Hi all,

I wanted to share with you my work in progress on my diy hmd
The parts I used :

- Sharp 7.2" LCD LQ072K1LA03 with HDMI controller (WXGA 1280x768) -> it gives 640x720 resolution per eye
- 2 aspheric lenses from here

I don't know what is exactly the FOV but I think it is about 100° or more horizontally and full FOV vertically

here is a short video of it :



I still need to think about the system to hold the lenses (which has to be adjustable for IPD and for focus) and I will update this thread with new pictures and videos

Any remark or any question is welcome

Thanks for reading

Wow! That looks pretty impressive. Do you have plans to make a head-mount, or will this be a stationary unit?

Thank you cybereality
yes I definitely want it to be head mounted, it's already pretty immersive and I can't imagine how it will be when I will be able to display a virtual world with head tracking
I estimated it will weight < 900gr when it is finished.
I have no clue how I will attach it to my head (I mean comfortably) maybe with a motorcycle helmet (if I can find one)

Very cool! Your design is a lot like the one I have been using with a 5.6" panel.

A few questions:

1) How do your eyes converge on the image? It seems like the center of each half of the screen would be too wide.
2) How much of the image do the lenses cut off? How is distortion on the edges?

For a helmet, you will want to counterweight it by putting something on the back. I suggest trying a bicycle helmet, look for one with a ratcheting nape strap on the back.

Oh, and try comparing the size of the image to how large your normal monitor is. Move further away or closer to the monitor until the image width matches up, and tell us how far away from your monitor you are. Someone here should be able to do the math!

Are those the "LEEP on the cheap" diy optics ? If not, what optics are they ?

NEVER MIND, how did I miss that. Went right to your video too fast I guess.
So it is just one lens for each eye ?

@PalmerTech :

1)
Yes the centers of the two images are too far appart so I have to tilt a little bit the lenses like that


2)
The merged image looks approximately like that


I compared the image size with the one from my optoma projector and it seems to be same size if I stand at ~60cm from the projected image which is 2.70m wide. I did the math and it gives 132° horizontal FOV
(90° - atan(60/135)) * 2 = 132°

@3dvison :

Yes it is just one lens per eye
While reading a lot this forum I discovered that other people suggest aspheric lenses idea to make a LEEP-like optical system
from the article of this thread :



My lenses have a shorter focal length than the suggested one resulting in a wider FOV but maybe a bigger distortion

Wow, just tilting the lenses provides enough correction? Awesome!

Could you do a test for me? How wide/tall is the FOV when you view an image that is 8.6cm tall, and 6cm wide? I would really appreciate it, I might buy some lenses like this myself.

Thanks for your time and reply foisi.

I like your lens setup also. Seems we should be able to make somthing for the Wrap line of HMDs for a larger FOV ...?
One lens sounds easy..err..maybe ?

Hi,

@PalmerTech :
I measured the angle and it is (very) approximately 99° for 8.6cm and 89° for the 6cm.
I used a cardboard stuff to mount the lens at the focusing distance and a laser pointer :



I hope it helps

@3dvison :

I don't know if it is possible (you are talking about Vuzix wrap HMDs?)... I'm not good at optics but I don't think that it is possible to adapt these lenses

edit :

I did the test again and I found that I didn't point the laser beam to the exact center of the lens for the vertical FOV :


it's 123° and not 99°

horizontal FOV (for 6cm wide image) is still 89°


I also did the test for my 8cm wide images and it is in fact 110° per eye horizontal FOV (and not 132°)

Another awesome project. Can you give us a source for those lenses?

The link was in the OP:
http://www.fresnels.fr/achat/produit_de ... a782944cdd

Been awhile!!


Hows this project coming out?

Hello,

sorry I've been a little busy last months so it didn't progress much. I redesigned the HMD to fit in a snowboard helmet but I didn't finish it yet.
Don't worry I will post updates when I make some progress

I've always thought about using lenses and image distortion to get a quick and dirty high fov.

Man, did I call it or what?!

http://kotaku.com/5916210/carmack-being ... est-people

You did call it! Then again, I had already sent Carmack that prototype HMD before you did.

Hello guys !

With all the stuff around about Palmer's awesome HMD and John Carmack promoting VR, I gathered my motivation back to finish this project
Since the RIFT works on the same concept, I know there will be some video games for it (Doom 3 BFG and any game with Cybereality/Emerson custom drivers).
Here are its specifications :

resolution : 640x768 per eye
HFOV : ~130° (I'm not sure of it but it is greater than binocular vision which is 120°)
VFOV : full
weight : 800gr without the straps; 1kg with them (It's pretty heavy I know, but the system I built to tie the HMD to the head is quite comfy)
input : HDMI (although the controller board can take VGA and component video, I just didn't need them so I didn't make holes for it in the plastic case)

the screen is still the same : Sharp 7.2" LQ072K1LA03 1280x768
and the optics are the same as in the OP (I tried different lenses but finally the aspheric ones are the best I found for this screen)

I did not mount the lenses on an IPD or focal adjustable system (It was too complicated to design in a DIY way for me :p) but it's not a problem, the exit pupil is huge so there is no need for IPD adjustability and the focus is set to infinity.

The binocular vision covers the central part of the screen and leaves the egdes of the screen for peripheral vision. Unlike the RIFT, the centers of the stereo images need to be shifted toward the center of the screen.

Here is a picture with the centers of the images in front of each lens


And here the same picture, zoomed and shifted in order to keep the centers at the same location but using the all panel


Could you (Cybereality and/or Emerson) take that into account if you make parameters for your video drivers?

For my tests I used 3D videos and the excellent player Bino3D which allow me to set the parallax (I set it to -1 (the minimum)) but it is not possible to zoom the image so I loose the pixels on the edges (and so I loose a little HFOV).
Maybe I should try to modify it (its source code is available).




but what I'm interested in, is games (with headtracking)
I never tried an HMD before this one (I ordered a ST1080 but I'm still waiting for the french customs to stop retaining it)
I'll wait to see what's happening with the Oculus RIFT and I'll buy the same headtracker (Hillcrest ?)

Enough talk, here are some photos and videos

during the development :





final version :




the videos (wip) :





I can take more pictures of it if you want, feel free to ask any question

Absolutely brilliant work. Where did you get the screen from and do you know what its specs are (switching time etc)? Really well done you must be chuffed to get it finished finally.

Thanks
All I needed was motivation, It took me 2 weeks to finish it and it was almost in the same state as it was 1 year ago.
I got it from taobao but I made the guy at vitrolight buy it for me because I don't understand a single word in Chinese (I payed 280$ with the controller board and the additional charge from vitrolight, but we were in 2010 so I guess you can have it for less now).

About the specs, I don't know. I found this site http://www.panelook.com/LQ072K1LA03_SHARP_7.2_LCM_parameter_9671.html

Response time: 45(Typ.)(Tr+Td)

I guess it's in milliseconds, but I have no idea what "(Typ.)(Td+Tr)" means ^^

Hey, nice HMD, good to see you continuing this.

I guess the optics must be quite heavy and account for a big part of the weight of your HMD, do you have an idea of their specific weight ? Did you try to find similar optics using other materials with less density, like CR-39 or polycarbonate which are used in ophtalmic lenses ?

Great job. Palmer has really inspired a whirl-wind of activity around here and the larger gaming community.

Wow! 130 degrees sounds sick. You should be able to use my driver with this since its so similar to the Rift. In terms of moving the center of the image, this can be done with the convergence controls, which are already somewhat working (at least with L4D). Again, nice work.

@Fredz

Each lens is about 60gr so it's a big part of the total weight but not that much.
I didn't try to find them made of other materials, I didn't think about that (I'll try to search tonight, thanks )
Each box (one with the screen and the lenses, the other with the controller board) weighs about 400gr.
According to the specs on the site I mentioned above, the screen weighs 150gr, that means the plastic box is about 130gr
If I make another HMD, I'll try to reduce the weight of the box ^^ (The essential parts (screen and lenses) are actually pretty light : 270gr)

@brantlew

you're right, without Palmer I would have probably left the parts of this HMD in the corner of the room for years^^

@Cybereality

Nice! I can't wait to test it L4D is fine for me, I only have a 2009 macbook and L4D is one of the games that runs flawlessly on it (on win7 with bootcamp, not OSX).

Nice that the weight is not that high, with organic materials you could divide it by two but I'm not so sure it's that important now.

I looked up the characteristics of Pyrex and it looks quite good. I don't know much about optics but the Abbe number is quite high, which should mean there is even less chromatic abberation or dispersion than with glass or CR-39.

I think I'll have a try with these lenses, they don't cost that much and can be bought in France, that's pretty nice. I've got an antique laptop with a 5.6" 1024x600 display, do you think it would be suitable for these lenses or does the screen need to be larger ?

Yes I think about making a new box out of polystyrene but not in a near future (and I don't know yet how to do it anyways^^) (or maybe polyurethane foam injected in a mold)
The best would be to have a really light box to set the weight of the front box to ~300gr (screen + lenses + box) and have the controller board externalized (so you can carry it in a backpack for example like the PR3 from Palmer). I made a 25cm extension for the LVDS cable and it seems to work fine, but it should be a lot longer..

About Pyrex, now that you mentioned it, I didn't notice chromatic abberations

For a 5.6" screen it should work but keep in mind that the diameter of the lenses is 51mm and you can't place your eye in front of the optical center of the lens unless you manage to bevel it (I didn't try to do that because I don't have the equipment to cut glass or Pyrex). In my case it's a good thing, because it causes a lens shift effect that shifts the center of the half images toward the center of the screen

I'm not sure I follow you, why can't you place your eye in front of the optical center, because the light would be concentrated here ? My 5.6" display has a width of around 13cm, so I guess I can tilt the lenses in the same way you did, right ?

Unless you have a wide IPD and a thin nose, you can't place your eye centers in front of the optical centers of the lenses because they are too large (51mm) (look at my porfile picture for an illustration (and I'm not cross-eyeing ^^), not because it won't work (all the rays from the screen come parallel out of the lenses (if you set them at focal distance). I don't tilt the lenses anymore, it result in too much distortion on the edges of the screen (I chose to shift the images in software instead in addition to the lens shift effect to have the centers of the images at the right location)

Can you grind off the inside edges of the lenses, to allow them to be properly centered?

Joe Dunfee

I'm not sure if pyrex can be grinded easily and which tool to utilize but if Fredz can do it I will be pleased to hear about it

Love the high FOV you have achieved Foisi, great work!

Thanks

Fredz, I don't know if you ordered your lenses already but it seems that the website has only 1 lens left in stock and they will not have more until the end of the year...

Nope I didn't bought them yet, I'll need to do some tests to see if I can find a viable design.

And thanks for your answers, I completely forgot I had a nose...

I've started working on a software that simulates what is really seen by the eyes given a display (or two) and two lenses (or four). I'll incorporate eyeball size, IPD and different nose configurations too (I don't know how yet for this one) to have a good idea of what the end result would be in terms of FOV. I'll try to incorporate chromatic abberation using refractive indexes of the lenses by tracing different rays for RGB keypoints. If I'm able to go to this point I'll also try to simulate eye accommodation to see how the blurring varies on the end result.

Are you using Blender (IIRC you mentioned the idea of using it in another thread) ?

Yes, I wanted to use Blender at first but I think I'll not have enough control with it. I've started implementing a native application instead, using Lazarus (a multi-platform Delphi clone) and OpenGL rendering.

I posted this on another old thread, not wanting to start a new thread, but perhaps I should have posted it here.

I came across a good source for used or surplus lenses. They have indexed everthing. The prices are not junk-yard level, but the lenses are well cared for and not just thrown in a bin unprotected. Most average lenses are $4. Shipping is $5, regardless of size of order.

They mostly do mail order, but do have Saturday hours for in-person visits. They are particularly well known for surplus optics. They have a search tool for optics and also for machine gears.

Surplus Shed
1050 Maidencreek Road
Fleetwood, PA 19522
Phone Toll Free in U.S.: 1.877-7SURPLUS (78-7758)
Outside U.S.: 610-926-9226
open for visitors every Saturday from 8:30 AM to 2:30 PM.
www.surplusshed.com
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Joe Dunfee