Parallel Acquisition of 3-D Surface Coordinates and Deformations by Combining Electronic Speckle Pattern Interferometry and Optical Topometry

Electronic Speckle Pattern Interferometry (ESPI) is a well-established tool for non-destructive testing which allows the detection of surface deformations and micro-movements on a sub-micrometer scale. The interpretation and evaluation of the resulting correlation fringe patterns, however, can be complicated by perspective image distortions as well as by an image scale varying with depth if the object under investigation is extended in depth. In this paper a method is presented which combines ESPI with a stereoscopic 3-D coordinate measurement using photogrammetry. With this approach every image detail including the fringe patterns can be precisely oriented in space.