Highly precise AMCW time-of-flight scanning sensor based on parallel-phase demodulation

Abstract

A novel amplitude-modulated continuous wave (AMCW) time-of-flight (ToF) scanning sensor based on parallel-phase demodulation is proposed and demonstrated. Contrast to the conventional AMCW ToF sensor which utilizes serial-phase demodulation, the proposed sensor processes each different phase shift demodulation independently in parallel manner, so that the proposed sensor can maintain high demodulation contrast and short total integration time. Based on these characteristics of parallel-phase demodulation, the proposed sensor platform can be implemented with 2D laser scanning system with a single photodetector, maintaining a moderate frame rate, high optical SNR, and very high pixel resolution. In the validating demonstration, the proposed AMCW ToF scanning sensor shows extremely low measured distance noise per reference distance of 0.056 % at 1.50 m with only 30 mW illumination power. Additionally, FHD scale (1920 x 1080) highly precise 3D depth map with 800 nsec integration time can be achieved using the proposed AMCW ToF scanning sensor.