Phase unwrapping by a regularization technique in fracture measuring using ESPI

Detection and measurement of superficial fractures at engineering structures by means of ESPI techniques are very well known. However, several problems that still persist are the fracture detection on surfaces of irregular shape, or when the specimen is discontinuous. In this case the fringe analysis becomes very difficult and in occasions without solution, particularly in the process of phase unwrapping. In this work, experimental results are presented obtained by means of ESPI for the detection and measurement of fractures on a surface. Regularization techniques are used to obtain wrapped and to unwrap the phase of discontinuous specimens. Results are shown for several types of deformed objects with mechanical and thermal loads.