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为了提高MEMS陀螺仪测量精度,减少随机误差的影响,对产生随机误差的噪声源及其随机误差模型进行了分析;通过分析MEMS陀螺仪自身结构的缺陷并且对其输出数据进行了相应的滤波处理与平稳性检验,确立了合适的误差模型并利用Kalman滤波进行误差补偿,验证了模型的有效性;同时运用Allan方差法对MEMS陀螺仪噪声项进行了分析,确定了影响MEMS陀螺仪测量性能的主要因素以及比较了滤波前后的各项噪声源系数,检验了滤波效果且实验结果证明误差模型显著提高了MEMS陀螺仪的测量精度。 相似文献
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根据MEMS传感器中随机误差较大,有时会覆盖传感器中有用信号的问题,提出采用Allan方差方法对MEMS传感器实测数据进行分析。系统地分析了引起MEMS传感器误差的随机噪声种类及其来源和特性,Allan方差分析方法的优势不仅在于能确定各类随机误差的误差特性,而且可以确定出其误差系数,由此可与相应的各种滤波方法相结合更好地实现其滤波效果。实验证明:Allan方差分析是对MEMS传感器随机误差进行研究的有效方法。 相似文献
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针对由于MEMS陀螺随机误差较大而影响MEMS惯性测量系统测量精度的问题,提出一种利用Allan方差分析随机误差并建模的方法。在分析Allan方差原理的基础上,通过Allan方差分析法分离和辨识了MEMS陀螺仪的各项随机误差以及误差系数,并利用随机误差系数进行了数学建模。通过与ARMA模型比较,表明利用Allan方差建立的模型更加精确。该方法为MEMS惯性导航系统中姿态测量的误差补偿和滤波提供了新的思路,对提高MEMS惯性测量系统的测量精度具有一定的实际应用价值。 相似文献
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低成本MEMS陀螺实时滤波方法 总被引:1,自引:0,他引:1
为找到一种普遍适合低成本MEMS陀螺仪的随机误差实时处理方法,利用Allan方差分析法首先对MEMS陀螺仪进行分析,根据其误差特性进而设计了平均滤波算法以剔除粗大误差,然后使用最小二乘法,通过拟合前一段历史结果得到下一时刻输出的预测值,基于以上工作最终设计出Kalman滤波器对所输出进行滤波。由于将最小二乘法的推测作为预测过程,避免了系统状态模型难以准确建立的问题。该方法动态性能好,具有普适性。实验结果证明,该方法在静态和动态下均能有效工作,滤波后常值漂移被有效补偿,角度随机游走不再占误差的主要成分,均方差小于滤波前的十分之一。 相似文献
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地震仪测量的通常为水平分量,而对旋转分量的测量与研究还相对较少.单独运用陀螺仪测量振动的旋转分量,准确度不高,而且测量结果的漂移量较大.基于MEMS惯性器件的无陀螺捷联惯导技术或者陀螺仪-加速度计组合技术,为六自由度振动测量提供了便利.由于受其加工工艺的限制,MEMS惯性器件的测量精度还存在较大的差异,因此需要对MEMS惯性器件的误差特性进行对比测试与分析.文章应用Allan方差法对两种MEMS惯性器件的随机噪声进行了分析,得到了量化噪声、速度随机游走、零偏不稳定性、加速度随机游走、速率斜坡等5项随机噪声指标.随机噪声分析的结果表明,Allan方差法能有效地对MEMS惯性器件的随机噪声进行评估和分析. 相似文献
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针对惯导系统中MEMS加速度计输出漂移误差较大的问题,本文在对噪声分析建模的基础上,提出了一种小波阈值去噪优化算法.利用Allan方差分析加速度计输出噪声特性,构造噪声模型,并设计了一种基于多尺度阈值函数的去噪方法.该方法有效克服了传统软、硬阈值函数的局限性,且在各尺度上选取不同的调节系数优化滤波性能,算法适应性强.仿真结果表明,该方法在信噪比、均方根误差和波形相似度方面均有明显改善,较之传统阈值去噪算法信噪比提高了5 dB,并能在一定程度上提高系统导航精度,100 m范围内相对误差降低2.69%. 相似文献
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Andrea Stubbe Christoph Ringlstetter Klaus U. Schulz 《International Journal on Document Analysis and Recognition》2007,10(3-4):199-209
Given a specific information need, documents of the wrong genre can be considered as noise. From this perspective, genre classification helps to separate relevant documents from noise. Orthographic errors represent a second, finer notion of noise. Since specific genres often include documents with many errors, an interesting question is whether this “micro-noise” can help to classify genre. In this paper we consider both problems. After introducing a comprehensive hierarchy of genres, we present an intuitive method to build specialized and distinctive classifiers that also work for very small training corpora. Special emphasis is given to the selection of intelligent high-level features. We then investigate the correlation between genre and micro noise. Using special error dictionaries, we estimate the typical error rates for each genre. Finally, we test if the error rate of a document represents a useful feature for genre classification. 相似文献
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《IEEE transactions on audio, speech, and language processing》2006,14(1):110-122
An algorithmic variant of the conventional active noise equalizer (ANE), which independently controls some given frequencies of the primary signal, has been developed and extended to the multichannel case. The modified version of the ANE is named common-error multiple-frequency ANE. A detailed analysis of both multichannel equalizers has been carried out. From a convergence analysis in the frequency-domain, the significance of transducer locations in the behavior of a practical system can be predicted through the matrix of secondary path responses at each frequency. The ANEs steady-state transfer functions from the primary input signal to the noise output have also been developed and compared for different parameter settings and for accurate and inaccurate secondary path estimation. Furthermore, the multichannel extension of both equalizers has been implemented in a real-time active system inside a listening room for multifrequency noise. Useful-size zones of equalization have been binaurally measured by using a head and torso simulator. It was found that the common-error multiple-frequency ANE performs better than the conventional equalizer because it achieves a saving in computational complexity and has smaller overshoot. It can also be implemented in a real controller more easily than the conventional ANE and without showing meaningful differences in the practical results provided. 相似文献
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通常情况下,受脉冲噪声污染的图像采用中值滤波法复原,受高斯噪声污染的图像采用均值滤波法复原.为了去除两者的混合噪声,Lee和Kassam提出了一种改进的均值滤波算法Modified Trimmed Mean(MTM),但是MTM的使用受到了阈值的限制.为了在滤除退化图像中混合噪声的同时能更好地保护图像细节,我们详细分析了MTM滤波的特点,在对MTM进行改进的同时,提出了一种改进的自适应中值滤波算法(统计滤波).该算法无需噪声的先验知识,利用Visual C++自动搜索阈值来实现图像的最佳复原.利用两种客观标准进行评价,实践证明新方法的处理结果优于传统的MTM方法. 相似文献
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通常情况下,受脉冲噪声污染的图像采用中值滤波法复原,受高斯噪声污染的图像采用均值滤波法复原。为了去除两者的混合噪声,Lee和Kassam提出了一种改进的均值滤波算法ModifiedTrimmedMean(MTM),但是MTM的使用受到了阈值的限制。为了在滤除退化图像中混合噪声的同时能更好地保护图像细节,我们详细分析了MTM滤波的特点,在对MTM进行改进的同时,提出了一种改进的自适应中值滤波算法(统计滤波)。该算法无需噪声的先验知识,利用VisualC 自动搜索阈值来实现图像的最佳复原。利用两种客观标准进行评价,实践证明新方法的处理结果优于传统的MTM方法。 相似文献
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Feedback active noise control has been used for tonal noise only and it is impractical for broadband noise. In this paper, it has been proposed that the feedback ANC algorithm can be applied to a broadband noise if the noise characteristic is chaotic in nature. Chaotic noise is neither tonal nor random; it is broadband and nonlinearly predictable. It is generated from dynamic sources such as fans, airfoils, etc. Therefore, a nonlinear controller using a functional link artificial neural network is proposed in a feedback configuration to control chaotic noise. A series of synthetic chaotic noise is generated for performance evaluation of the algorithm. It is shown that the proposed nonlinear controller is capable to control the broadband chaotic noise using feedback ANC which uses only one microphone whereas the conventional filtered-X least mean square (FXLMS) algorithm is incapable for controlling this type of noise. 相似文献
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Adaptive noise smoothing filter for images with signal-dependent noise 总被引:20,自引:0,他引:20
Kuan DT Sawchuk AA Strand TC Chavel P 《IEEE transactions on pattern analysis and machine intelligence》1985,(2):165-177
In this paper, we consider the restoration of images with signal-dependent noise. The filter is noise smoothing and adapts to local changes in image statistics based on a nonstationary mean, nonstationary variance (NMNV) image model. For images degraded by a class of uncorrelated, signal-dependent noise without blur, the adaptive noise smoothing filter becomes a point processor and is similar to Lee's local statistics algorithm [16]. The filter is able to adapt itself to the nonstationary local image statistics in the presence of different types of signal-dependent noise. For multiplicative noise, the adaptive noise smoothing filter is a systematic derivation of Lee's algorithm with some extensions that allow different estimators for the local image variance. The advantage of the derivation is its easy extension to deal with various types of signal-dependent noise. Film-grain and Poisson signal-dependent restoration problems are also considered as examples. All the nonstationary image statistical parameters needed for the filter can be estimated from the noisy image and no a priori information about the original image is required. 相似文献
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Noise filtering is most frequently used in data preprocessing to improve the accuracy of induced classifiers. The focus of this work is different: we aim at detecting noisy instances for improved data understanding, data cleaning and outlier identification. The paper is composed of three parts. The first part presents an ensemble-based noise ranking methodology for explicit noise and outlier identification, named Noise- Rank, which was successfully applied to a real-life medical problem as proven in domain expert evaluation. The second part is concerned with quantitative performance evaluation of noise detection algorithms on data with randomly injected noise. A methodology for visual performance evaluation of noise detection algorithms in the precision-recall space, named Viper, is presented and compared to standard evaluation practice. The third part presents the implementation of the NoiseRank and Viper methodologies in a web-based platform for composition and execution of data mining workflows. This implementation allows public accessibility of the developed approaches, repeatability and sharing of the presented experiments as well as the inclusion of web services enabling to incorporate new noise detection algorithms into the proposed noise detection and performance evaluation workflows. 相似文献
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噪音强度的估计和去噪效果的评估 总被引:3,自引:1,他引:2
王景泉 《计算机工程与设计》2009,30(7)
若图像有较大的噪音,会影响视觉效果和有效信息的提取.常用的去噪方法在实际应用中都需要借助图像噪音强度去估计或控制去噪的效果.目前,我们常用的噪音强度估计方法中,没有考虑边缘像素点的影响,使估计值不很准确.把图像的边缘提取与噪音强度的估计相结合,提高了噪音强度估计的精度,并由此导出了去噪效果评估的一个新的数值客观标准算法,该评估方法不依赖在现实中不可知的标准图像,通过实验可以看出该标准具有很大的实用价值. 相似文献