Holograms that can interact with humans may sound like the stuff of galaxies far, far away but scientists say such technology could soon be available on our own planet.
Researchers at the University of Sussex have created a device that projects floating 3D images like those familiar to fans of the Star Wars films.
“I believe that in the future, such displays will allow us to interact with our family and friends as if they are close by, so you can see, touch and hear them,” said Ryuji Hirayama, who helped make the hi-tech gadget.
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What is a hologram?
“Like a photograph, a hologram is a permanent record of the light reflected off an object,” says the Explain that Stuff site.
Holograms are created by splitting a beam of light, usually a laser, so that part of it bounces off an object before hitting a recording medium such as photographic film. The other part of the beam shines directly on the film, which then records the difference between the two parts.
Interference between the two beams as they intersect is then used to create a three-dimensional representation of the original object, explains tech news site Lifewire.
Holograms can be seen with the naked eye and can be viewed from multiple angles. The viewer’s perspective when looking at a hologram determines what they see, just as with a real-life 3D object.
However, the technology currently available to produce holograms is very limited - creating moving images is difficult, and the size, viewing angle, frame rate and depth of the projected image are all restricted.
What have scientists invented?
The Sussex University scientists have created objects that appear to be suspended in thin air by using a 3D field of ultrasound waves to float a polystyrene bead and then whip it about at high speed to trace the shape it makes.
The 2mm bead can trace out the shape of an object in less than 0.1 of a second, meaning the brain doesn’t see the bead - only the shape it sketches out. The object’s colours come from LEDs built into the display that shine light on the fast-moving bead.
In fact, these images are not technically holograms but rather “volumetric displays”, which means they are free of the limitations of holograms. They can be viewed from any angle and even be made to appear to speak, the researchers explain in a paper published in Nature journal.
And manipulation of the sound field can allow users to interact with the images and even feel them.
The objects the researchers can create can currently only exist inside a 10cm-wide cube of air, but future displays using multiple beads at once could create much larger shapes.
Euan Freeman, a human-computer interaction researcher at the University of Glasgow, told The Guardian that the technology may be a taste of the future.
“With this technology, you could reach out and feel the digital images shown in the display,” he said. “The ultrasound waves move through the air to create precise patterns against your hands. This allows multimedia experiences where the objects you feel are just as rich and dynamic as the objects you see in the display.”
What are the alternatives?
Computer Generated Imagery (CGI) is often used in films to create objects that are looking ever more life-like.
And CGI objects are no longer confined to the 2D screen. In 2012, a computer-generated image of rapper Tupac Shakur, who was killed in 1996, appeared onstage alongside Snoop Dogg at California’s Coachella music festival.
The trick was pulled off using an angled piece of glass placed on the stage that reflected the CGI from a projector image shining onto another screen that was invisible to the audience.
In a more recent example of hi-tech “magic”, Argentinian football club Estudiantes de La Plata celebrated the opening of their new stadium this week by unleashing a giant CGI lion into the grounds.
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