US 6,628,801 B2 · Image marking with pixel modification

Abstract

A method and system for embedding signatures within visual images in both digital representation and print or film. A signature is inseparably embedded within the visible image, the signature persisting through image transforms that include resizing as well as conversion to print or film and back to digital form. Signature points are selected from among the pixels of an original image. The pixel values of the signature points and surrounding pixels are adjusted by an amount detectable by a digital scanner. The adjusted signature points form a digital signature which is stored for future identification of subject images derived from the image. In one embodiment, a signature is embedded within an image by locating relative extrema in the continuous space of pixel values and selecting the signature points from among the extrema. Preferably, the signature is redundantly embedded in the image such that any of the redundant representations can be used to identify the signature. Identification of a subject image includes ensuring that the subject image is normalized with respect to the original image or the signed image. Preferably, the normalized subject image is compared with the stored digital signature.

Claims10

Dependent claims

A method of placing a watermark on a digital image, comprising the steps of:

providing a digital original image;
providing a digital watermark image;
and,
producing a watermarked image by superimposing the watermark image on the original image without changing the chromaticities of pixels of the original image as watermarked.

1 more element

Dependencies are inferred from the claim text.

Image marking with pixel modification

Life of this patent

Image marking with pixel modification

Life of this patent

Abstract

Claims10