Apparatus and method for embedding electronic watermark
AssigneeOki Electric Industry Co., Ltd.
InventorsTakashi Hashimoto, Kurato Maeno
Life of this patent
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Abstract
An electronic watermark embedding apparatus for embedding watermark information as digital information into a document image includes a background eliminating unit that determines whether pixels on an input image are pixels composing a background image and eliminates the pixels determined as the pixels composing the background image from the input image, and a watermark embedding unit that embeds a watermark into a background eliminated image from which the background is eliminated by the background eliminating unit so as to form a watermark image. A readable watermark can be embedded into a multi-valued image including a halftone/gradation portion on the background of the input image.
Claims19
An electronic watermark embedding apparatus that embeds watermark information as digital information into a document image, the apparatus comprising:
- a background determining unit that determines whether pixels on the document image are pixels composing a background image;
- a background eliminating unit that eliminates the pixels determined as the pixels composing the background image by the background determining unit from the document image;
- and
- a watermark embedding unit that embeds a watermark into a background eliminated image from which the background is eliminated by the background eliminating unit.
An electronic watermark embedding apparatus that embeds watermark information as digital information into a document image, the apparatus comprising:
- a background determining unit that determines pixels on the document image are pixels composing a background image;
- a background separating unit that separates the document image into a foreground image and the background image on the basis of the determined result of the background determining unit;
- and
- a watermark embedding unit that embeds a watermark into the foreground image output by the background separating unit,
- wherein the watermark embedding unit changes concentration or density of the watermark to be embedded into the foreground image according to contents of the background image.
An electronic watermark embedding method for embedding watermark information as digital information into a document image, comprising the steps of:
- determining whether pixels on the document image are pixels composing a background image;
- eliminating the pixels determined as the pixels composing the background image from the document image;
- and
- embedding a watermark into a region of the eliminated background image.
An electronic watermark embedding method for embedding watermark information as digital information into a document image, the method comprising the steps of:
- determining whether pixels on the document image are pixels composing a background image;
- separating the document image into a foreground image and the background image;
- and
- changing concentration or density of the watermark according to contents of the background image so as to embed the watermark into the foreground image.
Dependencies are inferred from the claim text.