Neural single-shot GHz FMCW correlation imaging

Abstract

Depth sensing is essential for 3D environmental perception across application domains, including autonomous driving, topographical mapping, and augmented and virtual reality (AR/VR). Traditional correlation time-of-flight (ToF) methods, while are able to produce dense high-resolution depth maps, are plagued by phase wrapping artifacts which limit their effective depth range. Though multi-frequency methods can help reduce this problem by simultaneously solving for phase wrap counts in multiple wavelengths, this requires multiple measurements per pixel, necessitating additional hardware and imaging time. We introduce a 3D imaging method that requires a single per-point measurement by combining frequency-modulated continuous wave (FMCW) operation, all-optical correlation ToF imaging, and a specialized frequency-decoding network. Our system performs all-optical correlation imaging at GHz rates. The method is validated through both simulations and real-world experiments, comparing favorably to existing methods in all experiments.