Approximated View Reconstruction Using Precomputed ID-Bitfields

Abstract

A technique is presented to construct arbitrary views of a model by using previously computed views. The technique is simple to implement, completely general for polygonal models and can be used within object hierarchies or scene graphs. During a preprocessing step images of a model are taken from different viewpoints. These images are saved using long bitfields (ID-bitfields) which encode the visibility information according to an array of the model’s primitives used as the base for the bitfield. These ID-bitfield encodings, together with the primitive array, are then used by a viewer which selects and joins them to provide an approximated (not conservative) reconstruction of the visible elements of the object for a new viewpoint. The technique implicitly performs occlusion culling, since a minimal set of visible polygons is the result of the reconstruction. Results show how interaction can be improved when working with high depth complexity models. Satisfactory reconstructions are achieved by taking as few as 25 images around an object. This paper suggests how the technique can be extended to other applications such as virtual walkthroughs and visualization of non-realistic images, and how graphics libraries and hardware could be enhanced by allowing the application to pass an ID-bitfield. Key words: view reconstruction, interactive display, visibility preprocessing, occlusion culling, polygon reduction.