Diffuse reflection

Diagram of diffuse reflection

Diffuse reflection is the reflection of light from an uneven or granular surface such that an incident ray is seemingly reflected at a number of angles. It is the complement to specular reflection. If a surface is completely nonspecular, the reflected light will be evenly spread over the hemisphere surrounding the surface (2π steradians).

The most familiar example of the distinction between diffuse and specular reflection would be matte and glossy paints as used in home painting. Matte paints have a higher proportion of diffuse reflection, while gloss paints have a greater part of specular reflection. Most objects that one sees are visible due to diffuse reflection. Light scattering from the surfaces of objects is our primary mechanism of physical observation.^[1][2]

Diffuse interreflection is a process whereby light reflected from an object strikes other objects in the surrounding area, illuminating them. Diffuse interreflection specifically describes light reflected from objects which are not shiny or specular. In real life terms what this means is that light is reflected off non-shiny surfaces such as the ground, walls, or fabric, to reach areas not directly in view of a light source. If the diffuse surface is colored, the reflected light is also colored, resulting in similar coloration of surrounding objects.

Three bi-directional diffuse reflection (BRDF) models

In 3D computer graphics, diffuse interreflection is an important component of global illumination. There are a number of ways to model diffuse interreflection when rendering a scene. Radiosity and photon mapping are two commonly used methods.

See also

Computer graphics portal

• Optics
• Diffuser
• Reflectivity
• Lambertian reflectance
• Oren–Nayar diffuse model

References

1. ^ Kerker, M. (1909). The Scattering of Light. New York: Academic. 
2. ^ Mandelstam, L.I. (1926). "Light Scattering by Inhomogeneous Media". Zh. Russ. Fiz-Khim. Ova. 58: 381.