Digital data encoding in video signals using data modulated carrier signals at non-peaks in video spectra
US5663766A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 25, 1996 |
| Grant date | Sep 2, 1997 |
| Priority date | — |
| Expiry date | Jan 25, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/08
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Digital information is encoded in the video portion of a television signal such that "n" (n is an integer) bits of the digital information are carried by each successive frame in a group of frames. The digital information is encoded by modulating a carrier signal, using, for example, either amplitude shift keying (ASK) or frequency shift keying (FSK), and the modulated carrier is then added to the video signal selectively, only in portions of the television program that (a) are not likely to be perceptible by a viewer, and (b) are of sufficient intensity to transmit the data. The video signal including the encoded digital data, may be transmitted, in real time, to a television receiver, or recorded for later playback. In either event, at a receiver, when the video signal containing the encoded information is displayed on a screen, the image is sensed or "viewed" by a photo detector, the output of which is applied to a band pass filter having a center frequency that corresponds to the oscillator frequency(s) in the encoder. The filter output is thresholded or FM detected, so that the receiver can recover the encoded data. By appropriately including checks bits and synchronization pa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.