OPT: now allow different size of input and output
OPT: now allow different size of input and output

Former-commit-id: 75d7e8ab893ce3fc6f6b2acc59183754010b4186 [formerly e88e229e7adb6cd8c1bcf126ff3b74b4e517b098]
Former-commit-id: 6ed736937a302eb8cce496237e22d448e6b740b9
Former-commit-id: 43877638431b73ca41eae4d84266b756972518d6
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox