class_docstr: Image windows are retrieved and analysed by the
  tensorflow graph, this windows aggregator receives
  output window data in numpy array. To access image-level
  information the reader is needed.
class_docstr_tok: ["Image","windows","are","retrieved","and","analysed","by","the","tensorflow","graph",",","this","windows","aggregator","receives","output","window","data","in","numpy","array",".","To","access","image-level","information","the","reader","is","needed","."]
docstr: Index of the image in the output image list maintained by
  image reader.
  
  :return: integer of the position in image list
docstr_tok: ["Index","of","the","image","in","the","output","image","list","maintained","by","image","reader",".",":","return",":","integer","of","the","position","in","image","list"]
code: def image_id(self):
      """
      Index of the image in the output image list maintained by
      image reader.
  
      :return: integer of the position in image list
      """
      return self._image_id
  
file_path: NiftyNet/niftynet/engine/windows_aggregator_base.py
imports: from __future__ import absolute_import, print_function, division
  import os
  import numpy
  import tensorflow
  from niftynet.engine.image_window import N_SPATIAL
label_desc: Use image node_id 3 for calling the ImageWindowsAggregator obj's underlying member method code with example usage: obj.image_id() and returns: self