Single-photon avalanche diodes (SPADs) are an emerging image sensor technology. Due to their unique ability to precisely time-tag individual photons, SPADs have great potential for high-resolution long-range LiDAR systems. However, due their peculiar image formation model, extreme ambient light incident on a SPAD LiDAR causes severe distortions (called pile-up) leading to large depth errors.

Currently, these distortions are avoided by artificially lowering the incident photon flux. However, this has the undesirable side-effect of lowering the signal-to-noise ratio. We address the following basic question: What is the optimal photon flux that a SPAD-based LiDAR should be operated in? Our theoretical analysis leads to a simple, practical, closed form mathematical expression that depends on the strength of the ambient light.

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Published by Wision