Predicting Important Photons for Energy-Efficient Single-Photon Videography

Single-photon avalanche diodes (SPAD) detect individual photons with fine temporal resolutions, enabling capabilities like imaging in near-total darkness, extreme dynamic range, and rapid motion. Due to these capabilities, and coupled with the recent emergence of high-resolution (> 1MP) arrays, SPADs have the potential to become workhorses for computer vision systems of the future that need to operate in a wide range of challenging conditions. However, SPADs' sensitivity comes at a high energy cost due to the underlying avalanche process, which consumes substantial energy per detected photon, limiting the scalability and practicality of high-resolution SPAD arrays. To address this, we propose approaches to predict and sample only the most salient photons for a given vision task. To this end, we design computationally lightweight photon-sampling strategies that allocate energy resources for detecting photons only in areas with significant motion and spatial variation, while continually adapting to changing signals. We demonstrate the effectiveness of the proposed methods in recovering comparable video to a fully-sampled SPAD capture using only a small fraction of the photons (up to 10× fewer), across diverse real-world scenes with motion, high dynamic range, and varying light conditions.