Point-Based Elastic Registration of Medical Image Data Using Approximating Thin-Plate Splines

We consider elastic registration of medical image data based on thin plate splines using a set of corresponding anatomical point land marks Previous work on this topic has concentrated on using interpola tion schemes Such schemes force the corresponding landmarks to exactly match each other and assume that the landmark positions are known exactly However in real applications the localization of landmarks is always prone to some error Therefore to take into account these local ization errors we have investigated the application of an approximation scheme which is based on regularization theory This approach generally leads to a more accurate and robust registration result In particular outliers do not disturb the registration result as much as is the case with an interpolation scheme Also it is possible to individually weight the landmarks according to their localization uncertainty In addition to this study we report on investigations into semi automatic extraction of anatomical point landmarks