A TECHNIQUE FOR CHANGING LIGHTING CONDITIONS IN AN HDTV IMAGE-BASED VIRTUAL STUDIO

摘要

A technique is described for changing the lighting conditions of the background video of an image-based virtual studio, in which high-definition background video reconstructed from information obtained from actual objects is synthesized with actual video of performers and other entities obtained with a camera. The lighting conditions of the background video are adjusted by controlling diffuse reflection so that they are compatible with the lighting conditions of the actual video. This reduces incongruity in the synthesized video and also makes it possible to obtain the background lighting required for the scene. A simple illumination model was created that limits the background video to an outdoor image and considers only the sun as the main light source together with ambient light and used to experimentally examine the effectiveness of this lighting-adjusting technique. Testing of an image-based virtual studio system constructed based on this technique demonstrated that background video can be generated under various lighting conditions.