Back to results
US 6,608,919 B1Granted
Method and apparatus for encoding paper with information
AssigneeDigimarc Corporation
InventorAdnan M. Alattar
Life of this patent
Estimating the term…
Abstract
Paper is textured with a pattern that yields a known signature signal when transformed to the frequency domain. This signature can be used for various purposes, including determining the angular orientation of the paper when scanned, conveying a plural-bit digital watermark, and for simple document recognition purposes (e.g., photocopiers that refuse to reproduce banknotes). The texturing can be effected during the paper-making process, e.g., by shaping the surface of a de-watering element accordingly.
Claims12
A method of determining a transformation of a paper document including:
- optically scanning the paper document to generate scan data;
- transforming the scan data to a frequency domain;
- identifying frequency components in the transformed scan data corresponding to texture resulting from the paper's manufacture;
- and
- determining from said frequency components one or more possible transformations of the scanned documents from a reference state.
2 more elements
A method including:
- optically scanning a paper document to generate scan data;
- transforming the scan data to a frequency domain;
- identifying frequency components in the transformed scan data corresponding to texture resulting from the paper's manufacture;
- and
- interpreting said identified frequency components to yield payload data including at least a registration indicator.
2 more elements
A paper-making process including:
- defining a frequency-domain signal, wherein the frequency-domain signal comprises an orientation component;
- inverse transforming the frequency-domain signal to yield a two-dimensional pattern in the spatial domain;
- shaping an element of the paper-making apparatus in accordance with said spatial domain pattern;
- and
- imparting said pattern to a paper surface, wherein the orientation component provides an orientation reference for paper made according to said paper-making process.
2 more elements
Dependencies are inferred from the claim text.