Microscopic structured light 3D profilometry: Binary defocusing technique vs. sinusoidal fringe projection

•A comparison between binary and sinusoidal patterns under microscopic 3D profilometry.•Binary defocusing technique has 19% better depth resolution than sinusoidal method.•Binary defocusing could reach kHz 3D sensing under micro-scale.

This paper compares the binary defocusing technique with conventional sinusoidal fringe projection under two different 3D microscopic profilometry systems: (1) both camera and projector use telecentric lenses and (2) only camera uses a telecentric lens. Our simulation and experiments found that the binary defocusing technique is superior to the traditional sinusoidal fringe projection method by improving the measurement resolution approximately 19%. Finally, by taking the speed advantage of the binary defocusing technique, we presented a high-speed (500 Hz) and high-resolution (1600×1200) 3D microscopic profilometry system that could reach kHz.