A survey on content-based retrieval for multimedia databases <s> Motion of Object <s> Abstract Recent progress in hardware and operating system technologies has made it possible to manage multimedia data consisting of text, static images, sound and/or video. Video data is considered to be the most informative of these types of data. It presents a scene consisting of objects and the motion of objects conveying particular meaning of the scene. Thus, the inherent feature of video data lies in the motion of objects. In this paper, we present a system that retrieves video data by means of the motion of objects observed in the video data in the database. The system accepts a query for a video database, which is specified by drawing an example trajectory of an object, and retrieves video data by extracting a moving object observed in the video data. The proposed way of specifying a query condition is superior to other ways of representing a condition, e.g. by text, in the sense that it is suitable for representing the difference of motion. <s> BIB001 </s> A survey on content-based retrieval for multimedia databases <s> Motion of Object <s> The rapidity with which digitat information, particularly video, is being generated, has necessitated the development of tools for efficient search of these media. Content based visual queries have been primarily focussed on still image retrieval. In this papel; we propose a novel, real-time, interactive system on the Web, based on the visual paradigm, with spatio-temporal attributesplaying a key role in video retrieval. We have developed algorithms for automated video object segmentation and tracking and use real-time video editing techniques while responding to user queries. The resulting system pe$orms well, with the user being able to retrieve complex video clips such as those of skiers, baseball players, with ease. <s> BIB002
QBE for image data becomes applicable to video databases as well, if we can regard a piece of video data as a set of images whose temporal interrelation is not interested. Specifying a sketch for retrieving a frame in video streams cannot always be proper, since this method of query specification loses information specific to video data, i.e., spatiotemporal relation/contents. QBE with motion examples is an approach to retrieve intrinsic features of video data, i.e., the motion of objects appearing in video. The authors have implemented a system which makes retrieval of video data possible by specifying the motion of an object observed in video data by giving an example BIB001 (see Fig. 3 ). An example motion of an object is specified by making a mouse move, and then a trajectory and velocity are sampled in accordance with the movement. In addition, changing the size of an object is specified by drawing rectangles along with the timeline. Another example of QBE with motion example is presented in BIB002 . This work also allows a user to specify trajectory, duration, and scaling as well as the basic feature of image such as color, texture, and shape. The proposed framework allows us to specify an example consisting of multiple objects. However, specifying a number of objects as an example is too complicated.