Publications Details

Practical aspects of contouring using ESPI/DSPI

Reu, Phillip L.; Hansche, Bruce D.

Moiré contouring can be implemented by illuminating an object with coherent light from two closely spaced point sources-known as the "two point" method. This method can be implemented using digital speckle pattern interferometry techniques (DSPI) by illuminating the object with a single point source that is moved between datasets. We briefly present the algorithm, and some inherent implicit and explicit assumptions, used in this technique. One assumption made is that the object remains stationary between datasets. If violated, this bold assumption will create hundreds of microns of error from fractions of a micron of object motion. We present simulations and experiments demonstrating these sensitivities and two techniques to compensate for object motion during data acquisition. ©2008 Society for Experimental Mechanics Inc.