code: def extractColor(self, frame):
      # r = np.mean(frame[:,:,0])
      g = np.mean(frame[:, :, 1])
      # b = np.mean(frame[:,:,2])
      # return r, g, b
      return g
  
file_path: heart-rate-measurement-camera/process.py
imports: import cv2
  import numpy
  import time
  from face_detection import FaceDetection
  from scipy import signal
  from face_utilities import Face_utilities
  from signal_processing import Signal_processing
  from imutils import face_utils
label_desc: Use image node_id 2 for calling the Process obj's underlying member method code with example usage: obj.extractColor(frame) and returns: g