holus - glassless 3d system and modular apparatus

Dr D, Kais & Dhruv Adhia – H+ & UBC

© Kais Dridi & Dhruv Adhia

Glassless Tabletop 3D system for MulDple Users

Using a source rectangle plus a slide / 1-‐ the pyramid case

object

source

detector

image

The resulted image can sDll be seen even though with much lower resoluDon. The key point is there is no distorDon.

1

Change the source here, as if rays have ben launched from a 2D screen.


Using a source rectangle plus a slide / 2-‐ the cone case

source

detector

image

2

object


Using a source rectangle plus a slide / 2-‐ the cone case – second config.

3

Just moved up the source and adjust the posiDon and widths of the detector (trying to capture the whole image). The resulted image is completely distorted in both direcDons, with a heavy distorDon within the lateral direcDon, as expected.


4

Play a lit bit with the source pixels posiDons (±), the pixels at image can be aligned; however, nothing changes in the lateral direcDon in terms of ray divergence, which has a direct impact on the distorDon of the image.


5

If we increase the number of pixels (say, array of 4×5 rays)

@ source detector

@ image detector

source

image


6

source

reverse case checked P

source

the idea here is to do a “side” projecDon (i.e. put the source matrix beside the cone, not on the top as previously).


7

to display a parDcular view (‘slot’) of the 3D object, say a rectangle for example, two requirements must be saDsfied:

1) the pixels of that parDcular “slot” must be re-‐arranged in a very parDcular manner that depends on the size of the slot, and all the geometry involved in the system.

2) parDcular designed opDcs (e.g. lenDcular lens sheets/mirrors??) whose role is to direct rays towards specific points on the cone screen, so that when rays are reflected, we obtain see the exact shape we want.

both points (1) and (2) will require precise geometrical posiDons (i.e. coordinates) of the pixels (i.e. sources) with respect to the cone.


8

Therefore, the key point here is that to be able to see a side of a given character displayed on a cone side – without distorDon – we need to know what should be the pixels’ posiDons on the 2D display screen (posiDons = x, y, and z coordinates, plus the angles – i.e. the direcDon cosines of the rays that will be emiged from the pixels).

1 – Take one side of the character;

2 – Project it on the cone from the viewer plane (i.e. as if the viewer is watching the character side w/o distorDon);

3 – Save the data (pixels) on the detector (data = X, Y, Z, plus direcDon cosines);

4 – Take these data and re-‐simulate the system (with Zemax) – just as a mager of verificaDon;

5 – A – Program the data on a real 2D display screen; B – Think of what opDcs should be designed to match the exact pixels and bend the rays to their exact posiDons

The idea is to reverse things and imagine that we are seeing a true image from one cone side – as with the pyramid – in front of our eyes. This means in other words that parallel rays are coming towards our eyes without any divergence in any direcDon. This means also that all the pixels have been projected equidistantly….to do this let’s imagine that our source is projecDng images from the side of the cone rather than from its top. Amer the projecDon a detector can read the different coordinates on the display screen. This will lead us to generate sources/rays from these coordinates so that when they get projected toward our eyes, we get the right image.

Summary…


9

Seong a frame/template to know the maximum size of a character to be displayed.


10

It is very important to define what is the maximum area that one can use to display a parDcular side of an object. This ensure that we can project/display any side within that sort of “frame”.


11

How the pixels within the 2D screen look like, when we consider two sides, of a given digital asset


12

z

x y α β

γ

The opDcs side


13

The opDcs side


14 © Kais Dridi -‐ UBC

One can think of a matrix of mirrors, where each one of them can reflect a ray into a parDcular direcDon. Array for one direcDon projecDon (i.e. one side)

For the moment, assuming the distance between pixels is ~ 80-‐100 μm, a feature of 10-‐20 μm will be very suitable

The opDcs side


15 © Kais Dridi & Dhruv Adhia

16

Get an idea about the size/dimensions

Digital Micro-‐mirror Device (DMD) from Texas Instruments


17

Get an idea about the size/dimensions

Digital Micro-‐mirror Device (DMD) from Texas Instruments


For a cone (r2, r1, h = 5, 0.5, 4.5)

Source point (1W) cone ang 10°

Total power = 0.846 W

ProjecDon from a source point – into a cone


Total power = 0.943 W

Source point (1W) cone angle 10°

ProjecDon from a source point – into a pyramid


the idea here is to do a “side” projecDon (i.e. put the source matrix beside the cone, not on the top as previously).

source source

image

exchange: image ßà source? © Kais Dridi & Dhruv Adhia

The following is when z2 of the cone is changed to 5.5, so that alpha becomes ~ 33°.

Effect of angle of cone edge line (to be studied further, using the opDmizaDon tool of Zemax).


Part 2 – LenDcular lens as a layer


LenDcular Array

The lens is used to create lem eye and Right eye image giving depth to the informaDon


Embedding lenDcular lens setup

Every slit on lenDcular lens magnifies different image. In the case of Holus, we render 36 different views. 9 views are rendered per side of pyramid structure. The lens further magnifies different perspecDve based On user posiDon which overcomes the need of posiDon Tracking or eye tracking providing glassless 3D Experience.


Glassless 3D displays have a “parallax barrier” that directs different light into each of your eyes when you enable the 3D feature. With the 3D feature disabled, the barrier is disabled so the same light reaches both of your eyes, resulKng in the 2D look. With 3D enabled, bits of the light are blocked from reaching either eye. Each eye sees a different image, creaKng the 3D look and the illusion of depth in your brain.

Credits


Holus ProjecDon mediums opDons

Requires two layers, one for reorienDng light using MEMS system and another using lenDcular lens

Requires one layer just for lenDcular lens


Conclusion The purpose of such a setup is to keep the enKre system cost effecKve and high resoluKon. Similar system has been achieved, it however requires 103 micro projectors in order achieve 360 degree experience as shown in the figure below. Each perspecKve is 100x100 pixels in resoluKon. With Holus setup we are able to over the low image quality and cost of setup. Current challenges do include on requirement of high end CPUs such as Intel Xeon E5-‐2699 processor for 36 views to be simultaneously rendered where each view includes le[ eye and right eye perspecKve.


holus - glassless 3d system and modular apparatus

Technology