OPT: detect_vertebral_levels: adjusted params
OPT: detect_vertebral_levels: adjusted params

Former-commit-id: 72b73c22beab46c47ccef896845451cad560fbe2
Former-commit-id: decb5235b3fca2467ce6d7594101097a70f96bc9
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox