"Annulus Clutter Filter" for Infrared Surveillance Sensors

Improved clutter suppression in Infrared Surveillance Sensors is acheived by reprocessing the data fields in the vicinity of detected Targets to distinquish between true Target responses and leak through Clutter responses that arise from clutter "Microgradients" hidden well below the primary clutter flucuations. The clutter "Microgradients" may exhibit rapid spatial changes in gradient properties; determined by processing the data values in a small radius Annulus centered on each detected Target position. The proposed Phase 1 program compares alternative algorithms for effectiveness of clutter suppression and complexity of implementation. The proposed "Annulus Clutter Filter" operates on local data fields and is largely independent of the global Wiener spectrum of the clutter. Amplitude distributions of the clutter errors are expected to be non-gaussian,so a new definition of Signal-to Noise Ratio (SNR|,and related "Process Gain', is advocated. Infrared sensors used in Military and Commercial applications will be less affected by background clutter, thereby giving improved Target detection and improved Target measurements accuracy.