  This paper presents a novel method for identifying indentations on the
boundary of solid 2D shape. It uses the signed curvature at a set of points
along the boundary to identify indentations and provides one parameter for
tuning the selection mechanism for discriminating indentations from other
boundary irregularities. An efficient implementation is described based on the
Fourier transform for calculating curvature from a sequence of points obtained
from the boundary of a binary blob.
