1. A method for refining image data from measured projection data acquired from a computed tomographic scanner comprising: receiving the measured projection data from the computed tomographic scanner; reconstructing the measured projection data to generate initial reconstructed image data; partitioning the initial reconstructed image data into a plurality of regions based on image data quality, to generate partitioned reconstructed image data, wherein the plurality of regions comprise a good image data quality volume and a poor image data quality volume; and refining the image data quality of the partitioned reconstructed image data to generate an improved reconstructed image data.