Long-range depth imaging using time-correlated single-photon counting

Active, three-dimensional long-range imaging has varied applications in a number of disciplines, including manufacturing, environmental sensing and defence. Common constraints often include low average and peak illumination powers to ensure eye-safety, making the potentially high sensitivity of the single-photon counting technique a distinct advantage. We present a scanning time-of-flight imager based on high repetition-rate (>MHz) pulsed illumination and a silicon single-photon detector. In advanced photon-counting experiments, we recently employed the system for unambiguous range resolution at several kilometres target distance, multiple-surface resolution based on adaptive algorithms, and a cumulative data acquisition method that facilitates detector characterisation and evaluation. This article reviews these achievements and identifies multi-spectral imaging as a possible future application. © 2010 SPIE.