discretization strategies used). From the large body of literature on the subject,
it was recently concluded [35] that the currently popular mutual-information-
based methods are suitable for numerous clinical applications, but that they may
not be a universal cure for all registration problems. Also, specific implementation
choices may have a large influence on the results.
In biological imaging, image registration methods are less common than in
clinical medical imaging, but a variety of techniques are increasingly used in both
3-D and time-lapse microscopy. For tracking leukocytes in phase-contrast images,
for example, normalized cross-correlation of edge information has been used to
achieve translational background registration [22, 29, 30]. By