I have been using the HoughCircles function through Python for circle detection but wanted to speed it up by making use of Transparent API. I understand that usage of UMat is necessary for that and img is of such type

circles = cv2.HoughCircles(img,cv2.HOUGH_GRADIENT, 1.2, 1500)

When I run the code, I get this error:

hough.cpp:2254: error: (-215:Assertion failed) _circles.isMat() || _circles.isVector() in function 'HoughCircles'

I could find this assertion in here.

Even with giving circles (np.zeros((1,1,3), np.float32)) as an input parameter, it gives the same error. From my understanding this is something internal within the function and since I have little experience with openCV codebase, I wonder if this is a purposeful feature or a bug.