OPT: optimized smoothing calculation and correct the physical dimension of the window
OPT: optimized smoothing calculation and correct the physical dimension of the window

Former-commit-id: 10316bf8055541973c8070aa212d94ff0155cb06 [formerly 42d449048f3c470cbce0d44804d59bbea385811a]
Former-commit-id: cf233686b801c00c10223a4e6bd4b0549e89a34f
Former-commit-id: acd8a754441097c625f17437d2d69acbff8f2da3
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox