US6798894B2
Expired / Lapsed
US
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Method and apparatus for watermarking video images
Assignee: Digimarc Corp
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Filing: 2001-02-06
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Granted: 2004-09-28
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Expires: 2021-02-06
Abstract
Abstract Embedding a watermark in an image by changing selected DCT coefficients in the blocks and macro blocks of coefficients which represent the image. The changes in the blocks that comprise each macro block are done in a coordinated manner so that the phase of the watermark signal is preserved across the block boundaries. By preserving the phase across block boundaries, a detectable grid is formed which can be used as an orientation and scaling grid. Furthermore, by preserving the phase across block boundaries the visual artifacts introduced by the watermark are minimized. The bit rate of the image signal is preserved by maintaining a count (referred to as the cumulative change count) that represents the amount that the bit rate has been increased by changes in coefficients less the amount that the bit rate has been decreased by changes in the coefficients. If at any time the cumulative change count exceeds a pre-established limit, coefficient changes that decrease the cumulative change count continue; however, coefficient changes that increase the cumulative change count are suspended. The suspension of coefficient changes that increase the cumulative change count continues until the cumulative change count falls below the pre-established limit.
Inventors
- 👤 Geoffrey B. Rhoads
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:18
CPC Classifications
G; G06; G06T; G06T1/00; G06T1/0021; G06T1/0028; G06T1/0035; G06T1/005; G06T1/0064; G06V; G06V30/00; G06V30/40; G10; G10L; G10L19/00; G10L19/018; H; H04; H04N; H04N1/00; H04N1/00002; H04N1/00005; H04N1/00026; H04N1/00037; H04N1/00071; H04N1/00074; H04N1/00079; H04N1/32; H04N1/32101; H04N1/32144; H04N1/32149; H04N1/32154; H04N1/32165; H04N1/32187; H04N1/32267; H04N1/32277; H04N1/32352; H04N19/00; H04N19/46; H04N19/467; H04N19/48; H04N19/60; H04N19/61; H04N21/00; H04N21/20; H04N21/23; H04N21/238; H04N21/2389; H04N21/23892; H04N21/80; H04N21/83; H04N21/835; H04N21/8358; H04N5/00; H04N5/76; H04N5/91; H04N5/913; G06T2201/00; G06T2201/005; G06T2201/0051; G06T2201/0052; G06T2201/0053; G06T2201/0061; G11; G11B; G11B20/00; G11B20/00086; G11B20/00884; G11B20/10; G11B20/10527; G11B2020/10537; H04N1/32106; H04N1/32122; H04N2005/91307; H04N2005/91335; H04N2201/00; H04N2201/32; H04N2201/3201; H04N2201/3204; H04N2201/3205; H04N2201/3207; H04N2201/3225; H04N2201/3233; H04N2201/3269; H04N2201/327
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
153 words
A method of introducing a watermark into a stream of bits comprising variable length codes that represent transform domain samples while insuring that a bit rate of said stream of bits is maintained within a pre-established limit, said method comprising, providing a watermark signal comprising changes to associated transform domine samples to embed the watermark signal in the samples, maintaining a cumulative change amount which indicates an amount of the positive and negative changes which are made to said codes as a result of embedding the watermark signal, adjusting the watermark signal changes to particular transform samples such that the amount of the adjustment and the change to the particular transform samples is non-zero yet the cumulative change amount is maintained below the pre-established limit, and suspending positive changes if the cumulative change amount exceeds the pre-established limit, whereby the bit rate of said stream of bits is maintained within the pre-established limit.
Claim 2
Independent Claim
153 words
A method of introducing a watermark into a stream of bits comprising variable length codes that represent transform domain samples while insuring that a bit rate of said stream of bits is maintained within a pre-established limit, said method comprising, providing a watermark signal comprising changes to associated transform domine samples to embed the watermark signal in the samples, maintaining a cumulative change amount which indicates an amount of the positive and negative changes which are made to said codes as a result of embedding the watermark signal, adjusting the watermark signal changes to particular transform samples such that the amount of the adjustment and the change to the particular transform samples is non-zero yet the cumulative change amount is maintained below the pre-established limit, and suspending positive changes if the cumulative change amount exceeds the pre-established limit, whereby the bit rate of said stream of bits is maintained within the pre-established limit.
Claim 3
Independent Claim
154 words
A method of introducing a watermark into a stream of bits comprising variable length codes that represent transform domain samples while insuring that a bit rate of said stream of bits is maintained within a pre-established limit, said system comprising, means for providing a watermark signal comprising changes to associated transform domine samples to embed the watermark signal in the samples, means for maintaining a count of and amount of positive and negative changes which are made to said codes as a result of embedding the watermark signal, mean for adjusting the watermark signal changes to particular transform samples such that the amount of the adjustment and the change to the particular transform samples is non-zero yet the cumulative change amount is maintained below the pre-established limit, and means for suspending positive changes if a pre-established limit is exceeds, whereby the bit rate of said stream of bits is maintained within the pre-established limit.
Claim 4
Independent Claim
154 words
A method of introducing a watermark into a stream of bits comprising variable length codes that represent transform domain samples while insuring that a bit rate of said stream of bits is maintained within a pre-established limit, said system comprising, means for providing a watermark signal comprising changes to associated transform domine samples to embed the watermark signal in the samples, means for maintaining a count of and amount of positive and negative changes which are made to said codes as a result of embedding the watermark signal, mean for adjusting the watermark signal changes to particular transform samples such that the amount of the adjustment and the change to the particular transform samples is non-zero yet the cumulative change amount is maintained below the pre-established limit, and means for suspending positive changes if a pre-established limit is exceeds, whereby the bit rate of said stream of bits is maintained within the pre-established limit.
Claim 5
Dependent Claim
20 words
The method of claim 1 wherein negative changes are suspended if the cumulative change amount exceeds a pre-established negative amount.
Claim 6
Dependent Claim
20 words
The system of claim 2 including means for suspending any negative changes if said count exceeds a pre-established negative limit.
Claim 7
Independent Claim
103 words
A method of embedding a watermark in a stream of coded symbols that represent a series of images by selectively increasing or decreasing values of said symbols according to associated values of the watermark, said method comprising, establishing a limit on allowable entropy of said stream of bits, adjusting an amount of the selective increasing or decreasing of the values of said symbols as entropy of the watermarked stream approaches the limit such that the watermark and the adjustment to the watermark is non-zero at selected symbols where the watermark is adjusted to maintain the entropy of the watermarked stream below the limit.
Claim 8
Independent Claim
103 words
A method of embedding a watermark in a stream of coded symbols that represent a series of images by selectively increasing or decreasing values of said symbols according to associated values of the watermark, said method comprising, establishing a limit on allowable entropy of said stream of bits, adjusting an amount of the selective increasing or decreasing of the values of said symbols as entropy of the watermarked stream approaches the limit such that the watermark and the adjustment to the watermark is non-zero at selected symbols where the watermark is adjusted to maintain the entropy of the watermarked stream below the limit.
Claim 9
Independent Claim
95 words
A method of embedding a watermark in a series of bit which represent an image without increasing entropy of said image beyond a pre established limit, comprising the steps of: changing selective bits of said image to embed said watermark, maintaining a cumulative change count of the changes made to embed said watermark in said image, adjusting intensity of the watermark for at least a set of the selective bits to maintain the cumulative change count below the limit, where the adjustment and the intensity of the watermark is non-zero at the set of bits.
Claim 10
Independent Claim
95 words
A method of embedding a watermark in a series of bit which represent an image without increasing entropy of said image beyond a pre established limit, comprising the steps of: changing selective bits of said image to embed said watermark, maintaining a cumulative change count of the changes made to embed said watermark in said image, adjusting intensity of the watermark for at least a set of the selective bits to maintain the cumulative change count below the limit, where the adjustment and the intensity of the watermark is non-zero at the set of bits.
Claim 11
Independent Claim
95 words
A method of embedding a watermark in a series of bit which represent an image without increasing entropy of said image beyond a pre established limit comprising the steps of: maintaining a count which represents a change in entropy as said watermark is being embedded in said image, adjusting intensity of the watermark for at least a set bits to maintain the count below the limit, where the adjustment and the intensity of the watermark is non-zero at the set of bits, suspending changes in said image when said count is beyond a specified limit.
Claim 12
Independent Claim
95 words
A method of embedding a watermark in a series of bit which represent an image without increasing entropy of said image beyond a pre established limit comprising the steps of: maintaining a count which represents a change in entropy as said watermark is being embedded in said image, adjusting intensity of the watermark for at least a set bits to maintain the count below the limit, where the adjustment and the intensity of the watermark is non-zero at the set of bits, suspending changes in said image when said count is beyond a specified limit.
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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) | 2007-09-28 | 2008-03-29 | 2008-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-09-28 | 2012-03-29 | 2012-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-09-28 | 2016-03-29 | 2016-09-28 | $7700.00 | Window Closed / Lapsed |