TypeError: no matching UMat constructor found/supported

edit savecancel

When I use cv2.UMat,an error has occured,how can I fix it?

I have installed CUDA.

My test code:

import cv2

print(cv2.ocl.haveOpenCL())#True
cv2.ocl.setUseOpenCL(True)
print(cv2.ocl.useOpenCL())#True
pic1 = r'dog.jpg'
img = cv2.imread(cv2.UMat(pic1))
cv2.imshow('test',img)
cv2.waitKey(0)