A deep dive into every component of the YOLO V1 object detector - from downloading and preparing the Pascal VOC data, through network architecture and loss formulation, all the way to training, evaluation, and real-time inference. This repository is designed to give you a clear, end-to-end understanding of how YOLO V1 works under the hood in PyTorch.
YOLOv1-PyTorch/
├── YOLO V1/ # directory containing both notebooks
│ ├── YOLO-V1-Explanation.ipynb # highly comprehensive deep-dive notebook
│ │ ├── Pascal VOC download & preprocessing
│ │ ├── Detailed model architecture breakdown
│ │ ├── Loss function derivation & implementation
│ │ ├── Training loop with logging & checkpoints
│ │ └── Inference examples with visualization
│ └── YOLO-V1-Pure-Code.ipynb # end-to-end pipeline: pure code only
│ ├── Data loading
│ ├── Model definition
│ ├── Loss & optimization
│ ├── Training & evaluation
│ └── Inference with bounding-box visualization
├── sheep.png # sample inference result on a sheep image
├── biker.png # sample inference result on a bicycle image
├── LICENSE # MIT License text
└── README.md # this document
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YOLO-V1-Explanation.ipynb
A comprehensive, annotated walkthrough. Explains why each component exists, how it’s implemented in PyTorch, and how data flows through the network. -
YOLO-V1-Pure-Code.ipynb
The identical implementation stripped of all commentary. Ideal for quick experiments, benchmarking, or integration into other projects.
Below are two example outputs produced by the YOLO V1 pipeline:
- Python 3.7+
- pip
- (Optional) CUDA-enabled GPU for accelerated training and inference
Install the required packages:
pip install torch torchvision opendatasets numpy matplotlib pillow tqdm- Clone the repository
git clone https://github.com/franciszekparma/YOLOv1-PyTorch.git
cd YOLOv1-PyTorch- Launch Jupyter Lab or Notebook
jupyter lab # or: jupyter notebook- Open and run the notebooks • YOLO-V1-Explanation.ipynb for the full, annotated deep dive. • YOLO-V1-Pure-Code.ipynb for a no-frills, code-only run.
Contributions are welcome. Please open an issue or submit a pull request for:
• Bug fixes
• Performance optimizations
• Support for additional datasets
• Documentation improvements
• “You Only Look Once” (YOLO V1) by Joseph Redmon et al.
• Aladdin Persson for providing Pascal VOC dataset via the opendatasets library.
• Inspiration and reference code from Aladdin Persson’s PyTorch tutorials.
• Tushar Kumar (ExplainingAI) for his theory-focused YOLO V1 tutorial.
This project is licensed under the MIT License.
© franciszekparma

