计算机视觉中标记点匹配算法

计算机视觉测量中,多幅图像标记点自动匹配是实现测量自动化的重要环节。本文提出了标记点的自动匹配方法。该方法首先采用编码标记点得到初始匹配集,根据相似性将解码错误的剔除得到良好的匹配集。然后使用极线约束、反投影残差、图像绝对距离比约束实现非编码标记点的正确匹配。实验表明该方法在一般拍摄条件下,非编码标记点的匹配正确率可高达97%。     

基于SIFT特征点改进搜索算法的图像匹配技术研究

本文研究一种改进的近邻搜索算法的图像匹配技术。本文采用基于特征的图像匹配方法,利用SIFT算法提取特征点。在特征点匹配的过程中,为提高搜索样本特征点的最近邻和次近邻特征点的速度,本文采用一种基于二叉检索树算法改进的近邻搜索算法,该算法用最近邻与次近邻比值来进行特征点的匹配。用MATLAB语言实现该算法并运用到图像特征匹配中,实验证明优于原算法并具有较高实时性。     

基于特征点图像匹配的面部识别方法

面部识别被认为是生物特征识别领域甚至人工智能领域最困难的研究课题之一,如何进行好面部识别工作对于生活、生产都有着十分重要的意义。本文提出一种基于特征点提取的面部识别方法,在得到已知图像和待识别图像以后,先对其进行边缘提取和点特征提取,然后基于提取的特征点进行灰度模板匹配,通过图像匹配的结果对图像进行识别。     

法向量夹角的点云特征线提取算法研究

文章提出一种基于法向量夹角的点云特征线提取算法，该算法过程主要分为特征点提取和特征点连接两个阶段。在基于法向量夹角的特征点提取的过程中，通过构建最小生成树来实现法向量重定向，一定程度上提高了传统法向量提取特征点的准确性，随后对初选特征点进行细化和删减，得到点云数据的特征点集。在特征点连接阶段通过建立特征点的最小生成树以及相应的最小生成树裁剪算法构建特征曲线。实验证明，该算法原理简单，能很好地提取点云模型尖锐特征与细节特征，是一种有效的三维点云特征线提取算法。     

基于harris算子的影像特征匹配

针对航空影像,采用harris算子提取影像特征点,以提取出的特征点为待匹配点进行灰度相关匹配。实验表明,harris算子提取的特征点效果良好且均匀分布,基于harris算子的特征匹配具有较高的成功率,能够实现高精度影像自动匹配。     

基于点相互关系特征点匹配算法的标志图匹配

图像中标志图匹配问题实际上是图像处理领域的一个分支,多用于图像分析处理等任务的过程中,是图像处理领域的一个研究热点。鉴于当前大多数的特征点匹配算法只考虑了样本特征点与目标特征点的关系,本文首先对特征提取后的特征点集进行预处理,并将同一特征点集中特征点间的相互关系作为约束引入到匹配中,建立了一个匹配代价函数。并将该匹配代价函数转化为一个线性问题,求解该线性问题以达到特征点匹配目的。     

一种基于斜率变化间接提取轮廓特征点的算法

提出了一种基于斜率变化间接提取轮廓特征点的新算法,该算法通过对轮廓点序列在X、Y方向进行分解以简化运算,减少噪声干扰。给出了算法的实现过程。理论和试验结果表明,该算法对于特征点的提取不仅计算量小,易于实现,且对特征点的定位也比较准确。     

基于改进Harris算法与改进的SIFT算法相结合的图像匹配方法

文章针对图像自相似或具有对称性SIFT匹配稳定性不高的问题,提出了改进的SIFT算法与改进的Harris算法相结合的图像匹配方法,对SIFT特征在纹理丰富的图像中提取较多的伪点和不稳定的点而影响图像匹配问题,提出了一种基于Harris阈值准则的局部不变特征图像匹配算法。该算法在提取SIFT不变特征的基础上,利用Harris闽值准则对所提取到的不变特征进行选择,剔除了图像区域中大量可区分性较差的特征点,从而得到了相对稳定和可区分性较好的特征点。其次,结合不变特征矢量与图转换匹配(GTM)的方法对提取到的稳定特征点进行了精确匹配。实验对比结果表明,用取得稳定的特征点,进而结合一种好的匹配策略,能够更加增强图像匹配的高效性和鲁棒性。     

指纹细节特征提取算法的优化研究

指纹细节特征提取是指纹识别的前提。提出了一种改进的基于细化图像的指纹细节特征提取方法,该方法首先在二值细化图像上提取细节点,对于各种原因产生的伪特征,根据其拓扑结构,结合二值形态学操作,分别采用不同的后处理规则予以剔除,然后将后处理得到的细节点集放到原始指纹灰度图像上去检验以进一步提高细节点的准确性,最后在FVC2002DB1上的对比实验验证了该方法的有效性。     

一种基于SIFT和点集不变性的图像匹配算法

图像中的特征点可以用来匹配图像.本文给出了一个基于SIFT特征点集之间距离的图像匹配算法.首先提取出图像中的所有SIFT特征点,然后根据奇异值分解再选出特征点集,根据点集不变性计算出距离,最后根据距离值匹配图像,实验结果显示,该算法具有可行性.     

基于改进的LBP特征和随机森林相结合的人脸关键点检测方法研究

提出了一种人脸关键点检测方法,该方法用了少量的正面图像,不用归一化人脸图像,而传统的人脸关键点检测方法需要对图像进行严格预处理。随机森林是一种分类器融合算法,可以很好地解决多类分类问题,虽然LBP特征简单,但其可以包含大量的纹理信息。利用改进的LBP特征与随机森林相结合,构成一种对人脸关键点检测的方法。通过高斯平滑图像的LBP特征的提取,对每个点生成特征,计算出有用的特征作为正例,并且与反例集合变为训练集。通过随机森林分类器进行分类,误差率较低,仅在10％左右。     

Using cluster validation criterion to identify optimal feature subset and cluster number for document clustering

This paper presents a cluster validation based document clustering algorithm, which is capable of identifying an important feature subset and the intrinsic value of model order (cluster number). The important feature subset is selected by optimizing a cluster validity criterion subject to some constraint. For achieving model order identification capability, this feature selection procedure is conducted for each possible value of cluster number. The feature subset and the cluster number which maximize the cluster validity criterion are chosen as our answer. We have evaluated our algorithm using several datasets from the 20Newsgroup corpus. Experimental results show that our algorithm can find the important feature subset, estimate the cluster number and achieve higher micro-averaged precision than previous document clustering algorithms which require the value of cluster number to be provided.     

基于合作博弈的供应链伙伴绩效灰色综合评价方法

针对供应链伙伴绩效评价的特点,以灰色理论和博弈论为基础,提出并论证了一个基于Shapley值的灰色综合绩效评价方法。该方法考虑了伙伴各方在群体决策时的合作博弈过程,以Shapley值代表其影响力;同时,运用灰色理论将评价者的分散信息转换为描述不同灰类程度的权向量,减少了信息的丢失,从而提高了评价结果的有效性;最后,通过算例说明了该方法的应用。     

基于单张正面人脸图像的三维人脸自动建模系统实现

研究了一种基于正面人脸照片的真实感三维人脸自动重建方法,并运用计算机视觉图OpenCV和图形开发库OpenGL ,在VC＋＋6．0环境下开发了三维人脸自动建模系统。该系统对输入的人脸照片首先进行人脸检测,在检测到的区域进行人脸关键特征提取,并根据检测到的特征点的几何信息对CANDIDE-3模型进行整体和局部调整,得到个性化的三维几何人脸,最后从人脸图像上获取面部纹理信息并得到真实感的三维人脸。     

基于颜色与投影特征的车牌定位

车牌定位是车牌识别系统的关键技术,定位的准确与否直接影响车牌识别的结果。本文根据车牌的颜色特征和投影特征提出了一种综合颜色特征和投影特征相结合的定位方法,算法分为粗定位和精确定位。该方法较单一特征的定位方法有较好的通用性,可适应于不同背景、不同光照下的汽车图像,能够确定出车牌区域,准确率得到了较大提高。     

Supervised Hebb rule based feature selection for text classification

Text documents usually contain high dimensional non-discriminative (irrelevant and noisy) terms which lead to steep computational costs and poor learning performance of text classification. One of the effective solutions for this problem is feature selection which aims to identify discriminative terms from text data. This paper proposes a method termed “Hebb rule based feature selection (HRFS)”. HRFS is based on supervised Hebb rule and assumes that terms and classes are neurons and select terms under the assumption that a term is discriminative if it keeps “exciting” the corresponding classes. This assumption can be explained as “a term is highly correlated with a class if it is able to keep “exciting” the class according to the original Hebb postulate. Six benchmarking datasets are used to compare HRFS with other seven feature selection methods. Experimental results indicate that HRFS is effective to achieve better performance than the compared methods. HRFS can identify discriminative terms in the view of synapse between neurons. Moreover, HRFS is also efficient because it can be described in the view of matrix operation to decrease complexity of feature selection.     

Capturing the form of feature interactions in black-box models

Detecting feature interactions is an important post-hoc method to explain black-box models. The literature on feature interactions mainly focus on detecting their existence and calculating their strength. Little attention has been given to the form how the features interact. In this paper, we propose a novel method to capture the form of feature interactions. First, the feature interaction sets in black-box models are detected by the high dimensional model representation-based method. Second, the pairwise separability of the detected feature interactions is determined by a novel model which is verified theoretically. Third, the set separability of the feature interactions is inferred based on pairwise separability. Fourth, the interaction form of each feature in product separable sets is explored. The proposed method not only provides detailed information about the internal structure of black-box models but also improves the performance of linear models by incorporating the appropriate feature interactions. The experimental results show that the accuracy of recognizing product separability in synthetic models is 100%. Experiments on three regression and three classification tasks demonstrate that the proposed method can capture the product separable form of feature interactions effectively and improve the prediction accuracy greatly.     

基于神经网络的数字识别技术研究

将图像的像素特征与矩特征结合,构建了神经网络分类器,利用提取的特征向量对分类器进行了训练和测试。将图像二值化,并归一化为16＊16大小,提取了其每个像素点的0、1特征共16＊16—256维,图像的网格特征13维,及Hu矩特征7维,一共276维特征。建立了BP神经网络分类器,分别使用最速下降BP算法、动量BP算法、学习率可变BP算法对BP神经网络分类器进行了训练,得出了在相同条件下学习率可变BP算法训练时间短,收敛快的结论。建立了PNN神经网络分类器,与BP神经网络分类器性能进行比较,实验结果表明,PNN神经网络分类器性能更好。     

基于向量空间模型的特征抽取技术分析

特征降维是基于向量空间模型(VSM)文本分类的关键技术之一,特征抽取是特征降维的主要方法。本文主要分析了几种常用的特征抽取方法,并给出了它们的实现步骤。     

Information gain and divergence-based feature selection for machine learning-based text categorization

Most previous works of feature selection emphasized only the reduction of high dimensionality of the feature space. But in cases where many features are highly redundant with each other, we must utilize other means, for example, more complex dependence models such as Bayesian network classifiers. In this paper, we introduce a new information gain and divergence-based feature selection method for statistical machine learning-based text categorization without relying on more complex dependence models. Our feature selection method strives to reduce redundancy between features while maintaining information gain in selecting appropriate features for text categorization. Empirical results are given on a number of dataset, showing that our feature selection method is more effective than Koller and Sahami’s method [Koller, D., & Sahami, M. (1996). Toward optimal feature selection. In Proceedings of ICML-96, 13th international conference on machine learning], which is one of greedy feature selection methods, and conventional information gain which is commonly used in feature selection for text categorization. Moreover, our feature selection method sometimes produces more improvements of conventional machine learning algorithms over support vector machines which are known to give the best classification accuracy.