Method for detecting a document boundary
First Claim
1. A method for detecting a document boundary in a captured digital image of a document, the method implemented at least in part by a data processing system and comprising:
- receiving a color digital image captured using a digital imaging system that depicts a hardcopy document on a background, wherein the color digital image includes image data for a plurality of color channels;
for each of the color channels analyzing the image data to determine a corresponding busyness metric, the busyness metric representing a complexity level of the image data, wherein the determination of the busyness metric includes determining a compressibility metric for the image data;
selecting the color channel having a lowest busyness level;
analyzing the image data for the selected color channel to detect the document boundary of the depicted hardcopy document; and
storing an indication of the detected document boundary in a processor-accessible memory.
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Accused Products
Abstract
A method for detecting a document boundary in a captured digital image depicting a hardcopy document on a background. Each color channel of the captured digital image is analyzed to determine a corresponding busyness metric representing a complexity level of the image data. The color channel having a lowest busyness level is selected and analyzed to detect a document boundary of the depicted hardcopy document. The detected document boundary can be used to perform a perspective correction process to determine a corrected digital image where the depicted document has a substantially rectangular boundary.
16 Citations
20 Claims
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1. A method for detecting a document boundary in a captured digital image of a document, the method implemented at least in part by a data processing system and comprising:
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receiving a color digital image captured using a digital imaging system that depicts a hardcopy document on a background, wherein the color digital image includes image data for a plurality of color channels; for each of the color channels analyzing the image data to determine a corresponding busyness metric, the busyness metric representing a complexity level of the image data, wherein the determination of the busyness metric includes determining a compressibility metric for the image data; selecting the color channel having a lowest busyness level; analyzing the image data for the selected color channel to detect the document boundary of the depicted hardcopy document; and storing an indication of the detected document boundary in a processor-accessible memory. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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7. A method for detecting a document boundary in a captured digital image of a document, the method implemented at least in part by a data processing system and comprising:
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receiving a color digital image captured using a digital imaging system that depicts a hardcopy document on a background, wherein the color digital image includes image data for a plurality of color channels; for each of the color channels analyzing the image data to determine a corresponding busyness metric, the busyness metric representing a complexity level of the image data; selecting the color channel having a lowest busyness level; analyzing the image data for the selected color channel to detect the document boundary of the depicted hardcopy document; and storing an indication of the detected document boundary in a processor-accessible memory; and applying a perspective correction process to the captured color digital image based on the detected document boundary to determine a corrected digital image where the depicted document has a substantially rectangular boundary. - View Dependent Claims (20)
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18. A document imaging system for capturing a digital image of a document, comprising:
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an image capture system adapted to capture a color digital image of a hardcopy document on a background, wherein the captured color digital image includes image data for a plurality of color channels; a data processing system; and a memory system communicatively connected to the data processing system and storing instructions configured to cause the data processing system to implement a method for correcting perspective distortion in the captured color digital image, wherein the method includes; transforming the captured color digital image to an analysis color space having a plurality of analysis color channels; for each of the analysis color channels analyzing the image data to determine a corresponding busyness metric, the busyness metric representing a complexity level of the image data; selecting the analysis color channel having a lowest busyness level; analyzing the image data for the selected analysis color channel to detect the document boundary of the depicted document; applying a perspective correction process to the captured color digital image based on the detected document boundary to determine a corrected digital image where the depicted document has a substantially rectangular boundary; and storing the corrected digital image in a processor-accessible memory.
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19. A method for detecting a document boundary in a captured digital image of a document, the method implemented at least in part by a data processing system and comprising:
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receiving a color digital image captured using a digital imaging system that depicts a hardcopy document on a background, wherein the color digital image includes image data for a plurality of color channels; for each of the color channels analyzing the image data to determine a corresponding busyness metric, the busyness metric representing a complexity level of the image data, wherein the determination of the busyness metric includes determining an image entropy metric for the image data; selecting the color channel having a lowest busyness level; analyzing the image data for the selected color channel to detect the document boundary of the depicted hardcopy document; and storing an indication of the detected document boundary in a processor-accessible memory.
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Specification