Rapid Three Dimensional Display Of Medical Data Using Ordered Surface List Representations
C. Gibson · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1989
A convenient form of 3-D object representation for medical data is the voxel approach. Both simple and complex objects can be represented easily, but large numbers of voxels are required to describe smooth shapes. Considerable data compression can be achieved by representing only surface voxels. Enumeration of these in an ordered back-to-front sequence generates a list of surface voxels which incorporates shape information. Simple traversal of this ordered surface list corresponds to a full back-to-front traversal of the surface elements of the original object, which essentially solves the hidden surface problem. For cubic voxels only eight ordered surface lists are required to generate hidden surface images from any angle. This approach has been applied to radionuclide tomograms sampled at 643 resolution, achieving real time display using a conventional medical imaging computer. The technique has also been applied to CT and MRI data sampled at higher resolution. Segmentation and traversal of an N3 array of voxels to obtain surface lists is an 0(N3) procedure. However, list length is proportional to object surface area, and hence subsequent display is only an 0(N2) procedure. This property enables interactive display of large arrays without using special purpose hardware.