detects 3 lines robustly
detects 3 lines robustly


Former-commit-id: 2999db2c7b6d088a2ce3196c7e2a39b5e7d6073b
Former-commit-id: 63fc1a39cddf50c97e63807ddb9fd9348ddba216
tourdrone/cvdrone,tourdrone/cvdrone