Flow Matching for Medical Image Synthesis: Bridging the Gap Between Speed and Quality

To install the required packages, run:

pip install -r requirements.txt

Important Note:

• Your training data must be stored in a single .pkl file, which itself must follow the structure below.

Within that .pkl file, your data dictionary should look like:

{
  "train": [  # List of training samples
    {
      "image": "Tensor[Channels, Height, Width, ...] (float32, normalized)",
      "mask":  "Tensor[1, Height, Width, ...] (int32)",
      "class": "Scalar integer (int32)",
      "metadata": "Structured data (dict or other format)"
    },
    ...
  ],

  "valid": [  # List of validation samples
    {
      "image": "Tensor[Channels, Height, Width, ...] (float32, normalized)",
      "mask":  "Tensor[1, Height, Width, ...] (int32)",
      "class": "Scalar integer (int32)",
      "metadata": "Structured data (dict or other format)"
    },
    ...
  ],

  "test": [  # List of test samples
    {
      "image": "Tensor[Channels, Height, Width, ...] (float32, normalized)",
      "mask":  "Tensor[1, Height, Width, ...] (int32)",
      "class": "Scalar integer (int32)",
      "metadata": "Structured data (dict or other format)"
    },
    ...
  ]
}

Make sure your dataset adheres to the described data structure, saved in a single .pkl file, before running the training or inference pipelines.

You must either create or modify a YAML configuration file to suit your dataset paths, model parameters, and hyperparameters. Some sample configuration files are provided in the configs/ folder. By default, configs/default.yaml is used if no custom path is provided.

To train the model, run:

python trainer.py --config_path configs/default.yaml

• --config_path: Path to your YAML configuration file. Defaults to configs/default.yaml if not provided.

Note: Make sure you have prepared your dataset (as a single .pkl file) and configuration file properly before starting training.

To run inference with a trained model, use:

python inferer.py \
    --config_path configs/default.yaml \
    --num_samples 2000 \
    --model_path mask_class_conditioning_checkpoints/latest \
    --num_inference_steps 5

Below are explanations of the arguments:

• --config_path (str): Path to the configuration file. Defaults to configs/default.yaml.
• --num_samples (int): Number of samples to save. If you set it to None, all samples are saved. Defaults to 2000.
• --model_path (str): Path to the model checkpoint to load. Defaults to mask_class_conditioning_checkpoints/latest.
• --num_inference_steps (int): Number of inference steps during sampling. Defaults to 5.

Note: After inference, the script saves a .pkl file containing all generated samples in the same checkpoint folder (i.e., mask_class_conditioning_checkpoints/latest by default).

• 09.04.2025 | Code is released!
• 29.03.2025 | The paper is now available on Arxiv! 🥳

If you find this code or our work useful in your research, please cite:

@article{yazdani2025flow,
  title={Flow Matching for Medical Image Synthesis: Bridging the Gap Between Speed and Quality},
  author={Yazdani, Milad and Medghalchi, Yasamin and Ashrafian, Pooria and Hacihaliloglu, Ilker and Shahriari, Dena},
  journal={arXiv preprint arXiv:2503.00266},
  year={2025}
}

Enjoy working with MOTFM! Feel free to open an issue or pull request if you have any questions or suggestions.