Depth Estimation in Free-Viewpoint Television

The development of a novel depth estimation method for free viewpoint television systems is the main goal of research presented in this dissertation. In free-viewpoint television the functionalities offered to a viewer are extended by the possibility of controlling the displayed viewpoint of a scene. The dissertation presents an analysis of the depth estimation process in the scope of free-viewpoint television (FTV) systems. The author of the dissertation defines a set of requirements, which are not met by state of the art methods of depth estimation, and that should be met by a new depth estimation method designed for free-viewpoint television. The main focus is put on the influence of the quality of estimated depth maps on the quality of virtual views and on an analysis of the high complexity of depth estimation. The fundamentals of depth estimation, together with state of the art methods of depth estimation, are also described. The novel method for depth estimation proposed by the author of the dissertation consists of three primary achievements of this dissertation: the inter-view consistent segment-based depth estimation method, the temporal consistency enhancement that simultaneously increases temporal consistency of depth maps and reduces the complexity of estimation, and a new method of parallelisation for graph-based depth estimation methods. The experimental results contain a comparison of the proposed depth estimation method with the reference method provided by the ISO/IEC MPEG group. The efficiency of the proposed method for variable estimation parameters and the results for the proposed methods of temporal enhancement and parallelisation were also included in the dissertation. This dissertation also includes a description of new test sequences that are available for the research community and include depth maps estimated using the method proposed by the author. The depth estimation method that is the result of research presented in this dissertation is also a part of the free viewpoint television system developed by the Chair of Multimedia Telecommunications and Microelectronics of Pozna? University of Technology. These achievements prove the high usability of the presented depth estimation method in real FTV systems.