We implement FreeAnchor in 3D detection systems and provide their first results with PointPillars on nuScenes dataset.
With the implemented `FreeAnchor3DHead`, a PointPillar detector with a big backbone (e.g., RegNet-3.2GF) achieves top performance
on the nuScenes benchmark.
```
@inproceedings{zhang2019freeanchor,
title = {{FreeAnchor}: Learning to Match Anchors for Visual Object Detection},
author = {Zhang, Xiaosong and Wan, Fang and Liu, Chang and Ji, Rongrong and Ye, Qixiang},
booktitle = {Neural Information Processing Systems},
year = {2019}
}
```
## Usage
### Modify config
As in the [baseline config](hv_pointpillars_fpn_sbn-all_free-anchor_4x8_2x_nus-3d.py), we only need to replace the head of an existing one-stage detector to use FreeAnchor head.
Since the config is inherit from a common detector head, `_delete_=True` is necessary to avoid conflicts.
The hyperparameters are specifically tuned according to the original paper.