DIBL : Dynamic Image Based Lighting

Abstract

The use of Image Based Lighting in computer graphics is increasing. Up till now it has shown that it is the best way of representing light captured from the real world for the lighting of computer generated imagery. Image based lighting has been successfully used to seamlessly integrate CGI in a Captured scene. The aim of this dissertation is to investigate novel techniques for adapting IBL to motion picture (video) for the lighting of any CGI which may be needed in the scene. The objective is to implement and test these techniques and to find which one is most successful. In the end the automated lighting for CGI which will be used in a scene is the ultimate goal. This dissertation beholds an extensive background in the field of CGI and film. It takes a close look at how CGI is created and embedded in a motion picture and the tools and techniques duly needed. It also analyzes related work in the field of IBL which is relevant with this project. Two novel techniques arc proposed. The first is based on the inverse-square relationship of light intensity with distance whilst the second is based on the sampling of light at different spatial positions and interpolating light sources from one point to the next. The idea of using the inverse-square relationship of light intensity with distance works only for scenarios where a scene is surrounded by light sources, where both the scene and light sources are static. It has been found out that this approach is not very useful as in film both light and scene tend to be dynamic. The second approach though has given promising results and was found applicable to dynamic scenes. This proves that the finally adopted technique is capable of representing dynamic lighting which is found in motion pictures. When reviewed by both a director and special effects supervisor from the most revolutionary company in the industry on the island, they both approved of the concept as a way of automating the lighting in a scene and think of it as convenient.