Parameter estimation from pulsed thermography data using the virtual wave concept

Abstract The aim of this work is the estimation of the specimen thickness from pulsed thermography data using the virtual wave concept. A virtual wave signal is calculated by applying a local transformation to the measured temperature data. This virtual wave is a solution of the wave equation, whereby for the parameter estimation also ultrasonic evaluation methods can be used, e.g. pulse-echo method for time-of-flight measurements. The time-of-flight is directly related to the distance traveled by the wave and can be used to reconstruct the position of the interface. This method yields a very good estimation of the thickness of a steel step wedge, with the advantage that the same evaluation method can be used for reflection as well as transmission measurements.