Minimum difference processor

Abstract

A process for reducing background clutter of a scene, and isolating an object of interest. The process includes calculating a minimum output from a plurality of appropriately configured anti-median filters representing a minimum difference processor (MDP) filter. In a first embodiment, the MDP filter includes a (5.times.5) matrix of elements wherein each element has an intensity value representation of the scene. A first anti-median filter array is configured as a horizontal array of 5 pixel elements in which the center element of the matrix is the center element of the horizontal array. A median value of the 5 elements of the horizontal array is determined, and is subtracted from the value of the center element to determine an anti-median value of the horizontal array. The same process is performed for a vertical 5 element anti-median array, and two diagonal 5 element anti-median arrays, all including the center element of the matrix as the center common element of the arrays. The lowest anti-median value is then outputted as the output of the MDP filter. In a second embodiment, the values of the remaining elements of the matrix which were not included in any of the horizontal, vertical or diagonal arrays described above are subtracted from the center element of the matrix. The lowest value from the group of anti-median values together with the remaining subtracted values is outputted from the MDP filter. This enables the background clutter of the scene to be substantially suppressed or eliminated.