Image Classification at Low Light Levels

Abstract

At low light levels, a two-dimensional photon-counting detector may be employed to provide an estimate of the cross-correlation between an input image and a set of reference images stored in computer memory. Recent experiments1,2 have demonstrated that in many cases, a small number of detected photoevents is sufficient to yield reliable image recognition. The binary nature of the photon­limited input, coupled with the high rate of operation afforded by commercially available detectors, leads to recognition times on the order of tens of milliseconds.