The invention provides a hierarchical method that is based on multi-scale computation
and motion-tracking algorithms to register images. A hierarchical registration
algorithm is used to address extrinsic and intrinsic variations. In particular,
a global similarity transformation is applied to align anatomical structures in
a global manner. Next, a local similarity transformation is applied to fine-tune
and adjust internal details. The registration output provides the input necessary
for other automated computations, such as volume and size comparisons and measurements.
