Method and device for processing a sequence of source pictures
US8094286B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 2007 |
| Grant date | Jan 10, 2012 |
| Priority date | — |
| Expiry date | Nov 11, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2005/91392
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention relates to a method for combating the copying of source pictures by means of a camera while they are being displayed, for example using a camcorder in a movie theatre. To this end, it is known, in classical projection systems, to modulate by a carrier wave the brightness of some pixels of the pictures. The frequency of the carrier wave is usually constant and generally half the refresh frequency. The main problem with such systems is that once a pirate has figured out what the modulation frequency is, he can configure his camcorder shutter to filter out this frequency and bypass the anti-camcorder method. According to the invention, the frequency of the carrier is changed at least once throughout the displaying of the sequence pictures or the movie, to defeat all camcorders standards (PAL/NTSC) and shutter configurations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.