Range measurement using Talbot diffraction imaging of gratings

Abstract

A range measurement technique is presented which allows real-time range data acquisition for all points in an image. The technique relies upon the systematic variation in the Fresnel diffraction pattern of a grating as a function of propagation distance. The technique uses a single view of the volume in question so there are no hidden points. Furthermore, there is no need for beam scanning or is any off-line processing required. An extensive theory of operation is presented along with grating and illumination design methods which allow one to tailor the technique to specific measurement requirements. Qualitative experimental results are given along with quantitative results.