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This paper proposes a spatially denoising algorithm using filtering-based noise estimation for an image corrupted by Gaussian noise.The proposed algorithm consists of two stages:estimation and elimination of noise density.To adaptively deal with variety of the noise amount,a noisy input image is firstly filtered by a lowpass filter.Standard deviation of the noise is computed from different images between the noisy input and its filtered image.In addition,a modified Gaussian noise removal filter based on the local statistics such as local weighted mean,local weighted activity and local maximum is used to control the degree of noise suppression.Experiments show the effectiveness of the proposed algorithm. 相似文献
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An spatially adaptive noise detection and removal algorithm is proposed.Under the assumption that an observed image and its additive noise have Gaussian distribution,the noise parameters are estimated with local statistics from an observed degraded image,and the parameters are used to define the constraints on the noise detection process.In addition,an adaptive low-pass filter having a variable filter window defined by the constraints on noise detection is used to control the degree of smoothness of the reconstructed image.Experimental results demonstrate the capability of the proposed algorithm. 相似文献
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依据噪声特点以及图像的像素关联性,提出了一种有效的数字图像混合噪声滤波算法。该算法首先对图像像素进行检测,依据受脉冲噪声污染的图像像素与其周围邻域多数像素在亮度上具有显著差异的特点准确检测出脉冲噪声,然后以检测到的脉冲噪声为被处理像素,用其邻域内未被脉冲噪声污染的图像像素对其进行中值滤波,由于当前脉冲噪声点以及邻域脉冲噪声点均未参与滤波运算,从而较好地保护了图像的细节。对图像中的高斯噪声,提出了一种改进的加权均值滤波算法,该算法在定义相关度函数时,既考虑了像素的灰度相关性,又考虑了像素的位置相关性。实验结果表明:提出的混合噪声滤波算法不仅可以有效滤除图像中的混合噪声,而且还可以较好地保护图像的细节。 相似文献
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对风机设计中的降噪方法进行了研究,并应用于自行研制的矿用子午加速局部通风机中,通过实验证明,以此方法设计的风机与相同转速和直径的局部风机相比,降噪效果较好。 相似文献
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针对枪口烟雾图像的不规则性以及烟雾扩散速度快等特点,传统的边缘检测算法无法高效地提取烟雾边缘轮廓的问题,对烟雾图像采集技术、烟雾图像预处理技术以及烟雾图像边缘检测技术进行了研究,提出了一种改进的二进小波和抗噪形态学融合的边缘检测算法.首先,在 B 样条二进小波基础上,将二进小波消失矩的阶数提高到四阶;其次,选取方向不同的结构元素,得出改进的形态学算子;最后,用小波逆变换重新构造枪口烟雾图像,对其进行锐化处理,输出边缘信息.仿真结果表明,该算法检测出来的枪口烟雾图像边缘定位准确且清晰完整,能有效抑制噪声,在客观方面优于传统的边缘检测算法. 相似文献
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Nailong ZHANG Wentong YANG Renyuan FEI 《Frontiers of Mechanical Engineering in China》2008,3(4):377-384
Currently, noise pollution is an environmental problem all over the world. The health and life of human beings are affected
by loud noise from high power generator sets. To reduce such noise, a sound-attenuated enclosure is widely used for its high
performance and convenient usage. By installing equipment in an enclosure, noise is controlled and prevented from radiating.
In this paper, noise control techniques for enclosures are presented. Enclosure development trends are predicted. 相似文献
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对某离心泵作透平流体诱发的内场噪声特性进行数值计算和试验研究。在典型流量下,采用雷诺时均方法获取壳体壁面偶极子声源,并利用边界元方法(Boundary element method,BEM)求解出壳体偶极子源作用的流动噪声,基于有限元结合边界元的声振耦合法(Finite element method/boundary element method,FEM/BEM)计算出流体激励结构振动产生的内场流激噪声及考虑结构振动的流动噪声,分析不同性质噪声源的频谱特性,同时评估内场声源在各个频段下的贡献量。借助水听器对透平出口进行流体声学试验,获得了噪声的频谱特性。结果表明,离心泵作透平出口流体诱发噪声主要集中在中低频段,小流量工况低频噪声特性增强。壳体声源作用下考虑结构振动流动噪声的计算结果与试验结果在较大流量下吻合较好。壳体偶极子作用的流动噪声对内场噪声的贡献最大,其次是考虑结构振动的流动噪声,流激噪声对内场噪声贡献最小。结构的影响使得二阶叶频处声压增加,其余离散频率及宽频处声压均有所降低。该研究结果为低噪声叶轮机械设计提供了一定的参考。 相似文献
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表面肌电信号测试中工频干扰的抑制 总被引:6,自引:0,他引:6
介绍了一种表面肌电信号 (EMG)测试调理电路和信号处理的方法。表面EMG测量中最难处理的问题之一是工频(5 0Hz)干扰 ,它处在有效的肌电信号频带之中。针对表面EMG的测量特点设计了一种信号调理电路 ,使肌电信号和工频信号并行单独处理 ,避免了不加区分地采用工频陷波器 ,这一设计思想在实际的肌电信号检测时取得了较好的实验结果。 相似文献
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Based on the characteristics of impulse noises,the authors establish a new filter,Iterative Adaptive Median Filter (IAMF).According to the charactics of images polluted by impulse noises,they establish weight ftnction combined with iterative algorithm to eliminate noises.In IAMF filter process,because the noise spots do not participate in the computation,they do not influence the normal points in the image,therefore IAMF can retain the detail well,maintain the good clarity after processing image,and simultaneously reduce the computation.Experiments showed that IAMF have ideal denoising effect for the images polluted by the impulse noises;especially when the noise rates are more than 0.5,IAMF is more prominent,even when the noise rates are more than 0.9,IAMF can achieve a satisfactory results. 相似文献
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本文阐述了齿轮噪声产生的机理,根据齿轮的发声机理将齿轮噪声分为加速度噪声和自鸣噪声,并用实验研究加速度噪声和自鸣噪声.本文采用隔声罩和传声管成功地将两种噪声分离,验证了理论分析的结果. 相似文献
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引进了局部辐射噪声比例系数的概念,用表面局部振动速度代替平均表面速度进行辐射噪声比例系数计算,以此来对该局部声辐射强度进行定量分析。这种方法使结构声源的识别过程得到很大简化,更适合工程实际需要。通过应用实例分析证明,该方法能快速准确地确定结构声在总噪声中的地位和结构的具体发声部位。 相似文献
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A number of techniques have been proposed during the last three decades for noise variance and signal‐to‐noise ratio (SNR) estimation in digital images. While some methods have shown reliability and accuracy in SNR and noise variance estimations, other methods are dependent on the nature of the images and perform well on a limited number of image types. In this article, we prove the accuracy and the efficiency of the image noise cross‐correlation estimation model, vs. other existing estimators, when applied to different types of scanning electron microscope images. SCANNING 35: 205‐212, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
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为获取减振器以某种概率产生某种程度异响时底层设计变量的取值区间,提出了基于广义逆推算法的减振器抗异响设计。以某型轻微异响(普通乘员可察)减振器为例,建立了对异响贡献度较高的7个设计参数与减振器杆端加速度有效值间的映射关系:条件受限玻尔兹曼机(Conditional Restricted Boltsmann Machines,CRBM)与深度信念网络(Deep Belief Network,DBN)相结合的CRBM-DBN近似模型,进而通过智能优化算法和区间搜索技术求解了设计参数的最优区间。对3支参数组合比较典型的的优化样件进行台架试验及整车主观感受,结果表明:优化样件的异响程度降低明显,进一步验证了减振器抗异响设计思路的有效性。 相似文献