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View Full Version : Interested in making a head mounted display?



Lurch1962
02-14-2008, 06:38 PM
I am!

Why? Existing lower-cost commercial displays are of low resolution, and furthermore are hindered by small fields of view. But more attractive units cost the Moon.

I'm only just now beginning to look into component costs. I've e-mailed one micro display manufacturer for the cost of their 1280x1024 color module and driver electronics. Here's a link to a 2-page PDF on this interesting device:

http://www.forthdd.com/SX-CS.pdf

The display's diagonal size is 22mm (0.88 inch), which is a nice size for a 13mm or 15mm focal length, 80 degree apparent field of view telescope ocular.

Compare this with existing lower-cost LCD glasses and HMDs having apparent fields of between 26 and 55 degrees. The 80 degree field is simply HUGE(!!) by comparison. For example, the area ratio for 55 and 80 degree fields is 2.1. In other words, I would have at least double the area of my retinas illuminated with imagery as compared to even the wider field commercial HMD's. The immersion factor would be quite significant.

To appreciate what an 80 degree field of view would look like, put your face at the appropriate distance from your monitor right now, according to the list below (interpolate if necessary):

Screen diagonal Distance (both are inches)
17................10.1
19................11.3
22................13.1
24................14.3
28................16.7
32................19.1
36................21.5
40................23.8

To calculate an 80 degree apparent field for your specific monitor, multiply the diagonal size by 0.6.

For a 4:3 aspect display, an 80 degree diagonal field would subtend 64 x 48 degrees, approximately. Therefore the game's FOV when set to about 65 degrees (the exact value depending on optical distortion) would appear at true-to-life size. (The default, or "normal" FOV in IL2 is 70 degrees.)

Even at the widest 90 degree FOV in-game, the scale difference would not be *too* great.

Coupled with a TrackIR calibrated so as to allow maximum range of motion of the player's head, the result would be near complete immersion! (A true 1:1 correspondence of player-to-virtual pilot movement is impossible because of the way the tracker works.)

In order to achieve the greatest visual impact, one could elect to use a slightly shorter focal length ocular if one is willing to clip the corners of the display. After all, what small amounts are lost can be easily be compensated for with a wee bit of head movement.

Of course, maximum retinal coverage would be obtained via an eyepiece whose circular field stop (which lies at the focal plane) just fully includes either the horizontal dimension or the shorter vertical dimension. The latter set-up would offer a circular field with maximum retinal coverage, but with significant clipping of the available field. Even for me that would be too much of a sacrifice.

--Lurch--

Lurch1962
02-14-2008, 06:38 PM
I am!

Why? Existing lower-cost commercial displays are of low resolution, and furthermore are hindered by small fields of view. But more attractive units cost the Moon.

I'm only just now beginning to look into component costs. I've e-mailed one micro display manufacturer for the cost of their 1280x1024 color module and driver electronics. Here's a link to a 2-page PDF on this interesting device:

http://www.forthdd.com/SX-CS.pdf

The display's diagonal size is 22mm (0.88 inch), which is a nice size for a 13mm or 15mm focal length, 80 degree apparent field of view telescope ocular.

Compare this with existing lower-cost LCD glasses and HMDs having apparent fields of between 26 and 55 degrees. The 80 degree field is simply HUGE(!!) by comparison. For example, the area ratio for 55 and 80 degree fields is 2.1. In other words, I would have at least double the area of my retinas illuminated with imagery as compared to even the wider field commercial HMD's. The immersion factor would be quite significant.

To appreciate what an 80 degree field of view would look like, put your face at the appropriate distance from your monitor right now, according to the list below (interpolate if necessary):

Screen diagonal Distance (both are inches)
17................10.1
19................11.3
22................13.1
24................14.3
28................16.7
32................19.1
36................21.5
40................23.8

To calculate an 80 degree apparent field for your specific monitor, multiply the diagonal size by 0.6.

For a 4:3 aspect display, an 80 degree diagonal field would subtend 64 x 48 degrees, approximately. Therefore the game's FOV when set to about 65 degrees (the exact value depending on optical distortion) would appear at true-to-life size. (The default, or "normal" FOV in IL2 is 70 degrees.)

Even at the widest 90 degree FOV in-game, the scale difference would not be *too* great.

Coupled with a TrackIR calibrated so as to allow maximum range of motion of the player's head, the result would be near complete immersion! (A true 1:1 correspondence of player-to-virtual pilot movement is impossible because of the way the tracker works.)

In order to achieve the greatest visual impact, one could elect to use a slightly shorter focal length ocular if one is willing to clip the corners of the display. After all, what small amounts are lost can be easily be compensated for with a wee bit of head movement.

Of course, maximum retinal coverage would be obtained via an eyepiece whose circular field stop (which lies at the focal plane) just fully includes either the horizontal dimension or the shorter vertical dimension. The latter set-up would offer a circular field with maximum retinal coverage, but with significant clipping of the available field. Even for me that would be too much of a sacrifice.

--Lurch--

stalkervision
02-14-2008, 08:18 PM
http://www.youtube.com/watch?v=Jd3-eiid-Uw

Probably not what you wanted but interesting to watch.. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Zoom2136
02-15-2008, 08:26 AM
Check out the VR920 or AV920 VR HMD

These are 640 x 480 but scale up to 1024 x 768...

They include head tracking, a mic, and earpeace...

They are said to show the equivalent of a 24" screen at a 12" viewing distance...

all this for 350 to 400$

Lurch1962
02-18-2008, 08:40 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">They are said to show the equivalent of a 24" screen at a 12" viewing distance... </div></BLOCKQUOTE>

I doubt it. That would correspond to a 90 degree (!!) field. The web site states a 32 degree field, which corresponds to a 24" screen seen from 42". http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Stalker,
Thanks for the youtube link, as it was interesting! (And well presented.)

joe.08
02-18-2008, 10:13 PM
did you get a price (on the display).

do you know what kind of optics you would use?

Lurch1962
02-24-2008, 02:20 PM
Got a reply from the micro display manufacturer. The development kit costs $7950 (!!). Guess I'll be sticking to my good ol' 19" CRT running at 1600x1200 for the time being. If I won the lottery, however... http://forums.ubi.com/images/smilies/784.gif