US5721788A
Expired / Lapsed
US
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Method and system for digital image signatures
Assignee: Digimarc Corp
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Filing: 1992-07-31
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Granted: 1998-02-24
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Expires: 2012-07-31
Abstract
Abstract A method and system for embedding signatures within visual images in both digital representation and print or film. A signature is inseparably embedded within the visible image, the signature persisting through image transforms that include resizing as well as conversion to print or film and back to digital form. Signature points are selected from among the pixels of an original image. The pixel values of the signature points and surrounding pixels are adjusted by an amount detectable by a digital scanner. The adjusted signature points form a digital signature which is stored for future identification of subject images derived from the image. In one embodiment, a signature is embedded within an image by locating relative extrema in the continuous space of pixel values and selecting the signature points from among the extrema. Preferably, the signature is redundantly embedded in the image such that any of the redundant representations can be used to identify the signature. Identification of a subject image includes ensuring that the subject image is normalized with respect to the original image or the signed image. Preferably, the normalized subject image is compared with the stored digital signature.
Inventors
- 👤 Robert D. Powell
- 👤 Mark J. Nitzberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:42
CPC Classifications
G; G06; G06T; G06T1/00; G06T1/0021; G06T1/005; G06T1/0064; G06Q; G06Q20/00; G06Q20/30; G06Q20/34; G06Q20/341; G06T1/0028; G07; G07D; G07D7/00; G07D7/004; G07D7/0047; G07D7/005; G07D7/0054; G07D7/0056; G07D7/06; G07D7/12; G07D7/20; G07D7/2008; G07D7/202; G07D7/2033; G07F; G07F7/00; G07F7/08; G07F7/12; H; H04; H04N; H04N1/00; H04N1/32; H04N1/32101; H04N1/32144; H04N1/32149; H04N1/32203; H04N1/32208; H04N1/32229; H04N1/32245; H04N1/32251; H04N1/32288; H04N1/3232; G06T2201/00; G06T2201/005; G06T2201/0051; G06T2201/0081; H04N2201/00; H04N2201/32; H04N2201/3201; H04N2201/3225; H04N2201/3233; H04N2201/3235; H04N2201/3269; H04N2201/327
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
128 words
A method of image signature processing of an original image having pixels with pixel values, the pixel values including a plurality of pixel values intermediate to minimum and maximum pixel values, comprising: locating a plurality of candidate points from among the pixels of the original image; selecting a first plurality of signature points from among the candidate points; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; and digitally storing the signature in a database for future identification.
Claim 2
Independent Claim
128 words
A method of image signature processing of an original image having pixels with pixel values, the pixel values including a plurality of pixel values intermediate to minimum and maximum pixel values, comprising: locating a plurality of candidate points from among the pixels of the original image; selecting a first plurality of signature points from among the candidate points; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; and digitally storing the signature in a database for future identification.
Claim 3
Dependent Claim
34 words
The method according to claim 1 wherein the candidate points are located by locating relative extrema in the original image and wherein the selecting step includes selecting the signature points from among the extrema.
Claim 4
Dependent Claim
34 words
The method according to claim 2 wherein the pixel values of the original image include luminance values and the extrema are relative minima or maxima luminance values of the pixels of the original image.
Claim 5
Dependent Claim
31 words
The method according to claim 1, further comprising adjusting a plurality of pixel values surrounding the signature points to provide smooth transitions to the adjusted pixel values at the signature points.
Claim 6
Dependent Claim
41 words
The method according to claim 1, further comprising: selecting a second plurality of signature points from among the candidate points; and adjusting the pixel values of the second plurality of signature points to form a redundant signature for the signed image.
Claim 7
Independent Claim
101 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; and digitally storing the signature in a database for future identification.
Claim 8
Independent Claim
101 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; and digitally storing the signature in a database for future identification.
Claim 9
Dependent Claim
14 words
The method according to claim 6 wherein the pixel values adjusted are luminance values.
Claim 10
Dependent Claim
14 words
The method according to claim 6 wherein the pixel values adjusted are color values.
Claim 11
Dependent Claim
36 words
The method according to claim 6, further comprising analyzing whether a digital subject image constitutes or is derived from a signed image having pixel values that were adjusted to form a signature according to claim 6.
Claim 12
Dependent Claim
33 words
The method according to claim 9 wherein the analyzing step includes subtracting the subject image from the original image to obtain a resulting image and comparing the resulting image with the stored signature.
Claim 13
Dependent Claim
19 words
The method according to claim 9 wherein the analyzing step includes comparing the subject image with the signed image.
Claim 14
Dependent Claim
51 words
The method according to claim 9 wherein the analyzing step includes selecting a potential signature point in the subject image corresponding to a signature point of the signed image and comparing the pixel value of the selected point to the pixel value of the corresponding signature point of the signed image.
Claim 15
Dependent Claim
67 words
The method according to claim 9 wherein the analyzing step includes selecting a potential signature point in the subject image corresponding to a signature point of the signed image, computing an average of pixel values of the potential signature point and a plurality of pixels surrounding the potential signature point, and comparing the average to the pixel value of the corresponding signature point of the signed image.
Claim 16
Independent Claim
117 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; storing the signature for future identification; and locating relative extrema in the original image, wherein the selecting step includes selecting the signature points from among the extrema.
Claim 17
Independent Claim
117 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; storing the signature for future identification; and locating relative extrema in the original image, wherein the selecting step includes selecting the signature points from among the extrema.
Claim 18
Dependent Claim
34 words
The method according to claim 14 wherein the pixel values of the original image include luminance values and the extrema are relative minima or maxima luminance values of the pixels of the original image.
Claim 19
Independent Claim
132 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; storing the signature for future identification; selecting a second plurality of signature points from among the pixels of the original image; and adjusting the pixel values of the second plurality of signature points to form a redundant signature for the signed image.
Claim 20
Independent Claim
132 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; storing the signature for future identification; selecting a second plurality of signature points from among the pixels of the original image; and adjusting the pixel values of the second plurality of signature points to form a redundant signature for the signed image.
Claim 21
Independent Claim
127 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; and storing the signature for future identification, wherein the digital image has a border surrounding the image and the pixels whose values adjusted are selected so as not to be within a predetermined distance from the border.
Claim 22
Independent Claim
127 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; and storing the signature for future identification, wherein the digital image has a border surrounding the image and the pixels whose values adjusted are selected so as not to be within a predetermined distance from the border.
Claim 23
Independent Claim
120 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; storing the signature for future identification; and adjusting a plurality of pixel values surrounding the signature points to provide smooth transitions to the adjusted pixel values at the signature points.
Claim 24
Independent Claim
120 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; storing the signature for future identification; and adjusting a plurality of pixel values surrounding the signature points to provide smooth transitions to the adjusted pixel values at the signature points.
Claim 25
Dependent Claim
134 words
A method of image signature processing of an original image having pixels with pixel values, comprising: selecting a first plurality of signature points from among the pixels of the original image; forming a signature by adjusting the pixel values of the signature points within the original image, thereby resulting in a signed image that includes the signature and pixel values of the original image that have not been adjusted to form the signature, the signed image including a plurality of pixel values intermediate to the minimum and maximum pixel values; storing the signature for future identification; and analyzing whether a digital subject image constitutes or is derived from a signed image having pixel values that were adjusted to form a signature according to claim 6, wherein the analyzing step includes normalizing the subject image.
Claim 26
Dependent Claim
23 words
The method according to claim 19 wherein the normalizing step includes aligning the subject image with the signed image or the original image.
Claim 27
Dependent Claim
37 words
The method according to claim 20 wherein the aligning step includes selecting three or more pixels in the subject image and aligning the three or more pixels with corresponding pixels in the original or the signed image.
Claim 28
Dependent Claim
55 words
The method according to claim 19 wherein the pixel values of the subject image and the original image include luminance values and the normalizing step includes adjusting the luminance values of a subset of the pixels in the subject image to equal the luminance values of a corresponding subset of pixels in the original image.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-02-23 | 2001-08-25 | 2002-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-02-23 | 2005-08-25 | 2006-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-02-23 | 2009-08-25 | 2010-02-24 | $7700.00 | Window Closed / Lapsed |