---
license: apache-2.0
library_name: pytorch
pipeline_tag: image-segmentation
tags:
- image-segmentation
- pytorch
- unet
- fungal-colony
- petri-dish
- morphometry
- magnaporthe
- area-consistency
language:
- en
---

# 🔬 Gray Leaf Spot Segmentation Model

PyTorch U-Net models for **gray leaf spot** (*Magnaporthe* and related fungal) colony segmentation on 90 mm petri-dish images.

**[▶ Try the live demo](https://huggingface.co/spaces/rotsl/grayleafspot-segmentation-demo)** — upload images, run inference, see overlays & growth charts in your browser.

---

## Model Weights

| File | Architecture | Params | Area-Consistency Weight | Description |
|---|---|---|---|---|
| `grayleafspot.pt` | smp.Unet (ResNet-34) | ~24.4 M | — | Main encoder–decoder model |
| `best_area_w_0.1.pt` | SmallUNet | ~250 K | 0.1 | Light area regularisation |
| `best_area_w_0.3.pt` | SmallUNet | ~250 K | 0.3 | Moderate area regularisation |
| `best_area_w_0.5.pt` | SmallUNet | ~250 K | 0.5 | Balanced BCE + area |
| **`best_area_w_0.7.pt`** | **SmallUNet** | **~250 K** | **0.7** | **Strong area consistency (used by demo) ✅ recommended** |

All SmallUNet variants share the same architecture:

```
Input (3 × 256 × 256)
  │
  ├─ enc1: ConvBlock(3 → 16)              ─── skip s1
  ├─ enc2: MaxPool2d → ConvBlock(16 → 32)  ─── skip s2
  ├─ enc3: MaxPool2d → ConvBlock(32 → 64)  ─── skip s3
  ├─ enc4: MaxPool2d → ConvBlock(64 → 128) ─── skip s4
  │
  ├─ bottleneck: MaxPool2d → ConvBlock(128 → 256)
  │
  ├─ up4: Upsample + cat(s4) → ConvBlock(384 → 128)
  ├─ up3: Upsample + cat(s3) → ConvBlock(192 → 64)
  ├─ up2: Upsample + cat(s2) → ConvBlock(96 → 32)
  ├─ up1: Upsample + cat(s1) → ConvBlock(48 → 16)
  │
  └─ head: Conv2d(16 → 1) → Sigmoid
```

Each `ConvBlock` = Conv3×3 (no bias) → ReLU → Conv3×3 (no bias) → ReLU.

| Property | Value |
|---|---|
| **Input** | 256 × 256 RGB |
| **Output** | 1-channel sigmoid probability mask |
| **Training loss** | BCE + area-consistency loss |
| **CPU compatible** | ✅ Pure PyTorch — no custom CUDA kernels |

---

## Quick Start

### Download & Inference (SmallUNet)

```python
import torch
from huggingface_hub import hf_hub_download

# Download weights
path = hf_hub_download("rotsl/grayleafspot-segmentation", "best_area_w_0.7.pt")

# Load checkpoint
ckpt = torch.load(path, map_location="cpu", weights_only=False)

# Build model (SmallUNet architecture — see demo repo for full class definition)
# https://huggingface.co/rotsl/grayleafspot-segmentation-demo/blob/main/app.py
from model import SmallUNet  # or copy the class from the demo app.py

model = SmallUNet(in_channels=3, out_channels=1, base_channels=16)
model.load_state_dict(ckpt["model_state_dict"])
model.eval()

# Run inference on a 256×256 RGB tensor
import numpy as np
from PIL import Image

img = Image.open("petri_dish.jpg").convert("RGB").resize((256, 256))
x = torch.from_numpy(np.array(img).transpose(2, 0, 1)).float() / 255.0
x = x.unsqueeze(0)

with torch.no_grad():
    prob = model(x)[0, 0].numpy()

mask = (prob > 0.5).astype(np.uint8) * 255
Image.fromarray(mask).save("colony_mask.png")
```

### Download & Inference (Main U-Net)

```python
import torch

path = hf_hub_download("rotsl/grayleafspot-segmentation", "grayleafspot.pt")
model = torch.load(path, map_location="cpu", weights_only=False)
model.eval()
```

---

## Training & Inference Pipeline

### Environment Setup (Apple Silicon recommended)

```bash
python3.10 -m venv trainenv
source trainenv/bin/activate
pip install --upgrade pip
pip install -r requirements.txt
```

### Dataset Preparation

Place raw images in `raw/` and corresponding masks in `masks/` (matching filenames). Expand the dataset with augmentations:

```bash
python src/build_augmented_dataset.py --copies-per-image 4 --clean
```

### Training

Standard U-Net training:

```bash
python src/train.py \
    --image-dir augmented_dataset/raw \
    --mask-dir augmented_dataset/masks \
    --epochs 40 --batch-size 4 --lr 1e-4 \
    --image-size 256 --freeze-encoder-epochs 5
```

Area-consistency U-Net (LabelMe JSON polygons):

```bash
./trainenv/bin/python src/area_consistency/train_area.py
```

### Inference (CLI)

Single image:

```bash
python src/predict.py --input raw/your_image.jpg --weights models/best_finetuned.pt --output-dir predictions
```

Folder:

```bash
python src/predict.py --input raw --weights models/best_finetuned.pt --output-dir predictions
```

### Best Practices

- Keep trusted human-labelled masks unchanged.
- Use augmentations and area-consistency loss for improved generalisation.
- Inspect overlay outputs to verify mask quality.
- On Apple Silicon, MPS acceleration is used automatically if available.

---

## Demo Spaces

### ✅ Recommended: [`rotsl/grayleafspot-segmentation-demo`](https://huggingface.co/spaces/rotsl/grayleafspot-segmentation-demo)

Uses **`best_area_w_0.7.pt`** (SmallUNet with area-consistency loss). More accurate segmentation with better boundary adherence thanks to the area-consistency regularisation.

Features: dish detection → colony segmentation → crack & hyphae analysis → 16 morphometric measurements → time-series growth charts → CSV/JSON export.

Source code: [`rotsl/grayleafspot-segmentation-demo`](https://huggingface.co/rotsl/grayleafspot-segmentation-demo) (model repo)

### Legacy: [`rotsl/fungal-colony-input`](https://huggingface.co/spaces/rotsl/fungal-colony-input)

Uses **`grayleafspot.pt`** (smp.Unet with ResNet-34 encoder). This is the earlier, larger model trained with standard BCE loss only — it is less accurate than the area-consistency variant above, particularly for colony boundary delineation and area estimation. Kept available for reference and backward compatibility.

---

## Citation

```bibtex
@misc{rohan_r_2026,
  author       = {rohan r},
  title        = {grayleafspot-segmentation (Revision 0e85f71)},
  year         = 2026,
  url          = {https://huggingface.co/rotsl/grayleafspot-segmentation},
  doi          = {10.57967/hf/8416},
  publisher    = {Hugging Face}
}
```

## License

Apache License 2.0 — see [LICENSE](LICENSE) for details.