Lambertianfördelning

Lambertianfördelning is a term used in computer graphics and optics to describe a surface that reflects light equally in all directions. This means that the brightness of the surface appears the same regardless of the viewing angle. Such surfaces are often referred to as perfectly diffuse reflectors.

The concept is named after Johann Heinrich Lambert, a Swiss mathematician and physicist who introduced the law of diffuse reflection in 1760. Lambert's cosine law states that the intensity of light reflected from a surface is proportional to the cosine of the angle between the surface normal and the direction of the incident light. For a Lambertian surface, this results in a uniform perceived brightness.

In practical terms, a Lambertian surface is an idealization. Most real-world surfaces exhibit some degree of specular reflection in addition to diffuse reflection. However, the Lambertian model is a useful approximation for many materials, such as matte paint, paper, and certain types of plastic. In computer graphics, rendering Lambertian surfaces is computationally efficient, making it a common choice for basic surface shading.

The mathematical representation of Lambertian reflection involves the radiance emitted by a surface element, which is constant regardless of the viewing direction. This simplicity makes it a foundational concept in understanding light interaction with surfaces.