Signal Prossing And Implementation Of Doppler In Medical Ultrasound Imaging System

As a physiological data that can not be ignored in the human body,hemodynamic information plays an important role in physical health detection,clinical diagnosis and surgical treatment.Compared with other blood flow imaging,ultrasound Doppler blood flow imaging has good real-time performance,no harm to the human body,and it can accurately measure blood flow information.Therefore,it is important to study the ultrasound Doppler mode to improve the processing accuracy and imaging level of the Doppler mode.This paper mainly studies the signal processing and implementation of Doppler in medical ultrasound imaging.The specific work is as follows:First,an ultrasound Doppler front end was designed based on FPGA.On the one hand,the quadrature demodulation algorithm is implemented,and the DDS method based on CORDIC algorithm is used to reduce the phase truncation error.The timing of the FIR filter module is optimized by pipeline method,and its performance is improved.On the other hand,a system architecture of Doppler mode is designed,which can realize B mode,CDFI mode and PW mode while ensuring image frame rate.Secondly,in the color Doppler algorithm,wall filtering algorithm,autocorrelation algorithm,priority coding and post-processing are studied.In the aspect of wall filter algorithm,the projection-initiated IIR filter and polynomial regression filter are studied.The actual human Doppler data is processed using the color Doppler algorithm,and the processing results of each process in the color Doppler algorithm are shown.In the pulse wave Doppler algorithm,the spectrum analysis algorithm and the wall filter are studied.After the wall filter processing,the spectrum analysis algorithm can successfully extract the power spectrum of the blood flow.The dynamic power spectrum of the pulse Doppler mode is obtained for the actual human Doppler data processing,and the display level of the dynamic power spectrum is optimized by the image processing algorithm.Finally,the clutter filtering algorithm based on Hankel matrix is studied.By constructing a blood flow signal model under different conditions and performing simulation.In addition,an actual blood flow imaging experiment was performed.Comparing the processing effects of various filtering algor ithms,the results show that the Hankel matrix based clutter filtering algorithm has better measurement accuracy and blood flow-tissue energy ratio than the traditional filtering algorithm,and the B-Hankel clutter filtering algorithm is compared with Hankel-The SVD clutter filtering algorithm has better performance.