Algorithm 3. Fragment of the Python code: function findContours().

# find countours in the mask

ctns = cv2.findContours(mask.copy(), cv2.RETR_EXTERNAL

# find the largest contour in the mask, then use

# it to compute the minimum enclosing circ

c = max(cnts, key = cv2.contourArea)

((x, y), radius) = cv2.minEnclosingCircle(c)