Introduction One approach to developing an image retrieval system is to extend the existing information systems to include images. In this case images are accessed using alphanumeric data such as file name or image number. While this approach is easy, it has a limited capacity since the existing retrieval facilities were designed to accommodate alphanumeric and textual data. The other approach is to develop a new type of image retrieval system. This could include the development of a pattern matching based image retrieval system or a combination of that and the existing information systems.
Pattern recognition involves feature extraction, context processing and pattern classification.
In feature extraction, shapes and objects are identified through detecting edges and angles. Once the shape of the object is identified, it is measured to obtain quantitative values, or compared with previously stored patterns of objects. The next step is to apply some sort of discrimination function to classify the objects into one of many predetermined categories. The text can be processed automatically and every word in the text can be used to search the database. The architecture is very flexible.