How a new generation of holographic displays are remixing old technologies with 21st Century applications.
With Abba set to release their first new music in 35 years, clamour for a reunion tour is growing. The pop legends are believed to be hitting the road again in 2019/20 – not in the flesh, but in the form of holograms or ‘Abbatars’.
While the tour is likely follow the circus model of travelling from city to city, there’s no reason why it couldn’t play simultaneously in different parts of the world, as the stars will be virtual.
Abba aren’t alone in using a mix of technologies to trip the light fantastic and thrill fans old and new: Elvis Presley, Tupac Shakur, Roy Orbison, Amy Winehouse, Maria Callas, Michael Jackson, Nat King Cole, and Whitney Houston are among the lost performers who have been resurrected onstage, via technologies such as holography, 3D projectors, and projection mapping.
In the latter case, images are accurately beamed onto moving surfaces, which are sometimes controlled by synchronised robots.
One of the best examples of projection mapping is the short film Box, made by San Francisco robotic design and engineering studio Bot & Dolly in 2013. The technology was subsequently acquired by Google’s parent, Alphabet.
The video, captured entirely in camera, is of a live performance that blends synchronised robotics, animation, and projection mapping to create an immersive world where the real and the digital merge to extraordinary effect.
Projection mapping can be site-specific, too. One recent example is the 2018 celebration of 200 years of the National Museum in Prague, which used the building itself as the screen. Musician Roger Waters’ solo tour of The Wall and his Us & Them show also used some of these technologies.
His former band, rock behemoths Pink Floyd, recreated the iconic prism from The Dark Side of the Moon album cover as a spinning hologram at the 2017 Their Mortal Remains exhibition at the V&A in London.
Meanwhile, a holographic Kate Moss appeared floating inside a glass pyramid at the V&A’s Alexander McQueen retrospective, Savage Beauty, in 2015, and at the show’s New York run in 2011.
The ghostly supermodel who stunned visitors in London and New York was created by projectors, image cropping (to remove framing from the source footage), keystoning, distortion, and angled glass. A larger, life-size version first appeared at a McQueen catwalk show in Paris as far back as 2006, courtesy of VFX company, Glassworks.
But many of the things that we call holograms aren’t, strictly speaking, anything of the sort. A hologram is a physical object that diffracts light into an image – a recording of interference patterns that contains 3D information about an object. The term 'hologram' can refer to both the encoded material and the resulting image from it.
However, the other methods of projecting images described in this article can still be described as ‘holographic’, because they have an optical presence and appear to have spatial/3D quality.
The particular effect used in stage shows, which many assume is a hologram, isn’t a new technology. It’s really an update of a Victorian innovation, the ‘Pepper’s Ghost’ stage illusion. This was perfected in the 1860s by scientific lecturer John H Pepper, based on a concept invented a few years earlier by engineer Henry Dircks.
The illusion relied on the reflective and refractive qualities of glass. At Pepper’s demonstration of the technique, unsuspecting theatre audiences viewed a brightly lit stage through a glass screen. The panel itself was invisible to the audience, because the auditorium was dark and the glass was angled to reflect an offstage actor, allowing him to appear and disappear in front of the audience’s eyes like a ghostly apparition [see image below].
Fast-forward to the present and, by combining existing video with computer animation, computer-controlled projectors, and invisible screens, legendary musicians like Abba, Tupac, Michael Jackson, or Elvis appear to tread the boards again – as 21st Century Pepper’s Ghosts, or phantoms of their former selves.
But the technology is not always associated with bringing the past back to life or reanimating long-lost performers. There’s no reason it can’t be used in real time as a telepresence tool.
In November 2018, students at London’s Imperial College attended the launch of a series of holographic lectures, in a partnership between Imperial’s own Edtech Lab and Toronto-based AHRT Media.
Via the latter’s holographic telepresence displays, people can be beamed into an event from a ‘capture studio’ with near-zero latency, see their fellow panel members, and interact with the audience.
The company’s ARHT Engine enables live streaming of content to one or more ARHT Holographic Displays simultaneously, with multiple playback channels in HD or 4K. Subjects can be prerecorded too, meaning that the technology has strong advertising and retail display potential.
At the launch, speakers appeared life-size onstage at the Imperial College Business School in London, despite being in Los Angeles, New York, and another venue in London. They were able to field questions live from the audience.
Imperial plans to use the technology to deliver lectures from remote speakers throughout the academic year.
Dr David Lefevre, director of the Edtech Lab at the Business School, said: “Introducing hologram technology to the classroom will break down the limitations of traditional teaching by creating an interactive experience that benefits both students and academics.
“Rather than replacing or reducing real-life lectures, the hologram technology will provide greater flexibility for academics by enabling them to continue teaching while travelling, ensuring consistency and quality for students. The technology will also widen the scope for Imperial to invite global leaders and influencers from industry to give talks to students, enriching the learning experience.”
But musicians are getting in on the telepresence act too, with remote live gigs beamed to venues in the form of HD projections onto angled mylar fabric – which reflects any light beamed onto it, but is otherwise invisible to the audience.
Again, the effect is a reworking of the Pepper’s Ghost illusion. The video image is first projected 45 degrees downward onto a floor, which reflects the image back up to the onstage screen. With the transparent sheet also angled, the images appear vertical and perpendicular to the stage.
But not all holographic effects use the Pepper’s Ghost principle. A new generation of programmable displays adds brilliant LEDs to another old technology: propellors. When the propellors spin, they become invisible, creating the illusion of images floating in the air. One company working in this space is Hypervsn.
Meanwhile, a Japanese technology called Holovect claims to use lasers that are capable of “ionising air molecules” to create images that float in the air on “pockets of photon-emitting plasma”. These images can even be touched by human hands – unlike those spinning propellors – say the inventors.
Moving, floating, interactive images in the air – without the need for augmented reality glasses? The technology exists to make this Star Wars / BladeRunner 2049 concept viable, according to its inventors – and in portable devices, too.
However, the Kickstarter-funded project has run into problems, with many backers invoking their right to a refund for non-delivery of a working product.
Just don’t call these technologies holograms: in the case of Holovect (if it exists), they’re volumetric vector images projected into modified air – in other words, projections in space.
Yet somehow, we suspect that ‘hologram’ will always be the preferred term for this type of effect, whether the images are volumetric projections, spun from LEDs, or globe-trotting Abbatars. Take a chance on these.
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