| Author | Message | ||
     James Brady (Sinewave) New member Username: Sinewave Post Number: 8 Registered: 2-2009 Rating: N/A |
Hello everyone! I'm currently in the process of building my own wide FOV HMD, and I need a little advice. I was recently lucky enough to buy some LEEP optics taken from a FakeSpace boom3c for a very good price (it's been a bit of a dream of mine for a long time to get my hands on these), but one problem I've run into is getting LCD panels to fit together. These eyepieces are connected together rather closely, and it looks like I'm either going to have to find smaller LCDs of a decent resolution, or separate the eyepieces and tilt them slightly away from each other in order to allow for a bit more room in-between for the somewhat large LCD panels(3 inchs or so), sort of like LEEP Systems did with the Cyberface 2 HMD. Do you think that would work? or is there anything else I can do. If I have to seperate them, can someone suggest a good way to cut through the hard plastic shell without damaging the lenses inside? Here's a picture of them just in case you wanted to see what they looked like:http://dl.dropbox.com/u/665411/Cool%20Stuff/Virtual%20Reality/Leep%20Optics/DSC_0287%20-%20small.JPG Thanks! (Message edited by Sinewave on May 20, 2010) (Message edited by Sinewave on May 20, 2010) | ||
| Philipp B (Sinsilla) New member Username: Sinsilla Post Number: 6 Registered: 3-2010 Rating: N/A |
 Congratulations on the Leep Optics!! I tried to get me some too, but wasn´t lucky. I would really try to keep them as much in their original shape as possible. But that would probably limit you to 3,5" VGA Displays, 4" displays with a decent resolution are hard to find. If you would change the angle of the optics slightly you could probably go for 4,8" displays (WVGA/WSVGA), anything larger as this will be a problem. But since you got hold of LEEP Optics, you should always consider spending a little fortune on some 3,5" sxga or better. I wish you good luck and a lot of fun with this project! And if you get tired of the optics, i could help you out.  (Message edited by SinSilla on May 20, 2010) | ||
| James Brady (Sinewave) New member Username: Sinewave Post Number: 9 Registered: 2-2009 Rating: N/A |
Thanks! yeah, I'd really rather keep them in their original shape, it seems my biggest problem now is finding a place to actually buy the LCD modules around that size, especially with a decent resolution, not to mention it seems most of the ones I was able to find were only widescreen, they would need to be as even in hight and width as possible, so something with a 4:3 aspect ratio. I was considering ripping the LCD's from two projectors, but that would be a big pain, not to mention likely a lot more expensive. I also found a service that actually cuts/resizes LCD screens, so I might consider having them size down some widescreen panels if worse comes to worse, but I don't know how much that would cost. If anyone can let me know where I can buy some LCD's around the right size I'd really appreciate it. EDIT: I did some further testing, and it seems that I need exactly a 3.0 inch diagonal display for them to work correctly (not counting any frame there might be surrounding the LCD screen) (Message edited by Sinewave on May 21, 2010) (Message edited by Sinewave on May 21, 2010) (Message edited by Sinewave on May 21, 2010) | ||
| James Brady (Sinewave) New member Username: Sinewave Post Number: 10 Registered: 2-2009 Rating: N/A |
Sorry to double post, but I overlooked something big while testing these (duh), the image for LEEP optics is meant to be pre-distorted in a fisheye-like shape, I tested one of these images with the optics and it works perfectly, filling the full FOV. This means that I CAN use larger 4.5" LCD displays, I just have to write a custom fullscreen shader for my 3d apps to distort the image correctly. Sadly, LEEP optics don't seem to be good for conventional gaming, BUT my main reason for wanting them was to write a 3d app around them that fully supports the 6dof head tracker I'm going to use anyway. This makes things a bit more complicated, but more understandable, it also seems like it will be easier to get a good resolution for LCD's in this size. Here's an example of what the image has to look like: http://dl.dropbox.com/u/665411/Cool%20Stuff/Virtual%20Reality/Leep%20Optics/LeepTest2.jpg (Message edited by Sinewave on May 21, 2010) (Message edited by Sinewave on May 21, 2010) | ||
| Philipp B (Sinsilla) New member Username: Sinsilla Post Number: 8 Registered: 3-2010 Rating: N/A |
First shop that comes to mind would be Vitrolight. http://stores.ebay.com/VitroLight-LCD-Module-Bay He has almost every display available that you would find via google. You should contact him directly and ask for a display that would suit your needs. He may can help you out. Can you explain a little further what kind of 3D App you are going to make? Scientific stuff, entertainment? (Message edited by SinSilla on May 21, 2010) | ||
| James Brady (Sinewave) New member Username: Sinewave Post Number: 11 Registered: 2-2009 Rating: N/A |
Oh yeah, I've heard of Vitrolight, I actually just found that store recently, he seems to have a very good selection, I'll have to ask him if he has anything that isn't widescreen. My friend and I are actually working on two big indie game projects, and one smaller one on the side. one is an adventure/art game hybrid where you explore a large, surreal world, encountering strange characters as you go. The smaller project is a accurate recreation of the classic VR arcade game Dactyl Nightmare (minus the poor frame rate). Both of these projects will be open source, and playable with a standard mouse and keyboard, but I also want to make them as compatible as possible with various pieces of VR equipment. The other big project doesn't have anything to do with VR. | ||
| Tony Asch (Tone) Junior Member Username: Tone Post Number: 40 Registered: 8-2006 Rating: N/A |
Most LEEP based stereoscopic optical systems require LCDs which, when butted side-by-side have their centers wider than normal human eye spacing (interpupilary distance.) There are two solutions used by manufacturers of LEEP based systems: 1.) Prisms to bring the wide spaced images back into alignment. AFAIK everyone uses 3M Press-On fresnel prisms. 2.) Generate stereoscopic images which do not completely overlap horizontally. Thus, if your optical system has an IPD that is 25% wider than normal for humans, you would need to generate images where the left image only overlaps the right image with the rightmost 75% of that left image, and visa-versa for the right image. You'd only see stereoscopically in the central 75% of your vision. Actually, this is how we see the world anyway, since your nose blocks the left side of your right eye, and right side of your left eye. Hope this helps. VRtifacts.com | ||
| James Brady (Sinewave) New member Username: Sinewave Post Number: 12 Registered: 2-2009 Rating: N/A |
Thanks a lot for the info Tone! I'd prefer to have something that would be as compatible as possible with any program that supports 3d stereo, so the prisms are sounding good. That site that you linked me to seems to only sell to doctors, or people with prescriptions, I did find a site that looks like they'll sell them to anyone though (http://www.west-op.com/pressonprism.html). I take it I would want the 1 Diopter prisms? | ||
| Tony Asch (Tone) Member Username: Tone Post Number: 41 Registered: 8-2006 Rating: N/A |
For prisms one diopter shifts an image one unit for each 100 units of distance. So... for a screen that is 100mm away, a one diopter prism will horizontally shift the image 1mm. You should do the math on your own system. You'll probably wind up with 20 or 30 diopters. Parenthetically, I've seen several LEEP systems where the Press-On prisms were applied on the diagonal, allowing the displays to be offset vertically up or down. Obviously the horizontal diopter shift will be reduced by the cosine of the prism rotation angle. Finally, to eliminate key-stoning, you'll want to turn the displays slightly inward so that the line from the center of each lens to the center of the corresponding display forms a right angle with the display surface. VRtifacts.com | ||
| James Brady (Sinewave) New member Username: Sinewave Post Number: 13 Registered: 2-2009 Rating: N/A |
I see ,sorry for sounding so out of it, I'll definitely look into this more. Thanks again for the info, it looks like these will solve a lot of my problems. | ||
| Tony Asch (Tone) Member Username: Tone Post Number: 42 Registered: 8-2006 Rating: N/A |
You're not out of it... LEEPs haven't been in the mainstream for almost 20 years. The whole HMD industry veered off toward small (narrow FOV), ultralight displays and optics. BTW, I'll have an upcoming article on VR-tifacts showing how to build a LEEP-like optic out of inexpensive off-the-shelf lenses. VRtifacts.com | ||
| James Brady (Sinewave) New member Username: Sinewave Post Number: 14 Registered: 2-2009 Rating: N/A |
That's very cool, I've always been very interested in this subject so I look forward to reading that! I'm a big fan of your blog. | ||
| Philipp B (Sinsilla) New member Username: Sinsilla Post Number: 9 Registered: 3-2010 Rating: N/A |
Let me dito that! That sounds more than interesting. After trying out a lot of different lenses i ended up with a monoscopic design because i didn't get the results i was looking for. | ||
| James Brady (Sinewave) New member Username: Sinewave Post Number: 15 Registered: 2-2009 Rating: N/A |
I'm documenting every step that I take in making this HMD, so once I finally get everything working, I'm going to post a detailed guide with photos on how to make your own, this combined with the article Tone is writing should allow anyone to make one, provided they have the patience. | ||
| Ku (Kudawg) New member Username: Kudawg Post Number: 6 Registered: 9-2006 Rating: N/A |
Godd stuff guy's VERY interesting that the Virtual Reality Ball is still rolling. I thought it deflated years ago.. | ||
| Raz Fairlight (Sinewave) New member Username: Sinewave Post Number: 16 Registered: 2-2009 Rating: N/A |
Ok, just a small update, those fresnel prisms didn't really work out due to the fact that they make the image look pretty bad (they create a lot of blurring in the corner of your eyes), but on the bright side, I found some NTSC to VGA converter boxes that allow you to offset the image freely, allowing me to set up the overlap properly. I also won that auction for the Virtual Research Flight Helmet that popped up on ebay! so I'm going to open that up once I get it and use it as a bit of a reference for the inner layout of my HMD. PS. I'm also going to do a video at some point of the inner workings of the Flight Helmet, inspired by the tear-down videos that Tone made, so expect that within the next couple of weeks or so. EDIT: I almost forgot to ask, has anyone tried the SpacePoint Fusion tracker? it looks amazingly good for being a full 6DOF tracker at only $99 bucks: http://www.pnicorp.com/products/all/spacepoint-fusion (Message edited by Sinewave on June 03, 2010) (Message edited by Sinewave on June 04, 2010) | ||
| Joe Dunfee (Cadcoke4) New member Username: Cadcoke4 Post Number: 3 Registered: 3-2008 Rating: N/A |
First, let me apologize for just dumping some brainstorm ideas onto your thread. I know you are probably much further along in design concepts than what my idea is. Now that projectors are so small and lightweight they may be a viable way to do a large field of view in a HMD. People doing planetarium displays have been playing with aiming normal video projectors onto a spherical mirror. The focus of the projector has some blurring towards the perimeter. I wonder how the laser projectors fair in this setting? The have no focusing lens because they don't need one. But, after the image hits a spherical mirror, it will cause the beam to spread. Still, with a 1:1 ratio (6" away, will give an image 6" wide), the spherical mirror might be avoided if the geometry allows. The setup I am picturing involves two of the PicoP Laser projectors, aimed at two spheres that might make the wearer look like they have the eyes of a fly. This is to allow the projectors space to do two separate images. Since the "fly eyes" must be separated, the wearer would need to have mirrors in front of the eyes. Here are some links to some of the items I am talking about; PicoP Laser Projector; http://www.microvision.com/showwx/specs.html Projecting onto a sphere; http://local.wasp.uwa.edu.au/~pbourke/papers/graphite2005/graphite.pdf Note that this guy is the guru of this subject. His home page; http://local.wasp.uwa.edu.au/~pbourke/papers/ Joe Dunfee | ||
| Raz Fairlight (Sinewave) New member Username: Sinewave Post Number: 17 Registered: 2-2009 Rating: N/A |
Thanks for your ideas (the more the better)! I was actually planning to try something like that with mini projectors before I moved to this HMD project (which has sucked away a lot of my free time and extra cash), but I would still like to try this out one day. if you or anyone else tries this, be sure to post about it, I'm quite curious what could be done, because I think that technology is at a point now where a wide FOV HMD could be made at an affordable price. |
