-
摘要: 有效去除CT图像中环形伪影是医学图像处理领域的一个重要研究方向,现有的方法在去除环形伪影的同时,对CT图像的边缘及细节保留存在困难和挑战.本文采用变分优化的思想,将环形伪影的去除问题建模为一个能量最小化问题,来缓解保持图像信息和去除伪影之间的矛盾,提出了一种后处理的伪影校正算法.根据环形伪影产生机理和特性表现构造有针对性的变分模型,一是从环形伪影的几何特性入手,设计更为合理的梯度保真形式,增强模型对图像细节信息的保护;二是从环形伪影的边缘特性入手,构建具有伪影辨识能力的相对全变分正则项,降低模型对图像结构性信息的影响.基于构造的变分模型,采用高效的优化求解算法,实现环形伪影的有效去除.对比实验表明,无论在视觉观察还是定量分析方面,本文算法均体现出了较好的性能.Abstract: Effective removal of ring artifacts in CT images is an important research area in the field of medical image processing. The existing methods have some difficulties and challenges in preserving the edges and details of CT images while removing ring artifacts. In this paper, we model the removal of ring artifacts as a problem of energy minimization based on the idea of variational optimization and propose a post-processing method to alleviate the conflict between maintaining image information and removing artifacts. The variational model has been constructed according to the analysis of the mechanism and characteristics of ring artifacts. On the one hand, we design a more suitable gradient fidelity term based on the geometrical characteristics of ring artifacts to enhance the protection on image details. On the other hand, we construct a relative total variational regular term with the ability of artifact identification based on the edge characteristics of ring artifacts, so as to reduce influences on the structural information of images. The designed variational model is to be solved by an efficient optimization algorithm to effectively remove ring artifacts. Experimental results show that the proposed method presents better performance on both visual inspection and quantitative assessment.
-
Key words:
- CT image /
- ring artifact /
- post-processing /
- variational model
1) 本文责任编委 张道强 -
表 1 各算法结果的图像质量评价指标值
Table 1 Quantitative comparison for the different methods
算法 Shepp-Logan图像 Lena图像 PSNR MSSIM PSNR MSSIM WF算法 36.4504 0.8841 36.0376 0.9897 RCP算法 42.5464 0.8925 36.0161 0.9888 VDM算法 43.7735 0.9010 37.0608 0.9945 本文算法 49.0341 0.9679 37.9287 0.9966 -
[1] Szyszko T A, Gjr C. PET/CT and PET/MRI in head and neck malignancy. Clinical Radiology, 2018, 73(1):60-69 https://www.ncbi.nlm.nih.gov/pubmed/29029767 [2] 韩光辉, 刘峡壁, 郑光远.肺部CT图像病变区域检测方法.自动化学报, 2017, 43(12):2071-2090 http://www.aas.net.cn/CN/abstract/abstract19182.shtmlHan Guang-Hui, Liu Xia-Bi, Zheng Guang-Yuan. Automated detection of lesion regions in lung computed tomography images:a review. Acta Automatica Sinica, 2017, 43(12):2071-2090 http://www.aas.net.cn/CN/abstract/abstract19182.shtml [3] 江孝国, 张开志, 李成刚, 王远.图像平场校正方法的扩展应用研究.光子学报, 2007, 36(9):1587-1590 http://d.old.wanfangdata.com.cn/Periodical/gzxb200709006Jiang Xiao-Guo, Zhang Kai-Zhi, Li Cheng-Gang, Wang Yuan. Extended applications of image flat-field correction method. Acta Photonica Sinica, 2007, 36(9):1587-1590 http://d.old.wanfangdata.com.cn/Periodical/gzxb200709006 [4] 傅健, 路宏年.扇束X射线ICT中环状伪影的一种校正方法.光学精密工程, 2002, 10(6):542-546 doi: 10.3321/j.issn:1004-924X.2002.06.002Fu Jian, Lu Hong-Nian. Correcting method for ring artifacts in fan-beam X-ray ICT. Optics and Precision Engineering, 2002, 10(6):542-546 doi: 10.3321/j.issn:1004-924X.2002.06.002 [5] Raven C. Numerical removal of ring artifacts in microtomography. Review of scientific instruments, 1998, 69(8):2978-2980 doi: 10.1063/1.1149043 [6] Münch B, Trtik P, Marone F, et al. Stripe and ring artifact removal with combined wavelet-Fourier filtering. Optics Express, 2009, 17(10):8567-8591 doi: 10.1364/OE.17.008567 [7] Ashrafuzzaman A N M, Lee S Y, Hasan M K. A self-adaptive approach for the detection and correction of stripes in the sinogram:suppression of ring artifacts in CT imaging. EURASIP Journal on Advances in Signal Processing, 2011, 2011(1):1-13 http://d.old.wanfangdata.com.cn/OAPaper/oai_doaj-articles_a074aeaf4d859728152788be8a7939c6 [8] Hasan M K, Sadi F, Lee S Y. Removal of ring artifacts in micro-CT imaging using iterative morphological filters. Signal, Image and Video Processing, 2012, 6(1):41-53 doi: 10.1007/s11760-010-0170-z [9] Anas E M, Lee S Y, Hasan K. Classification of ring artifacts for their effective removal using type adaptive correction schemes. Computers in Biology and Medicine, 2011, 41(6):390-401 doi: 10.1016/j.compbiomed.2011.03.018 [10] Rashid S, Lee S Y, Hasan M K. An improved method for the removal of ring artifacts in high resolution CT imaging. EURASIP Journal on Advances in Signal Processing, 2012, 2012(1):93 doi: 10.1186/1687-6180-2012-93 [11] Kim Y, Baek J, Hwang D. Ring artifact correction using detector line-ratios in computed tomography. Optics express, 2014, 22(11):13380-13392 doi: 10.1364/OE.22.013380 [12] Miqueles E X, Rinkel J, O'Dowd F, et al. Generalized Titarenko's algorithm for ring artefacts reduction. Journal of Synchrotron Radiation, 2014, 21(6):1333-1346 doi: 10.1107/S1600577514016919 [13] Titarenko V. Analytical formula for two-dimensional ring artefact suppression. Journal of Synchrotron Radiation, 2016, 23(6):1447-1461 doi: 10.1107/S160057751601479X [14] Paleo P, Mirone A. Ring artifacts correction in compressed sensing tomographic reconstruction. Journal of Synchrotron Radiation, 2015, 22(5):1268-1278 doi: 10.1107/S1600577515010176 [15] Sijbers J, Postnov A. Reduction of ring artefacts in high resolution. Physics in Medicine and Biology, 2004, 49(14):N247 doi: 10.1088/0031-9155/49/14/N06 [16] Prell D, Kyriakou Y, Kalender W A. Comparison of ring artifact correction methods for flat-detector CT. Physics in medicine and biology, 2009, 54(12):3881-3895 doi: 10.1088/0031-9155/54/12/018 [17] Wei Z, Wiebe S, Chapman D. Ring artifacts removal from synchrotron CT image slices. Journal of Instrumentation, 2013, 8(06):C06006 doi: 10.1088/1748-0221/8/06/C06006 [18] Yan L, Wu T, Zhong S, Zhang Q. A variation-based ring artifact correction method with sparse constraint for flat-detector CT. Physics in medicine and biology, 2016, 61(3):1278-1292 doi: 10.1088/0031-9155/61/3/1278 [19] Huo Q, Li J, Lu Y, Yan Z. Removing ring artifacts in CBCT images using smoothing based on relative total variation. In:Proceedings of the 2016 International Conference on Neural Information Processing. Kyoto, Japan:Springer, Cham, 2016. 501-509 [20] Huo Q, Li J, Lu Y, Yan Z. Removing ring artifacts in CBCT images via L0 smoothing. International Journal of Imaging Systems and Technology, 2016, 26(4):284-294 doi: 10.1002/ima.22200 [21] Liang X, Zhang Z, Niu T, Yu S, Wu S, Li Z, et al. Iterative image-domain ring artifact removal in cone-beam CT. Physics in Medicine and Biology, 2017, 62(13):5276-5292 doi: 10.1088/1361-6560/aa7017 [22] Tang S, Gong W, Li W, Wang W. Non-blind image deblurring method by local and nonlocal total variation models. Signal Processing, 2014, 94(1):339-349 http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=39e15af175cb22de05ca634f1611d3e6 [23] 李权合, 毕笃彦, 许悦雷, 查宇飞.雾霾天气下可见光图像场景再现.自动化学报, 2014, 40(4):744-750 http://www.aas.net.cn/CN/abstract/abstract18340.shtmlLi Quan-He, Bi Du-Yan, Xu Yue-Lei, Zha Yu-Fei. Haze degraded image scene rendition. Acta Automatica Sinica, 2014, 40(4):744-750 http://www.aas.net.cn/CN/abstract/abstract18340.shtml [24] Kim Y, Vese L A. Image recovery using functions of bounded variation and Sobolev spaces of negative differentiability. Inverse Problems and Imaging, 2017, 3(1):43-68 http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=662bb3848cc767c2bb159a4e62148848 [25] 张桂梅, 孙晓旭, 刘建新, 等.基于分数阶微分的TV-L1光流模型的图像配准方法研究.自动化学报, 2017, 43(12):2213-2224 http://www.aas.net.cn/CN/abstract/abstract19194.shtmlZhang Gui-Mei, Sun Xiao-Xu, Liu Jian-Xin, et al. Research on TV-L1 optical flow model for image registration based on fractional-order differentiation. Acta Automatica Sinica, 2017, 43(12):2213-2224 http://www.aas.net.cn/CN/abstract/abstract19194.shtml [26] Rudin L I, Osher S, Fatemi E. Nonlinear total variation based noise removal algorithms. Physica D Nonlinear Phenomena, 1992, 60(1-4):259-268 doi: 10.1016/0167-2789(92)90242-F [27] Bouali M, Ladjal S. Toward optimal destriping of MODIS data using a unidirectional variational model. IEEE Transactions on geoscience and remote sensing, 2011, 49(8):2924-2935 doi: 10.1109/TGRS.2011.2119399 [28] Zhang H, He W, Zhang L, Shen H, Yuan Q. Hyperspectral image restoration using low-rank matrix recovery. IEEE Transactions on Geoscience and Remote Sensing, 2014, 52(8):4729-4743 doi: 10.1109/TGRS.2013.2284280 [29] Chang Y, Yan L, Fang H, Luo C. Anisotropic spectral-spatial total variation model for multispectral remote sensing image destriping. IEEE Transactions on Image Processing, 2015, 24(6):1852-1866 doi: 10.1109/TIP.2015.2404782 [30] Chan T F. Aspects of total variation regularized L1 function approximation. Siam Journal on Applied Mathematics, 2005, 65(5):1817-1837 doi: 10.1137/040604297 [31] Micchelli C A. Proximity algorithms for image models Ⅱ:L1/TV denoising. Advances in Computational Mathematics, 2011, 38:401-426 doi: 10.1007/s10444-011-9243-y [32] Xu L, Yan Q, Xia Y, Jia J. Structure extraction from texture via relative total variation. ACM Transactions on Graphics, 2012, 31(6):139-148 http://d.old.wanfangdata.com.cn/Periodical/dbch201901051