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For quite a while now there has been talk about 3D screens being used for digital signage, but where are they? Most screen manufacturers, including Sony, NEC, LG and Toshiba, have introduced autostereoscopic screens at one point or another, but many have quit their 3D quest. 

Three-dimensional content for DOOH needs to be autosteroscopic or multiscopic, that is, glasses-free. Fortunately companies such as Alioscopy, Philips, 3D International (3Di), Exceptional 3D and Magnetic 3D, to name but a few, are still continuing the race towards 'images that jump from the screen'.

The take-up of 3D for DOOH has been slow. One of its main problems is the lack of perceived image quality, which is partly due to the content, and partly due to the screen and the type of technology it uses.

"Quality is essential, not because people request it, but because 3D addresses the brain and if you don't have a minimum level of quality the brain will not be immersed; it will realise there are no real 3D objects in front of it and won't believe the content," says Gilles Marcellier, Alioscopy's EMEA sales director. "If you want to have a sustainable emotion you need to have a high brain acceptance." Marcellier highlights new developments in image processing convergence technologies that will allow 2D images to become good quality 3D, which can give a major push for 3D stereoscopic displays.

French company Alioscopy, founded in 1999 by Pierre Allio, manufactures its screens and develops its software in Paris. It has a portfolio of patents covering all aspects of this groundbreaking 3D technology and it distributes globally. Alioscopy's technology is based on the combination of an image multiplexing algorithm – the software – and a high-precision array of lenses very accurately positioned on top of the LCD panel – the hardware. The lenses are lenticular and they have an accuracy of ten nanometres.

"The main use for autostereoscopic 3D technology in the DOOH market would be any applications where the use of 3D will provide added value," explains Marcellier. "For instance, when a 3D movie is launched, using glasses-less screens in cinemas to promote the trailers can give cinema-goers a real taster. But this doesn't end here. Around movies there is a world of merchandising that might want to jump on the 3D wagon and advertise their products.

"An example of this was Haribo jelly sweets, which launched a printed 3D campaign to coincide with the premier of Avatar. Printing company Hive created a series of 3D lenticular images from Avatar and they were inserted into Haribo sweet bags. This could be done in full motion on our screens."

Alioscopy's screens come in two multi-viewing choices: five or eight viewpoints. "Whether you choose the former or the latter would depend on the application and it is always a trade-off between the viewer's freedom of movement and image quality," explains Marcellier. Five viewpoints will give better image quality, but the viewer has to be in the right position, or sweet spot, to get the full effect. Screens positioned where the time of viewing is less and the spectator can easily move around to find the right angle are the most suitable for DOOH applications. Eight viewpoints are best for environments where the viewer is more static, like the screens used in healthcare.

But the number of viewpoints on the perceived quality is only one component. The software and technology used on the screen also play a major role. Marcellier says: "Technically there are three main 3D technologies: holographic, lenticular and parallax barrier. Lenticular, which is what Alioscopy uses, preserves the quality and colours of the screen. Parallax creates a grid in front of the screen and a series of precision slits allows each eye to see a different set of pixels. This eats away the brightness of the image. This is why the better the screen technology, the better the 3D. Quad HD, for instance, will benefit this market enormously."

German company 3Di uses parallax barrier technology. The screens come with a multilayer optical element technology called Chromatic Light Deflector with special features in brightness, colour truth and 3D effect, to compensate on the quality front.

For those interested in 3D, International 3D Innovation Day will be held in Berlin, Germany on September 4th. Curated by the 3D Innovation Center Berlin in association with Medienboard, the conference will discuss current trends and the latest developments in 3D technology.