Vol. 46, Issue 2, pp. 291-303
Keywords
phase measurement profilometry, digital-light-processing (DLP) projector, error diffusion algorithm, binary encoded grating
Abstract
Insufficient resolution of digital-light-processing projector will degrade the sinusoidal quality of the binary encoded fringe pattern because of less sampling points in a fringe period, which will degrade the measurement accuracy if it is used in phase measurement profilometry. Two resolutions are proposed in the paper. One is that a cylindrical lens is introduced in the projecting light path of the measurement system to improve sinusoidal quality of the binary encoded fringe by elliptical low-pass filtering of the system. The other one is that superposition of multi-frame binary encoded gratings with different microstructure is to reduce the binary image noise for improving the measurement accuracy. Simulations and experiments verify the validity of the above two methods.