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Shota KASAI Yusuke KAMEDA Tomokazu ISHIKAWA Ichiro MATSUDA Susumu ITOH
We propose a method of interframe prediction in depth map coding that uses pixel-wise 3D motion estimated from encoded textures and depth maps. By using the 3D motion, an approximation of the depth map frame to be encoded is generated and used as a reference frame of block-wise motion compensation.
Yoshinori ROKUGO Kazushi TAHARA Joji MAEDA Susumu ITOH
When digital broadcasting services are provided through cable television (CATV) networks, viewers watching interactive programs such as quizzes or auctions may respond to the program within a short period. If these responses are transmitted in the upstream channel of the CATV networks using TCP/IP, they will result in burst traffic. The numerous TCP connections will trigger congestion in the upstream transmission facilities and will cause a significant delay in conventional Internet services such as web-browsing. The present paper proposes a new method of controlling the CATV upstream channel to avoid such congestion. We introduce class-based queues at each cable TV station, in which each service class is related to a type of interactive service. The status of the queue is relayed to the cable modems of subscribers using a CATV-specific MAC protocol. This queue-status information is used to suspend further initiation of TCP connections at cable modems. As a result, the TCP connections will be arbitrated in the CATV network, while the delay of the response transmission is traded for smoothing of the burst traffic. We numerically evaluate the effect of the proposed method using the time distribution of responses to an actual quiz program. The results show that the proposed method successfully suppresses interference of the burst traffic with conventional best-effort services.
Toru SUMI Yuta INAMURA Yusuke KAMEDA Tomokazu ISHIKAWA Ichiro MATSUDA Susumu ITOH
We previously proposed a lossless image coding scheme using example-based probability modeling, wherein the probability density function of image signals was dynamically modeled pel-by-pel. To appropriately estimate the peak positions of the probability model, several examples, i.e., sets of pels whose neighborhoods are similar to the local texture of the target pel to be encoded, were collected from the already encoded causal area via template matching. This scheme primarily makes use of non-local information in image signals. In this study, we introduce a prediction technique into the probability modeling to offer a better trade-off between the local and non-local information in the image signals.
Yuta ISHIDA Yusuke KAMEDA Tomokazu ISHIKAWA Ichiro MATSUDA Susumu ITOH
This paper proposes a lossy image coding method for still images. In this method, recursive and non-recursive type intra prediction techniques are adaptively selected on a block-by-block basis. The recursive-type intra prediction technique applies a linear predictor to each pel within a prediction block in a recursive manner, and thus typically produces smooth image values. In this paper, the non-recursive type intra prediction technique is extended from the angular prediction technique adopted in the H.265/HEVC video coding standard to enable interpolative prediction to the maximum possible extent. The experimental results indicate that the proposed method achieves better coding performance than the conventional method that only uses the recursive-type prediction technique.
Shu TAJIMA Yusuke KAMEDA Ichiro MATSUDA Susumu ITOH
This paper proposes an efficient lossless coding scheme for color video in RGB 4:4:4 format. For the R signal that is encoded before the other signals at each frame, we employ a block-adaptive prediction technique originally developed for monochrome video. The prediction technique used for the remaining G and B signals is extended to exploit inter-color correlations as well as inter- and intra-frame ones. In both cases, multiple predictors are adaptively selected on a block-by-block basis. For the purpose of designing a set of predictors well suited to the local properties of video signals, we also explore an appropriate setting for the spatiotemporal partitioning of a video volume.
Yuya KAMATAKI Yusuke KAMEDA Yasuyo KITA Ichiro MATSUDA Susumu ITOH
This paper proposes a lossless coding method for HDR color images stored in a floating point format called Radiance RGBE. In this method, three mantissa and a common exponent parts, each of which is represented in 8-bit depth, are encoded using the block-adaptive prediction technique with some modifications considering the data structure.
Tohru IKEGUCHI Kazuyuki AIHARA Susumu ITOH Toshio UTSUNOMIYA
Electroencephalographic (EEG) potentials are analysed by the Lyapunov spectrum in order to evaluate the orbital instability peculiar to deterministic chaos quantitatively. First, the Lyapunov spectra are estimated to confirm the existence of chaotic behavior in EEG data by the optimal approximation of Jacobian matrix in the reconstructed statespace. Second, the same method is applied to a neural network model with chaotic dynamics, the macroscopic average activity of which is analysed as a simple model of EEG data. The first analysis shows that the largest Lyapunov exponent is actually positive in the EEG data. On the other hand, the second analysis on the chaotic neural network shows that the positive largest Lyapunov exponent can be obtained by observing only the macroscopic average activity. Thus, these results indicate the possibility that one can know the existence of chaotic dynamics in the brain by analysing the Lyapunov spectrum of the macroscopic EEG data.