title: Effect of the Temperature-Emissivity Contrast on the Chemical Signal for Gas Plume Detection Using Thermal Image Data.
abstract: Detecting and identifying weak gaseous plumes using thermal imaging data is complicated by many factors. These include variability due to atmosphere, ground and plume temperature, and background clutter. This paper presents an analysis of one formulation of the physics-based radiance model, which describes at-sensor observed radiance. The background emissivity and plume/ground temperatures are isolated, and their effects on chemical signal are described. This analysis shows that the plume's physical state, emission or absorption, is directly dependent on the background emissivity and plume/ground temperatures. It then describes what conditions on the background emissivity and plume/ground temperatures have inhibiting or amplifying effects on the chemical signal. These claims are illustrated by analyzing synthetic hyperspectral imaging data with the adaptive matched filter using two chemicals and three distinct background emissivities.
authors.affiliation: Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA. stephen.walsh@pnl.gov.
authors.forename: Stephen
authors.initials: S
authors.lastname: Walsh
authors.affiliation: Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA. lawrence.chilton@pnl.gov.
authors.forename: Larry
authors.initials: L
authors.lastname: Chilton
authors.affiliation: Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA. mark.tardiff@pnl.gov.
authors.forename: Mark
authors.initials: M
authors.lastname: Tardiff
authors.affiliation: Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, USA. candace.metoyer@pnl.gov.
authors.forename: Candace
authors.initials: C
authors.lastname: Metoyer
keywords: LWIR; Signal-to- Clutter Ratio; clutter; emissivity; hyperspectral; plumes; signal; temperature