The spherical deformation model

Miller et al. (1994) describe a model for representing spatial objects with no obvious landmarks.Each object is represented by a global translation and a normal deformation of a sphere.The normal deformation is defined via the orthonormal spherical.harmonic basis.In this paper we analyse the spherical deformation model in detail and describe how it may be used to summarize the shape of star.shaped three.dimensional objects with few parameters.It is of interest to make statistical inference about the three.dimensional shape parameters from continuous observations of the surface and from a single central section of the object.We use maximum.likelihood.based inference for this purpose and demonstrate the suggested methods on real data.