This paper describes various methods in abstract ways that
can be used for image morphing.
It is mainly divided into description of mesh morphing
algorithms and time transition control.
For morphing, it describes simple cross-dissolving,
mesh morphing (using non overlapping corresponding polygons),
field morphing (using corresponding pairs of lines,
radial basis functions (specifying features by a set of points),
energy minimization, multilevel free-form deformation,
and work minimization.
For transition control, it describes how nonuniform transition
from part to part can give new dramatic events.
This paper gives a good idea on what image morphing methods
are out there but doesn't give detailed enough descriptions
on each of the methods.