Object tracking
Object tracking follows instance labels through a series of frames in a video or image sequence.
By detecting and localizing objects in a frame, their position in subsequent frames is determined based on pixel information enclosed within the label boundary. All labels automatically created using interpolation are assigned a confidence score (α) of 99%.
Note
Your video or image sequence's pixel information is accessed by Encord.
Since tracking algorithms propagate labels forward through frames, object tracking works if labels are made on lower number frame (for example, near the start of the video).
Note
Object tracking and interpolation are both techniques to automatically apply labels on a range of frames.
- Interpolation applies labels in between reference labels.
- Object tracking uses a single existing label and applies labels to frames following manual reference labels.
Ontologies
Ontology shape | Interpolation | Tracking |
---|---|---|
Bounding box | ✅ | ✅ |
Rotatable bounding box | ✅ | ✅ |
Polygon | ✅ | ❌ |
Polyline | ✅ | ✅ |
Primitive | ✅ | ✅ |
Keypoint | ✅ | ✅ |
Bitmask | ✅ | ❌ |
* Polygon and Bitmasks use auto-segmentation tracking
Quick object tracking
- Create at least one instance label on the frame you want to start tracking the instance from.
Tip
More manual instance labels result in high object tracking accuracy.
- Click the icon on the instance to be tracked, and click Track from this frame.
- Object tracking is run for 30 consecutive frames, starting at and including the frame currently being viewed.
Keyboard shortcut
You can use keyboard shortcuts to run object tracking.
- Click the instance label.
- Use the Shift + T keyboard shortcut to the run object tracking for 30 frames.
Fine tune object tracking
- Create at least one instance label on the frame you want to start tracking the instance from.
Tip
More manual instance labels result in high object tracking accuracy.
-
Click the Automated labelling button in the bottom left corner of the Label Editor to bring up options for automated labeling.
-
The Tracking and interpolation section is open by default.
- Under the Method heading, select Tracking.
- Select the object instance you want to track.
- The Tracking annotation interval lets you specify how many frames after a manual label the object is tracked for.
- Tracking range specifies the total range of frames instances are tracked across.
- The Advanced settings lets you to choose between Advanced and Standard tracking models. The Advanced model provides higher accuracy, but takes longer to run.
-
Click Run tracking to track the instance.
Tracking range
The range that quick object tracking runs for can be adjusted in the Object tracking section of the editor settings.
The default tracking range is set to 30 frames.
Object tracking example
Lisa, an annotator, wants to track a blue car on all frames between frame 10
and frame 40
in a video.
- She draws a bounding box around an instance of a blue car on frames 10 and 40.
- She sets the Tracking range to [10,40] and the Tracking annotation interval to
30
. - She clicks Run tracking to label the object from frame
10
to frame40
.
Updated 29 days ago