Prace dotyczące ruchomych obrazów swobodnego punktu widzenia (free-viewpoint video) prowadzone są w Katedrze Telekomunikacji Multimedialnej i Mikroelektroniki Politechniki Poznańskiej.

The paper presents Improved Adaptive Arithmetic Coding algorithm for application in future video compression technology. The proposed solution is based on the Context-based Adaptive Binary Arithmetic Coding (CABAC) technique and uses the authors mechanism of symbols probability estimation that exploits Context-Tree Weighting (CTW) technique. This paper proposes the version of the algorithm, that allows an arbitrary selection of depth D of context trees, when activating the algorithm in the framework of the AVC or HEVC video encoders. The algorithm has been tested in terms of coding efficiency of data and its computational complexity. Results showed, that depending on depth of context trees from 0.1% to 0.86% reduction of bitrate is achieved, when using the algorithm in the HEVC video encoder and 0.4% to 2.3% compression gain in the case of the AVC. The new solution increases complexity of entropy encoder itself, however, this does not cause an increase of the complexity of the whole video encoder.

In the paper, two preprocessing methods for virtual view synthesis are presented. In the first approach, both horizontal and vertical resolutions of the real views and the corresponding depth maps are doubled in order to perform view synthesis on images with densely arranged points. In the second method, real views are filtered in order to eliminate blurred or improperly shifted edges of the objects. Both methods are performed prior to synthesis, thus they may be applied to different Depth-Image-Based Rendering algorithms. In the paper, for both proposed methods, the achieved quality gains are presented.

"Free-viewpoint video" technology, under development at the Poznań University of Technology, will enable viewers to watch video from varying points located on a virtual trajectory of their own selection.