Multispectral Detection of Dim Slightly Extended Targets in Heavy Clutter

摘要

The spectral signature of a target is typically unknown apriori ecause ofits dependence upon environmental conditions (e.g., sun angle, atmospheric attenuation and scatteirng), factors effecting the reflectivity and emissivity of the target's surface (dirt, dust, water, paint, etc.) and recent operating history (hot or cold engine, exhaust parts, wheels or tracks, etc.). Because of the high variability of the spectral signature of a target, multispectral detection typically detects spectral anomalies. For example, the canopy of a helicopter hovering in front of tree clutter may glint in the midwave infrared band while the reststrahlen spectral feature of the fuselage paint occurs in the longwave infrared band. Both of these are spectral anomalies relative to the tree clutter.