基于投影域校正的CT图像环形伪影去除方法

摘要

为去除由于探测器中探测元连续坏死导致的CT图像中出现的环形伪影,提出一种基于投影正弦图校正的方法.利用两侧正常值对正弦图中直线区域进行线性插值,重建图像;对重建图像进行滤波,弱化伪影并保持图像锐利,得到先验图像;对先验图像进行前向投影,得到先验正弦图,用于估计原始先验正弦图中直线伪影区域信息,再次重建.实验结果表明,该方法对探测器大面积探测元坏死导致的严重环形伪影具有很好的校正效果,保持了图像的细节和空间分辨率.%A method based on projection sinogram correction was proposed to remove ring artifact of CT image in the case where some adjacent bins in detector don't work.Linear interpolation was applied to the data of dark line region in uncorrected projection sinogram using the normal data on the two sides of dark line region.Image was reconstructed from the linear-interpolation sinogram.Filtering was applied to the reconstructed image to get one prior image with less artifacts and sharp structures.This prior image was forward projected to generate a prior sinogram used to estimate the data in the dark line region from uncorrected projection sinogram.The image with no ring artifacts was reconstructed using corrected sinogram.Experimental results show that this method can produce satisfactory no-ring-artifact results in the case that some dead adjacent bins exist in the detector.At the same time, detailed structures and image resolution can be preserved well.