Fumio Kishino

Variable bit-rate coding of video signals for ATM networks

Statistical characteristics of video signals for video packet coding, are clarified and a variable-bit-rate coding method for asynchronous transfer mode (ATM) networks is described that is capable of compensating for packet loss. ATM capabilities are shown to be greatly affected by delay, delay jitter, and packet loss probability. Packet loss has the greatest influence on picture quality. Packets may be lost either due to random bit error in a cell header or to network control when traffic is congested. A layered coding technique using discrete-cosine transform (DCT) coding is presented which is suitable for packet loss compensation. The influence of packet loss on picture quality is discussed, and decoded pictures with packet loss are shown. The proposed algorithm was verified by computer simulations. >

Packet video transmission through ATM networks

The basic aspects of packet video transmission technology are described, and some new results are presented. The advantages of packet video transmission through ATM (asynchronous transfer mode) networks and items to be solved are discussed from both the network and the user sides. Modeling methods, including burstiness measures are described. Examples of modeling based on the Markov modified Poisson process are shown. Packet loss protection and recovery methods are discussed, and the effects of a layered coding scheme are described. Subjective picture quality based on variable rate video transmission is demonstrated.<<ETX>>

Study on a stereoscopic display system employing eye-position tracking for multi-viewers

We propose a new autostereoscopic display system employing an eye-position tracking technique for multi-viewers who do not need to wear 3-D glasses. We also describe the developed stereoscopic projectors and the lenticular screen design for this system. In this system, the 3-D screen consists of two lenticular screens and a diffusion layer. Each 3-D projector that corresponds to a viewer consists of two projectors for right and left images. The viewers positions are detected, and the 3-D projector moves according to the viewers movement.

Allowable delay time of images with motion parallax and high-speed image generation

Images with motion parallax generated by CG should be displayed, based on the users viewpoint, without delay. In this paper we examine the influence of delay time on images with motion parallax, both subjectively and via the task, by means of a device for 3-D manipulation in virtual space, and we measure the delay time in which the user can easily perceive an image with motion parallax. We also present a method to generate CG image at high speed in the allowable time by selecting from a database of different detailed models one model based on the distance between the viewpoint and object.

Color/texture analysis and synthesis for model-based human image coding

This paper proposes an efficient color/texture analysis and synthesis method for the model-based coding of human images. A shade and shadow elimination scheme is also introduced enhance texture analysis. The input human image is segmented into uniform color regions; color/texture data of each region is analyzed through the first and second order statistics. The synthesis process generates the color/texture of each region from the analyzied data and shading data, which is created from a three dimensional human body model and the new virtual lighting source. The proposed method acquires and encodes the objects’ original color/textures independently of shade and can reconstruct the color/textures while applying any shade effect desired.

Three-dimensional display method without special glasses for virtual space teleconferencing system

In this paper, we propose a new autostereoscopic display system employing an eye-position tracking technique. In this display system, the observable area of stereoscopic images becomes wide and an autostereoscopic display is realized by combining the tracking technique with computer graphic images. The wide 70-inch lenticular screen and HDTV LCD-projector generate more impressive 3-D images than conventional system.

A study of a highly directional loudspeaker system for teleconferencing

音声認識の研究で広く利用されている母音のホルマント周波数帯域に着目し, 指向性の高い狭指向性スピーカと無指向性スピーカとを組合せる会議用音声再生方式を提案し, 本方式の実現に必須である狭指向性スピーカの検討結果について述べる.

An application of packet video to local area network.

高能率映像符号化方式をCSMA/CDアクセス方式のLANに適用する映像パケット伝送について, 情報源の性質の検討およびパケット伝送遅延時間特性についての計算機シミュレーションを行い, その実現可能性を明らかにした.