Three-dimensional data display on the two-dimensional screen.

Abstract

The difficulties encountered when implement at ing orthographic reprojection of 3-dimensional image data onto a 2-dimensional screen are considerable. They arise principally because of the size of data being manipulated and the tendency for underlying or overlying structures to obscure a clear view of the desired image. In this work, implementation was performed with an orthographic reprojection technique and many heuristic approaches were used to resolve some of the related problems. Several coordinate rotating algorithms were tested in this work. Among them the Precalculation and Indexing method proved to be the most efficient algorithm. Due to the disparity of the viewing- coordinate grids and the voxels of the volume data after rotation, 3-dimensional interpolation is required for appling the reprojection technique. Several methods implementing linear interpolation have been tried. Interpolation with a cone-shape kernel is the most appropriate method in the 2D situations and can be easily extended to a sphere-shape kernel in 3D situations. The orthographic reprojection method includes a single plane dissection capability. Results on an artificial test data are collected using the above algorithms. Several resulting images are included as well as the associated PASCAL programs.