Fast visualization of volume emissions using conservative subdivision
A hierarchical volume rendering algorithm is presented. Volume emissions in optically thin media are considered. A sparse hierarchical wavelet-based representation of the directional volume emission rate function is constructed top-down and then projected onto the image plane. This makes the algorithm fast, since the number of operations is proportional to the number of coefficients in the representation. Also, the sparsity minimizes the algorithm's memory requirement. The representation is constructed using conservative subdivision, making the projection onto a lower-dimensional representation trivial. The error is controlled by a threshold parameter, allowing a direct trade-off between speed and accuracy. The algorithm is especially well suited when the directional volume emission rate is computationally expensive to evaluate, since the sparse representation minimizes the number of function evaluations for rendering a volume with a specified accuracy. Since a sparse oct-tree is constructed for a specific view point the method is best suited to situations where an image is to be generated from one view point. (C) 2003 IMACS. Published by Elsevier B.V. All rights reserved.
subdivision volume rendering oct-tree