# ABCNet v2: Adaptive Bezier-Curve Network for Real-time End-to-end Text Spotting

<div>
<a href="https://arxiv.org/abs/2105.03620">[arXiv paper]</a>
<a href="https://ieeexplore.ieee.org/document/9525302">[TPAMI paper]</a>
</div>

## Description

This is an implementation of [ABCNetV2](https://github.com/aim-uofa/AdelaiDet) based on [MMOCR](https://github.com/open-mmlab/mmocr/tree/dev-1.x), [MMCV](https://github.com/open-mmlab/mmcv), and [MMEngine](https://github.com/open-mmlab/mmengine).

**ABCNetV2**  contributions are four-fold: 1) For the first time, we adaptively fit arbitrarily-shaped text by a parameterized Bezier curve, which, compared with segmentation-based methods, can not only provide structured output but also controllable representation. 2) We design a novel BezierAlign layer for extracting accurate convolution features of a text instance of arbitrary shapes, significantly improving the precision of recognition over previous methods. 3) Different from previous methods, which often suffer from complex post-processing and sensitive hyper-parameters, our ABCNet v2 maintains a simple pipeline with the only post-processing non-maximum suppression (NMS). 4) As the performance of text recognition closely depends on feature alignment, ABCNet v2 further adopts a simple yet effective coordinate convolution to encode the position of the convolutional filters, which leads to a considerable improvement with negligible computation overhead. Comprehensive experiments conducted on various bilingual (English and Chinese) benchmark datasets demonstrate that ABCNet v2 can achieve state-of-the-art performance while maintaining very high efficiency.

<center>
<img src="https://user-images.githubusercontent.com/24622904/213096846-2557e0ac-ca18-4c4f-88c1-569107f48f9b.png">
</center>

## Usage

<!-- For a typical model, this section should contain the commands for training and testing. You are also suggested to dump your environment specification to env.yml by `conda env export > env.yml`. -->

### Prerequisites

- Python 3.7
- PyTorch 1.6 or higher
- [MIM](https://github.com/open-mmlab/mim)
- [MMOCR](https://github.com/open-mmlab/mmocr)

All the commands below rely on the correct configuration of `PYTHONPATH`, which should point to the project's directory so that Python can locate the module files. In `ABCNet/` root directory, run the following line to add the current directory to `PYTHONPATH`:

```shell
# Linux
export PYTHONPATH=`pwd`:$PYTHONPATH
# Windows PowerShell
$env:PYTHONPATH=Get-Location
```

if the data is not in `ABCNet/`, you can link the data into `ABCNet/`:

```shell
# Linux
ln -s ${DataPath} $PYTHONPATH
# Windows PowerShell
New-Item -ItemType SymbolicLink -Path $env:PYTHONPATH -Name data  -Target ${DataPath}
```

### Testing commands

In the current directory, run the following command to test the model:

```bash
mim test mmocr config/abcnet_v2/abcnet-v2_resnet50_bifpn_500e_icdar2015.py --work-dir work_dirs/ --checkpoint ${CHECKPOINT_PATH}
```

## Results

Here we provide the baseline version of ABCNet with ResNet50 backbone.

To find more variants, please visit the [official model zoo](https://github.com/aim-uofa/AdelaiDet/blob/master/configs/BAText/README.md).

|         Name          | Pretrained Model | E2E-None-Hmean | det-Hmean |                                                                   Download                                                                   |
| :-------------------: | :--------------: | :------------: | :-------: | :------------------------------------------------------------------------------------------------------------------------------------------: |
| v2-icdar2015-finetune |    SynthText     |     0.6628     |  0.8886   | [model](https://download.openmmlab.com/mmocr/textspotting/abcnet-v2/abcnet-v2_resnet50_bifpn/abcnet-v2_resnet50_bifpn_500e_icdar2015-5e4cc7ed.pth) |

## Citation

If you find ABCNetV2 useful in your research or applications, please cite ABCNetV2 with the following BibTeX entry.

```BibTeX
@ARTICLE{9525302,
  author={Liu, Yuliang and Shen, Chunhua and Jin, Lianwen and He, Tong and Chen, Peng and Liu, Chongyu and Chen, Hao},
  journal={IEEE Transactions on Pattern Analysis and Machine Intelligence},
  title={ABCNet v2: Adaptive Bezier-Curve Network for Real-time End-to-end Text Spotting},
  year={2021},
  volume={},
  number={},
  pages={1-1},
  doi={10.1109/TPAMI.2021.3107437}}
```

## Checklist

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- [x] Milestone 1: PR-ready, and acceptable to be one of the `projects/`.

  - [x] Finish the code

    <!-- The code's design shall follow existing interfaces and convention. For example, each model component should be registered into `mmocr.registry.MODELS` and configurable via a config file. -->

  - [x] Basic docstrings & proper citation

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  - [ ] Type hints and docstrings

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  - [ ] Code polishing

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  - [ ] Metafile.yml

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