Layers for Effective Volume Rendering

Abstract

A multi-layer volume rendering framework is presented. The final image is obtained by compositing a number of renderings, each being represented as a separate layer. This layer-centric framework provides a rich set of 2D operators and interactions, allowing both greater freedom and a more intuitive 2D-based user interaction. We extend the concept of compositing which is traditionally thought of as pertaining to the Porter and Duff compositing operators to a more general and flexible set of functions. In addition to developing new functional compositing operators, the user can control each individual layer s attributes, such as the opacity. They can also easily add or remove a layer from the composition set, change their order in the composition, and export and import the layers in a format readily utilized in a 2D paint package. This broad space of composition functions allows for a wide variety of effects and we present several in the context of volume rendering, including two-level volume rendering, masking, and magnification. We also discuss the integration of a 3D volume rendering engine with our 2.5D layer compositing engine.