Holograms: Virtually Real
technology by cable network CNN. Show anchor Wolf Blitzer told the world it was something that had never been done on TV. Moments later, a seemingly three-dimensional correspondent appeared in the studio.
They may look like holograms, but images created with viZoo's Free Format technology are not-even the company says so.
The next day, AV pros and academics united on message boards, flouting the feat as nothing more than camera tricks. "Sorry to disappoint you but that, along with a host of other tricks, was not a hologram," says Martin Richardson, chair of Modern Holography at De Montfort University in Leicester, U.K, in an interview for Pro AV. "There are many videos online [claiming] to be holograms, such as the CNN trick, and are in fact hoax holograms. Real holograms are truly three-dimensional images made with lasers."
In fact, the technique used by CNN was more like tomography–or imaging by sections. Tomography can produce 3D images computed using a series of angles of the same image. Years in the making, the CNN effect was created by 35 high-definition cameras that ringed a round, blue-screen tent in Chicago. The cameras were 6 inches apart and at eye level, 220 degrees around the correspondent. The technology was developed by Israeli-based SportVU as a new way of filming soccer games.
The setup included virtual reality tracking pedestals and a jib made by Shotoku of Japan. The pedestals calculated the camera's position and sent the information from multiple cameras to a telemetry tracking system. According to Shotoku, every moving part of its system, from the wheels of the pedestals to the pan and tilt of the heads, was tracked and sent to a computer that mimicked the correspondent's behavior. The data was processed by a Vizrt virtual reality system and piped through a fiber-optic network to the CNN studio in New York.
"What CNN showed and inaccurately called a hologram was actually a technique commonly referred to as 'augmented reality,'?" explains Olav Christensen, technical director for advertising film company viZoo of Copenhagen. "It is a clever system of cameras working in synch over distance. Wolf Blitzer did not see what the audience saw on their TVs. The image that appeared in front of him was superimposed on the live feed. So what you have is a set of cameras in the studio where Wolf was, with the same relative distance to a specific space as in the tent where the correspondent was standing. If the cameras in the studio moved or changed their angle, the cameras in the tent would move with them. If you put those two feeds together, you will see the same angle on both sets."
So, What is a Hologram?
As Richardson notes, holograms cannot be created with a camera lens. Holograms are 3D images made by laser light. In essence, it is the recording and playback of 3D images using lasers in a highly controlled setting to store the information from three-dimensional objects within a two-dimensional plane.
But can a hologram behave in the same way as CNN's tomogram?
"One day, yes," says Richardson. "But holography alludes to the replication of wavefronts rather than electronic imaging. Although there are electronic digital developments that promise to yield a hybrid system, these are some years away. If we remove the screen from the CNN hoax hologram and replace it with a super fine mist of water vapor, one could theoretically project a holographic image into the mist." Such technology is in development at the University of Tokyo.
Christensen agrees, "A true hologram could not behave that way at this time. It really depends on how far you would go in your interpretation of the word 'hologram.'?"
viZoo makes volumetric displays that appear like holograms. The images can be interactive and live. "However, my own definition of a true hologram is actually very simple," Christensen says. "If you can stick your hand through it without disrupting any screen, screen material, or the image itself, I would define that as a true hologram. This does not exist yet. We are working on it though."
Christensen's firm viZoo has made its name offering lifelike advertising content using its patented Free Format and Cheoptics360 products. "We never call it hologram, because it's not," he says. "Free Format is a very fine light-conducting acrylic material mesh suspended beyond the spectators' field of vision. We then produce content in a way to erase the background. This image is then projected back on our screen material. When the spectator looks at our two-dimensional cutout image and the corresponding reality behind it through the invisible screen material, you have an instant optical illusion."
That is not to say that interacting with a virtual image is impossible. The closest the AV market has come to an R2D2-Princess Leia moment is immersive high-definition telepresence. Digital Video Enterprises (DVE) of Irvine, Calif., was founded in 1995 and reportedly holds the largest patent base in telepresence technology. Co-founders Jeff Machtig and Dr. Steve McNelley have developed group telepresence applications such as their Telepresence Stage, a portable presentation system capable of life-size presenters and virtual objects.
"The developers of stage craft have used the word 'hologram' in a way that has misled the industry," says Machtig, whose professional background includes special effects and broadcast. DVE's products provide what they call an "aerial image" used in augmented reality, i.e., a virtual person in a real world space.
In short, while CNN's "hologram" was a technological feat of broadcast engineering, the world will have to wait a little longer before scientists can create a truly live, interactive holographic image.
Linda Seid Frembes is a contributing editor to Pro AV.