Speaker
Description
Pseudo-noise–based pulse-compression thermography has become an increasingly attractive alternative to conventional pulsed and lock-in approaches, as coded excitations enable high deposited energy while retaining broadband frequency content. However, practical implementation requires careful consideration of the inherent DC component introduced by the unipolar nature of the applied heating.
While explicit DC-removal procedures are typically required, this study shows that Legendre sequences can be modified such that they provide intrinsic DC-offset auto-compensation during correlation-based reconstruction. The natural offset cancellation achieved during matched filtering removes the need for polynomial DC-fitting or measurements near thermal steady-state conditions, thereby simplifying the processing chain while maintaining the full benefits of pulse-compression.
These findings highlight a practically relevant advantage of pseudo-noise thermography: the ability to simultaneously access high SNR, long-duration coded heating, and robust DC-offset suppression of the thermal excitation without additional modelling steps.
