High fidelity thermal modeling and other recent advancements toward realistic spectral scene generation of vegetated areas

Vehicles concealed in highly-cluttered, vegetated scene environments pose significant challenges for passive sensor systems and algorithms. System analysts working hypersectral exploitation research require and at-aperature simulation capability that allows them to reliably investigate beyond ther highly-limited scenarios that expensive field data sets provide. To be useful to the analyst, such a simulation should address the following requirements: (1) the ability to easily generate scene representations for abritrary Earth regions of tactical interests; (2) the ability to represent scene components, like terrain, trees and bushes, to an extremely high spatial resolution for calculation of accurate multiple spectral reflections, occlusions and shadowing; (3) the ability to stimulate the 3D scene with realistic natural irradiances for arbitrary model atmospheres; (4) the ability to appropriately integrate improving, rigorous thermal, spectral signature and atmospheric propogation models; (5) the ability to effectively render at-apurature hyperspectral data sets in a reasonable run-time. herein the authors describe their continuing work toward a comprehensive ray-tracer-based simulation archetecture and prototype capability that addresses these requirements, with emphasis on new techniques for high fidelity thermal modeling, and recent improvements in atmospherically scattered irradiance modeling, manmade light source modeling, and GIS-based database generation, including automated material classification of terrain and scene elements.