Image-based lighting (IBL) is the process of illuminating scenes and objects (real or synthetic) using images of light from the real world. This is in contrast to using only direct light sources such as point lights or spotlights which are more localized. For more information about direct light sources, see Types of Lights [Direct Illumination].
Image-based lighting is derived from the reflection-mapping technique in which panoramic images are mapped onto a dome or sphere and the lighting characteristics of the surrounding environment are reflected in the shiny surfaces of objects when rendering the scene. For more information about reflection mapping, see Reflection/Environment Maps [Texturing].
Image-based lighting techniques can produce realistic rendered appearances of objects and can be an effective tool for integrating computer graphics objects into real world scenes.
You can also "reverse" the image-based lighting technique by generating a rig of conventional lights based on the lighting in a source image.
