Ring-artifact Correction Method for Large-size Object CT Images Based on Gradient Featured Cluster Analysis

In this paper, a Hough transform method based on image gradient featured extraction is proposed to eliminate the ring artifacts of CT scanning system. Firstly, we use the gradient featured cluster analysis of the polar coordinate image to preliminary select the reconstructed image data. Then the Hough transform is adopted to detect the lines of the recombined data. When the artifacts in the original image are mapped out, the linear artifacts in the polar coordinate image are eliminated by interpolation. Then we can purposefully eliminate the ring artifacts in the reconstructed image. Simulation and experimental results show that with the image gradient featured cluster analysis, the effective number of detected artifact lines is greatly increased, the ring artifacts, arc artifacts and cluster artifacts in the central area of the reconstructed images are effectively removed, and the erroneous detection of lines by traditional Hough transform method is greatly reduced.