Information Technology Reference
In-Depth Information
=10
−
3
and
Table 1.
Minimum values of WM lengths
N
to guarantee
P
m
=
P
fa
parameters
α
,
σ
C
providing corresponding values for several filter attack parameter
δ
Image
fishingboat
Case O
ασ
ε
η
:
N
5 5 2.000 : 38
Case A
Case B
Case C
δασ
ε
η
:
N
0.75 5 6 1.787 : 101
1.00 5 7 2.124 : 220
1.25 5 7 2.062 : 320
δα
ε
η
:
N
0.75 8 6 1.796 : 68
1.00 12 7 2.159 : 87
1.25 16 7 1.927 : 82
δα
ε
η
:
N
0.75 8 11 2.066 : 124
1.00 12 17 2.087 : 169
1.25 16 22 1.942 : 175
Image
lena
Case O
ασ
ε
η
:
N
7 6 1.735 : 29
Case A
Case B
Case C
δασ
ε
η
:
N
0.75 7 8 1.653 : 89
1.00 7 9 1.817 : 190
1.25 7 9 1.755 : 281
δα
ε
η
:
N
0.75 12 9 1.796 : 70
1.00 17 9 1.792 : 77
1.25 22 9 1.691 : 73
δα
ε
η
:
N
0.75 12 15 1.738 : 102
1.00 17 22 1.755 : 143
1.25 22 29 1.789 : 156
(a) Cover image
fishingboat
be-
fore watermarking attack.
(b) Cover image
fishingboat
after
watermarking and filtering at-
tack with
δ
=0
.
75 and
η
=1
.
79.
Fig. 1.
Cover image and its watermarked and attacked image
(a)-(b) that the visual effect of filtering, even for filter parameter
δ
= 1 is still
acceptable.
If WM is a colored noise sequence (as in Case B) we can observe an improve-
ment of the WM system (the required
N
decreases in comparison with Case A).
The Case C, when both
W
and
ε
are colored noise sequences, is observed to be
inferior than Case B.
