Iterative procedures for reduction of blocking effects in transformimage coding
Zakhor, A.
Circuits and Systems for Video Technology, IEEE Transactions on
Volume 2, Issue 1, Mar 1992 Page(s):91 - 95
Digital Object Identifier 10.1109/76.134377
Summary:The authors propose an iterative block reduction technique based
on the theory of a projection onto convex sets. The idea is to impose a
number of constraints on the coded image in such a way as to restore it
to its original artifact-free form. One such constraint can be derived
by exploiting the fact that the transform-coded image suffering from
blocking effects contains high-frequency vertical and horizontal
artifacts corresponding to vertical and horizontal discontinuities
across boundaries of neighboring blocks. Another constraint has to be
with the quantization intervals of the transform coefficients.
Specifically, the decision levels associated with transform coefficient
quantizers can be used as lower and upper bounds on transform
coefficients, which in turn define boundaries of the convex set for
projection. A few examples of the proposed approach are presented
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