Feature Extraction Using Digital Image Correlation for Pulsed Eddy Current Thermographic Images
Abstract
Pulsed Eddy Current (PEC) thermography is a new method in the field of Non-Destructive Testing and Evaluation (NDT&E). The diffusion of heat in a specimen can be characterised by analysing a sequence of PEC thermography images, which correspond to defects. This study takes advantage from the capabilities of PEC thermography in gaining quantitative information for angular defect characterisation through the analysis of the surface thermal distribution. To carry out this analysis, a new technique using digital image correlation (DIC) has been proposed for tracking the heat diffusion through sequential PEC thermographic images in a metallic specimen. The results of the analysis have been used to extract the features of defects in the specimen under test. These results have shown the effectiveness of the proposed technique in providing features which have good agreement with defect detection and evaluation.
Keywords: Pulsed eddy current thermography, Digital image correlation, Feature Extraction, Quantitative evaluation.
1. Introduction
There is a growing need for effective, quick and reliable nondestructive evaluation (NDE) methods and techniques to inspect engineering component and complex structure to recognise possible sites of failure. Early detection and quantitative information for a defect proves an elementary factor when predicting the lifetime of a component [1].
The Pulsed eddy current (PEC) thermography technique has been used for defect detection and characterisation in conductive materials over a relatively wide area [2]. The technique uses induced eddy currents to heat the material being teste...
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Region of interest is an important feature provided by jpeg 2000 standard. The entire image is encoded as single entity by different fidelity constraints. This...
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