Rob writes: > If you can map the aberrations in a satellite > lens system while it is still on earth and make > a transform from it, you can actually use an > inverse transform to remove the aberrations. > The result is a sharper image than the camera > actually saw. No, it is just a _different_ image. You cannot create information that was not captured by the camera in the first place, but you can rearrange it so that it looks more useful to a human being. If you know the exact way in which light rays will be misdirected in a lens, you can redirect them through computer processing to arrive at an image that shows approximately what a perfect lens would have produced. However, if any aberrations or other defects caused a loss of information in the captured image, there is nothing you can do to restore that information. An area that is simply outside the plane of focus, for example, cannot be put into sharp focus by post processing. > It would be difficult to use on a commercial > basis due to the need to map the aberrations > of the lens system. It would be cheaper just to design and build a better lens. The military uses this method because they are already using the best lenses that can be made, and so the only way to do better is with a technique that is even more expensive than designing good lenses. But for ordinary photographic lenses, which generally do not push the limits of what is possible, it would be cheaper to just make the lens better than to spend money on extremely costly analysis and post-processing.