CAJ | 학술논문

目的：平板CT成像常产生环形伪影，其原因在于平板探测器单元因多种不利因素的影响，性能存在不一致现象，表现为投影数据内含有直线结构信息。为了实现平板CT优质成像，本文提出一种基于投影域小波滤波处理的环形伪影去除方法。方法新方法首先把线积分投影数据等间隔分成四个子投影数据，接着分别对四个子投影数据进行小波分解，生成小波系数矩阵，然后分别对小波系数进行滤波处理，新的小波系数矩阵进行小波重构生成四个新的子投影数据，并合成为新的线积分投影数据，最后再用加权均值滤波对新的线积分投影数据进行滤波处理，处理后的线积分投影数据采用滤波反投影方法进行图像重建。结果实验证明测试算法有效可行。结论实验结果表明，该方法能有效地去除环形伪影，使图像细节清晰可见。
목적：평판CT성상상산생배형위영，기원인재우평판탐측기단원인다충불리인소적영향，성능존재불일치현상，표현위투영수거내함유직선결구신식。위료실현평판CT우질성상，본문제출일충기우투영역소파려파처리적배형위영거제방법。방법신방법수선파선적분투영수거등간격분성사개자투영수거，접착분별대사개자투영수거진행소파분해，생성소파계수구진，연후분별대소파계수진행려파처리，신적소파계수구진진행소파중구생성사개신적자투영수거，병합성위신적선적분투영수거，최후재용가권균치려파대신적선적분투영수거진행려파처리，처리후적선적분투영수거채용려파반투영방법진행도상중건。결과실험증명측시산법유효가행。결론실험결과표명，해방법능유효지거제배형위영，사도상세절청석가견。
Objective Ring artifacts often appear in flat-panel detector-based CT images due to the malfunction or mis-calibration of the detector elements that result in stripe artifacts in the line integral projection (sinogram) data. The ring artifacts lower the image quality and affect image-based diagnoses. Here we propose a ring artifacts removal approach based on wavelet filtering in the sinogram domain. The line integral projection (sinogram) dataset were divided into 4 sub-sinogram dataset, and for each of them the wavelet decomposition operation was employed to produce the associated wavelet dataset, followed by filtering operation on the vertical detail band and the low-pass detail band. Wavelet reconstruction operation was then performed, and the weighted moving average filter was used to yield the filtered sinogram, which was processed using filtered back-projection (FBP) for image reconstruction. The results showed that the proposed approach could effectively remove the ring artifacts while preserving the structural information of the image.