In the original Star Wars, R2D2 projects a holographic video of Princess Leia's plea for help. That was in 1977. But today, three-dimensional projection has moved beyond George Lucas' imagination. Last month, a UK-based video company, Musion, successfully transmitted a holographic projection from an office in London to Berlin.
Unlike Star Wars, however, Musion transmitted a life-sized, interactive holographic image of Musion director Ian O'Connell using an optical illusion used to stun theatre-goers in the 19th century.
The illusion, known as Pepper's Ghost, gave audiences the perception of live actors or objects materialising into a scene on stage. The Victorian theatre used a pane of glass at an angle to the stage to throw a three-dimensional reflection of the actor onto the stage. The effect is the same as when a car driver sees a reflection of the dashboard in the side window.
Musion has taken this principle into the 21st century with its patented Eyeliner 3D Projection System, which was invented by the company's managing director, Uwe Maass, who drew inspiration from the Pepper's Ghost illusion.
The main stumbling block with the Victorian approach was that a large pane of glass was needed to reflect life-size images of the actor. Not only was this unwieldy, but when a really large piece was set at a 45 degree angle it would brake under its own weight. Instead of glass, Musion uses a lightweight polymer foil and a front projection system using a single projector. The image from the projector screen is bounced onto the foil, making it appear three-dimensional. The image is a bit like the reflection you see of yourself in a shop windows.
Musion sees the technology as a way to revolutionise video conferencing, where telepresence suites represent the state of the art. In telepresence, each suite is equipped with three to five high definition displays each requiring 3-6Mbps of bandwidth. Musion requires only a single projector, which bounces a video image through its patented foil set at 45 degrees to a projector screen to create the holographic illusion. The main difference between Musion's system and telepresence systems is that its approach needs only 6-8Mbps.
Musion also uses different cameras to the high definition video cameras used in telepresence suites. Images are transmitted 50 times a second as interlaced frames, where odd frame numbers are transmitted, then even numbers every 1/50 of a second producing moving images at 25 frames per second. O'Connell says this is better for capturing moving images than 1080i, which displays the whole frame 25 times a second.
The quality of the network connection is key to ensure the illusion is realistic, says, O'Connell. "The codecs we use to compress and decompress the video feed requires a glitch-free network line."
The network is run by Masergy, which provided a communications network capable of transporting high-definition images and sound.
Video-conferencing is not the only application. "Most telecoms companies see Musion mostly for use in the boardroom, but we think it can be far more inclusive than that," says O'Connell. "It is bi-directional - both sides interact in real-time, so it could work in education where a teacher can be transmitted to a class of two or three hundred, but by using touch-screen technology, she could home in on any PC for a one to one with a particular student.
"Churches can transmit preachers, prisoners can visit their families in their living rooms, engineers and inventors can collaborate, musicians can appear in nightclubs to launch a new album in 1,000 music stores simultaneously and the possibilities for politicians are obvious.
"What the implications are for dating I dread to think. If you think the internet transformed everything, if you think YouTube and MySpace are great, where will this go?"
This was first published in December 2008