【摘要】 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.更多还原

【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 pulse-compressed 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.更多还原