30-05-2013, 02:46 PM
DPCM - Overview
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Signal distortions due to
intraframe DPCM coding
Granular noise: random
noise in flat areas of the
picture
Edge busyness: jittery
appearance of edges
(for video)
Slope overload: blur of
high-contrast edges,
Moire patterns in periodic
structures.
Interframe coding of video signals
Interframe coding exploits:
similarity of temporally successive pictures
temporal properties of human vision
Important interframe coding methods:
Adaptive intra-interframe coding
Conditional replenishment
Motion-compensated prediction
Motion-compensated interpolation
DPCM - Summary
DPCM: Prediction from previously coded/transmitted samples (known at
transmitter and receiver)
Typical signal distortions for intraframe DPCM: granular noise, edge
busyness, slope overload
Adaptive Intra-Interframe-DPCM: forward adaptation vs. backward
adaptation
Conditional replenishment: only transmit frame-to-frame changes
Temporal noise reduction by nonlinear, recursive frame differencing