cv2.imshow("output", frame) def getMiddle(x, y): return ((x[0] + y[0]) / 2, (x[1] + y[1]) / 2) mx = [] my = [] if __name__ == '__main__': cv2.namedWindow('output') cv2.setMouseCallback('output', clickHandler) port = Port() port.init() lasttimeSent = None prevRobot = [None] * N prevWhite = [None] * N vc = cv2.VideoCapture(1) balls = None rval, frame = vc.read() while rval: rval, frame = vc.read() robots = [None] * N whites = [None] * N