Interactive transfer function design on large multiresolution volumes

Interactive transfer function design techniques seek to leverage user knowledge to facilitate the discovery of data salience. In this process, interactive volume rendering is typically a necessity. Interactive volume rendering of large-scale data on workstations is often accomplished through the use of level of detail techniques, prioritizing information deemed to be salient over information deemed to be unimportant. If salience is not known a priori, and interactive transfer function design techniques that depend on volume rendering are to be applied to large-scale data using level of detail selection, then there is a cyclic dependency. Techniques must be applied that can support simultaneous development of salience both for the transfer function design technique and the level of detail selection technique. Building on recent work in LOD selection, we propose an interactive transfer function design technique that enables incremental salience discovery to support simultaneous construction of transfer functions and LOD selections on large-scale data.