Robust Estimation in Deformation Models

Robust estimation methods are presented and applied, together with the conventional least squares procedure, to typical deformation models. The comparison of the results shows that the least squares method yields biased and in unfavourable situations even useless estimates if the mathematical model does not account for existing single-point displacements. A procedure of repeated testing and estimation is required to arrive at reasonable results. If in the same situation robust estimators are employed the final and complete result is attained unbiasedly in a single estimation step. A reliable separation of single-point displacements and the general deformation model is achieved without difficulties.