Sub-surface defect shape reconstruction method for thermal imaging detection

Abstract

The invention discloses a sub-surface defect shape reconstruction method for thermal imaging detection. The sub-surface defect shape reconstruction method consists of a thermal response signal acquisition process, a process of solving a phase difference between a defective region and a non-defective region, and a process of reconstructing a defect shape by adopting an envelope line. The method comprises the following steps: performing linear scanning on a test piece by adopting a linear thermal source; then performing Fourier analysis on data at a collected heating source position; solving corresponding phase differences between other position and non-defective positions; reversing the depths of defects according to the phase differences; then, making an envelope line according to scanning results of position lines, namely, solved depths; finally, estimating the shapes of the defects according to the envelope line. By adopting the sub-surface defect shape reconstruction method, the shapes of irregular defects can be estimated and reconstructed, quantitative assessment can be performed on the defects, and the problem on the aspect of quantitative analysis of the defects of the type during surface excitation is solved.

Description

technical field [0001] The invention belongs to the technical field of non-destructive testing of specimens containing subsurface defects, and more specifically relates to a shape reconstruction method for subsurface defects in thermal imaging testing. Background technique [0002] With the continuous development of science and technology, the quality and safety of mechanical equipment or components has become an issue of increasing concern. Infrared thermal imaging non-destructive testing technology plays an indispensable role in the safe operation of equipment, product quality control and ensuring that equipment is in a safe and reliable state. With its unique advantages, infrared thermal imaging non-destructive testing technology has become a new type of digital testing technology that is currently focused on development. Compared with traditional detection technology, it has the advantages of wide application range, non-contact, fast speed, on-site use, high precision, ...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art, and propose a method for reconstructing the shape of subsurface defects in thermal imaging detection, so as to facilitate the quantitative evaluation of subsurface defects and solve the problem of quantifying subsurface defects when surface excitation is used. analyse problem

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