La perception de la profondeur d’une scène 3D passe par plusieurs phénomènes, dont l’un des plus importants est sans doute la vision binoculaire : notre œil gauche ne voit pas exactement la même image que notre œil droit, puisqu’il est légèrement décalé. Le cerveau interprète les différences entre les deux images comme une différence de distance de l’observateur par rapport aux objets observés, ce qui crée l’impression de profondeur ou de relief.
C’est ce phénomène stéréoscopique qui est principalement mis en œuvre dans le cadre du cinéma ou de la télévision en 3D tels que nous les connaissons aujourd’hui. Grâce à ses module d’affichage, Tao Presentations permet de tirer pleinement parti de tels systèmes.
D’autres caractéristiques de l’image participent à l’effet de profondeur :
La projection de la scène 3D en deux dimensions introduit un effet de perspective, qui fait converger les lignes parallèles à l’infini. Cette convergence est un indice fort permettant à l’œil d’estimer la distance, et donc la profondeur 3D.
De cette perspective découlent d’autres indices visuels plus ou moins forts : impression de profondeur due aux objets en mouvement, taille relative de deux objets identiques mais positionnés à une distance différente de l’observateur, disparition des détails dans le lointain...
Mais l’effet qui m’intéresse ici, et qui participe également à la création d’un volume 3D, est le flou de mise au point (ou d'accommodation). Lorsqu’on observe un objet, l’œil fait la mise au point sur cet objet de manière à ce qu’il soit net. En contrepartie, les objets qui sont beaucoup plus éloignés, ou au contraire beaucoup plus proche de nous que l’objet observé apparaissent flous. Cette “profondeur de champ” limitée de l’œil est également fréquemment mise en avant en photographie, pour produire des clichés plus expressifs.
Il y a quelques jours, je suis tombé sur un article (en anglais) qui propose une technique pour simuler cette profondeur de champ en OpenGL. En quelques mots, on génère deux textures :
La première représentent l’image 2D de la scène 3D,
La deuxième est la carte de profondeur (depth map en anglais) qui correspond à cette image. Cette carte est une représentation, en niveaux de gris, de la distance qui sépare l’œil de l’observateur du point observé.
Ensuite on utilise un fragment shader GLSL qui va appliquer sur la première texture (image) un flou plus ou moins important selon la distance donnée par la seconde texture (depth map).
La commande frame_texture_with_depth de Tao Presentations permet d’obtenir facilement les deux textures requises. Voici un exemple qui représente deux boules de billard, la bleue se trouvant plus éloignée de l’observateur que la jaune :
Les textures d’image et de profondeur sont les suivantes :
Les tons de gris affichés dans la moitié droite de l’image représentent fidèlement la profondeur de la scène. Ainsi, un point blanc signifie qu’il n’y a aucun objet visible (c’est la couleur de fond qui est affichée sur l’image de gauche, ici le blanc). Au contraire, un point sombre correspond à un objet très proche de l’observateur. La boule jaune étant plus proche que la bleue, elle apparaît en gris plus foncé sur la depth map.
À partir de ces textures, il est possible d’intégrer une version simplifiée du shader écrit par martinsh pour obtenir l'effet de flou désiré. J’ai choisi de le faire sous la forme d’un module Tao afin de faciliter l’utilisation de l’effet. Ce module s’appelle sans surprise “Profondeur de champ” (Depth of field en anglais). Vous pouvez le télécharger et le tester dès maintenant (il est compatible avec Tao Presentations 1.03) ou bien attendre la prochaine version de Tao pour l’obtenir. Le module définit une fonction dof_frame_texture qui s'utilise comme frame_texture tout en permettant de bénéficier de l'effet de profondeur de champ. La mise au point s'ajuste grâce à quelques variables.
Voici le résultat lorsqu’on fait la mise au point sur la boule jaune :
Vous pouvez consulter la documentation technique du module sur notre site. Elle contient le code source du document Tao Presentations utilisé pour illustrer cet article.
You have activated and downloaded a license file after buying a product from our shop (http://www.taodyne.com) but you don't know what to do with it? Well, here it is a little explanation on how add your license to Tao Presentations...
1) First install of Tao Presentations If you just come to install the Tao Presentations software for the first time, you will need to add your license file into the correct directory. The easiest way to do it is to launch the software. As you don't have already set a license, you should see the following message box :
Then, to add your license file :
Click on "Open the license folder" on the message box
Copy and paste your license in the space provided
Reload Tao Presentations to save changes
2) Add a new license into Tao Presentations If want to add an other license into Tao Presentations (for instance, for a module) :
Open the licenses menu under 'Help'
Click on "Open the license folder" to open the correct folder
Copy and paste your new license in the space provided
A l'occasion du lancement de Tao Presentations, Jean-Pierre Largillet a écrit un article expliquant très bien ce que nous faisons:
Fondée par des anciens de HP et présidée par Chistophe Dinechin, la start-up de l'incubateur Paca-Est lance l'Edition Technique de Tao Presentations. Qualifié de "power point 3D", ce logiciel permet de créer des présentations 3D professionnelles qui donnent une nouvelle dimension à la communication.
Jean-Pierre Largillet nous a vu faire des démonstrations à plusieurs occasions, et partage son enthousiasme pour le produit.
Il fait sensation. Développé par la société Taodyne qu'ont fondée quatre anciens de HP Sophia, il donne un incroyable relief à vos présentations sur tablette ou PC et encore plus sur grand écran. Tao Presentations est en effet dédié à la réalisation d'une façon la plus simple possible de présentations 3D professionnelles. Ce qui lui vaut d'être souvent qualifié de "power point 3D". Une des réalisations faite avec ce nouvel outil avait d'ailleurs fortement impressionné voilà quelques mois les participants des premiers Trophées des directeurs financiers ce la Côte d'Azur.
Web Time Medias est un magazine web donnant des nouvelles de la Côte d'Azur, en particulier dans le domaine économique.
The ISE show in Amsterdam was a big success. The Alioscopy 3D screen on our booth was very effective at stopping people in their track, helping us initiate discussions. The picture was very sharp, and we were able to successfully show combinations of 3D movies and interactive, multilingual contents.
Naked eye interactive 3D: the next big thing in digital signage?
Despite the size of the show, there weren't that many 3D screens. Tao Presentation's interactive 3D that you can see with the naked eye was something new and eye-catching. We had visitors from all over the world, from education to retail to advertising. Many of them told us this is something that the market is waiting for. Clearly, Tao Presentations hits a sweet spot in the emerging 3D market.
New Doremi products explained with Tao Presentations
In addition to our own booth, Tao Presentations had another nice spot on the Doremi space, with a 42' glasses-free Dimenco/Philips screen. It's a very different technology compared to Alioscopy, with very different trade-offs in terms of viewing comfort and image quality.
Doremi told me that they were quite pleased with the effect on visitors, and that the application ran smoothly. It had taken a bit of tuning, but the picture was extremely easy on the eye, despite the surrounding lights. The depth effect was really stunning, animations were smooth. Overall, it worked exactly the way it was supposed to for three days in a row.
I love it when a plan comes together
Everything was not as rosy on our own booth. The show didn't start too well for us. The day before the show, we sent our keyboard and mouse to storage by mistake, so we couldn't start our computers. I quickly went to the local MediaMarkt to buy replacements, but I couldn't return on time (the show floor closes at 6PM sharp, excuses not accepted).
The first day of the show, when I connected the new keyboard, our primary demo machine refused to boot up. Windows complained that I had tried to change the hardware, then refused to boot, then offered me a "repair" option which I couldn't activate because it wouldn't recognize my new wireless keyboard and mouse. It took a couple of hours before I was able to have a demo running. Tons of stress, fiddling with graphic cards setup, re-seating connectors. It turns out the root cause was the front USB ports, which seem to be dead.
We had backups, of course, but they were laptops with more limited graphics capabilities. One of them,which I had used at the Startup Week-end in Nice, also has a weak HDMI connector, with a lot of noise in the picture. Noise is bad enough in 2D, it's nearly unbearable in 3D. We started using our Mac laptop on the third day of the show, in addition to the main PC, when it became very clear that running on Macs and Linux as well as PCs was a big selling point. Also, we discovered during that show that the AMD graphic card in our newest demo PC is very fast for a single 3D application, but becomes sluggish when two of them run simultaneously. The problem seems specific to that card, we didn't observe it on systems equipped with Nvidia cards.
At the convergence of 3D and interactivity
On the end of the first day, before I was really done with repairing the whole setup, we had a visit from a journalist. This gave us a nice opportunity to explain what we are doing.
Of course, we had the usual "demo effect". I was trying to speak holding the mike with one hand and using keyboard and mouse with the other. It worked most of the time, except for that one moment where I sent the "Google" page spinning wildly and then would change pages a bit randomly trying to get back on track. Lesson learned. This was practically the last "glitch" of the show. From then on, things were much smoother
3D works, with or without glasses...
During the second and third days, our systems worked flawlessly and practically without interruption. Of course, I couldn't resist tweaking the demo here and there (yes, I know I shouldn't do that).
We had a number of visitors from all over the world: Korea, Japan, Russia, United States, Israel, Egypt, Sweden, Belgium, Netherlands, Italy, France, to name a few. A number of industries were also represented, from 3D hardware manufacturers to contents providers and event organizers.
Overall, the reaction was quite positive. Many visitors commented that our product addressed a real market need. And indeed, we were at the convergence of the two big trends on the show. The first trend was 3D, with 3D screens everywhere, including big 3D video walls from Philips (without glasses) or Hyundai (with passive glasses). The second trend was interactivity, with multitouch tables (Samsung, Philips), video sensors (Fraunhofer institute), touch tablets (almost everybody). But the combination of the two was hard to find. The only other interactive 3D application I saw was a demo for 3Di screens, and it was much more limited in its capabilities than Tao Presentations.
Off-site meetings
We also had very interesting after-hours meetings, notably with manufacturers of 3D screens. Amsterdam is really a beautiful place, with amazing canals, impressive architecture, and cafes all over the place. That being said, the weather was against us. At -10°C, you can call this "chilly" (that same week saw snow in Nice and the south of France).
Overall, the three days were exhilarating, exhausting but also wildly productive. See you next year!
We arrived at the Amsterdam RAI for Integrated Systems Europe 2012. The mess on the show floor the day before the show is really impressive. Hard to believe that in a few hours, everything will be clean, nice and tidy!
Meanwhile, I'm worrying about Taodyne. We launch Tao Presentations at this event. Will our equipment hold up? How will we compare to all the big names around us? Will our software hold during the show? Will the web site be ready (at that point in time, we are still fighting some issues with it)?
