text: import operator
  
  boundaries = {  # fronts are more frequent here
      'min_x': 60,
      'max_x': 322,
      'min_y': 19,
      'max_y': 275,
  }
  
  
  def crop_center(img, bounding):
      start = tuple(map(lambda a, da: a // 2 - da // 2, img.shape, bounding))
      end = tuple(map(operator.add, start, bounding))
      slices = tuple(map(slice, start, end))
      return img[slices]
  
  
  def crop_boundaries(imgs):
      return imgs[:, boundaries['min_y']:boundaries['max_y'] + 1, boundaries['min_x']:boundaries['max_x'] + 1, :]
  
  
  def crop_2d(inp):
      return inp[boundaries['min_y']:boundaries['max_y'] + 1, boundaries['min_x']:boundaries['max_x'] + 1]
  