Add Path type option for Resample target argument (Issue #132)

[GFabien]

Change Resample transform to accept an external reference image as a Path object. Convenient when all samples have to be resampled to a given template. (see #132)

Usage:

from pathlib import Path
import torchio
from torchio.transforms import Resample

transform = Resample(Path('template.nii.gz'))
subject = torchio.Subject(t1=torchio.Image('t1.nii.gz', torchio.INTENSITY))
dataset = torchio.ImagesDataset([subject], transform=transform)

[fepegar]

Hi again, @GFabien. I think it's not a good idea to make a decision based on whether the argument is of type str or Path, as paths are still most often given as strings nowadays.

I think the way to go is passing a key name to the transform (as I suggested here). If the value for that key is an Image, that is the reference. If it's a str/Path, that image will be loaded and used as reference.

What do you think?

[GFabien]

Ok I think I misunderstood your point. I totally agree with you, here is my new suggestion.

[fepegar]

Thanks again @GFabien!

[fepegar]

@all-contributors please add @GFabien for code

[allcontributors]

@fepegar

I've put up a pull request to add @GFabien! 🎉