Multiprojector Multicamera Structured Light Surface Scanner

Abstract

Structured light surface scanners are usually limited to a single projector and cannot provide a full surface profile in a single scan. Multiple projectors must be employed to extend the imaging area over the whole surface of the imaged object. Using multiple projectors is a challenging problem due to inter-projector interference which make pattern decoding hard. We describe a practical approach to multi-projector structured light surface scanning based on sinusoidal fringe patterns and temporal phase shifting which allows simultaneous projector employment. In our approach a different set of temporal phase shifts is assigned to each projector to enable efficient and robust separation of observed combined patterns into the contributions of each projector. The proposed approach does not place any restrictions on projector placement nor on the upper limit of the number of projectors used. We demonstrate the applicability of the proposed approach on a structured light surface scanner comprised of three projectors and six cameras.INDEX TERMS structured light, 3D imaging, multi-projector structured light, temporal phase shifting, frequency-division multiplexing

Calibration of a Structured Light Imaging System in Two-Layer Flat Refractive Geometry for Underwater Imaging

“…For each camera and projector, two different positions of the calibration board constitute the minimum [ 24 ]. We proposed to use MPS-coded patterns, which enable simultaneous acquisition in a system comprising of an arbitrary number of projectors [ 31 , 32 ]. Another key point of the proposed approach is that, if there are multiple cameras observing the same part of the calibration board illuminated by a projector, then the number of extracted points for calibrating that particular projector is increased as measurements are repeated up to the number of cameras observing the illuminated board [ 21 ].…”