README.md

---
dataset_info:
  features:
  - name: image_id
    dtype: int64
  - name: image
    dtype: image
  - name: width
    dtype: int32
  - name: height
    dtype: int32
  - name: objects
    struct:
    - name: id
      list: int64
    - name: area
      list: int64
    - name: bbox
      list:
        list: float32
        length: 4
    - name: category
      list: int64
  splits:
  - name: train
    num_bytes: 31928785
    num_examples: 500
  - name: validation
    num_bytes: 7004874
    num_examples: 100
  - name: test
    num_bytes: 3954856
    num_examples: 50
  download_size: 42902433
  dataset_size: 42888515
configs:
- config_name: default
  data_files:
  - split: train
    path: data/train-*
  - split: validation
    path: data/validation-*
  - split: test
    path: data/test-*
task_categories:
- object-detection
tags:
- yolo
- ultralytics
- yolov8
- yolov11
- detection
- synthetic
license: apache-2.0
size_categories:
- n<1K
---

# 🎯 YOLO Object Detection Dataset

A synthetic object detection dataset with **5 classes**, ready for training YOLOv8/v11 models.

## 📊 Dataset Summary

| | Train | Validation | Test |
|---|---|---|---|
| **Images** | 500 | 100 | 50 |
| **Hard negatives** | 75 (15%) | 15 (15%) | 7 (15%) |
| **Image size** | 640×640 | 640×640 | 640×640 |

## 🏷️ Classes

| ID | Class | Visual |
|---|---|---|
| 0 | `car` | Red car-shaped rectangles with windows & wheels |
| 1 | `person` | Blue stick figures with body parts |
| 2 | `dog` | Brown dog shapes with legs & tail |
| 3 | `cat` | Orange cat shapes with ears & eyes |
| 4 | `bicycle` | Green bicycle with wheels & frame |

## 📁 Two Formats Available

### 1. HF Datasets (Parquet) — Browse & Load Programmatically
```python
from datasets import load_dataset
ds = load_dataset("dharshanzeb/yolo-detection-dataset")
print(ds["train"][0])
# {'image_id': 0, 'image': <PIL>, 'width': 640, 'height': 640,
#  'objects': {'id': [...], 'area': [...], 'bbox': [[x,y,w,h], ...], 'category': [...]}}
```

### 2. YOLO Format (Zips) — Direct Training with Ultralytics
Download from [`yolo_format/`](yolo_format/):
- `train.zip` — 500 images + labels
- `val.zip` — 100 images + labels
- `test.zip` — 50 images + labels
- `data.yaml` — YOLO config file

**Annotation format** (YOLO txt — one `.txt` per image):
```
<class_id> <x_center> <y_center> <width> <height>
# All values normalized 0-1
0 0.492188 0.403125 0.212500 0.315625
1 0.720312 0.150000 0.080000 0.120000
```

## 🚀 Train YOLOv8 (Quick Start)

### Google Colab / Local
```python
# Install
!pip install ultralytics

from ultralytics import YOLO

# Download and prepare dataset
from huggingface_hub import hf_hub_download
import zipfile, os

for split in ["train", "val", "test"]:
    zip_path = hf_hub_download(
        repo_id="dharshanzeb/yolo-detection-dataset",
        filename=f"yolo_format/{split}.zip",
        repo_type="dataset"
    )
    with zipfile.ZipFile(zip_path) as z:
        z.extractall("./dataset/")

# Download data.yaml
yaml_path = hf_hub_download(
    repo_id="dharshanzeb/yolo-detection-dataset",
    filename="yolo_format/data.yaml",
    repo_type="dataset"
)

# Update path in data.yaml to point to extracted folder
import yaml
with open(yaml_path) as f:
    cfg = yaml.safe_load(f)
cfg["path"] = os.path.abspath("./dataset")
with open("data.yaml", "w") as f:
    yaml.dump(cfg, f)

# Train!
model = YOLO("yolov8n.pt")  # nano model for fast training
results = model.train(
    data="data.yaml",
    epochs=50,
    imgsz=640,
    batch=16,
    device=0,          # GPU
    pretrained=True,
    mosaic=1.0,
    mixup=0.1,
    project="runs/train",
    name="yolo_custom",
)

# Evaluate
metrics = model.val()
print(f"mAP50: {metrics.box.map50:.3f}")
print(f"mAP50-95: {metrics.box.map:.3f}")

# Predict
results = model.predict("test_image.jpg", conf=0.25)
results[0].show()
```

### Convert HF Dataset → YOLO Format (Alternative)
```python
from datasets import load_dataset
from pathlib import Path

ds = load_dataset("dharshanzeb/yolo-detection-dataset")

for split_name, split_key in [("train","train"), ("val","validation"), ("test","test")]:
    img_dir = Path(f"dataset/images/{split_name}")
    lbl_dir = Path(f"dataset/labels/{split_name}")
    img_dir.mkdir(parents=True, exist_ok=True)
    lbl_dir.mkdir(parents=True, exist_ok=True)

    for idx, row in enumerate(ds[split_key]):
        stem = f"img_{idx:05d}"
        row["image"].save(img_dir / f"{stem}.jpg")
        
        lines = []
        W, H = row["width"], row["height"]
        for bbox, cat in zip(row["objects"]["bbox"], row["objects"]["category"]):
            x, y, w, h = bbox
            cx, cy = (x + w/2) / W, (y + h/2) / H
            lines.append(f"{cat} {cx:.6f} {cy:.6f} {w/W:.6f} {h/H:.6f}")
        
        with open(lbl_dir / f"{stem}.txt", "w") as f:
            f.write("\n".join(lines))
```

## 📋 Dataset Details

- **Hard negatives**: 15% of images contain no objects (empty label files). This is critical for reducing false positives during training — a technique from the synthetic-to-real YOLO paper (arXiv:2509.15045).
- **Backgrounds**: Gradient and textured backgrounds with noise for visual diversity.
- **Augmentation-ready**: Designed for use with YOLO's built-in Mosaic + Mixup augmentations.
- **Bounding boxes**: COCO format `[x_min, y_min, width, height]` in the HF dataset; YOLO normalized format in the zip files.

## 📜 License

Apache 2.0