3-d surface profilometry for accurate extraction of depth profile with lc phase modulator

We proposed a 3-D surface profilometry with a liquid crystal (LC) phase modulator for accurate extraction of the position and depth profile. The LC phase modulator was designed to develop the dynamic fringe patterns to be operated with multi-spatial frequencies, which were determined by changing the gap between micro-pinholes. The amount of phase shift was controlled by changing the applied voltage. In addition, the fictitious pattern scanning method and geometrical parameters were used to reconstruct position and depth profile of an object. As a result, the depth profile of object could be computed accurately with profilometry. Also, 3-D surface profilometry showed that integrated compact system could be constructed with the proposed scheme.