Universal RTM

Hapke and Shkuratov Spectral Modeling

Hapke Radiance-Factor Model

This implementation applies the Hapke porosity correction K(φ) from the solid filling factor φ, which is constrained to 0-0.52. CBOE is only a few degrees wide and has a shape similar to the broader SHOE, approximately 20 degrees wide. SHOE is therefore used and CBOE is fixed at zero; SHOE can also help reproduce the CBOE contribution. See Hapke et al. (2012).

The reported reflectance is radiance captured by the spectrometer divided by the incident solar irradiance spectrum divided by π, equivalent to an ideal Lambertian reference radiance.

Mixture Spectrum

Observed mixture reflectance or Single Scattering Albedo. You can select multiple files; each file becomes one or more spectra.

Endmember Library

Known endmember spectra used by the selected workflow. They may be Single Scattering Albedo spectra or Optical Constants depending on the model path.

Model Parameters
Viewing Geometry All angles are in degrees.
Using the values shown in the equation.
Known or Prior Input Filling Factor φ: 0-0.52 Fixed: CBOE = 0
R = K() ωave 4 cos() cos() + cos() { [1 + B( , )] P ( , , ) + H( / ) H( / ) - 1 } S( , , , )
Image Input
Select one GeoTIFF, or select the metadata (.hdr or .lbl) and paired binary file together. Paired files must share a basename. All angles are in degrees.
Image Wavelength

No image selected. Wavelength metadata will be checked automatically.

Load an image to customize its wavelength range.

Endmember Library
Model and Processing Settings
Spatial resampling is applied identically to reflectance and viewing-angle images.