MPM chooses Digital Projection for an innovative Cave at CEA Tech

The integrator MPM Equipement uses the E-Vision Laser 10K projector Digital Projection for a temporary installation in a Cave, located in one of the laboratories that manages CEA Tech.

With more than 3.300 M², the laboratory of Cea in the French city of Grenoble -- known as Y.Spot– is an open innovation center used to develop a broad portfolio of energy and health technologies, as well as to spread new technologies for the industry, building a bridge between the worlds of research and business.

Through his work at Y.Spot, that hosts collaborations with industry, plural of pyme, students, architects and designers, CEA Tech (technology branch of France's Atomic and Alternative Energy Commission – Cea) it also provides companies with access to key facilitating technologies, as well as those developed by other operational divisions of this entity.

Like CEA Tech, integration specialist MPM Equipement it also does its job in various sectors, as it started with installations in theaters, concert halls and museums, and then went on to work in conference rooms, meetings and sports venues in the MICE environment.

“We also help customers digitize their offering with new communication tools through Byod (bring your own device) or automation," explains Nicolas Jeanselle, PROJECT Manager of MPM Equipement-. We are proud to be specialists in everything audiovisual and work to make everything work and communicate together. Cave technology (immersive virtual reality environment) it's not particularly our specialty, but this project goes further”.

Sirce Development

The installation, Called Sirce (Smart immersive room for circular vision experiment), was designed by engineer and set designer Frédéric Ravatin, company Creatime, in the form of three truncated pyramids, with a base of 5 M² (variable +/- 10% according to prototypes and space configuration).

Inside this space, the floor and three of the walls serve as 3D embossed screens that can be used to recreate environments and objects, and even host video conferences also in three dimensions.

Although the Cave can accommodate up to twenty-five people, normally used by between five and ten. In it, all visitors are invited to wear the active glasses Xpand 3D to have a feeling of total immersion when stereoscopic content is projected onto the four synchronized and aligned screens.

As Sirce's faces are tilted inwards with an angle of 26 Degrees, significant distortions of perspective in stereoscopy can be induced and exaggerated, making the virtual environment look much bigger than it actually is.

In this way, the user may feel that he looks 'beyond’ of the confines of the Cave, recreating a bigger world, whose dimensions and space still look 'normal’ (a phenomenon known as orthostereoscopy).

Projecting perception

“The project's set designer won the contest for the remodeling of the CEA's Y.Spot, where the Cave is installed," Jeanselle recalls,. The idea was to create a virtual environment in which you could show any medium and content in an immersive way”.

In addition, MPM Equipement had already worked with Frédéric Ravatin on several projects, among them in Europe's largest freshwater aquarium-museum: Aquatis, located in Switzerland.

After a long period of testing, the MPM team deduced that the only method that could be used to compensate for deformations induced by sloping screens was to recreate the path that would make light from the observed object to the viewer's eyes, simulating on screens, to a pixel, where the beam of light should pass if the viewer were actually in that virtual environment.

As Jeanselle points out, “Were, indeed, projecting people's perception”. Like this, for each screen two virtual cameras were placed, located about where the viewer's eyes would be (to some 1,6 m from the ground, in this case); one for the left eye, drawn in red, and another for the right eye, in blue.

Each of the four projection surfaces (left, frontal, right and ground) requires two cameras, which gives a total of eight, grouped into four teams of two. The left and right cameras of each team were separated 6,5 cm (the average distance between the two eyes) and perfectly parallel, no convergence.

“This information is recorded, allowing us to create a synthetic Sirce model on the right scale, because the dimensions and angles taken are recorded with a laser meter. Below, we use the same cameras as if they were projectors, texturing the inner faces of the Cave”, Jeanselle points out.

Once the information is recorded, shipped in real time, what it's used for TouchDesigner of Derivative, five teams E-Vision Laser 10K manufacturer's Digital Projection to project it into the Sirce.

“We needed a low-maintenance unit, capable of supplying 10.000 Lumens, with a very short-range lens that could be on the axle with the center of the Cave," Jeanselle continues.. Laser was also environmentally mandatory, in addition to ensuring low noise and heat generation in the relatively small tent”.

Digital Projection projectors, as this expert says, “met all these criteria and more, at the same time they had a very good price considering their performance and quality. It also provided us with a partner who could accompany us throughout the conceptual phase and beyond”.

For this application we had to feed the video projector with two video streams of 120 hz (a connection mode called Dual Pipe), to allow each unit to switch very quickly based on a precise frequency between two video sources, in this case, left and right eyes.

Solve this issue, added that projectors should be able to handle many different types of 3D, resulted in a complex calibration period for the equipment, as Jeanselle points out.

“It was a long process, but the quality of industrial calibration that was done before receiving the projectors was impressive. There was no discrepancy between each unit, even if they weren't exactly the same lot. In Digital Projection they behaved fantastically throughout the process and lent us the projectors for weeks so that we could test them with the rest of the devices and contents”.

In this sense, Jeanselle recalls that “Stephane Bourdon, sales director of Digital Projection in France, and his team were always available; there were no problems, they sticked to the agreed dates and devoted a lot of effort to pre-sale. simply, we wouldn't have been able to do the job without them”.

Although the last tweaks of the facility had to be postponed due to the continuous interruptions caused by COVID-19, Jeanselle points out that the client was very happy with the project so far.

“If a viewer is in the exact position of the cameras, the illusion is perfect, even in stereoscopy. The experience we've gained in the prototype phase, combined with advanced hardware and software, has allowed us to maintain the highest quality of immersion. Even with half a dozen simultaneous viewers, the effect remains incredibly shocking”.

For Tiana Delhome, director of Hospitality by CEA Y.Spot, “the MPM team has guided us very well in what was a very complex and innovative project, showing great availability and flexibility on many occasions, in addition to meeting all deadlines. We are very happy with the finished device and look forward to benefiting from it for years”.

Other articles on Cea, CEA Tech, Creatime, Derivative, Digital Projection, MPM Equipement, XpanD, Xpand 3D