Barker coded thermal wave imaging for anomaly detection

Barker code is a promising pulse compression friendly code useful for side lobe reduction and energy coagulation in main lobe to facilitate target identification in RADAR. It has been recently introduced in active thermal wave detection and ranging (TWDAR) for reliable subsurface analysis by replication of all its RADAR features for diffusive thermal waves and proved as one of the emerging anomaly detection modality with better resolution and detection capabilities. This paper presents an experimental study to assure these features using a Kevlor composite sample containing Teflon patches to simulate artificial delaminations, and CFRP specimen containing flat bottom holes using time domain pulse compression processing method and recently introduced orthonormal projection approach and compared its edge over the conventional FFT based phase analysis approaches.