a terrorist group of radical Palestinians who split with al-Fatah in 1967 but now have close relations with al-Fatah; staged terrorist attacks against Israel across the Lebanese border
Point spread function A measure of the geometrical performance of an optical system Defines the apparent shape of a point target as it appears in the output image A plot of illuminance of the image as a function of distance in the image plane See also: MTF, OTF, LSF