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一种快速改进型SPIHT算法 被引量:10
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作者 邓宸伟 赵保军 《北京理工大学学报》 EI CAS CSCD 北大核心 2010年第4期478-482,共5页
在借鉴前人研究成果的基础上,对SPIHT算法进行如下改进:利用人眼视觉特性对小波系数进行加权,更加注重人的主观因素对图像压缩的影响;引入最大值表,系数扫描时只需将最大值表内相应数据同阈值进行比较;多颗空间方向树并行编码,加快算法... 在借鉴前人研究成果的基础上,对SPIHT算法进行如下改进:利用人眼视觉特性对小波系数进行加权,更加注重人的主观因素对图像压缩的影响;引入最大值表,系数扫描时只需将最大值表内相应数据同阈值进行比较;多颗空间方向树并行编码,加快算法执行速度.实验结果表明,与传统SPIHT算法相比,该算法编解码速度加快1倍以上,更易于硬件实现.所得重建图像具有更好的视觉感受,同时峰值信噪比平均高出0.2 dB. 展开更多
关键词 图像压缩 SPIHT算法 人眼视觉系统 最大值表 空间方向树
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The Second Type Singularities of Symplectic and Lagrangian Mean Curvature Flows 被引量:2
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作者 Xiaoli HAN Jiayu LI Jun SUN 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2011年第2期223-240,共18页
This paper mainly deals with the type II singularities of the mean curvature flow from a symplectic surface or from an almost calibrated Lagrangian surface in a K¨ahler surface.The relation between the maximum of... This paper mainly deals with the type II singularities of the mean curvature flow from a symplectic surface or from an almost calibrated Lagrangian surface in a K¨ahler surface.The relation between the maximum of the Kahler angle and the maximum of |H|2 on the limit flow is studied.The authors also show the nonexistence of type II blow-up flow of a symplectic mean curvature flow which is normal flat or of an almost calibrated Lagrangian mean curvature flow which is flat. 展开更多
关键词 Symplectic surface Lagrangian surface Mean curvature flow
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Integral Representation of Harmonic Function in a Half-Plane
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作者 李红伟 邓冠铁 《Journal of Mathematical Research and Exposition》 CSCD 2009年第4期662-670,共9页
In this article,we consider the integral representation of harmonic functions.Using a property of the modified Poisson kernel in a half plane,we prove that a harmonic function u(z) in a half plane with its positive pa... In this article,we consider the integral representation of harmonic functions.Using a property of the modified Poisson kernel in a half plane,we prove that a harmonic function u(z) in a half plane with its positive part u+(z)=max{u(z),0} satisfying a slowly growing condition can be represented by its integral of a measure on the boundary of the half plan. 展开更多
关键词 integral representation harmonic functions modified Poisson kernel.
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