A multilevel domain decomposition algorithm for fast O(N/sup 2/logN) reprojection of tomographic images

A novel algorithm for fast computation of tomographic image projections is presented. The method comprises a decomposition of an image into sub-images followed by an aggregation of projections computed for the sub-images. The multilevel domain decomposition algorithm is formulated as a recursive procedure. The computational cost of the proposed algorithm is comparable to that of FFT-based techniques but it provides better accuracy and more flexibility.