CycleGAN

[project page] [paper]

Torch implementation for learning an image-to-image translation (i.e. pix2pix) without input-output pairs, for example:

Unpaired Image-to-Image Translation using Cycle-Consistent Adversarial Networks
Jun-Yan Zhu*, Taesung Park*, Phillip Isola, Alexei A. Efros
Berkeley AI Research Lab, UC Berkeley
In arxiv, 2017. (* equal contributions)

This package includes CycleGAN, pix2pix, as well as other methods like BiGAN/ALI and Apple's paper S+U learning.
The code was written by Jun-Yan Zhu and Taesung Park.
The PyTorch version is coming soon.

Applications

Monet Paintings to Photos

Collection Style Transfer

Object Transfiguration

Season Transfer

Photo Enhancement: iPhone photo to DSLR photo

Prerequisites

• Linux or OSX
• NVIDIA GPU + CUDA CuDNN (CPU mode and CUDA without CuDNN may work with minimal modification, but untested)
• For MAC users, you need the Linux/GNU commands gfind and gwc, which can be installed with brew install findutils coreutils.

Getting Started

Installation

• Install torch and dependencies from https://github.com/torch/distro
• Install torch packages nngraph, class, display

luarocks install nngraph
luarocks install class
luarocks install https://raw.githubusercontent.com/szym/display/master/display-scm-0.rockspec

• Clone this repo:

git clone https://github.com/junyanz/CycleGAN
cd CycleGAN

Apply a Pre-trained Model

• Download the test photos (taken by Alexei Efros):

bash ./datasets/download_dataset.sh ae_photos

• Download the pre-trained model style_cezanne:

bash ./pretrained_models/download_model.sh style_cezanne

• Now, let's generate Paul Cézanne style images:

DATA_ROOT=./datasets/ae_photos name=style_cezanne_pretrained model=one_direction_test phase=test loadSize=256 fineSize=256 resize_or_crop="scale_width" th test.lua

The test results will be saved to ./results/style_cezanne_pretrained/latest_test/index.html.
Please refer to Model Zoo for more pre-trained models. ./examples/test_vangogh_style_on_ae_photos.sh is an example script that downloads the pretrained Van Gogh style network and runs it on Alexei's photos.

Train

• Download a dataset (e.g. zebra and horse images from ImageNet):

bash ./datasets/download_dataset.sh horse2zebra

• Train a model:

DATA_ROOT=./datasets/horse2zebra name=horse2zebra_model th train.lua

• (CPU only) The same training command without using a GPU or CUDNN. Setting the environment variables gpu=0 cudnn=0 forces CPU only

DATA_ROOT=./datasets/horse2zebra name=horse2zebra_model gpu=0 cudnn=0 th train.lua

• (Optionally) start the display server to view results as the model trains. (See Display UI for more details):

th -ldisplay.start 8000 0.0.0.0

Test

• Finally, test the model:

DATA_ROOT=./datasets/horse2zebra name=horse2zebra_model phase=test th test.lua

The test results will be saved to a html file here: ./results/horse2zebra_model/latest_test/index.html.

Model Zoo

Download the pre-trained models with the following script. The model will be saved to ./checkpoints/model_name/latest_net_G.t7.

bash ./pretrained_models/download_model.sh model_name

• orange2apple (orange -> apple) and apple2orange: trained on ImageNet categories apple and orange.
• horse2zebra (horse -> zebra) and zebra2horse (zebra -> horse): trained on ImageNet categories horse and zebra.
• style_monet (landscape photo -> Monet painting style), style_vangogh (landscape photo -> Van Gogh painting style), style_ukiyoe (landscape photo -> Ukiyo-e painting style), style_cezanne (landscape photo -> Cezanne painting style): trained on paintings and Flickr landscape photos.
• monet2photo (Monet paintings -> real landscape): trained on paintings and Flickr landscape photographs.
• cityscapes_photo2label (street scene -> label) and cityscapes_label2photo (label -> street scene): trained on the Cityscapes dataset.
• map2sat (map -> aerial photo) and sat2map (aerial photo -> map): trained on Google maps.
• iphone2dslr_flower (iPhone photos of flower -> DSLR photos of flower): trained on Flickr photos.

Training and Test Details

To train a model,

DATA_ROOT=/path/to/data/ name=expt_name th train.lua

Models are saved to ./checkpoints/expt_name (can be changed by passing checkpoint_dir=your_dir in train.lua).
See opt_train in options.lua for additional training options.

To test the model,

DATA_ROOT=/path/to/data/ name=expt_name which_direction='AtoB' phase=test th test.lua

This will run the model named expt_name in both directions on all images in /path/to/data/testA and /path/to/data/testB.
If which_direction is 'BtoA', the two sets A and B of the datasets are flipped. Result images, and a webpage to view them, are saved to ./results/expt_name (can be changed by passing results_dir=your_dir in test.lua).
See opt_test in options.lua for additional test options. Please use model=one_direction_test if you only would like to generate outputs of the trained network in only one direction.

Datasets

Download the datasets using the following script:

bash ./datasets/download_dataset.sh dataset_name

• facades: 400 images from the CMP Facades dataset.
• cityscapes: 2975 images from the Cityscapes training set.
• maps: 1096 training images scraped from Google Maps.
• horse2zebra: 939 horse images and 1177 zebra images downloaded from ImageNet using keywords wild horse and zebra
• apple2orange: 996 apple images and 1020 orange images downloaded from ImageNet using keywords apple and navel orange.
• summer2winter_yosemite: 1273 summer Yosemite images and 854 winter Yosemite images were downloaded using Flickr API. See more details in our paper.
• monet2photo, vangogh2photo, ukiyoe2photo, cezanne2photo: The art images were downloaded from Wikiart. The real photos are downloaded from Flickr using combination of tags landscape and landscapephotography. The training set size of each class is Monet:1074, Cezanne:584, Van Gogh:401, Ukiyo-e:1433, Photographs:6853.
• iphone2dslr_flower: both classe of images were downlaoded from Flickr. The training set size of each class is iPhone:1813, DSLR:3316. See more details in our paper.

Display UI

Optionally, for displaying images during training and test, use the display package.

• Install it with: luarocks install https://raw.githubusercontent.com/szym/display/master/display-scm-0.rockspec
• Then start the server with: th -ldisplay.start
• Open this URL in your browser: http://localhost:8000

By default, the server listens on localhost. Pass 0.0.0.0 to allow external connections on any interface:

th -ldisplay.start 8000 0.0.0.0

Then open http://(hostname):(port)/ in your browser to load the remote desktop.

Setup Training and Test data

To train CycleGAN model on your own datasets, you need to create a data folder with two subdirectories trainA and trainB that contain images from domain A and B. You can test your model on your training set by setting phase='train' in test.lua. You can also create subdirectories like testA and testB if you have additional test data.

You should not expect our method to work on any combination of two random datasets (e.g. cats<->keyboards). From our experiments, we find it works better if two datasets share similar visual content. For example, landscape painting<->landscape photographs works much better than portrait painting <-> landscape photographs. zebras<->horses achieves compelling results while cats<->dogs completely fails. See the following section for more discussion.

Failure cases

Several typical failure cases are shown here. On translation tasks that involve color and texture changes, like many of those reported above, the method often succeeds. We have also explored tasks that require geometric changes, with little success. For example, on the task of dog<->cat transfiguration, the learned translation degenerates to making minimal changes to the input. We also observe a lingering gap between the results achievable with paired training data and those achieved by our unpaired method. In some cases, this gap may be very hard -- or even impossible,-- to close: for example, our method sometimes permutes the labels for tree and building in the output of the cityscapes photos->labels task.

Citation

If you use this code for your research, please cite our paper:

@article{CycleGAN2017,
  title={Unpaired Image-to-Image Translation using Cycle-Consistent Adversarial Networks},
  author={Zhu, Jun-Yan and Park, Taesung and Isola, Phillip and Efros, Alexei A},
  journal={arXiv preprint arXiv:1703.10593},
  year={2017}
}

Related Projects:

pix2pix: Image-to-image translation using conditional adversarial nets
iGAN: Interactive Image Generation via Generative Adversarial Networks

Cat Paper Collection

If you love cats, and love reading cool graphics, vision, and learning papers, please check out the Cat Paper Collection:
[Github] [Webpage]

Acknowledgments

Code borrows from pix2pix and DCGAN. The data loader is modified from DCGAN and Context-Encoder. The generative network is adopted from neural-style with Instance Normalization.