Hideyoshi Tominaga

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>>

Camera working parameter extraction for constructing video considering camera shake

With the increasing popularity of high-performance DV cameras and video editing applications on PC, desktop videos have become more attractive. Video editing and summary, however, still poses problems as it lacks useful support tools, which can efficiently show the video contents to editors. Against this background, our goal is to build a useful video-editing system grounded on techniques of content analysis. On the basis of our video document architecture concept, we regard camera work parameters as a means of reference to construct video. Camera work parameters can be defined follows: (1) a variety of camera work patterns (such as panning and zooming, etc.); and (2) the quality of camera work of speed and camera shake rate. By calculating these parameters, we aim to build a system, enabling one to detect significant scene candidates from the original shot sequence as well as edit videos automatically.

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.

Vector representation of binary images containing halftone dots

Vector representation of graphics has the advantage that the image can be displayed at any size. When the resolution of a bitmap image is changed, the lack of a line segment arises. In addition, moire occurs when the resolution of an image with halftone dots is changed. We propose a new technique to convert a binary image with halftone dots into its vector representation. Resolution conversion of a binary image can easily be performed without moire by using a continuous tone approximation of the halftone dots. First, we separate the area of halftone dots and line drawings in the image. Next, a continuous tone approximation is applied to the area of halftone dots. Then, conventional vectorization is applied to both continuous tone areas and line drawings. Finally, these components are mixed and reconstructed. Our approach provides an efficient way of displaying cartoon-like images at any size with a limited amount of data.

Adaptive resolution image acquisition using image mosaicing technique from video sequence

We propose a layered image mosaicing method from a video sequence to acquire an adaptive resolution image. In research of art, for example, researchers often desires the full view of a painting and the details of certain regions, where fine brush-strokes are in it. The proposed method is to acquire the region of special interest at a fine resolution and the remaining image space at a coarser resolution by using a hand-held video camera which repeats moving, panning, tilting, zooming in and zooming out. To integrate video frames, image mosaicing methods can be used. However, existing mosaicing methods, in general, have a defect, where they perform inefficiently because wide angle image frames are registered after magnification. To solve this problem, the layered image mosaicing method is proposed. The proposed method can reduce processing time while it makes a mosaic image accurately. In this paper, the concept, algorithm and experiments are described. The experiments showed that the method was efficient and accurate for acquisition of an adaptive resolution image.

A study on two-layer coding for animation images

A coding scheme specifically designed for animation images is proposed. Taking the characteristics of animation images into account, lines and homogeneous color regions are extracted from animation images. Lines and contours of the homogeneous color regions are approximated by straightline and spline functions. We found that smoothing operations are effective to extract homogeneous regions from background images. A connected filter is used for the smoothing operation while keeping edges of the original image correctly. Precise approximation of the contours is also required. For this purpose, we propose to use dynamic programming with a feedback algorithm. As a result, an animation image can be represented by two layers; significant points as a base layer, and discrete cosine transform (DCT) blocks for an additional layer. For the compensation of the loss caused by the smoothing operation, the DCT is applied to the difference between the original images and lines and homogeneous color regions images. High-quality images can be obtained by adding this differential data to the approximated images.

A routing-aware handover scheme for mobile IP

One of the main issues of mobile IPv6 is handover latency that causes service disruption time. Although plenty of proposals significantly reduce the service disruption time, they suffer from redundant routing that causes packet misordering and bandwidth consumption during the process of inter-domain handover. In this paper, we propose R-MIP, a routing-aware handover scheme for mobile IP, that minimizes the redundant routing during the process of inter-domain handover by utilizing forwarding routers. R-MIP consists of forwarding router discovery and proactive handover. We evaluate R-MIP in the view of packet misordering and bandwidth consumption, and clarify its efficiency. We also evaluate the impact of the forwarding routers capacity since routers have limited resources. By strategically locating forwarding routers, e.g. next to the router that has peering to another domain, the redundant routing caused by inter-domain handover will be efficiently suppressed.