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Re: Parts tips for making an EyeTap-like display

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On Fri, 6 Dec 2002  wrote:

> Well then...you mentioned that cost was the all important factor
> in this project.  Let me suggest an NTSC video camera viewfinder,

	I think I will do so - I happen to have a broken camcorder, but
the viewfinder seems to be working.

> You'll need to figure out some way to put the camera, virtually, 
> inside your eye.  Your suggestion of 2-way mirrors would work,

	Yeah, actually I'm just taking advantage of Professor Mann's
previous work on EyeTaps.  He's got the entire thing pretty well
documented - in the theory department, anyway.  It's tough to find any
specific building tips.  For example, in the Intelligent Image Processing
book he alludes to how one would make adjustments for lenses that are too
wide or too tele, but doesn't actually say how.

	I hoped I could tap someone on the list (someone who's got
experience making such a setup, I mean), but if not perhaps I'll
see if I can get any tips from him directly.

> Be aware, though, it will not track your eyeball...if this is your
> intention, it'll have to be a LOT more complicated.

	No, nothing about tracking the eye is in the plans.

> If you want to compensate for parallax, that's a relatively simple
> task, especially considering that the IR LASER could act as a
> rangefinder, and "dial in" the right amount of compensation.  )

	I'm not considering any such feedback/correction setup at this
stage.

> Now, as to camera lens.  I assume you mean focal length.

	No, I mean Field of View (FOV).

	I'm not going to be interested in anything closer than a few feet
away - certainly not in a test setup, anyway.  So the focal length of any
camera I use should be fine.  

	However, it is EXTREMELY important that the FOV of the camera
matches the physical "sub-FOV" of the display in my eyes' "real" FOV.

	In other words, if the HMD display is (for example) 10 degrees
wide in my field of view, the camera's FOV (displayed on that display) had
better _also_ be 10 degrees!  Otherwise, what would the point be?

	So, just to narrow things down...

- - Anyone have suggestions to altering a camera's FOV?  Either by different
lens (any considerations?  specific lens suggestions?) or by some other
trick?  Ideally, is there some way to _make_ a camera's otherwise fixed 
FOV adjustable? (I'm thinking these CMOS board cameras, here)

	I have the physical setup sorted out (ie parts layout required to
obtain the EyeTap condition).

Don Papp
http://AEinnovations.com

GNUPG/PGP Key: http://AEinnovations.com/downloads/pubkey.html

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