New Approaches for Image Retrieval

Images and graphics are among the most important media formats for human communication and they provide a rich amount of information for people to understand the world. With the rapid development of digital imaging techniques and internet, more and more images are available to public. Consequently, there is an increasingly high demand for effective and efficient image indexing and retrieval methods, and image retrieval has become one of the most popular topics in the ¿eld of pattern recognition and arti¿cial intelligence. An image retrieval system is a computer system for browsing, searching and retrieving images from a large volume of digital images. Generally speaking, there are three categories of image retrieval methods, i.e. text based, content-based and semantic-based methods. The term has since been widely used to describe the process of retrieving desired images from a large collection on the basis of features (such as color, texture and shape) that can be automatically extracted from the images themselves. The features used for retrieval can be either primitive or semantic, but the extraction process must be predominantly automatic. Retrieval of images by manually-assigned