1. A localization method comprising: acquiring a first photon position map with a single-photon detector, the first photon position map containing position data for a first plurality of photons originating from a first light source; assigning with a computer a first probability distribution function to each of the first plurality of photons in the first photon position map originating from the first light source; and determining with the computer a location for each of the first plurality of photons from the respective first probability distribution function.