Dithered Depth Imaging for Single-Photon Lidar at Kilometer Distances

Abstract

Depth imaging using single-photon lidar (SPL) is crucial for long-range imaging and target recognition. Subtractive-dithered SPL breaks through the range limitation of the coarse timing resolution of the detector. Considering the weak signals at kilometer distances, we present a novel imaging method based on blending subtractive dither with a total variation image restoration algorithm. The spatial correlation is well-considered to obtain more accurate depth profile images with fewer signal photons. Subsequently, we demonstrate the subtractive dither measurement at ranges up to 1.8 km using an array of avalanche photodiodes (APDs) operating in the Geiger mode. Compared with the pixel-wise maximum-likelihood estimation, the proposed method reduces the depth error, which has great promise for high-depth resolution imaging at long-range imaging.