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Rendering

Visualization software is written using OpenGL and GLUT. DT-MRI anisotropy for the volume is shown using 2D texture mapping on the three orthogonal planes. Fibers are rendered using illuminated streamline techniques described in Banks Banks94 and Hege Hege96 with diffuse and specular terms. Stream tubes are rendered as a longs sequence of cylinder primitives with axes following the fiber. For glyph based rendering, we choose to form rotation and scaling matrices from eigenvectors and eigenvalues for every voxel of the original data and then apply them to cubes positioned in the center of those voxels. The direction of eigenvectors and magnitude of corresponding eigenvalues together with anisotropy measures are pre-computed to allow interactive frame rate during visualization. All renderings are performed using NVIDIA GeForce4 Ti4200 video card on Pentium4 2.80GHz PC with 1GB of RAM.

Leonid Zhukov 2003-09-10