基础序列调制的Golay码研究长骨中的超声导波  

Study on the flexural guided waves in coated long bone with base sequence modulated Golay code

作　　者：宋小军[1] 他得安[2,3] Petro Moilanen 

机构地区：[1]上海电力学院电子科学与技术系,上海200090 [2]复旦大学电子工程系,上海200433 [3]上海市医学图像处理与计算机辅助手术重点实验室,上海200032 [4]Jyvaskyla大学物理系,芬兰40014

出　　处：《仪器仪表学报》2014年第7期1564-1570,共7页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(11174060;11327405);上海市科技支撑计划(13441901900);教育部博士点基金(20110071130004;2013007110020)资助项目

摘　　要：利用超声导波评价长骨状况已引起越来越多的关注.长骨外附软组织使得接收到的导波信噪比（SNR）很低,因此难以应用在连体测量中.引入了一种超声编码信号作为激励,来提高对超声导波模式的识别.在附有表皮的长骨模型上,将基于基础序列调制的Golay码（BSGC）用于激励并产生超声弯曲导波信号.使得在远离换能器中心频率（200 kHz）的相对低频上（25 ～ 50 kHz）,激励产生了幅度相对较大的导波信号,通过二维傅里叶变换（2D-FFT）得到了与皮质骨厚度变化敏感的弯曲导波模式的相速度值.研究结果表明这种编码激励方式提高了接收信号的SNR,为评价皮质骨的厚度提供了重要依据.There is an increasing interest in using ultrasonic guided waves to assess long cortical bones. Soft-tissue coating on top of the bone makes, however, the related in vivo application difficult because of the low signal-to-noise ratio （SNR）. In order to improve the detection performance of guided waves, a base-sequence modulated Golay code （BSGC） is introduced on coated tubular bone phantoms. The proposed approach improves the SNR, so that the guided wave excitation from a custom-made 200 kHz piezo transducer was enabled at very low ultrasonic frequency （25 - 50 kHz） and with much higher amplitude. The phase velocities of the fundamental flexural guided wave （FFGW）, which are sensitive to the change of the cortical thickness, were obtained with the algorithm of 2 dimensional fast Fourier transform （2D-FFT）. Study results indicate that the proposed coded excitation method improves the SNR of the received signal and the obtained phase velocities provide important information to evaluate the thickness of the long bones.

关 键 词：编码激励 超声弯曲导波 信噪比 长骨 

分 类 号：R319[医药卫生—基础医学] R445.1