Research of Rendering Anisotropic Volume Data Directly Based on the Shear-Warp Algorithm

The traditional shear-warp rendering algorithm is based on isotropic volume data, which is often generated from anisotropic data by inter-slice interpolation. This paper presents a new method that renders the anisotropic volume data directly based on the shear-warp algorithm, in the condition of that there is no big difference between the slice spacing and the pixel spacing within the slice. In this new method, the coordinates are transformed from model to world according to the real sampling spacing of the original data. Finally, the constructed anisotropic volume data in the world coordinate system has the same proportion of size with the real object. The view matrix is described as the coordinate transformation matrix from world, not model, to view. Using this new method to render the anisotropic volume data directly, will not only make the volume data for rendering accurate and decrease the preprocessing time, but also meet both the requirements of image quality and rendering speed by adjusting the resampling rate during the rendering process.