Digital watermarking
AssigneeOptimark, L.L.C.
InventorsOscar Moreno De Ayala, Anatol Zygmunt Tirkel
Life of this patent
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Abstract
A device for applying or extracting a digital watermark of two or more dimensions and a method of applying or extracting the digital watermark. The digital watermark is generated by adding a suitable number of watermarking arrays. Each watermarking array is constructed by convolving a multi-periodic shift array having a correlation bounded by a constant (two or greater) with a balanced periodic substitution sequence.
Claims23
A device for applying a digital watermark to an image, the device comprising:
- a storage element storing programme steps for generating a watermark of two or more dimensions;
- an image sensor that acquires at least one image that is a digital image or converted to a digital image;
- and
- a processor that combines the at least one image or a sequence of the at least one images and the watermark;
- wherein the watermark is generated by convolving a multi-periodic shift array of dimension two or greater with a balanced periodic substitution sequence or array;
- and wherein the multi-periodic shift array is derived from a polynomial of degree two or greater.
A method of applying a digital watermark to at least one digital image including the steps of:
- capturing the at least one digital image;
- generating a watermark by convolving a multi-periodic shift array of dimension two or greater with a balanced periodic substitution sequence or array, wherein the multi-periodic shift array is derived from a polynomial of degree two or greater;
- and
- encoding the at least one digital image with the watermark.
A method of identifying a watermarked digital image including the steps of:
- receiving a digital image;
- and
- detecting if the image contains a watermark by performing a cross-correlation with a set of reference arrays;
- wherein the reference arrays are formed by convolving a multi-periodic shift array of dimension two or greater with a balanced periodic substitution sequence or array;
- and wherein the multi-periodic shift array is derived from a polynomial of degree two or greater.
Dependencies are inferred from the claim text.