Recognition and tracking using invisible junctions
First Claim
1. A method for recognizing and tracking a point and a viewing region of an electronic document using invisible junction features, the method comprising:
- receiving an input image;
applying a distance transformation to generate invisible junctions within the input image;
determining the point at one of the invisible junctions;
retrieving a previous recognition result;
processing the input image using the previous recognition result to identify the point and the viewing region within the electronic document page; and
identifying an electronic document page corresponding to the input image based on the invisible junctions, the previous recognition result and the point.
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Abstract
The present invention uses invisible junctions which are a set of local features unique to every page of the electronic document to match the captured image to a part of an electronic document. The present invention includes: an image capture device, a feature extraction and recognition system and database. When an electronic document is printed, the feature extraction and recognition system captures an image of the document page. The features in the captured image are then extracted, indexed and stored in the database. Given a query image, usually a small patch of some document page captured by a low resolution image capture device, the features in the query image are extracted and compared against those stored in the database to identify the query image. The present invention also includes methods for recognizing and tracking the viewing region and look at point corresponding to the input query image. This information is combined with a rendering of the original input document to generate a new graphical user interface to the user. This user interface can be displayed on a conventional browser or even on the display of an image capture device.
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Citations
28 Claims
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1. A method for recognizing and tracking a point and a viewing region of an electronic document using invisible junction features, the method comprising:
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receiving an input image; applying a distance transformation to generate invisible junctions within the input image; determining the point at one of the invisible junctions; retrieving a previous recognition result; processing the input image using the previous recognition result to identify the point and the viewing region within the electronic document page; and identifying an electronic document page corresponding to the input image based on the invisible junctions, the previous recognition result and the point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A system for recognizing and tracking a point and a viewing region of an electronic document using invisible junction features, the system comprising:
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a processor; a feature extraction unit stored on a memory and executed by the processor, the feature extraction unit for receiving an input image, applying a distance transformation to generate invisible junctions within the input image and determining the point at one of the invisible junctions; a recognizer unit coupled to the feature extraction unit, the recognizer unit for retrieving a previous recognition result; a tracker coupled to the recognizer unit, the tracker for processing the input image using the previous recognition result to identify the point and the viewing region within the electronic document page; and a feature retrieval unit coupled to the tracker, the feature retrieval unit for identifying an electronic document page corresponding to the input image based on the invisible junctions, the previous recognition result and the point. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification