To my parents for providing endless energy. To my brothers for giving me an opportunity to study overseas. Multimedia plays an important role in current information society since multimedia efficiently represent perceptional data. Textual...
moreTo my parents for providing endless energy. To my brothers for giving me an opportunity to study overseas. Multimedia plays an important role in current information society since multimedia efficiently represent perceptional data. Textual data, audio, images, and video are integrally called multimedia. Image is one of the most popular mediums. An image is a two dimensional signal stored as an array of pixels and symbolises visual information. " One image is worth thousand words" would be a sentence describing the information reflecting image meaning. It is clear that how to describe image meaning completely is difficult. This directly testifies that images effectively convey information rather than text. Moreover, many constituent complex sentences can be represented by an image. For example, novel computer operating systems such as windows 98 prefer to use graphical user interface such as icons instead of complicated commands. In addition, the use of images makes the deprivafion of descripfion problems to appear. For instance, advertising designers can visually demonstration their goods to prospective customers in order to query and generate orders. The problem of how to access and manage non-textual information is progressively apparent as expressed by the nature of image data, the storage requirements, the image representations, and the rapid growth of the use of image data. In this thesis, image INTRODUCTION meaning is obscure, and the access of image is problematic. Therefore, it is clear that the techniques achieve a high degree of compression, regardless of the information management perspective. Finally, users rapidly migrate from textual data services to multimedia services. This stems from two main reasons. Firstly, multimedia presentation perceptually conveys information. This makes an efficient communication process, and most information is comprehensive. This forms the new medium for information interchange. Secondly, a global network for information interchange is available. The Internet is the biggest network connecting the world. The Internet services such as world-wide-web encourage interchange of information among users. This is more so when users have easily understandable data stream like multimedia. Furthermore, the running cost of the Internet services is affordable for personal use. As indicated by the natural mean of multimedia, content-based retrieval of multimedia data is more appropriate. Supporting this heuristic, MPEG-7 standard aims to address this issue. From the information management perspective, retrieval of small data sets from a large collection of data streams is a central idea. Tremendous data streams are a significant impediment for retrieval. Fortunately, existing compression techniques obtain a high degree of compression. However, again, the techniques only support efficiency of storage and transmission management. They are developed based on representation models. The models include, (i) pixel intensities, (ii) pixels grouping to vectors, (iii) two dimensional grouping of pixels into regions occupying stationarity, and (iv) two dimensional grouping into region of pixels retaining high level semantic scheme such as object. Content-based choice of features. For instance, sub-string matching [67] is appropriate for keywords. The success of any feature set in measuring similarity depends more or less on the use of an appropriate metric. From the literature, existing image databases are specific to applications and are not supportive to content-based retrieval. Image retrieval in most of the systems is equivalent to content-based retrieval systems. Moreover, design criteria for retrieval systems are highlighted. Finally, a retrieval model is proposed for further experiments. Chapter 3 presents three image features that will be used for retrieval and discusses their characteristics. As similarity measures, the image metrics corresponding to the features are also briefly described. Recent studies indicate that content-based retrieval is more appropriate for multimedia data streams. From these studies, the solutions are not completely provided. Content-based retrieval relates to at least three aspects, namely the retrieval, database, and data representation aspects. This thesis aims to address the retrieval aspect. Conceptual issues of content-based retrieval are studied. An image model that is persuasive to content-based retrieval is proposed. From the retrieval point of view, the thesis nominates three features, namely the Zemike moments, the Fourier descriptors, and the wavelet descriptors. The features are extracted