Real-time, composite pattern, demodulation using optical correlators

Structured light illumination refers to a technique of acquiring 3-D surface scans through triangulation between a camera and a projector. Because traditional structured-light systems use multiple patterns projected sequentially in time, SLI is not typically associated with applications involving moving surfaces. To address this problem, the authors have introduced a technique referred to as composite pattern projection which involves the combining of a set of standard SLI patterns into a continuously projected pattern such that depth can be recovered from a single, captured image. As such, composite patterns can be used for tracking moving objects in 3-D space. The problem with composite patterns, though, is the added computational complexity associated with demodulating the captured image and extract the component SLI patterns. So in this paper, we introduce a means of achieving real-time pattern demodulation through the use of optical correlators with demonstrated results achieving a processing rate of over 100 frames per second.