Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Reissue Patent
1994-07-19
2001-06-12
Britton, Howard (Department: 2613)
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
C348S699000, C375S240150, C386S349000, C386S349000
Reissue Patent
active
RE037222
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a video signal transmitting system, and is suitably applied to a case where moving picture signals are transmitted.
In the so-called video transmitting system, such as a television conference system and television telephone system, video signals representing moving pictures are conventionally sent to a remote destination. The transmission efficiency of significant information is enhanced by efficiently using the transmission capacity of the transmission channel.
For this purpose, the transmitting unit does not send all of the sequential frame pictures but performs a so-called frame dropping processing of the frame pictures such as to remove predetermined frames and then transmits the video signals.
In the receiving unit, motion vectors are received from the transmitting unit in place of the video signals of the removed frames, and the original video signals are reconstructed by interpolating the frame pictures, which have undergone frame dropping processing, by using motion vectors with reference to information in frame pictures before and after them, the motion vectors being transmitted from the transmitting unit in place of the video signals of the frames dropped (Patent Laid-open Publication No. 60 (1985)-28392).
According to this technique, it is theoretically sufficient to transmit information of motion vectors in place of information in frame pictures which have been dropped, the former possessing a smaller amount than the latter. Thus, it is considered that the technique efficiently sends significant information of the video signals.
Accordingly, the more frames that are dropped, the more efficiently video signals are transmitted
When video signals practically undergo high efficiency coding processing and then are recorded on a recording medium, such as a compact disc, errors cannot however be prevented from taking place. Moreover, video signals are also reproduced in reverse mode and random accessed and hence when a large amount of frames are dropped, it is difficult to reproduce video signals with high quality.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of this invention is to provide a video signal transmission system which is capable of efficiently transmitting high quality video signals.
The foregoing object and other objects of the invention have been achieved by the provision of:
a video signal transmitting system, according to a first aspect of the invention, in which digital video signals are divided into groups of predetermined frames; digital video signals of at least one frame of each group of frames are intraframe coded and then transmitted; and digital video signals of at least one frame among the remaining digital video signals of the same group are interframe coded with reference to the intraframe coded digital video signals, together with intraframe coded digital video signals of a subsequent group of frames and are then transmitted;
a video signal transmitting system, according to a second aspect of the invention, in which a motion vector from a predetermined reference frame is detected; and video signals are interframe coded by using the motion vector to transmit the video signals, a motion vector from the reference frame to a first frame which is, according to the present invention, a plurality of frames away from the reference frame, is converted to a motion vector for a one frame interval between the reference frame and the first frame, is optimized, and is then transmitted.
The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings in which like parts are designated by like reference numerals or characters.
REFERENCES:
patent: 4868653 (1989-09-01), Golin
patent: 4985768 (1991-01-01), Sugiyama
patent: 53-082219 (1978-07-01), None
patent: 59-123383 (1984-07-01), None
patent: 62-193383 (1987-08-01), None
patent: 62-213494 (1987-09-01), None
patent: 1-091584 (1989-04-01), None
“An adaptive coding method using front and rear frame prediction for storage media” Kenji Sugiyama et, al. 1989 National Convention Record of the Institute of Television Engineers of Japan; pp. 485-486.
Igarashi Katsuji
Veltman Mark
Yagasaki Yoichi
Yonemitsu Jun
Britton Howard
Frommer William S.
Frommer Lawrence & Haug LLP.
Savit Glenn F.
Sony Corporation
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