Structured Light Phase Measuring Profilometry Pattern Design for Binary Spatial Light Modulators
This work addresses a specific bottleneck in phase measuring profilometry for 3-D scanning applications, offering an incremental improvement in pattern design for binary spatial light modulators.
The paper tackles the challenge of converting continuous-tone (contone) patterns to binary patterns for high-speed structured light 3-D scanning, introducing an algorithm that reduces pattern noise by over 3 times compared to traditional halftoning methods.
Structured light illumination is an active 3-D scanning technique based on projecting/capturing a set of striped patterns and measuring the warping of the patterns as they reflect off a target object's surface. In the case of phase measuring profilometry (PMP), the projected patterns are composed of a rolling sinusoidal wave, but as a set of time-multiplexed patterns, PMP requires the target surface to remain motionless or for scanning to be performed at such high rates that any movement is small. But high speed scanning places a significant burden on the projector electronics to produce contone patterns inside of short exposure intervals. Binary patterns are, therefore, of great value, but converting contone patterns into binary comes with significant risk. As such, this paper introduces a contone-to-binary conversion algorithm for deriving binary patterns that best mimic their contone counterparts. Experimental results will show a greater than 3 times reduction in pattern noise over traditional halftoning procedures.