Auto-annotating camera and LiDAR data with foundation models

Labelling camera and LiDAR data is slow and expensive. How foundation-model pre-labels and camera-LiDAR fusion speed it up without lowering quality.

A LiDAR point cloud of a city street intersection in purple and orange
A LiDAR point cloud of a street intersection.

Annotation is often the most expensive part of a perception project. Every frame from a camera and every sweep from a LiDAR needs labels before a model can learn from it.

Pre-label, then review

The pipeline does not replace annotators. It gives them a first draft: masks from foundation models on the camera image, projected onto the point cloud through the camera-LiDAR calibration. Annotators correct the draft instead of drawing from scratch.

Keeping quality honest

A pre-label that is almost right can be worse than none, because people stop looking closely. Each batch is compared against a sample labelled by hand, and the pre-labels are switched off for any scene type where they fall below the agreed quality.

The result

On the project at Continental, pre-labelling cut labelling costs by 70%.