Image analysis – Image compression or coding
Reexamination Certificate
1998-11-05
2002-11-05
Johns, Andrew W. (Department: 2621)
Image analysis
Image compression or coding
C382S251000
Reexamination Certificate
active
06477276
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an apparatus for, and a method of, embedding and extracting digital information, as well as a medium having a program for carrying out the method recorded thereon. More particularly, the present invention generally relates to an apparatus for, and a method of, embedding, in order to protect the copyright of digital data, digital data such as copyright information (hereinafter referred to as digital information) in an image signal, and extracting the embedded digital information, as well as a medium having a program for carrying out the method recorded thereon.
2. Description of the Background Art
In recent years, information utilizing the Internet has been extensively provided. Particularly, WWW (World Wide Web) has been frequently utilized as an information transmitting and receiving service in which images, voices, and so forth are integrated.
However, digital information, such as an image which is open to the public on a network of the Internet, can be easily copied by many and unspecified users. Therefore, some problems have arisen. For example, an image whose copyright is owned by a third person is secondarily utilized by making unauthorized copying thereof without the permission of the copyright owner. Further, also in expanding the business on the Internet using image-based contents, measures to prevent the unauthorized copying have been a problem. Therefore, the establishment of a technique for protecting the copyright of an image signal has been demanded.
An example of the measures conventionally known is an electronic watermark technique. The digital watermarking is a technique for embedding digital information in image data in a form that cannot be perceived by a human being.
Examples of the conventional electronic watermark technique include an electronic watermark technique using discrete wavelet transform described in an article entitled “Embedding a Signature to Picture under Wavelet Transformation” by Matsui, Onishi, Nakamura et al. (Journal of The Institute of Electronics, Information and Communication Engineers D-II VOL. J79-D-II, No. 6, pp. 1017 to 1024, June 1996) (hereinafter referred to as a technique by Matsui et al.).
The technique by Matsui et al. will be described with reference to
FIGS. 33
to
35
.
Description is now made of band division by discrete wavelet transform processing.
FIG. 33
is a block diagram showing an example of the structure of a conventional band dividing device
11
for division into three hierarchies. In
FIG. 33
, the conventional band dividing device
11
comprises first to third band dividing filters
100
,
200
and
300
having the same structure. Each of the first to third band dividing filters
100
,
200
and
300
divides a received image into four frequency bands, and calculates wavelet transform coefficients (hereinafter merely referred to as transform coefficients) for each of the frequency bands.
It is also possible to obtain transform coefficients even by sub-band division which is equivalent to the band division by discrete wavelet transform, which is not described herein.
The band dividing device
11
inputs a digitized image signal
71
into the first band dividing filter
100
. The first band dividing filter
100
divides the image signal
71
into signals in four bands, i.e., an LL
1
signal, an LH
1
signal, an HL
1
signal and an HH
1
signal (hereinafter generically referred to as a first hierarchical signal) on the basis of parameters of its horizontal and vertical frequency components. The second band dividing filter
200
receives the LL
1
signal in the lowest band in the first hierarchical signal, and further divides the LL
1
signal into an LL
2
signal, an LH
2
signal, an HL
2
signal and an HH
2
signal in four bands (hereinafter generically referred to as a second hierarchical signal). The third band dividing filter
300
receives the LL
2
signal in the lowest band in the second hierarchical signal, and further divides the LL
2
signal into an LL
3
signal, an LH
3
signal, an HL
3
signal and an HH
3
signal in four bands (hereinafter generically referred to as a third hierarchical signal).
FIG. 34
is a block diagram showing an example of the structure of the first band dividing filter
100
. In
FIG. 34
, the first band dividing filter
100
comprises first to third two-band division portions
101
to
103
. The first to third two-band division portions
101
to
103
respectively comprise one-dimensional low-pass filters (LPF)
111
to
113
, one-dimensional high-pass filters (HPF)
121
to
123
, and sub-samplers
131
to
133
and
141
to
143
for thinning a signal at a ratio of 2:1.
The first two-band division portion
101
receives the image signal
71
, and subjects the signal to low-pass filtering and high-pass filtering with respect to its horizontal component by the LPF
111
and the HPF
121
, respectively, to output two signals. The signals obtained by the low-pass filtering and the high-pass filtering are respectively thinned at a ratio of 2:1 using the sub-samplers
131
and
141
, and are then outputted to the subsequent stage. The second two-band division portion
102
receives the signal from the sub-sampler
131
, and filters the signal with respect to its vertical component by the LPF
112
and the BPF
122
, respectively, thins the signal at a ratio of 2:1 using the sub-samplers
132
and
142
, and then outputs two signals, i. e., an LL signal and an LH signal. On the other hand, the third two-band division portion
103
receives the signal from the sub-sampler
141
, and respectively filters the signal with respect to its vertical component by the LPF
113
and the HPF
123
, thins the signal at a ratio of 2:1 using the sub-samplers
133
and
143
, and then outputs two signals, i.e., an HL signal and an HH signal.
Consequently, four signals, i.e., the LL
1
signal which is low in both its horizontal and vertical components, the LH
1
signal which is low in its horizontal component and is high in its vertical component, the HL
1
signal which is high in its horizontal component and is low in its vertical component, and the HH
1
signal which is high in both its horizontal and vertical components, that is, transform coefficients are outputted from the first band-dividing filter
100
.
The second and third band dividing filters
200
and
300
also respectively subject received signals to the same processing as described above.
As a result of the band division processing by the first to third band dividing filters
100
,
200
and
300
, the image signal
71
is divided into
10
band signals, i.e., an LL
3
signal, an LH
3
signal, an HL
3
signal, an HH
3
signal, an LH
2
signal, an HL
2
signal, an HH
2
signal, an LH
1
signal, an HL
1
signal and an HH
1
signal.
FIG. 35
is a diagram showing representation of the signals by a two-dimensional frequency region.
In
FIG. 35
, the vertical axis represents a vertical frequency component, which increases as it is directed downward, and the horizontal axis represents a horizontal frequency component, which increases as it is directed rightward. Each of regions in
FIG. 35
is data serving as one image, and the area ratio of the regions coincides with the ratio of the respective numbers of data in the band signals. That is, in a case where the number of data in the LL
3
signal, the LH
3
signal, the HL
3
signal and the HH
3
signal which are the third hierarchical signal is taken as one, the number of data in the LH
2
signal, the HL
2
signal and the HH
2
signal which are the second hierarchical signal is four, and the number of data in the LH
1
signal, the HL
1
signal and the HH
1
signal which are the first hierarchical signal is
16
. Consequently, with respect to one data at the upper left of the LL
3
signal, for example, one data at the upper left of each of the LH
3
signal, the HL
3
signal and the HH
3
signal, four data, which are square, at the upper left of each of the LH
2
signal, the HL
2
signal and the H
Hatae Eiichi
Inoue Hisashi
Iwasaki Shiro
Katsura Takashi
Miyazaki Akio
Dang Duy M.
Johns Andrew W.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Apparatus for and method of embedding and extracting digital... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for and method of embedding and extracting digital..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for and method of embedding and extracting digital... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2980006