Volume Rendering

A typical 3D data set is a group of 2D slice images acquired by a CT, MRI, or MicroCT scanner. Usually these are acquired in a regular pattern (e.g., one slice every millimeter) and usually have a regular number of image pixels in a regular pattern. These are examples of regular volumetric grids, with each volume element, or voxel represented by a single value that is obtained by sampling the immediate area surrounding the voxel.

A volume may be viewed by extracting surfaces of equal values from the volume and rendering them as polygonal meshes or by rendering the volume directly as a block of data. Direct volume rendering is a computationally intensive task that is performed in several ways.