High dynamic range 3D measurement based on spectral modulation and hyperspectral imaging.

High-speed and high-accuracy three-dimensional (3D) measurement is of great importance in numerous areas. Recently proposed binary defocusing techniques have enabled breakthroughs in speed by utilizing 1-bit binary fringe patterns with the advanced digital light processing (DLP) projection platform. Meanwhile, much research has also been conducted to enhance measurement accuracy by temporally or spatially modulating the binary patterns. However, it is still challenging to use such techniques for measuring objects with high dynamic range (HDR) of surface reflectivity such as metal parts. To this end, we propose a novel HDR 3D measurement method based on spectral modulation and hyperspectral imaging. By modulating the illumination light with a spectral filter, and acquiring the fringe patterns with a hyperspectral camera, high-contrast HDR fringe imaging and 3D measurement can finally be achieved. Experiments were carried out to demonstrate the effectiveness of the proposed strategy.