Soil signature simulation in the thermal infrared

Abstract

Soil emissivity signatures were constructed using the digital imaging and remote sensing image generation (DIRSIG) model and Blender three-dimensional (3-D) graphic design software. Using these tools, the geometry, radiometry, and chemistry of quartz were exploited to model the presence of particle size effects in the thermal spectra of disturbed soil. Using the physics engines within the Blender 3-D graphic design software, a physical representation of a granular soil scene was created. Chemical and optical properties of pure quartz were assigned to particles in the scene based on particle size. The spectral signature of disturbed soil was modeled by the physical mixture of small fine particles (50 μm diameter) and larger grains (500 μm diameter). The study demonstrated that by combining realistic target geometry and spectral measurements of pure quartz, emissivity of complex soil mixtures could be modeled without functional data fitting or rigorous analysis of material dynamics.