docstr: :param initializer:  initializer used for sub kernels (orthogonal, glorot uniform, etc.)
  :param upsample_factor: upsample factor of sub pixel convolution
code: def __init__(self, initializer, upsample_factor=1):
      """
      :param initializer:  initializer used for sub kernels (orthogonal, glorot uniform, etc.)
      :param upsample_factor: upsample factor of sub pixel convolution
      """
      self.upsample_factor = upsample_factor
      self.initializer = initializer
  
file_path: NiftyNet/niftynet/layer/subpixel.py
imports: from __future__ import absolute_import, print_function
  import tensorflow
  from niftynet.layer.base_layer import TrainableLayer
  from niftynet.layer.convolution import ConvolutionalLayer
  from niftynet.layer.downsample import DownSampleLayer
label_desc: Use image node_id 1 to create a new _ICNR object  with example: obj = _ICNR(initializer, upsample_factor)