SPAD Flash LiDAR with Chopped Analog Counter for 76m Range and 120klx Background Light

Abstract

Flash LiDAR sensors are becoming increasingly important in many automotive, space, and robotic applications. However, achieving long range, high depth resolution, and high frame rates simultaneously remains challenging, particularly under strong background light (BGL), as these requirements often conflict with each other [1], [2]. To address the requirements, direct time-of-flight (dToF) sensors using single-photon avalanche diodes (SPADs) and integrated histogramming have been actively investigated, achieving good spatial resolution and moderate frame rate, but only under limited BGL conditions (10″,,30klx in [2], [3]). In addition, the complexity of histogramming often results in large pixel pitch and small fill factor [4]. Recently, indirect ToF (iToF) sensors using SPADs, and counters have been demonstrated at longer ranges (50m [5] and 70m [6]). They are used to achieve small pixel pitch and high frame rate but suffer from significant performance degradations such as depth precision and range in strong BGL.