Cryptography Reference
In-Depth Information
Table 7.3.
Correct detection percentage.
Picture
Scheme
2 Mbps 4 Mbps 6 Mbps 8 Mbps
Walk
Motion-adaptive
98.0
84.2
99.6
100
Conventional
68.5
51.1
51.6
62.9
Flamingos Motion-adaptive
40.6
97.5
99.6
99.8
Conventional
12.1
94.4
98.9
99.6
Whale
Motion-adaptive
15.2
89.5
98.7
99.6
Conventional
12.7
88.8
96.9
98.7
Hall
Motion-adaptive
100
100
100
100
Conventional
99.6
100
100
100
Leaves
Motion-adaptive
11.8
90.2
94.0
97.1
Conventional
10.3
89.7
93.8
96.4
value was set to determine the bit value to zero (T = 0). The 64-bit
information was always detectable.
Step 5: Count the number of frames in which the information was detected
correctly.
This procedure was done for each of the four MPEG-2 bit rates (2, 4, 6,
and 8 Mbps).
Results
The results are summarized in Table 7.3, which lists the percentages of the
450 frames from which information was detected correctly. That is the correct
detection rates. The percentages for incorrect detection was 100 minus the
listed values. These are the false-negative error rates.
For Walk, Flamingos, and Whale, each has both static and motion areas.
The motion-adaptive technique improved the detection rates at all four bit
rates and especially that at 2 Mbps. For Hall and Leaves, the motion-adaptive
technique negligibly improved the detection rates. This is because most parts
of the frames in these pictures are either static or moving. As described in
Sect. 7.3.4, the motion-adaptive technique was also comparatively ineffective
in improving the picture quality of watermarked pictures when WMs could not
be preferentially readily allocated to motion areas. These detection reliability
results correspond to the results obtained by subjective evaluation of picture
quality.
The motion-adaptive embedding technique gave better detection rates for
all of the evaluated pictures and yielded an average improvement of 9.5%. The
motion-adaptive embedding technique thus improves watermark durability.
