ABSTRACT
In many computer graphics applications we wish to augment virtual objects with images representing a real environment (sky, city, etc.). In order to provide the illusion that the virtual objects are parts of the real scene, the illumination of the environment should be taken into account when rendering the virtual objects [Debevec 98,Kollig and Keller 03]. Since the images representing the environment lack depth information, we usually assume that the illumination stored in these images comes from far surfaces. This means that the illumination of the environment is similar to directional lights, it has only directional characteristics, but its intensity is independent of the location of the illuminated point.
