The dependence of target discriminability on systematic and random variations in recorded radiance

Abstract

Radiance reflected or emitted from a ground target exhibits an angular anisotropy which is wavelength dependent. While some empirical or modelling corrections may be made to reduce the impact of systematic effects upon target discrimination, no correction may be made for random variations in ground reflectance or emittance, nor for random variations in irradiance on the ground (optical reflective case) and in atmospheric transmission and backscallcr. A simple case in the optical-reflective region is considered, in order to demonstrate the dependence on scan angle (for a given Sun angle) of the effect of random variations on the discriminability of two ground targets partly obscured by a varying amount of unresolved cloud.