| 单边噪声源环境下的格林函数提取 |
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| 引用本文： | 黎洁,李国富,高大治,王宁.单边噪声源环境下的格林函数提取[J].声学学报,2017,42(2):143-151. |
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| 作者姓名： | 黎洁 李国富 高大治 王宁 |
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| 作者单位： | 1. 中国海洋大学海洋技术系 青岛 266100; |
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| 基金项目： | 国家自然科学基金项目(11374270,11374271)资助 |
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| 摘 要： | 对单边噪声源环境下空间中存在散射体时的格林函数到达时间结构提取展开了实验性研究。通过对位于沙滩上的传声器上记录的海浪噪声进行互相关处理,成功提取出两传声器间的格林函数到达时间结构。到达时间结构中观察到伪散射路径,并且伪散射路径在幅值上远高于散射路径。针对上述现象给出了理论及仿真解释:当传声器对受噪声源单边照射时,广义光学定理失效,伪散射路径将会出现;同时,由于伪散射路径由所有方向噪声源贡献,散射路径仅有稳相点附近声源贡献,因此伪散射路径在幅值上可能高于散射路径。结果表明,在单边噪声源环境下,基于互相关技术可以提取伪散射路径。伪散射路径的短时稳定提取可以为散射体无源成像提供更多信息,在海洋声学、地震学等领域具有潜在应用价值。
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| 关 键 词： | 环境噪声互相关 散射体无源成像 伪散射路径 散射路径 |
| 收稿时间： | 2015-09-24 |
Green's function retrieval in case of one-sided illumination |
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| Affiliation: | 1. Department of Marine Technology, Ocean University of China Qingdao 266100;2. National Ocean Technology Center Tianjin 300112;3. Qingdao Collaborative Innovation Center of Marine Science and Technology Qingdao 266100 |
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| Abstract: | We conduct an experiment about the retrieval of Green's function in case of one-sided illumination.By cross-correlating surf noise recorded on two receivers located on the beach,we obtain the arrival time structure of Green's function between these two locations.The spurious waves appear in the cross-correlation function,which are higher than the scattered waves in amplitude.Theoretical explanations of the above phenomena are given:When receiver pairs are illuminated by one-sided ambient noise,the spurious waves would appear due to the fact that the generalized optical theorem breaks down;meanwhile,the spurious waves are contributed by all the sources,so they might be higher than the scattered waves in amplitude.The result indicates that it is able to retrieve the spurious waves based on the cross-correlation technique when ambient noises are distributed on one side.The short time steady retrieval of spurious waves can be applied to scatterer passive imaging,with importantly application value for ocean acoustics and seismology study. |
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