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超声乳腺肿瘤图像计算机辅助诊断系统 被引量:7
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作者 李晓峰 沈毅 王强 《吉林大学学报(工学版)》 EI CAS CSCD 北大核心 2009年第3期770-775,共6页
提出了一个基于异向扩散和支持向量机的超声乳腺肿瘤图像计算机辅助诊断系统。该系统提取了乳腺肿瘤图像归一化自相关系数、均方差系数、紧凑度等共26个纹理和几何特征。这些特征不但反映了乳腺良性肿瘤和恶性肿瘤本质的区别,而且考虑... 提出了一个基于异向扩散和支持向量机的超声乳腺肿瘤图像计算机辅助诊断系统。该系统提取了乳腺肿瘤图像归一化自相关系数、均方差系数、紧凑度等共26个纹理和几何特征。这些特征不但反映了乳腺良性肿瘤和恶性肿瘤本质的区别,而且考虑了医学超声图像为相干图像的特点。实验结果表明,该系统诊断精确度为93.48%,敏感性为94.3%,特殊性为52%,错误正比率为93.55%,错误负比率为93.4%,接受特性曲线下面积为0.9718,性能优于较有影响的文献[1]提出的方案。 展开更多
关键词 计算机应用 支持向量机 医学超声图像 计算机辅助诊断 异向扩散 特征提取 乳腺肿瘤诊断
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Microscopic phase-field study on directional coarsening mechanism caused by interaction between precipitates in Ni-Al-V alloy 被引量:4
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作者 杨坤 陈铮 +1 位作者 王永欣 范晓丽 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期193-200,共8页
A microscopic phase-field model was used to investigate a directional coarsening mechanism caused by the anisotropic growth of long period stacking and different effects of phases on precipitation in Ni-Al-V alloy.The... A microscopic phase-field model was used to investigate a directional coarsening mechanism caused by the anisotropic growth of long period stacking and different effects of phases on precipitation in Ni-Al-V alloy.The results show that DO22 mainly coarsens along its short axis,which may press the neighboring L12,leading to the interaction among atoms.Diffusion channels of Al are formed in the direction where the mismatch between γ' and γ reduces;the occupation probabilities are anisotropic in space;and direction coarsening of L12 occurs finally.With a rise of ageing temperature,phases appear later and DO22 is much later at a higher temperature,the average occupation probabilities of Al and V reduce,and Al changes more than V. 展开更多
关键词 nickel-based alloys microscopic phase-field simulation directional coarsening anisotropic growth MISMATCH diffusion
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AN IMAGE MAGNIFICATION ALGORITHM USING THE GVF CONSTRAINT MODEL 被引量:4
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作者 Li Xiaoguang Lam Kin-Man Shen Lansun 《Journal of Electronics(China)》 2008年第4期568-571,共4页
An image magnification method with a Gradient Vector Flow(GVF)constraint-basedanisotropic diffusion model is proposed in this letter.A Low-Resolution(LR)image is first magnifiedusing bilinear interpolation,and then an... An image magnification method with a Gradient Vector Flow(GVF)constraint-basedanisotropic diffusion model is proposed in this letter.A Low-Resolution(LR)image is first magnifiedusing bilinear interpolation,and then an iterative image restoration method,with the use of an ani-sotropic diffusion model and a Gaussian moving-average constraint,is applied to the magnified image.The estimated GVF of a High-Resolution(HR)image can be used to remove the jagged effect and topreserve the textural structure in the image.Meanwhile,the use of the Gaussian moving-average LRmodel can provide a data fidelity constraint,which renders a magnified image closer to the ideal HRversion.Experimental results show that the proposed method can improve the quality of magnifiedimages in terms of both objective and subjective criteria. 展开更多
关键词 Image magnification Super resolution Anisotropic diffusion Gradient-Vector Flow (GVF)
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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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β-Diketones at Water/Supercritical CO2 Interface: A Molecular Dynamics Simulation 被引量:2
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作者 刘淑延 柴景春 杨晓宁 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第6期990-998,共9页
The structural and dynamical properties of hexafluoroacetylacetone(HFA) and acetylacetone(AA) at the water/supercritical CO2(Sc-CO2) interface at 20 MPa and 318.15 K are investigated by molecular dynamics simulations.... The structural and dynamical properties of hexafluoroacetylacetone(HFA) and acetylacetone(AA) at the water/supercritical CO2(Sc-CO2) interface at 20 MPa and 318.15 K are investigated by molecular dynamics simulations.The TIP3P potential is used for water and the EPM2 model is for CO2.The water phase and SC-CO2 phase form a distinct immiscible liquid-liquid interface.The two chelating molecules show interfacial preference.Comparatively,the AA molecules show somewhat more preference for interfacial region,whereas the HFA molecules are preferably near the Sc-CO2 phase.The orientational distribution of the β-diketone molecules and the radial distribution functions between β-diketones and solvents are obtained in order to study the microscopic structural properties of the β-diketones at the water-SC-CO2 interface.It is found that the translational diffusion and rotational diffusion of HFA and AA are obviously anisotropic and decrease as the β-diketone molecules approach the interface.The anisotropic dynamic behavior for the solute molecules is related to the corresponding structural properties. 展开更多
关键词 molecular dynamics simulation liquid/liquid interface supercritical carbon dioxide Β-DIKETONE
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Noise Reduction of Welding Defect Image Based on NSCT and Anisotropic Diffusion 被引量:4
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作者 吴一全 万红 +1 位作者 叶志龙 刚铁 《Transactions of Tianjin University》 EI CAS 2014年第1期60-65,共6页
In order to reduce noise effectively in the welding defect image and preserve the minutiae information, a noise reduction method of welding defect image based on nonsubsampled contourlet transform(NSCT) and anisotropi... In order to reduce noise effectively in the welding defect image and preserve the minutiae information, a noise reduction method of welding defect image based on nonsubsampled contourlet transform(NSCT) and anisotropic diffusion is proposed. Firstly, an X-ray welding defect image is decomposed by NSCT. Then total variation(TV) model and Catte_PM model are used for the obtained low-pass component and band-pass components, respectively. Finally, the denoised image is synthesized by inverse NSCT. Experimental results show that, compared with the hybrid method of wavelet threshold shrinkage with TV diffusion, the method combining NSCT with P_Laplace diffusion, and the method combining contourlet with TV model and adaptive contrast diffusion, the proposed method has a great improvement in the aspects of subjective visual effect, peak signal-to-noise ratio(PSNR) and mean-square error(MSE). Noise is suppressed more effectively and the minutiae information is preserved better in the image. 展开更多
关键词 welding defect detection noise reduction nonsubsampled contourlet transform total variation model Catte_PM model
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Anisotropic nonlinear diffusion approach to single image resolution enhancement 被引量:2
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作者 XIE Mei-hua- and WANG Zheng-ming Department of Mathematics,Science College,National University of Defense Technology,Changsha,Hunan 410073,China 《Optoelectronics Letters》 EI 2005年第2期144-147,共4页
In many image resolution enhancement applications,the blurring process of the imaging system is unknown.This paper discusses the problem of single image blind resolution enhancement without estimating the point spread... In many image resolution enhancement applications,the blurring process of the imaging system is unknown.This paper discusses the problem of single image blind resolution enhancement without estimating the point spread function(PSF).A regularization model is constructed for image enhancement based on the prior informaton of image error and image gray value,which does not need any prior information of PSF.Moreover,through the solution of Euler equations,an anisotropic nonlinear diffusion equation are obtained,which can avoid the high computational cost of regularization model.Furthermore,in order to get sub-pixel superresolved image,the regularization model for image enhancement is extended to the enlargement of image,which can enlarge and enhance image at the same time.Last,to get clearer edges,a high frequency enhancement filter is used on the superresolved image.Numerical results show that the new model can get much clearer super-resolution images than traditional methods,and the peak signal to noise ratios (PSNRs) are also higher than traditional methods. 展开更多
关键词 各向 非线性扩散 图象处理 信噪比 图象误差
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Anisotropic fourth-order diffusion regularization for multiframe super-resolution reconstruction
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作者 黄淑英 杨勇 王国宇 《Journal of Central South University》 SCIE EI CAS 2013年第11期3180-3186,共7页
A novel rcgularization-based approach is presented for super-resolution reconstruction in order to achieve good tradeoff between noise removal and edge preservation. The method is developed by using L1 norm as data fi... A novel rcgularization-based approach is presented for super-resolution reconstruction in order to achieve good tradeoff between noise removal and edge preservation. The method is developed by using L1 norm as data fidelity term and anisotropic fourth-order diffusion model as a regularization item to constrain the smoothness of the reconstructed images. To evaluate and prove the performance of the proposed method, series of experiments and comparisons with some existing methods including bi-cubic interpolation method and bilateral total variation method are carried out. Numerical results on synthetic data show that the PSNR improvement of the proposed method is approximately 1.0906 dB on average compared to bilateral total variation method, and the results on real videos indicate that the proposed algorithm is also effective in terms of removing visual artifacts and preserving edges in restored images. 展开更多
关键词 SUPER-RESOLUTION anisotropic fourth-order diffusion bilateral total variation REGULARIZATION
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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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Molecular dynamics simulations investigate the long-range effects on TrpR(tryptophan repressor protein)
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作者 FENG Xianli LIU Jia 《分子科学学报》 CAS 2024年第2期174-181,共8页
Molecular dynamics(MD)simulations and anisotropic thermal diffusion dynamics(ATD)simulations were performed on the wild TrpR and its 75 residue mutant(mTrpR)to investigate TrpR longrange effects.The ATD result shows t... Molecular dynamics(MD)simulations and anisotropic thermal diffusion dynamics(ATD)simulations were performed on the wild TrpR and its 75 residue mutant(mTrpR)to investigate TrpR longrange effects.The ATD result shows that the mTrpR has higher fluctuation than the wild TrpR,and its helix chainⅡF has particular disorder.It is obvious that the 75 residue of wild TrpR and mTrpR affects the protein dynamics flexibilities by the long-range effects.The ATD and MD both confirm that the differences in the size of side-chain and three-dimensional structures of two different 75 residues in the wild TrpR and mTrpR will spread to the entire protein by way of the long-range effects.Long-range effect affects the protein side chain interaction,conformational changes,flexibilities and secondary structures.Further,the ATD result also shows that each 75 residue of the symmetric homodimer has the same effect,and the two 75 residues have a positive correlation in long-range regulating processes.The residues 48,50,71,79 in chainⅠof wild TrpR and residues 45,72,80 in chainⅡof mTrpR play important roles in long-range interaction processes. 展开更多
关键词 MD ATD TrpR long-range effect
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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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Anisotropic mesh generation methods based on ACVT and natural metric for anisotropic elliptic equation 被引量:2
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作者 HUANG YunQing SU YiFan +1 位作者 WEI HuaYi YI NianYu 《Science China Mathematics》 SCIE 2013年第12期2615-2630,共16页
Anisotropic meshes are known to be well-suited for problems which exhibit anisotropic solution features. Defining an appropriate metric tensor and designing an efficient algorithm for anisotropic mesh gen- eration are... Anisotropic meshes are known to be well-suited for problems which exhibit anisotropic solution features. Defining an appropriate metric tensor and designing an efficient algorithm for anisotropic mesh gen- eration are two important aspects of the anisotropic mesh methodology. In this paper, we are concerned with the natural metric tensor for use in anisotropic mesh generation for anisotropic elliptic problems. We provide an algorithm to generate anisotropic meshes under the given metric tensor. We show that the inverse of the anisotropic diffusion matrix of the anisotropic elliptic problem is a natural metric tensor for the anisotropic mesh generation in three aspects: better discrete algebraic systems, more accurate finite element solution and superconvergence on the mesh nodes. Various numerical examples demonstrating the effectiveness are presented. 展开更多
关键词 anisotropic mesh metric tensor SUPERCONVERGENCE anisotropic elliptic equation
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AIG Based Nonlinear Anisotropic Smoothing Strategy for Vector-Valued Images
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作者 张相芬 田蔚风 +1 位作者 陈武凡 叶宏 《Journal of Shanghai Jiaotong university(Science)》 EI 2009年第2期223-228,共6页
The effects of the Rician noise on the calculated tensors are analyzed and an affine invariant gradient (AIG) based nonlinear anisotropic smoothing strategy is presented.The AIG based smoothing strategy is a developme... The effects of the Rician noise on the calculated tensors are analyzed and an affine invariant gradient (AIG) based nonlinear anisotropic smoothing strategy is presented.The AIG based smoothing strategy is a development of the affine invariant nonlinear anisotropic diffusion(AINAD) restoration model,introduced by Guillermo Sapiro,and adopted to restore vector-valued data.To evaluate the efficiency of the presented AINAD model in accounting for the Rician noise introduced into the vector-valued data,the peak-to-peak signal-to-noise ratio(PSNR),signal-to-mean squared error ratio(SMSE) and Beta(parameter that stands for edge preservation) metrics are used.The experiment results acquired from the synthetic and real data prove the good performance of the presented filter. 展开更多
关键词 diffusion tensor imaging (DTI) affine invariant diffusion (AINAD) SMOOTHING Euclidean invariant gradient gradient (AIG) affine invariant nonlinear anisotropic (EIG)
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