**5.1. Introduction of multi-view video and open problem**

The developments of camera and display technologies make recording a single scene with multiple video sequences possible. These multi-view video sequences are taken by closely spaced cameras from different angles. Each video sequence in the multi-view video presents a unique viewpoint of this scene. Therefore, user can switch the viewpoint by playing different video sequences. When a robot is equipped with multi-cameras, it will bring the user who controls the robot a broad perspective. The operator also can switch his viewpoints by playing different video sequences. However, since the multi-view video consists of the video sequences captured by multiple cameras, the traffic of multi-view video is several times larger than conventional multimedia, which brings the dramatic increase in the bandwidth requirement. However, as multi-view video is taken from the same scene, a large amount of inter-view correlation is contained in the video. Therefore, compression transmission technologies are especially important for multi-view video streaming.

The state of the art in multi-view representations includes Multi-View Video Plus Depth (Merkle et, al., 2007), Ray-Space (Smolic, et, al., 2006) and Multi-view Video Coding (MVC) (Vetro, et, al., 2008), (Mueller, et, al., 2006). However, the research on Multi-View Video Plus Depth sequences (Merkle et, al., 2007) suggests that with the addition of depth maps and other auxiliary information, the bandwidth requirements could increase. MVC is issued as an amendment to H.264/MPEG-4 AVC (Vetro, et, al., 2008), (Mueller, et, al., 2006). It was reported that MVC makes more significant compression gains than simulcast coding in which each view is compressed independently. However, even with the MVC, transmission bitrates for multi-view video are still high: about 5 Mbps for 704 × 480, 30fps, and 8 camera sequences with MVC encoding (Kurutepe, et, al. 2007).
