A novel image restoration method assisted by reference image in dual-energy CT

Because of its remarkable material discrimination ability, dual-energy CT (DECT) becomes more and more important in security inspection, medical diagnosis and other industrial areas. Four images can be reconstructed in one dual-energy scan, and the effective atomic number image suffers from decomposition imprecision, system noise and the look-up table errors, so its quality is always poorer than the attenuation images. But the four images should have the same structures. In this paper, we propose a novel image restoration method that uses the attenuation image as reference image to improve the quality of the atomic number image. The structure information/weighting is obtained using the bilateral filtering method in the attenuation image and then we restore the atomic number image. Using the method, the image quality of the effective atomic number is improved prominently and the artifacts can be suppressed obviously. Two experiments were conducted to prove that the method is effective in DECT image processing.