Pulsed infrared thermography processing and defects edge detection using FCA and ACA

• CFRP sheet with delamination defects was detected using pulsed infrared thermography.
• A new polynomial fitting the derivative time-related coefficient algorithm (FCA) was proposed.
• Defects’ edge features have been extracted using ant colony algorithm (ACA) effectively.

CFRP sheet with delamination defects was detected using pulsed infrared thermography. The principle of polynomial fitting the derivative time algorithm (FDA) and related coefficient algorithm (RCA) was described. A new polynomial fitting the derivative time-related coefficient algorithm (FCA) was formed by combining FDA and RCA, which improves the signal to noise (SNR) of feature images, and is benefit for the detection and identification of defects. The defects edge identification procedure using ant colony algorithm (ACA) is given, and the defect edge features in the infrared image have been extracted using ACA effectively.