Simultaneous measurement of pure curvature and twist distribution fields by a five-aperture shearing and two-fourier filtering technique.

ABSTRACT

A five-aperture shearing and two-Fourier filtering technique to measure simultaneously pure curvature and twist distribution fields of a deformed object is proposed. In this method the slope fringes that are contained in the patterns of curvature and twist fringes can be completely eliminated. Thus patterns of pure curvature and twist fringes with a good contrast can be obtained. A theoretical analysis and experimental results are given.