SURFACE-TOPOGRAPHY MEASUREMENT USING DIGITAL MOIRE CONTOURING - ERRORS AND LIMITATIONS

Moire contouring is a technique that enables the surface topography of an object to be measured in a single view and has a wide range of potential applications in manufacturing. However, to be useful, it is necessary to be able to calibrate the system and establish the traceability of the calibration. In this paper, the factors that determine the accuracy of the technique are identified, methods of calibration proposed and attainable accuracies estimated. These include the optical magnification, phase measurement and sensitivity, all of which contribute to measurement errors in the technique. The methods are illustrated with results from a digital moire system, and the improvements required to obtain maximum accuracy are outlined.