Unified View Framework for Phase Correction in Multiprojector Structured Light Systems

Structured light illumination is a remarkable technique for active 3-D measurements. However, global or indirect light transport degrades the accuracy of phase calculation. This article describes an efficient phase correction and fusion framework for microscopic measurements. It targets a multiprojector system consisting of one camera coupled with multiple digital projectors. The phase-to-depth relationship is determined by using the native geometric model, taking lens distortion into consideration. By exploiting spatial consistency across multiple views, the phase from different projectors can be transformed into a unified view space. In this context, a reliability metric for unified phases is proposed to identify erroneous phase regions. Using preserved consistent views and the weighted histogram of the local neighborhood, phase error is first coarsely compensated by rectifying the doubtful period order. In addition, a novel hybrid weighting factor integrating signal and geometric reliability is proposed to further reduce measurement error. Experimental results from both qualitative and quantitative evaluation demonstrate the feasibility and usefulness of the proposed framework.