GAN Fingerprints

Attributing Fake Images to GANs: Learning and Analyzing GAN Fingerprints

Ning Yu, Larry Davis, Mario Fritz
ICCV 2019

paper | project page | poster | media coverage in Chinese

GAN fingerprints demo

• The display window is refreshed every 5 seconds. Each refresh represents a testing case.
• The left two images are the testing input and its image fingerprint.
• The 1st row lists the learned model fingerprints of 5 sources, which are unchanged w.r.t refresh.
• The 2nd row lists the image fingerprint response to each model fingerprint.
• The 3rd row is a barplot of the response intensity w.r.t. each model fingerprint, the higher the stronger correlation, which also evidences for classification. The plot locates at the column corresponding to the predicted label.
• The model fingerprint title in green and the green barplot indicate the label ground truth.
• If there exists a red barplot, it means an incorrect classification. The red barplot indicates the predicted label, which is different from the label ground truth in green.

Abstract

Recent advances in Generative Adversarial Networks (GANs) have shown increasing success in generating photorealistic images. But they also raise challenges to visual forensics and model attribution. We present the first study of learning GAN fingerprints towards image attribution and using them to classify an image as real or GAN-generated. For GAN-generated images, we further identify their sources. Our experiments show that:

• Existence: GANs carry distinct model fingerprints and leave stable fingerprints in their generated images, which support image attribution;
• Uniqueness: Even minor differences in GAN training can result in different fingerprints, which enables fine-grained model authentication;
• Persistence: Fingerprints persist across different image frequencies and patches and are not biased by GAN artifacts;
• Immunizability: Fingerprint finetuning is effective in defending against five types of image perturbation attacks;
• Superiority: Comparisons also show our learned fingerprints consistently outperform several baselines in a variety of setups.

Prerequisites

• Linux
• NVIDIA GPU + CUDA 10.0 + CuDNN 7.5
• Python 3.6
• tensorflow-gpu 1.12
• To install the other Python dependencies, run pip3 install -r requirements.txt.

Datasets

To train GANs and our classifiers, we consider two real-world datasets:

• CelebA aligned and cropped face dataset. We crop each image centered at (x,y) = (89,121) with size 128x128 before training.
• LSUN bedroom scene dataset. We select the first 200k images, center-crop them to square size according to the shorter side length, and resize them to 128x128 before training.

GAN sources

For each dataset, we pre-train four GAN sources: ProGAN, SNGAN, CramerGAN, and MMDGAN

• ProGAN
  • Data preparation. Run, e.g.,

    cd ProGAN/
    python3 dataset_tool.py \
    create_from_images \
    datasets/celeba_align_png_cropped/ \
    ../celeba_align_png_cropped/
    

    where datasets/celeba_align_png_cropped/ is the output directory containing the prepared data format that enables efficient streaming, and ../celeba_align_png_cropped/ is the training dataset directory containing 128x128 png images.
  • Training. Run, e.g.,

    cd ProGAN/
    python3 run.py \
    --app train \
    --training_data_dir datasets/celeba_align_png_cropped/ \
    --out_model_dir models/celeba_align_png_cropped_seed_v0/ \
    --training_seed 0
    

    where
    • training_data_dir: The prepared training dataset directory that can be efficiently called by the code.
    • out_model_dir: The output directory containing trained models, training configureation, training log, and training snapshots.
    • training_seed: The random seed that differentiates training instances.
  • Pre-trained models. Download our pre-trained models here and put them at ProGAN/models/. The models named with _seed_v%d are only different in random seeds from each other.
  • Generation. With a pre-trained model, generate images of size 128x128 by running, e.g.,

    cd ProGAN/
    python3 run.py \
    --app gen \
    --model_path models/celeba_align_png_cropped.pkl \
    --out_image_dir gen/celeba_align_png_cropped/ \
    --num_pngs 10000 \
    --gen_seed 0
    

    where
    • model_path: The pre-trained GAN model.
    • out_image_dir: The outpupt directory containing generated images.
    • num_pngs: The number of generated images.
    • gen_seed: The random seed that differentiates generation instances.
• SNGAN
  • Data preparation. Run

    cd SNGAN/datasets/
    python3 celeba.py ../../celeba_align_png_cropped/
    

    Or

    cd SNGAN/datasets/
    python3 lsun_bedroom_200k.py ../../lsun_bedroom_train_200k_png/
    

    where ../../celeba_align_png_cropped/ and ../../lsun_bedroom_train_200k_png/ are the training dataset directories containing 128x128 png images.
  • Training. Run, e.g.,

    cd SNGAN/
    python3 train.py \
    --config_path configs/sn_projection_celeba.yml \
    --data_dir ../celeba_align_png_cropped/ \
    --results_dir models/celeba_align_png_cropped \
    --loaderjob 32
    

    where
    • config_path: The training configuration file. The yml file for LSUN is at configs/sn_projection_lsun_bedroom_200k.yml.
    • data_dir: The training dataset directory containing 128x128 png images.
    • results_dir: The output directory containing trained models, training configureations, training log, and training snapshots.
    • loaderjob: The number of parallel data loading processes.
  • Pre-trained models. Download our pre-trained models here and put them at SNGAN/models/.
  • Generation. With a pre-trained model, generate images of size 128x128 by running, e.g.,

    cd SNGAN/
    python3 evaluations/gen_images.py \
    --config_path configs/sn_projection_celeba.yml \
    --snapshot models/celeba_align_png_cropped.npz \
    --results_dir gen/celeba_align_png_cropped \
    --num_pngs 10000 \
    --seed 0 \
    

    where
    • config_path: The training configuration file. The yml file for LSUN is at configs/sn_projection_lsun_bedroom_200k.yml.
    • snapshot: The pre-trained GAN model.
    • results_dir: The outpupt directory containing generated images.
    • num_pngs: The number of generated images.
    • seed: The random seed that differentiates generation instances.
• CramerGAN
  • Training. Run, e.g.,

    cd CramerGAN/
    python3 gan/main.py \
    --is_train True \
    --dataset celebA \
    --data_dir ../celeba_align_png_cropped/ \
    --checkpoint_dir models/ \
    --sample_dir samples/ \
    --log_dir logs/ \
    --model cramer --name cramer_gan \
    --architecture g_resnet5 --output_size 128 --dof_dim 256 \
    --gradient_penalty 10. \
    --MMD_lr_scheduler \
    --random_seed 0
    

    where
    • dataset: The dataset ID.
    • data_dir: The training dataset directory containing 128x128 png images.
    • checkpoint_dir: The output directory containing trained models and training snapshots.
    • sample_dir: The output directory containing generated samples during training.
    • log_dir: The output directory containing training log.
    • random_seed: The random seed that differentiates training instances.
  • Pre-trained models. Download our pre-trained models here and put them at CramerGAN/models/cramer_gan/.
  • Generation. With a pre-trained model, generate images of size 128x128 by running, e.g.,

    cd CramerGAN/
    python3 gan/main.py \
    --dataset celebA \
    --data_dir ../celeba_align_png_cropped/ \
    --checkpoint_dir models/ \
    --output_dir_of_test_samples gen/celeba_align_png_cropped/ \
    --no_of_samples 10000 \
    --model cramer --name cramer_gan \
    --architecture g_resnet5 --output_size 128 --dof_dim 256 \
    --gradient_penalty 10. \
    --MMD_lr_scheduler \
    --random_seed 0
    

    where
    • output_dir_of_test_samples: The outpupt directory containing generated images.
    • no_of_samples: The number of generated images.
• MMDGAN (The same API as CramerGAN)
  • Training. Run, e.g.,

    cd MMDGAN/
    python3 gan/main.py \
    --is_train True \
    --dataset celebA \
    --data_dir ../celeba_align_png_cropped/ \
    --checkpoint_dir models/ \
    --sample_dir samples/ \
    --log_dir logs/ \
    --model mmd --name mmd --kernel mix_rq_1dot \
    --architecture g_resnet5 --output_size 128 --dof_dim 16 \
    --gradient_penalty 1. --L2_discriminator_penalty 1. \
    --MMD_lr_scheduler \
    --random_seed 0
    

  • Pre-trained models. Download our pre-trained models here and put them at MMDGAN/models/mmd/.
  • Generation. With a pre-trained model, generate images of size 128x128 by running, e.g.,

    cd MMDGAN/
    python3 gan/main.py \
    --dataset celebA \
    --data_dir ../celeba_align_png_cropped/ \
    --checkpoint_dir models/ \
    --output_dir_of_test_samples gen/celeba_align_png_cropped/ \
    --no_of_samples 10000 \
    --model mmd --name mmd --kernel mix_rq_1dot \
    --architecture g_resnet5 --output_size 128 --dof_dim 16 \
    --gradient_penalty 1. --L2_discriminator_penalty 1. \
    --MMD_lr_scheduler \
    --random_seed 0
    

GAN classifier

Given images of size 128x128 from real dataset or generated by different GANs, we train a classifier to attribute their sources. The code is modified from ProGAN.

• Data preparation. Run, e.g.,

  cd classifier/
  python3 data_preparation.py \
  --in_dir ../GAN_classifier_datasets/train/ \
  --out_dir datasets/train/
  

  where
  • in_dir: The input directory containing subdirectories of images. Each subdirectory represents a data source, either from the real dataset or generated by a GAN.
  • out_dir: The output directory containing the prepared data format and its source label format that enable efficient streaming.
• Training. Run, e.g.,

  cd classifier/
  python3 run.py \
  --app train \
  --training_data_dir datasets/training/ \
  --validation_data_dir datasets/validation/ \
  --out_model_dir models/GAN_classifier/ \
  --training_seed 0
  

  where
  • training_data_dir: The prepared training dataset directory that can be efficiently called by the code.
  • validation_data_dir: The prepared validation dataset directory that can be efficiently called by the code.
  • out_model_dir: The output directory containing trained models, training configureation, training log, and training snapshots.
  • training_seed: The random seed that differentiates training instances.
• Pre-trained models. Download our pre-trained models here and put them at classifier/models/. They separately apply to the two datasets and differentiate either from the 5 sources (1 real + 4 GAN architectures) or from the 11 sources (1 real + 10 ProGANs pre-trained with different random seeds).
• Testing. Run, e.g.,

  cd classifier/
  python3 run.py \
  --app test \
  --model_path models/CelebA_ProGAN_SNGAN_CramerGAN_MMDGAN_128.pkl \
  --testing_data_path ../GAN_classifier_datasets/test/
  

  where
  • model_path: The pre-trained GAN model.
  • testing_data_path: The path of testing image file or the directory containing a collection of testing images. There is no need to execute data preparation for testing image(s).

GAN classifier visNet variant (fingerprint visualization)

This is another variant from the above regular GAN classifier. Given images of size 128x128 from real dataset or generated by different GANs, besides training a classifier to attribute their sources, we simultaneously learn to expose fingerprints for each image and for each source. The fingerprints are also in the size of 128x128. The code is modified from ProGAN and has a similar API to the above regular GAN classifier.

• Data preparation. Run, e.g.,

  cd classifier_visNet/
  python3 data_preparation.py \
  --in_dir ../GAN_classifier_datasets/train/ \
  --out_dir datasets/train/
  

• Training. Run, e.g.,

  cd classifier_visNet/
  python3 run.py \
  --app train \
  --training_data_dir datasets/training/ \
  --validation_data_dir datasets/validation/ \
  --out_model_dir models/GAN_classifier/ \
  --training_seed 0
  

• Pre-trained models. Download our pre-trained models here and put them at classifier_visNet/models/.
• Testing. Run, e.g.,

  cd classifier_visNet/
  python3 run.py \
  --app test \
  --model_path models/CelebA_ProGAN_SNGAN_CramerGAN_MMDGAN_128.pkl \
  --testing_data_path ../GAN_classifier_datasets/test/ \
  --out_fingerprint_dir fingerprints/GAN_classifier_visNet/
  

  where
  • out_fingerprint_dir: The output directory containing model fingerprints, image fingerprint(s), and image fingerprints masked(re-weighted) by each model fingerprint.

Citation

@inproceedings{yu2019attributing,
    author = {Yu, Ning and Davis, Larry and Fritz, Mario},
    title = {Attributing Fake Images to GANs: Learning and Analyzing GAN Fingerprints},
    booktitle = {IEEE International Conference on Computer Vision (ICCV)},
    year = {2019}
}

Acknowledgement

• This research is partially funded by DARPA MediFor program under cooperative agreement FA87501620191. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the DARPA.
• We acknowledge the Maryland Advanced Research Computing Center for providing computing resources.
• We thank Hao Zhou for helping with the relighting experiments.
• We also thank Yaser Yacoob and Abhinav Shrivastava for constructive advice in general.
• We express gratitudes to the ProGAN repository as we benefit a lot from their code.