Cramer-Rao bounds for long-wave infrared gaseous plume quantification

Abstract

The central parameter in the quantification of chemical vapor plumes via remote sensing is the mean concentration-path length (CL) product, which can be combined with scene geometry information to provide estimates of the absolute gas quantity present. We derive Cramer-Rao lower bounds on the variance of an unbiased estimator of CL in concert with other parameters of a nonlinear radiance model. These bounds offer a guide to feasibility of CL estimation that is not dependent on any given algorithm. In addition, the derivation of the bounds yields great insight into the physical and phenomenological mechanisms that control plume quantification, which we illustrate with examples representing a variety of experimental scenarios.