High quality rendering of attributed volume data

Abstract

For high quality rendering of objects segmented from tomographic volume data the precise location of the boundaries of adjacent objects in subvoxel resolution is required. We describe a new method that determines the membership of a given sample point to an object by reclassifying the sample point using interpolation of the original intensity values and searching for the best fitting object in the neighbourhood. Using a ray-casting approach we then compute the surface location between successive sample points along the viewingray by interpolation or bisection. The accurate calculation of the object boundary enables a much more precise computation of the gray-level-gradient yielding the surface normal. Our new approach significantly improves the quality of reconstructed and shaded surfaces and reduces aliasing artifacts for animations and magnified views. We illustrate the results on different cases including the Visible-Human-Data, where we achieve nearly photo-realistic images. CR Categories: I.3.3 [Computer Graphics]: Picture/Image Generation---Display algorithms; I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism---Color, shading, shadowing and texture Keywords: partial-volume-effect, ray-casting, tomographic data, Visible-Human-Project 1