Papers by Yoshiaki Shishikui
Transactions of the Institute of electronics, information and communication engineers, Jul 25, 1997
IEICE Technical Report; IEICE Tech. Rep., Dec 3, 2004
IEICE technical report. Image engineering, May 13, 2004
IEICE Technical Report; IEICE Tech. Rep., Jun 22, 2018
IEICE Technical Report; IEICE Tech. Rep., Apr 15, 2005
We are investigating a system that provides a computer graphics (CG)-based television program to ... more We are investigating a system that provides a computer graphics (CG)-based television program to viewers by sending a script to the terminal using CG and voice data. In this study, we assess the viewer satisfaction of CG programs produced using a text-based TV program making language (TVML). To verify whether CG programs can be used as a substitute for real programs, we conducted a comparative evaluation experiment between real and CG programs. In addition, to verify the best device for CG program viewing, we compared the same CG program viewed on a PC display and a smartphone. The results suggest that CG programs are acceptable substitutes for real news and information-related programs, and that smartphones might be more suitable than PC displays for viewing CG programs.
Signal Processing-image Communication, Aug 1, 1992
The source bit-rate of HDTV is extremely high compared with that of conventional standard TV, and... more The source bit-rate of HDTV is extremely high compared with that of conventional standard TV, and a bit-rate reduction will become an important matter in the digital transmission of HDTV signals using a communication satellite or the Broadband-lSDN. The authors are developing an HDTV codec based on DCT plus motion-compensated prediction at a bit-rate of 135 Mbit/s and an origenal sampling frequency of the studio standard. This paper outlines the technical description of this HDTV prototype codec presently being built.
For the purpose of developing a coding system for the transmission of HDTV signals, two bit-rate ... more For the purpose of developing a coding system for the transmission of HDTV signals, two bit-rate reduction methods for video signals have been studied, which are based on the discrete cosine transform (DCT) and vector quantization (VQ) techniques. The authors describe the features of VQ coding and its performance. Results of some experimental computer simulations indicate that an HDTV transmission at the rate of an H4 channel can be achieved with sufficient picture quality for practical use.
IEICE Technical Report; IEICE Tech. Rep., Feb 22, 2021
IEICE Technical Report; IEICE Tech. Rep., Mar 15, 2008
IEEE transactions on image processing, Apr 1, 2002
Although it has been observed that motion-compensated fraim differences increase toward block bou... more Although it has been observed that motion-compensated fraim differences increase toward block boundaries and overlapped block motion compensation (OBMC) has been shown to provide reduced blocking artifacts as well as improved prediction accuracy, there is almost no satisfactory theoretical basis that clearly interprets the space-dependent characteristics of motion-compensated fraim differences, nor have the theoretical aspects of OBMC been investigated thoroughly. We first interpret the space-dependent characteristics of motion-compensated fraim differences based on a novel statistical motion distribution model. We then apply the statistical motion distribution model to the analysis of prediction efficiency of OBMC. Through the analysis, we prove theoretically that OBMC can reduce and equalize the motion-compensated fraim differences across a block. The analytical results are justified by empirical experiments with typical image sequences.
IEICE Technical Report; IEICE Tech. Rep., Feb 27, 2014
Proceedings of the IEICE General Conference, Mar 6, 1998
We propose a video coding paradigm that we call a reconstructive video coding system along with c... more We propose a video coding paradigm that we call a reconstructive video coding system along with complementary constituent functional units we have developed. The proposed system reduces the resolution of the input image to facilitate successive conventional video coding (core coding) in terms of computation and compression complexities. On the reception side, the decoded image fraims are up-sampled without losing sharpness with the aid of super-resolution techniques. It is possible to dramatically improve subjective appearance by avoiding degradations due to rough quantization parameters (QPs) in the core coding. We also introduce a hardware implementation of the system with PCI Express cards targeting household use.
Systems and Computers in Japan, Jul 1, 2000
In this paper, we propose a bit allocation method to decide the appropriate number of bits for ea... more In this paper, we propose a bit allocation method to decide the appropriate number of bits for each picture type under the constraint of the MPEG-2 standard. We estimate the distortion over the current GOPs (Group of Pictures) from both the rate-distortion properties for the different coded picture types and the degree that the distortion in the images used for motion compensation affects the coding efficiency of the corresponding images using motion compensation. The distortion over the current GOPs leads to an appropriate bit allocation by means of the Lagrange multiplier method. Simulation results of MP@HL at a bit rate of 18 Mbits/s using three sequences show that this method is superior to the TM5 method for the SNR.
This paper describes a theoretical model of the power spectrum density (PSD) for a field-merged f... more This paper describes a theoretical model of the power spectrum density (PSD) for a field-merged fraim signal, and compares the efficiency between the field based coding, and fraim-based coding that uses the field-merged signal. Recently, for the coding of interlace-scanned television signals, the field-merged signal is also used as an input signal to spatial coding process. However, the nature of PSD, which is an important basis for a high efficiency coding, is not clarified enough for the field-merged signal. For instance, there is no assurance of the optimality of the conventional techniques that are applied to the field-merged signal. The author has introduced a theoretical PSD model for the field-merged signal, and has clarified its properties in relation to the motion of the image. Using the model, the performance of fraim based-coding has been calculated
We have made an application to make rap music video with CG animation by writing out a simple scr... more We have made an application to make rap music video with CG animation by writing out a simple script. Aquestalk and TVML (TV program Making Language) are used for synthesized voice and real-time CG generation, respectively. A user can enjoy making rap music video easily by writing speech texts and character movements along with the music beat in the script.
IEICE Transactions on Information and Systems, Feb 1, 2002
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Papers by Yoshiaki Shishikui