麦克风阵列语音增强技术及其应用

本文简要叙述了应用麦克风阵列进行语音增强的原理及方法。且由于麦克风阵列在实际语音处理时具有良好的拾取语音能力及噪声鲁棒性,本文将介绍该技术在车载系统环境、机器人语音识别、大型场所的记录会议、助听装置及声源定位等系统中的应用。     

Piezoelectric cantilever microphone and microspeaker

A micromachined piezoelectric cantilever transducer, which works both as a microphone and as a microspeaker, has been fabricated and tested. The 2000×2000×4.5 μm³ cantilever has a zinc oxide (ZnO) piezoelectric thin film on a supporting layer of low-pressure chemical-vapor-deposited (LPCVD) low-stress silicon nitride. A highlight of the fabrication process, which may also be relevant for other micromachined structures, is the technique for producing a flat, multilayer cantilever. The measured microphone sensitivity is fairly constant at 3 mV/μbar in the low frequency range and rises to 20 mV/μbar at the lowest resonant frequency of 890 Hz. The 3 mV/μbar sensitivity is the highest reported to date for a microphone with a micromachined diaphragm. When measured into a 2 cm³ coupler with 4 V(zero-peak) drive, the microspeaker output sound pressure level (SPL) is 75 dB at 890 Hz. It increases to approximately 100 dB SPL at 4.8 kHz with 6 V(zero-peak) drive. The measured microphone frequency response agrees well with the results of an ABAQUS simulation     

微声传感器在低空飞行器信号采集系统中的应用

提出了一种基于微声传感器阵列的低空飞行器信号采集方案.为满足无人值守,不间断、长时间工作的要求,采用集成化的设计思想设计了体积小、低功耗的声信号采集电路,并在此基础上提出了一种能满足恶劣环境使用要求的微声传感器封装方法,设计了微型防护咪头.进行了机场实地采集试验,该声信号采集系统在机场进行了实地数据采集实验,并使用MATLAB软件将采集到的数据进行了分析对比,结果表明本文设计的微声传感器在低空飞行器信号采集系统中的应用效果良好.     

2D sound source position estimation using microphone arrays and its application to a VR-based bird song analysis system

ABSTRACT

This paper addresses the problem of 2D sound source localization using multiple microphone arrays in an outdoor environment. Two main issues exist in such localization. Since the localization performance depends on a variety of parameters, the lack of knowledge about how to design the system is one of those issues. A thorough analysis in respect to the accuracy of the localization results with different simulation conditions has been performed. Obtained characteristics lead to a discussion on limitations and applicability of the system. The distinction between multiple simultaneous sound sources is another problem. This is directly related to the appearance of outliers in the localization process. To solve this issue, an outlier removal method is proposed, which takes the properties of the observed sounds into consideration. In this paper a VR-based visualization method of the obtained results is also introduced. As the application scenario, we selected bird song analysis, which provides a challenging environment in terms of constantly changing signal-to-noise ratio and relative sensor-to-target position. A prototype system has been established using the proposed method. Several simulation results have been presented followed by a discussion on the issues. This leads to establishing system design guidelines that ensure a predictable performance.     

Piezoelectric microphone with on-chip CMOS circuits

An IC-processed piezoelectric microphone with on-chip, large-scale integrated (LSI) CMOS circuits has been designed, fabricated, and tested in a joint, interactive process between a commercial CMOS foundry and a university micromachining facility. The 2500×2500×3.5 μm ³ microphone has a piezoelectric ZnO layer on a supporting low-pressure chemical-vapor-deposited (LPCVD), silicon-rich, silicon nitride layer. The optimum residual-stress-compensation scheme for maximizing microphone sensitivity produces a slightly buckled microphone diaphragm. A model for the sensitivity dependence of device operation to residual stress is confirmed by applying external strain. The packaged microphone has a resonant frequency of 18 kHz, a quality factor Q≈40, and an unamplified sensitivity of 0.92 mV/Pa. Differential amplifiers provide 49 dB gain with 13 μV A-weighted noise at the input     

FPGA based dual microphone speech enhancement

Microsystem Technologies - This paper proposes an efficient reconfigurable hardware design of dual microphone speech enhancement technique using sound source localization and multi band spectral...     

基于麦克风阵列的语音增强算法

为解决现有语音增强算法需要麦克风数量较多和受估计误差影响较大的问题,提出一种改进的声源定位和波束形成方法。在现有声源定位算法利用时间延迟的基础上,引入能量衰减参数,实现利用双麦克风进行声源定位的目标;在波束形成算法中引入加载系数,在出现协方差矩阵统计失配时仍可对期望方向聚焦,提高波束形成算法的鲁棒性。仿真结果表明,改进后的算法与传统算法相比具有更强的鲁棒性。     

Performance of speaker localization using microphone array

Speaker localization is a technique to locate and track an active speaker from multiple acoustic sources using microphone array. Microphone array is used to improve the speech quality of recorded speech signal in meeting room and other places. In this work, the time delay estimation between source and each microphone is calculated using a localization method called time differences of arrival (TDOA). TDOA localization consists of two steps namely (a) a time delay estimator and (b) a localization estimator. For time delay estimation, the generalized cross-correlation using phase transform, the generalized cross correlation using maximum likelihood, linear prediction (LP) residual and the Hilbert envelope of the LP residual are chosen for estimating the location of a person. A new speaker localization algorithm known as group search optimization (GSO) algorithm is proposed. The performance of this algorithm is analyzed and compared with Gauss–Newton nonlinear least square method and genetic algorithm. Experimental results show that the proposed GSO method outperforms the other methods in terms of mean square error, root mean square error, mean absolute error, mean absolute percentage error, euclidean distance and mean absolute relative error.     

基于麦克风阵列声音信号定位方法的研究

提出了一种在嘈杂环境下利用麦克风阵列对声音信号定位的方法。该方法对每个麦克风采集的声音信号进行经验模态分解,然后根据各个IMF信号的归一化能量挑选出主要的IMF分量进行信号重构,从而实现对信号进行降噪处理。将降噪后的信号使用互功率谱相位法进行相关运算,计算出不同麦克风声音信号出现的时间差异。根据信号时延和麦克风之间的几何位置关系计算出声音信号的位置。为了验证本文所提出的定位算法,进行了语音信号定位实验,通过实验实测的数据分析对比分析,验证了本文提出的方法比传统的定位算法要优越。     

基于麦克风阵列和虚拟仪器的声源定位

对基于麦克风阵列的声源定位技术进行了研究,分析了时延估计算法的构成方法,在此基础上提出了用于二维DOA估计的双曲线算法。利用传声器MPA416和数据采集卡PXI4472结合Labview虚拟仪器实现了对声源的二维DOA估计。实验证明,该系统定位实时性好、准确度高。     

Web应用开发中构件描述的研究与应用

为了有效地利用已存在的资源和开发成果提高Web应用开发的效率,在软件复用思想的基础上,提出一种基于构件的Web应用开发方法.该方法从系统建模开始,说明了使用构件技术开发Web应用的流程.总结了Web应用开发时可能用到的各种构件类型,并提出了一种基于XML的构件及其依赖关系的描述方法,使开发人员不必了解构件内部的实现细节就能开发出高效健壮的系统.最后通过一个登录模块的实例,表明了该方法的可行性.     

Object-oriented Web application development

Most Web applications are still developed ad hoc. One reason is the gap between established software design concepts and the low-level Web implementation model. We summarize work on WebComposition, a model for Web application development, then introduce the WebComposition Markup Language, an XML-based language that implements the model. WCML embodies object-oriented principles such as modularity, abstraction and encapsulation     

Web应用开发方法研究

随着Web技术的快速发展,Web应用规模的扩大,系统、成熟的开发方法对成功的构建Web应用系统显得越来越重要。本文分析了Web应用开发方法应有的一些特性,简单介绍了一些主流的Web应用开发方法。最后以一个相对比较成熟的Web应用开发方法 Web ML为例,对它的建模元素、开发过程以及支持工具进行了详细的研究。     

面向膜电极的选择性生成纳米级多孔硅技术的研究

研究了面向微型燃料电池膜电极的多孔硅薄膜的制备工艺.多孔硅刻蚀工艺高效便宜,与标准CMOS工艺兼容.通过选择不同的衬底掺杂浓度和适当的电解液浓度能控制纳米(或微米)级多孔硅的孔径大小,得到适用于膜电极的纳米级孔径的多孔硅薄膜,证实了纳米级多孔硅可用于硅微燃料电池中膜电极的可能性.     

生物传感器的应用现状与发展趋势

生物传感器是一种以生物活性单元为敏感元件,结合化学、物理转换元件,对被分析物具有高度选择性的装置,它具有灵敏度高、检测速度快、操作简便、成本低、可进行连续动态监测等优点。在介绍生物传感器发展现状、组成及工作原理的基础上,对生物传感器在生命科学、医学、环境检测、食品工程及军事等领域中的应用研究进行了综述,并探讨了生物传感器的发展前景。     

选煤厂监控系统开发与应用

针对李子垭选煤厂的选煤工艺特点,采用计算机与P L C相接合的控制技术、现场总线通信技术并辅以视频监控技术,对选煤厂生产过程的监控系统进行研究、设计和开发。系统以P L C作为控制层核心,以工控计算机、工业以太网和组态软件作为管理层,以现场总线和各种自主研发的矿用本安传感器作为设备层,构建起三层网络结构,实现集中控制和信息化管理。该选煤厂监控系统已投入使用,运行表明,该系统不仅功能完善,而且提高了选煤厂生产效率,保障了生产安全和产品质量。     

无线网络现场总线系统的开发与应用

主要叙述火电站发电机组的辅机程控技术进行智能化设计,增加无线网络技术对I／O设备、现场总线设备、蓝牙等设备进行控制及相关软硬件配置。     

WDM驱动程序的开发与实现

WDM是在WindowsNT4．0驱动程序结构上发展起来的．WDM体系结构实行分层处理，是一种通用的驱动模式，提供了包括USB、IEEE1394和HID等在内的一系列驱动程序类。文章描述了WDM驱动程序的体系结构和利用DriverStudio开发WDM驱动程序的过程．给出了一个USB驱动的实例。     

Design and fabrication of silicon condenser microphone usingcorrugated diaphragm technique

A novel silicon condenser microphone with a corrugated diaphragm has been proposed, designed, fabricated and tested. The microphone is fabricated on a single wafer by use of silicon anisotropic etching and sacrificial layer etching techniques, so that no bonding techniques are required. The introduction of corrugations has greatly increased the mechanical sensitivities of the microphone diaphragms due to the reduction of the initial stress in the thin films, For the purpose of further decreasing the thin film stress, composite diaphragms consisting of multilayer (polySi/Si_xN_y/polySi) materials have been fabricated, reducing the initial stress to a much lower level of about 70 MPa in tension. Three types of corrugation placements and several corrugation depths in a diaphragm area of 1 mm² have been designed and fabricated. Microphones with flat frequency response between 100 Hz and 8~16 kHz and open-circuit sensitivities as high as 8.1~14.2 mV/Pa under the bias voltages of 10~25 V have been fabricated in a reproducible way. The experimental results proved that the corrugation technique is promising for silicon condenser microphone     

网络考试系统的开发及应用研究

论述了基于Web的网络考试系统的设计方法及主要功能,通过采用(C/S结构)、B/S结构为设计基础,数据库访问组件SQL进行数据库访问,开发了网络考试系统。在学院考试体系中进行应用展示了有良好的稳定性、扩展性及应用价值。