Laser Scanning Thermography for Coating Thickness Inspection

Abstract

The paper deals with a new approach to laser thermography for the inspection of coating thickness. The approach is based on scanning the specimen surface point by point, using a low-power laser, and recording the temperature responses with an IR camera. A recorded sequence is then transformed into a sequence similar to a flash pulse thermography sequence. Fast Fourier transform was used as a processing technique. The results are compared with a flash pulse thermography measurement. It was shown that the laser thermography measurement provides a higher sensitivity to thickness changes than flash pulse thermography measurement.