In Shafer’s dichromatic reflection model,
[Shafer, S.A]
Using color to separate reflection components
Color: Research and Application, Volume 10, Issue 4, pp. 210-218, December, 1985. scene
radiance
In radiometry, radiance is the radiant flux emitted, reflected, transmitted or received by a given surface, per unit solid angle per unit projected area. Radiance is used to characterize diffuse emission and reflection of electromagnetic radiatio ...
has two components:
:
: ''λ'' is the
wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tr ...
,
: ''c''
b is the body (
diffuse
Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...
) reflected component,
: ''c''
s is the surface (interface) (
specular
Specular reflection, or regular reflection, is the mirror-like reflection of waves, such as light, from a surface.
The law of reflection states that a reflected ray of light emerges from the reflecting surface at the same angle to the surf ...
) reflected component,
: ''m''
b and ''m''
s are
scale factor
In affine geometry, uniform scaling (or isotropic scaling) is a linear transformation that enlarges (increases) or shrinks (diminishes) objects by a '' scale factor'' that is the same in all directions. The result of uniform scaling is simila ...
s depending on
illumination, view directions and surface orientation.
Separation algorithm
BREN (body reflection essence-neuter) model based
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.
[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.
References
Applied mathematics
Optics
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