北京生物醫(yī)學(xué)工程

一種新型自適應(yīng)動態(tài)濾波器在超聲成像中的應(yīng)用

Application of a new self-adaptive dynamic filter in ultrasound imaging system

作者：王文芳周盛王曉春王立偉王延群

單位：中國醫(yī)學(xué)科學(xué)院生物醫(yī)學(xué)工程研究所(天津 300192）

關(guān)鍵詞：超聲成像；可編程門陣列；快速傅里葉變換；動態(tài)濾波；濾波器；自適應(yīng)

分類號：

出版年·卷·期（頁碼）：2012·31·1（26-30）

摘要：

目的為使動態(tài)濾波器的中心頻率可實時匹配回波信號中心頻率，本文設(shè)計了一種新型的自適應(yīng)動態(tài)濾波器。方法本文自適應(yīng)機制是以快速傅里葉變換（fast Fourier transform，F(xiàn)FT）算法實時分析真實回波信號的頻率特性，根據(jù)頻率編號自適應(yīng)匹配動態(tài)濾波器的系數(shù)。該濾波器的所有模塊基于現(xiàn)場可編程門陣列(field programmable gate array，F(xiàn)PGA)硬件實現(xiàn)，最后將加入白噪聲的正弦信號使用Modelsim時序仿真工具進行仿真。結(jié)果仿真結(jié)果表明，這種濾波器能良好匹配回波信號中心頻率，消除噪聲。結(jié)論本文提出的自適應(yīng)動態(tài)濾波器滿足高速實時系統(tǒng)的要求，為超聲系統(tǒng)中濾波器的設(shè)計提供了可靠依據(jù)。

Objective A new self-adaptive dynamic filter in ultrasound imaging system was proposed to match the center frequency of the dynamic filter and the real echo in real time. Methods The fast Fourier transform(FFT)processor was used to analyze each small section of the echo and the frequency characteristic of the real echo deciding the factors of the filter in the self-adaptive mechanism. The realization of the system based on field programmable gate array(FPGA)was analyzed and the design was carried on by Modelsim as the timing simulation tool dealing with sinusoidal signals doped with white noise. Results The simulation results showed that the self-adaptive dynamic filter could reduce the noise strongly as the method could match the center frequency of the near field and far field real echo precisely. Conclusions The new self-adaptive dynamic filter is fast enough for processing high-speed and real-time signals，providing one basis for designing the filter in ultrasongraphy.

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