m序列编码激励超声成像的优化与评价

Evaluation and Optimization of Ultrasound Imaging Using the M-sequence Coded Excitation

对编码激励成像中应用的m序列进行了深入研究,包括压缩成像效果的定量评价以及波形旁瓣参数的优化处理。实验方法依据编码激励成像的基本原理,分别构建软件仿真系统和声学实验平台对不同长度的m序列进行压缩成像实验,并通过最优相位选择和维纳滤波处理来探求每级m序列可达到的最佳压缩参数。仿真结果表明：3级M序列优化结果可满足-30dB的普通成像,8级m序列可达到-40dB的高质量成像;声学实验表明：该优化方法使得平均旁瓣水平大约提高4-6dB,仅经滤波处理后的6级m序列可达到-33dB的RSLL值。

We studied the m - sequence used in coded excitation imaging. Performance of the m - sequence was examined with quantitative evaluation, and signal firings was optimized employing the filter technique. Based on the principle of ceded excitation, compression imaging system was constructed to simulate the imaging processes of m - sequences of different lengths, and acoustics experiment was conducted to verify the simulation results. The optimal compression parameter was achieved by applying the phase selection and wiener filter. The simulation results show that the m- sequence of level 3 can produce up to nearly - 30dB sidelobe level, and m - sequence of level 8 results in about - 40dB sidelobe level. The acoustics results reveal that the range sidelobe level （RSLL） is enhanced by 4 - 6 dB with the proposed method, and the m - sequence of level 6 can achieve - 33dB sidelobe level only by the use of wiener filter.