Editing Super-resolution imaging (section)

====Sub-pixel image localization====
The location of a single source can be determined by computing the "center of gravity" ([[centroid]]) of the light distribution extending over several adjacent pixels (see figure on the left). Provided that there is enough light, this can be achieved with arbitrary precision, very much better than pixel width of the detecting apparatus and the resolution limit for the decision of whether the source is single or double.  This technique, which requires the presupposition that all the light comes from a single source, is at the basis of what has become known as [[super-resolution microscopy]], e.g. [[stochastic optical reconstruction microscopy]] (STORM),  where fluorescent probes attached to molecules give [[Nanoscopic scale|nanoscale]] distance information.  It is also the mechanism underlying visual [[hyperacuity]].<ref>{{cite journal | last1 = Westheimer | first1 = G | year = 2012 | title = Optical superresolution and visual hyperacuity | journal = Prog Retin Eye Res | volume = 31 | issue = 5| pages = 467–80 | doi=10.1016/j.preteyeres.2012.05.001| pmid = 22634484 | doi-access = free }}</ref>