Optical sensors are very suitable for the analysis of microscopic structure
s and micro devices. We compare two very promising methods: the white-light
interferometry and the fringe projection technique for the application to
this task. The fringe projection is very useful for fast measurement of obj
ects with vertical dimensions of some mum. White-light interferometry is es
pecially useful for highly resolved 3-D measurements. Furthermore, we prese
nt a new technique. the scanning fringe projection (SFP), which enables abs
olute 3-D measurements with one single grating period. (C) 2001 Elsevier Sc
ience Ltd. All rights reserved.