Proceedings of SPIE - the International Society for Optical Engineering
Several methods for generation of three dimensional surface shapes from variable resolution video moire contours are described. In a classical moire system, a physical grating is projected on a target and also used to view the target. The moire contours are generated in the plane of the viewing grating. An unambiguous surface shape can then be computed by processing a set of moire images where the grating, target, or both are moved. By using an interferometer to generate and project variable pitch gratings and video technology to generate the moire contours, a 3-D surface can be scanned at different resolutions and used on a wide range of object sizes. The elimination of the physical grating also leads to surface generation techniques that do not use moving parts, increasing reliability. From these video moire contours, it is possible to uniquely reconstruct the 3-D surface, making the distinction between concave and convex surfaces. In one technique, a computer is used to mix digitized images of distorted gratings projected on the object with computer generated gratings, creating the moire patterns. By shifting one grating, it is possible to reconstruct the surface without having to move the object being scanned.
Blatt, Joel H.; Cahall, Scott C.; Gilbert, Bernard; Hooker, Jeffrey A.; and Wallace, Gary L., "Generation Of Surface Shape From Variable-Resolution Video Moire Contours" (1993). Aerospace, Physics, and Space Science Faculty Publications. 261.