# Swin Transformer
[](https://paperswithcode.com/sota/object-detection-on-coco?p=swin-transformer-hierarchical-vision)
[](https://paperswithcode.com/sota/instance-segmentation-on-coco?p=swin-transformer-hierarchical-vision)
[](https://paperswithcode.com/sota/object-detection-on-coco-minival?p=swin-transformer-hierarchical-vision)
[](https://paperswithcode.com/sota/instance-segmentation-on-coco-minival?p=swin-transformer-hierarchical-vision)
[](https://paperswithcode.com/sota/semantic-segmentation-on-ade20k?p=swin-transformer-hierarchical-vision)
[](https://paperswithcode.com/sota/semantic-segmentation-on-ade20k-val?p=swin-transformer-hierarchical-vision)
By [Ze Liu](https://github.com/zeliu98/)\*, [Yutong Lin](https://github.com/impiga)\*, [Yue Cao](http://yue-cao.me)\*, [Han Hu](https://ancientmooner.github.io/)\*, [Yixuan Wei](https://github.com/weiyx16), [Zheng Zhang](https://stupidzz.github.io/), [Stephen Lin](https://scholar.google.com/citations?user=c3PYmxUAAAAJ&hl=en) and [Baining Guo](https://www.microsoft.com/en-us/research/people/bainguo/).
This repo is the official implementation of ["Swin Transformer: Hierarchical Vision Transformer using Shifted Windows"](https://arxiv.org/pdf/2103.14030.pdf). It currently includes code and models for the following tasks:
> **Image Classification**: Included in this repo. See [get_started.md](get_started.md) for a quick start.
> **Object Detection and Instance Segmentation**: See [Swin Transformer for Object Detection](https://github.com/SwinTransformer/Swin-Transformer-Object-Detection).
> **Semantic Segmentation**: See [Swin Transformer for Semantic Segmentation](https://github.com/SwinTransformer/Swin-Transformer-Semantic-Segmentation).
## Updates
***04/12/2021***
Initial commits:
1. Pretrained models on ImageNet-1K ([Swin-T-IN1K](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_tiny_patch4_window7_224.pth), [Swin-S-IN1K](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_small_patch4_window7_224.pth), [Swin-B-IN1K](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_base_patch4_window7_224.pth)) and ImageNet-22K ([Swin-B-IN22K](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_base_patch4_window7_224_22k.pth), [Swin-L-IN22K](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_large_patch4_window7_224_22k.pth)) are provided.
2. The supported code and models for ImageNet-1K image classification, COCO object detection and ADE20K semantic segmentation are provided.
3. The cuda kernel implementation for the [local relation layer](https://arxiv.org/pdf/1904.11491.pdf) is provided in branch [LR-Net](https://github.com/microsoft/Swin-Transformer/tree/LR-Net).
## Introduction
**Swin Transformer** (the name `Swin` stands for **S**hifted **win**dow) is initially described in [arxiv](https://arxiv.org/abs/2103.14030), which capably serves as a
general-purpose backbone for computer vision. It is basically a hierarchical Transformer whose representation is
computed with shifted windows. The shifted windowing scheme brings greater efficiency by limiting self-attention
computation to non-overlapping local windows while also allowing for cross-window connection.
Swin Transformer achieves strong performance on COCO object detection (`58.7 box AP` and `51.1 mask AP` on test-dev) and
ADE20K semantic segmentation (`53.5 mIoU` on val), surpassing previous models by a large margin.
## Main Results on ImageNet with Pretrained Models
**ImageNet-1K and ImageNet-22K Pretrained Models**
| name | pretrain | resolution |acc@1 | acc@5 | #params | FLOPs | FPS| 22K model | 1K model |
| :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: |:---: |:---: |
| Swin-T | ImageNet-1K | 224x224 | 81.2 | 95.5 | 28M | 4.5G | 755 | - | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_tiny_patch4_window7_224.pth)/[baidu](https://pan.baidu.com/s/156nWJy4Q28rDlrX-rRbI3w) |
| Swin-S | ImageNet-1K | 224x224 | 83.2 | 96.2 | 50M | 8.7G | 437 | - | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_small_patch4_window7_224.pth)/[baidu](https://pan.baidu.com/s/1KFjpj3Efey3LmtE1QqPeQg) |
| Swin-B | ImageNet-1K | 224x224 | 83.5 | 96.5 | 88M | 15.4G | 278 | - | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_base_patch4_window7_224.pth)/[baidu](https://pan.baidu.com/s/16bqCTEc70nC_isSsgBSaqQ) |
| Swin-B | ImageNet-1K | 384x384 | 84.5 | 97.0 | 88M | 47.1G | 85 | - | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_base_patch4_window12_384.pth)/[baidu](https://pan.baidu.com/s/1xT1cu740-ejW7htUdVLnmw) |
| Swin-B | ImageNet-22K | 224x224 | 85.2 | 97.5 | 88M | 15.4G | 278 | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_base_patch4_window7_224_22k.pth)/[baidu](https://pan.baidu.com/s/1y1Ec3UlrKSI8IMtEs-oBXA) | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_base_patch4_window7_224_22kto1k.pth)/[baidu](https://pan.baidu.com/s/1n_wNkcbRxVXit8r_KrfAVg) |
| Swin-B | ImageNet-22K | 384x384 | 86.4 | 98.0 | 88M | 47.1G | 85 | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_base_patch4_window12_384_22k.pth)/[baidu](https://pan.baidu.com/s/1vwJxnJcVqcLZAw9HaqiR6g) | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_base_patch4_window12_384_22kto1k.pth)/[baidu](https://pan.baidu.com/s/1caKTSdoLJYoi4WBcnmWuWg) |
| Swin-L | ImageNet-22K | 224x224 | 86.3 | 97.9 | 197M | 34.5G | 141 | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_large_patch4_window7_224_22k.pth)/[baidu](https://pan.baidu.com/s/1pws3rOTFuOebBYP3h6Kx8w) | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_large_patch4_window7_224_22kto1k.pth)/[baidu](https://pan.baidu.com/s/1NkQApMWUhxBGjk1ne6VqBQ) |
| Swin-L | ImageNet-22K | 384x384 | 87.3 | 98.2 | 197M | 103.9G | 42 | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_large_patch4_window12_384_22k.pth)/[baidu](https://pan.baidu.com/s/1sl7o_bJA143OD7UqSLAMoA) | [github](https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_large_patch4_window12_384_22kto1k.pth)/[baidu](https://pan.baidu.com/s/1X0FLHQyPOC6Kmv2CmgxJvA) |
Note: access code for `baidu` is `swin`.
## Main Results on Downstream Tasks
**COCO Object Detection (2017 val)**
| Backbone | Method | pretrain | Lr Schd | box mAP | mask mAP | #params | FLOPs |
| :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
| Swin-T | Mask R-CNN | ImageNet-1K | 3x | 46.0 | 41.6 | 48M | 267G |
| Swin-S | Mask R-CNN | ImageNet-1K | 3x | 48.5 | 43.3 | 69M | 359G |
| Swin-T | Cascade Mask R-CNN | ImageNet-1K | 3x | 50.4 | 43.7 | 86M | 745G |
| Swin-S | Cascade Mask R-CNN | ImageNet-1K | 3x | 51.9 | 45.0 | 107M | 838G |
| Swin-B | Cascade Mask R-CNN | ImageNet-1K | 3x | 51.9 | 45.0 | 145M | 982G |
| Swin-T | RepPoints V2 | ImageNet-1K | 3x | 50.0 | - | 45M | 283G |
| Swin-T | Mask RepPoints V2 | ImageNet-1K | 3x | 50.3 | 43.6 | 47M | 292G |
| Swin-B | HTC++ | ImageNet-22K | 6x | 56.4 | 49.1 | 160M | 1043G |
| Swin-L | HTC++ | ImageNet-22K | 3x | 57.1 | 49.5 | 284M | 1470G |
| Swin-L | HTC++* | ImageNet-22K | 3x | 58.0 | 50.4 | 284M | - |
Note: * indicates multi-scale testing.
**ADE20K Semantic Segmentation (val)**
| Backbone | Method | pretrain | Crop Size | Lr Schd | mIoU | mIoU (ms+flip) | #params | FLOPs |
| :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
| Swin-T | UPerNet | ImageNet-1K | 512x512 | 160K | 44.51 | 45.81 | 60M | 945G |
| Swin-S | UperNet | ImageNet-1K | 512x512 | 160K | 47.64 | 49.47 | 81M | 1038G |
| Swin-B | UperNet | ImageNet-1K | 512x512 | 160K | 48.13 | 49.72 | 121M | 1188G |
| Swin-B | UPerNet | ImageNet-22K | 640x640 | 160K | 50.04 | 51.66 | 121M | 1841G |
| Swin-L | UperNet | ImageNet-22K | 640x640 | 160K | 52.05 | 53.53 | 234M | 3230G |
## Citing Swin Transformer
```
@article{liu2021Swin,
title={Swin Transformer: Hierarchical Vision Transformer using Shifted Windows},
author={Liu, Ze and Lin, Yutong and Cao, Yue and Hu, Han and Wei, Yixuan and Zhang, Zheng and Lin, Stephen and Guo, Baining},
journal={arXiv preprint arXiv:2103.14030},
year={2021}
}
```
## Getting Started
- For **Image Classification**, please see [get_started.md](get_started.md) for detailed instructions.
- For **Object Detection and Instance Segmentation**, please see [Swin Transformer for Object Detection](https://github.com/SwinTransformer/Swin-Transformer-Object-Detection).
- For **Semantic Segmentation**, please see [Swin Transformer for Semantic Segmentation](https://github.com/SwinTransformer/Swin-Transformer-Semantic-Segmentation).
## Third-party Usage and Experiments
***In this pargraph, we cross link third-party repositories which use Swin and report results. You can let us know by raising an issue***
(`Note please report accuracy numbers and provide trained models in your new repository to facilitate others to get sense of correctness and model behavior`)
[04/14/2021] Swin for RetinaNet in Detectron: https://github.com/xiaohu2015/SwinT_detectron2.
[04/16/2021] Included in a famous model zoo: https://github.com/rwightman/pytorch-image-models.
[04/20/2021] Swin-Transformer classifier inference using TorchServe: https://github.com/kamalkraj/Swin-Transformer-Serve
## Contributing
This project welcomes contributions and suggestions. Most contributions require you to agree to a
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the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com.
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This project has adopted the [Microsoft Open Source Code of Conduct](https://opensource.microsoft.com/codeofconduct/).
For more information see the [Code of Conduct FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or
contact [opencode@microsoft.com](mailto:opencode@microsoft.com) with any additional questions or comments.
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