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1. Original volume losslessly compressed to 54 MB (ratio 2.7:1). 2. Rendered volume using 11% of full data size (16 MB, ratio 9:1). 3. Rendered volume using 1.4% of full data size (2.0 MB, ratio 72:1). 4. Rendered volume using 0.3% of full data size (0.44 MB, ratio 326:1). Figure 1: Data reduction effects using Adaptive Decompression with our High Quality(More)
This article presents two new parametric models of the <i>Bidirectional Reflectance Distribution Function</i> (BRDF), one inspired by the Rayleigh-Rice theory for light scattering from optically smooth surfaces, and one inspired by micro-facet theory. The models represent scattering from a wide range of glossy surface types with high accuracy. In(More)
Direct Volume Rendering (DVR) is of increasing diagnostic value in the analysis of data sets captured using the latest medical imaging modalities. The deployment of DVR in everyday clinical work, however, has so far been limited. One contributing factor is that current Transfer Function (TF) models can encode only a small fraction of the user's domain(More)
We present a general, proxy-based approach to volume haptics founded upon the notion of 'haptic primi-tives'. Haptic modes each representing a different aspect of volumetric data, are created by defining sets of haptic primitives which reflect the local properties of the data. The proxy position for every time-frame in the hap-tic loop is found by balancing(More)
In this paper we present an in situ evaluation of a haptic system, with a representative test population, we aim to determine what, if any, benefit haptics can have in a biomolecular education context. We have developed a haptic application for conveying concepts of molecular interactions, specifically in protein-ligand docking. Utilizing a semi-immersive(More)
Multi-dimensional Transfer Functions (MDTFs) are increasingly used in volume rendering to produce high quality visualizations of complex data sets. A major factor limiting the use of MDTFs is that the available design tools have not been simple enough to reach wide usage outside of the research context, for instance in clinical medical imaging. In this(More)
Direct Volume Rendering has proved to be an effective visualization method for medical data sets and has reached wide-spread clinical use. The diagnostic exploration, in essence, corresponds to a tissue classification task, which is often complex and time-consuming. Moreover, a major problem is the lack of information on the uncertainty of the(More)
This paper presents a novel technique to efficiently compute illumination for Direct Volume Rendering using a local approximation of ambient occlusion to integrate the intensity of incident light for each voxel. An advantage with this local approach is that fully shadowed regions are avoided, a desirable feature in many applications of volume rendering such(More)