Effect of Spectral Reshaping on Frequency Modulated Thermal Wave Imaging for Non-destructive Testing and Evaluation of Steel Material

Infrared thermographic techniques show their potential usage for non-destructive testing and evaluation of various materials due to their inherent capabilities such as whole field, non-contact, qualitative and quantitative to detect surface and sub-surface anomalies. This contribution introduces a novel data analysis scheme by spectral reshaping of linear frequency modulated temperature profile captured over a mild steel specimen. Time and frequency domain based processing methods are adopted on the generated temporal thermal data to reveal the hidden defects. Obtained results show the potential capabilities of spectral reshaping based on Gaussian windowed chirp with enhanced resolution and sensitivity for sub-surface defect detection.