ISSN 1004-4140
CN 11-3017/P

基于小波变换的锥束CT滤线栅条纹去除方法

王宇昂, 高河伟, 张丽

王宇昂, 高河伟, 张丽. 基于小波变换的锥束CT滤线栅条纹去除方法[J]. CT理论与应用研究, 2023, 32(4): 437-449. DOI: 10.15953/j.ctta.2022.233.
引用本文: 王宇昂, 高河伟, 张丽. 基于小波变换的锥束CT滤线栅条纹去除方法[J]. CT理论与应用研究, 2023, 32(4): 437-449. DOI: 10.15953/j.ctta.2022.233.
WANG Y A, GAO H W, ZHANG L. Removal of Gridline Artifacts in Cone-beam CT Based on Wavelet Transform[J]. CT Theory and Applications, 2023, 32(4): 437-449. DOI: 10.15953/j.ctta.2022.233. (in Chinese).
Citation: WANG Y A, GAO H W, ZHANG L. Removal of Gridline Artifacts in Cone-beam CT Based on Wavelet Transform[J]. CT Theory and Applications, 2023, 32(4): 437-449. DOI: 10.15953/j.ctta.2022.233. (in Chinese).

基于小波变换的锥束CT滤线栅条纹去除方法

基金项目: 国家自然科学基金(融合动态能谱与个性化建模的冠状动脉容积成像方法与关键技术(62031020))。
详细信息
    作者简介:

    王宇昂: 男,清华大学工程物理系博士研究生,主要从事辐射成像研究,E-mail:wangya22@mails.tsinghua.edu.cn

    通讯作者:

    张丽: 女,清华大学工程物理系首席研究员,主要从事辐射成像研究,E-mail:zli@tsinghua.edu.cn

  • 中图分类号: O  242;TP  391

Removal of Gridline Artifacts in Cone-beam CT Based on Wavelet Transform

  • 摘要: 采用平板探测器的X射线锥束成像系统中,由于散射会带来图像伪影从而劣化图像质量,通常采用在平板探测器前安装滤线栅来去除散射,但滤线栅会在获取的图像上形成周期性的条状伪影,如何去除条状伪影是X射线锥束成像系统中的一个关键技术问题。本文对已有的滤线栅条纹去除方法进行概述,创新性地提出基于频谱拼接的小波变换方法,既能在损失物体细节信息少的前提下很好地去除滤线栅条纹,又不会引入小波变换谐波。通过实际实验,检验该方法的有效性。
    Abstract: In cone-beam computed tomography with flat-panel imagers, scattered X-ray photons lead to reduced image quality. Insertion of an anti-scatter grid between the patient or object and the flat-panel imagers is one of the most used techniques for reducing scattered radiation. However, while the scatter is reduced, gridline artifacts can be visible. Suppressing gridline artifacts in cone-beam computed tomography is significant. In this paper, the existing methods of removing gridline artifacts are summarized. Moreover, the wavelet transform method based on spectrum coalescence is innovatively proposed for removing gridline artifacts. Wavelet transform can remove gridline artifacts effectively and without introducing wavelet transform harmonics thus reducing the loss of object details. The effectiveness of this method is verified by experiments.
  • 图  1   水平放置的防散射滤线栅的主视图和俯视图

    Figure  1.   Front view and top view of the anti-scattering grid placed horizontally

    图  2   小波变换方法去除滤线栅条纹的整体思路

    Figure  2.   Schematic representation of the idea to remove gridline artifacts by wavelet transform

    图  3   第10层多贝西小波的低通和高通滤波器响应函数的幅度谱

    Figure  3.   Amplitude spectrum of low-pass and high-pass filter response functions of layer 10 Daubechies wavelet

    图  4   频谱拼接的必要性

    Figure  4.   Necessity of spectrum coalescence

    图  5   频谱拼接方法

    Figure  5.   The method of spectrum coalescence

    图  6   频谱拼接的视觉效果

    Figure  6.   Visual effect of spectrum coalescence

    图  7   实验装置

    Figure  7.   Experimental equipment

    图  8   检验小波变换方法有效性的对照实验

    Figure  8.   A comparative experiment to test the effectiveness of the wavelet transform method

    图  9   小波变换法处理前后的“水”

    Figure  9.   “Water” before and after processing by the wavelet transform method

    图  10   小波变换法处理前后的“老鼠”

    Figure  10.   “Mouse” before and after processing by the wavelet transform method

    图  11   小波变换处理后的老鼠

    Figure  11.   “Mouse” after processing by the wavelet transform method

    图  12   “水”在小波变换法处理前后的差异的一维离散傅里叶变换幅度谱

    Figure  12.   One dimensional discrete Fourier transform amplitude spectrum of the difference of “water” before and after processing by the wavelet transform method

    图  13   “水”在高斯带阻滤波或小波变换法处理前后的差异的二维离散傅里叶变换幅度谱的局部

    Figure  13.   The local region of the amplitude spectrum of two-dimensional discrete Fourier transform of the difference in “water” before and after the processing with the Gaussian band stop filter or wavelet transform method

    图  14   经对照组1、实验组1、实验组2处理后的“水”的一维离散傅里叶变换幅度谱

    Figure  14.   One dimensional discrete Fourier transform amplitude spectrum of “water” treated with control group 1, experimental group 1, and experimental group 2

    图  15   经对照组1、实验组1、实验组2处理的“水”CT重建的中心截面局部图

    Figure  15.   Local central section of “water” CT reconstruction treated with control group 1, experimental group 1 and experimental group 2

    图  16   经对照组1、实验组1、实验组2处理的“老鼠”CT重建的中心截面局部图

    Figure  16.   Local central section of “mouse” CT reconstruction treated with control group 1, experimental group 1, and experimental group 2

    表  1   频谱拼接的定量效果

    Table  1   Quantitative effect of spectrum coalescence

    统计参数加条纹图像不做频谱拼接图像做频谱拼接图像
    峰值信噪比    29.719 34.475 37.758
    结构相似性    0.9840.9950.998
    与原图差异的标准差9.1225.0853.458
    下载: 导出CSV
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出版历程
  • 收稿日期:  2022-11-22
  • 录用日期:  2023-01-06
  • 网络出版日期:  2023-01-13
  • 发布日期:  2023-07-30

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