Pincushion distortion correction for image intensifier-based volume CT

This paper reports the preliminary results from our prototype-system study for an image intensifier-based volume CT imager. The results indicate that because of pincushion distortion due to the curved input surface of an image intensifier, the spatial resolution of the system is not uniform, and the system suffers from severe resolution loss at the periphery of the image intensifier. To achieve uniform spatial resolution and improve the image quality of the three-dimensional (3D) reconstruction, the pincushion distortion needs to be correct. The authors have developed two methods to correct pincushion distortion. One method involves transforming the projection data with the curved detector into data with a flat detection plane prior to a direct 3D reconstruction by using an existing 3D reconstruction that assumes a flat detector. The other method is to use a newly derived algorithm (described in another paper) that assumes a curve detector for a direct 3D reconstruction