Geometry-free X-ray reconstruction using the theory of convex projections

The authors apply the method of projections onto convex sets (POCS) to reconstruct an image in computer tomography. Although POCS has been used before to recover missing portions of the data set, this is the first time that it is directly used to invert raysum data. Since POCS is geometry-free, it can be directly applied to cases of incomplete data. The strength of POCS compared to other geometry-free methods is its systematic use of a priori information in a natural and consistent way along with the raysum data