.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_examples/self-supervised-learning/demo_equivariant_imaging.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        New to DeepInverse? Get started with the basics with the
        :ref:`5 minute quickstart tutorial <sphx_glr_auto_examples_basics_demo_quickstart.py>`.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_self-supervised-learning_demo_equivariant_imaging.py:


Self-supervised learning with Equivariant Imaging for MRI.
====================================================================================================

This example shows you how to train a reconstruction network for an MRI inverse problem on a fully self-supervised way, i.e., using measurement data only.

The equivariant imaging loss is presented in :footcite:t:`chen2021equivariant`.

.. GENERATED FROM PYTHON SOURCE LINES 10-22

.. code-block:: Python


    from pathlib import Path
    import torch
    from torch.utils.data import DataLoader
    from torchvision import transforms

    import deepinv as dinv
    from deepinv.datasets import SimpleFastMRISliceDataset
    from deepinv.utils import get_data_home, load_degradation
    from deepinv.models.utils import get_weights_url
    from deepinv.models import MoDL








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Setup paths for data loading and results.
---------------------------------------------------------------


.. GENERATED FROM PYTHON SOURCE LINES 26-36

.. code-block:: Python


    BASE_DIR = Path(".")
    DATA_DIR = BASE_DIR / "measurements"
    CKPT_DIR = BASE_DIR / "ckpts"

    # Set the global random seed from pytorch to ensure reproducibility of the example.
    torch.manual_seed(0)

    device = dinv.utils.get_freer_gpu() if torch.cuda.is_available() else "cpu"








.. GENERATED FROM PYTHON SOURCE LINES 37-56

Load base image datasets and degradation operators.
----------------------------------------------------------------------------------
In this example, we use a mini demo subset of the single-coil `FastMRI dataset <https://fastmri.org/>`_
as the base image dataset, consisting of 2 knee images of size 320x320.

.. seealso::

  Datasets :class:`deepinv.datasets.FastMRISliceDataset` :class:`deepinv.datasets.SimpleFastMRISliceDataset`
      We provide convenient datasets to easily load both raw and reconstructed FastMRI images.
      You can download more data on the `FastMRI site <https://fastmri.med.nyu.edu/>`_.

.. important::

   By using this dataset, you confirm that you have agreed to and signed the `FastMRI data use agreement <https://fastmri.med.nyu.edu/>`_.

.. note::

      We reduce to the size to 128x128 for faster training in the demo.


.. GENERATED FROM PYTHON SOURCE LINES 56-69

.. code-block:: Python


    operation = "MRI"
    img_size = 128

    transform = transforms.Compose([transforms.Resize(img_size)])

    train_dataset = SimpleFastMRISliceDataset(
        get_data_home(), transform=transform, train_percent=0.5, train=True, download=True
    )
    test_dataset = SimpleFastMRISliceDataset(
        get_data_home(), transform=transform, train_percent=0.5, train=False
    )








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Generate a dataset of knee images and load it.
----------------------------------------------------------------------------------



.. GENERATED FROM PYTHON SOURCE LINES 74-103

.. code-block:: Python


    mask = load_degradation("mri_mask_128x128.npy")

    # defined physics
    physics = dinv.physics.MRI(mask=mask, device=device)

    # Use parallel dataloader if using a GPU to speed up training,
    # otherwise, as all computes are on CPU, use synchronous data loading.
    num_workers = 4 if torch.cuda.is_available() else 0
    n_images_max = (
        900 if torch.cuda.is_available() else 5
    )  # number of images used for training

    my_dataset_name = "demo_equivariant_imaging"
    measurement_dir = DATA_DIR / "fastmri" / operation
    deepinv_datasets_path = dinv.datasets.generate_dataset(
        train_dataset=train_dataset,
        test_dataset=test_dataset,
        physics=physics,
        device=device,
        save_dir=measurement_dir,
        train_datapoints=n_images_max,
        num_workers=num_workers,
        dataset_filename=str(my_dataset_name),
    )

    train_dataset = dinv.datasets.HDF5Dataset(path=deepinv_datasets_path, train=True)
    test_dataset = dinv.datasets.HDF5Dataset(path=deepinv_datasets_path, train=False)





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    mri_mask_128x128.npy degradation downloaded in datasets
    Dataset has been saved at measurements/fastmri/MRI/demo_equivariant_imaging0.h5




.. GENERATED FROM PYTHON SOURCE LINES 104-112

Set up the reconstruction network
---------------------------------------------------------------

As a (static) reconstruction network, we use an unrolled network
(half-quadratic splitting) with a trainable denoising prior based on the
DnCNN architecture which was proposed in MoDL :footcite:t:`aggarwal2018modl`.
See :class:`deepinv.models.MoDL` for details.


.. GENERATED FROM PYTHON SOURCE LINES 112-116

.. code-block:: Python


    model = MoDL()









.. GENERATED FROM PYTHON SOURCE LINES 117-132

Set up the training parameters
--------------------------------------------
We choose a self-supervised training scheme with two losses: the measurement consistency loss (MC)
and the equivariant imaging loss (EI).
The EI loss requires a group of transformations to be defined. The forward model should not be equivariant to
these transformations :footcite:t:`tachella2023sensing`.
Here we use the group of 4 rotations of 90 degrees, as the accelerated MRI acquisition is
not equivariant to rotations (while it is equivariant to translations).

See :ref:`docs <transform>` for full list of available transforms.

.. note::

      We use a pretrained model to reduce training time. You can get the same results by training from scratch
      for 150 epochs using a larger knee dataset of ~1000 images.

.. GENERATED FROM PYTHON SOURCE LINES 132-157

.. code-block:: Python


    epochs = 1  # choose training epochs
    learning_rate = 5e-4
    batch_size = 16 if torch.cuda.is_available() else 1

    # choose self-supervised training losses
    # generates 4 random rotations per image in the batch
    losses = [dinv.loss.MCLoss(), dinv.loss.EILoss(dinv.transform.Rotate(n_trans=4))]

    # choose optimizer and scheduler
    optimizer = torch.optim.Adam(model.parameters(), lr=learning_rate, weight_decay=1e-8)
    scheduler = torch.optim.lr_scheduler.StepLR(optimizer, step_size=int(epochs * 0.8) + 1)

    # start with a pretrained model to reduce training time
    file_name = "new_demo_ei_ckp_150_v3.pth"
    url = get_weights_url(model_name="demo", file_name=file_name)
    ckpt = torch.hub.load_state_dict_from_url(
        url,
        map_location=lambda storage, loc: storage,
        file_name=file_name,
    )
    # load a checkpoint to reduce training time
    model.load_state_dict(ckpt["state_dict"])
    optimizer.load_state_dict(ckpt["optimizer"])





.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    /home/runner/work/deepinv/deepinv/deepinv/transform/rotate.py:46: UserWarning: The default interpolation mode will be changed to bilinear interpolation in the near future. Please specify the interpolation mode explicitly if you plan to keep using nearest interpolation.
      warn(
    Downloading: "https://huggingface.co/deepinv/demo/resolve/main/new_demo_ei_ckp_150_v3.pth?download=true" to /home/runner/.cache/torch/hub/checkpoints/new_demo_ei_ckp_150_v3.pth

      0%|          | 0.00/2.17M [00:00<?, ?B/s]
    100%|██████████| 2.17M/2.17M [00:00<00:00, 29.6MB/s]




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Train the network
--------------------------------------------


.. GENERATED FROM PYTHON SOURCE LINES 161-191

.. code-block:: Python



    verbose = True  # print training information

    train_dataloader = DataLoader(
        train_dataset, batch_size=batch_size, num_workers=num_workers, shuffle=True
    )
    test_dataloader = DataLoader(
        test_dataset, batch_size=batch_size, num_workers=num_workers, shuffle=False
    )

    # Initialize the trainer
    trainer = dinv.Trainer(
        model,
        physics=physics,
        epochs=epochs,
        scheduler=scheduler,
        losses=losses,
        optimizer=optimizer,
        train_dataloader=train_dataloader,
        plot_images=True,
        device=device,
        save_path=str(CKPT_DIR / operation),
        verbose=verbose,
        show_progress_bar=False,  # disable progress bar for better vis in sphinx gallery.
        ckp_interval=10,
    )

    model = trainer.train()




.. image-sg:: /auto_examples/self-supervised-learning/images/sphx_glr_demo_equivariant_imaging_001.png
   :alt: Ground truth, Measurement, Reconstruction
   :srcset: /auto_examples/self-supervised-learning/images/sphx_glr_demo_equivariant_imaging_001.png
   :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    The model has 187019 trainable parameters
    Train epoch 0: MCLoss=0.0, EILoss=0.0, TotalLoss=0.0, PSNR=40.568




.. GENERATED FROM PYTHON SOURCE LINES 192-196

Test the network
--------------------------------------------



.. GENERATED FROM PYTHON SOURCE LINES 196-199

.. code-block:: Python


    trainer.test(test_dataloader)




.. image-sg:: /auto_examples/self-supervised-learning/images/sphx_glr_demo_equivariant_imaging_002.png
   :alt: Ground truth, Measurement, No learning, Reconstruction
   :srcset: /auto_examples/self-supervised-learning/images/sphx_glr_demo_equivariant_imaging_002.png
   :class: sphx-glr-single-img


.. rst-class:: sphx-glr-script-out

 .. code-block:: none

    Eval epoch 0: PSNR=37.439, PSNR no learning=32.749
    Test results:
    PSNR no learning: 32.749 +- 0.000
    PSNR: 37.439 +- 0.000

    {'PSNR no learning': 32.74856948852539, 'PSNR no learning_std': 0.0, 'PSNR': 37.43928527832031, 'PSNR_std': 0.0}



.. GENERATED FROM PYTHON SOURCE LINES 200-203

:References:

.. footbibliography::


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 12.291 seconds)


.. _sphx_glr_download_auto_examples_self-supervised-learning_demo_equivariant_imaging.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: demo_equivariant_imaging.ipynb <demo_equivariant_imaging.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: demo_equivariant_imaging.py <demo_equivariant_imaging.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: demo_equivariant_imaging.zip <demo_equivariant_imaging.zip>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_