Question about collimated display systems.

[presse55]

Hello

I'm glad I found this thread. I find this topic fascinating and am working to improve my understanding of the optics involved.

Following wlzedian's earlier post (ex. #58 ), I developed an excel spreadsheet to calculate points on a surface screen for a hypothetical collimated display. Using the resultant points, I am able to develop a very close fitting ellipsoid (major axis is horizontal, center is same as mirror, rotation axis is vertical also through center of sphere).

What I get are parameters (a,b) for the ellipse as shown here

http://www.flickr.com/photos/alfredetlaura/6032314024/

What puzzles me now is:
From the (pilot's) eyepoint, how much vertical and horizontal movement still provides an image reasonably free of distortion? In other words, how can I assess what I will see as my head moves from sided to side, or up and down? Any distortion?


Mike.Powell writes (post #78 ) something I do not understand:
"Once you have a workable configuration, you can ray trace diverging paths from multiple points on the screen surface to check for collimation accuracy."

I'm not sure how to go about doing this 'in 3D'. I can hardly immagine doing these calculations manually. I am under the impression that to answer this question, 3D ray tracing is probably required, but I'm at a loss as to how to go about doing this. I am not familiar with TurboCad.

Any pointers are well appreciated!

Ron,


On a side note:
In astronomical telescope design, a similar problem arises with the so-called tilted component scopes, such as the Schiefspiegler; with these scopes, there are two spheric reflecting surfaces tilted with respect to one another. In telescope design in general, ray traces and spot diagrams are done for two perpendicular planes: the tangential and the sagittal planes. This is well explained in Telescope Optics - Evaluation & Design, Rutten & Venrooij, Wilmann-Bell, 1988.

I'm left wondering if methods used in evaluating tilted component telescope design can be used in collimated displays.

[beermonster]

Well as a person that didn't know anything about collimated display systems until yesterday let me say I'm all excited and the Mrs has given me the go ahead to build one, so long as it's a two person set-up. Here are a few dumb questions and cross referencing from different industries.

1) Does the mirror have to be 100% reflective? Of course you want the best you can afford; but where is the middle ground? My first projector used a white wall and then a bed sheet, so I can accept a lot of imperfections along the way.
I've been following this guy who tries a lot of diy mirror configurations for solar power and he as made a few nice looking easy(ish) to make parabolic mirrors. As we only want a portion of the mirror it looks feasible. http://www.youtube.com/watch?v=St-0HWKAY4k
http://www.youtube.com/watch?v=MYC7HyKbkpI

1b) As they do with telescope mirrors . If you attached a lot of control points on the back of a steel mirror could you pull it into the shape you wanted and correct and fine tune the image digitally. I've been looking at a lot of Johnny Chung Lee work and this could be set up to auto correct the image you want to see. http://johnnylee.net/projects/thesis/

Getting rid of the huge mirror idea. I understand why don't you project on to a white screen as it helps the illusion to bounce one image off another S0 -
2) It is possible to use a projector to project on to a mirror and have that image bounce of a white background into the eye? I just thought you could inflate a mylar balloon easier. I guess the balloon could be over sized and the holding frame would make the mylar bulge and deform where needed. You could even inflate the ballon to full a much easier to make acrylic former.

Just my ideas. Are there any CAD plans for building this. I haven't understood the maths to make one yet.

I've also though about using corian as a surface to project on to OR apply a mirror finish to.

Thanks for a good weekend of reading.

[Papa#1]

Hello,
Im very new to everything. I guess you can call me a (newbe). I need help on getting my game to work. I have eyefinity six video card and tryinbg to run six monitors. If can give any advise please let me know.

Thanks!!!
Papa#1

[jackwall]

Papa #1 ....

A couple of google search links to start you off ....

http://www.tomshardware.com/forum/27...heck-eyefinity

http://www.devhardware.com/forums/at...ty-310385.html

http://forums.whirlpool.net.au/archive/1469262

There is a load more on the web and I recommend some surfing and reading ......

It's kinda difficult to help when the problem is such a broad one. Exactly what problems have you encountered so far. Like, do you need help with physical installation or with configuration after your physically connected in the new card.

Try being a little more specific in the help you need and typcially someone on here will offer.

Also, this is a thread that is about Collimated Displays so it may be appropriate to start your own thread for your question !!!

Good luck
rgds

[Papa#1]

Thank you for the message. I will see if any of these may be helpful to work with. My can turn on the game just fine. It will let me up until the point I go to fly. Then the screens all go black then start flasking. The game will then shut itself down. I can't figure out why? Any suggestions?

Papa #1 ....

A couple of google search links to start you off ....

http://www.tomshardware.com/forum/27...heck-eyefinity

http://www.devhardware.com/forums/at...ty-310385.html

http://forums.whirlpool.net.au/archive/1469262

There is a load more on the web and I recommend some surfing and reading ......

It's kinda difficult to help when the problem is such a broad one. Exactly what problems have you encountered so far. Like, do you need help with physical installation or with configuration after your physically connected in the new card.

Try being a little more specific in the help you need and typcially someone on here will offer.

Also, this is a thread that is about Collimated Displays so it may be appropriate to start your own thread for your question !!!

Good luck
rgds

[Salire]

I've read this thread now about 3 times, and am totally fascinated. It's incredibly impressive and I'm seriously thinking about taking it on myself. But the thread died abruptly last year. Wayne and Gene, did you get done and now are having too much fun? Any updates? Lessons learned?

Thanks,

Salire

[geneb]

Salire, if you head over to http://www.youtube.com/f15sim, you can see the most recent videos that we've done on the project.

More exciting news will likely be posted this coming weekend.

g.

[Salire]

Thanks, Gene. Yes, I've seen all your videos, read your site, downloaded the patents, etc. The size of your rig looks doable for the space I have available (first time I've ever had a rumpus room and I want to take advantage of it). So before I start on something I'd sure love to be able to stand on your shoulders and learn from the experience.

I'm curious, too, about your personal assessment on the marginal benefit (in terms of immersive experience) of having the collimated view over a simpler wrap-around direct projection (dome or cylinder)?

Sal

[geneb]

The benefit of collimated vs a direct projected screen is HUGE. You get a sense of depth that simply isn't possible with a "normal" projected screen. The visual cues you get are as close as possible to reality - this is why the FAA mandates collimated displays for Full Flight Simulators.

Wayne can tell you much more about how he experiences the visuals than I can - I don't have binocular vision (my eyes don't work together, they work individually, so I have no "built-in" depth perception).

You should keep in mind that the display project we've built is really only suitable for a single seat cockpit - it's not large enough to do a proper two place cockpit, even a small one like a Cessna 152.

g.

[Salire]

Thanks.
re: Single seat: Yes, that's one reason I'm so attracted to the scale of your project. I'm planning a single seat GA configuration with a glass cockpit. The first try is going to be X-Plane with a FlyThisSim G1000 avionics emulation controlled by an ACER 24" touch screen, and the CH products HOTAS control suite. I'm basically going for state of the art high performance GA VLJ or Cirrus type design, but generic. I want a realistic flying experience, but I'm not driven to make it a replica of anything. In fact, I enjoy playing with the ergonomic design aspects. The OTW experience is a big deal to me, so I'm really wanting to do something that delivers. Sounds like the size of what you guys did is perfect for my application. Once I get the OTW display set, then I would build the cockpit accordingly to make the pilot view fit with the display limits.

S