MultiPolygon

MultiPolygon is a type of label with several polygonal regions which contain same semantic information on an image. It’s often used for CV tasks such as semantic segmentation.

Each data can be assigned with multiple MultiPolygon labels.

The structure of one MultiPolygon label is like:

{
    "multiPolygon": [
        [
            {
                "x": <float>
                "y": <float>
            },
            ...
            ...
        ],
        ...
        ...
    ],
    "category": <str>
    "attributes": {
        <key>: <value>
        ...
        ...
    }
    "instance": <str>
}

To create a LabeledMultiPolygon label:

>>> from tensorbay.label import LabeledMultiPolygon
>>> multipolygon_label = LabeledMultiPolygon(
... [[(1.0, 2.0), (2.0, 3.0), (1.0, 3.0)], [(1.0, 4.0), (2.0, 3.0), (1.0, 8.0)]],
... category="category",
... attributes={"attribute_name": "attribute_value"},
... instance="instance_ID"
... )
>>> multipolygon_label
LabeledMultiPolygon [
  Polygon [...],
  Polygon [...]
](
  (category): 'category',
  (attributes): {...},
  (instance): 'instance_ID'
)

MultiPolygon.multi_polygon

LabeledMultiPolygon extends MultiPolygon.

To construct a LabeledMultiPolygon instance with only the geometry information, use the coordinates of the vertexes of polygonal regions.

>>> LabeledMultiPolygon([[[1.0, 4.0], [2.0, 3.7], [7.0, 4.0]],
... [[5.0, 7.0], [6.0, 7.0], [9.0, 8.0]]])
LabeledMultiPolygon [
  Polygon [...],
  Polygon [...]
]()

MultiPolygon.category

The category of the object inside polygonal regions. See category for details.

MultiPolygon.attributes

Attributes are the additional information about this object, which are stored in key-value pairs. See attributes for details.

MultiPolygon.instance

Instance is the unique id for the object inside of polygonal regions, which is mostly used for tracking tasks. See instance for details.

MultiPolygonSubcatalog

Before adding the MultiPolygon labels to data, MultiPolygonSubcatalog should be defined.

MultiPolygonSubcatalog has categories, attributes and tracking information, see common category information, attributes information and tracking information for details.

The catalog with only MultiPolygon subcatalog is typically stored in a json file as follows:

{
    "MULTI_POLYGON": {                                <object>*
        "description":                                <string>! -- Subcatalog description, (default: "").
        "isTracking":                                <boolean>! -- Whether this type of label in the dataset contains tracking
                                                                   information, (default: false).
        "categoryDelimiter":                          <string>  -- The delimiter in category names indicating subcategories.
                                                                   Recommended delimiter is ".". There is no "categoryDelimiter"
                                                                   field by default which means the category is of one level.
        "categories": [                                <array>  -- Category list, which contains all category information.
            {
                "name":                               <string>* -- Category name.
                "description":                        <string>! -- Category description, (default: "").
            },
            ...
            ...
        ],
        "attributes": [                                <array>  -- Attribute list, which contains all attribute information.
            {
                "name":                               <string>* -- Attribute name.
                "enum": [...],                         <array>  -- All possible options for the attribute.
                "type":                      <string or array>  -- Type of the attribute including "boolean", "integer",
                                                                   "number", "string", "array" and "null". And it is not
                                                                   required when "enum" is provided.
                "minimum":                            <number>  -- Minimum value of the attribute when type is "number".
                "maximum":                            <number>  -- Maximum value of the attribute when type is "number".
                "items": {                            <object>  -- Used only if the attribute type is "array".
                    "enum": [...],                     <array>  -- All possible options for elements in the attribute array.
                    "type":                  <string or array>  -- Type of elements in the attribute array.
                    "minimum":                        <number>  -- Minimum value of elements in the attribute array when type is
                                                                   "number".
                    "maximum":                        <number>  -- Maximum value of elements in the attribute array when type is
                                                                   "number".
                },
                "parentCategories": [...],             <array>  -- Indicates the category to which the attribute belongs. Do not
                                                                   add this field if it is a global attribute.
                "description":                        <string>! -- Attribute description, (default: "").
            },
            ...
            ...
        ]
    }
}

Note

* indicates that the field is required. ! indicates that the field has a default value.

To add a LabeledMultiPolygon label to one data:

>>> from tensorbay.dataset import Data
>>> data = Data("local_path")
>>> data.label.multi_polygon = []
>>> data.label.multi_polygon.append(multipolygon_label)

Note

One data may contain multiple MultiPolygon labels, so the Data.label.multi_polygon must be a list.