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Galaxy5
Posts: 25
Joined: Tue Dec 24, 2019 11:11 pm

Live Hologram Display

Mon Jan 06, 2020 3:22 am

I've seen others make a holographic display using a RPi, monitor, and a glass prism. The only thing the Pi is doing is playing back a pre-rendered video. But, is there a way/software program to convert live display feed into the 4-sided format used with the prism? I can imagine it being really cool to use the whole desktop in 3d, live (I don't expect things like individual icons in 3d, just the flat desktop).
Thanks!

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perfo
Posts: 102
Joined: Mon Jan 30, 2012 2:42 am

Re: Live Hologram Display

Fri Jan 10, 2020 4:48 pm

I guess you mean the Hologram effects shown on YouTube and the like made from a bit of plastic cut and stuck together like an truncated , inverted pyramid and placed on a screen?

If so then I agree they do look great and I have made a couple myself. As for you application, do you need to to see the image from four sides ? if it is only the desk top you want to show then maybe a single refection (Peppers Ghost) may do you and this is of course extremely simple.
When playing with these things I didn't find any software that could turn a video stream in to the four distorted images so Sorry I can't help you there but if you find one then please post it.

An interesting add on is to use some thing like the leap motion controller and having a 3d hand in your scene clicking on the icons.

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Galaxy5
Posts: 25
Joined: Tue Dec 24, 2019 11:11 pm

Re: Live Hologram Display

Sun Jan 19, 2020 1:05 am

Interesting ideas. Never thought about a one-sided display, which would only need a "normal" display and one angled piece of plastic/glass, right?

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perfo
Posts: 102
Joined: Mon Jan 30, 2012 2:42 am

Re: Live Hologram Display

Sun Jan 19, 2020 1:57 pm

Yep just a flat piece of glass, perspex etc. With something black behind and either side it will still look the part from the front. The image will be a little distorted depending on what angle you put the glass at. But I've found this may or may not be a problem depending on what you are displaying. The distortion is caused by the height of the image on the real screen being different to the height on the glass. The width should be the same and there isn't a vanishing point as in the four image type display so is a lot easier to fiddle with and like I said you may not need to fiddle at all. For example if your glass screen is 45 degrees from the actual and the image on the actual was 20 cm by 20 cm then the image on the glass will be 20 cm wide by about 28 cm tall (may make a person look taller and slimmer :-))

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rpdom
Posts: 17732
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: Live Hologram Display

Mon Jan 27, 2020 10:45 am

Silky81 wrote:
Mon Jan 27, 2020 10:09 am
What exactly is perspex? Never heard of it.
Also know as "Plexiglass" in some places, I believe, or more generically Acrylic.
Unreadable squiggle

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perfo
Posts: 102
Joined: Mon Jan 30, 2012 2:42 am

Re: Live Hologram Display

Mon Jan 27, 2020 5:46 pm

Poly(methyl methacrylate)

Chemical Compound



Poly(methyl methacrylate)

Poly(methyl methacrylate), also known as acrylic, acrylic glass, or plexiglass as well as by the trade names Crylux, Plexiglas, Acrylite, Lucite, Perclax and Perspex among several others, is a transparent thermoplastic often used in sheet form as a lightweight or shatter-resistant alternative to glass. The same material can be used as a casting resin, in inks and coatings, and has many other uses.

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