Identifying Steganographic Data in an Image
First Claim
1. A method for identifying a robust average intensity of a portion of an embedding site comprising a plurality of pixels of a common class to extract a data value represented as a difference between a first robust average intensity value of a first portion of the plurality of pixels in the embedding site and a second robust average intensity value of a second portion of the plurality of pixels in the embedding site, the method comprising:
- selecting reliable intensity value pixels from a first portion of the plurality of pixels to form a first set of reliable pixels;
iteratively pruning, from the first set of reliable pixels, reliable intensity value pixels that reside in an outer region of a histogram of the first set of reliable pixels until a difference between successive average intensity values of the first set of reliable pixels is less than a difference threshold; and
setting a first robust average intensity value of the first set of reliable pixels based upon at least one of the successive average intensity values that had less than a difference threshold.
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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.
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Citations
20 Claims
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1. A method for identifying a robust average intensity of a portion of an embedding site comprising a plurality of pixels of a common class to extract a data value represented as a difference between a first robust average intensity value of a first portion of the plurality of pixels in the embedding site and a second robust average intensity value of a second portion of the plurality of pixels in the embedding site, the method comprising:
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selecting reliable intensity value pixels from a first portion of the plurality of pixels to form a first set of reliable pixels; iteratively pruning, from the first set of reliable pixels, reliable intensity value pixels that reside in an outer region of a histogram of the first set of reliable pixels until a difference between successive average intensity values of the first set of reliable pixels is less than a difference threshold; and setting a first robust average intensity value of the first set of reliable pixels based upon at least one of the successive average intensity values that had less than a difference threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for calculating a robust average intensity of a portion of an embedding site comprising a plurality of pixels wherein an embedded data value represents a difference between a first robust average intensity value of a first portion of the plurality of pixels in the embedding site and a second robust average intensity value of a second portion of the plurality of pixels in the embedding site, the method comprising:
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[a] responsive to a pixel from the plurality of pixels belonging to a neighborhood of pixels from the plurality of pixels, adding the pixel to a set of reliable pixels; [b] identifying a portion set of reliable pixels comprised of reliable pixels from the set of reliable pixels that reside within a portion of the embedding site; [c] calculating a first average intensity value of the portion set of reliable pixels; [d] calculating a standard deviation of the portion set of reliable pixels; [e] generating a pruned portion set of the reliable pixels by removing reliable pixels from the portion set of reliable pixel that do not have an intensity within a range defined by the average intensity value minus a first value multiplied by the standard deviation and the average intensity value plus a second value multiplied by the standard deviation; [f] calculating a second average intensity value of the pruned portion set of the reliable pixels; [g] responsive to a difference between the first average intensity value and the second average intensity value being greater than a difference threshold value; setting the pruned portion set of the reliable pixels as the portion set of reliable pixels; setting the second average intensity as the first average intensity; and repeating steps [d] and [g]; [h] responsive to a difference between the first average intensity value and the second average intensity value being less than a difference threshold value, selecting the second average intensity value as a first robust average intensity value of the portion set of reliable pixels. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A system for extracting a set of data values from a set of ordered embedding sites, an embedding site comprising pixels, the system comprising:
a bitstream extractor, coupled to receive the set of ordered embedding sites, that extracts a set of data values wherein a data value is extracted from an embedding site from the set of ordered embedding sites by; selecting reliable intensity value pixels from a first portion of pixels from the embedding site to form a first set of reliable pixels and selecting reliable intensity value pixels from a second portion of the pixels from the embedding site to form a second set of reliable pixels; iteratively pruning, from the first set of reliable pixels, reliable intensity value pixels that reside in an outer region of a histogram of the first set of reliable pixels until a difference between successive average intensity values of the first set of reliable pixels is less than a difference threshold and setting a first robust average intensity value of the first set of reliable pixels based upon at least one of the successive average intensity values that had less than a difference threshold; iteratively pruning, from the second set of reliable pixels, reliable intensity value pixels that reside in an outer region of a histogram of the second set of reliable pixels until a difference between successive average intensity values of the second set of reliable pixels is less than a difference threshold and setting a second robust average intensity value of the second set of reliable pixels based upon at least one of the successive average intensity values that had less than a difference threshold; responsive to a difference between the first robust average intensity value and the second robust average intensity value being greater than a threshold, extracting an embed pattern by determining which of the first and second robust average intensity values is greater than the other robust average intensity value; and correlating the embed pattern with the data value. - View Dependent Claims (15, 16, 17, 18, 19, 20)
Specification