Auto Focus for Far Field Source Localization Using Emission Source Microscopy

Emission source microscopy (ESM) is a useful technique to locate emission sources contributing to far-field radiation. The focusing distance can affect image qualities and confuse the localization of radiation sources. This paper adopts the autofocus method in image processing to calculate the optimal focusing distance with the best image quality. The proposed methodology was verified using a numerical simulation as well as a measurement. Also, calculating the contrast of a local source region shows better noise immunity. This autofocus algorithm in ESM can easily obtain the exact distance between the radiation sources and the scanning plane and can be used to localize sources in 3D space.