Novel Pulse Detection System Using Differentiation: Optical Experimental Results

Light Detection And Ranging (LiDAR) sensors play an important role in obstacle detection and avoidance in autonomous vehicles. In a Direct Time of Flight (DTOF) LiDAR, pulse detection is an important function which is often accomplished using high speed ADCs with sampling rates in the range of 0.5-1 giga samples per second. This poses problems for multi-channel, single chip LiDAR sensors due to area and power requirements of giga sample ADCs. In this paper, experimental results are presented from an implementation of pulse detection using differentiation by employing comparators, a novel method. A prototype for pulse detection mechanism has been implemented on a PCB using an array of sample and hold capacitors followed by a comparator. The performance of a comparator-based pulse detection has been compared to that of an ADC-based pulse detection system. The control circuitry and data processing are implemented on a Xilinx ZYNQ-based FPGA. Results of distance measurement show that a comparator-based system can be used similar to an ADC-based system, but with significantly lesser resources in terms of area and power when implemented as an SoC.