In visualizing objects in 3-D digital images based on shaded-surface displays, segmen-tation of the 3-D regions corresponding to the objects to be visualized is a basic processing operation. When object and non-object regions touch or overlap and have similar features, automatic segmentation methods fail. To overcome this problem, a method, based on creating an arbitrarily-shaped three-dimensional window that encloses only the object regions, is proposed in this paper. The window is created using the contours traced in a series of 'slices' comprising the 3-D image. The capability to create arbitrarily-shaped 3-D windows also permits 3-D visualization corresponding to arbitrary intersections of the object. Having identified the object regions in the 3-D image, the next important processing operation before the 3-D display of an object can be achieved is the formation of its boundary surfaces. A simple and fast algorithm to form boundary surfaces from a given set of contours is presented in this paper which makes use of the 'cuberille model' for the representation of discrete surfaces. The performance of the algorithms is illustrated using computerized tomography data.
Jayaram K. Udupa,
"Segmentation And Boundary Surface Formation For 3-D Digital Images", Proc. SPIE 0271, Advances in Display Technology II, (28 July 1981); doi: 10.1117/12.931771; https://doi.org/10.1117/12.931771