Analysis of correlation coefficient filtering in elasticity imaging.
Analysis of correlation coefficient filtering in elasticity imaging.
复制标题
弹性成像中相关系数滤波分析。
DOI：
10.1109/tuffc.950
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
O'Donnell,Matthew
中科院分区：
文献类型：
--
作者：
Huang,Sheng-Wen;Rubin,JonathanM;Xie,Hua;Witte,RussellS;Jia,Congxian;Olafsson,Ragnar;O'Donnell,Matthew
相关散斑跟踪方法是弹性成像中常用的估计位移的方法。在局部应变存在的情况下，窗口尺寸越大，位移误差越大。为了减少跟踪误差，我们提出了一个短相关窗和一个相关系数滤波器。虽然仿真和实验结果证明了该方法的有效性，但相关系数滤波降低跟踪误差的原因尚不清楚，因为如果不进行滤波前的归一化处理，跟踪误差会增加。本文根据互相关函数的实部和虚部的统计特性，通过估计相关函数的相位方差和真实时滞下的相关系数来分析跟踪误差。通过识别互相关函数的幅度波动对函数虚部的影响，阐明了归一化的作用。此外，我们还给出了轴向位移误差随应变、系统参数(信噪比、中心频率、信号和噪声带宽)以及跟踪参数(窗口和滤波器大小)在滤波前归一化和未归一化情况下的函数的解析表达式。对于无噪声情况和一般情况，模拟结果与理论符合得很好，应变的经验修正项最高可达4%。
Correlation-based speckle tracking methods are commonly used in elasticity imaging to estimate displacements. In the presence of local strain, a larger window size results in larger displacement error. To reduce tracking error, we proposed a short correlation window followed by a correlation coefficient filter. Although simulation and experimental results demonstrated the efficacy of the method, it was not clear why correlation coefficient filtering reduces tracking error since tracking error increases if normalization before filtering is not applied. In this paper, we analyzed tracking errors by estimating phase variances of the cross-correlation function and the correlation coefficient at the true time lag based on statistical properties of these functions' real and imaginary parts. The role of normalization is clarified by identifying the effect of the cross-correlation function's amplitude fluctuation on the function's imaginary part. Furthermore, we present analytic forms for predicting axial displacement error as a function of strain, system parameters (signal-to-noise ratio, center frequency, and signal and noise bandwidths), and tracking parameters (window and filter sizes) for cases with and without normalization before filtering. Simulation results correspond to theory well for both noise-free cases and general cases with an empirical correction term included for strains up to 4%.
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影响因子：
4.4
作者：
I. Bailey;M. Bullimore;T. Raasch;Hugh R. Taylor
通讯作者：
I. Bailey;M. Bullimore;T. Raasch;Hugh R. Taylor
影响因子：
4.4
作者：
Park, In Ki;Chun, Yeoun Sook;Hwang, Jeong-Min
通讯作者：
Hwang, Jeong-Min
使用交叉校准的临床分级量表对球部发红进行分级。
影响因子：
4.4
作者：
Marc Schulze;N. Hutchings;T. Simpson
通讯作者：
T. Simpson
影响因子：
2.9
作者：
Efron, N;Morgan, PB;Katsara, SS
通讯作者：
Katsara, SS
DOI：
10.1148/radiographics.7.6.3423333
发表时间：
1987
期刊：
Radiographics : a review publication of the Radiological Society of North America, Inc
影响因子：
--
作者：
Pizer,SM;Johnston,RE;Rogers,DC;Beard,DV
通讯作者：
Beard,DV