PEDL87V21071-01
OKI Semiconductor
ML87V21071
2.3 Edge-Adaptive 2D Noise Reduction
This IC has an edge-adaptive 2D noise reduction function that reduces residual noise after input type SNR
processing and block noise and mosquito noise that occur due to compression such as MPEG.
2.3.1 Luminance Edge-Adaptive 2D Noise Reduction
By setting YLPFON (SUB:64h-bit[0]) = 1, 2D noise reduction of luminance data operates.
The edge-adaptive 2D noise reduction uses the surrounding 6 pixels (YHLPFM = 0) centering on the target pixel
that is selected by YHLPFM (SUB:64h-bit[2]) or surrounding 10 pixels (YHLPFM = 1) centering on the target
pixel (Figure 2-3-1) to form a filter with two-stage configuration (that is, vertical direction filter and horizontal
direction filter), thereby achieving noise reduction.
The filter coefficient can be selected through YLPFM (SUB:64h-bit[1]).
[Vertical direction filter value processing]
YLPFM=0:f(z) = (7/8)z0+(1/8)z+1
YLPFM=1:f(z) = (3/4)z0+(1/4)z+1
[Horizontal direction filter value processing (YHLPFM=0)]
YLPFM=0: f(z) = (1/8)z-1+ (3/4)z0+(1/8)z+1
YLPFM=1: f(z) = (1/4)z-1+ (1/2)z0+(1/4)z+1
[Horizontal direction filter value processing (YHLPFM=1)]
YLPFM=0: f(z) = (1/16)z-2+(1/16)z-1+(3/4)z0+(1/16)z+1+(1/16)z+2
YLPFM=1: f(z) = (1/8)z-2+(1/8)z-1+(1/2)z0+(1/8)z+1+(1/8)z+2
As a countermeasure for band deterioration of edge sections, the difference between the target pixel (z0) and
surrounding pixels (z-2, z-1, z+1, z+2) is compared with YED[4:0] (SUB:65h-bit[4:0]). When the difference
exceeds YED[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.
V_average
V_average
V_average
V_average
V_average
: Target pixel to be averaged
: Edge detection
Y01
Y02
Y03
Y04
Y05
: Not used when 3 pixels are
averaged
Y11
Y12
Y13
Y14
Y15
H_average
YV11
YV12
YV13
YV14
YV15
YH13
Figure F2-3-1 Luminance Edge-Adaptive 2D Noise Reduction
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