Dual-projector structured light 3D shape measurement

Structured light illumination is an active three-dimensional scanning technique that uses a projector and camera pair to project and capture a series of stripe patterns; however, with a single camera and single projector, structured light scanning has issues associated with scan occlusions, multi-path, and weak signal reflections. To address these issues, this paper proposes dual-projector scanning using a range of projector/camera arrangements. Unlike previous attempts at dual-projector scanning, the proposed scanner drives both light engines simultaneously, using temporal-frequency multiplexing to computationally decouple the projected patterns. Besides presenting the details of how such a system is built, we also present experimental results demonstrating how multiple projectors can be used to (1) minimize occlusions; (2) achieve higher signal-to-noise ratios having twice a single projector's brightness; (3) reduce the number of component video frames required for a scan; and (4) detect multi-path interference.