Call for Papers
Part IV: Volume Rendering
Voxels versus Polygons: A Comparative Approach for Volume GraphicsDirk Bartz and Michael MeiBner
The decision to use either the Direct Volume Rendering paradigm or the Indirect Volume Rendering paradigm to visualise a volume dataset is a topical question in Volume Graphics. Unfortunately, it seems that this question has not been sufficiently addressed so far and is not easy to answer.
In this chapter, we discuss some of the advantages and disadvantages of one candidate for each of these paradigms; Ray Casting for Direct Volume Rendering and Marching Cubes for Indirect Volume Rendering. The discussion is based on two Cartesian grid scalar data fields, a CT scan of a lobster -- immersed in resin, and a MRI scan of a human head. These datasets have interesting properties which show different features using different Volume Rendering techniques. Two measurements are considered for our discussion; visual quality and the consumption of resources, such as time and memory.
Fast Multi-Resolution Volume RenderingYang Yuting, Lin Feng and Seah Hock Soon
This chapter presents a volume rendering algorithm exerting the shear-warp of the viewing transformation on a multi-resolution volume data set. A homogeneous region within given error-tolerance in the volume is encoded as a run-length. In the parallel projection which has already been simplified by shearing, the number of elements to be processed can be further reduced due to the homogeneity of the region. Our algorithm supports full interactions. It is especially suitable for discovering the information in a new volume data set.
High-Quality Volume Rendering using Seed Filling in View LatticeJarkko Oikarinen, Rami Hietala and Lasse Jyrkinen
Many new acceleration techniques for volume rendering have been developed during the last ten years. Seed filling in view lattice is an acceleration technique that speeds up volume rendering by avoiding the processing of empty voxels that do not contribute to the final image. Our previously published results used the template method as a traversal lattice. However, the creation of high-resolution high-quality views requires a denser view lattice than single template can provide. This can be obtained by using multiple templates. In this chapter we use multiple templates in conjunction with the seed filling acceleration technique to calculate the view lattice in higher resolution. The algorithm is implemented on a general purpose personal computer (266 MHz Pentium II). We measure the rendering times to evaluate the performance impact, and show how the image quality is improved.
Extending Hypertextures to Non-Geometrically Definable Volume DataRichard Satherley and Mark W. Jones
Texture mapping is an extremely powerful tool for the addition of surface detail to an object. This chapter aims to introduce the field of three dimensional texture mapping, in terms of "solid textures" and "hypertextures". The second half of the chapter shows how the hypertexture paradigm can be extended, with the use of "distance transforms", to incorporate non-geometrically definable datasets.
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