Patent EP0953938A2 successfully refreshed from Google Patents.
EP0953938A2
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EP
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A method and apparatus for digital watermarking of images
Assignee: HP Inc
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Filing: 1999-02-10
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Granted: —
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Expires: 2019-02-10
Abstract
Abstract The present invention provides an invisible digital watermarking technique that can serve the two purposes of ownership verification and authentication, that can detect changes in pixel values as well as image size, and that may be used in public key or alternatively, secret key watermarking systems. The watermark insertion procedure computes a hash function and then combines the output of the hashed function of a modified image block, a key and various image parameters with a block of the watermark bitmap, resulting in a combined image block. As a final step to create a watermarked image block, the combined image block is inserted into the LSB of the modified image. The watermark extraction procedure takes the watermarked image block and creates two different image blocks: a first image block with the LSB's of the watermarked image block set to zero, and a second image block with the LSB's of the watermarked image block extracted. The watermark extraction procedure uses the hash function to calculate a digest of values, resulting in a hashed output. The hashed output is combined with the second image block, preferably using an exclusive OR function. The result of the combined hashed output with the second image block is a block of the extracted watermark.
Inventors
- 👤 Ping Wah Wong
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:21
CPC Classifications
G; G06; G06T; G06T1/00; G06T1/0021; G06T1/0028; G06T1/0035; H; H04; H04N; H04N1/00; H04N1/32; H04N1/32101; H04N1/32144; H04N1/32149; H04N1/32203; H04N1/32208; H04N1/32213; H04N1/32267; H04N1/32283; G06T2201/00; G06T2201/005; G06T2201/0061; H04N2201/00; H04N2201/32; H04N2201/3201; H04N2201/3225; H04N2201/3233; H04N2201/3236; H04N2201/3269; H04N2201/327
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
191 words
An electronic system for inserting a watermark into a
digital image, comprising: a means for modifying at least one predetermined bit
in an image block X r to a predetermined value, wherein
the modified image block is X r ; a means for calculating a digest of values using a
cryptographic hash function, wherein the output of the
means for calculating a digest of values is a hashed
output, wherein the means for modifying at least one
predetermined bit of the image block is electrically
coupled to the means for calculating a digest of values; a means for combining the hashed output with a
watermark, wherein the means for combining the hashed
output with a watermark is electrically coupled to the
means for calculating a digest of values, wherein the
output of the means for combining is a combined image
block; and a means for inserting a first image block into the
modified image block X r , wherein the means for inserting
the first image block into the modified image block X r is
electrically coupled to the means for modifying at least
one predetermined bit of the image block.
Claim 2
Dependent Claim
20 words
The electronic system recited in claim 1 wherein the
first image block is the combined image block C r .
Claim 3
Dependent Claim
20 words
The electronic system recited in claim 1 wherein the
first image block is an encrypted image block W r .
Claim 4
Dependent Claim
38 words
The electronic system recited in claim 2 wherein the
means for combining the hashed output with a watermark is
electrically coupled to the means for inserting the first
image block into the modified image block X r .
Claim 5
Dependent Claim
27 words
The electronic system recited in claim 1 wherein the
means for modifying at least one predetermined bit
modifies the LSB of the image block X r .
Claim 6
Dependent Claim
23 words
The electronic system recited in claim 1 wherein the
means for combining the hashed output with a watermark is
an XOR logic block.
Claim 7
Dependent Claim
37 words
The electronic system recited in claim 1 wherein the
means for modifying at least a predetermined bit to a
predetermined value modifies the at least one
predetermined bit independently for each color plane of
the image block.
Claim 8
Dependent Claim
48 words
The electronic system recited in claim 3 further
including an encryption means, wherein the encryption
means is electrically coupled to both the means for
combining the hashed output with a watermark and the
means for inserting a first image block into the modified
image block X r .
Claim 9
Dependent Claim
122 words
An electronic system for extracting a watermark from
a digital image comprising: a means for modifying at least a predetermined bit of
the watermarked image to a predetermined value; means for extracting at least a predetermined bit
from the watermarked image block; means for calculating a digest of values using a
cryptographic hash function, wherein the output of the
means for calculating a digest of values using a
cryptographic hash function is a hashed output, wherein
the means for modifying at least a predetermined bit of
the watermarked image is electrically coupled to the
means for calculating a digest of values; and means for combining, wherein the means for combining
is electrically coupled to the means for calculating a
digest of values.
Claim 10
Dependent Claim
30 words
The electronic system recited in claim 9 wherein the
means for combining is electrically coupled to the means
for extracting at least a predetermined bit from the
watermarked image block.
Claim 11
Dependent Claim
39 words
The electronic system recited in claim 9 further
including a decryption means, wherein the decryption
means is electrically coupled to the means for extracting
at least a predetermined bit from the watermarked image
block and the means for combining.
Claim 12
Dependent Claim
30 words
The electronic system recited in claim 9 wherein the
means for modifying at least a predetermined bit to a
predetermined value modifies the least significant bit of
the image block.
Claim 13
Independent Claim
123 words
A method for inserting a watermark into a digital
image including the steps of: partitioning the image block X r into at least one I x
J block: for each I x J block, modifying at least a
predetermined bit of each I x J block to a predetermined
value, wherein the modified image block is X r ; calculating a digest of the values using a
cryptographic hash function; combining the hashed output calculated in the
previous step with a watermark bitmap B r , wherein the
output of the step of combining the hashed output with a
watermark B r is a combined image block C r ; and inserting a first image block into the modified image
X r .
Claim 14
Dependent Claim
19 words
The method recited in claim 13 wherein the first
image block is the combined image block C r .
Claim 15
Dependent Claim
19 words
The method recited in claim 13 wherein the first
image block is an encrypted image block W r .
Claim 16
Dependent Claim
33 words
The method recited in claim 13 further including the
step of encrypting the combined image block, wherein the
result of encrypting the combined image block is the
encrypted image block W r .
Claim 17
Dependent Claim
26 words
The method recited in claim 13 wherein the at least
one predetermined bit of the image block X r is modified
by discarding the predetermined bit.
Claim 18
Dependent Claim
38 words
The method recited in claim 13 wherein the step of
modifying at least one predetermined bit of the image
block X r a plurality of bits are modified by setting the
predetermined pattern of bits to predetermined values.
References Cited (Backward Citations)
No citation records indexed.
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