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基于二维有偏距离插值的双层嵌入可逆信息隐藏算法
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作者 郭媛 晁恒 《燕山大学学报》 CAS 北大核心 2024年第5期428-436,共9页
针对目前可逆信息隐藏技术存在载密图像嵌入率与失真度无法兼顾的问题,提出一种基于二维有偏距离插值的双层嵌入可逆信息隐藏方案。第一层嵌入将图像像素按棋盘式划分为两组,采用改进的全向梯度参数结合二维有偏距离插值算法,用其中一... 针对目前可逆信息隐藏技术存在载密图像嵌入率与失真度无法兼顾的问题,提出一种基于二维有偏距离插值的双层嵌入可逆信息隐藏方案。第一层嵌入将图像像素按棋盘式划分为两组,采用改进的全向梯度参数结合二维有偏距离插值算法,用其中一组像素预测另一组像素,再按照预测误差扩展方式嵌入秘密信息。第二层嵌入将剩余一组像素作为目标像素,再进行预测和嵌入,进一步提高嵌入率。本文从算法可逆性、预测精度、嵌入容量和载密图像失真度等多方面进行实验分析,结果表明,双层嵌入恢复后图像峰值信噪比为∞,不同种类隐藏图像像素和恢复图像像素均方误差均为0,表明算法可实现完全可逆隐藏;对不同种类载体图像进行测试,测试图像平均预测误差绝对值小于4的比例为79%,表明算法预测精度高;嵌入率对比实验表明,与其他算法相比,本算法均为最高,且双层嵌入较单层嵌入率平均提升30%以上,充分利用了像素冗余性;嵌入率为0.7 bit/pixel时,本算法载密图像和原始图像的峰值信噪比平均为39.854 dB,高于同类算法3~5 dB,表明载密图像失真度更低。本文还对阈值与嵌入率、结构相似性与嵌入率之间的关联进行分析和对比实验,深入探讨了高嵌入率的获得条件。本算法可较好解决载密图像嵌入率和嵌入失真不平衡的矛盾,综合性能更优。 展开更多
关键词 可逆信息隐藏 预测误差扩展 二维有距离插值 全向梯度 双层嵌入
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改进的三角形上的Goodman-Said插值格式
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作者 战荫伟 《暨南大学学报(自然科学与医学版)》 CAS CSCD 1999年第5期55-58,共4页
对文[ Goodman , Said(1991)] 加以改进,使权函数更简单,从而复杂度更低改进后的格式仍然是一阶光滑的,并且算例表明。
关键词 样条 混合插值格式 偏插值 权函数 B-形式
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三维超声心动图空间任意方向断层图像的重建 被引量:1
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作者 周伟 杨新 +1 位作者 姚丽萍 孙锟 《上海交通大学学报》 EI CAS CSCD 北大核心 2002年第12期1829-1832,共4页
介绍了保边界的有偏距离加权同心插值法 ,在对三维超声心动图进行插值处理时 ,把三维规则不均匀的数据场变为规则均匀的数据场 .实验证明 ,该方法克服了常用的同心插值法的低通滤波特性带来的图像边缘模糊效应 ,其计算简单、运算速度快 ... 介绍了保边界的有偏距离加权同心插值法 ,在对三维超声心动图进行插值处理时 ,把三维规则不均匀的数据场变为规则均匀的数据场 .实验证明 ,该方法克服了常用的同心插值法的低通滤波特性带来的图像边缘模糊效应 ,其计算简单、运算速度快 ,为实现快速三维重建提供了必备条件 . 展开更多
关键词 三维超声心动图 距离加权同心插值 结构点图像 结构网格图像 断层图像 图像重建
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Application of Dynamic Track Drawing Algorithm in Ship Monitoring System
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作者 张峰 李四海 刘金 《Marine Science Bulletin》 CAS 2008年第2期89-96,共8页
The function of dynamic track drawing realized in the ship monitoring system. Based on the function, we could draw the sailing tracks dynamically according to the ship's orientation. Two kernel algorithms are involve... The function of dynamic track drawing realized in the ship monitoring system. Based on the function, we could draw the sailing tracks dynamically according to the ship's orientation. Two kernel algorithms are involved during the system developing process, i.e. the algorithms of angular deflection and distance interval value. The practice of system development shows that the proper application of these two algorithms has good effect'in the visualization of sailing track. 展开更多
关键词 angular deflection distance interval value ALGORITHMS GIS
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True-amplitude wavefield separation using staggered-grid interpolation in the wavenumber domain
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作者 杜启振 张明强 +2 位作者 陈晓冉 公绪飞 郭成锋 《Applied Geophysics》 SCIE CSCD 2014年第4期437-446,510,共11页
Wavefield separation of multicomponent seismic data to image subsurface structures can be realized in either the space domain or the wavenumber domain. However, as the particle velocity components used in the wavenumb... Wavefield separation of multicomponent seismic data to image subsurface structures can be realized in either the space domain or the wavenumber domain. However, as the particle velocity components used in the wavenumber-domain wavefield separation are not defined at the same grid point with the staggered-grid finite-difference method for elastic wavefield simulation, we propose the wavenumber-domain interpolation method to estimate the required values at the common grid points prior to the wavenumber-domain true-amplitude wavefield separation. Moreover, numerical experiments show that the wavenumber-domain interpolation method has high interpolation accuracy and the trueamplitude wavefield separation method shows good amplitude preservation. The application of the proposed methodology to elastic reverse-time migration can obtain good amplitudepreserved images even in the case of some velocity error. 展开更多
关键词 wavefield separation amplitude preservation staggered-grid finite difference wavenumber domain interpolation reverse-time migration
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A method of reconstructing complex stratigraphic surfaces with multitype fault constraints
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作者 Deng Shi-Wu Jia Yu +1 位作者 Yao Xing-Miao Liu Zhi-Ning 《Applied Geophysics》 SCIE CSCD 2017年第2期195-204,322,共11页
The construction of complex stratigraphic surfaces is widely employed in many fields, such as petroleum exploration, geological modeling, and geological structure analysis. It also serves as an important foundation fo... The construction of complex stratigraphic surfaces is widely employed in many fields, such as petroleum exploration, geological modeling, and geological structure analysis. It also serves as an important foundation for data visualization and visual analysis in these fields. The existing surface construction methods have several deficiencies and face various difficulties, such as the presence of multitype faults and roughness of resulting surfaces. In this paper, a surface modeling method that uses geometric partial differential equations (PDEs) is introduced for the construction of stratigraphic surfaces. It effectively solves the problem of surface roughness caused by the irregularity of stratigraphic data distribution. To cope with the presence of multitype complex faults, a two-way projection algorithm between three- dimensional space and a two-dimensional plane is proposed. Using this algorithm, a unified method based on geometric PDEs is developed for dealing with multitype faults. Moreover, the corresponding geometric PDE is derived, and an algorithm based on an evolutionary solution is developed. The algorithm proposed for constructing spatial surfaces with real data verifies its computational efficiency and its ability to handle irregular data distribution. In particular, it can reconstruct faulty surfaces, especially those with overthrust faults. 展开更多
关键词 Partial differential equation surface reconstruction INTERPOLATION fault MESHING
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三角形上的分片二阶光滑有理插值 被引量:1
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作者 余文波 战荫伟 《武汉大学学报(理学版)》 CAS CSCD 北大核心 2011年第3期250-254,共5页
给出三角形上一种C2插值格式,插值函数由偏插值函数加权求和而成.偏插值函数对应于每一个顶点:构造三角形的一种分割,在其上定义一个分片5次多项式,只插值该顶点及其相邻两边上的插值条件.对应于每一个顶点有一个权函数,它由重心坐标定... 给出三角形上一种C2插值格式,插值函数由偏插值函数加权求和而成.偏插值函数对应于每一个顶点:构造三角形的一种分割,在其上定义一个分片5次多项式,只插值该顶点及其相邻两边上的插值条件.对应于每一个顶点有一个权函数,它由重心坐标定义,是一个有理函数.所得的插值函数是一个分片有理函数,只需被插函数在三角形顶点处的直至2阶导数值,利用多项式的Bernstein-Bézier表示,该插值函数易于表达和计算. 展开更多
关键词 Berstein-Bézier形式 偏插值 二元样条 有理函数
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Multivariate Vector Valued Salzer's Theorem 被引量:3
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作者 陈之兵 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2003年第2期233-236,共4页
In this paper, the important Salzer's theorem for rational interpolation is generalized to the multivariate vector valued case.
关键词 MULTIVARIABLE rational interpolation Salzer's theorem.
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B-SPLINE PATCHES AND TRANSFINITE INTERPOLATION METHOD FOR PDE CONTROLLED SIMULATION 被引量:1
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作者 Yuanjie LIU Hongbo LI 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2012年第2期348-361,共14页
This paper is to discuss an approach which combines B-spline patches and transfinite interpolation to establish a linear algebraic system for solving partial differential equations and modify the WEB-spline method dev... This paper is to discuss an approach which combines B-spline patches and transfinite interpolation to establish a linear algebraic system for solving partial differential equations and modify the WEB-spline method developed by Klaus Hollig to derive this new idea. First of all, the authors replace the R-function method with transfinite interpolation to build a function which vanishes on boundaries. Secondly, the authors simulate the partial differential equation by directly applying differential opera- tors to basis functions, which is similar to the RBF method rather than Hollig's method. These new strategies then make the constructing of bases and the linear system much more straightforward. And as the interpolation is brought in, the design of schemes for solving practical PDEs can be more flexi- ble. This new method is easy to carry out and suitable for simulations in the fields such as graphics to achieve rapid rendering. Especially when the specified much faster than WEB-spline method. precision is not very high, this method performs 展开更多
关键词 B-spline representation finite element method RBF transfinite interpolation WEB-spline.
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