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Hardware-accelerated, high-quality rendering based on trivariate splines approximating volume data

: Kalbe, Thomas; Zeilfelder, Frank


Drettakis, G. ; European Association for Computer Graphics -EUROGRAPHICS-:
Eurographics 2008. Conference Proceedings : 29th annual conference of the European Association for Computer Graphics will be hosted by the Foundation for Research and Technology- Hellas (FORTH), Crete, Greece from Monday, April 14th to Friday 18th
Oxford: Blackwell Publishing, 2008 (Computer Graphics Forum. Conference Issue 27.2008, Nr.2)
European Association for Computer Graphics (Eurographics Annual Conference) <29, 2008, Crete>
Conference Paper
Fraunhofer IGD ()
spline; ray casting; volume data; Graphics Processing Unit (GPU); approximation

We develop an approach for hardware-accelerated, high-quality rendering of volume data using trivariate splines. The proposed quasi-interpolating schemes are realtime reconstructions. The low total degrees provide several advantages for our GPU implementation. In particular, intersecting rays with spline isosurfaces for direct Phong illumination is performed by simple root finding algorithms (analytic and iterative), while the necessary normals result from blossoming. Since visualizations are on a fragment base, our renderer for isosurfaces includes an automatic level of detail. While we use well-known spatial data structures in the CPU part of the algorithm for hierarchical view frustum culling and memory reduction, our GPU implementations have to take the highly complex structure of the splines into account. These include an appropriate organization of the data streams, i.e. we develop an advanced encoding scheme for the spline coefficients, as well as an implicit scheme for bounding geometry retrieval. In addition, we propose an elaborated clipping procedure to be performed in the fragment shader. These features essentially reduce bus traffic, memory consumption, and data access on the GPU leading to interactive frame rates for renderings of high visual quality. Compared with pure CPU implementations and existing GPU implementations for trivariate polynomials frame rates increase by factors between 10 and 100.