Improvement of the contrast-to-noise ratio in pulse-phase thermography by frequency dependent windowing

Two modified algorithms for pulsed phase thermography were defined. The principle is to mask out parts of the thermal signal that only add noise but no significant information. The algorithms were tested on synthetic signals from a circular hidden defect and experimentally by flash excited thermography on a steel and a polymer sample. A significant improvement of the contrast-to-noise ratio of defects was obtained for higher analysis frequencies.