Thursdays the PTO publishes new pending patent applications. Both of this week's Spotlight Applications concern aspects of digital watermarking, a form of steganography ("hidden writting"). Assigned to Digimarc, the first application discloses techniques for steganographic encoding and decoding. Apparently assigned to Eastman Kodak, the second application discloses techniques for spectral edge marking for steganography or watermarking.
20130336522, "Steganographic encoding and decoding," assigned to Digimarc.
This patent document relates generally to steganography and digital watermarking. One claim recites, in a watermark encoder, a method of encoding auxiliary information in an image or video comprising: using a programmed electronic processor, computing a change in an attribute of an image or video sample to encode auxiliary information in the image or video; and changing color values of the image or video sample to effect the change in the attribute, in which changes to color values are determined based at least in part on both: i) visibility of the changes, and ii) anticipated watermark detection. Of course, other claims are provided too.
20130335784, "Spectral edge marking for steganography or watermarking," apparently assigned to Eastman Kodak.
A method for providing digital watermarking for text or images that uses spectral edge marking materials (320) printed on a print media (200) to embed hidden data (220). The spectral edge markers (320) have an absorption spectrum at the edge of the human visible spectrum, either at the UV edge or IR edge, which provides an optical density that is generally imperceptible to humans, but which can be detected by an image capture device (250). The crosstalk of visible optical absorption provided by these materials is largely masked by the presence of visible colorant(s) (340), with only small color differences between areas with and without the spectral edge markers (320). The image capture device (250) has a visible spectral response that extends into a spectral region just outside the visible spectrum where the spectral edge marker absorption occurs, and can be operated to detect the hidden data.