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Ultrasonic Imaging at Low Rate Based on FRI

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Tutor: HuangDaoPing
School: South China University of Technology
Course: Detection Technology and Automation
Keywords: Sub-Nyquist Sampling,Ultrasonic imaging at low rate,Multichannel Samplingof Mixi
CLC: TN911.7
Type: Master's thesis
Year:  2013
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The recently proposed CS theory suggests that sparse signal which is sampled belowNyquist frequency can also be exactly reconstructed. The method of sampling below theNyquist frequency is referred to as Sub-Nyquist sampling method. Applying this method toUltrasound imaging can effectively reduce data size and sampling frequency, which meanssmaller machine size and less power loss. This method of ultrasound imaging is referred to asultrasound imaging at low rate. However, there exists no proper sub-Nyquist sampling methodthat can be directly applied to ultrasound imaging at low rate. Because existing sub-Nyquistsampling methods have many problems, some are unstable, some have strict restrictions,some have other problems. In this paper, on the basis of previous research, combining FRItheory with phased array ultrasound imaging features, we propose a sub-Nyquist samplingmethod that can be applied to ultrasound imaging, which is referred to as multichannelsampling of mixing Fourier series coefficients.The process of multichannel sampling of mixing Fourier series coefficients is as follows:First of all, in each channel, the original signal is multiplied with the carrier wave, to producea new analog signal. Then, we sample the integration of the new analog signal, to obtain a setof linear combination of the Fourier coefficients of the original signal. Again, we get theFourier coefficients by linear transformation. Finally, we reconstruct the signal used spectrumanalysis theory.Multichannel sampling of mixing Fourier series coefficients is not only applicable toultrasound imaging of A-type, B-type ultrasonic imaging can also be used after subsequentdeformation. In Chapter4, we combine the mathematical characteristics of B-type ultrasonicimaging with multichannel sampling of mixing Fourier series coefficients, to obtain acomplete set of B-type ultrasonic imaging at low rate.At the end of the article, the solutions of several problems encountered in the practicalapplication for multichannel sampling of mixing Fourier series coefficients.
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