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| Study on coded excitation in color flow mapping system |
| LI Peng1, CHEN Yu-quan1, HU Da-ke2, ZHENG Yin-fei2 |
| 1. Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027, China;
2. Department of Instrument Science and Technologies, Zhejiang University, Hangzhou 310027, China |
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Abstract To circumvent the problem that the conventional color flow map（CFM） imaging’s frame rate is seriously decreased, a new method using coded excitation to get the flow velocity estimate was proposed. The method uses a broad band coded signal as excitation instead of a narrow band pulse. The received broad band signal is divided into a number of narrow band signals by filtering with a number of band filters. As these band filters have different center frequencies, the filtered signals can be seen as a number of narrow band signals which are separated in time domain. In order to improve the vertical resolution, the narrow band signals must be pulsecompressed by matched filters. Then an improved autocorrelation approach is applied on the several narrow band signals to obtain the flow velocity estimate. Finally,all the velocity estimates from each narrow band are averaged to obtain an improved velocity estimate. The result shows that, as each excitation leads to an estimated value of the velocity, this new method substantially increases the frame rate of CFM imaging.
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Published: 16 July 2010
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彩色血流成像中编码激励的研究
为了解决传统彩色血流成像(CFM)帧频降低的问题,提出一种利用编码激励一次性获取血流速度估计的方法.用宽带的编码信号替代传统的窄带信号作为激励,将得到的宽带回波信号通过若干组带通滤波器进行滤波,由于该若干组带通滤波器的中心频率不同,滤波后信号可看作是一系列时间上分离的窄带信号.为提高纵向分辨率,将这些窄带信号通过匹配滤波器进行脉冲压缩.脉冲压缩后的信号可通过改进的自相关算法计算血流速度估计值,将多次估计值求平均,得到最终的血流速度估计.由于每个扫查角度只需要发射一次,该方法能够大幅提高彩色血流成像的帧频.
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| ［1］ KASAI C, NAMEKAWA K, KOYANO A. Realtime twodimensional blood flow imaging using an autocorrelation technique ［J］. IEEE transactions on Sonics and Ultrasonics, 1985, 32(3): 458463.
［2］ BONNEFOUS O, PESQUE P. Time domain formulation of pulseDoppler ultrasound and blood velocity estimation by cross correlation ［J］. Ultrasonic Imaging, 1986 8(2): 7385.
［3］ 冯若,姚锦钟,关立勋,等.超声手册［M］.南京：南京大学出版社,1999.
［4］ MISARIDIS T, JENSEN J A. Use of modulated excitation signals in medical ultrasound. Part I: Basic concepts and expected benefits ［J］. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2005, 52(2): 177191.
［5］ GRAN F, JENSEN J A. Designing waveforms for temporal encoding using a frequency sampling method ［J］. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2007, 54(10): 20702081
［6］ UDESEN J, GRAN F, NIELSEN M B, et al. A Frequency Splitting Method for CFM Imaging ［C］∥
Proceedings of the IEEE Ultrasonics Symposium. Canada: IEEE,2006: 20192023
［7］ LI P, EBBINI E, O’DONNELL M. A new filter design technique for coded excitation systems ［J］. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 1992, 39(6): 693699.
［8］ JENSEN J A. Field: a program for simulating ultrasound systems ［J］. Medical Biological Engineering and Computing, 1996, 34(1): 351353. |
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