"Art" in X-ray tomography: Image noise reduction

Reduction of the object dose by reducing X-ray exposure has the inevitable consequence of increasing statistical noise in the projections. A set of projections with a 10% noise, collected during the test experiment at the Institute of Crystallography RAS, were used to reconstruct a water phantom. Two different reconstruction approaches (Algebraic Reconstruction Technique (ART) and Filtered Back Projections (FBP)) were implemented. The reconstructed images also had about 10 % noise in both cases. Median filtering within each ART iterative step and averaging over images, updated and preserved during the final iteration made it possible to lower the image noise to 3%. For ART calculations, the RegART software package developed by the authors was used