This paper describes a physically inspired method for the recovery of
the surface of 3D solid objects from sparse data. The method is based
on a model of closed elastic thin surface under the action of radial s
prings which can be considered as the analogous, in spherical coordina
tes, to the well-known thin plate model. The model is a representation
for whole-body surfaces which has the degrees of freedom for represen
ting fine details. We formulate the surface recovery problem as the pr
oblem of minimizing a non-quadratic energy functional. In the hypothes
is of small deformations, this functional is approximated with a quadr
atic one which is then discretized with the finite element method. We
provide steepest-descent-like algorithms both for the case of small de
formations and for that of large ones. Then we introduce a representat
ion of our model in terms of its free deformation modes. This represen
tation is extremely concise and is therefore suited for shape analysis
and recognition tasks. Finally, we report on the results of experimen
ts with synthetic and real data which show the performance of the meth
od (C) 1994 Academic Press, Inc.