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  • Mon 23 Nov 2009

    Stereoscopy for two users

    Published at 17:07   Category VR Displays  

    How would you allow two users in front of a projection screen to each have their own stereo ?

    I’ve seen such a system in Weimar at IPT/EGVE 2007 and I hear several systems are starting to use this.

    So here are three methods, demonstrated thanks to my Advanced Sketching System (c) :

    Method 1 : Users are separated through a polarized filter


    This can be seen as a regular active stereoscopy system.

    The system has two active projectors, one polarization filter in front of each projector, regular shutter glasses plus matching polarization filters.

    Thanks to the polarization, each user sees only one (active) projector. Each projector displays left and right image as is regularly done with active projectors.

    In theory, you have it, each user sees in stereo ! This is the “easy” way which doesn’t need too much modification apart from adding polarized filters on shutter glasses.

    The active stereo provides a good separation between left and right eyes, but the polarization separation is not perfect, so each user sees a ghost image of the other user.

    This unperfect separation of polarized filters is less problematic when it is used for only one user since the left and right images aren’t that much different. But when you see the picture of another user, it is potentially very different and can also move while you are static. That’s a real presence breaker !

    So let’s try another way :

    Method 2: Users are separated through a shutter mechanism


    Now this can be seen as a regular passive stereoscopy system. For each user, the left/right images are separated thanks to a polarized filter.

    The tricky part : The first (active) projector displays the left image for user 1, then the left image for user 2. At the same time, the second (active) projector display the right image for user 1, then the right image for user 2.

    This means that half the time you can see the left and right images for user 1, then half the time you see the left and right images for user 2.

    But how can you hide the left/right images of the other user ? With modified shutter glasses that shut both eyes at the same time rather than each eye alternatively !

    This method also requires some tricks on the image generator. Often times the generation of left/right images in quad buffers is hardwired in the renderer, so you need a system that is flexible enough to allow the generation of two left images instead of left/right.

    Method 3 : multiple time splices

    Another way is to take the same approach as the active stereoscopy that also requires hardware modifications : draw each image sequentially : User 1 Left, User 1 Right, User 2 Left, User 2 Right, User 3 …

    Shutter glasses would then open only for User 1 left eye, all other eyes/users being shut, then User 1 right eye, etc.

    This has several implications, ranging from flickering if the projector frequency is not enough, to decreased luminosity. You also need special shutter glasses and software to support all this.


    This is not an easy topic! But an important one if we want real cooperation. I’ve left the option for multiple HMDs aside because you don’t see the other user, and some people just don’t want to wear HMDs.

    I’m sure others methods exist, such as this one presented at IEEE VR 2009: Image Blending and View Clustering for Multi-Viewer Immersive Projection Environments, Jonathan Marbach

    Do you know other methods ?

    Mon 9 Nov 2009

    Characteristics of Professional HMDs, by Sensics

    Published at 16:50   Category VR Displays  

    Sensics, makers of the renowned piSight HMDs has released a very interesting white paper called “Characteristics of Professional HMDs“.

    Here’s the introduction :

    As of July 2009, the perfect head mounted display (HMD) – the one providing exceptional immersion, superb image quality, a wireless and featherweight design for a ridiculously low price – does not exist. However, many users might find that a ‘good enough’ HMD can be found for their particular application. This document discusses the key attributes for HMDs, explains why they might be important, and offers some selection guidelines.

    Thanks to them for writing and sharing this document !

    Tue 27 Oct 2009

    Cheap DIY HMD

    Published at 14:00   Category VR Displays, Virtual Reality DIY  

    What can I say ? That’s the future !

    YouTube Preview Image
    Tue 20 Oct 2009

    Twister Immersive AutoStereoscopic Display

    Published at 12:59   Category VR Displays  

    Here’s an incredible display : Twister – Telexistence Wide-angle Immersive STEReoscope by the Tachi Lab (again!)

    (Via PinkTentacle via ImmersiveTech blog )

    YouTube Preview Image

    It’s somewhat big but very interesting and autostereoscopic around 360° !

    Fri 21 Aug 2009

    On the way to flat displays for caves

    Published at 9:02   Category VR Displays  

    The guys behind the StarCave have created a new VR display using flat HDTV.

    From this Physorg article :

    The technology, dubbed “NexCAVE,” was inspired by Calit2′s StarCAVE environment and designed and developed by Calit2 Research Scientist Tom DeFanti, Virtual Reality Design Engineer Greg Dawe, Project Scientist Jürgen Schulze and Visualization Specialist Andrew Prudhomme.

    “It’s always been our dream to make a projector-free LCD flat panel CAVE,” DeFanti says. “The trick was to get the form of the huge StarCAVE into the space of a living room. We took a speculative leap by overlapping 9 panels, and it turned out better than we thought.”

    “The NexCAVE’s technology delivers a faithful, deep 3-D experience with great color saturation, contrast and really good stereo separation,” explains DeFanti. “The JVC panels’ xpol technology circularly polarizes successive lines of the screen clockwise and anticlockwise and the glasses you wear make you see, in each eye, either the clockwise or anticlockwise images. This way, the data appears in three dimensions. Since these HDTVs are very bright, 3-D data in motion can be viewed in a very bright environment, even with the lights in the room on.

    “Lights-on is something that just wasn’t possible with the StarCAVE.”

    The NexCAVE’s data resolution is also superb, close to human visual acuity (or 20/20 vision), DeFanti says. The 9-panel, 3-column prototype that his team developed for Calit2′s VirtuLab has a 6000×1500 pixel resolution, while the 21-panel, 7-column version being built for KAUST boasts 15,000×1500-pixel resolution.


    The costs for the NexCAVE in comparison to the StarCAVE are also considerably cheaper. The 9-panel version cost DeFanti’s team under $100,000 to construct, whereas the StarCAVE is valued at $1 million. One-third of that cost comes from the StarCAVE’s projectors, which burn through $15,000 in bulbs per year. Every time a projector needs to be relamped, the research team must readjust the color balance and alignment, which is a long, involved process.

    Since the NexCAVE requires no projector, those costs and alignment issues are eliminated.

    “The fact is, with the StarCAVE, there’s lots of tuning involved if you really want to get it right. It’s like tuning a piano,” DeFanti says. “With the NexCAVE, you don’t have to tune once it’s built.”

    The NexCAVE’S tracker (the device used to manipulate data) is also far less expensive — it’s only $5,000 as compared to the StarCAVE’s $75,000 tracker, although its range is more limited.


    “Our next goal is to make an autostereo NexCAVE,” says DeFanti (meaning the screens won’t require the use of special glasses). “And someday we hope to have organic LED screens with no bezels.

    They say that the seams are not visible since you are so immersed! Sounds like a nice display to me.

    I just bought myself a Samsung RZ 2233 120H LCD screen and the nVidia 3D Vision kit with stereo glasses and it rocks!

    Now I want to have 9 to build myself a NexCAVE =)

    Fri 7 Aug 2009


    Published at 14:18   Category VR Devices, VR Displays  

    A plastic gun, a LCD, a Gyromouse, mix, shake, here’s the VR Gun :

    YouTube Preview Image YouTube Preview Image


    (I know, I’m two months late =)

    You will only get the rotations from the Gyromouse, so walking won’t help you.

    This is as clever as the R-Screen or the Virtual Showcase, but less complicated and cheaper =)

    Wed 15 Jul 2009

    3D photo (by Fuji)

    Published at 13:39   Category VR Displays  


    Last year, Fuji announced a set of devices to capture/display 3d pictures. Now this is getting closer to reality. This 3D camera has two lenses and an autostereoscopic LCD on the back.

    Back at Dimension3, I had the chance to test a cell phone with stereo capture and autostereo screen, and it worked much better than I expected, so I’m quite optimistic about this!

    <nearly out of topic>

    I nearly bought a stereo lens for my DSLR but some other 3D geeks told me that by ‘simply’ taking two pictures with the help of a special tripod head it was easy and less expensive. But it only works for very static objects.

    I’ve heard that people taking pictures for autostereoscopic prints are doing exactly this, with some automation. The camera slides quite fast on a trail and shoot as many pictures as needed (from 8 to much more) in a short timeframe. The geeks from Alioscopy even created an asymmetric camera where the sensors slides, in exactly the same way and for the same reasons as our VR asymmetric cameras do!

    </nearly out of topic>

    But of course taking two pictures at the same time is the easiest way to go, and it’s really nice to see that this is coming to 3D geeks near you, and I hope this will reach even more people than that!

    Fuji also plans to have sell an autostereoscopic photo frame, and an online service to print lenticular pictures.


    From Electronista :

    The 10-megapixel 3D camera will first appear in Japan sometime this summer, while Europe and the US will get it during September. Pricing will be set at around $600, with the photo frame costing a few hundred dollars as well. Prices haven’t been set yet for prints, though Fujifilm doesn’t anticipate customers accepting high prices.

    From me :

    I can’t wait to have to manually adjust my convergence settings =)

    Sat 11 Jul 2009


    Published at 10:50   Category VR Displays  

    I’ve just found myself wanting to test some OpenGL stereo and I couldn’t find the old-school OglPlane.exe program.

    It’s a simple program opening an OpenGL window with quad-buffer stereo and displaying a stereoscopic wireframe paper plane :


    We use that regularly to debug stereo :

    Client: There is no stereo in Virtools! It’s all your fault, I hate you!

    Us: Could you run oglplane and tell us if it’s in stereo ?

    Client: No it’s not, I’m sure Virtools broke everything!

    Us: Could you activate the stereo in the graphics card drivers ?

    Client: Ha, now the plane is in stereo, but still not Virtools, you morons!

    Us: Could you change the Virtools stereo parameters ?

    No answer from client.

    Alright maybe it’s because of the Virtools’ documentation =)

    OglPlane was developped by Stereographics, makers of the famous 3d glasses and stereo handbook, which was bought by RealD.

    It seems the software was hosted on RealD website but I really can’t find it, so I got it on my work laptop and uploaded here:


    (If you’re from RealD, don’t sue me, let’s talk about it ;)

    The zip also contains the source code and visual studio project so you can also learn how to setup quad-buffered OpenGL.

    First edition : 1991. Wow, that’s really old-school 3D !!

    //  OGLPlane.cpp
    //  by Bob Akka, StereoGraphics Corporation, July 1998
    //  Some history:
    //      April 1991: Original SGI GL program, by Bob Akka, StereoGraphics.
    //      Date unknown: Converted to OpenGL by Silicon Graphics Corp.
    //      March 1995: Modified (Motif), by James S. Lipscomb and Keh-Shin Cheng,
    //          IBM Research.
    //      December 1996: Converted to use OpenGL Utility Toolkit,
    //          by Rick Hammerstone, Digital.
    //      February 1998: Converted to use WIN32 OpenGL GLAUX Toolkit,
    //          by Dave Milici, StereoGraphics.
    //      July 1998: Rewritten in plain OpenGL, for MFC Windows environment,
    //          program simplified in some ways, EnableStereoWindow() is brand new,
    //          DrawAirplane() carefully restored to original classic April 1991
    //          geometry, real-time stereo and rotation adjustments added, and…
    //          StereoProjection() overhauled & comments added (StereoProjection()
    //          is now so thoroughly commented that it is practically a tutorial),
    //          by Bob Akka, StereoGraphics.
    //      September 1999: Blueline index support added (this is used by some SGC
    //          hardware systems)
    //  Note: This program does not deal with the possible situation where the
    //      user switches Windows display settings while this program is running

    Thu 9 Jul 2009

    Autodesk stereoscopic whitepaper

    Published at 14:17   Category VR Displays  

    I’m working several projects recently, one of which you’ll soon hear about (and will be able to participate in ;)

    Autodesk has released a really interesting whitepaper on its Stereoscopic Filmmaking page :

    Read about the current state of the stereoscopic filmmaking industry, the business case of S3D, as well as the technical and creative considerations faced by those looking to make compelling stereoscopic movies.

    It covers a lot of the ground necessary to have a good understanding of stereoscopy. Of course a lot of this applies for VR and 3D games.

    Its older brother, the Stereographics Developpers Handbook, is still interesting though.


    Mon 15 Jun 2009

    Laval Virtual 2009

    Published at 22:35   Category Augmented Reality, VR Applications, VR Devices, VR Displays, Virtual Reality  


    The 11th edition of Laval Virtual has been held from the 22th to the 26th of April 2009, and to me it was one of the nicest edition ever!

    As the conference center was moved a bit further than usual, I didn’t take time to go there much. So I stayed on the tradeshow and took time to have long discussions and meet new people.

    We’re seeing more commercial/industrial applications as well as nVidia’s push to democratize 3d displays.

    We’ve already talked about Clarte’s R-Screen and Clarte’s Ergo-Wide3, but we didn’t talk about Clarte’s Sitac 3D!

    It’s a military project aimed at displaying a tactical situation to help with decision making and training. The interface and interactions are really nice and intuitive :


    Crescent was also present with an improved version of their wide-angle HMD and an application made by ESCIN students called Acrophobia, where you have to walk on the edge of a building. I’ve seen a lot of people freaking out because of the induced fear of heights, demonstrating a high sense of presence!

    YouTube Preview Image

    nVidia 3D Vision

    I’ve also been able to play with nVidia’s new stereoscopic system, 3D Vision :


    (in fact I think their should be some drivers work for WinXP too..)


    I have to say I was quite impressed by the quality of the stereo rendering, I’ll try to make a review when I can get my hands on this system for more time.

    Augmented Reality

    We’ve also already talked about the AR Games.

    New User Interfaces

    I could also test a neat MindManager software called MindFlow by Tony DaLuz from l’Ecole de Design de Nantes based on Immersion‘s multitouch table :



    mindflow, demonstration in Laval Virtual from Toni Da Luz on Vimeo.

    Immersion was also demonstrating its new cubic multitouch interface, the CubTile :

    YouTube Preview Image


    The MIT brought its impressive Nexi robot :


    Speaking of robots, the University of Tsukuba also demonstrated a vision system to recognize hand gestures and have it mimick by a robotic hand :

    YouTube Preview Image


    Still no big revolution this year except the R-Screen! Augmented Reality is growing in interesting applications, VR commercial applications are getting more complex, nVidia is getting back to the consumer stereoscopic business and thanks to the AFRV, the conference quality is increasing.

    So see you next year!

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