collector are utilized to simultaneously record the laser shear speckle interferometry stripe graphs of a to-be-detected object before and after heat loading and an original image, an image processing algorithm and a phase shifter control algorithm are used to process the laser shear speckle interferometry stripe graphs before and after the heat loading to obtain a phase difference image,and fusion and registration are performed on the phase difference image and the original image to fast and precisely positon defect detection positons.

Description

technical field [0001] The invention belongs to the technical field of defect detection, and more specifically relates to a laser shearing speckle interference defect detection system based on image registration and fusion. Background technique [0002] Laser shear speckle interferometry technology has full-field, non-contact, strong anti-interference ability to the environment, and high precision. It can directly measure the displacement derivative of the surface of the measured object due to defects such as internal debonding under thermal loading conditions. The environmental requirements are relatively low. These characteristics enable the laser shearing bulk interferometry technology to go out of the laboratory and be widely used in the debonding of aerospace composite materials and other tiny internal defects. Although this technology has been widely used in non-destructive testing in terms of principle or in practical experiments and applications, and has achieved man...

AI Technical Summary

Problems solved by technology

This device improves the detection accuracy, but the disadvantages are very obvious. First, the system is very complicated to establish and the cost is relatively expensive.

Secondly, the interference fringe pattern collected by the CCD contains very complex and diverse information, it is difficult to separate the signals, and it may also introduce additional noise information

[0011] Doctoral thesis "Research on vector light field control based on liquid crystal spatial light modulator" in 2014, "Synchronous phase-shifting common optical path interference based on liquid crystal spatial light modulator" in "Journal of Optoelectronics Laser" Volume 24 Issue 6 in 2013 Technology", "Digitalsckle shearing interferometer using a liquid-crystal spatial lightmodulator" in Volume 45, No. 10 of "Optical Engineering" in 2006. This device does reduce the time to obtain phase information, improve the energy utilization of light and reduce the interference of other light to the system, but the spatial light modulator is very expensive, and it does not involve in the accurate positioning of defect detection.

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