Quantitative Surface Crack Evaluation Based on Eddy Current Pulsed Thermography

Eddy current pulsed thermography (ECPT) is an emerging non-destructive testing technology and has an increasing span of application with capabilities of rapid contactless and large surface area detection. The close process loop of ECPT that contains pre-processing, post-processing, and objective quantitative assessment is rarely presented. This paper proposed a complete strategy aims to perform pre- and post- processing for surface crack detection based on ECPT platform. In addition, the quantitative evaluation is involved to objectively evaluate detectability. Specially, a new post-image segmentation algorithm is proposed which based on the idea of grouping histogram and iterative adaption approach that leads to better performance for quantitatively identifying and sizing the defect. Experimental tests on man-made metal and natural defects have been conducted to show the reliability of the proposed strategy. This paper can be further applied for other types of defects detection, quantitative evaluation, and aid in the development of machine vision industry for automated visual inspection.