GAN Ensembling

Project Page | Paper | Bibtex

Ensembling with Deep Generative Views.
Lucy Chai, Jun-Yan Zhu, Eli Shechtman, Phillip Isola, Richard Zhang
CVPR 2021

Prerequisites

• Linux
• Python 3
• NVIDIA GPU + CUDA CuDNN

Table of Contents:

1. Colab - run a limited demo version without local installation
2. Setup - download required resources
   
3. Quickstart - short demonstration code snippet
   
4. Notebooks - jupyter notebooks for visualization
   
5. Pipeline - details on full pipeline
   

Colab

This Colab Notebook demonstrates the basic latent code perturbation and classification procedure in a simplified setting on the aligned cat dataset.

Setup

• Clone this repo:

git clone https://github.com/chail/gan-ensembling.git
cd gan-ensembling

• Install dependencies:

  • we provide a Conda environment.yml file listing the dependencies. You can create the Conda environment using:

   conda env create -f environment.yml

• Download resources:

  • We provide a script for downloading associated resources.
  • It will download precomputed latent codes (cat: 291M, car: 121M, celebahq: 1.8G, cifar10: 883M), a subset of trained models (592M), precomputed results (1.3G), and associated libraries.
  • Fetch the resources by running

   bash resources/download_resources.sh

  • Note, Optional: to run the StyleGAN ID-invert models, the models need to be downloaded separately. Follow the directions here to obtain styleganinv_ffhq256_encoder.pth and styleganinv_ffhq256_encoder.pth, and place them in models/pretrain
  • Note, Optional: the download script downloads a subset of the pretrained models for the demo notebook. For further experiments, the additional pretrained models (total 7.0G) can be downloaded here; it includes 40 binary face attribute classifiers, and classifiers trained on the different perturbation methods for the remaining datasets.

• Download external datasets:

  • CelebA-HQ: Follow the instructions here to create the CelebA-HQ dataset and place CelebA-HQ images in directory dataset/celebahq/images/images.
  • Cars: This dataset is a subset of Cars196. Download the images from here and the devkit from here. (We are subsetting their training images into train/test/val partitions). Place the images in directory dataset/cars/images/images and the devkit in dataset/cars/devkit.
  • The processed and aligned cat images are downloaded with the above resources, and cifar10 dataset is downloaded via the PyTorch wrapper.

An example of the directory organization is below:

dataset/celebahq/
	images/images/
		000004.png
		000009.png
		000014.png
		...
	latents/
	latents_idinvert/
dataset/cars/
	devkit/
		cars_meta.mat
		cars_test_annos.mat
		cars_train_annos.mat
		...
	images/images/
		00001.jpg
		00002.jpg
		00003.jpg
		...
	latents/
dataset/catface/
	images/
	latents/
dataset/cifar10/
	cifar-10-batches-py/
	latents/

Quickstart

Once the datasets and precomputed resources are downloaded, the following code snippet demonstrates how to perturb GAN images. Additional examples are contained in notebooks/demo.ipynb.

import data
from networks import domain_generator

dataset_name = 'celebahq'
generator_name = 'stylegan2'
attribute_name = 'Smiling'
val_transform = data.get_transform(dataset_name, 'imval')
dset = data.get_dataset(dataset_name, 'val', attribute_name, load_w=True, transform=val_transform)
generator = domain_generator.define_generator(generator_name, dataset_name)

index = 100
original_image = dset[index][0][None].cuda()
latent = dset[index][1][None].cuda()
gan_reconstruction = generator.decode(latent)
mix_latent = generator.seed2w(n=4, seed=0)
perturbed_im = generator.perturb_stylemix(latent, 'fine', mix_latent, n=4)

Notebooks

Important: First, set up symlinks required for notebooks: bash notebooks/setup_notebooks.sh, and add the conda environment to jupyter kernels: python -m ipykernel install --user --name gan-ensembling.

The provided notebooks are:

1. notebooks/demo.ipynb: basic usage example
2. notebooks/evaluate_ensemble.ipynb: plot classification test accuracy as a function of ensemble weight
3. notebooks/plot_precomputed_evaluations.ipynb: notebook to generate figures in paper

Full Pipeline

The full pipeline contains three main parts:

1. optimize latent codes
2. train classifiers
3. evaluate the ensemble of GAN-generated images.

Examples for each step of the pipeline are contained in the following scripts:

bash scripts/optimize_latent/examples.sh
bash scripts/train_classifier/examples.sh
bash scripts/eval_ensemble/examples.sh

To add to the pipeline:

• Data: in the data/ directory, add the dataset in data/__init__.py and create the dataset class and transformation functions. See data/data_*.py for examples.
• Generator: modify networks/domain_generators.py to add the generator in domain_generators.define_generator. The perturbation ranges for each dataset and generator are specified in networks/perturb_settings.py.
• Classifier: modify networks/domain_classifiers.py to add the classifier in domain_classifiers.define_classifier

Acknowledgements

We thank the authors of these repositories:

• Gan Seeing for GAN and visualization utilities
• StyleGAN 2 Pytorch for pytorch implementation of StyleGAN 2 and pretrained models (license)
• Stylegan 2 ADA Pytorch for the class-conditional StyleGAN 2 CIFAR10 generator (license)
• StyleGAN In-domain inversion for the in-domain stylegan generator and encoder (license)
• Pytorch CIFAR for CIFAR10 classification (license)
• Latent Composition for some code and remaining encoders (license)
• Cat dataset images are from the Oxford-IIIT Pet Dataset (license), aligned using the Frederic landmark detector (license).

Citation

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

@inproceedings{chai2021ensembling,
  title={Ensembling with Deep Generative Views.},
  author={Chai, Lucy and Zhu, Jun-Yan and Shechtman, Eli and Isola, Phillip and Zhang, Richard},
  booktitle={CVPR},
  year={2021}
 }