A Point-Spread Function (PSF) is a description of the response of an optical system (such as a telescope) to incoming light from a point, consisting of a mathematical function describing the light-pattern expected on the focalplane.plane. An example would be a function that describes an Airy Disk. There are theories associating specific mathematical functions to particular Aperture shapes (e.g., rectangles, slits, circles) and sizes. PSF Subtraction (for Point Spread Function Subtraction) is post-processing designed to sharpen images by nullifying part of the Airy Disk's etc., e.g., from multiple images. Referenced by: PSF Fitting Speckle Suppression |