3D Vision

3D sensing techniques for static or quasi-static events have been extensively studied over the past few decades. However, it remains challenging to capture rapidly occurring events. The state-of-the-art high-speed 3D sensing technique is either at low spatial resolution (typically cm to mm), at low temporal resolution (ranging from a few seconds to hours per 3D frame), or prohibitively expensive (typically over $500K). These limitations have severely hindered the use of 3D sensing techniques to facilitate numerous studies. Thus, this research pioneers the 3D sensing field by increasing its temporal resolution to a few magnitudes higher (e.g., kHz to MHz) while maintaining its highest possible spatial resolution (camera-pixel level). This innovative 3D sensing technology will introduce new paradigms to many fields, including experimental mechanics, medicine, computer science, and the manufacturing industry.

The novelty of this proposed research is: (1) the realization of superfast binary pattern switching by innovatively utilizing the nature of grayscale image generation in unmodified, inexpensive DLP projectors; (2) the generation of ideal sinusoidal fringe patterns by theoretically and experimentally understanding the binary defocusing phenomenon; (3) the marriage between binary structured light methods and sinusoidal fringe analysis techniques via the defocusing effect of the projector.

Figure 1 outlines the framework for superfast phase-shifting with unmodified inexpensive DLP projectors.


Fig. 1

Experimental mechanics will significantly benefit from the technology through the ability to capture dense and accurate 3D strain-stress fields at an unprecedentedly high speed. The novel technology will also greatly benefit medical practice by providing enhanced views of organs. Finally, measuring 3D dimensions of parts in production lines will lead to better quality assurance.