<title>Large depth-of-field moire system with remote image reconstruction</title>

Contouring objects which have a great deal of surface relief is often a challenge difficult to address with standard techniques because of the dynamic range involved. In particular, to produce a moire pattern over a large depth range requires a large depth-of-field and hence fairly course grating patterns. Removing the grating image from the resultant moire pattern is difficult since the grating is typically clearly resolved and comparable in period to the moire pattern. This paper describes a large depth-of-field moire projection system which uses remote reconstruction of the more fringes. The reconstruction system removes the grating lines via optical processing techniques, then analyzes the resulting clean moire using phase shift analysis within the optical processor. The output of the optical filtering is very high quality moire data over large depth ranges without any grating pattern present to disrupt the analysis. Potential application of this approach for use with photographic based field measurements is discussed.