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51.
A method is described to extract an index from a binary character image for database storage and retrieval. The index is hierarchical in nature, and different parts can retrieve character image clusters of different sizes. A hierarchy of Kohonen neural networks is used to generate the clusters on which the indexing method is based. The application is the identification of the font from a sample of printed characters. This is particularly important for forensic document examiners who may have to match a document of unknown origin with the equipment that may have produced it. A computerised system is expected to considerably reduce the time required for each document search. 相似文献
52.
Using signature techniques for information filtering in wireless and mobile environments 总被引:4,自引:0,他引:4
This paper discusses the issue of power conservation on mobile clients, e.g., palmtop, in wireless and mobile environments. It suggests that techniques using signatures are suitable for realtime information filtering on mobile clients. Three signature-based approaches, namely simple signature, integrated signature and multi-level signature schemes, are presented. The cost models for the access time and tune-in time of these three approaches are developed. We show that the multi-level signature method is in general better than the other two methods.Recommended by: Daniel Barbara, Ravi Jain and Narayanan Krishnakumar 相似文献
53.
G. Phanendra Babu Babu M. Mehtre Mohan S. Kankanhalli 《Multimedia Tools and Applications》1995,1(4):327-348
Content based image retrieval is an active area of research. Many approaches have been proposed to retrieve images based on matching of some features derived from the image content. Color is an important feature of image content. The problem with many traditional matching-based retrieval methods is that the search time for retrieving similar images for a given query image increases linearly with the size of the image database. We present an efficient color indexing scheme for similarity-based retrieval which has a search time that increases logarithmically with the database size.In our approach, the color features are extracted automatically using a color clustering algorithm. Then the cluster centroids are used as representatives of the images in 3-dimensional color space and are indexed using a spatial indexing method that usesR-tree. The worst case search time complexity of this approach isOn
q
log(N* navg)), whereN is the number of images in the database, andn
q
andn
avg
are the number of colors in the query image and the average number of colors per image in the database respectively. We present the experimental results for the proposed approach on two databases consisting of 337 Trademark images and 200 Flag images. 相似文献
54.
在X射线衍射仪上收集了Bi_4(SiO_4)_3的衍射数据;利用Rietveld方法对衍射数据进行指标化,F_(30)=158.90;确定了Bi_4(SiO_4)_3的晶体结构参数。结果发现:该结构中硅氧四面体是变形的孤立四面体,其中两个O-Si-O键角为107.13°,而另两个为114.26°,详细报道了晶体结构,给出了晶体结构图;提出Bi离子最外层孤对的6s2电子的存在是形成这种变形配位多面体的原因。 相似文献
55.
Automatic parsing and indexing of news video 总被引:9,自引:0,他引:9
Automatic construction of content-based indices for video source material requires general semantic interpretation of both images and their accompanying sounds; but such a broadly-based semantic analysis is beyond the capabilities of the current technologies of machine vision and audio signal analysis. However, if one can assume a limited and well-demarcated body of domain knowledge for describing the content of a body of video, then it becomes easier to interpret a video source in terms of that domain knowledge. This paper presents our work on using domain knowledge to parse news video programs and to index them on the basis of their visual content. Models based on both the spatial structure of image frames and the temporal structure of the entire program have been developed for news videos, along with algorithms that apply these models by locating and identifying instances of their elements. Experimental results are also discussed in detail to evaluate both the models and the algorithms that use them. Finally, proposals for future work are summarized. 相似文献
56.
57.
压缩域图像检索技术的研究 总被引:3,自引:0,他引:3
从检索和压缩相互结合的角度出发,针对现有压缩标准(如JPEG、MPEG、JPEG2000等),对基于DCT和DWT压缩域的检索技术进行了深入研究,提出了一系列新技术.实验结果表明,这种压缩和检索相互结合的研究思路是高效可行的,为进一步提高多媒体应用系统的整体性能奠定了坚实基础. 相似文献
58.
本文根据特征平行四边形法和N/(1/2)比值法提出了一种简便快速的电子衍射谱分析方法——图表法,由于它以一些简单的操作取代了常用分析法的数据测量和计算过程,因此具有简便、快速、可靠性高等优点。 相似文献
59.
通过理论以及具体实例的计算,分析了利用分度头进行差动分度的角度补偿原理,并以正反两个方向的角度补偿计算,揭示了差动分度的结果与假设等分分数的无关性。 相似文献
60.