Active versus passive projector nonlinear gamma compensation method for high-quality fringe pattern generation

This paper presents our comparing study on active and passive methods for compensating the phase error induced by the projector nonlinear gamma effect. The active method modifies the fringe patterns before their projection; and the passive method, in contrast, compensates for the phase error after capturing fringe patterns. Our study finds that the active method tends to provides more consistent high-quality fringe patterns regardless the amount of projector's defocusing; yet the effectiveness of the passive method is sensitive to the measurement conditions, albeit the passive method could provide equally good quality phase under the optimal calibration condition. Experimental results will be presented to compare these two different methods.