Photon-efficient imaging with a single-photon camera

TLDR

Reconstructing a scene’s 3D structure and reflectivity accurately with an active imaging system in low‑light conditions has wide‑ranging applications, but prior photon‑efficient approaches relied on raster‑scanning single‑pixel counters with ~10‑ps time tagging. The study proposes and demonstrates a depth‑and‑reflectivity imaging system using a single‑photon camera that produces high‑quality images from about one detected photon per pixel. The system employs a parallelized time‑to‑digital array with ~ns time‑tagging, and an array‑specific algorithm that refines coarsely binned photon detections by exploiting transverse smoothness and longitudinal sparsity to recover accurate depth and reflectivity. By overcoming the array’s coarse time resolution, the framework uniquely achieves high photon efficiency within a short acquisition time.

Abstract

Abstract Reconstructing a scene’s 3D structure and reflectivity accurately with an active imaging system operating in low-light-level conditions has wide-ranging applications, spanning biological imaging to remote sensing. Here we propose and experimentally demonstrate a depth and reflectivity imaging system with a single-photon camera that generates high-quality images from ∼1 detected signal photon per pixel. Previous achievements of similar photon efficiency have been with conventional raster-scanning data collection using single-pixel photon counters capable of ∼10-ps time tagging. In contrast, our camera’s detector array requires highly parallelized time-to-digital conversions with photon time-tagging accuracy limited to ∼ns. Thus, we develop an array-specific algorithm that converts coarsely time-binned photon detections to highly accurate scene depth and reflectivity by exploiting both the transverse smoothness and longitudinal sparsity of natural scenes. By overcoming the coarse time resolution of the array, our framework uniquely achieves high photon efficiency in a relatively short acquisition time.