1. A method of operating a projection imaging system comprising a microdisplay, projection optics and a viewing screen having multiple optical surfaces, said method comprising: converting an input video signal to image generation commands and transmitting said image generation commands to the microdisplay, said image generation commands corresponding to a reference image; operating the microdisplay to accept the image generation commands output an image to the projection optics, including an image of the reference image; transmitting the image through the projection optics, including the image of the reference image, to an image plane to create a projected image corresponding to the reference image; capturing an image of the projected image from an intermediate optical surface and; comparing the reference image with the captured image, and generating a warping map based on that comparison, and thereafter pre-warping image generation commands according to the warping map so that the projected image is corrected for distortions in the system.