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AssigneeCanon Kabushiki Kaisha
InventorJun Tamaru
Estimating the term…
This invention provides a digital watermark embedding apparatus for a document, which can eliminate unnaturalness that may be experienced upon laying out characters in a document when watermark information is embedded, while maintaining the robustness of a document itself and the information size to be embedded of a digital watermark. A document image is input from an image input unit (11), and watermark information is input from a watermark information input unit (15). A region division unit (12) divides the document image into regions, and a circumscribing rectangle extraction unit (13) sets circumscribing rectangles for characters and extracts them as character images. A punctuation mark determination unit (14) determines a punctuation mark from the character image. A watermark information embedding unit (16) embeds watermark information by digital watermarking that shifts character images other than the character image determined to be a punctuation mark.
A digital watermark embedding apparatus for a document, which comprises image input means for inputting a document image obtained by converting a document into digital data, character extraction means for extracting character images included in the document image, watermark information input means for inputting watermark information, and watermark information embedding means for embedding the watermark information by digital watermarking that exploits spaces between the extracted character images, further comprising:
A digital watermark extraction apparatus for a document, which comprises image input means for inputting a document in which watermark information is embedded by digital watermarking as a digital document image, character extraction means for extracting character images included in the document image, and watermark information extraction means for extracting the embedded watermark information on the basis of spaces between the extracted character images, further comprising:
A method of controlling a digital watermark embedding apparatus for a document, which embeds predetermined watermark information in a document image obtained by inputting a document as a digital image, by digital watermarking that exploits spaces between character images, comprising:
A method of controlling a digital watermark extraction apparatus for a document, which extracts predetermined watermark information from a document image embedded with the predetermined watermark information, comprising:
A computer program for controlling a digital watermark embedding apparatus for a document, which embeds predetermined watermark information in a document image obtained by inputting a document as a digital image, by digital watermarking that exploits spaces between character images, comprising:
A computer program for controlling a digital watermark extraction apparatus for a document, which extracts predetermined watermark information from a document image embedded with the predetermined watermark information, comprising:
Dependencies are inferred from the claim text.