| Popis: |
The sampling geometry for conventional, multidetector, computed tomography is illustrated in terms of the Radon transformation for both rotate-rotate (3rd generation fan beam) and rotate-stationary (4th generation fan beam) scanners. By deriving an expression for the outline of the sampling region in the Radon transformation for each detector measurement it is demonstrated that the entire Radon transformation can be covered by non-overlapping sampling regions with the assumption of negligible detector dead space. An expression for angular aliasing is derived which demonstrates that object dependent artifacts can occur if the angular width of the sampling regions in conjunction with the angular sampling increment does not provide sufficient suppression of the high order angular harmonics in the representation of the scanned object. The number of views necessary to suppress angular aliasing, as well as the potential spatial resolution and general image quality are shown to be fundamentally related to the size, shape, and relative orientation of the Radon transformation sampling regions.© (1981) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
