Parallax Barrier Screen for Head Mounted Display ?

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budda
Sharp Eyed Eagle!
Posts: 388
Joined: Thu May 22, 2008 9:13 pm

Parallax Barrier Screen for Head Mounted Display ?

Post by budda »

Hi,

I have been playing some Nintendo 3DS games up close with high powered reading glasses and the effect is quite immersive - in a cartoon sense.

The 3DS uses a parallax barrier display and works surprisingly well in the viewing sweet spot.

However, the 3DS needs to be held in such a way as to still access the controls and the lower touch screen with the hands. The parallax effect was neither designed nor intended for such close-up stereo viewing.

Perhaps a parallax barrier display could be incorporated into a fixed head mounted display.

Some of the advantages for a parallax barrier HMD over the current generation of 'in your face with a mobile phone screen' head mounted displays are:


1. Can use a larger display with a lower pixel density

2. No need for a central dividing barrier (vertically interlaced vs side-by-side)

3. Fixed parallax barrier with respect to the left and right eyes (no ghosting)

4. Relaxed lens optics


Disadvantages:


5. More pronounced screen door effect due to the vertical interleaving of views.


If such a head mounted display were employed, there would be greater design flexibility and more economical construction possibilities available than the extreme engineering being seen in some of the latest models of head mounted displays.

Maybe Nintendo could make this system work as an extension of their 3DS gaming technology.


Thanks.
budda
Sharp Eyed Eagle!
Posts: 388
Joined: Thu May 22, 2008 9:13 pm

Re: Parallax Barrier Screen for Head Mounted Display ?

Post by budda »

Hi,

Our very own MTBS3D cybereality posted an extensive thread on MTBS3D forums under - [DIY] Auto-Stereo with Parallax Barriers.

For some background information see it here:

http://www.mtbs3d.com/phpBB/viewtopic.p ... &start=191

This technology is quite effective at generating 3D from conventional 2D off-the-shelf displays.

It should not be difficult in principle to adapt parallax barriers for use in near-eye head mounted displays. The spacing of the barriers need to be computed and printed - taking into account the screen itself and the viewers fixed perspective.

Anyone got an app for that ...

Thanks.
budda
Sharp Eyed Eagle!
Posts: 388
Joined: Thu May 22, 2008 9:13 pm

Re: Parallax Barrier Screen for Head Mounted Display ?

Post by budda »

Hi,

There is a high quality tablet model that can be repurposed as a near-eye head mounted display fitted with a parallax barrier for 3D viewing.

Its the new Samsung Galaxy Tab S 10.5 .

These are the features which make it a good candidate for prototyping.

- Amoled display
- RGB Stripe
- 287 pixels per inch
- 2560 x 1600 pixels
- 16:10 aspect ratio
- 10.5 inch diagonal
- stereo speakers located at the side edges (in landscape mode)

Also, from the DisplayMate website at http://www.displaymate.com/OLED_Tablet_ShootOut_1.htm it states:
Best Tablet Display: Based on our extensive Lab tests and measurements, the Galaxy Tab S is the Best Performing Tablet Display that we have ever tested, not surprisingly with performance that is almost identical to the OLED Galaxy S5 Smartphone that we recently tested and found to be the Best Performing Smartphone Display. The Galaxy Tab S establishes new records for best Tablet display performance in: Highest Color Accuracy, Infinite Contrast Ratio, Lowest Screen Reflectance, and smallest Brightness Variation with Viewing Angle.
Although it weighs about 460 grams, it could be lightened with the removal of the internal 7,900mAh battery.

The full specs for the Samsung Galaxy Tab S can be found here:

http://www.samsung.com/global/microsite ... specs.html


Thanks.
budda
Sharp Eyed Eagle!
Posts: 388
Joined: Thu May 22, 2008 9:13 pm

Re: Parallax Barrier Screen for Head Mounted Display ?

Post by budda »

Hi,

I have been wondering about the methods needed to create a high resolution parallax barrier.

Inkjet printing from a desktop printer may not be sufficient for making high-end parallax barriers.

A ballpark printing resolution requirement is 4000 dpi to 6000 dpi (dots per inch).

It seems Colour Transparencies may fit this requirement. These are basically high technology slides for projectors. These Colour Slide Films come in a standard size of 8 x 10 inches, which make them suitably sized for covering head mounted displays.

They can be expensive to produce, with costs rising depending of the resolution demanded. Ultimately the output quality is only as good as the grain size within the photographic emulsion of the film.

With a commercial Film Recorder, digital files can be drawn on transparencies and developed like regular film.

Black and White (Clear) transparencies can be made for classical parallax barriers, however Colour Transparencies may have added benefits.

The advantage of colour transparencies is that the edges of the bars in the parallax barrier can be blended with suitable masking colours to isolate crosstalk from adjacent pixels.

For instance in the red-green-blue vertical pixel format - for example - cyan (blue and green) can be used on one side of the black bar to block red subpixel crosstalk, and yellow (green and red) can be used on the other side of the black bar to block blue subpixel crosstalk. Essentially with green in the middle of the pixel window, it has the least concern for crosstalk - as presented in this case.

Used in this way, the alignment requirements of the parallax barrier are slightly relaxed, whilst ideally preserving image colour quality.

A possible advantage of film recorded transparencies is the continuous analog-like drawing of image lines on the film which gives it smoothly blended edge transitions at the finest scale.

This method of generating parallax barriers is suitable for prototyping, but probably not suitable for economical mass production.

Thanks.
FMPrime
One Eyed Hopeful
Posts: 23
Joined: Wed Sep 25, 2013 12:36 am

Re: Parallax Barrier Screen for Head Mounted Display ?

Post by FMPrime »

Budda, I had a very similar idea that I've yet to try. Using disposable camera film negatives.

Display a negative of the desired parallax barrier on a computer screen, take a picture with a disposable camera, get the film developed and use the film as the actual barrier.

It would take some experimentation to get the size/spacing correct, but it may be worth a shot for cheap prototyping purposes.
metronome
Cross Eyed!
Posts: 114
Joined: Sat Mar 16, 2013 12:42 pm

Re: Parallax Barrier Screen for Head Mounted Display ?

Post by metronome »

I was thinking what it would be like using the LG Optimus 3D phone in a HMD holder :P
Not sure if it would have desired effect though!
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