There have been some studies done on high dimensional image registration using \alpha-MI (Staring et al, 2009). The implementation of alpha-Mutual Information is available in elastix: http://elastix.isi.uu.nl/doxygen/classitk_1_1KNNGraphAlphaMutualInformationImageToImageMetric.html. However, is it possible to employ \alpha-MI to register multimodal images which have a different number of feature components? Is it the limitation of \alpha-MI which requires images to have the same number of channels? Can a new metric be developed for such case?