Volume 92, Issue 1, January 2012, Pages 1480-1491

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Source:

Signal Processing.
Volume 92, Issue 1,

January 2012, Pages 1480
-
1491


Authors:

Sanjay
Rawat
,
Balasubramanian

Raman.


Speaker:
Chi
-
Hsien

Lin

Date:
2012/03/28


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1


Introduction


Proposed Scheme


Experimental Results


Conclusions


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2

:Master Share

: Ownership Share

FrFT

SVD

Certified
Authority

2012/3/28

3

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4

(a)Original image. (b)
FrFT

(1/2,1/2). (c)
FrFT

r(3/2,5/2).
(d)
FrFT

(3/2,5/2). (e)
FrFT

(1/2,1/2
).

(f)
FrFT
(1/2,2).

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5

(a)
Original image
.(
b)
FrFT

(
3/2,1/2).(
c)
InverseFrFT

(
3/2,1/2
).
(d)
InverseFrFT

(3/2,1/2
). (e)Inverse
FrFT


(3/2,1/2
).
(
f)
InverseFrFT

(3/2,1/2
).

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6


=3/2,



=
-
1/2


=
-
3/2,



=1/2

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7


Notations



H : host image
MxN

(grayscale image)


S : secret image
mxn

(binary image)


Ms : mater share 2mx2n (binary image)


Os : ownership share 2mx2n (binary image)


X
av

: the average value of all pixels in X.

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8

Hostimage

H

2.Select
mxn

blocks,
using PRNG

secret key
K.


FrFT

SVD

X
ij

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9

X=[
X
ij
]
mxn

Divide the master share into non
-
overlapping 2x2
blocks

Ms=

m
ij
=

if
B
ij
=1

if
B
ij
=0

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10

Divide the ownership share into non
-
overlapping 2x2
blocks

Os=

O
ij
=

if
B
ij


S
ij
=0

if
B
ij


S
ij
=1

Certified
Authority

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11

Mater share

construction

The suspected image H’

Master Share M’

Certified
Authority

Ownership Share
O’

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12

Reduced
screte

image S

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14

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15

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16

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20

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21

[20]
C.S.Hsu
,
Y.C.Hou
, Copyright protection scheme for digital images using visual cryptography and
sampling methods, Optical Engineering 44(2005)077003.


[23]
M.S.Wang
,
W.C.Chen
, A hybrid DWT
-
SVD copyright protection scheme based on k
-
means
clustering and visual cryptography, Computer Standards & Interfaces31(2009)757

762.

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22


The host image is not modified by
embedding the watermark .



It is based on visual cryptography, which can
recover the secret image with human eyes.




The transform order of
FrFT

are used as keys.


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