Efficient description of shape perturbations

Airbus wish to have efficient ways of describing perturbations of a manu- factured aerofoil from its design shape. The typical kind of perturbations expected are waves, steps, and bumps, and automatic classification into the classes is desired. Various possible methods of analysis were pro- posed and studied in some detail, including projection onto suitable basis functions, wavelets, and radial basis functions. Other methods were studied in less detail, but with the aim of giving a digital signature of defects that could be used to classify them