# Cloud Removal Training với SEN12MS-CR Dataset

Hướng dẫn train Deep Learning model để khử mây từ ảnh Sentinel-2 sử dụng dataset SEN12MS-CR.

## 📂 Cấu trúc dữ liệu

```
winter_dataset/
├── ROIs2017_winter_s1/          # Sentinel-1 SAR data (VV, VH)
│   ├── s1_8/
│   ├── s1_9/
│   └── ...
├── ROIs2017_winter_s2/          # Sentinel-2 CLEAN (ground truth)
│   ├── s2_8/
│   ├── s2_9/
│   └── ...
├── ROIs2017_winter_s2_cloudy/   # Sentinel-2 CLOUDY (input)
│   ├── s2_cloudy_8/
│   ├── s2_cloudy_9/
│   └── ...
└── sen12ms_cr_dataLoader.py     # Data loader
```

## 🚀 Quick Start

### 1. Training Model

```bash
# Activate environment
conda activate env_01

# Train cloud removal model
python train_cloud_removal.py
```

**Hyperparameters mặc định:**
- Use S1: `True` (sử dụng radar data)
- Batch size: `8`
- Epochs: `50`
- Learning rate: `1e-4`
- Model: U-Net
- Loss: MAE (L1 Loss)

### 2. Test Training (Quick)

```bash
# Test với 5 epochs
python test_cloud_training.py
```

### 3. Sử dụng Model đã train

```python
from cloud_removal import process_cloud_removal

# Load Sentinel-2 data
s2_data = load(...)  # Your S2 data with SCL band

# Apply deep learning cloud removal
cleaned_data, metadata = process_cloud_removal(
    s2_data=s2_data,
    method="deep",  # Use deep learning method
    verbose=True
)
```

## 🎯 Model Architecture

**U-Net** với cấu trúc:
- **Input:** S2 cloudy (4 bands: B02, B03, B04, B08) + S1 (2 bands: VV, VH) = 6 channels
- **Output:** S2 clean (4 bands) = 4 channels
- **Features:** [64, 128, 256, 512]
- **Skip connections:** Encoder → Decoder
- **Activation:** ReLU + BatchNorm

## 📊 Dataset Info

**SEN12MS-CR** (Sentinel-12 Multi-Seasonal Cloud Removal):
- **Scenes:** ~2000+ patches
- **Size:** 256x256 pixels
- **Bands:**
  - S1: VV, VH (2 channels)
  - S2: 13 bands (chọn B02, B03, B04, B08 cho training)
- **Seasons:** Spring, Summer, Fall, Winter
- **Source:** [https://github.com/PatrickTUM/SEN12MS-CR](https://github.com/PatrickTUM/SEN12MS-CR)

## 🔧 Customization

### Thay đổi hyperparameters

```python
from train_cloud_removal import train_cloud_removal_model

model, train_losses, val_losses = train_cloud_removal_model(
    data_dir="winter_dataset",
    use_s1=True,           # Có dùng S1 không
    batch_size=16,         # Tăng nếu có GPU mạnh
    num_epochs=100,        # Số epochs
    learning_rate=5e-5,    # Learning rate
    device="cuda",         # "cuda" hoặc "cpu"
    save_dir="model_train" # Thư mục lưu model
)
```

### Chỉ dùng S2 (không dùng S1)

```python
model, train_losses, val_losses = train_cloud_removal_model(
    use_s1=False,  # Không dùng radar data
    # ... other params
)
```

### Thay đổi S2 bands

Sửa trong `train_cloud_removal.py`:

```python
# Thay vì RGB + NIR
s2_bands = [S2Bands.B02, S2Bands.B03, S2Bands.B04, S2Bands.B08]

# Có thể dùng tất cả bands
s2_bands = S2Bands.ALL
```

## 📈 Monitoring Training

Model tự động lưu:
- **Best model:** `model_train/cloud_removal_unet_best.pth`
- **Training curves:** `model_train/training_curves.png`
- **Visualizations:** `model_train/cloud_removal_epoch_*.png` (mỗi 10 epochs)

## 🌐 Tích hợp vào API

Model đã được tích hợp vào `cloud_removal.py`:

```python
# API endpoint
GET /api/cloud-removal/methods

# Response
{
  "methods": {
    "deep": "Deep Learning U-Net inpainting (best quality, requires model)"
  }
}
```

Sử dụng trong prediction:

```json
{
  "model_filename": "model_odc.joblib",
  "cloud_removal_method": "deep",
  "..."
}
```

## 📝 Notes

### GPU Requirements
- **Recommended:** NVIDIA GPU với >= 6GB VRAM
- **Minimum:** CPU (chậm hơn ~10x)

### Training Time
- **GPU (RTX 3060):** ~2-3 hours cho 50 epochs
- **CPU:** ~20-30 hours cho 50 epochs

### Data Download
Nếu chưa có dữ liệu, download từ:
```bash
# Download SEN12MS-CR dataset
wget https://mediatum.ub.tum.de/download/1554803/1554803.zip
unzip 1554803.zip -d winter_dataset/
```

## 🐛 Troubleshooting

### 1. CUDA out of memory
```python
# Giảm batch size
batch_size=4  # hoặc 2
```

### 2. Import error
```bash
# Kiểm tra dependencies
pip install torch torchvision tqdm matplotlib
```

### 3. Model không load được
```python
# Kiểm tra path
model_path = "model_train/cloud_removal_unet_best.pth"
assert Path(model_path).exists()
```

## 📚 References

- **Paper:** SEN12MS-CR: A Dataset for Cloud Removal in Sentinel-2 Imagery
- **GitHub:** https://github.com/PatrickTUM/SEN12MS-CR
- **U-Net:** Ronneberger et al., "U-Net: Convolutional Networks for Biomedical Image Segmentation"

## ✅ Checklist

- [x] Data loader cho SEN12MS-CR
- [x] U-Net architecture
- [x] Training script
- [x] Visualization
- [x] Model saving/loading
- [x] Tích hợp vào cloud_removal.py
- [x] API integration
- [x] Test script
- [x] Documentation

## 🎓 Next Steps

1. **Train model:** `python train_cloud_removal.py`
2. **Evaluate:** Xem visualizations trong `model_train/`
3. **Test inference:** Dùng `test_cloud_removal.py`
4. **Deploy:** Model tự động được dùng khi chọn `cloud_removal_method="deep"`

---

**Tác giả:** AI Assistant  
**Ngày tạo:** 2026-01-21  
**Version:** 1.0
