Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1989-10-13
1991-12-24
Kostak, Victor R.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358142, H04N 708
Patent
active
050757733
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to the transmission of additional data in the active picture period of video transmissions for example such as broadcast television transmission.
Digitally assisted television (DATV) has been proposed which uses additional data transmitted with a video signal to enhance the display at the receiver and thereby produce, for example, a high definition television (HDTV) picture or some other enhanced display.
It is proposed that HDTV receivers will typically operate with a larger aspect ratio, namely the ratio of picture width to picture height, than that used with conventional receivers operating, for example, on 625 lines. Since conventional receivers are not compatible with a full bandwidth HDTV signal a method of transmitting signals which can be received on both types of receiver is needed.
A system for use with both HDTV receivers and conventional receivers is described in U.S. Pat. No. 4,613,903. This uses a high resolution TV camera to provide two transmission signals. The first of these is compatible with a conventional receiver. This signal includes the sum average of two of the HDTV fields in a first field and the remaining HDTV field in a second field. The second signal contains the remaining HDTV information. An HDTV receiver uses both transmitted signals to reconstruct an HDTV signal.
U.S. Pat. No. 4,672,425 proposes transmitting data in the active picture period of a conventional transmission and using this data to produce an extended aspect ratio picture on a non-conventional receiver. However, since the data is in the active picture period it is visible on the conventional receiver.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a method of transmitting extended aspect ratio pictures in a video signal comprising the steps of, providing a video signal in which picture information occupies a smaller number of lines than the number required to fill the visible area of a conventional receiver, inserting additional data into at least some of the lines not used for picture information, the data being at a sufficiently low level to be substantially invisible when viewed on a conventional receiver, and transmitting the picture information and data as a conventional video signal.
According to another aspect of the present invention there is provided a method of transmitting additional data in a video signal comprising the steps of providing a video signal in which picture information occupies less than the whole visible area of a conventional receiver, inserting additional data into at least part of the area not used for picture information, the data being at a sufficiently low level to be substantially invisible when viewed on a conventional receiver, and transmitting the picture information and data as a conventional video signal.
The present invention also provides apparatus to transmit additional data in a video signal comprising means to provide a first video signal with a first number of lines, means to convert the signal to a second video signal on a reduced number of lines together with data relating to the difference between the two signals, first storage means coupled to a second video signal output of the conversion means, second storage means coupled to a data output of the conversion means, combining means coupled to the outputs of the first and second storage means and with an output coupled to the input of a transmitter means, to combine the stored video and data, the data being at a sufficiently low level to be substantially invisible when viewed on a conventional receiver, and control means coupled to the first and second storage means and having a timing information input, to determine whether video signal information from the first storage means or data from the second storage means is available at the combining means inputs.
Another aspect of the invention provides apparatus to receive a video signal containing additional data within the active picture area, the data being at a suffic
REFERENCES:
patent: 4394690 (1983-07-01), Kobayashi
patent: 4556906 (1985-12-01), Dischert
patent: 4613903 (1986-09-01), Nadan
patent: 4672425 (1987-06-01), Marie et al.
patent: 4855827 (1989-08-01), Best
patent: 4931855 (1990-06-01), Salvadorini
patent: 4959717 (1990-09-01), Faroudja
"6-MHz Single-Channel HDTV Systems", Schrieber; HDTV Symposium at Ottawa, Oct. '87, pp. 1-7.
Pullen Ian R.
Sandbank Charles P.
British Broadcasting Corporation
Kostak Victor R.
O'Connell Robert F.
LandOfFree
Data transmission in active picture period does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Data transmission in active picture period, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Data transmission in active picture period will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-48294