def __pixelVelocity(self):
        ts = self
        if len(ts) < 2:
            return (0,0)
        dx = ts[-1].x - ts[-2].x
        dy = ts[-1].y - ts[-2].y
        return (dx, dy)
Send a message to the parent process to be handled by a registered handler.
dataset/ETHPy150Open sightmachine/SimpleCV/SimpleCV/Tracking/TrackSet.py/TrackSet.__pixelVelocity--crossover with--dataset/ETHPy150Open manahl/mdf/mdf/remote/messaging.py/send_message