SPATIAL FILTERS,

Several spatial filters are discussed whose input comes from the image plane of an optical imaging system. These filters are for the purpose of detecting a localized intensity source imbedded in a confusing background of similar sources. Three of the filters have two-dimensional static pictures as both input and output. Two of these are called polynomial filters while the third is of a general type. A fourth filter, called a decision filter, has a yes or no output with regard to the presence or absence of the localized intensity source. A remarkable connection between the decision filter and the general type is shown. Author