Spatial coherence profilometry on tilted surfaces.

The influence of tilted surfaces on the measurement of shape by spatial coherence profilometry is investigated. Based on theoretical analysis and experimental results, the systematic measurement error caused by surface tilt is determined. The systematic measurement error depends not only on the tilt angle but also on the parameters of the experimental setup. The theoretical analysis and the experiments show the similarities and differences between spatial coherence profilometry and white-light interferometry. We also suggest the conditions to obtain correct measurements by use of spatial coherence profilometry.