A method for automatic keystone correction in a projection system is provided that includes rectifying a first image to be projected using current keystone correction parameters to generate a first rectified image, projecting, by a projector in the projection system, the first rectified image on a projection surface, determining whether or not current keystone correction parameters are providing sufficient keystone correction after the first rectified image is projected, rectifying a second image to be projected using the current keystone correction parameters to generate a second rectified image if the current keystone correction parameters are providing sufficient keystone correction, computing new keystone correction parameters if the current keystone correction parameters are not providing sufficient keystone correction and rectifying the second image to be projected using the new keystone correction parameters to generate the second rectified image, and projecting, by the projector, the second rectified image on the projection surface.