Methods for marking images
AssigneeDigimarc Corporation
InventorGeoffrey B. Rhoads
Life of this patent
Estimating the term…
Abstract
An image is marked by making slight changes to pixel values. These changes are essentially imperceptible on human scrutiny, but detectable by computer analysis. Such markings have applications in identifying ownership of images (including video), and also in device control (e.g., triggering a “do not copy” response in suitably configured hardware and software systems).
Claims15
A method for imparting a watermark onto a digitized image comprising the steps of:
- providing said digitized image comprised of a plurality of pixels, wherein each of said pixels includes brightness data that represents a brightness of at least one color;
- and
- adjusting said brightness data associated with at least one of said pixels by a predetermined brightness value, wherein said brightness value has a relationship with a number taken from a random number sequence.
A method for generating a watermarked image wherein a watermark is imparted onto a digitized image having a plurality of original elements having original brightnesses, said method comprising the steps of:
- providing a digitized watermarking plane comprising a plurality of watermarking elements, each having a watermark brightness value and having one-to-one correspondence with said original elements;
- and
- producing a watermarked image by adjusting said original brightness of each of said original elements by said brightness values of a corresponding one of said watermark elements wherein said watermark is invisible.
A method for imparting a watermark onto a digitized image comprising:
- providing said digitized image comprised of a plurality of pixels, wherein each of said pixels includes brightness data that represents a brightness of at least one color;
- and
- adjusting said brightness data associated with at least one of said pixels by a predetermined brightness value in a predetermined range,
- wherein said brightness value has a relationship with a number taken from a random number sequence, said relationship is a linear mapping to provide a desired modulation strength.
A method for imparting a watermark onto a digitized image comprising:
- providing said digitized image comprised of a plurality of pixels, wherein each of said pixels includes brightness data that represents a brightness of at least one color;
- and adjusting said brightness data associated with at least one of said pixels by a predetermined brightness value,
- wherein said brightness value has a relationship with a number taken from a random number sequence, said relationship is a linear mapping to provide a desired modulation strength, said sequence is formed from a plurality of robust watermarking parameters, and said parameters comprise a cryptographic key and an initial value of said random number generator.
Dependencies are inferred from the claim text.