Identifying embedded data in an image
First Claim
1. A method for determining a robust average intensity of pixels from a portion of an image comprising pixels, the method comprising:
- computing a cumulative density function based upon an intensity histogram of the pixels from the portion of the image;
using the cumulative density function to identify pixels to exclude;
calculating a robust average intensity using at least some of the pixels that were not excluded;
using the robust average intensity to determine an embed pattern in a candidate embedding site comprising pixels; and
using the embed pattern to extract a data value from the candidate embedding site.
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Accused Products
Abstract
Disclosed are embodiments of systems and methods for embedding and/or extracting data from images. In embodiments, an image may be segmented into regions, and characters or other image groups within a segmented region may be determined to be embedding sites. A data vector may be embedded into a set of corresponding ordered embedding sites by representing each data element as different intensity values assigned to the pixels within one portion of an embedding site relative to the pixels in another portion of the embedding site. In embodiments, embedded data may be extracted from an image by extracting and decoding a set of bit values from a set of identified and ordered embedding sites.
51 Citations
20 Claims
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1. A method for determining a robust average intensity of pixels from a portion of an image comprising pixels, the method comprising:
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computing a cumulative density function based upon an intensity histogram of the pixels from the portion of the image; using the cumulative density function to identify pixels to exclude; calculating a robust average intensity using at least some of the pixels that were not excluded; using the robust average intensity to determine an embed pattern in a candidate embedding site comprising pixels; and using the embed pattern to extract a data value from the candidate embedding site. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for extracting a data vector from an image comprising pixels wherein the data vector comprises data values, the method comprising:
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identifying an embed pattern in a candidate embedding site in the image wherein an embed pattern comprises a difference between a robust average intensity of pixels from a first portion of the candidate embedding site and a robust average intensity of pixels from a second portion of the candidate embedding site; correlating the embed pattern with a data value; extracting a set of data values from a set of ordered candidate embedding sites in the image; and extracting at least one data vector by segmenting the set of data values. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A system for extracting a data vector from an image comprising pixels wherein the data vector comprises data values, the system comprising:
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an embedding site ordering processor, coupled to receive a set of candidate embedding sites from the image, that orders at least some candidate embedding sites from the set of candidate embedding sites to form a set of ordered candidate embedding sites; a bitstream extractor, coupled to receive the set of ordered candidate embedding sites, that extracts a set of data values from at least some of the set of ordered candidate embedding sites wherein a data value is extracted from an ordered candidate embedding site by examining a difference between a first robust average intensity value of the pixels in a first portion of the ordered candidate embedding site and a second robust average intensity value of the pixels in a second portion of the ordered candidate embedding site; and a bitstream segmenter, coupled to receive the set of data values, that segments the set of data values to obtain at least one data vector. - View Dependent Claims (17, 18, 19, 20)
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Specification