基于线形麦克风阵列的声源定位算法改进与噪声的实验分析

【作者】 王军；

【导师】 种兰祥；

【作者基本信息】 西北大学 ， 电路与系统， 2008， 硕士

【摘要】 人们对“声”的研究由来已久。随着科学技术的不断发展和研究手段的不断进步,音频信号处理这一方向又出现了许多新的热点与焦点。基于麦克风阵列的音频信号处理就是其中之一。因其自身优越的性能,开始被应用于许多新的领域,如视频会议、语音识别、车载系统、机器人控制、助听器、地震报警等。麦克风阵列的基本用途可以归纳为实现声源定位、跟踪与实现抗干扰语音增强两种。虽然这两种用途已经被人们广泛研究,但是依然有许多有待解决的问题。本文的主要工作就是对这两种基于麦克风阵列的语音信号处理方法所遇到的一些实际问题进行分析并提出改进解决方案。内容包括:1.简单介绍了麦克风阵列用于声源定位的几种常用方法与用于语音增强时的原理,讨论了它们的各自特点。2.对于延时累加可控波束形成方法中所遇到的对称双主瓣、空间角分辨率下降、频率选择性衰落等主要问题,提出了解决办法。计算机仿真结果说明,联合使用所提出的三个方法,可以提高室内线形全向麦克风阵列声源定位与跟踪的性能,而不必改变阵列拓扑结构、不增加硬件成本。3.在用于语音增强时,波束形成方法对于宽频带信号所对应的不同频点的空间带宽不同所带来的音色影响问题,讨论了一种恒定波束宽度方法并对已有方法进行改进。提高了运算速度,减小了系统开销,同时也达到了比较好的控制波束宽度的效果,并给出了计算机仿真结果。4.通过进行麦克风音频采集与数据处理实验所得到数据的归纳分析,总结出了工程实现中需要注意实际问题。得到了实际采集系统中噪声等因素对阵列信号处理的关键变量——信号相位的影响并归纳出一些解决方法。更多还原

【Abstract】 Although the research no sound has a long history, there are many new focuses with the continuous development of science and technology and the progress on the means of research. One of them is investigation on microphone array that has been applied to many areas because of its advanced character, such as video-conferences, hearing aid design, robot control, speech recognition, earthquake alarming and so on.The two common functions of microphone array are sound source localization/tracking and speech enhancement. A lot of work has been done about them, but the problems still exist. The contents of this thesis are as follows:1. The general methods based on microphone array for DOA (Direction of Arrival) and speech enhancement was introduced.2. The performance of linear microphone array was analyzed. And solutions to the problems that will occur when the microphone array serves for sound source localization and tracking in a closed environment was put forward. Using the three methods proposed together will improve the performance of the microphone array highly without either changing the topology of array or increasing additional hardware devices cost.3. An adaptive method based on microphone array to involve the constant beamwidth was introduced. And another method that can be faster was proposed. Both of them give the solutions to the problem that different frequencies make the beamwidth multiply.4. The data of a group of experiments was showed to find the character of real DAQ(data acquisition) environment. The noise which was involved by the circuit of DAQ system made the phases of signals inaccurate. The inaccurate phases impacted the result of the microphone array directly. Some solutions which were based on those experiments about inaccurate phase was put forward at the end of each experiments.更多还原