A method of reducing ring artifacts in tomographic images including
providing an original digitized projection measurement comprising a
plurality of intensities corresponding to a domain of points on an
2-dimensional grid, operating on said original projection measurement
with a filter wherein features of high radial frequency and low angular
frequency are attenuated, forming a weighted mixture of said filtered
projection measurement and said original projection measurement wherein
ring artifacts in said original tomographic image are substantially
reduced, and reconstructing the projection measurement to form a
tomographic image. Alternatively, a first tomographic image is
reconstructed from said original projection measurement, a second
tomographic image is reconstructed from said filtered projection
measurement, and a weighted mixture is formed from said first tomographic
image and said second tomographic image.