Further research is needed on the optimum selection of landmarks and the analysis of the evolutionary hypothesis, as well as analysis without using landmarks. These are two-dimensional problems and their extension to three dimensions would be extremely useful in Anatomy and Anthropology. There are many unresolved problems in this area such as the behaviour of maximum likelihood estimators and predictors, and diagnostic tools. There are strong connections between kriging predictors for the spatial linear model and spline methods of interpolation and smoothing. Robustness One of the classic problems of robustness theory involves the simultaneous estimation of location and scatter from a set of multivariate data.
More work is needed to better understand questions of influence, uniqueness, and breakdown.
A classic class of estimators used in multivariate robustness is the class of M-estimators. A new class of estimators called constrained M-estimators overcomes these theoretical problems at the price of being more difficult to compute in practice. More work is needed to understand and fine-tune the behaviour of these estimates. There are many opportunities for research in medical imaging. The individual projects usually originate in departments which specialize in various branches of medicine and are associated with the Leeds General Infirmary or St James' Hospital in Leeds.