---
license: apache-2.0
task_categories:
  - image-segmentation
  - object-detection
  - robotics
language:
  - en
tags:
  - robotics
  - navigation
  - frontiers
  - autonomous-systems
  - field-robotics
  - vision-foundation-models
  - outdoor-navigation
  - traversability
  - exploration
pretty_name: WildOS Frontiers Dataset
size_categories:
  - n<1K
configs:
  - config_name: default
    data_files:
      - split: train
        path: "**"
---

# WildOS Frontiers Dataset

<div align="center">
  <img src="https://leggedrobotics.github.io/wildos/static/images/Teaser-V.svg" alt="WildOS Teaser" width="800"/>
</div>

## Dataset Description

This dataset provides **visual frontier annotations** for outdoor long-range navigation, created for [WildOS: Open-Vocabulary Object Search in the Wild](https://leggedrobotics.github.io/wildos/). The annotations are built on top of images from the [GrandTour Dataset](https://huggingface.co/datasets/leggedrobotics/grand_tour_dataset).

**Visual Frontiers** denote regions in the image that correspond to candidate locations for further exploration — such as the end of a trail, an opening
between trees, or a road turning at a curve. This dataset enables training of models to predict visual frontiers from RGB images, extending navigation reasoning beyond the geometric depth horizon.

## Dataset Structure

```
wildos/
├── annotations/           # Frontier annotations (362 JSON files)
│   └── annotation_00000.json ... annotation_00389.json
├── RGB_frames/            # Raw RGB frames (390 images + metadata)
│   ├── metadata.json      # Maps to original GrandTour images
│   └── rgb_00000.png ... rgb_00389.png
├── RGB_rectified/         # Rectified RGB images (390 images)
│   └── rect_00000.png ... rect_00389.png
└── SAM_boundaries/        # SAM-2 boundary masks (390 images)
    └── bound_00000.png ... bound_00389.png
```

### File Descriptions

| Folder | Description | Count |
|--------|-------------|-------|
| `annotations/` | JSON files containing frontier bounding box annotations | 362 |
| `RGB_frames/` | Original RGB frames from GrandTour dataset | 390 + 1 metadata |
| `RGB_rectified/` | Rectified (undistorted) RGB images | 390 |
| `SAM_boundaries/` | Binary masks from SAM-2 boundary detection | 390 |

> **Note:** Some images do not have corresponding annotations (362 out of 390 images are annotated). Images without annotations were excluded during quality control. The `SAM_boundaries/` folder contains SAM-2 boundary masks used in an ablation study, where frontiers were defined as the SAM boundary segments within human-annotated bounding boxes.

## Annotation Format

Each annotation file contains a list of frontier detections with the following structure:

```json
[
  {
    "label": "frontier",
    "start": [1326.0, 618.0],
    "end": [1352.0, 636.0]
  }
]
```

| Field | Description |
|-------|-------------|
| `label` | Frontier label (currently `"frontier"` for all annotations) |
| `start` | Top-left corner `[x, y]` of the bounding box |
| `end` | Bottom-right corner `[x, y]` of the bounding box |

> **Note:** The `label` field exists because we initially experimented with labeling frontiers of varying strengths. In the final dataset, all annotations use the single label `"frontier"`.

## Example Annotations

<div align="center">
<table>
<tr>
<td><img src="https://leggedrobotics.github.io/wildos/static/images/label_examples/rect_00001.png" width="400"/></td>
<td><img src="https://leggedrobotics.github.io/wildos/static/images/label_examples/rect_00024.png" width="400"/></td>
</tr>
<tr>
<td><img src="https://leggedrobotics.github.io/wildos/static/images/label_examples/rect_00037.png" width="400"/></td>
<td><img src="https://leggedrobotics.github.io/wildos/static/images/label_examples/rect_00086.png" width="400"/></td>
</tr>
<tr>
<td><img src="https://leggedrobotics.github.io/wildos/static/images/label_examples/rect_00191.png" width="400"/></td>
<td><img src="https://leggedrobotics.github.io/wildos/static/images/label_examples/rect_00264.png" width="400"/></td>
</tr>
</table>
</div>

*Red regions indicate visual frontiers — candidate locations for further exploration.* More examples can be viewed [here](https://leggedrobotics.github.io/wildos/#frontier-annotations).

## Usage

### Loading Individual Files

```python
import json
from PIL import Image

# Load an annotation
with open("wildos/annotations/annotation_00000.json", "r") as f:
    annotations = json.load(f)

# Load corresponding image
image = Image.open("wildos/RGB_rectified/rect_00000.png")

print(f"Image size: {image.size}")
print(f"Number of frontiers: {len(annotations)}")
```

### Visualizing Annotations

Visualize frontier annotations on images:

```python
import os
import json
import cv2
import numpy as np

def visualize_frontiers(image_path, annotation_path, output_path=None):
    """Draw frontier annotations on an image."""
    # Load image
    img = cv2.imread(image_path)
    
    # Load annotations
    with open(annotation_path, "r") as f:
        annotations = json.load(f)
    
    # Draw each frontier
    for ann in annotations:
        x1, y1 = int(ann["start"][0]), int(ann["start"][1])
        x2, y2 = int(ann["end"][0]), int(ann["end"][1])
        color = (0, 0, 255)  # Red in BGR
        
        # Draw semi-transparent rectangle
        overlay = img.copy()
        cv2.rectangle(overlay, (x1, y1), (x2, y2), color, -1)
        cv2.addWeighted(overlay, 0.35, img, 0.65, 0, img)
        cv2.rectangle(img, (x1, y1), (x2, y2), color, 2)
    
    if output_path:
        cv2.imwrite(output_path, img)
    
    return img

# Example usage
visualize_frontiers(
    "wildos/RGB_rectified/rect_00000.png",
    "wildos/annotations/annotation_00000.json",
    "output_visualization.png"
)
```

### Metadata Mapping

The `metadata.json` file in `RGB_frames/` maps each image index to its source path in the GrandTour dataset:

```python
import json

with open("wildos/RGB_frames/metadata.json", "r") as f:
    metadata = json.load(f)

# Find original GrandTour image for a specific frame index
original_path = metadata["0"]  # e.g., "release_2024-11-03-07-57-34/hdr_front/hdr_front_01342.png"
print(f"Original GrandTour path: {original_path}")
```

## Related Resources

- **Project Page**: [WildOS: Open-Vocabulary Object Search in the Wild](https://leggedrobotics.github.io/wildos/)
- **Source Dataset**: [GrandTour Dataset](https://huggingface.co/datasets/leggedrobotics/grand_tour_dataset)

## Citation

If you use this dataset in your research, please cite:

```bibtex
@misc{shah2026wildosopenvocabularyobjectsearch,
        title={WildOS: Open-Vocabulary Object Search in the Wild}, 
        author={Hardik Shah and Erica Tevere and Deegan Atha and Marcel Kaufmann and Shehryar Khattak and Manthan Patel and Marco Hutter and Jonas Frey and Patrick Spieler},
        year={2026},
        eprint={2602.19308},
        archivePrefix={arXiv},
        primaryClass={cs.RO},
        url={https://arxiv.org/abs/2602.19308}, 
}
```

## License

This dataset is released under the [Apache 2.0 License](https://www.apache.org/licenses/LICENSE-2.0).