Solid-State Pulsed Time-of-Flight 3-D Range Imaging Using CMOS SPAD Focal Plane Array Receiver and Block-Based Illumination Techniques

Full realization of a solid-state 3-D range imager based on the pulsed time-of-flight method is presented. The system uses block-based segmented illumination in the transmitter realized with a 16-element common anode laser diode bar. The receiver is based on a single chip 2-D SPAD/TDC 0.35 μm CMOS array with 32 × 128 SPAD pixels and 257 TDCs. Segmentation of the illumination improves the SN_BGR in the detection and results in simpler receiver realization than in the commonly used flood-illumination approach. The system is capable of producing cm-accurate 3-D range images within a FOV of 40° × 10° up to a range of 15 m in normal office lighting at a frame rate of ∼30 fps using a low average illumination power of only 2.6 mW. In background illumination of ∼20 klux, 3-D range images were captured at a distance of ∼13 m using the gated SPAD approach at a frame rate of ∼1 fps.