Authenticating media signals by adjusting frequency characteristics to reference values
US7346776B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 6, 2000 |
| Grant date | Mar 18, 2008 |
| Priority date | — |
| Expiry date | Dec 8, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L69/329
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of authenticating a media signal and related software, systems and applications. The method transforms at least a portion of the media signal into a set of frequency coefficients in a frequency domain. For example, it applies a Fast Fourier Transform (FFT) or other frequency transform to blocks of a media signal, such as an image, audio or video signal. It adjusts a relationship between selected frequency coefficients to a reference value. This adjustment is selected so that an alteration to be detected, such as a re-sampling operation or digital to analog—analog to digital conversion, alters the relationship. To detect the alteration, a detector computes the relationship in a potentially corrupted version of the signal. It then compares the result with a threshold value to detect whether the alteration has occurred.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.