THEORY AND APPLICATIONS OF A SURFACE INSPECTION TECHNIQUE USING DOUBLE-PASS RETROREFLECTION

A historic perspective to the development of the D SIGHT(TM) surface inspection technique from a laboratory curiosity to a mature technology is presented. A brief description of the experimental process that led to the discovery of the phenomenon is followed by a discussion of how the optical process functions and how varying the hardware configuration affects the system output. Illustrations of a wide variety of surfaces, imaged using double-pass retroreflection, are used to show its evolution from a purely optical, visual enhancement technique to a computer-based, image acquisition system, which, through digital image processing, enables a user to quantify, annotate, and record the quality of a given surface. Possible directions for future development are discussed briefly.