example.yaml

---
imports:
  - $import glob
  - $import matplotlib.pyplot as plt

# download and extract dataset (60MB):
url: "https://github.com/Project-MONAI/MONAI-extra-test-data/releases/download/0.8.1/MedNIST.tar.gz"
downloading: "$monai.apps.utils.download_and_extract(@url, './mednist.tar.gz')"

# construct the input paired data (moving and fixed images)
dataset_dir: "MedNIST/Hand"
datalist: $list(sorted(glob.glob(@dataset_dir + '/*.jpeg')))
paired_dataset: "$[{'f_img': item, 'm_img': item} for item in @datalist]"

# define preprocessing (additional randomization on the moving image)
preprocessing:
  _target_: Compose
  transforms:

    - _target_: LoadImaged
      keys: [f_img, m_img]
      image_only: True

    - _target_: EnsureChannelFirstd
      keys: [f_img, m_img]

    - _target_: ScaleIntensityRanged
      keys: [f_img, m_img]
      a_min: 0.
      a_max: 255.
      b_min: 0.0
      b_max: 1.0

    - _target_: RandRotated
      keys: [m_img]
      range_x: $np.pi/4
      prob: 1.0
      mode: "bicubic"
      keep_size: True

    - _target_: RandZoomd
      keys: [m_img]
      min_zoom: 0.9
      max_zoom: 1.1
      prob: 1.0
      mode: "bicubic"

# display the first pair of moving and fixed images
first_pair: $@preprocessing(@paired_dataset[0])
display:
  - _requires_: "@downloading"
  - $print("displaying images:")
  - $plt.subplot(1,2,1)
  - $plt.imshow(@first_pair['f_img'][0], cmap="gray")
  - $plt.subplot(1,2,2)
  - $plt.imshow(@first_pair['m_img'][0], cmap="gray")
  - $plt.show()