Watermark information embedment device and watermark information detection device
First Claim
1. A watermark information embedment device comprising:
- a document image formation portion forming a document image based on document data on a page by page basis;
a watermark image formation portion forming a watermark image; and
a watermarked document image composition portion forming a watermarked document image by putting said document image on said watermark image;
wherein said watermark image is made up of a plurality of different sorts of dot patterns regularly arranged according to a certain rule, and at least one sort of said dot patterns is provided with secret information indicative of a specific confidential matter,wherein the dot patterns of each sort have a dot arrangement that provides a wave propagation direction and a wavelength, at least one of said wave propagation direction and said wavelength being different from each of the sorts,wherein each dot pattern of the same sort is given the same symbol, andwherein said secret is represented by combining said dot patterns.
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Accused Products
Abstract
There are disclosed a watermark information embedment device capable of accurately embedding secret information, and a watermark information detection device. In the watermark information embedment device, there are prepared a plurality of different sorts of dot patterns in which the wave propagation direction and the wave length are changed depending on the dot arrangement. Each dot pattern of the same sort is given the same symbol, and the secret information is represented by combining these dot patterns. In the watermark information detection device, there are provided 2-dimensional wavelet filters having the same wave propagation direction and the wave length as the different sorts of dot patterns. There is computed convolution between an arbitrary region in the watermarked image and plural 2-dimensional wavelet filters, and it is judged that the dot pattern corresponding to a particular one of the 2-dimensional wavelet filters is embedded in the region where the computed convolution indicates a maximum value.
66 Citations
11 Claims
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1. A watermark information embedment device comprising:
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a document image formation portion forming a document image based on document data on a page by page basis; a watermark image formation portion forming a watermark image; and a watermarked document image composition portion forming a watermarked document image by putting said document image on said watermark image; wherein said watermark image is made up of a plurality of different sorts of dot patterns regularly arranged according to a certain rule, and at least one sort of said dot patterns is provided with secret information indicative of a specific confidential matter, wherein the dot patterns of each sort have a dot arrangement that provides a wave propagation direction and a wavelength, at least one of said wave propagation direction and said wavelength being different from each of the sorts, wherein each dot pattern of the same sort is given the same symbol, and wherein said secret is represented by combining said dot patterns. - View Dependent Claims (2, 4, 5)
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3. A watermark information embedment device comprising:
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a document image formation portion forming a document image based on document data on a page by page basis; a watermark image formation portion forming a watermark image; and a watermarked document image composition portion forming a watermarked document image by putting said document image on said watermark image; wherein said watermark image is made up of a plurality of different sorts of dot patterns regularly arranged according to a certain rule, and at least one sort of said dot patterns is provided with secret information indicative of a specific confidential matter, wherein the dot patterns of each sort have a wave propagation direction and a wave length, at least one of said wave propagation direction and said wavelength being different for each of said sorts, wherein one combination of at least two sorts of said dot patterns is given one symbol, and wherein said secret information is represented by further combining combinations of said dot patterns with another one.
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6. A watermark information detection device comprising:
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a watermark detection portion for detecting a watermark image from a watermarked document image formed by putting a document image on a watermark image in which a plurality of sorts of dot patterns are embedded, wherein said watermark detection portion is provided with at least one filter for extracting the same plural sorts of dot patterns as said watermark image, and said watermark image is extracted by examining the matching between said at least one filter and said watermarked document image, wherein the dot patterns of each sort have a wave propagation direction and a wavelength, at least one of said wave propagation direction and said wavelength being different for each of the sorts, wherein each dot pattern of the same sort is given the same symbol, wherein said secret information is represented by combining said dot patterns, and wherein said at least one filter comprises a plurality of 2-dimensional wavelet filters of which the number is equal to the number of sorts of dot patterns. - View Dependent Claims (7, 8, 9, 10, 11)
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Specification