---
license: bsd-3-clause
library_name: libreyolo
pipeline_tag: object-detection
datasets:
  - detection-datasets/coco
tags:
  - object-detection
  - ssd
  - torchvision
  - libreyolo
---

# LibreSSD300

SSD300 with a VGG16 backbone, repackaged for LibreYOLO as an inference-only
historic model. Input is fixed at 300 x 300.

```python
from libreyolo import LibreYOLO

model = LibreYOLO("LibreSSD300.pt")
results = model.predict("image.jpg")
```

## Source

Derived from [pytorch/vision](https://github.com/pytorch/vision) at commit
[`336d36e8db990a905498c73933e35231876e28bc`](https://github.com/pytorch/vision/commit/336d36e8db990a905498c73933e35231876e28bc).
Copyright (c) Soumith Chintala 2016 and torchvision contributors. The source
implementation is BSD-3-Clause.

Official checkpoint: [ssd300_vgg16_coco-b556d3b4.pth](https://download.pytorch.org/models/ssd300_vgg16_coco-b556d3b4.pth)  
SHA-256: `b556d3b43ab6c3f63d81bfb8835fe8756ac22da664357da100dccf96b6a6b42d`  
Published COCO val2017 box mAP: 25.1.

### VGG-16 initialization lineage

The torchvision SSD recipe initializes its backbone from VGG-16 feature
weights released by the [Visual Geometry Group, University of
Oxford](https://www.robots.ox.ac.uk/~vgg/research/very_deep/) under
[CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). Attribution:
Karen Simonyan and Andrew Zisserman, "Very Deep Convolutional Networks for
Large-Scale Image Recognition," ICLR 2015.

## Modifications

Torchvision modified the VGG graph for SSD and trained the detector on COCO.
LibreYOLO adds v1.0 checkpoint metadata; learned tensors and state-dict keys
are unchanged. The native graph has exact eager parity for preprocessing, both
raw heads, default boxes, and final detections. ONNX Runtime prediction parity
is also verified. See `weights/convert_ssd_weights.py` in the
[LibreYOLO source repository](https://github.com/LibreYOLO/libreyolo).

## License

The checkpoint publisher did not attach a separate per-object license file.
This mirror applies the releasing project's BSD-3-Clause license on an
**implied**, not publisher-confirmed, basis. Torchvision warns that pretrained
models may have licenses or terms derived from training data and that users
must determine whether they have permission for their use case. COCO
annotations are CC BY 4.0; source images retain their individual Flickr terms.
The Oxford attribution above records the VGG initialization lineage and does
not claim that Oxford licensed the complete SSD checkpoint. See
[`LICENSE`](./LICENSE) and [`NOTICE`](./NOTICE).