Hypertools in Image and Volume Visualization

This paper describes our experience in image and volume visualization at the Lawrence Livermore National Laboratory. After an introduction on visualization issues, we present a new software approach to the analysis and visualization of images and volumes. The efficiency of the visualization process is improved by letting the user combine small and reusable applications by the means of a machine-independent interpreted language such as Tcl/Tk. These hypertools can communicate with each other over a network, wihich has a direct impact on the design of graphical interfaces. We first describe the implementation of a flexible gray-scale image widget that can handle large data sets, provides complete control of the color palette, and allows for manual and semi-interactive segmentation. This visulaization tool can be embedded in a data-flow image processing environment to assess the quality of acquisition, preprocessing and filtering of raw data. This approach combines the simplicity of visual programming with the power of a high-level interpreted language. We show how hypertools can be used in surface and volume rendering and how they increase the interaction efficiency by performing complex or tedious tasks automatically. One biomedical application is presented.