Hi Francesco,

I don't think you want to do what you are trying to do. Specifically I don't see why you want to "register" the label field. Please note that in the parlance of CMTK and similar tools "register" means calculate the transform between two spaces *not* apply the transform to image data.

Once you have calculated a registration between sample and template greyscale stacks (using munger or directly using cmtk registration and cmtk warp) you will only need to use reformatx to convert your sample space label field into a template space label field.

For example

reformatx --outputtype "uint" --pv --floating -o

should do what you need. I am not sure if you need the output type argument but it shouldn't hurt.

Best,

Greg.