code: def get_gray_map(img):
      gray = cv2.cvtColor(img.astype(np.uint8), cv2.COLOR_BGR2GRAY)
      highPass = gray.astype(np.float32)
      highPass = highPass / 255.0
      highPass = 1 - highPass
      highPass = highPass[None]
      return highPass.transpose((1, 2, 0))
  
imports: import numpy
  import cv2
  from scipy import ndimage
label_desc: Use image node_id 2 for calling a global function with example usage: get_gray_map(img) and returns: highPass