US 6,246,777 B1 · Compression-tolerant watermarking scheme for image authentication

Abstract

A verification system for still images that embeds a watermark so that no visual artifacts are created in the images and thus maintains the visual quality of the image. The algorithm embeds information in an uncompressed image so as to later detect the alteration of the image, as well as the location of the alteration. The embedding of information into a source image is based on a defined mapping process. An image plane consists of macroblocks, which are themselves comprised of microblocks. A code is embedded corresponding to the value of this image property in each macroblock. The specific sequence of microblocks used for embedding this information in the watermarking image plane is a unique function of this property for the corresponding set of microblocks in the indexing image plane. This information can be later decoded from the stamped image. The watermark is embedded by combining the pixel values of the image with the watermark. The watermark is altered if the image is altered.

Claims27

Dependent claims

A method for embedding a watermark onto a digitized image, comprising the steps of:

calculating a secret key used for embedding the watermark;
splitting the digitized image into constituent planes;
splitting each constituent plane into a plurality of microblocks based upon the secret key, the microblocks having a shape of a rectilinear polygon;
grouping the microblocks into a plurality of macroblocks based upon the secret key, the macroblocks being a group of microblocks;
and
watermarking each macroblock while diffusing the error.

3 more elements

A computer program product comprising a computer usable medium having computer readable program code embodied in the medium for embedding a watermark onto a digitized image, the computer program product having:

first computer program code for calculating a secret key used for embedding the watermark;
second computer program code for splitting the digitized image into constituent planes;
third computer program code for splitting each constituent plane into a plurality of microblocks based upon the secret key, the microblocks having a shape of a rectilinear polygon;
fourth computer program code for grouping the microblocks into a plurality of macroblocks based upon the secret key, the macroblocks being a group of microblocks;
and
fifth computer program code for watermarking each macroblock while diffusing the error.

3 more elements

Dependencies are inferred from the claim text.

Compression-tolerant watermarking scheme for image authentication

Life of this patent

Compression-tolerant watermarking scheme for image authentication

Life of this patent

Abstract

Claims27