1. A projector, comprising: an image projector to project an image; a set of inherent parameters including a horizontal resolution Wn 0 , a vertical resolution Hn 0 , a depth d, and a vertical offset db; a receiver to receive a vertical tilt angle βv, and the horizontal tilt angle βh; and a corrector which computes keystone correction corner points for the image using the set of inherent parameters, the vertical tilt angle βv, and the horizontal tilt angle βh, and corrects the image internally to the projector.