共查询到17条相似文献,搜索用时 62 毫秒
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由于运动声源测量信号中多普勒效应的存在,一般声全息方法无法直接使用,而阵列信号波束成形处理方法无法进行定量分析.本方法建立了基于测量面、辐射面和全息面的运动学几何关系,提出了声源与测量信号之间的非线性时间映射方法,基于运动声源的声源特征函数,构造了消除多普勒效应的全息面时域声压分布.全息重建得到运动声源表面有效声压分布,实现了对主要声源处声压幅值的定量估计.实际运动声源的测量实验结果证明了该方法的有效性. 相似文献
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运动声源声场的可视化是一种重要的运动声源定位的技术手段,利用双目视觉测量技术实现运动声源声场空间的自动测量,自动确定运动声源表面的空间位置,针对声源表面,利用传声器阵列,基于声全息方法实现运动声源声场的重建,建立视频图像与声场的空间映射,并建立视频与声场之间的时序,实现实景视频图像与声场重建结果的融合,可以自动生成声源运动过程的视频。基于该方法所开发了一套试验测量系统,对运动声源的测量试验结果表明,该方法可以有效实现运动声源的视频可视化,使人可以直接从视频中看到声源及其变化过程,使声源的定位和识别变得更加简单。 相似文献
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基于被动合成孔径原理,提出了一种具有高稳健性的运动声源高分辨聚焦定位识别方法.该方法采用综合优化手段,通过矢量最大似然聚焦定位算法生成虚拟阵列坐标及数据矩阵,进而利用基于最差性能优化的稀疏虚拟阵列聚焦算法,获取稳健的高分辨定位识别效果.理论及仿真研究表明,该方法对于非匀速运动以及与基阵存在运动倾角的复杂情况具有较强的适用性,聚焦空间谱表现出更大的动态范围、更为尖锐的聚焦峰尺度以及更强的背景噪声起伏压制能力.湖上试验进一步验证,在高分辨最小方差信号无畸变响应法(MVDR)聚焦算法动态范围仅为3.5 dB的相
关键词:
稳健性
运动噪声源定位识别
矢量阵
最差性能优化 相似文献
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边界元法循环平稳近场声全息理论研究 总被引:2,自引:0,他引:2
循环平稳声场是工程中经常遇到的一种特殊非平稳声场,声压信号受到调制作用,导致频谱出现边带现象,经典的近场声全息技术重建得到的声场无法反映声场的调制特性。在平面循环平稳近场声全息基础上,提出一种边界元法的循环平稳近场声全息技术,用二阶循环统计量理论代替传统的傅里叶分析,并以声压的循环谱密度取代其频谱及功率谱密度作为重建量,可用于循环平稳声场中具有复杂表面声源的辐射声场。由于循环谱密度对循环平稳信号具有解调功能,用该方法重建得到的循环谱密度能有效地反映调制和载波信号的信息。仿真分析与实验表明了本理论的有效性和精度能满足工程要求。 相似文献
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在原有的平面循环平稳近场声全息基础上,提出一种基于波叠加法的循环平稳近场声全息技术,可以对具有复杂表面的声源进行全息重建,重建的声源表面声压谱相关密度函数能反映出调制信号的信息.声源表面声压谱相关密度函数全息图形象地反映了调制信号在表面的强弱分布情况,可由此确定调制信号源的产生位置.仿真分析和实验验证表明,基于波叠加法的循环平稳近场声全息技术可以更准确地反映循环平稳声场的调制特性.该方法继承了波叠加法的优点,无需计算边界奇异积分,计算效率高、精度好.
关键词:
近场声全息
循环平稳信号
波叠加 相似文献
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在原有的平面循环平稳近场声全息基础上,提出一种基于波叠加法的循环平稳近场声全息技术,可以对具有复杂表面的声源进行全息重建,重建的声源表面声压谱相关密度函数能反映出调制信号的信息.声源表面声压谱相关密度函数全息图形象地反映了调制信号在表面的强弱分布情况,可由此确定调制信号源的产生位置.仿真分析和实验验证表明,基于波叠加法的循环平稳近场声全息技术可以更准确地反映循环平稳声场的调制特性.该方法继承了波叠加法的优点,无需计算边界奇异积分,计算效率高、精度好. 相似文献
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Cyclostationary sound field is a special kind of nonstationary sound field, in which the pressure signal is modulated seriously and sidebands exist in its spectrum. The reconstructed sound field can't figure the cyclostationary features in conventional Nearfield Acoustic Holography (NAH) procedure. On the basis of planar cyclostationary NAH, the cyclostationary NAH based on boundary element method is proposed which can be utilized to analyze radiators with complicated surface. Replacing the Fourier's transform with the second-order cyclic statistics, the Cyclic Spectral Density (CSD) functions is used as the reconstructed physical quantity in the proposed NAH technique, instead of the spectrum or power spectral density of pressure signal. By virtue of the demodulation ability of CSD function, the reconstructed CSD can effectively express the information of modulating and carrier wave respectively. The simulation and experiment illustrate that the validity and accuracy of this cyclostationary NAH technique satisfy the request of engineering. 相似文献
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The reconstruction of the acoustic field for general surfaces is obtained from the solution of a matrix system that results from a boundary integral equation discretized using boundary element methods. The solution to the resultant matrix system is obtained using iterative regularization methods that counteract the effect of noise on the measurements. These methods will not require the calculation of the singular value decomposition, which can be expensive when the matrix system is considerably large. Krylov subspace methods are iterative methods that have the phenomena known as "semi-convergence," i.e., the optimal regularization solution is obtained after a few iterations. If the iteration is not stopped, the method converges to a solution that generally is totally corrupted by errors on the measurements. For these methods the number of iterations play the role of the regularization parameter. We will focus our attention to the study of the regularizing properties from the Krylov subspace methods like conjugate gradients, least squares QR and the recently proposed Hybrid method. A discussion and comparison of the available stopping rules will be included. A vibrating plate is considered as an example to validate our results. 相似文献
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Nearfield acoustic holography in a moving medium based on particle velocity input using nonsingular propagator 下载免费PDF全文
Nearfield acoustic holography in a moving medium is a technique which is typically suitable for sound sources identification in a flow.In the process of sound field reconstruction,sound pressure is usually used as the input,but it may contain considerable background noise due to the interactions between microphones and flow moving at a high velocity.To avoid this problem,particle velocity is an alternative input,which can be obtained by using laser Doppler velocimetry in a non-intrusive way.However,there is a singular problem in the conventional propagator relating the particle velocity to the pressure,and it could lead to significant errors or even false results.In view of this,in this paper,nonsingular propagators are deduced to realize accurate reconstruction in both cases that the hologram is parallel to and perpendicular to the flow direction.The advantages of the proposed method are analyzed,and simulations are conducted to verify the validation.The results show that the method can overcome the singular problem effectively,and the reconstruction errors are at a low level for different flow velocities,frequencies,and signal-to-noise ratios. 相似文献
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The video visualization methods for moving sound sources are very important. The spatial positions in the sound filed measurement of moving sources arc measured by an automated method based on the binoculars stereo technique,the spatial coordinates of the surface of the moving sound source are determined automatically.The sound field of the surface of the moving source is reconstructed with a microphone array using the acoustic holography method for moving sound sources.The spatial mapping between the sound field and the video images is constructed,and also the time sequence of the sound field and the images is founded. Then,the reconstructed sound field and the real-world images are merged,and the visualized sound field video of the moving source is generated automatically.A sound field measurement system based on this method is developed,the measurement results of the moving sound source with this system indicate that the sound field video visualization is realized effectively with the proposed method,the sound sources and their changing process can be seen directly from the generated video,the identification and localization for the moving sound sources can be easier with this method. 相似文献