Authentication of physical and electronic media objects using digital watermarks
US7424131B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 2005 |
| Grant date | Sep 9, 2008 |
| Priority date | — |
| Expiry date | Mar 8, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/3284
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Digital watermark methods for encoding auxiliary data into a host signal are used to authenticate physical and electronic objects. One such method computes a content specific message dependent on the host signal, encodes the content specific message into a watermark signal, and embeds the watermark in the host signal such that the watermark signal is substantially imperceptible in the host signal. One specific implementation embeds data representing salient features of the host signal into the watermark. For example, for photo IDs, the method embeds the spatial location of salient features of the photo into the watermark. Another implementation computes a semi-sensitive hash of the host signal, such as a low pass filtering of the signal, and embeds the hash into the watermark. The watermark signal may be content dependent by making the watermark key dependent on some attribute of the signal in which the watermark is embedded. Another approach is to make the watermark key dependent on a user or an attribute of the user. Yet another approach is to use multiple watermark components and multiple watermark detection stages that help identify and screen out invalid watermark signals. Ano…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.