双重特征加权模糊支持向量机

针对当前基于特征加权的模糊支持向量机(FSVM)只考虑特征权重对隶属度函数的影响,而没有考虑在样本训练过程中将特征权重应用到核函数计算中的缺陷,提出了同时考虑特征加权对隶属度函数和核函数计算的影响的模糊支持向量机算法——双重特征加权模糊支持向量机(DFW-FSVM).首先,利用信息增益(IG)计算出每个特征的权重;然后...     

A new fuzzy approach for handling class labels in canonical correlation analysis

Canonical correlation analysis (CCA) can extract more discriminative features by utilizing class labels, especially the ones that can reflect the sample distribution appropriately. In this paper, a new fuzzy approach for handling class labels in the form of fuzzy membership degrees is proposed. We elaborately design a novel fuzzy membership function to represent the distribution of image samples. These fuzzy class labels promote the classification performances of CCA and kernel CCA (KCCA) through incorporating distribution information into the process of feature extraction. Comprehensive experimental results on face recognition demonstrate the effectiveness and feasibility of the proposed method.     

核空间广义均衡模糊C-均值聚类算法

目的 针对现有广义均衡模糊C-均值聚类不收敛问题,提出一种改进广义均衡模糊聚类新算法,并将其推广至再生希尔伯特核空间以便提高该类算法的普适性。方法 在现有广义均衡模糊C-均值聚类目标函数的基础上,利用Schweizer T范数极限表达式的性质构造了新的广义均衡模糊C-均值聚类最优化目标函数,然后采用拉格朗日乘子法获取其迭代求解所对应的隶属度和聚类中心表达式,同时对其聚类中心迭代表达式进行修改并得到一类聚类性能显著改善的修正聚类算法;最后利用非线性函数将数据样本映射至高维特征空间获得核空间广义均衡模糊聚类算法。结果 对Iris标准文本数据聚类和灰度图像分割测试表明,提出的改进广义均衡模模糊聚类新算法及其修正算法具有良好的分类性能,核空间广义均衡模糊聚类算法对比现有融入类间距离的改进模糊C-均值聚类(FCS)算法和改进再生核空间的模糊局部C-均值聚类(KFLICM)算法能将图像分割的误分率降低10%30%。结论 本文算法克服了现有广义均衡模糊C-均值聚类算法的缺陷,同时改善了聚类性能,适合复杂数据聚类分析的需要。     

基于核函数的SOM网络流量分类方法

由于网络流量数据高度非线性,传统的自组织映射(self-organizing maps,SOM)网络对此分类的鲁棒性和可靠性较差,提出了一种基于核函数的SOM(kernel SOM,KSOM)网络流量分类方法。该方法用核函数代替原始数据在特征空间中映射值的内积,使输入空间中复杂的流量样本结构在特征空间中得到简化,实现对有多个统计特征属性的网络流量在应用层的分类。实验结果表明,KSOM能识别新应用类型的流量,较传统的SOM更适合对网络流量进行分类,其分类准确率高于NB方法。     

Fuzzy discriminant analysis with kernel methods

A novel fuzzy nonlinear classifier, called kernel fuzzy discriminant analysis (KFDA), is proposed to deal with linear non-separable problem. With kernel methods KFDA can perform efficient classification in kernel feature space. Through some nonlinear mapping the input data can be mapped implicitly into a high-dimensional kernel feature space where nonlinear pattern now appears linear. Different from fuzzy discriminant analysis (FDA) which is based on Euclidean distance, KFDA uses kernel-induced distance. Theoretical analysis and experimental results show that the proposed classifier compares favorably with FDA.     

The support vector machine based on intuitionistic fuzzy number and kernel function

Fuzzy support vector machine applied a degree of membership to each training point and reformulated the traditional support vector machines, which reduced the effects of noises and outliers for classification. However, the degree of membership only considered the distance from samples to the class center in the sample space, while neglected the situation of samples in the feature space and easily mistook the edge support vectors as noises. To deal with the aforementioned problems, the support vector machine based on intuitionistic fuzzy number and kernel function is proposed. In the high-dimensional feature space, each training point is assigned with a corresponding intuitionistic fuzzy number by the use of kernel function. Then, a new score function of the intuitionistic fuzzy numbers is introduced to measure the contribution of each training point. In the end, the new support vector machine is constructed according to the score value of each training point. The simulation results demonstrate the effectiveness and superiority of the proposed method.     

一种基于混合核函数的SOM网络流量分类方法

由于传统的自组织映射SOM方法对高维、非线性的网络流量数据的分类性能效果不佳,本文引入核方法,提出一种基于混合核函数的SOM(MIX-KSOM)网络流量分类方法。该方法结合了全局性和局部性核函数的优点,采用径向基函数和多项式函数线性组合构成的混合核函数代替内积作为距离度量,使输入空间中复杂的流量样本在特征空间得以简化。实验结果表明,采用MIX-KSOM方法能较好地对网络流量进行分类,较传统的SOM、采用单一核函数的SOM(KSOM)分类方法性能更好,分类准确率也高于NB方法。     

基于空谱特征的核极端学习机高光谱遥感图像分类算法

近年来,局部二值模式(Local Binary Patterns,LBP)由于其在空间特征提取方面具有显著的优势被应用于高光谱遥感图像分类中,该算法在空间特征提取上虽减少类内方差,却忽视了用于区分不同地物类别的光谱特征。为避免在图像分类过程中提取单一特征导致特征提取不充分、分类效果不理想的问题,通过将空间特征和光谱特征进行矢量堆叠得到新的空谱特征向量。再将新的空谱特征向量引入到核极端学习机中,提出一种基于空谱特征的核极端学习机高光谱遥感图像分类算法(Space Spectrum feature Kernel Extreme Learning Machine,SS-KELM)。为验证所提算法的有效性,将使用两个高光谱图像数据集进行实验。实验结果表明所提SS-KELM算法的分类性能优于目前较为常见的传统分类算法。     

小波核局部Fisher判别分析的高光谱遥感影像特征提取

为了提高高光谱遥感影像的分类精度,充分利用影像的光谱和局部信息,文中提出小波核局部Fisher判别分析的高光谱遥感影像特征提取方法.通过小波核函数将数据集从低维原始空间映射至高维特征空间,考虑到数据的局部信息,利用加权矩阵计算散度矩阵,对局部Fisher判别准则函数求解最优特征矩阵,使不同类别的样本在高维特征空间中的可分离性更佳.在2个公开高光谱数据集上的实验表明,文中方法的总体分类精度和Kappa系数都有所提高.     

基于特征距离的阈值法及其在眼科图象分割中的应用

医学图象的识别与分析能够为临床提供定量比的诊断依据,而图象分割是其中最关键的一步。为提高医学图象侵分割效果,提出了一种基于特征距离的阈值分割算法,并将其与颜色特征分类相结合,来对眼科裂隙灯生物显微镜图象上的角膜充血区进行分割,分割结果可用于角膜充血区的定量体分析,另外,该算法中的样本典型值是通过一种三维直方图分块算法来确定的,实验结果表明,该算法可以有效地分割出角膜充血,其分割效果优于欧氏距离阈值法,且分析数据的精度能够达到临床诊断的要求。     

Feature extraction and dimensionality reduction by genetic programming based on the Fisher criterion

Abstract: Feature extraction helps to maximize the useful information within a feature vector, by reducing the dimensionality and making the classification effective and simple. In this paper, a novel feature extraction method is proposed: genetic programming (GP) is used to discover features, while the Fisher criterion is employed to assign fitness values. This produces non‐linear features for both two‐class and multiclass recognition, reflecting the discriminating information between classes. Compared with other GP‐based methods which need to generate c discriminant functions for solving c‐class (c>2) pattern recognition problems, only one single feature, obtained by a single GP run, appears to be highly satisfactory in this approach. The proposed method is experimentally compared with some non‐linear feature extraction methods, such as kernel generalized discriminant analysis and kernel principal component analysis. Results demonstrate the capability of the proposed approach to transform information from the high‐dimensional feature space into a single‐dimensional space by automatically discovering the relationships between data, producing improved performance.     

一种新的核线性鉴别分析算法及其在人脸识别上的应用

基于核策略的核Fisher鉴别分析（KFD）算法已成为非线性特征抽取的最有效方法之一。但是先前的基于核Fisher鉴别分析算法的特征抽取过程都是基于2值分类问题而言的。如何从重叠（离群）样本中抽取有效的分类特征没有得到有效的解决。本文在结合模糊集理论的基础上，利用模糊隶属度函数的概念，在特征提取过程中融入了样本的分布信息，提出了一种新的核Fisher鉴别分析方法——模糊核鉴别分析算法。在ORL人脸数据库上的实验结果验证了该算法的有效性。     

基于核函数与马氏距离的FCM图像分割算法

针对模糊聚类算法邻域信息与空间信息利用率低易受噪声影响的问题,提出一种结合核函数与马氏距离的FCM算法,即FCMKM算法。首先,将图像像素点由低维空间通过核函数非线性映射到高维空间;然后,利用马氏距离替换原有的欧氏距离作为高维空间距离量度;最后,利用改进后的算法对图像进行分割。为验证FCMKM算法的性能,选取Bezdek划分系数、Xie-Beni系数、重构错误率、运行时间、迭代次数五个评测指标作为对比实验的评价标准。实验结果表明,与传统FCM算法、基于核函数的FCM算法、基于马氏距离的FCM算法相比,FCMKM算法能有效地提高模糊聚类算法的抗噪性。     

基于测地距离的KPCA人脸识别

针对人脸检测数据集中的信息均为高维特征向量且人脸识别易受表情变化影响等问题,本文提出一种基于测地距离的KPCA人脸识别方法,该方法利用非线性方法提取主成分。先采用KPCA方法把人脸数据映射到高维空间,进而在高维空间中提取人脸的主成分,其中核函数为多项式核函数;然后引入测地距离替换原来的欧氏距离进行相似度量,其能更准确地测量出两像素点间的实际距离,使得人脸识别率受表情变化影响小。该方法不但可以实现降维,而且还能达到有效提取特征的目的。在ORL人脸库上的实验结果表明,该方法的识别率明显优于PCA、KPCA等方法的识别率。     

超光谱遥感图像有监督LPP特征提取研究

在局部保留投影(LPP)特征提取算法的基础上,利用样本标签信息提出了一种有监督的局部保留投影算法(SPLPP),该算法的邻接图的权值不仅考虑了LPP算法中的相似性权值,而且加入了监督类的相关权值。SPLPP算法主要步骤是先用PCA去除高维超光谱遥感图像的冗余信息,再把监督机制引入到LPP中,实现图像的特征提取,将高维超光谱遥感图像投影到低维空间中,利于分类。应用SPLPP算法对高维的遥感原始超光谱图像进行特征提取后,利用支持向量机(SVM)和最近邻分类器(KNN)对降维后的遥感图像数据进行分类;并与PCA、LPP、LDA等特征提取算法进行了比较实验。实验表明:结合了LPP局部信息保留能力和全域标签信息的SPLPP算法,有更好的局部信息保留能力和类判别能力,使分类器分类精度更高,分类效果更好。     

An enhanced Support Vector Machine classification framework by using Euclidean distance function for text document categorization

This paper presents the implementation of a new text document classification framework that uses the Support Vector Machine (SVM) approach in the training phase and the Euclidean distance function in the classification phase, coined as Euclidean-SVM. The SVM constructs a classifier by generating a decision surface, namely the optimal separating hyper-plane, to partition different categories of data points in the vector space. The concept of the optimal separating hyper-plane can be generalized for the non-linearly separable cases by introducing kernel functions to map the data points from the input space into a high dimensional feature space so that they could be separated by a linear hyper-plane. This characteristic causes the implementation of different kernel functions to have a high impact on the classification accuracy of the SVM. Other than the kernel functions, the value of soft margin parameter, C is another critical component in determining the performance of the SVM classifier. Hence, one of the critical problems of the conventional SVM classification framework is the necessity of determining the appropriate kernel function and the appropriate value of parameter C for different datasets of varying characteristics, in order to guarantee high accuracy of the classifier. In this paper, we introduce a distance measurement technique, using the Euclidean distance function to replace the optimal separating hyper-plane as the classification decision making function in the SVM. In our approach, the support vectors for each category are identified from the training data points during training phase using the SVM. In the classification phase, when a new data point is mapped into the original vector space, the average distances between the new data point and the support vectors from different categories are measured using the Euclidean distance function. The classification decision is made based on the category of support vectors which has the lowest average distance with the new data point, and this makes the classification decision irrespective of the efficacy of hyper-plane formed by applying the particular kernel function and soft margin parameter. We tested our proposed framework using several text datasets. The experimental results show that this approach makes the accuracy of the Euclidean-SVM text classifier to have a low impact on the implementation of kernel functions and soft margin parameter C.     

基于核最小噪声分离变换的高光谱遥感影像特征提取研究

高光谱遥感影像具有高维非线性的特点,线性特征提取方法容易造成信息丢失和失真。在最小噪声分离变换(MNF)线性特征提取算法的基础上,引入核方法,提出核最小噪声分离变换(KMNF)高光谱遥感影像非线性特征提取方法。KMNF通过核函数,将样本映射到高维特征空间,在特征空间中运算线性MNF,实现原始空间中的非线性KMNF算法。进行基于KMNF的高光谱影像特征提取实验,分析样本个数对KMNF特征提取的效果,发现样本数量对KMNF特征提取的结果影响很小,较少的样本数即可达到较多样本时特征提取的效果。对比KMNF与MNF特征提取的效果,分析它们降维的效率与保留的信息量,发现KMNF总体降维效率与MNF相当,且体现出高光谱图像的非线性特征;在KMNF和MNF特征提取的基础上,利用SVM进行高光谱图像分类,KMNF+SVM的分类精度优于MNF+SVM。     

隐空间中参数化直接鉴别分析及其应用

提出了一种新的非线性特征抽取方法——隐空间中参数化直接鉴别分析。其主要思想是利用一核函数将原始输入空间非线性变换到隐空间,针对在该隐空间中类内散布矩阵总是奇异等问题,利用参数化直接鉴别分析进行特征抽取。与现有的核特征抽取方法不同的是,该方法不需要核函数满足Mercer 定理,从而增加了核函数的选择范围。更为重要的是,由于在隐空间中采用了参数化直接鉴别分析,不仅保留了参数化直接鉴别分析的优点,而且有效地抽取了样本的非线性特征;在该方法中提出了一个更为合理的加权系数矩阵,提高了分类性能。在FERET人脸数据库子库上的实验结果验证了该方法的有效性。     

一种嵌入局部信息的快速KFCM聚类分割算法

针对核空间模糊局部C-均值聚类分割算法时间复杂性过大而不适合实时场合图像分割需要的问题,提出了一种核空间局部模糊C-均值聚类分割的快速算法。利用像素与其邻域像素之间的空间距离信息和灰度方差信息构造一种加权共生矩阵;将图像像素的一维直方图以及像素与邻域像素之间的二维共生直方图相结合构造了一种新的核空间模糊C-均值聚类分割目标函数,并对其推导获得隶属度和聚类中心迭代表达式;将图像像素采用该算法聚类所得隶属度进行邻域滤波处理,以便改善该算法的抗噪性能。实验结果表明,该分割算法相比核空间局部模糊C-均值聚类分割更有利于实时场合和大幅面图像分割的需要。     

Strong fuzzy c-means in medical image data analysis

This paper presents a robust fuzzy c-means (FCM) for an automatic effective segmentation of breast and brain magnetic resonance images (MRI). This paper obtains novel objective functions for proposed robust fuzzy c-means by replacing original Euclidean distance with properties of kernel function on feature space and using Tsallis entropy. By minimizing the proposed effective objective functions, this paper gets membership partition matrices and equations for successive prototypes. In order to reduce the computational complexity and running time, center initialization algorithm is introduced for initializing the initial cluster center. The initial experimental works have done on synthetic image and benchmark dataset to investigate the effectiveness of proposed, and then the proposed method has been implemented to differentiate the different region of real breast and brain magnetic resonance images. In order to identify the validity of proposed fuzzy c-means methods, segmentation accuracy is computed by using silhouette method. The experimental results show that the proposed method is more capable in segmentation of medical images than existed methods.