Illuminations models

Illumination Models & Surface-Rendering Methods

•          Illumination model or a lighting model  is the model for calculating light intensity at a single surface point.

•          Surface rendering is a procedure for applying a lighting model to obtain pixel intensities for all the projected surface positions in a scene.

Given the parameters:

•          the optical properties of surfaces (opaque/transparent, shiny/dull, surface-texture);

•          the relative positions of the surfaces in a scene;

•           the color and positions of the light sources;

•          the position and orientation of the viewing plane.

Illumination models calculate the intensity projected from a particular surface point in a specified viewing direction.

•          Basic Illumination Models

      Ambient Light

      Diffuse Reflection

      Specular Reflection & Phong Model

      Combine Diffuse & Specular Reflections with Multiple Light Sources

•          When we view an opaque nonluminous object, we see reflected light from the surfaces of the object.

•          The total reflected light is the sum of the contributions from light sources and other reflecting surfaces in the scene.

•          Light sources = light-emitting sources.

•          Reflecting surfaces = light-reflecting sources.