Information Technology Reference
In-Depth Information
20
18
16
14
12
10
8
6
4
2
0
65
70
75
80
85
90
95
100 105
J
PG quality %
Fig. 4.
Plot of the dependence between the quality of steganography noisy channel (distorted by
JPEG
1 of different quality) added intentional distortion (
JPEG
2) for segmentation blocks of
size
8
×
8
and BER
Source
100
90
80
Fig. 5.
Plot of the dependence between the quality of steganography channel (distorted by
JPEG
1) added intentional distortion (
JPEG
2) for segmentation blocks of size
12
×
12
and BER
While comparing the plots presented in Fig. 4 and in Fig. 5, one can see that the re-
sult of collateral effects of the noisy channel and intentional distortion is nonlinear.
Indeed, the averaged BER value resulted from the steganography channel distortion,
say, corresponding to 80% quality
of
JPEG
compression, is significantly less than
BER corresponding to application of two
JPEG
compressions (channel noise and
intentional distortion) both of quality 90%. One more observation resulted from the
simulation is that the detrimental effect of the intentional distortion (second
JPEG
) on
the embedded information decreases with the increase of the block size.