Tsuyoshi Hanamura

Hierarchical coding scheme of video signal with scalability and compatibility

Abstract A video coding scheme that enables hierarchical video signal processing in MPEG II is proposed in this paper. Dividing each input picture into hierarchical layers, a proposed prediction is applied into each layer. The proposed coding scheme is to be characterized on the following points: (1) Non-interlaced pictures for each layer picture, even for the highest resolution layer. (2) Hierarchical motion estimation to provide precise motion vectors in less process time, to each layer of pictures. (3) Hierarchical prediction and layer pictures to provide various size of video signal for display, and to be compatible with MPEG I. (4) Up-sampling and down-sampling processes without phase distortion between neighbor layers. Other functions are almost the same as MPEG I. As the experimental result, the quality of decoded pictures highly depends on the quality of non-interlaced pictures that are provided from the pre-process.

A Motion Detection Method on Video Image by Using Hierarchical Pixels

It is not easy to extract significant information from image data concerning the motion and the structure of an object, but this technique is indispensable to the future development of video coding and recognition of a moving object. The block matching method [1] is employed widely as a motion detection method in the motion-compensated interframe coding. However, it has a problem in that the motion is estimated by the prediction error power minimization condition, which may lead to an instability in accurate motion detection. This paper proposes a new block matching method that has the following features: the motion is estimated and detected by stepwise switching from larger block size to smaller block size; by this scheme, the motion detection accuracy and the spatial resolution can be improved, and the processing complexity can also be reduced without degrading the detection accuracy.

A video coding method considering cell losses in ATM-based networks

Abstract This paper describes a video coding method which is capable of compensating for information losses due to cell discard. The proposed method separates picture elements into two groups by using quincunx subsampling. Separated picture elements are coded severally. Picture elements in one group are called higher priority pixels and their coded data are transmitted in higher priority cells, while ones in the other called lower priority pixels and their coded data are transmitted in lower priority cells. In case of network congestion, the proposed method prevents fatal degeneration in image quality by selectively discarding lower priority cells. Furthermore we take into consideration that higher priority cells are not always free from discard. As a countermeasure against losses of higher priority cells, we examine two schemes, one of which is called intrablock prediction and the other is cyclic refreshing. Experimental results show that the proposed method effectively suppresses degradation in image quality compared with conventional coding methods.

A proposal of multimedia document architecture and video document architecture

The concepts of MDA, multimedia document architecture, and VDA, video document architecture, are proposed. Harmonization with existing multimedia architectures and integration of media are described, introducing a multimedia space. A multimedia meta-structure is centered in this multimedia space. A projection of the meta-structure to an axis or a plane of multimedia space makes a mapping to a specific media architecture. Each axis is considered as a multimedia element. As a candidate for a multimedia element in multimedia space, VDA is also proposed in order to edit video information. The time-domain structure and the scenery structure for it are introduced. The video processing model is also described.<<ETX>>

Scalable video transmission by separating and merging of MPEG-2 bitstream

In this paper, we propose a scalable video transmission system based on transcoding. First, we focus on the transcoder to reduce the bitrate of MPEG-2 bitstreams. We show that it is realized the layered coding by using the differential data between input and output of a transcoder. Next, we show the coding algorithm of this differential data. This algorithm can improve the coding efficiency by removing unnecessary code for differential data. By simulation experiments, we show that the proposed coding algorithm prevents the loss of coding efficiency in traditional hierachical coding, and show the effectiveness of proposed scheme.

MPEG-2 multi-program transport stream transcoder

MPEG-2 Multi-program Transport stream (TS) achieves improvement of transmission efficiency by multiplexing several MPEG-2 streams. In this paper, we propose a transcoder which achieves rate reduction of MPEG-2 multi-program TS. For the purpose of realizing MPEG-2 multi-program TS transcoder, this transcoder requires a rate control method and re-multiplexing method: The former improves average SNR values in total of streams, and the latter achieves the evasion from failure of STD buffer. Next, from simulation experiments, we compare the conventional rate control methods to the proposed one. On the other hand, we show the state of STD buffer. Finally, we show the effectiveness for our proposed scheme.

ISO/IEC software implementation of MPEG-1 video

The MPEG-1 video standard, ISO/IEC 11172 Part 2, specifies the syntax and the semantic rules by which bitstreams are generated in the encoder, and arithmetic rules by which pictures are reconstructed in the decoder. The actual encoder model is left open to the designer to choose among different cost and quality tradeoffs. An example encoder strategy is described in the informative annex D. A technical report giving a full encoder and decoder implementation expressed in the ANSI C programming language will become the fifth part of the ISO/IEC 11172 document. The encoder is based on a test model shaped by participants of the MPEG committee that produces good picture quality while exercising the full video syntax. The decoder employs full arithmetic accuracy at all stages, and include bitstream conformance checks. Finally, a companion systems codec demonstrates the temporal link between the systems and the video layers. To better serve as a learning tool for novices, the code is optimized for clarity rather than execution speed. In addition to an overview of the program, this paper provides a brief description of the encoder model.

Packet-multiplexing scheme in MPEG-2 multi-program transport stream transcoder

We describe a computer vision based mouse, which can control and command the cursor of a computer or a computerized system using a camera. In order to move the cursor on the computer screen the user simply moves the mouse shaped passive device placed on a surface within the viewing area of the camera. The video generated by the camera is analyzed using computer vision techniques and the computer moves the cursor according to mouse movements. The computer vision based mouse has regions corresponding to buttons for clicking. To click a button the user simply covers one of these regions with his/her finger.As an appliance that achieves rate reduction of MPEG-2 multi-program transport streams, MPEG-2 multi-program transport stream trans coder has been proposed. This transcoder needs to multiplex packets without any STD buffer failure. However, no efficient packet-multiplexing scheme has been reported until now. In this paper, we propose packet-multiplexing scheme that no STD buffer failure occurs in MPEG-2 multi-program transport stream transcoder. This proposed scheme is implemented by the following ways: 1) PSI packets are output in constant interval, 2) audio packets are output in the same PCR as that of input transport stream, 3) video packets are output so that the intervals of each output packet for every video elementary stream should be constant. From simulation experiments, we show the status of STD buffer and show the effectiveness for our proposed scheme.

Rate control scheme for low-delay MPEG-2 video transcoder

In this paper, we focus on the video transcoder as a bit rate reducer in a network node and propose a rate control scheme for a low-delay MPEG-2 video transcoder. First, we summarize the requirements of a rate control algorithm for low-delay transcoding. Next, based on these requirements, we describe the proposed rate control scheme in detail. Then, we analyze the input and output buffer delay and calculate the total delay time of the proposed transcoder. Finally, we evaluate the proposed scheme from the simulation results of experiments on picture quality, transcoding delay time and GOP (Group Of Pictures) structure information (N/M value) of the input bit stream. Consequently, we showed that the proposed scheme can provide the same picture quality as a traditional scheme and is independent of the GOP structure.

Processible video codec on camera operations

This paper proposes processible video codec on camera operations (PVCC) which uses two video data (camera parameters and image contents) to improve the efficiency of video editing. Image data are separated in the coding; they are selected and synthesized in the decoding. Conditions are set for the relationship between the positions of a camera and its object so that data separation is simplified in the decoding. The system using test patterns shows that the system has an average SNR of about 50 [dB] with accurate camera parameters, the value being sharply deteriorated with an increase of errors in the parameters. Simulations of camera operation and data editing successfully confirm the expected effect of the proposed method. A simple language describing the camera improves the speed of video editing and increases content readability.