Introduction

The digitization of multimedia data, such as images, graphics, speech, text, audio, video and 3D models, has made the storage of multimedia more and more convenient, and has simultaneously improved the efficiency and accuracy of information representation. With the increasing popularization of the Internet, multimedia communication has reached an unprecedented level of depth and broadness, and multimedia distribution is becoming more and more manifold. People can distribute their own works over the Internet, search and download multimedia data, and also carry out electronic trade over the Internet. However, some serious issues accompany this as follows: (1) How can we efficiently transmit and store huge multimedia information with limited bandwidth and storage capacity? (2) How can we prevent multimedia works from being pirated and tampered with? (3) How can we search for the desired multimedia content in huge multimedia databases?.