yolov5 라벨 시각화
└─*any location*
├─images
│ └─*name*.jpg -> source file
└─labels
└─*name*.txt -> source file
└─*any location*
*name*.yaml -> header file
label file format : *name*.txt
header file format
train: ../train/images
val: ../valid/images
nc: 2
names: ['mask', 'no-mask'] -> required field