Moiré profilometry using liquid crystals for projection and demodulation.

A projection moiré profilometer is presented in which both projection and optical demodulation are realized with liquid crystal light modulators. The computer generated grids, realized on thin film transistor matrices, allow phase-stepping and discrete grid averaging without the need for any mechanically moving component. Spatial line pitch and phase steps can thus be readily adjusted to suit the measurement precision and object geometry. The device is able to perform topographic measurements with a height resolution of 15 microm on every pixel of the recording device.