一种高效的图像数据库检索方法

对于大型图像库,如何高效地检索出相似图像是图像检索系统的一大挑战。提出了一种改进的K-均值聚类算法建立分层结构的索引,再利用A*树算法和三角不等式原则及N近邻方法对索引库快速高效地搜索,达到对图像库快速高效检索相似图像的目的。实验在Corel图像库上进行,实验结果表明该方法以对数时间复杂度实现基于内容的高效检索。     

一种有效的支持海量图像数据库QBE查询的聚类索引算法

对海量图像数据进行基于内容的查询与检索有赖于高效的索引和检索机制。因此,如何将海量图像数据进行合理的分类,人而建立相应的索引机制就成为了一个亟待解决的问题。本文提出了一种有效的支持海量图像数据库QBE查询的聚类索引算法。实验在1万多幅的图像数据库上进行了反复测试,结果表明该算法可以极大地提高检索效率。     

一种基于独立分类特征的指纹多级分类算法

为了提高基于大容量指纹库的自动指纹识别系统的检索效率,提出一种基于独立分类特征的指纹多级分类算法。依据评测指标对输入指纹图像进行质量评估,若指纹质量不合格,则提醒用户重新输入;若指纹质量合格,则分别利用指纹图像的纹型类别、奇异点间脊线数、中心区域脊线平均频率3个相互独立的分类特征实现多级分类,从而逐级减小检索空间。实验结果表明,该分类算法检索效率高、鲁棒性强,为大容量指纹库提供了一种快速有效的索引机制,具有很强的实用性。     

改进k-means聚类算法在图像检索中的应用研究

为了从大规模图像数据库中快速而准确地检索到所需图像,提出了一种结合图像特征索引库和平均面积直方图的方法。通过图像特征索引库减少对图像数据库的访问次数和访问数据量,实现对图像的快速检索。使用平均面积直方图方法,增强算法区分空间差异的能力,使得检索结果与人的视觉感受更加吻合。实验结果亦表明,该方法提高了图像检索的速度和精度。     

图像数据库分类的自组织技术

本文采用 Kohoenmap自组织神经网络技术 ,提出一种依据检索特征对图像数据库进行预分类的方法 .在文中利用这种预分类实现按类别浏览图像数据库 (image browsing by category)的功能 ,提出一种层次化的类 SS- tree的二分索引结构 .实现建立在预分类基础上的示例查询 .这种查询方法与穷搜索方法相比 ,具有更高的检索效率 ,检索次数随着库规模的增加不会显著增多 .基于图像库的实验验证了分类算法和检索算法的有效性     

高效聚类索引表图像检索

提出了一种基于主颜色、聚类索引表的彩色图像检索算法。应用MPEG-7视觉内容描述对彩色图像进行量化处理,选取图像的主颜色及其所占百分率作为颜色特征,根据主颜色组合建立聚类索引数据库。利用上述主颜色特征计算图像间的相似度,利用聚类索引表对图像进行聚类和快速检索。实验表明,该算法能够准确和高效地检索出用户所需的彩色图像,具有较快的检索速度。     

利用差分矩阵进行基于内容的图像检索

随着大容量图像数据库的广泛应用,基于内容的图像检索(CBIR)技术成为对其进行管理和检索的有效手段。文中提出了一种基于灰度变化进行基于内容的图像检索的方法,利用差分概念提取出图像的差分矩阵,再从中提取特征进行度量。给出了对自然图像库检索的实验结果,实验表明,采用该方法比空间颜色直方图与共生矩阵等方法能取得更好的检索效果。与颜色空间直方图和灰度共生矩阵的比较实验证明差分矩阵的方法在速度和结果上都有比较好的效果。     

基于内容的图像检索技术研究

随着数字图像在多媒体领域的广泛应用,对基于内容的图像检索技术的需求也不断增加.基于内容的图像检索技术总体上可以分为两部分:图像特征提取、图像特征的索引与匹配.图像特征提取主要解决如何在数学上有效地描述一幅图像.文中分别介绍了颜色、形状和纹理特征提取算法近年来的研究成果.图像特征索引与匹配,主要解决如何根据特征描述判断图像间的相似程度,并准确、快速列出图像库中与检索图像相似的图像,分别介绍了相似度测量方法、聚类与分类技术、相关反馈技术三类技术的主要研究成果.最后对基于内容的图像检索技术的研究难点进行了讨论,对未来可能的研究方向进行了展望.     

基于聚类的图像视觉内容检索和索引

图像是一种典型的可以大量获取的多媒体数据，对它们进行内容管理具有实际意义，描述在BOIC系统中提出并实现的基于聚类机制的图像视觉内容检索和索引方法．首先给出以视觉特征、空间结构、语义注释等来表示图像内容的模型；然后给出基于该模型的三个检索算法，包括基于视觉感知的颜色检索算法、轮廓检索算法、主色调扩展检索算法；最后给出采用集簇算法时媒体数据进行聚类的索引机制．它建立聚类索引表来缩小查询范围，从而提高了检索效率。     

利用差分矩阵进行基于内容的图像检索

随着大容量图像数据库的广泛应用,基于内容的图像检索(CBIR)技术成为对其进行管理和检索的有效手段.文中提出了一种基于灰度变化进行基于内容的图像检索的方法,利用差分概念提取出图像的差分矩阵,再从中提取特征进行度量.给出了对自然图像库检索的实验结果,实验表明,采用该方法比空间颜色直方图与共生矩阵等方法能取得更好的检索效果.与颜色空间直方图和灰度共生矩阵的比较实验证明差分矩阵的方法在速度和结果上都有比较好的效果.     

Structural feature indexing for retrieval of partially visible shapes

Efficient and robust information retrieval from large image databases is an essential functionality for the reuse, manipulation, and editing of multimedia documents. Structural feature indexing is a potential approach to efficient shape retrieval from large image databases, but the indexing is sensitive to noise, scales of observation, and local shape deformations. It has now been confirmed that efficiency of classification and robustness against noise and local shape transformations can be improved by the feature indexing approach incorporating shape feature generation techniques (Nishida, Comput. Vision Image Understanding 73 (1) (1999) 121-136). In this paper, based on this approach, an efficient, robust method is presented for retrieval of model shapes that have parts similar to the query shape presented to the image database. The effectiveness is confirmed by experimental trials with a large database of boundary contours obtained from real images, and is validated by systematically designed experiments with a large number of synthetic data.     

SEP6200的嵌入式指纹检索系统设计

在具有大容量数据库的指纹识别系统中,使用指纹检索算法能够有效缩小指纹的对比范围,提高系统的识别率。本文在对传统自动指纹识别系统研究的基础上,提出了一种嵌入式指纹检索系统的设计方案。文章首先阐述了基于指纹综合特征的指纹索引与检索算法的设计思路;然后针对算法软件,设计了基于SEP6200控制器的嵌入式指纹检索应用平台;最后通过实验测试,证明系统的性能与效率满足应用需求。     

The study of indexing techniques on object oriented databases

An object-oriented database (OODB) has been becoming more important in recent years. It can deal with a large amount of complex objects and relationships that relational database (RDB) systems cannot handle well. However, the retrieval and update performance of an OODB depends on indexing techniques. In this paper, we study the indexing techniques on OODBs, based on an inheritance hierarchy and an aggregation hierarchy. Given the access probability and the size of each class, we propose a cost function to evaluate the gain of building an index on an inheritance hierarchy. For an aggregation hierarchy, we use a path-catenation technique to evaluate how to build index files on classes. Through some experiments, we found our methods have better retrieval performance than most ones proposed before.     

Indexing chromatic and achromatic patterns for content-based colour image retrieval

In this paper, we present a method to represent achromatic and chromatic image signals independently for content-based image indexing and retrieval for image database applications. Starting from an opponent colour representation, human colour vision theories and modern digital signal processing technologies are applied to develop a compact and computationally efficient visual appearance model for coloured image patterns. We use the model to compute the statistics of achromatic and chromatic spatial patterns of colour images for indexing and content-based retrieval. Two types of colour images databases, one colour texture database and another photography colour image database are used to evaluate the performance of the developed method in content-based image indexing and retrieval. Experimental results are presented to show that the new method is superior or competitive to state-of-the-art content-based image indexing and retrieval techniques.     

Inference and retrieval of facial images

Attempts have been made to extend SQL to work with multimedia databases. We are reserved on the representation ability of extended SQL to cope with the richness in content of multimedia data. In this paper we present an example of a multimedia database system, Computer Aided Facial Image Inference and Retrieval system (CAFIIR). The system stores and manages facial images and criminal records, providing necessary functions for crime identification. We would like to demonstrate some core techniques for multimedia database with CAFIIR system. Firstly, CAFIIR is a integrated system. Besides database management, there are image analysis, image composition, image aging, and report generation subsystems, providing means for problem solving. Secondly, the richness of multimedia data urges feature-based database for their management. CAFIIR is feature-based. A indexing mechanism,iconic index, has been proposed for indexing facial images using hierarchical self-organization neural network. The indexing method operates on complex feature measures and provides means for visual navigation. Thirdly, special retrieval methods for facial images have been developed, including visual browsing, similarity retrieval, free text retrieval and fuzzy retrieval.     

A real-time matching system for large fingerprint databases

With the current rapid growth in multimedia technology, there is an imminent need for efficient techniques to search and query large image databases. Because of their unique and peculiar needs, image databases cannot be treated in a similar fashion to other types of digital libraries. The contextual dependencies present in images, and the complex nature of two-dimensional image data make the representation issues more difficult for image databases. An invariant representation of an image is still an open research issue. For these reasons, it is difficult to find a universal content-based retrieval technique. Current approaches based on shape, texture, and color for indexing image databases have met with limited success. Further, these techniques have not been adequately tested in the presence of noise and distortions. A given application domain offers stronger constraints for improving the retrieval performance. Fingerprint databases are characterized by their large size as well as noisy and distorted query images. Distortions are very common in fingerprint images due to elasticity of the skin. In this paper, a method of indexing large fingerprint image databases is presented. The approach integrates a number of domain-specific high-level features such as pattern class and ridge density at higher levels of the search. At the lowest level, it incorporates elastic structural feature-based matching for indexing the database. With a multilevel indexing approach, we have been able to reduce the search space. The search engine has also been implemented on Splash 2-a field programmable gate array (FPGA)-based array processor to obtain near-ASIC level speed of matching. Our approach has been tested on a locally collected test data and on NIST-9, a large fingerprint database available in the public domain     

基于小波分析和Oracle8i的图像数据库系统设计

采用了小波分析以及小波零树编码技术来提取图像特征，在Oracle8i支持图像数据库查询的基础上，综合使用传统的数据库检索技术和初步走向应用的基于内容的查询技术，实验证明这种方法丰富了传统的关系型数据库的功能，并具有良好的检索性能。     

一种面向对象数据库继承层次索引配置方法①

如何平衡面向对象数据库（OODB）索引的检索性能、维护开销、实现复杂度已经成为一个影响OODB性能的关键问题。提出一种OODB继承层次索引配置方法。通过开销模型评估各种索引配置的检索开销、存储开销、更新开销,根据数据库真实使用情况选择最优索引配置。通过实验,验证这种方法的准确性,并且同其他常见索引策略作对比。结果表明该方法可以为OODB提供性能最优的索引方案。