Comparative Study of Eddy Current Pulsed and Long Pulse Optical Thermography for Defect Detection in Aluminium Plate

Eddy current pulsed thermography (ECPT) and long pulse optical thermography (LPOT) as two emerging nondestructive testing and evaluation (NDT&E) techniques have been recently used for defect evaluation in many scenarios. This paper focuses on detecting the flat bottom hole (FBH) defects in an aluminium specimen by using both techniques. Principal component analysis (PCA) is used to enhance the FBH detection. The comparative results show that although LPOT has the advantage of a larger detection area and higher efficiency, the ECPT has a better performance compared to LPOT in detecting FBH defects in the aluminium specimen.