'**SUMMARY**
Get Pixel Velocity of the tracked object in pixel/frame.
**PARAMETERS**
No Parameters required.
**RETURNS**
* *tuple* * - (Velocity of x, Velocity of y)'

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)
