import cv2


def find_corner_circles(im, area=(5000 / 4, 5000 * 4), color=None, convexity=0.9, circularity=0.7, inertia=None, thresholdstep=1):
    assert color is None and inertia is None, "Inertia and color not implemented (easy to do though)"
    params = cv2.SimpleBlobDetector_Params()

    params.filterByArea = area is not None
    if area is not None:
        params.minArea, params.maxArea = area

    params.filterByColor = color is not None
    params.filterByInertia = inertia is not None

    # This step should be lower than 10, preferrably as low as time allows, to avoud false negatives.
    params.thresholdStep = thresholdstep

    params.filterByCircularity = circularity is not None
    if circularity is not None:
        params.minCircularity = circularity
     
    params.filterByConvexity = convexity is not None
    if convexity is not None:
        params.minConvexity = convexity

    if int((cv2.__version__).split('.')[0]) < 3 :
        detector = cv2.SimpleBlobDetector(params)
    else:
        detector = cv2.SimpleBlobDetector_create(params)

    return detector.detect(im)