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Locally-accurate motion estimation
for object-based video coding
M.K. Steliaros
& G.R. Martin & R.A.
Packwood.
SPIE Proceedings of Visual Communications and Image
Processing,
Vol. 3309, January 1998, pp 306-316.
We describe new motion coding algorithms that develop
Fixed Size Block Matching (FSBM) into Variable Sized Block Matching (VSBM)
and a modified approach (MVSBM) which can exploit irregularly shaped areas
of uniform motion. New generations of video coding standards handle arbitrary
shaped visual objects as well as frame based input. We explain how MVSBM
strategies work when combining shaped data and block based algorithms.
Locally accurate motion information is produced by the combination of otherwise
ambiguous estimates produced by the small area matching required to detect
locally diverse movements. The success of various prediction strategies
indicates that the motion information is well behaved and thus likely to
be accurate, given complex natural image sequence source material. MVSBM
is evaluated by forcing it to perform with the same quality prediction
as FSBM, then comparing the number of bits required by each technique.
FSBM vector coding methods are taken from H.263 and MPEG-4 for comparison
with those developed for MVSBM, extra compression phases are developed
for MVSBM by utilising the greater structure of the representation. Results
are presented for three MEPG-4 test sequences, ``Container'', ``Weather''
and ``Stefan''. We show bit savings of 67% bits for ``Container'', and
13% for ``Stefan'' with more complex object activity.
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