Steps to Label
A labelling expert goes through the following steps to label an object. The Annotation Tool provides features to aid with various steps of labelling:
Interpolation (for a moving Obj.)
1. Scene Setup & Orientation
Setup point cloud visibility and density from Tool Settings (tool Footer).
Fit the entire point cloud in the viewing window using Fit to Screen (tool Header).
Jump to the centre (near the Ego vehicle) by using Jump to Origin (tool Header)
Toggle to Fullscreen if desired (tool Header).
2. Navigation in point cloud
Choose one of the two Navigation Controls to navigate in the point cloud based on your preference. (tool Header)
3. Object Identification
The tool provides multiple features & interactions that aid in object identification:
Expand and collapse the image Panel whenever needed to cross-check the object/scene-related details.
Use the help of the raycaster while navigating through the point cloud to see the respective coordinate highlighted in Camera Image(s).
On hovering on the Cameras, a red cone (Frustum) will appear in the point cloud emerging from the Ego vehicle to indicate the direction the camera is facing.
Enable the Merge Point Clouds across the frames to identify and mark stationary objects.
4. Object Visibility
For better object visibility during Drawing/ Marking use the following features:
Isolate areas of the point cloud where the object is present by marking a boundary to hide surrounding/ background points.
Hide points from bottom (ground) to top (ceiling) and vice-versa using the Ground & Ceiling Mover
5. Object Labelling
Identify the object either on the point cloud or on the camera sensors.
Pull up the Camera Sensors using the hotkey
Shift + Q
or double-clicking the camera sensor in the reference images.
Click the '+' icon on the Class the object belongs to from the Class List.
All the Drawing Tools linked to the Class will appear. Select the appropriate one from the Available Drawing Tools.
6. Annotation Detail Input
After marking the annotation, mark the annotation details in the popup that appears. Enter the Instance, Attribute Details and Relationship if any.
Attributes and Relationships
Once an annotation is created, the user needs to input the following:
a. Time-varying & Constant Attributes
Enter all the mandatory attributes (constant and time-varying).
b. Relationship
This tab is enabled if a relation has been defined in the recipe generator.
Select the the Relation type from the dropdown.
Select the Instance it has a relationship with (multiple instances can be added).
The relationship between the two can be applied across all frames or only the current frame.
The view icon allows the user to see the list of frames the relationship exists on.
Once the relationship is saved, the visual representation of the link is displayed over the point cloud with a line connecting the two instances.
Learn more about the Relationship feature.
Instance ID
An Instance ID is an identifier assigned to each labelled object across the batch of frames.
This instance ID can be used to track an object over multiple frames.
Instance ID can be viewed in the status box that appears on hover or selection of an annotation on the class list
Creating Instance
After creating an object, the user is asked to:
Create a new instance or select + Create New.
For example, only one object will have the ID car_1 which is present in Frame 1. This car could be present in 3 Cameras and the point cloud of Frame 1. Hence each of the 4 Sensors (3 Camera, 1 LiDAR) will have an annotation with ID car_1.
The Instance Dropdown allows 2 things:
Will allow the user to create New Instances
Lists all the created instances that are missing in that Sensor (car_48 in above eg.)
Changing Instance ID (for an Annotation across Frames)
Select the object.
Open the annotation details pop-up
Select + Create new'. The tool will allocate a new unique ID to it.
Save the new Instance ID. This replaces the old Instance ID in all frames for that annotation.
Merging Instance ID
If the user realises that two instances are the same object, then merging of instances is required. Eg. car_2
on Frame 10 is actually car_1.
Select the annotation you want to merge into another instance. (car 2 on Frame 10).
Right-click and select Annotation Details.
Open the instance ID dropdown. This dropdown has a lists of annotation IDs missing from that current frame and the option to create a new one.
Select the appropriate existing ID that the selected one needs to merge with (
car_1
).Save and the old instance gets changed to the new selected one (
car_1
becomescar_2
in Frame 10).
Merging instances is only possible when both instances have no overlapping Keyframes.
7. Dimension Setting/ Modification
On selecting an annotation, focus mode gets enabled on the Header. Click on this to view cuboids created in the point cloud from the top side and front views aiding accurate dimension modification.
Learn how to modify annotations using Shortcuts.
Learn how to use Drawing Tools.
8. Interpolation (for a moving Obj.)
If the Annotation created is for a moving object, use keyframe interpolation feature to mark the object across all the sequential frames without having to create it in every frame.
9. Object Tracking
Use this feature when an object is required to be labeled in both point cloud and image sensors while sharing a unique instance ID.
The projection of the created cuboid in the point cloud is visible on the appropriate camera images.
Double-click on that image to enlarge it.
Create a rectangle on that object.
Annotation detail input opens up. Choose the instance ID the same as its parent annotation created in the point cloud. Fill in the remaining details and Save.
The 2D Instance of the same object appears under the 3D Instance created on point cloud (sharing the same ID). Eg. Truck_1 is a cuboid annotation created in the point cloud and the instance of the same object is created in Image. This will appear as Truck_1 #2 (with a 2D icon on the left of the label)
10. Cross-Checking
Use the outlier feature to locate points that have not been labelled.
Use object clipping on the class row to identify if:
Any extra points have been labelled for an object
Or if required points have not been labelled for an object
Conduct auditing and mark issues that are observed in the Audit Tool
View the overall submissions of batches using the Visualization Tool.
Pull up the camera sensor
Shift + Q
, locate the object, pressEsc
to land in the point cloud in the same perspective as the camera sensor.
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