Towards a High-quality Visualization of Higher-order Reynold's Glyphs for Diffusion Tensor Imaging

Recent developments in magnetic resonance imaging (MRI) have shown that displaying second-order tensor information reconstructed from diffusion-weighted MRI does not display the full structure information acquired by the scanner. Therefore, higher-order methods have been developed. Besides the visualization of derived structures such as fiber tracts or tractography (directly related to stream lines in fluid flow data sets), an extension of Reynold’s glyph for second-order tensor fields is widely used to display local information. At the same time, fourth-order data becomes increasingly important in engineering as novel models focus on the change in materials under repeated application of stresses. Due to the complex structure of the glyph, a proper discrete geometrical approximation, e.g., a tessellation using triangles or quadrilaterals, requires the generation of many such primitives and, therefore, is not suitable for interactive exploration. It has previously been shown that those glyphs defined in spherical harmonic coordinates can be rendered using hardware acceleration. We show how tensor data can be rendered efficiently using a similar algorithm and demonstrate and discuss the use of alternative high-accuracy rendering algorithms. Mario Hlawitschka and Bernd Hamann Institute for Data Analysis and Visualization (IDAV), Department of Computer Science, University of California, Davis, CA, e-mail: {hlawitschka | bhamann}@ucdavis.edu Younis Hijazi Frauenhofer ITWM and University of Kaiserslautern, Germany e-mail: [email protected] Aaron Knoll University of Kaiserslautern, Germany e-mail: [email protected]