MPEG-7 Visual Identifier

Digital visual information(image and video) plays an important role in our society, and everyday, more and more visual information is available from many sources around the world. And there is an increasing number of cases where the these visual informations are created, stored, retrieved, and re-used by computational systems. But information modification, distortion and compilation occurred through trans-coding or legal/illegal information processing often make these operations difficult. Subordinately, advanced technology or commercialized software for retrieving and identifying the desired information among these massive and diverse ones is strongly required. In the paper, some recent activities and technical content of MPEG-7 Visual Group are described, especially with regarding to Visual Identifier.