src data type = 17 is not supported

TypeError Traceback (most recent call last)
in ()
1 t1 = time.time()
----> 2 o1 = process_image(path, 0, type='rect')
3 #cv2.imwrite('%s-detected.png' % path[:path.rfind('.')], o1)
4
5 print ('Time taken: %d ms'%((time.time()-t1)*1000))

in process_image(name, debug, **options)
7 raw_image = cv2.imread(name,1)
8 input_image = np.copy(raw_image)
----> 9 gray = cv2.cvtColor(input_image, cv2.COLOR_BGR2GRAY)
10 gray = enhance(gray)
11 gray = cv2.GaussianBlur(gray, (5,5), 0)

I am working to extract name plate using this code using 1-detection.png image but getting this error .
please verify and send the results