Abstract: A projection display uses a matrix of digital correction factors defining deflection correction factors between which linear interpolation is used for intermediate points on the display. A circuit for generating a correction signal to correct image distortion on a display screen, comprises a memory storing displacement values corresponding to spaced points on the screen in a grid of rows and columns. The displacement values of the grid generally define correction curves for correcting the image distortion without introducing significant banded regions on the display screen. An interpolator is coupled to the memory for interpolating intermediate values between adjacent ones of the stored displacement values, and a digital to analog converter is coupled to the interpolator for providing the correction signal.