Quantitative mapping of depth profile of fatigue cracks using eddy current pulsed thermography assisted by PCA and 2D wavelet transformation

•The crack depth profile was evaluated by means of the eddy current pulsed thermography (ECPT) and a hybrid processing strategy.•A novel probe was utilized in ECPT to enhance the detection sensitivity and to provide a wide open-view area for the camera.•The hybrid strategy combining PCA and 2D wavelet transformation can efficiently extract the features of crack depth profile.•The research feasibility is validated through numerical simulation, nondestructive experiment, and destructive experiment.