Processing system and method for enhancing image data

Abstract

A non-linear digital filter system for image data or other signal data suppresses undesirable noise while enhancing significant characteristics of the data. Data elements in a neighborhood (window) defined around and including an input data element are classified into characteristic classes based on their parameter value range. The class with the maximum population is selected as most representative of the neighborhood. A data value associated with that class is chosen as the output of the filter for the input data element around which the neighborhood is defined, to thereby form a plurality filter. As an alternative, the class holding more than half the data elements in the neighborhood is chosen as most representative, to form a majority filter. In case there is no class containing more than half the elements in a neighborhood, the output of the filter equal the value characteristic of the class in which the input pixel itself falls. In a further heterogeneity filter version, a data element for whose neighborhood there is no majority class is replaced by a '1'; a pixel for whose neighborhood there is a majority class is replaced by a '0'. In the case of image data, the '1' value may represent a black intensity or a white intensity, in which case the '0' represents the opposite intensity.