Advance shading--basis (radiometric measurement)

Measurement of emissivity (radiometry)

"Real time rendering" in this chapter to say a lot of lighting aspects of the physical terminology, do not know how to translate. Later on Wikipedia see this table, clear a lot (here w is the meaning of watt, the unit is the Joule, the energy, and so on wavelength multiplied Planck constant) http://zh.wikipedia.org/wiki/%E5%BC%B7%E5%BA%A6_ (%e7%89 %A9%E7%90%86):

The definition of surface degree is:

There are two more visual explanations of emissivity, such as:

The first, which is the representation of the second graph: the ratio of irradiance and w that all photons in the w angle impact to the surface of the object.

The second explanation is the intensity density of the radiation on the unit area.

The radiation rate is calculated by having an equation that contains five variables. Two of them are directional vectors. The basic idea is to think of the screen as a set of directions that contains a lot of rays, and then calculate the color by pixel.

　　

Advance shading--basis (radiometric measurement)