import cv2

img = cv2.imread('../images/varese.jpg')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

surf = cv2.xfeatures2d.SURF_create(8000)
keypoints, descriptors = surf.detectAndCompute(gray, None)

cv2.drawKeypoints(img, keypoints, img, (51, 163, 236),
                  cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS)

cv2.imshow('surf_keypoints', img)
cv2.waitKey()