For the metric “ANTSNeighborhoodCorrelationImageToImageMetricv4”, we can set up the radius of the neighborhood by SetRadius(). I wonder if the radius is defined on physical space or image space? i.e. the unit is mm or voxel?
Thanks!
Hi Ray,
In ITK, Radius is a common term used to refer the size of local neighborhoods, and it is given in voxel units. It can be anisotropic, and the size in a given direction is 2 * radius[i] + 1. The + 1 is for counting the center voxel.
Hope this helps,
Matt
Thank you Matt!
What if we do multi-resolution registration? Say the shrinking factor is 2x1, and the radius is set to be 4. The voxel spacing is 1mmx1mmx1mm. At the second level, the radius is still 4 VOXELs, which means the actual radius at that level is 8 MMs?
-Ray
correct.