Laser scanning thermal wave phase-locked imaging system and method

Abstract

The invention relates to a laser scanning thermal wave phase-locked imaging system and method; the system performs periodical thermal excitation on the surface of a test piece via a high-power laser beam; an infrared thermal imager continuously collects sequence thermal wave images for test piece surface; amplitude of the test piece and a phase thermal wave image thereof are acquired via phase-locked imaging technology, thereby judging the inner structure and flaws of a material.

Description

technical field [0001] The invention relates to a thermal wave lock-in imaging system and method, in particular to a laser scanning thermal excitation technology, which belongs to the technical field of infrared non-destructive testing. Background technique [0002] Thermal wave imaging technology is a non-destructive testing method developed in modern times. Its basic principle is to use a thermal excitation source to heat the surface of the test piece to generate a temperature difference. The temperature difference forms a heat wave that propagates into the test piece. When the heat wave When a defect or a change in thermal impedance is encountered inside the test piece, part of the heat energy will be reflected and returned to the surface of the test piece, resulting in a dynamic distribution of temperature on the surface of the test piece. The thermal imager is used to record the information of the temperature change of the specimen surface over time, and then the therma...

AI Technical Summary

Problems solved by technology

But the shortcomings are also very obvious, such as the serious divergence of light radiation, so that it is not suitable for long-distance action, and thus the electrothermal conversion efficiency on the surface of the test piece is not high, and the size of the thermal excitation area is not easy to control, which depends entirely on the position of the lamp. Adjustment, and the uniformity of light radiation is not good

In addition, the thermal response of the lamp tube is relatively slow, and the infrared radiation radiated by the high temperature of the lamp itself will interfere with the acquisition of thermal wave images when reflected by the surface of the test piece, etc.

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