Abstract

Speckle metrology includes techniques such as speckle photography, photography-based speckle interferometry, electronic speckle pattern interferometry (ESPI) and speckle shearography. The most important technique of speckle metrology for engineering measurements is the ESPI, also currently called digital speckle pattern interferometry (DSPI). The purpose of this chapter is to present recent developments and applications of ESPI for measurement of three-dimensional deformations and strain as well as for non-destructive testing and quality inspections. Considering that people engaged in these areas are mainly researchers, engineers, and graduate students in engineering departments who work in engineering measurement or in experimental and photo mechanics, this chapter intends to convey how relatively easily ESPI can be applied by the non-specialist in the field of optics or, alternatively, by researchers in engineering areas such as the authors. In writing this chapter, the authors will attempt to provide a unified, self-contained treatment of the theory, practice and application of ESPI and hope it can serve as a reference for researchers in these areas.