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

Former-commit-id: 6460985e937d5e9711460799a4e9e143e10619bf
Former-commit-id: a4d5e623819ed4f25aa9db69310510b451556045
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox