Hitachi, Ltd.

Yuuji Kimura

Takahiro Yamada

Itaru Nonomura

Shinichi Hashimoto

Kazuaki Tanaka

Kazuhiro Fujisaki

Shin-ichi Hashimoto

Tetsuya Kawahara

In a data transfer system, a transmission terminal is provided with a transmission unit and a divisional transmission unit. A server station is provided with mailboxes, a transmission/reception management unit, a divisional reception unit and a divisional transmission unit. A reception terminal is provided with a reception,/reconstruction unit and a divisional reception unit. In the transmission of video mail from the transmission unit (or from the transmission/reception management unit) to the transmission/reception management unit (or to the reception/reconstruction unit), audio and a frame (still picture) representative of a motion picture, among data contained in the video mail, are first sent by an ordinary method. Video data in the video mail are thereafter transmitted from the divisional transmission unit to the divisional reception unit by a plurality of separate operations. Such a construction can realize data transfer of the video mail which relieves traffic in multimedia data transmission and also copes with the urgency of the mail while making the best use of an existing network.

Video mail system capable of transferring large quantities of data

An image coding system and method thereof previously defines a plurality of combinations into a table. The table includes candidate values for quantizing steps and candidate values for upper limit values of space frequencies in correspondence with an image code size. The frequencies are coded into the pattern table on the basis of an error between the required code size, which is decided by the system performance, and required images. The generated code size is taken at the time of prediction coding between motion compensation frames. One combination of a quantizing step and upper limit values of space frequency are selected. The combination is coded from the candidate values depending on the image attribute and codes conforming to an international standard. The combinations are generated at a satisfactory coding efficiency. The coding efficiency is achieved by controlling the coding parameters depending on the image attribute and generated code size.

Image coding system with adaptive spatial frequency and quantization

A data transfer system for data transfer between a plurality of information processors connected to a communication line comprises at least one specified sending information processor and one specified receiving information processor. The sending information processor determines the block size in which original data to be sent to the receiving information processor is to be divided and the transfer time interval at which data blocks are to be transferred, divides the original data to be sent into data blocks of the determined block size, and sends the data blocks to the receiving information processor at the determined transfer time interval. The receiving information processor receives and reconstructs the data blocks sent thereto to obtain the original data.

Data transfer system

Growing community of inventors

Yokohama, Japan

Yuuji Kimura