M3D-Stereo/M3D-Stereo

---
license: lgpl-3.0
---

# M3D-Stereo: A Multiple-Medium and Multiple-Degradation Dataset for Stereo Image Restoration

M3D-Stereo is a real-captured stereo image restoration dataset covering four degradation scenarios: underwater scatter (UWST), underwater low-light (UWLL), haze/fog scatter (HZST), and coupled haze low-light (HZLL). Each scenario provides 16 scenes at six progressive degradation levels (D1–D6) with pixel-aligned clear ground truths, captured by two calibrated ZED stereo cameras (Camera 1 / Camera 2, denoted `c1` / `c2`).

---

## File Structure

```
M3D-Stereo/
├── UWST/ # Underwater scatter
│ ├── scene1/
│ │ ├── d1/
│ │ │ ├── c1/ image_left/ image_right/
│ │ │ └── c2/ image_left/ image_right/
│ │ ├── d2/ ... d5/
│ │ └── d6/
│ │ ├── c1/ image_left/ image_right/
│ │ └── c2/ image_left/ image_right/
│ ├── scene2/ ... scene15/
│ └── scene16/
│
├── UWLL/ # Underwater low-light
│ ├── scene1/ ... scene16/ (same structure as UWST)
│
├── HZST/ # Haze/fog scatter
│ ├── scene1/ ... scene16/ (same structure as UWST)
│
├── HZLL/ # Coupled haze + low-light
│ ├── scene1/ ... scene16/ (same structure as UWST)
│
├── UW_GT/ # Ground truths for UWST & UWLL
│ ├── scene1/
│ │ ├── c1/ image_left/ image_right/
│ │ └── c2/ image_left/ image_right/
│ ├── scene2/ ... scene15/
│ └── scene16/
│
├── HZ_GT/ # Ground truths for HZST & HZLL
│ ├── scene1/
│ │ ├── c1/ image_left/ image_right/
│ │ └── c2/ image_left/ image_right/
│ ├── scene2/ ... scene15/
│ └── scene16/
│
└── Camera_Parameters/
├── HZ/
│ ├── c1/ HZ_c1.txt
│ └── c2/ HZ_c2.txt
└── UW/
├── c1/ UW_c1.txt
└── c2/ UW_c2.txt
```

- `c1` / `c2`: two stereo camera systems, independently calibrated for air and underwater environments.
- `image_left` / `image_right`: rectified stereo image pairs at 1920×1080.
- GT images are captured under clean-medium and full illumination conditions with identical scene layout, ensuring pixel-wise alignment with degraded inputs across all levels.

---

## Dataset Statistics

| Subset | Scenes | Degradation | Levels | GT Source |
|--------|--------|-------------|--------|-----------|
| UWST | scene1–scene16 | Underwater scatter (milk concentration) | D1–D6 | UW_GT |
| UWLL | scene1–scene16 | Underwater low-light (PWM dimming) | D1–D6 | UW_GT |
| HZST | scene1–scene16 | Haze/fog scatter (fog machine duration) | D1–D6 | HZ_GT |
| HZLL | scene1–scene16 | Coupled haze + low-light | D1–D6 | HZ_GT |

Each scene contains stereo pairs from two cameras (`c1`, `c2`) across six degradation levels, yielding a total of 16 × 6 × 2 = 192 stereo-pair groups per degradation subset.

---

## Camera Parameters

Two ZED Mini stereo cameras are used. The **UW** camera pair operates in an underwater housing; the **HZ** camera pair operates in air. Each camera is independently calibrated using a 7×7 symmetric circle grid (15 mm spacing) via OpenCV stereo calibration. Full calibration files (intrinsics, distortion, rotation, translation, and rectification maps) are provided under `Camera_Parameters/`.

| Camera | Focal Length (px) | Principal Point (px) | Baseline (mm) | Reproj. Error (px) |
|--------|-------------------|----------------------|----------------|---------------------|
| UW c1 left | 1869.37, 1875.38 | 996.62, 594.86 | 62.98 | 0.046 |
| UW c1 right | 1871.29, 1876.57 | 987.59, 558.72 | | 0.043 |
| UW c2 left | 1874.22, 1888.86 | 971.47, 637.44 | 62.81 | 0.047 |
| UW c2 right | 1870.74, 1885.61 | 998.86, 622.44 | | 0.054 |
| HZ c1 left | 1401.27, 1400.39 | 991.60, 520.24 | 62.79 | 0.034 |
| HZ c1 right | 1401.12, 1400.67 | 986.85, 490.90 | | 0.034 |
| HZ c2 left | 1401.81, 1401.30 | 971.40, 529.15 | 62.81 | 0.039 |
| HZ c2 right | 1399.04, 1398.84 | 993.80, 511.61 | | 0.038 |

---

## License

This dataset is released under the [LGPLv3 License](https://www.gnu.org/licenses/lgpl-3.0.html).

---

## Citation

```bibtex
@inproceedings{yang2026m3dstereo,
title = {M3D-Stereo: A Multiple-Medium and Multiple-Degradation Dataset for Stereo Image Restoration},
author = {Deqing Yang and Yingying Liu and Qicong Wang and Zhi Zeng and Dajiang Lu and Yibin Tian},
year = {2026}
}
```