Steven Richtsmeier (Spectral Sciences, Inc.), Robert Sundberg (Spectral Sciences, Inc.), Raymond Haren (AFRL/SNJT), Frank O. Clark (AFRL/VSBT)
Keywords: Astronomy
Abstract:
Full optical spectrum (UV to LWIR) hyperspectral scene simulation provides an accurate, robust, and efficient means for algorithm validation and sensor design trade studies. This paper reviews the development of a first-principles, high-fidelity HSI/MSI image simulation capability, dubbed MCScene, which is based on a Direct Simulation Monte Carlo techniques and demonstrates how the model can be used for sensor design trade studies. Basic features of the model will be discussed and illustrated with a spectral simulation for a prototype hyperspectral sensor. Sample calculations presented in this paper include long wave infrared spectrum simulations for a region of Mars under varying solar illuminations and atmospheric conditions. Source information for simulations will be based on mission data where available. Such simulations can be important for gauging the effects of the Martian atmosphere on mineral determination by orbiting multispectral imagers, for example.
MCScene incorporates all optical effects important for solar-illuminated and thermal scenes, including molecular and aerosol scattering, absorption and emission, surface scattering and emission with material-dependent bidirectional reflectance distribution functions (BRDFs), multiple scattering events, surface adjacency effects, and scattering, emission and shading by clouds, for arbitrary solar illumination and sensor viewing geometries. The world of the simulation is a cube, nominally 50 km on a side that encloses a user-definable atmosphere containing molecular species, aerosols, and clouds, and a terrain representing the ground. The sensor spatial and spectral resolution, its location, and the viewing angle are also specified. The field-of-view (FOV) is a finely gridded inner region within the 50 km x 50 km ground area; nominally, it is a 10 km square gridded with 1m2 surface pixels. The technique supports surface facets with arbitrary elevations and normals. A particular strength of MCScene is that a simulation can be data driven. Terrain information can be imported from USGS digital elevation maps or other topographical maps. Surface reflectance or emissivity/temperature maps can be derived from collected imagery, thus incorporating natural spectral and spatial texturing into a simulation.
Date of Conference: September 10-14, 2006
Track: Astronomy