Strokes Localization by m-Array Decoding and Fast Image Matching
First Claim
1. A method for determining a path of a pen tip within a document, the method comprising:
- (A) decoding extracted bits associated with a captured image to determine location coordinates of the captured image;
(B) in response to (A), if the location coordinates of the captured image cannot be determined by decoding, matching the captured image with image information of the document; and
(C) mapping the path of the pen tip from the location coordinates of the captured image to the location coordinates of the tip of the pen.
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Accused Products
Abstract
Systems and methods that determine a path of a pen tip as the pen tip is moved across a document are described. The document is watermarked with a maze pattern from which encoded position information is determined. A sequence of images is captured by a camera that is located in a pen. The path of the pen tip is determined by decoding the associated maze pattern and by matching the captured images with document images. If the position coordinates of any frame that is associated with a stroke cannot be determined from m-array decoding, the frames are transformed and then matched with an area of a document image. Once the position coordinates of at least one frame is determined, the position coordinates of other frames are determined by matching the frames in a neighboring area.
138 Citations
29 Claims
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1. A method for determining a path of a pen tip within a document, the method comprising:
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(A) decoding extracted bits associated with a captured image to determine location coordinates of the captured image;
(B) in response to (A), if the location coordinates of the captured image cannot be determined by decoding, matching the captured image with image information of the document; and
(C) mapping the path of the pen tip from the location coordinates of the captured image to the location coordinates of the tip of the pen. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. An apparatus that determines a path of a pen tip within a document, comprising:
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a decoding module that decodes extracted bits associated with a captured image;
a matching module that matches the captured image with image information of the document if location coordinates of the captured image cannot be determined by the decoding module; and
a mapping module that maps the path of the pen tip from the location coordinates of the captured image and that provides path information. - View Dependent Claims (25, 26, 27, 28)
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29. A method for determining a path of a pen tip of a pen within a document, the method comprising:
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(A) calibrating the pen in order to obtain a calibration parameter;
(B) analyzing a watermarked document image in order to determine areas where x-y positions cannot be uniquely determined by m-array decoding;
(C) segmenting a maze pattern from an obstruction component of a captured image, wherein the obstruction component comprises document content that occludes the maze pattern;
(D) analyzing the maze pattern to extract bits from the maze pattern of a captured image;
(E) in response to (D), determining a transform that transforms image position coordinates to actual position coordinates, wherein the actual position coordinates identify a location of the pen tip in relation to the document;
(F) decoding the extracted bits associated with the captured image;
(G) in response to (F), if the image location coordinates of the captured image cannot be determined, matching the captured image with image information, comprising;
(i) warping the captured image; and
(ii) matching the warped image with an area of the document, where a corresponding x-y position cannot be uniquely determined by m-array decoding;
(H) determining image location coordinates of other image frames that are associated with a pen stroke, comprising;
(i) matching a corresponding captured image with a neighboring area of the image location coordinates of a previously decoded image; and
(ii) repeating (i) until all image frames of the pen stroke are processed; and
(I) mapping the path of the pen tip from the transform, the calibration parameter, and the image location coordinates.
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Specification