Experimental investigation of a time-power transformation method for flash-pulse thermographic testing

The paper deals with flash-pulse thermography, which is one of the most used thermographic inspection methods. The method is based on flash excitation of an inspected object and an analysis of its thermal response recorded by an infrared camera. This paper deals with a time-power transformation method (P-function) for an evaluation of the flash-pulse thermography measurement. The method is based on a transformation of the measured thermal response using a power function of time. An adaptation of the method is introduced, and an experimental investigation of the method is presented. The method and the evaluation procedure are described. A flash-pulse inspection of an experimental sample is performed, and the results of the inspection obtained by the P-function method and by a fast Fourier transform evaluation are compared using a contrast-to-noise ratio ranking. Advantages of the P-function method resulting from its numerical outputs for an estimation of the depth of defects are described. An influence of noise reduction and data preprocessing is discussed.