EP0967803A2
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EP
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Robust digital watermarking
Assignee: NEC Corp
•
Filing: 1999-06-23
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Granted: —
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Expires: 2019-06-23
Abstract
Abstract A watermarking procedure that is applicable to images, audio, video and multimedia data to be watermarked divides the data to be watermarked into a set of n×n blocks, such as the 8×8 blocks of MPEG. The same watermark signal can be distributed throughout the set of blocks in a large variety of ways. This allows the insertion algorithm to be changed without affecting the decoders. The decoding procedure first sums together the DCT coefficients of N sets of 8×8 blocks to form a set of N summed 8×8 blocks and then extracts the watermark from the summed block. Since the sum of the DCT blocks is equal to the DCT of the sum of the intensity blocks, efficient decoding can occur in both the spatial and frequency domains. The symmetric nature of the decoding process allows geometric distortions to be handled in the spatial domain and other signal distortions to be handled in the frequency domain. Moreover, insertion of a watermark signal into image data and the subsequent extraction of the watermark from watermarked image data which has been subject to distortion between the times of insertion and extraction involves the insertion of multiple watermarks designed to survive predefined distortions of the image data, such as panscan or letterbox mode transformations. Alternatively, a registration pattern in the image data, after the image data containing the registration pattern is subject to an unknown distortion, is used to compensate for distortion of the watermarked image data.
Inventors
- 👤 Ingemar J. Cox
- 👤 Matthew L. Miller
- 👤 Ryoma Oami
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 14:44
CPC Classifications
G; G06; G06T; G06T1/00; G06T1/0021; G06T1/0028; G06T1/005; G06T1/0064; H; H04; H04N; H04N1/00; H04N1/32; H04N1/32101; H04N1/32144; H04N1/32149; H04N1/32154; H04N1/32165; H04N1/32187; H04N1/32192; H04N1/32267; H04N1/32277; H04N1/32288; H04N1/32304; H04N19/00; H04N19/46; H04N19/467; H04N21/00; H04N21/80; H04N21/83; H04N21/835; H04N21/8358; H04N7/00; H04N7/24; G06T2201/00; G06T2201/005; G06T2201/0052; H04N2201/00; H04N2201/32; H04N2201/3201; H04N2201/3225; H04N2201/3233; H04N2201/3269; H04N2201/327
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
49 words
A method of inserting a watermark signal into
data to be watermarked comprising the steps of: applying a watermark extraction to unwatermarked
data for generating extracted values; computing the difference between a watermark to be
inserted and the extracted values; and adding the computed difference throughout the
unwatermarked data.
Claim 2
Dependent Claim
38 words
A method of inserting a watermarked signal into
data to be watermarked as set forth in claim 1, wherein
said adding the computed difference comprises
distributing the computed difference according to a
perceptual model of human visual sensitivity.
Claim 3
Dependent Claim
51 words
A method of inserting a watermarked signal into
data to be watermarked as set forth in claim 1, wherein
said adding the computed difference comprises
distributing the computed difference according to how
affected the data will be to a predetermined attack so
that the attack will not affect the watermarked data.
Claim 4
Dependent Claim
40 words
A method of inserting a watermarked signal into
data to be watermarked as set forth in claim 1, wherein
said adding the computed difference comprises
distributing the computed difference according to a
stochastic method to reduce the susceptibility to
tampering.
Claim 5
Dependent Claim
69 words
A method of inserting a watermarked signal into
data to be watermarked as set forth in claim 1, wherein
said unwatermarked data is compressed video and said
compressed video is divided into groups of blocks, where
said computing the difference computes the difference
between a watermark and the sum of the extracted values
from each group of blocks and said adding distributes the
difference into the group of blocks.
Claim 6
Dependent Claim
34 words
A method of inserting a watermarked signal into
data to be watermarked as set forth in claim 5, wherein
said groups of blocks are selected according to response
to predetermined attacks and signal degradations.
Claim 7
Independent Claim
67 words
A method of detecting a watermark from
watermarked data comprising the steps of: receiving watermarked data where the watermarked
data comprises n×n blocks of watermarked data; summing the n×n blocks of watermarked data to form
at least one n×n block of summed watermarked data; cyclically shifting the block in the spatial domain
to register the block; and extracting the watermark from the at least one n×n
block.
Claim 8
Independent Claim
72 words
A method of detecting a watermark from
watermarked data comprising the steps of: receiving watermarked data where the watermarked
data comprises n×n blocks of watermarked data; summing the n×n blocks of watermarked data to form
at least one n×n block of summed watermarked data; and extracting the watermark from the at least one n×n
block by summing predetermined watermarked data from each
n×n block to yield each element of the extracted
watermark.
Claim 9
Dependent Claim
30 words
A method of detecting a watermark from
watermarked data as set forth in claim 8, wherein said
extracting is performed in the spatial domain using at
least one n×n blocks.
Claim 10
Dependent Claim
30 words
A method of detecting a watermark from
watermarked data as set forth in claim 8, wherein said
extracting is performed in the frequency domain using at
least one n×n blocks.
Claim 11
Independent Claim
28 words
A method of detecting a watermark from
watermarked data as set forth in
any of claims 8 to 10,
wherein each
n×n block is filtered before said extracting.
Claim 12
Independent Claim
70 words
A method of detecting a watermark from
watermarked data comprising the steps of: receiving watermarked data where the watermarked
data comprises n×n blocks of watermarked data; summing the n×n blocks of watermarked data to form M
n×n blocks of summed watermarked data, where M is the
number of functions mapping frequency indices onto the
indices of elements of watermarks; and extracting the watermark from the at least one n×n
block.
Claim 13
Dependent Claim
24 words
A method of detecting a watermark from
watermarked data as set forth in claim 12, wherein said
forming is performed in the spatial domain.
Claim 14
Dependent Claim
24 words
A method of detecting a watermark from
watermarked data as set forth in claim 12, wherein said
forming is performed in the frequency domain.
Claim 15
Independent Claim
259 words
A method of inserting a watermark signal into
video images comprising the steps of: receiving input video images; performing discrete cosine transformation (DCT) of
said input video images to obtain input video image DCT
values; adding watermark signals to said input video image
DCT values to obtain watermarked DCT values; performing an inverse DCT on the watermarked DCT
values for generating watermarked images; subtracting predicted images stored in memory from
said watermarked images for generating residual images; performing discrete cosine transformation of said
residual images to obtain residual image DCT values and
quantizing the residual image DCT values to derive
residual image quantized DCT values; inverse quantizing the residual image quantized DCT
values to obtain residual image de-quantized DCT values; performing discrete cosine transformation of the
predicted images to obtain predicted image DCT values; summing the residual image de-quantized DCT values
and the predicted image DCT values for generating decoded
image DCT coefficients; calculating correction signals by applying a
watermark extraction to the decoded image DCT
coefficients and comparing resultant extracted values
with watermark target values; adding the correction signals to the residual image
quantized DCT values for obtaining an output signal; inverse quantizing the output signal to obtain
inverse quantized output data, perforing inverse DCT of
the inverse quantized output signal and summing the
resultant signal with the predicted images for generating
a summed signal; generating predicted images to be stored in said
memory by using the summed signal; and variable length encoding the output signal for
providing a watermarked MPEG video signal of the input
video images.
Claim 16
Independent Claim
235 words
A method of inserting a watermark signal into
video images comprising the steps of: receiving input video images; performing discrete cosine transformation (DCT) of
said input video images to obtain input video image DCT
values; adding watermark signals to said input video image
DCT values to obtain watermarked DCT values; performing discrete cosine transformation on
predicted images stored in memory to obtain predicted
image DCT values; subtracting the predicted image DCT values from the
watermarked DCT values to obtain residual image DCT
values; quantizing the residual image DCT values to obtain
residual image quantized DCT values; inverse quantizing the residual image quantized DCT
values to obtain residual image de-quantized DCT values
and summing the residual image de-quantized DCT values
with the predicted image DCT values, for generating
decoded image DCT coefficients; calculating correction signals by applying a
watermark extraction to the decoded image DCT
coefficients and comparing resultant extracted values
with watermark target values; summing the correction signals with the residual
image quantized DCT values to obtain an output signal; inverse quantizing the output signal to obtain
inverse quantized output signal, performing inverse DCT
of the inverse quantized output signal and summing the
resultant signal with the predicted images to provide
locally-decoded images; generating predicted images to be stored in said
memory using the locally-decoded images; and valuable length encoding the output signal to
provide a watermarked MPEG video signal of the input
video images.
Claim 17
Dependent Claim
67 words
A method of inserting a watermark signal into
video images as set forth in claim 15 or 16, wherein said
calculating step generates a negative value as said
correction signal when the extracted value exceeds the
corresponding value of said watermark target values, and
generates a positive value as said correction signal when
the extracted value falls short of the corresponding
value of said watermark target values.
Claim 18
Dependent Claim
41 words
A method of inserting a watermark signal into
video images as set forth in claim 17, wherein said
calculating step generates a zero value as the correction
signal if the corresponding value of said residual image
quantized DCT values is zero.
Claim 19
Dependent Claim
30 words
A method of inserting a watermark signal into
video images as set forth in claim
17 or 18,
wherein said
positive value is +1 and said negative value is -1.
Claim 20
Independent Claim
118 words
A method of inserting an extractable watermark
signal into image data so that the watermark signal can
be extracted after the watermarked data is subject to
distortion comprising the steps of: providing image data to be watermarked; copying the image data; applying a predefined distortion to the copy of
image data; inserting a watermark signal into the distorted
copy of image data; subtracting the copy of distorted image data from
the watermarked copy of distorted image data to generate
a watermark pattern; performing inverse distortion on the watermark
pattern to generate the watermarked pattern for
nondistorted image data; and combining said image data to be watermarked and
said watermark pattern for nondistorted image data to
obtain watermarked data.
Claim 21
Dependent Claim
25 words
A method of inserting a watermark signal into
image data as set forth in claim 20, wherein said
predetermined distortion is panscan mode image data.
Claim 22
Dependent Claim
25 words
A method of inserting a watermark signal into
image data as set forth in claim 20, wherein said
predetermined distortion is letterbox mode image data.
Claim 23
Dependent Claim
24 words
A method of inserting a watermark signal into
image data as set forth in claim 20, wherein said
combining includes combining with perceptual modeling.
Claim 24
Independent Claim
49 words
A method of inserting an extractable watermark
signal into image data so that the watermark signal can
be extracted after the watermarked data is subject to
distortion comprising the steps of: receiving image data in form of n×n blocks; and inserting an n×n registration pattern into the image
data.
Claim 25
Dependent Claim
45 words
A method of inserting an extractable watermark
signal into image data as set forth in claim 24, wherein
said inserting is performed by converting the
registration pattern into the DCT domain and then
inserting the DCT values of the registration pattern into
the image data.
Claim 26
Independent Claim
130 words
A method of detecting a watermark from
watermarked image data that has been subjected to a two
dimensional translation distortion comprising the steps
of: partitioning received distorted watermarked image
data into a set of n×n blocks; summing together watermarked image data in a
predetermined number of n×n blocks; if summed n×n blocks are not in spatial domain,
transforming summed n×n blocks into spatial domain; determining two-dimensional translation distortion
of the summed n×n blocks; shifting the summed n×n blocks according to the
determined distortion; transforming the shifted n×n blocks into transform
domain; extracting a possible watermark signal from the
transformed n×n blocks; correlating the possible watermark with a known
watermark; repeating said correlating for cyclic shifts of the
possible watermark; and determining the presence of a watermark based on
said correlating.
Claim 27
Dependent Claim
35 words
A method of detecting a watermark from
watermarked image data as set forth in claim 26, where
the two dimensional translation is a geometric shift in
at least one of the horizontal or vertical direction.
Claim 28
Independent Claim
144 words
A method of detecting a watermark from
watermarked image data that has been subjected to a two
dimensional translation distortion comprising the steps
of: (a) partitioning received distorted watermarked
image data in n×n blocks; (b) summing together watermarked image data in a
predetermined number of n×n blocks; (c) if summed n×n blocks are not in spatial domain,
transforming summed n×n blocks into spatial domain; (d) shifting the summed n×n blocks by one of n 2 possible shifts; (e) transforming the shifted n×n blocks into
transform domain; (f) extracting a possible watermark signal from the
transformed n×n blocks; (g) correlating the possible watermark with a known
watermark; (h) repeating said correlating for cyclic shifts of
the possible watermark; (i) repeating steps (d)-(h) for each of the n 2 possible shifts; and (j) determining the presence of a watermark based
on the results of step (i).
Claim 29
Dependent Claim
26 words
A method of detecting a watermark from
watermarked image data as set forth in claim 26 or 28, wherein
said n×n block is a 8×8 block.
Claim 30
Dependent Claim
28 words
A method of detecting a watermark from
watermarked image data as set forth in claim 26 or 28, wherein
said correlating is performed for n 2 possible shifts.
References Cited (Backward Citations)
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