Self-calibration algorithms that use only the information in the image have been actively researched. However, most algorithms require bundle adjustment in the projective reconstruction or in the nonlinear minimization. We propose a practical self-calibration algorithm that only requires a linear projective reconstruction. We overcome the sensitivity of the algorithm due to image noises by adding another constraint on the principal point. Also, we propose a variant of linear auto-calibration algorithm which uses the similar assumption of the work of Pollefeys et al. (1998), based on the property of the absolute quadric. Experimental results using real and synthetic images demonstrate the feasibility of the proposed algorithm.

Interactive broadcast terminal system was designed for bidirectional interactive television service based on the MPEG-2/4 standards and ATSC broadcast specification. In order to implement user interactivity, MPEG-4 contents are carried by MPEG-2 PES or private section. Additional information combined as XML format is transmitted by DSM-CC data carousel while ATSC-PSIP is used to transfer the EPG information. IP is used to handle the bi-directional user interaction data through return channel.

This paper describes architecture of a streaming system for interactive digital television broadcast, using MPEG-4/7 technology in delivering interactive services. The streaming system complies with ATSC (Advanced Television Systems Committee) Digital Television Standard, and delivers data of all types in ATSC Data Broadcast specification. The streaming system provides transport streams conforming to MPEG-2 systems, and has been implemented on the basis of software, and in several parts in hardware.