基于CONVEF的四阶各向异性扩散及图像去噪

偏微分方程在图像去噪中有广泛的应用。传统的二阶偏微分方程虽然具有较好的去噪效果,但是处理得到的结果容易产生阶梯效应,这种现象会引起后续图像处理的误判断。You和Kaveh提出了四阶偏微分方程,该模型可以有效的去除阶梯效应,但由于该算法是一个各向同性的滤波算法,因此图像的边缘保护能力有所降低,使去噪结果中边缘和纹理等细节信息丢失。针对以上缺点,提出了基于卷积虚拟电子场(CONVEF)的四阶偏微分方程。新的模型降低了图像在边缘方向的扩散,得到一个有效的各向异性扩散模型,从而在去噪的同时可以更好的保护图像的边缘、纹理等细节特征。     

结合分数阶偏微分和MCM模型的混合噪声去除方法

为了能够更好地去除混合噪声,在αβ?(ABO)图像去噪模型的基础上,提出了一种结合分数阶偏微分方程和MCM模型的混合噪声去除模型.该模型不仅能有效地去除图像中的椒盐噪声和高斯噪声,同时还可以较好地保留和增强图像中的边缘纹理信息.实验以峰值信噪比(PSNR)和均方根误差(RMSE)对去噪性能进行度量,证明了该方法的有效性.     

结合分数阶偏微分和MCM模型的混合噪声去除方法

为了能够更好地去除混合噪声,在αβ?(ABO)图像去噪模型的基础上,提出了一种结合分数阶偏微分方程和MCM模型的混合噪声去除模型.该模型不仅能有效地去除图像中的椒盐噪声和高斯噪声,同时还可以较好地保留和增强图像中的边缘纹理信息.实验以峰值信噪比(PSNR)和均方根误差(RMSE)对去噪性能进行度量,证明了该方法的有效性.     

基于边缘增强和稀疏表示的图像混合去噪算法

稀疏表示和非局部相似性在图像去噪领域扮演着越来越重要的角色,并且取得了很好的去噪效果.解决了高斯噪声和椒盐噪声混合的图像去噪问题.在去噪过程中,如何更好地保留图像中原有的边缘信息是一个很重要的问题.为此提出了在稀疏表示和非局部相似性的基础上,引入Sobel算子的算法.实验结果表明,该算法去噪效果突出,并且能够在去噪的同时保留图像的边缘信息,为去除图像中的混合噪声提供了一种有效的方法.     

一种新的变分消噪理论和算法研究

文章从梯度下降法解相应的欧拉方程着手,提出一种新的定参图像去噪方法.新方法在选取参数的同时又保证均值和方差估计式,并且得到了解偏微分方程新的初值.这个初值是噪声图像经过小波分解后的原低频系数和设置阈值的高频系数的重构图像.数值仿真结果表明,该方法选取的初值具有更好地去噪效果.     

基于改进型P＆M模型算法的图像去噪

高斯滤波算法在去噪时能平滑图像,但是会破坏图像的边缘细节,而基于PDE的各向异性扩散的P＆M模型算法在去噪时能保留图像的边缘细节,但是会出现零散的斑点。结合两种算法的优点,通过对扩散系数进行改进,提出一种改进型P＆M模型算法。仿真结果表明,该算法能够有效地去除噪声图像中的高斯白噪声和椒盐噪声,能够更好地保留图像的边缘细节,与高斯滤波算法和P＆M模型算法相比,改进型P＆M模型算法具有更好的去噪性能。     

一种混合噪声图像去噪的平滑算法

提出了一种新的混合滤波算法,对混有高斯和椒盐噪声的图像进行去噪处理.该算法首先对受椒盐噪声污染的像素点,采用自适应中值滤波算法进行去除;然后利用高阶统计量针对高斯噪声的不敏感特性,对受高斯噪声污染的像素点,采用其周围梯度和最小的几个点的灰度平均值来代替其灰度值去除噪声.实验结果表明,该算法能够在去除高斯和椒盐噪声的同时,保留更多的图像细节信息,特别是对感染较大噪声的图像有更好的去噪效果.     

一种新的4阶偏微分方程图像处理方法

提出了一种新的4阶偏微分方程去噪模型,与已有4阶偏微分方程模型、各向异性扩散模型、各向异性中值扩散模型和形态学扩散去噪模型相比较,该模型有效地权衡了噪声平滑效果和边缘保持,并通过数值算例验证了该模型的优越性.     

一种基于偏微分方程的图像去噪方法

为有效去噪,基于全变分及四阶偏微分方程图像去噪模型,提出一种图像综合去噪模型.该模型克服了全变分去噪模型带来的块效应以及四阶偏微分方程去噪模型在处理平滑区域时带来的不平坦现象.仿真结果表明,图像清晰度有了较大改善.     

基于PDE算法的指静脉图像预处理

为了更好地去除手指静脉图片中的噪声, 提出一种基于偏微分方程算法（PDE）的去噪新模型. 该模型在P M模型的基础上, 采用新的扩散函数, 并结合四阶PDE模型对原模型结构进行变换. 用合成图像和真实指静脉图像分别对新模型进行实验验证, 结果表明, 相对于P M模型, 新模型使信噪比（SNR）值提高了约5 dB, 且能在去除噪声的同时很好地保持指静脉特征.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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