A three-dimensional reconstruction algorithm for pulsed thermography

This paper presents a new algorithm for three-dimensional reconstruction of defect shape using pulsed thermography data. the aim is to detect and reconstruct the shape of defect located on the inaccessible rear face of a homogeneous material. the proposed method is based on the analysis of the object thermal response to a heat pulse. digital processing of the evolution of the temperature versus time allows the determination of a time value as a characteristic of the distance between the defect and the heated surface. the evaluation of the distance at each heated surface point allows the three-dimensional reconstruction of defect shape. the algorithm initial values are taken at the non defect area. the application of this algorithm to reconstruct the elliptic and triangular shape of a geometry defect located on the inaccessible face of steel and aluminum samples,confirmed the proposed algorithm.