Fast 3D reconstruction via event-based structured light with spatio-temporal coding.

Event-based structured light (SL) systems leverage bio-inspired event cameras, which are renowned for their low latency and high dynamics, to drive progress in high-speed structured light systems. However, existing event-based structured light methods concentrate on the independent construction of either time-domain or space-domain features for stereo matching, ignoring the spatio-temporal consistency towards depth. In this work, we build an event-based SL system that consists of a laser point projector and an event camera, and we devise a spatial-temporal coding strategy that realizes depth encoding in dual domains through a single shot. To exploit the spatio-temporal synergy, we further present STEM, a novel Spatio-Temporal Enhanced Matching approach for 3D reconstruction. STEM is comprised of two parts, the spatio-temporal enhancing (STE) algorithm and the spatio-temporal matching (STM) algorithm. Specifically, STE integrates the dual-domain information to increase the saliency of the temporal coding, providing a more robust basis for matching. STM is a stereo matching algorithm explicitly tailored to the unique characteristics of event data modality, which computes the disparity via a meticulously designed hybrid cost function. Experimental results demonstrate the superior performance of our proposed method, achieving a reconstruction rate of 16 fps and a low root mean square error of 0.56 mm at a distance of 0.72 m.