Table 2. Listing of the registration parameters used in the nonlinear model-building process.

Step size (mm)	Iterations	Gaussian Blur (mm)
8	30	16
8	30	8
4	30	8
4	30	4
2	10	4
2	10	2

At each stage, the intensity-blurred images were matched to one another. A 3D simplex optimization was used with stiffness, weight, similarity parameters set to 1, 1, and 0.3 respectively (as optimized in [41]). In each case the spherical search area around each node was set to 3 x step size.