A comparison of feature extraction techniques for delamination of CFRP using Eddy current pulse-compression thermography

CFRP (carbon fiber reinforced plastic) has replaced conventional metallic materials in many industrial applications because of its outstanding mechanical performance such as high strength to ratio and resistance of fatigue. During the service life of the aerospace composite component, delamination left without detection can cause a sudden breakdown of the structure. Eddy current pulse-compression thermography (ECPuCT) is an emerging technique that combines traditional ECPT and pulse compression techniques. In this work, feature extraction techniques of impulse response have been exploited in terms of principal component analysis (PCA), kernel principal component analysis (K-PCA) and independent component analysis (ICA). Each technique is evaluated using SNR as the index to compare their performance. The results indicate that Kernel-PCA performs better than PCA and ICA based features when dealing with delamination ranged from defect#1(0.46mm) to defect#9 (2.30mm).