> For the complete documentation index, see [llms.txt](https://docs.imerit.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.imerit.net/3d-multi-sensor-fusion/labeling/3d-multi-sensor-fusion-labeling-editor/key-features/velocity-graph.md).

# Velocity Graph

The Velocity Graph displays how an object's speed changes across a sequence, enabling users to detect annotation errors and physically implausible motion at a glance.

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## Use Cases

**Autonomous Driving - Highway Vehicle Tracking**\
When annotating fast-moving vehicles on a highway sequence, sudden spikes in the velocity graph immediately reveal frames where a cuboid was accidentally misplaced or where keyframe interpolation has overshot the realistic path - without needing to scrub through every frame manually.

**Robotics - Moving Equipment**\
In warehouse or manipulation datasets, the velocity graph helps reviewers confirm that robotic arms or moving equipment follow physically consistent motion paths, catching abrupt jumps that indicate incorrect keyframe placement across a sequence.

**Agri-Tech - Monitoring Machinery Across Fields**\
When tracking tractors or drones across long sequences, the velocity graph surfaces frames where the object's speed deviates unexpectedly, helping annotators distinguish genuine motion changes from annotation drift or copy-paste errors.

**Aviation - Aircraft Annotation Quality Review**\
When annotating aircraft sequences, the velocity graph gives auditors a rapid way to identify spikes in an object's speed profile and determine whether a sequence requires an additional round of internal QA - without scrubbing through every frame individually. In one instance, a delivery team reviewing flagged spikes discovered that the root cause was not an annotation error but LiDAR sensor jitter on specific frames - a finding that would have been difficult to isolate without the velocity graph surfacing the affected frames directly.

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## Benefits

* **For Annotators:** Provides an immediate, at-a-glance view of an object's speed profile across the sequence without manually scrubbing through frames, reducing time per object during tracking and interpolation tasks.
* **For Customers (AI/ML & Perception Engineering):** Enables direct visual validation of object motion data against expected real-world speed profiles. Higher confidence in motion data quality translates directly into more reliable velocity estimation and trajectory prediction model training.
* **Cost Efficiency:** Surface-level motion anomalies that previously required frame-by-frame scrubbing to detect can now be identified in seconds from the graph, reducing QA time and the cost of late-stage corrections on motion-critical datasets.

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## Steps to Use

{% hint style="info" %}
The Velocity Graph requires **ego pose data** and **timestamped frames** to compute velocity accurately. If either is absent, the Velocity Graph option will not appear in the right-click menu.

{% endhint %}

{% stepper %}
{% step %}
Create a cuboid annotation on the frame where the object appears most well defined.
{% endstep %}

{% step %}
Track the object across the sequence using keyframe interpolation, repositioning the cuboid every 5–7 frames as needed.
{% endstep %}

{% step %}
Once tracking is complete, select the cuboid and right-click to open the context menu.
{% endstep %}

{% step %}
Click **Velocity Graph,** a graph window appears 

* The graph plots velocity (m/s) on the Y-axis against absolute frame numbers on the X-axis. Forward velocity is displayed by default.
* Hover over any point on the graph to reveal a crosshair and tooltip showing the exact frame number and velocity value. For occluded frame ranges where the cuboid was deleted between keyframes, the graph renders a gap in the line and the tooltip displays "Frame N · NA" with no velocity value.
* To inspect dense sequences, scroll the mouse wheel over the graph to zoom. Click and drag to pan across the frame range after zooming in.
* To return to the full sequence view, click the reset button to restore the default zoom and pan state. The zoom and pan state also resets automatically when a different cuboid is selected.
* To explore velocity on a specific axis or plane, use the dropdown on the graph to select from Vx, Vy, Vz, or a combination. The Y-axis label updates to reflect the selection (e.g., "Velocity - Vxy (m/s)"). The name of the selected object appears in the graph heading.
  {% endstep %}
  {% endstepper %}