Cryptography Reference
In-Depth Information
P[y(i;j) = 255] = A=255
(13.5)
P[y(i;j) = 0] = (255 A)=255
(13.6)
such that
E[y(i;j)] = 0 P[y(i;j) = 0] + 255 P[y(i;j) = 255]
= 0 (255 A)=255 + 255 A=255
= A
(13.7)
Typically, the percentages of white and black pixels in X are A=255 100%
and (255A)=255100% respectively, distributed evenly in X. In a way, one
can argue that
P[y(i;j) = 255jx(i;j)] = x(i;j)=255
(13.8)
such that
E[y(i;j)jx(i;j)] = x(i;j)
(13.9)
Another common error diffusion kernel is the Jarvis kernel [5]
2
3
7
5
1
48
4
5
3
5
7
5
3
1
3
5
3
1
FIGURE 13.2
Original multitone "Lena" (X).
 
 
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