Overview of optical techniques that measure displacements: Murray lecture

Optical techniques that measure displacements play a very important role in current experimental mechanics, material sciences and metrology. This paper presents a survey of developments in these techniques from a personal experience point of view. Three main aspects are considered. Mathematical and numerical models used in the interpretation of fringe information and the corresponding data processing techniques. Optical and electro-optical developments that have taken place to improve the sensitivity, and the efficiency of these methods to make them competitive with purely numerical methods. Applications that have arisen from the synergy between advanced computational capabilities and optics are also presented.