# Dichromatic reflectance model

In Shafer’s dichromatic reflection model[1], scene radiance has two components:

${\displaystyle L(\lambda )=m_{\mathrm {b} }c_{\mathrm {b} }(\lambda )+m_{\mathrm {s} }c_{\mathrm {s} }(\lambda )}$
λ is the wavelength,
cb is the body reflected component,
cs is the surface (interface) reflected component,
mb and ms are scale factors depending on illumination, view directions and surface orientation.

## Separation algorithm

### BREN (body reflection essence-neuter) model based[2]

Body essence is an entity invariant to interface reflection, and has two degrees of freedom. The Gaussian coefficient generalizes a conventional simple thresholding scheme, and it provides detailed use of body color similarity.[2]

## References

1. ^ Shafer, S.A. Using color to separate reflection components Color: Research and Application, Volume 10, Issue 4, pp. 210-218, December, 1985.
2. ^ a b C. Je and H.-M. Park. BREN: Body Reflection Essence-Neuter Model for Separation of Reflection Components. Optics Letters, Volume 40, Issue 9, pp. 1940-1943, May 1, 2015.