In image processing, "motions by curvature" provide an efficient way to
smooth curves representing the boundaries of objects. In such a motion,
each point of the curve moves, at any instant, with a normal velocity
equal to a function of the curvature at this point. This book is a
rigorous and self-contained exposition of the techniques of "motion by
curvature". The approach is axiomatic and formulated in terms of
geometric invariance with respect to the position of the observer. This
is translated into mathematical terms, and the author develops the
approach of Olver, Sapiro and Tannenbaum, which classifies all curve
evolution equations. He then draws a complete parallel with another
axiomatic approach using level-set methods: this leads to generalized
curvature motions. Finally, novel, and very accurate, numerical schemes
are proposed allowing one to compute the solution of highly degenerate
evolution equations in a completely invariant way. The convergence of
this scheme is also proved.