PEDL87V21071-01
OKI Semiconductor
ML87V21071
•
Principles of Adaptive Noise Reduction
Adaptive noise reduction is achieved through the selection of noise reduction data, which utilizes the
correlative relationships between frames, fields, and lines for the pixels for which noise reduction is to be
performed, as shown in Figure F2-3 (3).
The distinguishing characteristics of each correlation are as shown below.
Between frames
: Same position (most effective), time difference 2V (less effective)
→Effective for still images (good NR, substantial afterimage)
: Position 0.5H different (effective), time difference 1V(effective)
→More effective for moving images than frames, more effective for still images than
lines (medium NR, medium afterimage)
Between fields
Between lines
: Position 1H different (less effective), time difference 0 (most effective)
→Effective for moving images, but not effective for edges (medium NR, no
afterimage, no NR for edges)
This IC detects motions and edges between lines, frames, and fields, based on the features described above, to
select data after better correlated NR and achieve effective noise reduction.
Time axis
2V
1V
1V
Direction of V
1H
: NR-target pixel
: NR
Figure F2-1 (3) Noise Reduction Correlation
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