Two new similarity measures for rigid image registration, based on
the normalization of Jensen's difference applied to Renyi and
Tsallis-Havrda-Charvat entropies, are introduced. One measure is
normalized by the first term of Jensen's difference, which in our
proposal coincides with the marginal entropy, and the other by the
joint entropy. These measures can be seen as an extension of two
measures successfully applied in medical image registration: the
mutual information and the normalized mutual information.
Experiments with various registration modalities show that the new
similarity measures are more robust than the normalized mutual
information for some modalities and a determined range of the
entropy parameter. Also, a certain improvement on accuracy can be
obtained for a different range of this parameter.