| Radiosity method, based on thermal engineering theory, has become the most effective technique used in global illumination of diffuse environments in realistic image synthesis. This thesis presents a new mesh refinement algorithm based on shadow edge detection for the radiosity method. Refining mesh along shadow boundaries can yield radiosity solutions that are more accurate both visually and numerically. Instead of determining the shadow boundary by pure geometric refinement of a mesh, this new algorithm resolves shadow details by using a modified hierarchical meshing strategy and edge detection image processing techniques. In the algorithm, shadow boundaries on a surface are approximated by a link of shadow edges that are detected on the mesh of elements of this surface. No sophisticated shadow boundary representation method is needed to keep mesh elements conformed. Another advantage of this approach comes from a possibility of implementation in hardware parts of the algorithm. Successful experimental work has been conducted using the new method, and the results are encouraging. |
