Free viewpoint images can be generated from multi-view images using Ray-Space method. Ray-Space data requires ray interpolation so as to satisfy the Plenoptic Function. Ray interpolation is realized by estimating view-dependent depth. Depth estimation is usually costly process, thus it is desirable that this process is skipped from rendering process to achieve real-time rendering. This paper proposes a method to render a novel view image using multi-view images and depth maps which are computed in advance. Virtual viewpoint image is generated by 3D warping, which causes some problems that have not occurred in the method with view dependent depth estimation. We handled these problems by projecting depth map to virtual image plane first and perform post-filtering on the projected depth map. We succeeded in obtaining high quality arbitrary viewpoint images from relatively small number of cameras.

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In this article we investigate the effect of playout buffering control in haptic media, sound, and video transmission via QoE (Quality of Experience) assessment. We assess the operability of the haptic interface device, sound output quality, video output quality, inter-stream synchronization quality, and comprehensive quality. We also evaluate the application-level QoS (Quality of Service), and demonstrate that, with high accuracy, it is possible to estimate QoE parameters from QoS parameters.

In this paper, we investigate the influences of network delay on QoE (Quality of Experience) such as the operability of haptic interface device and the fairness between players for soft objects in a networked real-time game subjectively and objectively. We handle a networked balloon bursting game in which two players burst balloons (i.e., soft objects) in a 3D virtual space by using haptic interface devices, and the players compete for the number of burst balloons. As a result, we find that the operability depends on the network delay from the local terminal to the other terminal, and the fairness is mainly dependent on the difference in network delay between the players' terminals. We confirm that there exists a trade-off relationship between the operability and the fairness. We also see that the contribution of the fairness is larger than that of the operability to the comprehensive quality (i.e., the weighted sum of the operability and fairness). Assessment results further show that the output timing of terminals should be adjusted to the terminal which has the latest output timing to maintain the fairness when the difference in network delay between the terminals is large. In this way, the comprehensive quality at each terminal can be maintained as high as possible.

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