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Tunable-Q contourlet transform for image representation

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Journal of Systems Engineering and Electronics 2013年第1期24卷 147-156页

作者： Haijiang Wang Qinke Yang Rui Li Zhihong Yao Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources College of Urban and Environment Science Shanxi Normal University College of Urban and Environmental Sciences Northwest University College of Resources and Environment North China University of Water Resources and Electric Power

A novel tunable-quality-factor （tunable-Q） contourlet transform for geometric image representation is proposed. The Laplacian pyramid in original contourlet decomposes a signal into channels that have the same bandwidth on a logarithmic scale, and is not suitable for images with different behavior in frequency domain. We employ a new tunable-Q decomposition defined in the frequency domain by which one can flexibly tune the bandwidth of decomposition channels. With an acceptable redundancy, this tunable-Q contourlet is also anti-aliasing and its basis is sharply localized in the desired area of frequency and spatial domain. Our experiments in nonlinear approximation and denoising show that the contourlet using a better-suitable quality factor can achieve a more promising performance and often outperform wavelets and the previous contourlets both in visual quality and in terms of peak signal-to-noise ratio.

关键词： contourlet quality factor (Q-factor) anti-aliasing mul-tiscale decomposition.

Texture Feature Extraction Method for Ground Nephogram Based on contourlet and the Power Spectrum Analysis Algorithm

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Computers, Materials & Continua 2019年第8期61卷 861-875页

作者： Xiaoying Chen Shijun Zhao Xiaolei Wang Xuejin Sun Jing Feng Nan Ye College of Mechanical&Electrical Engineering Sanjiang UniversityNanjingChina Institute of Meteorology and Oceanography National University of Defense TechnologyNanjingChina Department of Civil Engineering Monash UniersityMelbourneAustralia

It is important to extract texture feature from the ground-base cloud image for cloud type automatic *** this paper,a new method is presented to capture the contour edge,texture and geometric structure of cloud images by using contourlet and the power spectrum analysis *** abundant texture information is *** images can be obtained a multiscale and multidirection *** coefficient matrix from contourlet transform of ground nephogram is *** energy,mean and variance characteristics calculated from coefficient matrix are composed of the feature *** frequency information of the data series from the feature vector values is obtained by the power spectrum *** Support Vector Machines(SVM)classifier is used to classify according to the frequency information of the trend graph of data *** is shown that altocumulus and stratus with different texture frequencies can be effectively recognized and further subdivided the types of clouds.

关键词： Ground nephogram super-wavelet contourlet the power spectrum

Web-based remote sensing image retrieval using multiscale and multidirectional analysis based on contourlet and Haralick texture features

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International Journal of Intelligent Computing and Cybernetics 2021年第4期14卷 533-549页

作者： Rajakumar Krishnan Arunkumar Thangavelu P.Prabhavathy Devulapalli Sudheer Deepak Putrevu Arundhati Misra School of Computer Science and Engineering Vellore Institute of TechnologyVelloreIndia School of Information Technology and Engineering Vellore Institute of TechnologyVelloreIndia School of Computer Science and Engineering Vellore Institute of TechnologyVelloreIndiaand Space Applications Centre AhmedabadIndia

Purpose-Extracting suitable features to represent an image based on its content is a very tedious *** in remote sensing we have high-resolution images with a variety of objects on the Earth’s *** distance metric is used to measure the similarity between query and database *** low distance obtained image is indexed at the top as high relevant information to the ***/methodology/approach-This paper aims to develop an automatic feature extraction system for remote sensing image *** texture features based on contourlet transform are fused with statistical features extracted from the QuadTree(QT)decomposition are developed as feature set to represent the input *** extracted features will retrieve similar images from the large image datasets using an image-based query through the web-based user ***-The developed retrieval system performance has been analyzed using precision and recall and F1 *** proposed feature vector gives better performance with 0.69 precision for the top 50 relevant retrieved results over other existing multiscale-based feature extraction ***/value-The main contribution of this paper is developing a texture feature vector in a multiscale domain by combining the Haralick texture properties in the contourlet domain and Statistical features using QT *** features required to represent the image is 207 which is very less dimension compare to other texture *** performance shows superior than the other state of art methods.

关键词： Image retrieval Remote sensing contourlet Texture features Web-based search CBIR Multiscale texture

A robust watermarking algorithm based on significant-tree in contourlet domain

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High Technology Letters 2008年第1期14卷 67-71页

作者：段贵多 Li Jianping Huang Tianxi School of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu 610054 P.R. China International Centre for Wavelet Analysis and Its Applications Logistical Engineering University Chongqing 400016 P.R. China No. 52 Research Institute of China Electronics Technology Group Corporation Hangzhou 310012 P.R. China

An adaptive algorithm operating in the contourlet domain is presented. contourlet is a new image sparse representation, which is better than a wavelet for piecewise smooth images with smooth contours. Because of flexible multiresolution, local and directional sensitivity of contourlet transform, our approach also defines significant-tree in the contourlet domain. By analyzing the relation of the contourlet coefficients, we embed the watermarking into all the coefficients of each significant-tree. Then referring to the statistical properties of the coefficients, the masking characteristics of texture are defined for adaptively controlling the embedding strength. Experimental results show that the proposed algorithm is highly robust to various attacks, such as JPEG compression, medium filtering, cropping and rotation. Furthermore, comparisons with a classical method in the wavelet domain prove the validity of the new algorithm.

关键词： contourlet sparse representation significant-tree masking characteristics

基于特征点模板的contourlet域抗几何攻击水印算法研究

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计算机学报 2009年第2期32卷 308-317页

作者：楼偶俊王钲旋吉林大学计算机科学与技术学院长春130023

抵抗几何攻击的数字水印是目前水印算法研究的热点与难点之一,一个微弱不可察觉的几何攻击就可能使绝大多数水印算法失效.文中对图像的contourlet变换特性进行了分析和讨论,在此基础上提出了一种以特征点为模板的基于contourlet的抗几... 详细信息

抵抗几何攻击的数字水印是目前水印算法研究的热点与难点之一,一个微弱不可察觉的几何攻击就可能使绝大多数水印算法失效.文中对图像的contourlet变换特性进行了分析和讨论,在此基础上提出了一种以特征点为模板的基于contourlet的抗几何攻击水印算法,包括:(1)在contourlet变换域最高阶方向子带的相同带内坐标中搜索纹理最丰富的位置作为嵌入位置,这样水印在被嵌入到图像重要区域的同时也保证其被嵌到纹理丰富的区域中;(2)根据嵌入点在低频对应位置的能量和高尺度同方向子带对应位置的纹理信息,确定了一种自适应的水印嵌入强度的策略,使得水印在嵌入位置和嵌入强度的选择上都保证了嵌入的水印具有很好的透明性和极大的鲁棒性;(3)改进了Harris-Laplace算子,利用该算子从含有水印的图像中提取出具有几何形变鲁棒性的特征点作为模板;(4)水印检测时,先利用特征点模板对应点之间的变换关系实现水印重同步,然后通过统计图像的相关性来验证水印的存在.仿真实验表明,所提出的水印算法不仅具有很好的透明性,而且对常见的图像处理和几何攻击具有很好的鲁棒性.

关键词：数字水印 contourlet 特征点模板几何攻击

基于contourlet域特征点的抗几何攻击水印方法

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计算机研究与发展 2010年第1期47卷 113-120页

作者：楼偶俊大连外国语学院软件学院大连116044

有效抵抗几何攻击的水印算法是目前水印技术研究的难点之一,很小的几何变形就可能使大多数水印算法失效.对图像contourlet变换和Harris-Affine算子的特性进行了分析和讨论,在此基础上提出了一种以仿射不变特征点的基于contourlet的抗几... 详细信息

有效抵抗几何攻击的水印算法是目前水印技术研究的难点之一,很小的几何变形就可能使大多数水印算法失效.对图像contourlet变换和Harris-Affine算子的特性进行了分析和讨论,在此基础上提出了一种以仿射不变特征点的基于contourlet的抗几何攻击水印算法.首先,用contourlet变换提取出多尺度、多方向的纹理信息;再用Harris-Affine检测算子从变换域的中、低频方向子带中提取出仿射不变特征点,结合自适应局部结构的特征尺度确定特征区域,并用U变换对其归一化处理,水印就自适应地嵌入到归一化后的区域中;水印嵌入采纳矢量量化的策略,将水印信息重复嵌入到不同方向子带、多个不相交的局部仿射不变特征区域.检测时,利用特征点实现水印的重同步,采用"多数原则"来提取水印的位信息,无需求助于原始图像.仿真结果表明,算法不仅具有较好的透明性。

关键词：几何攻击 contourlet Harris-Affine检测算子特征点自适应

基于contourlet域图谱聚类和多尺度Markov模型的多光谱遥感图像分割

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光电子．激光 2013年第5期24卷 999-1005页

作者：徐海霞温显斌邹永廖郑永春天津理工大学计算机视觉与系统教育部重点实验室天津市智能计算及软件新技术重点实验室天津300384 中国科学院国家天文台北京100012

针对多光谱遥感图像的特点,结合图谱聚类、contourlet系数分布的统计特性和多尺度Markov模型,提出了一种基于contourlet域图谱聚类和多尺度Markov模型的分割(CSCMMS)方法。首先对待分割图像进行contourlet变换,利用图谱聚类对最粗尺度... 详细信息

针对多光谱遥感图像的特点,结合图谱聚类、contourlet系数分布的统计特性和多尺度Markov模型,提出了一种基于contourlet域图谱聚类和多尺度Markov模型的分割(CSCMMS)方法。首先对待分割图像进行contourlet变换,利用图谱聚类对最粗尺度低频图像聚类得到可靠的初始分割结果;然后利用互信息构造contourlet域的多尺度Markov模型,结合多尺度、多方向的图像信息将低频图像的初始分割结果逐尺度传递到最细尺度,得到原始图像的分割。对合成图像和多光谱遥感图像的实验结果表明,提出方法在边缘信息保持和噪声敏感性上具有明显改进,错分率和运算时间进一步降低。

关键词：多光谱遥感图像分割 contourlet 图谱聚类多尺度Markov模型互信息

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一种contourlet图像块编码算法

铁道学报 2010年第4期32卷 56-62页

作者：张悦庭孟晓锋尹忠科王建英西南交通大学信息科学与技术学院四川成都610031

提出一种高灵活性、低缓冲的contourlet块编码算法。用临界采样的小波变换取代contourlet变换中的拉普拉斯塔式LP(Laplacian Pyramid)分解,得到非冗余的contourlet变换NRCT(Non-Redundant contourletTransform),使其更适合图像压缩。块编码中,每个子带被划分为相对小的码块,然后对各个码块独立编码,得到具有丰富实用特征集的码流,且明显降低了内存占用。合并NRCT同一小波子带中类似的方向频率划分,根据合并后方向子带的方向频率特性,得到改进的上下文模型。改进的上下文模型使NRCT块编码器中的MQ编码器输出码流码率更加接近其熵率,而JPEG2000上下文模型不能为该MQ编码器输入码流提供良好的条件概率估计。实验证明,特别是对于纹理丰富的图像,本文算法较基于JPEG2000上下文模型的NRCT块编码算法和JPEG2000算法,具有更高的压缩性能。

关键词：图像压缩小波 contourlet 上下文块编码

基于contourlet模极大值的图像边缘检测

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铁道学报 2008年第5期30卷 41-45页

作者：张悦庭孟晓锋尹忠科王建英西南交通大学信息科学与技术学院四川成都610031

现存的基于空间域或小波变换域图像边缘检测算法只能有效检测出图像有限方向的边缘。本文提出在contourlet变换子带上搜索模极大值的图像边缘检测算法。通过适当地调节变换各尺度上的分解级数得到具有抛物线型尺度的基,另使其满足方向... 详细信息

现存的基于空间域或小波变换域图像边缘检测算法只能有效检测出图像有限方向的边缘。本文提出在contourlet变换子带上搜索模极大值的图像边缘检测算法。通过适当地调节变换各尺度上的分解级数得到具有抛物线型尺度的基,另使其满足方向消失矩条件,则contourlet变换获得对图像中分片光滑边缘的最佳逼近。对原图像进行非下采样contourlet变换,然后对各子带进行阈值处理。由于contourlet变换子带不同于小波子带的全新特点,根据各方向子带代表的方向及其梯度方向,子带上各样本点与其梯度方向上相邻点比较模值即得变换系数模极大值。该算法不需经过复杂的连接模极大值点操作,亦可得到较高的边缘检测性能,较大地降低了计算复杂度。实验显示本文算法所提取的边缘更加逼近图像真实边缘,且具有较低的计算复杂度。

关键词：图像边缘检测小波 contourlet 模极大值