Larger surface profile measurement of microstructures by white-light phase-shifting interferometry and image stitching

摘要

White-light interferometry is very useful for highly resolved 3-D measurements of microscopic structures and micro devices. In this paper, a new stitching approach is developed to extend the measurement area. The characteristics of two neighboring images are enhanced by Laplacian filtering to reduce the effect of non-uniform illumination, and a proper sub-image is chosen based on the standard deviation of the sub-image for image correlation and stitching. Test of the method on the microstructure of a LCD panel shows that good stitching can be achieved within 1 pixel if the standard deviation of the comparing sub-image exceeds 7.1.