Image-Based Lighting (IBL) has become a very popular approach in computer graphics. In essence IBL is based on capturing the
illumination conditions in a scene in an omni-directional image, called a light probe image. Using the illumination information
from such an image virtual objects can be rendered with consistent shading including global illumination effects such as color
bleeding.
Rendering with light probe illumination is extremely time consuming. Therefore a range of techniques exist for approximating
the incident radiance described in a light probe image by a finite number of directional light sources. We describe two such
techniques from the literature and perform a comparative evaluation of them in terms of how well they each approximate the
final irradiance. We demonstrate that there is significant difference in the performance of the two techniques.
Keywords Augmented Reality - Image-Based Lighting - median cut - irradiance - real-time rendering - directional light sources