Visibility Sorting and Compositing Without Splitting for Image Layer Decompositions

We present an efficient algorithm for visibility sorting a set of moving geometric objects into a sequence of image layers which are composited to produce the final image. Instead of splitting the geometry as in previous visibility approaches, we detect mutual occluders and resolve them using an appropriate image compositing expression or merge them into a single layer. Such an algorithm has many applications in computer graphics; we demonstrate two: rendering acceleration using image interpolation and visibility-correct depth of field using image blurring. We propose a new, incremental method for identifying mutually occluding sets of objects and computing a visibility sort among these sets. Occlusion queries are accelerated by testing on convex bounding hulls; less conservative tests are also discussed. Kd-trees formed by combinations of directions in object or image space provide an initial cull on potential occluders, and incremental collision detection algorithms are adapted t...

• Type: Conference
• Year: 1998
• Where: SIGGRAPH
• Authors: John M. Snyder, Jed Lengyel
• Keywords: Computer Graphics, Image Compositing Expression, Mutual Occluders, SIGGRAPH 1998, Single Layer