---
license: apache-2.0
library_name: timm
tags:
- bees
- beekeeping
- image-classification
- efficientnet
pipeline_tag: image-classification
---

# Apiarist Queen-vs-Worker Bee Classifier

Binary image classifier (EfficientNet-B0, ~5M params) trained to
distinguish queen bees from worker bees on cropped bee images.

Built as part of [Apiarist](https://huggingface.co/spaces/build-small-hackathon/Apiarist),
an offline AI hive inspector for backyard beekeepers, made for the
[Build Small Hackathon](https://huggingface.co/build-small-hackathon).

## Why a dedicated classifier?

Multi-class YOLO detectors fight two problems at once (localize + classify)
and queens lose because they're rare and visually subtle. A focused
binary classifier on cropped bee images is the right architecture:
small, fast, trained specifically for one decision.

## Training

- Backbone: `efficientnet_b0` (ImageNet pretrained)
- Training data: bee crops extracted from labelled bounding boxes in two
  Roboflow datasets (Matt Nudi honey bees + Hendricks Ricky bee-project)
- 1,146 queen crops + 29,825 worker crops, balanced via weighted sampling
- Heavy augmentation: rotations, flips, color jitter
- 90/10 train/val split, weighted random sampling for class balance
- AdamW + cosine schedule, mixed precision on a single T4 GPU
- Trained on [Modal](https://modal.com)

## Validation metrics

- Accuracy: 0.997
- Precision (queen): 0.991
- Recall (queen): 0.934
- **F1: 0.962**

## Recommended use

Pair with a bee detector (e.g. YOLOv8). Run the detector first, then
classify each cropped bee through this model. Threshold queen
probability at 0.85 for high-precision flagging.

```python
import torch, timm
from torchvision import transforms

ckpt = torch.load("queen_classifier.pt", map_location="cpu")
model = timm.create_model(ckpt["arch"], pretrained=False, num_classes=2)
model.load_state_dict(ckpt["state_dict"])
model.eval()

tf = transforms.Compose([
    transforms.Resize((224, 224)),
    transforms.ToTensor(),
    transforms.Normalize([0.485,0.456,0.406], [0.229,0.224,0.225]),
])

with torch.no_grad():
    probs = torch.softmax(model(tf(crop).unsqueeze(0)), dim=1)
queen_idx = ckpt["class_to_idx"]["queen"]
queen_prob = probs[0, queen_idx].item()
```

## Caveats

The training distribution leans toward close-up macro photos of bees on
honeycomb. Generalization to wide-angle inspection photos (with hands /
background visible) is weaker, since YOLO's bee bounding boxes on those
photos are often smaller and less precise than the training crops.

## License

Apache 2.0. Trained on data released under CC BY 4.0.