14:42 
VR Devices, Virtual Reality DIY
Kyle McDonald shows at Instructables.com how to make your own cheap 3d desktop tracker.
Here’s a small video (non embeddable in my wordpress..)
You need :
It’s using capacitive touch sensing.
How cool is that ?
18:01 Augmented Reality
From Monday 10th to Wednesday 12th March 2008 was the actual IEEE VR conference. See the complete program.
It was harder to take notes because there was no power plug in this room, and Wi-fi was having a hard time, so sorry if the report here is less complete. Moreover we had to hold the Virtools booth during pauses, which was pretty exhausting and caused us to miss some interesting presentations.
The first session was about Augmented/Mixed reality, and even during the other sessions, there was a lot of talk about AR! I’m wondering if this is because AR is trendy right now, but I’m pretty sure there are a lot of things to research in pure VR! Not that AR isn’t interesting, and of course there’s a lot of common ground, but it’s not my main field of interest. So maybe there should be a IEEE AR or a full AR session where all the AR specific topics are discussed ? Like markers /camera tracking, AR displays, AR applications etc.
An impressive tracking system based on visual/inertial fusion was presented by Gabriele Bleser and Didier Stricker (”Advanced tracking through efficient image processing and visual-inertial sensor fusion”). It is very robust and didn’t seem to have any visible latency, but it requires a textured-CAD model of the environment to be able to use an illumination model. Everyone in the room was stunned and I believe it’s the only time the public spontaneously applauded in the middle of the presentation!
Here are some summaries of papers.
Massively Multiplayer Online World as Platform for AR experiences
by Lang, MacIntyre, Jamard.
We have seen a prototype of augmented reality interface to Second Life; you could see SL avatars in the real world, which is really nice! Even more, an avatar inside SL can record its performance in the Augmented Reality and see that video inside SL! This mixing of real and virtual world makes me dizzy!! That’s a really nice application.
See http://arsecondlife.gvu.gatech.edu
Providing a wide field of view for AR
by
The first paper was about improving the field of view used for desktop AR to improve usability. By putting the camera on the user’s head and mosaicing (stitching) the views, the system can provide a proprioceptive match between the real and augmented world.
Displaying the whole interaction space shows better performance and usability, and it also reduces searching time and cognitive load.
But it seems that placing the camera in a fixed location close to the user’s head. The stiching errors, mainly due to motion blur, were the main concern of users but the mosaicing system can still be a good alternative if the camera cannot be fixed at the proper place or when it will be improved
Capturing images with sparse informational pixels using projected 3d tags
by
The goal of this team is to have tags in realworld to be seen by telephone cameras.
Some challenges in barcode recognition are tag distance and inclination, environment illumination.
Moreover, it requires attaching physical tags to the surface.
What is proposed here is to project optical tag with a projector. This allows to use, instead of a spatial pattern, have a temporal pattern, or a spatio temporal pattern. Moreover, the tags are projected in the infrared spectrum so are not visible by human eye or regular camera.
These tags allow to get information of real objects on cheap phone cameras with very limited computation power.
See http://www1.cs.columbia.edu/CAVE/projects/photo_tags/
Hear-through AR: using bone conduction to deliver spatial audio
by
See http://www.cs.wpi.edu/~gogo/hive
The goal is to augment reality of the auditory sense, not only visually as in traditionnal AR. We need CG and real world sound occlusion and reflection. Why use a bone conduction headset ? Because the real world is not occluded or modified in any way. But headphone accuracy is probably better. So a lot of work still has to be done to improve the system, both on the sound generation and the hardware, but the results of the study are very interesting.
1:17 Uncategorized
[23 Jul 2008: Added Optical Tracking video]
[6.03.08: Added Magnetic Haptics text&video]
[24.01.08: Added CirculaFloor video]
[21.01.08 : Added Virtusphere video]
- Tracking
- Gloves
- Haptics
Not so long ago, a VR system required a million-dollar supercomputer. Nowadays the top VR systems are using clusters of desktop computers, dramatically reducing the price and maintenance costs.
To be able to interact with a virtual world, the computer needs to know where your body stands through input devices called trackers.
The most common trackers used to be magnetic trackers, (Polhemus, Ascension) but they require cables (except the new Polhemus Patriot Wireless) and can lose precision as the magnetic field is perturbed by metal.
(c) Polhemus
(c) Ascension
The new trend is to use optical tracking (A.R.T, Vicon, Motion Analysis, IO Tracker, Natural Point) by putting inexpensive markers on your body and watching them through special video cameras. This technique has the advantage of being wireless and is becoming cheaper and cheaper, with motion capture solutions starting at 5’000$.
(c) Natural Point
Inertial tracking (XSens) is another very interesting option: it is standalone and very responsive, but has the disadvantage that positional data are drifting very fast (even though a full body capture is greatly improving the stability). Orientation data are pretty stable. But this solution isn’t (yet) ready for a precise head tracking required to generate a correct perspective.
(c) XSens
That’s why some companies take the best of both worlds by combining an inertial tracker with an optical solution to continuously recalibrate the position (Intersense, Worldviz PPT, and yes, the Wiimote !)
Data Gloves aren’t used that much, except when you really need to know the position of each fingers. Immersion’s Cyberglove and 5dt Glove seem to be the most common. A.R.T Fingertracking is a recent product with very precise positional data that works with their optical tracking system.
(c) S. Kuntz
(c) Immersion
Some current research are focusing on markerless tracking, which don’t require the user to put any specific apparatus.
The Inca 6D by Haption, based on the Spidar system, is the only large scale haptics device commercially available. The Haption’s devices compete with SensAble’s Phantom for desktop haptics. Immersion’s CyberGrasp exoskeleton gives force feedback to both your hand and your fingers.
The ART Fingertracking is the one of the few products that adds fingertips sensations, and more researches (CEA List, Laboratory for Intelligent Mechanical Systems) are being conducted to improve the range of available sensations
(c) Immersion
(c) S. Kuntz
The Magnetic Levitation Haptic Interface is ““levitated by magnets”. ”It offers things that other devices just can’t do – the high forces, low friction, low inertia, and six degrees of freedom.”
(c) CEA List
(c) LIMS
How do you walk inside a virtual environment ? This is still a major issue and some answers begin to appear.
The omni-directional treadmill, part of the Cyberwalk project, could be a near-ideal solution if it was affordable.
(c) Virtusphere
The VirtuSphere is already a commercial product and much more affordable (50-100 k$).
Some other research prototypes include the CirculaFloor with moving tiles, and the VR Shoes, both by the Tsukuba university.
(c) Tsukuba University
22:05 Game development, VR Devices, Virtual Reality DIY
Johnny Lee is definitely a genius.. After the Finger Tracking and the Wiimote whiteboard, here’s how with two Wiimotes he’s creating VR games at home !!
(not that we didn’t think about it, but hey.. he actually *did* it =)
If you want to have real 6Dof information from your Wiimote, check out Oliver Kreylos Wiimote projects.
13:16 Augmented Reality, VR Devices
A french lab, who published a paper at Siggraph 2007, is working on a impressive markerless tracking/modeling system, the GrImage Platform:
This architecture is designed for mixed reality applications requiring such dynamic models, tele-immersion for instance. (…)
The acquisition [is] based on standard firewire cameras; the computation, based on a distribution scheme over a cluster of PC and using a recent shape-from-silhouette algorithm which leads to optimally precise 3D models.
17:32 Augmented Reality, VR Devices
Back at IPT/EGVE, Intersense was presenting its MictroTrax and new Wand. The head tracker is really small, and the wand is smaller. It can fit on cheap, lightweight passive stereo glasses without any problem. I did the setup of their installation in no time, it’s all VRPN compatible already (except for the trigger but that should be easy and fast to fix).
They had also a new tracker, the IS-1200 VisTracker. All their trackers use an internal inertial tracker (accelerometers, gyroscopes and magnetometer), which have very fast update rates, but tend to drift. The IS-900 trackers use ultrasound emitters to recalibrate this drift. The VisTracker instead uses a camera that matches Augmented Reality patterns anywhere in your room.
Intersense had sent us the tracker and the associated UMPC so that we could setup Virtools demos.
- The VisTracker, mounted on a UMPC Vaio UX 280 -
- The AR patterns -
- A close-up of the UMPC -
The UMPC is a Sony Vaio UX 280, running on Windows XP which has an Intel CPU at 1.2GHZ with 1Gb of RAM. Virtools runs perfectly on this. The display is really bright. The only problem is the size of the keys! Maybe with a virtual laser keyboard this would be more practical.
I believe there is still some work to do for the tracking to work flawlessly. The inertial tracker drifts quite fast, and it takes a couple of seconds for the camera to recalibrate when if finds an AR pattern. Once it has two in sight it works quite fine excepts that it sometimes loses the patterns every now and then.
With this system you can print your own AR patterns, stick them anywhere in your building, register their position in the software. This allows you to be precisely tracked in a potentially huge surface for a flat fee!
Here’s an official video :
9:37 VR Devices
Intersense is announcing a new tracking device for its IS-900 inertial/ultrasonic tracking system : the MictroTrax.
It’s small, it’s slick, and it has a new Wand 
The new Head Tracker is over 40% smaller than the previous generation. The Head Tracker’s Wireless Transmitter has a clip to attach onto a shirt collar, belt
or anywhere else. It can also fi t easily inside a shirt pocket or an eyewear retainer. The new wand design brings unprecedented comfort, especially during long-term sessions.
From the official PR :
Additional benefits of the new MicroTrax devices include:
23:28 Game, VR Applications
Here are two videos demonstrating interesting (read “fun”) uses of VR. Lightsaber and 3d modelling!
Related article : VR FPS : Atrium Experience
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