High-resolution, high-speed three-dimensional shape measurement using projector defocusing," Opt. Eng., 2011

[28] Y. Gong* and S. Zhang, "High-resolution, high-speed three-dimensional shape measurement using projector defocusing," Opt. Eng., 50(2), 023603, 2011; doi: 10.1117/1.3534798

We present a high-resolution, high-speed three-dimensional (3-D) shape measurement technique that can reach the speed limit of a digital fringe projection system without significantly increasing the system cost. Instead of generating sinusoidal fringe patterns by a computer directly, they are produced by defocusing binary ones. By this means,with a relatively inexpensive camera, the 3-D shape measurement system can double the previously maximum achievable speed and reach the refreshing rate of a digital-light-processing projector: 120

"Ultrafast 3-D shape measurement with an off-the-shelf DLP projector," Opt. Express, (2010)

[26] Y. Gong* and S. Zhang, "Ultrafast 3-D shape measurement with an off-the-shelf DLP projector," Opt. Express 18(19), 19743-19754, 2010 (Cover Feature); doi: 10.1364/OE.18.019743

This paper presents a technique that reaches 3-D shape measurement speed beyond the digital-light-processing (DLP) projector’s projection speed. In particular, a “solid-state” binary structured pattern is generated with each micro-mirror pixel always being at one status (ON or OFF). By this means, any time segment of projection can represent the whole signal, thus the exposure time can be shorter than the projection time. A sinusoidal fringe pattern is generated by properly defocusing a binary one, and the Fourier fringe analysis means is used for 3-D shape recovery. We have successfully reached 4,000 Hz rate (80 μs exposure time) 3-D shape measurement speed with an off-the-shelf DLP projector