A Structured Light 3-D Acquisition System with a CMOS Image Sensor for Background Suppression and Frequency and Phase Detection

Abstract

We propose and demonstrate a 3-D acquisition system with background suppression capability based on a structured light projection method. We have designed and demonstrated CMOS image sensor for frequency and phase detection by in-pixel digital demodulation circuit. The demodulation circuits suppress background light and extract modulated signal light that encodes angular information in frequency and phase from the background light. These in-pixel demodulation circuit has advantages in efficient and robust demodulation. The modulated signal light is projected using a high-speed DMD projector. We demonstrated -21 dB signal to background ratio without any optical filters, and 0.68 cm distance precision of the entire 3-D range finding system.