ABSTRACT
In this chapter, basics of the “fringe analysis,” which is one of the major methods for digitizing various physical phenomena, are briefl y introduced.
Merits of optical or image measurements are that they can quickly acquire spatial information of objects without contacting them. For example, in interferometry, which uses wave nature of light, a highly accurate distribution of physical information such as surface height, deformation, or indices of objects can be instantaneously obtained as a contour-like fringe pattern. Also, in the fringe projection techniques that typically apply the Moiré or the deformation grating principles, the height map of an object is visualized as a deformed fringe pattern and also a contour map. Although the fringe pattern obtained in these manners visualizes the physical conditions of the object, it is usually necessary to extract the quantitative values of the conditions from these patterns for metrological purposes. This process is called “fringe analysis,” which has rapidly developed together with image processing capabilities with computers and has become a large fi eld of modern image analysis.
