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一种基于模糊神经网络的Speckle图像滤波器

前 言在合成孔径雷达(SAR)生成的图像中,经常存在着Speckle噪声。该类噪声的高对比度和宽频带特性急剧地降低了对图像的理解和图像的分辨率,高速而有效地滤除这种噪声是SAR图像实时预处理中一个重要问题。线性滤波器易于分析和实现,在处理加性噪声时可以获得MSE准则下的最优解,但在处理非加性噪声如Speckle噪声和脉冲噪声时,常常失效。由于Speckle噪声是乘性噪声,故有文献称,可通过取对数的方法将Speckle噪声转换为类高斯噪声进行处理,但效果并不非常理想。因此,分析SAR图像的成像规律,获得Speckle噪声图像的数学模型,然后对其进行求解就成为必然[1,2 ,3 ,4]。由于SAR成像受诸多因素影响,这类方法经常因为模型偏差而失效。最新的方法是利用小波理论的时频联合特性来改进滤波器的效果[5,6] 。模糊理论和神经网络理论的发展,为SAR图像的滤波提供了一种新的方向[7] 。模糊技术能够将人类的认知规律直观地应用到滤...  (本文共5页) 阅读全文>>

《Journal of Zhejiang University Science》2003年02期
Journal of Zhejiang University Science

Digital speckle pattern interferometric measurement of diffusioncoefficients in hydrogels

INTRODUCTIONTherateofdiffusionofsurfactantsingelsisanimportantpropertybothforthecharacteriza tionofsolute gelinteractionsandforthedesignofnovelapplicationsofsuchmaterials (Kongetal.,1 997) .Conventionally ,diffusioncoeffi cientsingelsaremeasuredbymonitoringtheconcentrationofthediffusingsoluteinthesolu tionoutsidethegel.Holographicinterferometrytechniqueoffersapowerfultoolfornon contactmeasurement.Ithadbeenusedtomeasu...  (本文共4页) 阅读全文>>

《红外与激光工程》2016年09期
红外与激光工程

Taking the pulse of a plant:dynamic laser speckle analysis of plants

(1)The essential impossibility of control of the0 Introductionnatural environment in doing field experiments.As aresult data will inevitably contain artefacts resultingThe idea of monitoring the dynamic properties offrom changes to the environmental conditions.plant leaves via dynamic laser speckle analysis was(2)The low reflectivity of plant leaf surfacesinitially proposed and investigated in our previouswork[1],ins...  (本文共12页) 阅读全文>>

《Science China(Physics,Mechanics & Astronomy)》2012年06期
Science China(Physics,Mechanics & Astronomy)

Fabrication technique of micro/nano-scale speckle patterns with focused ion beam

The increasing miniaturization of devices, especially therapid development of Micro-Electro-Mechanical Systems(MEMS), has resulted in the demand for methods that canquantify minute loads or shapes and deformations at mi-cro/nano-scale [1-7]. Estimation of fundamental mechanicalproperties requires that displacements and strains be meas-ured at the micron and sub-micron length scale. One methodapplicable to micro/nano-...  (本文共8页) 阅读全文>>

《Science China Technological Sciences》2011年01期
Science China Technological Sciences

Analysis about the speckle of radar high resolution range profile

1 Introduction High resolution range profile (HRRP) represents the projec- tion of the complex echoes from the target scattering centers onto the radar line-of-sight (LOS). It is easier to be acquired than the inverse synthetic aperture radar (ISAR) image and has received intensive attentions [1–4]. Several issues have to be considered when HRRP is applied to ATR (automatic target recognition), the most important one...  (本文共11页) 阅读全文>>

《Optoelectronics Letters》2010年05期
Optoelectronics Letters

A method based on the average granulometric size of speckle for characterizing the scattering media

Since the laser speckle is a random phenomenon caused by very irregular spatial interference, it is mainly described statistically, such as by the contrast ratio and size[1]. Most researches on first-order statistical properties of speckle have demonstrated that the speckle contrast ratio is strongly re- lated with flow velocity[2], and it has been extensively inves- tigated for further applications in biological fun...  (本文共4页) 阅读全文>>