Method for distinguishing between point and area targets

摘要

A method for distinguishing between point targets, particularly of missiles, and area targets, preferably representable by clouds, using a rigid electro-optical search sensor which, among other things, exhibits input optics, at least two detector elements arranged in the focal plane of the input optics on the image side, and a scanning and evaluating device interacting with the detector elements. Provision is to be made for filtering targets out of a noisy background and for distinguishing between point and area targets. This is done by evaluating the coherence condition for the light emanating from the point and area targets, in such a manner that when light with sufficient coherence is incident in the input optics, an interference pattern with an intensity distribution, consisting of equidistant strips, with a contrast of nearly one is generated which is characteristic for the point targets, and when light with inadequate coherence is incident, an interference pattern with an intensity distribution, consisting of equidistant strips, with reduced contrast is generated which is characteristic of the area targets. <IMAGE>