Abstract
Vision systems capable of acquiring both two-dimensional and three-dimensional information through Light Detection And Ranging are assuming ever-increasing importance, being this market driven by the push from automotive companies to develop systems to be integrated in self-driving vehicles. Among others, candidate sensors for these systems are avalanche photodiodes, single-photon avalanche diodes, and silicon photomultipliers. Avalanche Photodiodes provide a good robustness to high background light at the cost of requiring an analog readout, instead Single-Photon Avalanche Diodes offer the possibility to implement digital readout and single-photon sensitivity, but are prone to saturation at extremely high background levels. We compare these three single- and multi-photon detector topologies, operated either in linear or digital regime, aiming at identifying the best suited detector to achieve the highest performance in Light Detection And Ranging applications at the lowest optical power active illumination and in presence of intense background (e.g. 100 klux). We present Matlab modelling and simulations and their experimental validation. Eventually, we propose a nomogram (referred to 100 m target distance) for identifying the most suited sensor topology across different operating areas and constraints, in order to achieve at least 70% success ratio.
Highlights
D URING the last decade, many automotive companies, such as Waymo, Ford, Toyota, Tesla and others, have been investigating reliable autonomous driving vision systems
As background light we employed either natural solar illumination or an LED and halogen lamp, whose power was adjusted in order to match solar illumination. Concerning detector readouts, both avalanche photodiode (APD) and analog silicon photomultiplier (SiPM) were coupled to a 450 MHz bandwidth Transimpedance Amplifier (TIA) and the output voltage waveforms were acquired by means of a 1 GHz bandwidth oscilloscope
Higher number of microcells allows to operate the analog SiPM with stronger background, theoretically reaching APD performance, while losing the capability of detecting one single-photon because of limited dynamic range, e.g. with 1024 cells and an output dynamic range of 3 V each single photon event will be less than 3 mV high, so a single photon event can be covered by the electronic noise
Summary
D URING the last decade, many automotive companies, such as Waymo, Ford, Toyota, Tesla and others, have been investigating reliable autonomous driving vision systems. The automotive market requires extreme reliability and negligible failure-rate in all possible atmospheric conditions, with the lowest possible active illumination for achieving eyesafe, long-range (hundreds of meters) measurements From this standpoint, SPADs are valid candidates since they can detect single photon [10]. Silicon-Photomultipliers (SiPMs) [12] extend dynamic range and provide multi-photon sensitivity and photon number resolution, through the parallelization of many SPADs with individual quenching resistors Their ensemble response can be either analog or digital and can be used to develop pixels with multiphoton capability, but they must still avoid saturation and they still need an analog readout.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
