Interactive segmentation and boundary surface formation for 3-D digital images

Abstract In visualizing objects in 3-D digital images based on shaded-surface displays, segmentation of the 3-D regions is a basic processing operation. When object and nonobject regions touch or overlap and have identical features, automatic segmentation methods fail. We present an interactive technique which permits isolation of arbitrary subregions of the 3-D image by a region filling procedure. We illustrate the usefulness of this capability, through computerized tomography data, in preoperative surgical planning and for producing arbitrary fragmentations of objects in 3-D images. The techniques are applicable in other fields as well, where independent display of overlapping structures is important. When the object regions are specified through a set of contours in a sequence of slices, we show that the boundary surfaces of the object are produceable in an efficient way using the cuberille-based discrete representation of the object surfaces. The algorithms we present for forming boundary surfaces do not impose restrictions on the shape and pattern of distribution of contours in the slices as do the surface tiling schemes reported in the literature. We assume that a contour is made up of at least three points.