XMM-Newton Science Analysis System


imgrad (tools-1.63) [xmmsas_20070308_1802-6.6.0]

Meta Index

imgrad

Ian Stewart (SSC/LUX, ims@star.le.ac.uk)

July 22 2002

Abstract:

This task approximates the gradient at each pixel of an image by doing least-squares fitting of a plane to the 3x3 array of values centred on each pixel.