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基于各向异性核扩散法的杨树叶特征降维 被引量:1
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作者 胡春华 李萍萍 《农业机械学报》 EI CAS CSCD 北大核心 2013年第11期281-286,共6页
对缺水与正常杨树苗叶片进行特征分析与降维处理。首先对样本进行光照补偿并去除奇异性;然后对样本数据空间进行归一化处理,提出采用基于各向异性核扩散法对缺水与正常样本数据空间进行降维,核参数采用最大类间距离法自适应调整;最后根... 对缺水与正常杨树苗叶片进行特征分析与降维处理。首先对样本进行光照补偿并去除奇异性;然后对样本数据空间进行归一化处理,提出采用基于各向异性核扩散法对缺水与正常样本数据空间进行降维,核参数采用最大类间距离法自适应调整;最后根据最大信噪比原则选择降维子空间维数,获得识别特征。分别对各向异性核扩散法、LE、LTSA以及PCA进行分析比较,对于叶脉较粗的杨树叶片,采用各向异性核扩散法效果较好,能保持空间的几何关系。采用SVM分类法对不同算法提取的特征进行分类,结果表明本文提出的算法提取的杨树叶特征分类效果较好。 展开更多
关键词 杨树叶 特征降维 各向异性扩散
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基于构造约束的波阻抗边界刻画 被引量:4
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作者 张宏兵 杨长春 尚作萍 《地球物理学进展》 CSCD 北大核心 2007年第3期817-825,共9页
通过边界保护正则化和约束反演,在反演的目标函数中引入各种先验信息约束,以解决波阻抗反演的病态问题和带限问题.为了克服波阻抗模型边界过于平滑,在反演中引入地层和断层等构造信息约束,并且通过调整地层分界面和断层处的正则参数值... 通过边界保护正则化和约束反演,在反演的目标函数中引入各种先验信息约束,以解决波阻抗反演的病态问题和带限问题.为了克服波阻抗模型边界过于平滑,在反演中引入地层和断层等构造信息约束,并且通过调整地层分界面和断层处的正则参数值来实现构造约束.此外,采用各向异性扩散法进行平滑处理,改善反演结果.通过合成数据测试和实际资料反演,证明了本文提出的方法对刻画模型边界是有效的. 展开更多
关键词 波阻抗反演 构造约束 正则参数 各向异性扩散法
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FILTERING OF MEDICAL ULTRASONIC IMAGES BASED ON A MODIFIED ANISTROPIC DIFFUSION EQUATION 被引量:3
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作者 Wang Ling Li Deyu +4 位作者 Wang Tianfu Lin Jiangli Peng Yun Rao Li Zheng Yi 《Journal of Electronics(China)》 2007年第2期209-213,共5页
Speckle noise reduction is a key problem of the image analysis of medical UltraSound images. In this paper, two important improvements have been developed to a fast anisotropic diffusion algorithm for speckle noise re... Speckle noise reduction is a key problem of the image analysis of medical UltraSound images. In this paper, two important improvements have been developed to a fast anisotropic diffusion algorithm for speckle noise reduction. The Gaussian filter is firstly used before gradient calculation, and then the adaptive algorithm of the factor k is proposed. Numerous experimental results show that the proposed model is superior to other methods in noise removal, fidelity and edge preservation. It is suitable for the preprocessing of a great number of medical UltraSound images, such as three dimen- sional reconstruction. 展开更多
关键词 Diffusion equation Edge detection Image procession Speckle denoise
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Research on Computer Image Enhancement and Image Scratch Repair
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作者 Haifeng Wang 《International Journal of Technology Management》 2013年第1期100-102,共3页
In general there is a digital image with noise, low contrast, blnrred edges and other defects. To effectively enhance the contrast of the image blur to meet the requirements of the subsequent identification and detect... In general there is a digital image with noise, low contrast, blnrred edges and other defects. To effectively enhance the contrast of the image blur to meet the requirements of the subsequent identification and detection. This paper presents a fuzzy adaptive image contrast enhancement algorithm based on gray entropy. This method not only enhances the overall image contrast, but also effectively enrich the target image detail information, and suppress the noise amplification. Meanwhile, the paper proposes an improved K and P parameters image restoration algorithm. The algorithm combines both isotropic and anisotropic diffusion, the use of regional differences in the frequency achieved in the different regions use different iterative equation. Experimental results show that the algorithm with TV model algorithm compared with the same premise of restorative effects, avoiding the staircase effect and better than the TV model repair speed. 展开更多
关键词 Image restoration image enhancement ANISOTROPY TV model
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Anisotropic diffusion filtering for ultrasound speckle reduction 被引量:2
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作者 GUAN FaDa TON Phuc +1 位作者 GE ShuaiPing ZHAO LiNa 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第3期607-614,共8页
Speckle noise has long been known as a limiting factor for the quality of an ultrasound B-mode image.In this study,anisotropic diffusion filtering is proposed as an effective method for ultrasound speckle reduction.Th... Speckle noise has long been known as a limiting factor for the quality of an ultrasound B-mode image.In this study,anisotropic diffusion filtering is proposed as an effective method for ultrasound speckle reduction.This article provides a brief description of anisotropic diffusion filtering proposed by Perona and Malik,and compares its speckle filtering effects with other filtering methods including median,moving average,and frequency domain Gaussian low-pass.In this study,multiple filters are implemented in Matlab.For each filter,three different types of noisy images with speckle noise are tested.The results show that anisotropic filter can reduce the noise more effectively and meanwhile preserve the boundaries of the objects.In addition,this filter has more controllable filtering parameters and is independent on the information of the noise. 展开更多
关键词 anisotropic diffusion filter ULTRASOUND speckle reduction
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