Scalabel Format

Scalabel format defines the protocol for importing image lists with optional automatic labels and exporting the manual annotations. This is also the format for BDD100K dataset.

Schema of the format is shown below. Most of the fields are optional depending on your purpose. If you only want to upload a list of images when creating a project, you only need url. videoName is used to group frames for each tracking task. If you are annotating bounding boxes, you can ignore poly2d and other label types.

- name: string
- url: string
- videoName: string (optional)
- attributes: a dictionary of frame attributes
- intrinsics
    - focal: [x, y]
    - center: [x, y]
    - nearClip:
- extrinsics
    - location
    - rotation
- timestamp: int64 (epoch time ms)
- frameIndex: int (optional, frame index in this video)
- labels [ ]:
    - id: string
    - category: string (classification)
    - manualShape: boolean
    - manualAttributes: boolean
    - score: float
    - attributes: a dictionary of label attributes
    - box2d:
        - x1: float
        - y1: float
        - x2: float
        - y2: float
    - box3d:
        - alpha:
        - orientation:
        - location: ()
        - dimension: (3D point, height, width, length)
    - poly2d: an array of objects, with the structure
        - vertices: [][]float (list of 2-tuples [x, y])
        - types: string
        - closed: boolean

More details about the fields

  • labels

    • manualShape: whether the shape of the label is created or modified manually

    • manualAttributes: whether the attribute of the label is created or modified manually

    • score: the confidence or some other ways of measuring the quality of the label.

    • box3d

      • alpha: observation angle if there is a 2D view

      • orientation: 3D orientation of the bounding box, used for 3D point cloud annotation

      • locatoin: 3D point, x, y, z, center of the box

      • dimension: 3D box size

    • poly2d

      • types: Each character corresponds to the type of the vertex with the same index in vertices. ‘L’ for vertex and ‘C’ for control point of a bezier curve.

      • closed: true for polygon and otherwise for path