Distinctive Image Features from Scale-Invariant Keypoints

This paper presents a method for extracting distinctive invariant features from images that can be used to perform reliable matching between different views of an object or scene. The features are invariant to image scale and rotation, and are shown to provide robust matching across a substantial range of affine distortion, change in 3D viewpoint, addition of noise, and change in illumination. The features are highly distinctive, in the sense that a single feature can be correctly matched with high probability against a large database of features from many images. This paper also describes an approach to using these features for object recognition. The recognition proceeds by matching individual features to a database of features from known objects using a fast nearest-neighbor algorithm, followed by a Hough transform to identify clusters belonging to a single object, and finally performing verification through least-squares solution for consistent pose parameters. This approach to recognition can robustly identify objects among clutter and occlusion while achieving near real-time performance.  

自动指纹识别中的图像增强和细节匹配算法

对自动指纹识别系统(automated fingerprint identification system,简称AFIS)的两个重要问题——指纹图像增强和细节匹配进行研究,给出了一种基于方向场的指纹图像增强算法,对Anil Jain等人提出的细节匹配算法进行了修正.采用一种新的更简单的方法进行指纹图像的校准,并以一种简单而有效的方式将脊线信息引入匹配过程中,这样做的好处之一是以较低的计算代价有效地解决了匹配中参照点对的选取问题.另外,采用大小可变的限界盒来适应指纹的非线性形变.在FVC2000公布的指纹图像数据库上,按照FVC2000测试标准所做的实验显示,该算法比原算法有较大的改进.  

A Taxonomy and Evaluation of Dense Two-Frame Stereo Correspondence Algorithms

Stereo matching is one of the most active research areas in computer vision. While a large number of algorithms for stereo correspondence have been developed, relatively little work has been done on characterizing their performance. In this paper, we present a taxonomy of dense, two-frame stereo methods. Our taxonomy is designed to assess the different components and design decisions made in individual stereo algorithms. Using this taxonomy, we compare existing stereo methods and present experiments evaluating the performance of many different variants. In order to establish a common software platform and a collection of data sets for easy evaluation, we have designed a stand-alone, flexible C++ implementation that enables the evaluation of individual components and that can easily be extended to include new algorithms. We have also produced several new multi-frame stereo data sets with ground truth and are making both the code and data sets available on the Web. Finally, we include a comparative evaluation of a large set of today's best-performing stereo algorithms.  

A survey of approaches to automatic schema matching

Schema matching is a basic problem in many database application domains, such as data integration, E-business, data warehousing, and semantic query processing. In current implementations, schema matching is typically performed manually, which has significant limitations. On the other hand, previous research papers have proposed many techniques to achieve a partial automation of the match operation for specific application domains. We present a taxonomy that covers many of these existing approaches, and we describe the approaches in some detail. In particular, we distinguish between schema-level and instance-level, element-level and structure-level, and language-based and constraint-based matchers. Based on our classification we review some previous match implementations thereby indicating which part of the solution space they cover. We intend our taxonomy and review of past work to be useful when comparing different approaches to schema matching, when developing a new match algorithm, and when implementing a schema matching component. Received: 5 February 2001 / Accepted: 6 September 2001 Published online: 21 November 2001  

基于多模板匹配的单人脸检测

提出了一种基于多模板匹配的一般环境图象中单人脸的检测方法。首先用双眼模板初步筛选，然后使用具有不同长宽比的多个人脸模板进行检测和定位，最后利用有脸器官的边缘特征进行确认。采用比固定比率压缩输入图象的方法解决不同尺度有脸的检测问题。实验表明这种方法具有较高的速度和检测成功率。  

图像匹配研究进展

图像匹配是计算机视觉和图像处理中一个很重要的研究内容。该文分析了图像匹配中的难点问题及其关键技术，将匹配算法分为四类，综述了具有代表性的传统匹配算法及其改进以及近年来出现的新思路和新方法，探讨了图像匹配中有待进一步研究的问题。  

基于肤色和模板的人脸检测

针对彩色图像提出了一种基于肤色和模板的人脸检测方法,由肤色分割、模板匹配和人工神经网验证3部分组成.首先使用HSI空间的肤色统计模型分割出可能包含人脸的区域,然后使用平均脸模板匹配和人工神经网验证的方法在这些区域中搜索人脸.该方法将彩色图像的肤色信息和灰度图像的模板匹配及人工神经网分类模型综合起来,既极大地提高了速度,又具有较强的鲁棒性.实验结果表明,该算法是快速而有效的.  

基于刻面描述的构件检索

随着软件复用实践的深入和软件构件库规模的扩大,对软件构件的表示与检索的研究正受到越来越多的重视.针对基于刻面描述的软件构件,结合模式分析中的树匹配思想,根据构件刻面描述的特点,提出了一种基于树包含(tree inclusion)的构件检索方法,并进行了理论上的分析与实验上的检验.实验结果证明了它的可行性与有效性.  

灰度图像匹配的快速算法

提出了一种基于小波变换和投影特征的图像匹配的快速算法．先在若干级小波变换的低频图上利用投影特征、序贯相似性算法等手段得到一个可能的匹配点的集合，然后对该集合上的点在原图上作匹配运算，得出准确匹配位置．该算法大大提高了运算速度，同时又保持了匹配的精度，可以满足实时性的要求。