Anycost GAN

video | paper | website

Anycost GANs for Interactive Image Synthesis and Editing

Ji Lin, Richard Zhang, Frieder Ganz, Song Han, Jun-Yan Zhu

MIT, Adobe Research, CMU

In CVPR 2021

Anycost GAN generates consistent outputs under various computational budgets.

Demo

Here, we can use the Anycost generator for interactive image editing. A full generator takes ~3s to render an image, which is too slow for editing. While with Anycost generator, we can provide a visually similar preview at 5x faster speed. After adjustment, we hit the "Finalize" button to synthesize the high-quality final output. Check here for the full demo.

Overview

Anycost generators can be run at diverse computation costs by using different channel and resolution configurations. Sub-generators achieve high output consistency compared to the full generator, providing a fast preview.

With (1) Sampling-based multi-resolution training, (2) adaptive-channel training, and (3) generator-conditioned discriminator, we achieve high image quality and consistency at different resolutions and channels.

Results

Anycost GAN (uniform channel version) supports 4 resolutions and 4 channel ratios, producing visually consistent images with different image fidelity.

The consistency retains during image projection and editing:

Usage

Getting Started

• Clone this repo:

git clone https://github.com/mit-han-lab/anycost-gan.git
cd anycost-gan

• Install PyTorch 1.7 and other dependeinces.

We recommend setting up the environment using Anaconda: conda env create -f environment.yml

Introduction Notebook

We provide a jupyter notebook example to show how to use the anycost generator for image synthesis at diverse costs: notebooks/intro.ipynb.

We also provide a colab version of the notebook: . Be sure to select the GPU as the accelerator in runtime options.

Interactive Demo

We provide an interactive demo showing how we can use anycost GAN to enable interactive image editing. To run the demo:

python demo.py

You can find a video recording of the demo here.

Using Pre-trained Models

To get the pre-trained generator, encoder, and editing directions, run:

import model

pretrained_type = 'generator'  # choosing from ['generator', 'encoder', 'boundary']
config_name = 'anycost-ffhq-config-f'  # replace the config name for other models
model.get_pretrained(pretrained_type, config=config_name)

We also provide the face attribute classifier (which is general for different generators) for computing the editing directions. You can get it by running:

model.get_pretrained('attribute-predictor')

The attribute classifier takes in the face images in FFHQ format.

After loading the Anycost generator, we can run it at a wide range of computational costs. For example:

from model.dynamic_channel import set_uniform_channel_ratio, reset_generator

g = model.get_pretrained('generator', config='anycost-ffhq-config-f')  # anycost uniform
set_uniform_channel_ratio(g, 0.5)  # set channel
g.target_res = 512  # set resolution
out, _ = g(...)  # generate image
reset_generator(g)  # restore the generator

For detailed usage and flexible-channel anycost generator, please refer to notebooks/intro.ipynb.

Model Zoo

Currently, we provide the following pre-trained generators, encoders, and editing directions. We will add more in the future.

For Anycost generators, by default, we refer to the uniform setting.

stylegan2-ffhq-config-f refers to the official StyleGAN2 generator converted from the repo.

Datasets

We prepare the FFHQ, CelebA-HQ, and LSUN Car datasets into a directory of images, so that it can be easily used with ImageFolder from torchvision. The dataset layout looks like:

├── PATH_TO_DATASET
│   ├── images
│   │   ├── 00000.png
│   │   ├── 00001.png
│   │   ├── ...

Due to the copyright issue, you need to download the dataset from official site and process them accordingly.

Evaluation

We provide the code to evaluate some metrics presented in the paper. Some of the code is written with horovod to support distributed evaluation and reduce the cost of inter-GPU communication, which greatly improves the speed. Check its website for a proper installation.

Fre ́chet Inception Distance (FID)

Before evaluating the FIDs, you need to compute the inception features of the real images using scripts like:

python tools/calc_inception.py \
    --resolution 1024 --batch_size 64 -j 16 --n_sample 50000 \
    --save_name assets/inceptions/inception_ffhq_res1024_50k.pkl \
    PATH_TO_FFHQ

or you can download the pre-computed inceptions from here and put it under assets/inceptions.

Then, you can evaluate the FIDs by running:

horovodrun -np N_GPU \
    python metrics/fid.py \
    --config anycost-ffhq-config-f \
    --batch_size 16 --n_sample 50000 \
    --inception assets/inceptions/inception_ffhq_res1024_50k.pkl
    # --channel_ratio 0.5 --target_res 512  # optionally using a smaller resolution/channel

Perceptual Path Lenght (PPL)

Similary, evaluting the PPL with:

horovodrun -np N_GPU \
    python metrics/ppl.py \
    --config anycost-ffhq-config-f

Attribute Consistency

Evaluating the attribute consistency by running:

horovodrun -np N_GPU \
    python metrics/attribute_consistency.py \
    --config anycost-ffhq-config-f \
    --channel_ratio 0.5 --target_res 512  # config for the sub-generator; necessary

Encoder Evaluation

To evaluate the performance of the encoder, run:

python metrics/eval_encoder.py \
    --config anycost-ffhq-config-f \
    --data_path PATH_TO_CELEBA_HQ

Training

The training code will be updated shortly.

Citation

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

@inproceedings{lin2021anycost,
  author    = {Lin, Ji and Zhang, Richard and Ganz, Frieder and Han, Song and Zhu, Jun-Yan},
  title     = {Anycost GANs for Interactive Image Synthesis and Editing},
  booktitle = {IEEE Conference on Computer Vision and Pattern Recognition (CVPR)},
  year      = {2021},
}

Related Projects

GAN Compression | Once for All | iGAN | StyleGAN2

Acknowledgement

We thank Taesung Park, Zhixin Shu, Muyang Li, and Han Cai for the helpful discussion. Part of the work is supported by NSF CAREER Award #1943349, Adobe, Naver Corporation, and MIT-IBM Watson AI Lab.

The codebase is build upon a PyTorch implementation of StyleGAN2: rosinality/stylegan2-pytorch. For editing direction extraction, we refer to InterFaceGAN.