Inverse Transport Solutions for Identifying Hidden Objects.

摘要

A research program to develop and numerically test inverse methods for identifying the absence or presence of an object obscured within or behind a low visibility atmosphere or smoke cloud was completed. Time-dependent and time-independent methods were developed for simultaneously estimating the optical depth of an object and the albedo of its surface from backscattered irradiance measurements, and time-independent algorithms were also developed for estimating the optical depth of the atmosphere when the albedo of the hidden surface is known. The inverse transport methods are based on the radiative transfer equation for analyzing multiply-scattered radiation in a cloud. The project consisted of four components: a) calculations of the effects on the lidar signal of a large flat object located at variable depths behind an obscuring cloud, b) calculations of the effects on the lidar signal of a small spherical object located at variable depths within an obscuring cloud, c) development of an analytically-based iterative method to estimate from the time-independent backscattered irradiance the albedo and optical depth of a large flat object located at variable depths behind an obscuring cloud, and d) development of approximate algorithms to estimate from the time-independent backscattered irradiance the albedo and optical depth of a large flat object located at variable depths behind an obscuring cloud. Keywords: Remote sensing; Radiative transfer. (kr)