Robust automatic page size detection algorithm for scan application
First Claim
Patent Images
1. A method of automatically detecting a page size for a digital scanning operation, the method comprising:
- establishing vertical and horizontal limits of an image area containing image content features of a pre-scanned image by analyzing edge and gray level attributes of the pre-scanned image, wherein establishing of the image area limits comprises;
apportioning the pre-scanned image into a plurality of overlapping localized areas,detecting edge and gray level attributes for each overlapping localized area, andqualifying the detected edge and/or gray level attributes to generate the image area;
detecting vertical page edge information of the image area; and
detecting horizontal page edge information of the image area,wherein the vertical and horizontal page edge information define the page size for the pre-scanned image.
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Abstract
The present invention discloses a method of automatically detecting a page size for a digital scanning operation. The method includes establishing vertical and horizontal limits of an image area containing image content features of a pre-scanned image, detecting vertical page edge information of the image area, and detecting horizontal page edge information of the image area, such that the vertical and horizontal page edge information define the page size for the pre-scanned image.
15 Citations
12 Claims
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1. A method of automatically detecting a page size for a digital scanning operation, the method comprising:
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establishing vertical and horizontal limits of an image area containing image content features of a pre-scanned image by analyzing edge and gray level attributes of the pre-scanned image, wherein establishing of the image area limits comprises; apportioning the pre-scanned image into a plurality of overlapping localized areas, detecting edge and gray level attributes for each overlapping localized area, and qualifying the detected edge and/or gray level attributes to generate the image area; detecting vertical page edge information of the image area; and detecting horizontal page edge information of the image area, wherein the vertical and horizontal page edge information define the page size for the pre-scanned image. - View Dependent Claims (2)
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3. A method of automatically detecting a page size for a digital scanning operation, the method comprising:
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establishing vertical and horizontal limits of an image area containing image content features of a pre-scanned image by analyzing edge and gray level attributes of the pre-scanned image, wherein establishing of the image area limits comprises; apportioning the pre-scanned image into a plurality of localized areas, detecting edge and gray level attributes for each localized area, and qualifying the detected edge and/or gray level attributes to generate the image area; detecting vertical page edge information of the image area; and detecting horizontal page edge information of the image area, wherein the vertical and horizontal page edge information define the page size for the pre-scanned image, wherein the qualification of the detected edge and/or gray level attributes comprises qualifying an attribute as an image feature corresponding to a particular localized area if at least another localized area adjacent to the particular localized area also includes a qualified image feature. - View Dependent Claims (4)
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5. A method of automatically detecting a page size for a digital scanning operation, the method comprising:
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establishing vertical and horizontal limits of an image area containing image content features of a pre-scanned image by analyzing edge and gray level attributes of the pre-scanned image; detecting vertical page edge information of the image area; detecting horizontal page edge information of the image area, wherein the vertical and horizontal page edge information define the page size for the pre-scanned image; filtering the image area along a horizontal direction to produce a smoothed image area, detecting horizontal edges in the smoothed image area to generate a horizontal edge point map, dividing the horizontal edge point map into overlapping horizontal bands; and determining whether the edge points in the bands exceed a threshold, wherein the vertical page edge information is set to the first band from the bottom that exceeds the threshold and the vertical page edge information is set to the vertical limit of the image area when no band exceeds the threshold. - View Dependent Claims (6)
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7. A method of scanning a document comprising:
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generating a reduced resolution image of the document; establishing vertical and horizontal limits of an image area containing image content features of the reduced resolution image by analyzing edge and gray level attributes, wherein establishing of the image area limits comprises; apportioning the reduced resolution image into a plurality of overlapping localized areas, detecting edge and gray level attributes for each overlapping localized area, and qualifying the detected edge and/or gray level attributes to generate the image area; detecting vertical page edge information of the image area; detecting horizontal page edge information of the image area; scanning the document with a corresponding page size based on the detected vertical and horizontal page edge information. - View Dependent Claims (8)
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9. A method of scanning a document, comprising:
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generating a reduced resolution image of the document; establishing vertical and horizontal limits of an image area containing image content features of the reduced resolution image by analyzing edge and gray level attributes, wherein establishing of the image area limits comprises; apportioning the reduced resolution image into a plurality of localized areas, detecting edge and gray level attributes for each localized area, and qualifying the detected edge and/or gray level attributes to generate the image area; detecting vertical page edge information of the image area; detecting horizontal page edge information of the image area; scanning the document with a corresponding page size based on the detected vertical and horizontal page edge information, wherein the qualification of the detected edge and/or gray level attributes comprises qualifying an attribute as an image feature corresponding to a particular localized area if at least another localized area adjacent to the particular localized area also includes a qualified image feature. - View Dependent Claims (10)
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11. A method of scanning a document, comprising:
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generating a reduced resolution image of the document; establishing vertical and horizontal limits of an image area containing image content features of the reduced resolution image by analyzing edge and gray level attributes; detecting vertical page edge information of the image area; detecting horizontal page edge information of the image area; scanning the document with a corresponding page size based on the detected vertical and horizontal page edge information; filtering the image area along a horizontal direction to produce a smoothed image area, detecting horizontal edges in the smoothed image area to generate a horizontal edge point map, dividing the horizontal edge point map into overlapping horizontal bands; and determining whether the edge points in the bands exceed a threshold, wherein the vertical page edge information is set to the first band from the bottom that exceeds the threshold and the vertical page edge information is set to the vertical limit of the image area when no band exceeds the threshold. - View Dependent Claims (12)
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Specification