Digital (on screen) monochromatic watermark
AssigneeXerox Corporation
InventorEdward N. Chapman
Life of this patent
Estimating the term…
Abstract
Methods and systems for rendering a watermark, can involve creating a digital watermark by applying grayscale inversion and contrast reduction to a document, resulting in a visually distinguishable pattern and rendering a digital watermark on the document in a manner that allows verification at different viewing angles. The digital watermark can be created using a digital swatch sheet of multiple gray values. The document can be viewed varying angles to verify the validity of the document based on the visibility and characteristics of the digital watermark. The digital watermark may be modified on predetermined parameters to facilitate enhanced security against fraud.
Claims20
A method for rendering a watermark, comprising:
- creating a digital watermark by applying grayscale inversion and contrast reduction to a document, resulting in a visually distinguishable pattern, wherein creating the digital watermark includes creating a digital swatch sheet of multiple gray values;
- and
- rendering a digital watermark on the document in a manner that allows verification at different viewing angles.
A method for rendering a digital watermark, comprising:
- in a first viewing mode, viewing a digital swatch sheet on a screen and verifying that a predefined text is darker than a background, wherein the digital swatch sheet is initially configured with multiple gray values;
- in a second viewing mode, viewing the digital swatch sheet on the screen and verifying that a second predefined text is lighter than the background;
- at a second angle, verifying that the inverse of the first and second viewing modes is true;
- at a third angle, verifying that the digital watermark virtually disappears with respect to at least two gray swatches on the digital swatch sheet, wherein the at least two gray swatches are based on the multiple gray values.
A system for rendering a digital watermark, comprising:
- at least one processor and a memory, the memory storing instructions to cause the at least one processor to perform:
- in a first viewing mode, viewing a digital swatch sheet on a screen and verifying that a predefined text is darker than a background, wherein the digital swatch sheet is initially configured with multiple gray values;
- in a second viewing mode, viewing the digital swatch sheet on the screen and verifying that a second predefined text is lighter than the background;
- at a second angle, verifying that the inverse of the first and second viewing modes is true;
- and
- at a third angle, verifying that the digital watermark virtually disappears with respect to at least two gray swatches on the digital swatch sheet, wherein the at least two gray swatches are based on the multiple gray values.
Dependencies are inferred from the claim text.