How wide is it?
If the width doesn't exceed the full height of your table saw blade (X2) you can saw/resaw it along the edge and flip one piece over and glue it back together.
This should take the curve out of it. A bandsaw would be better since the blade is thinner.
I'm not certain from the photo if the curve is in the edge or in the surface. a curved edge is easier to straighten than a curved surface... that's the issue I am suggesting above.
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)