1. A computer implemented method of building a statistical shape model by automatically establishing correspondence between a set of two-dimensional shapes or three-dimensional shapes, the method comprising: (a) determining a parameterization of each shape, building a statistical shape model using the parameterization, using an objective function to automatically provide an output which indicates a quality of the statistical shape model, wherein the output of the objective function is a measure of the quantity of information required to code the set of shapes using the statistical shape model; (b) performing step (a) repeatedly for different parameterizations and comparing the quality of the resulting statistical shape models using output of the objective function to automatically select a parameterization based upon said output of the objective function; and (c) outputting the selected statistical shape model.