A function that transforms color RGB image to the grayscale image using the three popular methods

Img_transformer.py

def transf_RBG(image_arr, RBG_conv_met):
  """
  Takes an image array and a conversion method as inputs
  Transforms the color image to grayscale based on the specified method 
  """
  import cv2
  blue, green, red = cv2.split(image_arr)
  if RBG_conv_met == "Average":
    grayscale_im = (np.round(3**-1*blue + 3**-1*green + 3**-1*red)).astype('uint8')
    return grayscale_im
  elif RBG_conv_met == "Weighted_average":
    grayscale_im = (np.round(0.299*red + 0.587*green + 0.114*blue)).astype('uint8')
    return grayscale_im
  else:
    grayscale_im = (np.round(0.21*red + 0.72*green + 0.07*blue)).astype('uint8')
    return grayscale_im