1. A method for processing tomographic image data, comprising: reconstructing an initial volume from a set of axial scan data, wherein the initial volume comprises incomplete frequency data; generating a modified volume from the initial volume by applying a non-linear transformation, wherein the non-linear transformation introduces frequencies missing from the initial volume; generating an artifact mask, wherein the artifact mask identifies artifact regions impacted by the frequencies missing from or corrupted in the initial volume; combining the initial volume and the modified volume using a shift variant filtration process to produce a composite volume, wherein the shift variant filtration replaces missing or corrupted frequency information in the initial volume using the corresponding estimated frequency information available in the modified volume; and blending the composite volume with the initial volume based on the artifact mask to generate a corrected volume.