US6037984A
Expired / Lapsed
US
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Method and apparatus for embedding a watermark into a digital image or image sequence
Assignee: Hanger Solutions LLC
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Filing: 1997-12-24
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Granted: 2000-03-14
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Expires: 2017-12-24
Abstract
Abstract A method and apparatus for watermarking an image or sequence of images without limiting the watermark signal. The watermarking apparatus includes a conventional DCT unit and quantizer for generating an array of quantized DCT coefficients. The array is watermarked by masking the array to select certain ones of the DCT coefficients that are then replaced by zero values to form a masked array. The masked array is further processed by a watermark inserter that replaces the zero valued coefficients with predefined watermark coefficients to form a watermarked array of DCT coefficients, e.g., a watermarked image. A decoder for decoding the bitstream thusly generated and for removing the embedded watermark is also taught.
Inventors
- 👤 Michael Anthony Isnardi
- 👤 Clyde Musgrave
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:02
CPC Classifications
G; G06; G06T; G06T1/00; G06T1/0021; G06T1/0028; G06T1/0035; H; H04; H04N; H04N19/00; H04N19/10; H04N19/102; H04N19/124; H04N19/126; H04N19/132; H04N19/169; H04N19/17; H04N19/176; H04N19/18; H04N19/46; H04N19/467; H04N19/50; H04N19/59; 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; G06T2201/0052; G06T2201/0053; G06T2201/0061; H04N2005/91307; H04N2005/91335
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
87 words
An image encoder for inserting a watermark into an image containing a plurality of pixels, where the pixels are encoded using discrete cosine transform (DCT) coefficients, comprising: a watermark mask for masking an array of DCT coefficients representing said image and setting select ones of said DCT coefficients in said array to a zero value; and a watermark inserter, coupled to said watermark mask, for inserting watermark values into locations in said DCT coefficient array where said DCT coefficients were masked and set to a zero value.
Claim 2
Dependent Claim
87 words
An image encoder for inserting a watermark into an image containing a plurality of pixels, where the pixels are encoded using discrete cosine transform (DCT) coefficients, comprising: a watermark mask for masking an array of DCT coefficients representing said image and setting select ones of said DCT coefficients in said array to a zero value; and a watermark inserter, coupled to said watermark mask, for inserting watermark values into locations in said DCT coefficient array where said DCT coefficients were masked and set to a zero value.
Claim 3
Dependent Claim
24 words
The apparatus of claim 1 further comprising a watermark generator for producing said watermark coefficients as quantized DCT coefficients of a predefined character string.
Claim 4
Dependent Claim
18 words
The apparatus of claim 1 further comprising a watermark generator for producing said watermark values are pseudo-randomly generated.
Claim 5
Dependent Claim
128 words
A DCT based image encoder for inserting a watermark into an image containing a plurality of pixels, where the pixels are encoded using discrete cosine transform (DCT) coefficients, comprising: a watermark mask for selecting certain ones of said DCT coefficients representing said image and changing the value of the selected DCT coefficients to zero to form a masked array of DCT coefficients; an image decoder, coupled to said watermark mask, for generating a predicted image from said masked array of DCT coefficients; a watermark inserter, coupled to said watermark mask, for replacing the selected DCT coefficients with watermark values to produce a watermarked array of DCT coefficients; an output processor, coupled to said watermark inserter, for losslessly coding said watermarked array of DCT coefficients to form a bitstream.
Claim 6
Dependent Claim
128 words
A DCT based image encoder for inserting a watermark into an image containing a plurality of pixels, where the pixels are encoded using discrete cosine transform (DCT) coefficients, comprising: a watermark mask for selecting certain ones of said DCT coefficients representing said image and changing the value of the selected DCT coefficients to zero to form a masked array of DCT coefficients; an image decoder, coupled to said watermark mask, for generating a predicted image from said masked array of DCT coefficients; a watermark inserter, coupled to said watermark mask, for replacing the selected DCT coefficients with watermark values to produce a watermarked array of DCT coefficients; an output processor, coupled to said watermark inserter, for losslessly coding said watermarked array of DCT coefficients to form a bitstream.
Claim 7
Dependent Claim
24 words
The apparatus of claim 4 further comprising a watermark generator for producing said watermark coefficients as quantized DCT coefficients of a predefined character string.
Claim 8
Dependent Claim
18 words
The apparatus of claim 4 further comprising a watermark generator for producing said watermark values are pseudo-randomly generated.
Claim 9
Dependent Claim
40 words
The apparatus of claim 6 wherein said watermark generator is coupled to said output processor and supplies said output processor with certain information useful in decoding said watermark values, where the output processor inserts the certain information into said bitstream.
Claim 10
Dependent Claim
19 words
The apparatus of claim 7 wherein said certain information is a seed for decoding said pseudo-randomly generated watermark values.
Claim 11
Independent Claim
76 words
A method of inserting a watermark into an image containing a plurality of pixels, where the pixels are encoded using discrete cosine transform (DCT) coefficients, comprising the steps of: masking an array of DCT coefficients representing said image and setting select ones of said DCT coefficients in said array to a zero value; and inserting watermark values into locations in said DCT coefficient array where said DCT coefficients were masked and set to a zero value.
Claim 12
Independent Claim
76 words
A method of inserting a watermark into an image containing a plurality of pixels, where the pixels are encoded using discrete cosine transform (DCT) coefficients, comprising the steps of: masking an array of DCT coefficients representing said image and setting select ones of said DCT coefficients in said array to a zero value; and inserting watermark values into locations in said DCT coefficient array where said DCT coefficients were masked and set to a zero value.
Claim 13
Independent Claim
85 words
A method of extracting a watermark from a bitstream comprising the steps of: extracting, from the bitstream, DCT coefficients that contain watermark values; comparing the watermark values to reference watermark values; producing an authentication signal if the watermark values match the reference watermark values; if said authentication signal is produced, setting said watermark values in said DCT coefficients of said bitstream to zero to remove the watermark from the DCT coefficients in the bitstream, whereby an image is decoded without the appearance of a watermark.
Claim 14
Independent Claim
85 words
A method of extracting a watermark from a bitstream comprising the steps of: extracting, from the bitstream, DCT coefficients that contain watermark values; comparing the watermark values to reference watermark values; producing an authentication signal if the watermark values match the reference watermark values; if said authentication signal is produced, setting said watermark values in said DCT coefficients of said bitstream to zero to remove the watermark from the DCT coefficients in the bitstream, whereby an image is decoded without the appearance of a watermark.
Claim 15
Dependent Claim
17 words
The method of claim 10 further comprising the step of recalling said reference watermark values from memory.
Claim 16
Dependent Claim
21 words
The method of claim 10 further comprising the step of: decoding information within said bitstream to produce said reference watermark values.
Claim 17
Dependent Claim
24 words
The method of claim 12 wherein said information is a seed for a pseudorandom code that forms the basis for the reference watermark values.
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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) | 2003-03-14 | 2003-09-13 | 2004-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-03-14 | 2007-09-13 | 2008-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-03-14 | 2011-09-13 | 2012-03-14 | $7700.00 | Window Closed / Lapsed |