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Advances in Visual Data Compression and Communication
book

Advances in Visual Data Compression and Communication

by Feng Wu
July 2014
Intermediate to advanced content levelIntermediate to advanced
513 pages
16h 40m
English
Auerbach Publications
Content preview from Advances in Visual Data Compression and Communication
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158 8 Directional DCT Transform
For a given direction angle θ unequal to zero as shown in Figure 8.2b, the first
type of directional primary operation with a parameter α from one pixel to another
is defined in Z domain as
O(X [n
i
],X [n
j
],θ ,α) =
X ←−
1
1
1
1
1
αF(θ) 1
1
1
X
, (8.6)
where n
i
= n
5
and n
j
= n
2
in the case illustrated in Figure 8.2b. F(θ ) is the function
of shifting and interpolation in Z domain and locates at the n
i
-th row and the n
j
-th
column of operation matrix. It is defined as
F (θ ) = Z
−|n
i
n
j
|tan(θ)
. (8.7)
If |n
i
n
j
|tan(θ) is an integer, F(θ) only means a left shifting of |n
i
n
j
|tan(θ)
pixels; otherwise the interpolation is needed and F(θ) is redefined as
F(θ ) =
k
w
k
z
k
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Publisher Resources

ISBN: 9781482234138