(feasibility of) DIY near-eye light field display

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Flumble
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(feasibility of) DIY near-eye light field display

Postby Flumble » Sat Mar 12, 2016 12:41 pm UTC

A couple of years ago, some researcher at NVIDIA demoed his approach to a light field display. Here's a presentation at AWE about it.
Now there are all these excuses for why it's not a consumer product yet (blah blah resolution), and with it numerous other light field technologies/approaches. But frankly, I don't care about resolution, I just want a working prototype of a head-mounted display that doesn't have bulky (expensive) lenses and that allows you to focus. And preferably one that doesn't care about your eye prescription.

Like I said, there are multiple approaches to creating a light field: a single display with a microlens array in front (Douglas' presentation), a single display with a pinhole mask in front and a regular lens, a stack of displays with regular lenses and probably more.

The biggest obstacles (to me) currently are finding high-resolution microdisplays (the best option for now is a second-hand HMZ-T1 for 350-odd $ or €) and the cost of a microlens array or pinhole mask. Does anyone even make such arrays?

Suggestions, ideas, answers and questions are all welcome. (And if you suggest "just forget about it", make sure to include some reasons :wink: )

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Re: (feasibility of) DIY near-eye light field display

Postby Neil_Boekend » Fri Mar 25, 2016 1:13 pm UTC

AFAIK micro displays are used in camcorder eyepieces. I believe DV camcorders used them and they are now obsolete. You might be able to find them in a yard sale or so, or maybe some of your family has one of these spare.

Edit: oh, and come to think of it: microlens arrays are used in those moving baseball cards. Dunno if the quality and the exact dimensions match your requirements though.
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Re: (feasibility of) DIY near-eye light field display

Postby Cave Wizard » Sun Apr 24, 2016 3:14 pm UTC

Hey dude, I have an old HMZ T1 I'd be happy to mod for this, if you can explain what you want me to do with it. I'm somewhat handy, but don't know anything about microlenses
Last edited by Cave Wizard on Sat Feb 25, 2017 7:47 pm UTC, edited 1 time in total.

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Re: (feasibility of) DIY near-eye light field display

Postby mosc » Thu Apr 28, 2016 11:13 am UTC

If you had a sufficiently fast camera (readout speed wise) and you could program in focus bracketing, you can get the same results as long as the scene is static.
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Re: (feasibility of) DIY near-eye light field display

Postby Flumble » Fri Apr 29, 2016 5:13 pm UTC

Neil_Boekend wrote:AFAIK micro displays are used in camcorder eyepieces. I believe DV camcorders used them and they are now obsolete. You might be able to find them in a yard sale or so, or maybe some of your family has one of these spare.

Edit: oh, and come to think of it: microlens arrays are used in those moving baseball cards. Dunno if the quality and the exact dimensions match your requirements though.

Good suggestions. Unfortunately most camcorders/cameras I have found so far have such low resolution displays that they don't fit the criterium of "I don't care about resolution". Moreover I'm not sure if those displays communicate via a standard protocol.
The '3D layer' of trading/collecting cards and flippos are a bit too small, but I do remember a toy with a larger pattern (it had a paper roll behind the pane that would appear as very choppy animation while scrolling the paper). I have no idea how two 'striped' layers compare to one layer with round lenses, but it's worth a shot.

In any case, I'll put the project on hold until after my vive has arrived and I'm done with being in constant awe of the 'normal' VR experience.

mosc wrote:If you had a sufficiently fast camera (readout speed wise) and you could program in focus bracketing, you can get the same results as long as the scene is static.

Not sure if we're on the same subject; do you mean to track the position of your eyes to find out at what depth you're trying to focus and then render the scene with DoF (blurring everything nearer and further than the focus depth)? That would still leave you with one actual focus depth at infinity (or closer, depending on the lens and your prescription).

Cave Wizard wrote:Hey dude, I have an old HMZ T1 I'd be happy to mod for this, if you can explain what you want me to do with it. I'm somewhat handy, but don't know anything about microlenses

Well, what you need is either a microlens array* or a pinhole mask. For the pinhole mask you need a very precise printer that can handle transparent film as mentioned in one DIY guide. If I recall correctly, the NVIDIA demo had lenses that covered about 16x16 pixels**, so you need to calculate the best pinhole size, grid size and and spacing between the display and the mask, based on the distance between the HMD display and your eyes and the size and resolution of the display.

*I have no idea how things go around at MS, but maybe you can just walk by the optics department and ask if they have a discarded array? It does require 3 miracles: there being an optics department, being able to enter that department and them working with microlenses. Oh and you should be free to take discarded stuff with you for hobby purposes.

**not sure if that means 256 light directions for the microlens setup, but it surely does for a pinhole mask. And for flat surfaces perpendicular to your viewing direction it probably means that you reduce the resolution by a factor of 16 in both directions.


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