| Popis: |
This paper introduces a new multislice helical weighting method. When used in conjunction with rebining from fan-beam to parallel projections, this approach leads to a single- filtering algorithm, that is, each projection needs to be filtered only once independently of the number of image reconstructions performed. This is particularly useful when overlapping images are reconstructed to fully leverage the z- resolution available from the projection data, or when performing CT fluoroscopy, where up to twelve or more images are reconstructed per 360-degree source rotation. A variable helical contribution width method is presented, which allows helical reconstruction for any selected pitch. The algorithm differs significantly from the current published helical weighting methods. In particular it can be applied at any helical pitch in a relevant continuum and to a system with any number of rows (in as much as cone-angles may be ignored). The interpolation method is chosen in such a way that the number of projections contributing to an image is adjustable. This results in user-selectable image thickness as well as user- selectable pitch. Further the minimum number of projections to be used is significantly smaller than that used with the current algorithms. |
