PEDL87V21071-01
OKI Semiconductor
ML87V21071
2.3.2 Chrominance Edge-Adaptive 2D Noise Reduction
By setting CLPFON(SUB:64h-bit[3]) = 1, edge-adaptive 2D noise reduction of chrominance data can be
operated.
Chrominance edge-adaptive 2D noise reduction uses the surrounding 3 pixels skipping in the horizontal direction
(Figure 2-3-2) and centering on the target pixel and forms only a horizontal direction filter, thereby achieving
noise reduction.
The filter coefficient can be selected through CLPFM (SUB:65h-bit[4]).
This IC allows the setting of a compensation level of the edge section through the CED[4:0] (SUB:66h-bit[4:0])
level to prevent band deterioration of the edge section by LPF.
However, if edge compensation is enhanced, edge-adaptive 2D noise reduction deteriorates.
[Horizontal direction filter processing]
CLPFM=0: f(z) = (1/8)z-2+(3/4)z0+(1/8)z+2
CLPFM=1: f(z) = (1/4)z-2+(1/2)z0+(1/4)z+2
As a countermeasure for band deterioration of edge sections, the difference between the target pixel (z0) and
surrounding pixels (z-2, z+2) is compared with CED[4:0] (SUB:66h-bit[4:0]). When the difference exceeds
CED[4:0], the section is determined as an edge section and adaptive processing is performed using the edge
adaptation method that replaces the surrounding pixel section in filter processing with the target pixel and
removes the data from the filter data.
: Filtering-target pixel
: Edge detection
H_filter
CH13
CV11
CV12
CV13
CV14
CV15
Figure F2-3-2 Chrominance Edge-Adaptive 2D Noise Reduction
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