Automated labeling and why you should care!

If you’ve ever added a new object class to your YOLO or object detection model, you’ve probably faced this scenario:

“We want to detect electric scooters with delivery bags.”

So, you collect a ton of footage from city intersections. You annotate all the scooters with delivery gear, retrain your model, and push it to production.

Then... performance drops on cars, pedestrians, and cyclists.

Why?
Because in your new dataset, you only labeled the new class, and left everything else unlabeled.


🧠 The Pitfall of Partial Labeling

YOLO-style detectors don’t know that the other objects in your image (like cars, pedestrians, bikes). If you don’t label them, they’re treated as background.

Which means:

  • Cars that used to be detected are now ignored

  • Pedestrians are misclassified or missed entirely

  • Your model's mAP for existing classes plummets

This happens silently. And that’s the scary part.


⚠️ Why This Is a Big Deal

Let’s say your model previously supported:

  • 🚗 Cars

  • 🚲 Bicycles

  • 🧍 Pedestrians

Now you add a new class:

  • 🛵 Electric Scooters with Delivery Bags

But the new videos you collected also include all the old classes.

If you don’t relabel those existing classes, your new model thinks they’re background. The model gradually forgets what it used to know. Something we call catastrophic forgetting.


⚡ Enter Automated Labeling

Automated labeling solves this perfectly.

Here’s the idea:

  1. Run your existing YOLO model on the new dataset.

  2. Use it to auto-label known classes like cars, bikes, and pedestrians.

  3. Manually annotate only the new class (e-scooters with delivery bags).

  4. Merge labels → retrain.

Done. Your new dataset now includes all relevant classes, with minimal manual effort.


🛠 Tools to Help You Do This

  • Roboflow – Auto-label known classes from your existing models

  • CVAT + Model-assisted labeling – Load predictions as annotations

  • Supervision (Roboflow/PyTorch) – Auto-annotate video frames in batch

  • SageMaker Ground Truth – Semi-automated annotation with human review


Real-World Use Case

Imagine you're building a smart city AI platform.

You want to track:

  • Delivery scooters (your new class)

  • Bicycles, cars, people (existing classes)

Instead of re-labeling everything from scratch or ignoring old classes in new data, you automate it:

  • Run inference on the new data

  • Use model predictions to fill in cars, bikes, people

  • Focus only on new-class labeling manually

  • Retrain

Result: your model learns to detect scooters without forgetting how to see the rest of the city.


Bonus: Label New Classes with Few-Shot Learning

Even manual labeling of the new class can be expensive—especially if you’re dealing with edge cases or rare categories. That’s where few-shot or one-shot models come in.

Imagine using a vision-language model like CLIP or BLIP to detect "electric scooters with delivery bags" by just describing it in text:

“A person riding a scooter with a delivery bag.”

These models can:

  • Automatically filter relevant frames from large video datasets

  • Generate bounding boxes with natural language prompts

  • Bootstrap labels even for previously unseen object types

This is a powerful way to:

  • Cut down initial annotation time for niche classes

  • Pre-label candidates for human validation

  • Maintain velocity while still onboarding new labels

Tools to Try:

  • Grounding DINO + Segment Anything (SAM) – Open-vocabulary object detection and segmentation

  • CLIP / BLIP – For image-text matching and filtering

  • OWL-ViT – Open-world detection with free-form text queries

Example:

You describe your class as:

“Electric scooter with a delivery box.”

Run it through a Grounding DINO pipeline → get bounding boxes → send for human validation → you're training in a fraction of the time.

🧠 Final Thought

Automated labeling isn’t just about saving time. It’s about protecting your model’s intelligence.

Every time you expand your dataset with new object classes, you're at risk of degrading what the model already knows.

If you’re not re-labeling known classes in new data, you’re not just cutting corners, you’re undermining your model’s foundation.

So next time you scale up your object detector…

Label everything.
Automatically.

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Written by

Siddhi Kiran Bajracharya
Siddhi Kiran Bajracharya

Hi there! I'm a machine learning, python guy. Reach out to me for collaboration and stuff! :D