目的 定量超声技术是通过测量骨骼的宽带超声衰减(broadband ultrasound attenuation,BUA)等参数以反映骨骼骨矿密度的方法.然而由于骨骼对超声波的严重衰减,接收到的透射信号非常微弱且伴有强噪声,从而限制了超声的测量深度.为消除噪声影响,提高测量深度,本文提出将巴克码应用于测量松质骨BUA.方法 采用巴克码调制脉冲发射信号,利用巴克码尖锐的自相关特性对接收信号进行脉冲压缩,然后用压缩脉冲的频谱分析松质骨的BUA值.结果 通过仿真和样品实测结果发现该方法相对于传统方法具有更好的抗干扰能力,及更平稳的BUA衰减曲线,从而得到更精确的测量结果.结论 本方法既能提高松质骨BUA的测量精度,又能增大测量深度.%Objective Quantitative ultrasound ( QUS ) is a measurement method of bone mineral density ( BMD ),by measuring broadband ultrasound attenuation ( BUA ) to reflect cancellous bone BMD. However,the received signals are always very weak and accompanied by strong noise because ultrasonic wave is seriously attenuated by cancellous bone,which limits the measurement depth. In order to reduce the impact of noise to improve the measurement depth, this paper proposes a method which applies Barker code to measure BUA of cancellous bone. Methods We use Barker code to modulate the transmitting pulse signals, and compress the received signals with the sharp correlation property of Barker code. The compressed pulse spectra are used to analysis BUA of cancellous bone. Results Through simulation and sample measurement, the results show that this method has better anti-jamming capability, smoother BUA attenuation curve, which lead to more accurate measurement results compared to traditional methods. Conclusions This method can improve not only the measurement accuracy but also the measurement depth of the cancellous bone' s BUA.
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