Hidden in Plain Sight: Subgroup Shifts Escape OOD Detection

This is the code used in the MIDL 2022 submission "Hidden in Plain Sight: Subgroup Shifts Escape OOD Detection" (https://openreview.net/pdf?id=aZgiUNye2Cz).

Prerequisites

• Python environment

  > pip install -e .
  

  Note that for experiments on histopathology data, we use our custom fork of the wilds package. You don't need to worry about this if you install from the setup file directly.

• Data

  For both MNIST and Camelyon17, the data is automatically to data_root directory specified in config the first time the dataset is created. For Camelyon17, this may take a while.

• Task classifiers (for ODIN and MUKS)

  For the individual OOD detection as well as the MUKS hypothesis tests, you need trained task classifiers. These are downloaded automatically to the paths specified in the config file (key task_classifier_path).

  If you want to train task classifiers yourself, follow the instructions below

Experiments

Configurations

All experiments are fully specified by config files which can be found in ./config. Please adjust paths in there as needed.

The provided config templates assume the following coarse project structure:

• ./experiments: all your experiments go here
• ./data: all the raw data is here.

Run individual configurations

To run an individual configuration, you can do

# For population-level subgroup shift detection
python ./scripts/run_main_exp.py --exp_dir EXP_DIR --config_file CONFIG_FILE --eval_splits test

# For individual OOD detection
python ./scripts/run_odin_exp.py --exp_dir EXP_DIR --config_file CONFIG_FILE

A folder will be placed inside exp_dir named after a unique hash of the config file. Trained models and results will be placed there.

Reproduce paper experiments

To reproduce the experiments in the paper, run

python ./scripts/run_all_experiments.py --exp_base_dir ./experiments

Adjust the experiment directory as needed. If you have access to a slurm cluster, you can use the options --slurm True --slurm_email your@email.com [+slurm resource configuration] to accelerate the compute heavy operations.

Note: Make sure all data and models are downloaded before running parallel experiments, as this will result in conflicts due to simultaneous downloads. You can do this by running

python ./scripts/download.py --data_mnist DATA_PATH_MNIST --data_camelyon DATA_PATH_CAMELYON --model_mnist MODEL_PATH_MNIST --model_mnist_no5 MODEL_PATH_MNIST_NO5 --model_camelyon MODEL_PATH_CAMELYON

Here. The paths should correspond to the paths specified in the config files.

Once the jobs are completed, you can generate the paper figures with

python ./scripts/plot_results.py

Check whether default paths work for you (e.g. with python plot_results.py --help), otherwise pass the correct ones.

Citation

If you use this code, please cite

@inproceedings{koch2022subgroup,
  title      = {Hidden in Plain Sight: Subgroup Shifts Escape OOD Detection},
  author     = {Koch, Lisa M and Sch{\"u}rch, Christian M and Gretton, Arthur and Berens, Philipp},
  booktitle  = {Proc. Medical Imaging with Deep Learning (MIDL) - under review},
  year       = {2022},
}

Please also note that code segments from related work were used. If use them, please also cite:

@inproceedings{liu2020deepkernel,
  title      = {Learning {Deep} {Kernels} for {Non}-{Parametric} {Two}-{Sample} {Tests}},
  author     = {Liu, Feng and Xu, Wenkai and Lu, Jie and Zhang, Guangquan and Gretton, Arthur and Sutherland, Danica J},
  booktitle  = {Proc. International Conference on Machine Learning (ICML)},
  year       = {2020},
}

@inproceedings{liang2018odin,
  title      = {Enhancing {The} {Reliability} of {Out}-of-distribution {Image} {Detection} in {Neural} {Networks}},
  author     = {Liang, Shiyu and Li, Yixuan and Srikant, R.},
  booktitle  = {Proc. International Conference on Learning Representations (ICLR)},
  year       = {2018}
}

Other

Train task classifiers yourself

If you want to train task classifiers yourself, follow the instructions below. Note: Set the correct paths to the classification models in the config and script parameters.

• MNIST: Use the training script provided

  > python ./scripts/train_mnist_classifier.py --config_file CONFIG_FILE
  

• Camelyon17: We used the wilds package for training a Densenet on Camelyon17 data. Since we require different train, validation and test splits, you need to use our fork of the wilds package. Clone it, then run the training script with the following parameters

  > python examples/run_expt.py --dataset camelyon17 --root_dir /path/to/data \
      --split_scheme vanilla --seed 9