Frame Skeleton Based Auto-Inbetweening in Computer Assisted Cel Animation
Author(s): Konstantin Melikhov, Feng Tian, Hock Soon Seah, Quan Chen, Jie Qiu.
Proceedings: International Conference on Cyberworlds (CW'04), pp. 216--223, November,
2004.
[BibTeX] 
Abstract:
Automatic inbetweening is one of the main focuses in
computer assisted cel animation as inbetweening process
is traditionally time-consuming and labor-intensive in the
production of cartoon animation. Most previous work demand
either lots of modeling or working with complicated
programs and their interfaces, which do not take much animator’s
expertise into consideration, as animators are usually
more capable of drawing pictures on the paper than
programming with computer. An approach proposed in this
paper aims to provide an easy-to-use system which automatically
models key frames ”on the fly” and interpolates
them in several layers, including object size and position,
line curvatures and curve texture in order to preserve artistic
style of the hand-drawn key frames and make the motion
smooth and natural. Without much user interaction and
complicated program interface the system may be tuned, uploaded
into the Web so that not only professional artists but
those who are interested in cartoon but don’t have much
time or skill on drawing frames or inexperienced at using
computer, like students, free-lance animators, etc. may benefit
from using the system, for example, creating animation
clips for the Web. The results show that the algorithm works
well although it leaves areas for further research to extend
and improve the algorithm to work with as many different
types of key frames as possible.