Class labels

How to add label classes and define an ontology for an annotation task

You can create an ontology and add labels to a task either when creating it or editing it. Note that you cannot delete an existing label or attribute.

If you already have the labels defined in another task, you can also copy those when setting up labels for a new task. Simply select the task from which you would like to copy labels.

When creating a label, you can specify its Name and color, and add attributes of various types.

Once a task has been created, labels and attributes cannot be deleted. However they can be edited and more labels/attributes can be added from the Labels tab on the task page.

Basic settings

Color You can set the color of the class by clicking on the color box to the left of the label name

Class order To set the order in which labels should appear on the annotation screen, hold the drag icon to left of a label's row and drag it into the right position.

Track Turn this on if you want to track objects of this class across frames, with consistent ID and automatic interpolation.

Mark as Instance label By default a label is set as a semantic label. If a class is an Instance class, check this to mark it as instance. Note that this only has an effect if you are using the classes to label with polygons. Otherwise it is ignored.

Default Dimensions (Lidar only) Set the default dimensions of this object. Once this is set, whenever you place a cuboid of this label on a point cloud, it will be of this size.

Lock Dimensions (Lidar only) If you are tracking an object across frames and want its dimensions to stay consistent throughout its lifetime, set this to true. This will make sure any time you make a change to the object's size in any frame, it will be copied to all other frames automatically.

Class attributes

You can add attributes of the following types to a label:

1. Select - Adds a dropdown with multiple options from which a single value can be chosen.

2. Text - Add a box to allow user to enter free-form text. This can be used for small text entries like license plates as well as for longer form entries for OCR use-cases.

3. Number - Add a box to allow user to enter any numerical value.

4. Radio button - Adds a group of radio buttons from which a single value can be chosen.

5. Checkbox - True or False type value.

Further, each attribute can be marked as Mutable and Required.

1. Mutable - Only applies to Tracks. If checked, this allows the attribute values to change from frame to frame for the same object. For example, a car can be occluded or not occluded in different frames, so its Mutable property should be set to True. Other attributes however, such as License plate, type of car, color etc. are unique to the object, so their Mutable property should be set to False.

2. Required - Set this to true if you want to set a validation check to ensure the labeler has set an appropriate value to the attributes. If an annotation fails this test, it will be highlighted in red on the annotation page.

If an attribute is marked required, and it has not bee set by the labeler, it will be highlighted in red.