Ring artifact correction for industrial CT images

Ring artifacts in computed tomography (CT) images are introduced by imperfect pixel channel in a detector. Ring artifacts degrade the CT image, hamper post processing and prohibit quantitative analysis. A set of algorithms that enable virtually complete ring artifact correction were proposed. Correction for pixel channel response nonuniformity was that offset and gain correction were done to compensate for response non-uniformity in the detector. Correction for projection sinogram data was that the vertical line artifacts in the sonogram were removed by a computationally efficient filter. Correction for already-reconstructed images was that the ring artifacts in the Cartesian coordinate were transformed into the vertical line artifacts in the polar coordinate and removed as sonogram correction. The procedures were created to deal with data acquired from an YXLON XRS232 9″ image intensifies Ring artifacts were reduced significantly with minimal to negligible contamination of the underlying data.