Volume images made up of "stacks" of parallel computed tomographic (CT) cross-sectional images are displayed in three dimensions utilizing the method of projection imaging. This technique involves the mathematical projection of the volume picture elements (voxels) of the 3-D image onto a plane to form a two-dimensional projection image which, for x-ray CT volume images, resemble conventional radiographs. Projection images formed at two angles of view, 2° to 8° apart, are utilized as stereo-pair projections to view the volume image in three dimensions. Before projection, selected regions of the volume image are partially dissolved or totally removed from the volume to enhance the visibility of remaining struc-tures. These processes, referred to as numerical tissue "dissolution" and "dissection", are utilized to overcome the undesired effects of superposition which occur as natural consequence of displaying a stack of cross sections as a volume image, i.e., deeper image regions are obscured by overlying structure. Examples are shown where overlying regions of the volume image have been "cut" from the volume to more clearly visualize deeper anatomy. Particular emphasis is given to the use of these methods in identifying two-and three-dimensional subregions of interest within the volume for further detailed view-ing and quantitative analysis. As an example, the use of the 3-D display of volume images to guide the process of identifying the optimal orientation of oblique section images through internal organs of the body is illustrated.

Date Published: 29 October 1981
PDF: 5 pages
Proc. SPIE 0283, Three-Dimensional Machine Perception, (29 October 1981); doi: 10.1117/12.931997

Published in SPIE Proceedings Vol. 0283:
Three-Dimensional Machine Perception
Bruce R. Altschuler, Editor(s)