Surface normal for 3D object display in cuberille environment

The authors present a surface normal estimate which is based on 3-D moments of gray-value distribution and works in either a gray-scaled or binary voxel-based scene. In the cuberille (voxel-based representation) environment, the voxel value is merely an average of some physical parameter throughout the cubic volume, so the surface extracted (explicitly or implicitly) from a such scene is no longer an exact representation of the actual object surface. An estimate of surface normal from the extracted surface might accumulate errors in object rendering by shading techniques. The proposed operator works directly on the original scene and gives for each surface point in the scene a quantity that measures the probability that a direction could be the normal vector to the surface at this point. Hence, it is able to preserve the structural details of objects. The operator provides superior realism of rendering even though a simple shading model is used.<>