[simpits-tech] Visual system questions (Gene) and an idea

[dabigboy at cox.net]

Hey Gene, in my research on visual systems, I came across a common issue with curved/spherical screens and projectors. It has been noted that even when you use software to warp and edge-blend the projectors for a curved screen, areas further from the center of the screen go out of focus. From the videos of your system, it doesn't appear this is an issue, although I can't really tell for sure just from vids.....I would guess that the relatively minor curve of your front-projection screen keeps the focus issue to a minimum (another big advantage of your system's use of a spherical mirror as opposed to projecting directly onto a main screen), but I am curious: has this been an issue for you?

For folks projecting directly onto a curved screen, I have always thought that it would be better to use some sort of lens on the projector that would warp the image, as opposed to using software. I even saw one sim builder mention this on the X-Plane.org forums, he had a curved screen and mentioned just using a lens on the front of the projector to warp things properly...I asked him about it but never got a reply.

It appears that the lens I seek is a simple fisheye/wide-angle lens, and that planetariums actually use this concept for their projection systems. It makes a lot more sense to use natural optics for the angle correction, as opposed to taking away pixels from the image and trying to shove it into shape with software. Plus you wouldn't need to spend $500+ on warping software. :)

Similarly, for people with cylindrical screens, a cylindrical mirror could be used (I think?) whose angle is equal to the angle of the main screen.

Obviously such a lens for Gene's system would be a little more exotic, since the little front projection screen above the pilot complicates things a bit. I think you would need something that is like a fisheye lens in reverse.

Brainstorming. Fun.......now I need to find my card reader so I can upload pics of my Jeppesen/PFC yoke that I hackerized into my sim. :)

Matt