code: def monai_to_itk_ddf(image, ddf):
      """
      converting the dense displacement field from the MONAI space to the ITK
      Args:
          image: itk image of array shape 2D: (H, W) or 3D: (D, H, W)
          ddf: numpy array of shape 2D: (2, H, W) or 3D: (3, D, H, W)
      Returns:
          displacement_field: itk image of the corresponding displacement field
  
      """
      # 3, D, H, W -> D, H, W, 3
      ndim = image.ndim
      ddf = ddf.transpose(tuple(list(range(1, ndim + 1)) + [0]))
      # x, y, z -> z, x, y
      ddf = ddf[..., ::-1]
  
      # Correct for spacing
      spacing = np.asarray(image.GetSpacing(), dtype=np.float64)
      ddf *= np.array(spacing, ndmin=ndim + 1)
  
      # Correct for direction
      direction = np.asarray(image.GetDirection(), dtype=np.float64)
      ddf = np.einsum(
          "ij,...j->...i", direction, ddf, dtype=np.float64
      ).astype(np.float32)
  
      # initialise displacement field -
      vector_component_type = itk.F
      vector_pixel_type = itk.Vector[vector_component_type, ndim]
      displacement_field_type = itk.Image[vector_pixel_type, ndim]
      displacement_field = itk.GetImageFromArray(
          ddf, ttype=displacement_field_type
      )
  
      # Set image metadata
      displacement_field.SetSpacing(image.GetSpacing())
      displacement_field.SetOrigin(image.GetOrigin())
      displacement_field.SetDirection(image.GetDirection())
  
      return displacement_field
  
imports: from __future__ import annotations
  from typing import TYPE_CHECKING, cast
  import numpy
  import torch
  from monai.config.type_definitions import DtypeLike
  from monai.data import ITKReader, ITKWriter
  from monai.data.meta_tensor import MetaTensor
  from monai.data.utils import orientation_ras_lps
  from monai.transforms import EnsureChannelFirst
  from monai.utils import MetaKeys, SpaceKeys, convert_to_dst_type, optional_import
label_desc: Use image node_id 11 for calling a global function with example usage: monai_to_itk_ddf(image, ddf) and returns: displacement_field