Normal Estimation in 3D Discrete Spac

hree-dimensional voxel-based objects are inherently discrete and do not l f maintain any notion of a continuous surface or normal values, which are crucia or the simulation of light behavior. Thus in volume rendering, the normal s vector of the displayed surfaces must be estimated prior to rendering. We urvey several methods for normal estimation and analyze their performance. s One unique method, the context sensitive approach, employs segmentation and egment-bounded operators that are based on object and slope discontinuities in c o order to achieve high fidelity normal estimation for rendering volumetri bjects.