SpaceTime Surface Simplification and Edgebreaker Compression for
2D Cel Animations 



Digitized cell animations
are typically composed of frames, which contain a small number of regions,
which each contain pixels of the same color and exhibit a significant level
of shape coherence through time. To exploit this coherence, we treat the
stack of frames as a 3D volume and represent the evolution of each region
by the bounding surface of the 3D volume V that it sweeps out.
To reduce transmission costs, we triangulate and simplify the bounding surface
and then encode it using the Edgebreaker compression scheme. To restore
a close approximation of the original animation, the client player decompresses
the surface and produces the successive frames by intersecting
V with constanttime planes. The intersection is generated in realtime
with standard graphics hardware through an improved capping (i.e. solid
clipping) technique, which correctly handles overlapping facets. We have
tested this approach on real and synthetic black&white animations and
report compression ratios that improve upon those produced using the MPEG,
MRLE, and GZIP compression standards for an equivalent quality result.


Related publications: SpaceTime Surface Simplification and Edgebreaker Compression for 2D Cel Animations Vivek Kwatra and Jarek Rossignac International Journal on Shape Modeling, Volume8, Number 2, December 2002 Paper  BibTex Surface Simplification and Edgebreaker Compression for 2D Cel Animations Vivek Kwatra and Jarek Rossignac Proc. International Conference on Shape Modelling and Applications (SMI 2002) Paper  Presentation  BibTex 

Overview: Results: Videos: Compressed sizes and ratios (comparison with other techniques): Compression ratios (comparison graph): 