For the past decade, inventors in different corners of the world have been perfecting 2-D and 3-D open-air displays. Early users — despite the hefty price tags — mainly include doctors, medical researchers and some military organizations.
Displaying an image using conventional projectors requires a nontransparent medium, typically screens, walls or even water. Obviously, air won’t work. Many open-air displays use some sort of mutated air similar to the FogScreen projector from the Helsinki company of the same name. It projects images onto a thin, stable sheet of fog. Others use mirrors and rotating screens to create images with depth.
Here are some of the front-running developments in multidimensional displays:
Heliodisplay: Created by i02 Technology, this 2-D device can project an image onto the air just above it, creating the illusion of a floating 3-D hologram. The Heliodisplay uses a cloud of microscopic particles whose makeup remains a trade secret.
The Heliodisplay creates a particle cloud by flowing air through a heat pump to cool the air below its dew point so it condenses and forms an artificial cloud of micro-droplets held together by surface tension, each between 1 to 10 microns in diameter — too small to be seen by the naked eye. A user of this display can create sharper and brighter images by changing the cloud’s properties.
The company is marketing the Heliodisplay to corporate customers who can use the device as a way to display their company’s logo or as an advertising and promotional tool for exhibitions.
The new M30 model projects a 30-inch floating image just more than 2 feet above the projector, with image refresh rates of up to 30 frames per second with resolution of 640 x 480 pixels. The image is visible at an angle of up to 150 degrees. For $4,000 more, the M30i lets a user adjust an image by moving a hand in the holographic cloud.
Perspecta: This display, from Actuality Systems, lets users view moving objects from any angle. Perspecta Spatial 3-D System v.1.9 has a round rotating white polymer screen that rests on the display server. Moving images float inside a crystal-ball-like structure generated by slices of successive 2-D images, rapidly projected one after another onto the screen, creating an illusion of a 3-D image.
Perspecta, which costs thousands of dollars, streams the images as video with a resolution of 768 x 768 video and a 30-hertz refresh rate. Actuality Systems says that it has military users who are interested in Perspecta’s ability to display 3-D topography.
USC holographic display: The University of Southern California’s Institute for Creative Technologies has developed a 360-degree holographic display that consists of a high-speed video projector, a spinning mirror covered by a holographic diffuser and a specialized processor to decode uniquely rendered video signals transmitted from a computer. The system uses a standard programmable graphics card to render more than 5,000 images of interactive 3-D graphics per second.
Mark III: At the Massachusetts Institute of Technology, a team has focused on creating a 3-D holographic video system that’s compact, ready for market soon and priced in the hundreds of dollars.
Although early versions of the system require specialized hardware, Mark III can process 3-D images using a standard graphics processor so that users can run it on gaming consoles and desktop PCs. Scientists redesigned an acousto-optic modulator, often used in telecommunication systems, to keep the cost down. The modulator, which reproduces interference patterns that encode information about the projected object, directs light from lasers to form palm-size, monochromatic holograms. The MIT team is already at work on a fourth version that can produce larger, full-color images.
Cheoptics360: From Danish companies viZoo and Ramboll Denmark, the Cheoptics360 XL can produce colorful, large and high-quality 3-D videos. The four-sided transparent pyramid can display both computer and film content using a process of surface mirroring and reflections to make images from four video projections appear to float. The device can scale the images to nearly 100 feet across.