X射线CT成像条状伪影校正

Streak Artifact Correction in X-ray CT Imaging

X射线CT成像过程中,由光子饥饿引起的CT图像中的条状伪影退化了CT图像的质量,增大了CT图像的数值统计误差,进而影响到材料探测结果。本文提出了一种基于自适应中值滤波的条状伪影校正方法,该方法依据投影数据的幅值自适应地设定滤波的窗口尺寸。针对多个相邻探元处于光子饥饿状态的情况,设定了阈值,判断中值滤波后的投影信号幅值是否处于阈值之下,否则继续扩大滤波窗口,直至满足阈值判断准则。本文通过实验验证了方法的有效性,该方法简单易行,适于实际工程应用。

During the procedure of X-ray CT imaging, the streak artifact caused by photon starvation depresses the CT image quality and increases the statistical error of numerical value in CT image, and the material detection results will be influenced. In this paper, an adaptive streak artifact correction method was put forward. According to the proposed method, the length of median filter window was determined based on the projection value. For the situation that multiple adjacent detector elements were in the case of photon starvation, a suitable threshold was set. The projection value after adaptive median filter was firstly judged. If the modified projection value is greater than the threshold, the length of median filter window increases until the judgment criteria are satisfied. Actual experimental results verify the effectiveness of the method in this paper. The proposed method is simple and easily performed, and it is suitable to engineering application.