基于参考台的盲源分离法在抑制地磁场近场噪音中的应用研究

随着城市建设的不断发展,地磁场观测受到的人文干扰越来越严重.汽车、地铁、高铁等产生的近场噪音造成了地磁脉动等空间场源信号难以被精确观测,严重影响了地磁观测资料的实际使用价值.因此抑制这些近场噪音、提取空间场源信号具有科学意义和应用价值.本研究将远场参考法和盲源信号分离法相结合,提出了一种能有效分离空间场源信号和近场噪音的方法.首先,基于仿真分析,我们准确分离了不同特征的源信号,阐明了此方法的有效性.然后,我们将该方法应用于日本千叶地区受电车干扰较为严重的实际磁场观测数据,并选用数据质量较高的KAK国际基准台作为远场参考,实现了地磁脉动和电车干扰信号的分离,并在此基础上对观测台站的近场噪音进行了抑制.这些结果表明基于参考台的盲源信号分离法在抑制近场噪音、提取地磁场信号中是有效的,可能在电磁法勘探中具有潜在的应用价值.

Experimental Research on the Double-peak Characteristic of Underwater Radiated Noise in the Near Field on Top of a Submarine

The double-peak characteristic of underwater radiated noise in the near field on top of the target submarine was analyzed in depth on the basis of submarine test data on the sea. The contribution of three major noise sources to the radiated noise of a submarine were compared and analyzed, and emphasis was put on the original source, production mechanism, and their correlative characteristics. On the basis of analysis on underwater tracking and pass through characteristics of the target submarine, the double-peak phenomenon was reasonably interpreted. Furthermore, the correctness of the theoretical interpretation was verified adequately in real submarine tests. The double-peak phenomenon indicates that the space distributing character on submarine radiated noise are both asymmetrical with time and space, whereas that is provided with directivity. Studying the double-peak phenomenon in depth has important reference value and meaning in engineering practice for understanding the underwater radiated noise field of submarines.

一种视频定位的远距离拾音装置

文章提出了一种视频定位的远距离拾音装置,目的在于提供一种可以有效增强视频监控画面指定目标音源品质,抑制近场音源干扰与噪音,简化后期降噪处理过程,安装使用方便的视频定位远距离拾音装置。包括指向性麦克风、全向麦克风,喇叭形桶体、主信号累加单元、噪声累加单元、后期信号处理单元,在每个喇叭形桶体内底端安装一个指向性麦克风、一个全向麦克风;后期信号处理单元对主信号与噪声信号进行减法处理得到目标语音信号;喇叭形桶体的开口面向目标声源平齐安装在以摄像头为中心的圆周上。此装置已申请中国国家专利局的专利。