Generalized image synthesis from projections

A reconstruction technique is reconsidered and a radio application is described for imaging a confined region using projections or ring scans around concentric arcs centered at the image field periphery. The point-spread function varies across the image, in common with other forms of reconstruction in radioastronomy, computerized tomography, and elsewhere. The more common reconstruction from parallel projections is seen as a limiting case of either ring scan synthesis or fan beam synthesis. These various projections are combined in a general view of image synthesis based on polar coordinate descriptions of a circular imaging region.