CNN reporter Jessica Yellin said she was following in the tradition of Princess Leia. (CNN)

CNN made waves on Tuesday night by incorporating three-dimensional holograms into its coverage of the U.S. election. The only problem was, they weren't really holograms.

"They were quite sophisticated, no doubt," said Hans Jürgen Kreuzer, a professor of theoretical physics at Dalhousie University and an expert on holography who watched the 3-D interviews. "But I immediately said to my wife that I don't think it has anything to do with holograms."

At about 7 p.m. ET, reporter Jessica Yellin, who was in Chicago, spoke with New York-based anchor Wolf Blitzer live "via hologram," CNN said.

Yellin appeared somewhat fuzzy and her image, apparently projected a few feet in front of Blitzer, appeared to glow around the edges. "You're a terrific hologram," Blitzer said to her.

"It's like I follow the tradition of Princess Leia," she said, referring to the Star Wars character.

Yellin explained that her image was being filmed in Chicago by 35 high-definition cameras set in a ring inside a special tent, which were processed and synchronized by 20 computers to the cameras in the New York studio.

The network, which made use of three-dimensional imaging technology produced by Norway-based Vizrt and Israel-based SportVu, billed the interview as a first for television. CNN also aired a second "hologram" interview between anchor Anderson Cooper and rapper Will.I.Am, who was also in Chicago.

The CNN anchors were not really speaking to three-dimensional projected images, but rather empty space, Kreuzer said. The images were simply added to what viewers saw on their screens at home, in much the same way computer-generated special effects are added to movies.

Kreuzer said the images were tomograms, which are images that are captured from all sides, reconstructed by computers, then displayed on screen.

Holograms, on the other hand, are projected into space.

CNN officials could not be reached for comment.

Kreuzer said technology is not far from being able to produce what CNN had tried to do, although capturing and projecting holograms of big objects like people is still a ways off.

Holographic images are generally captured and projected using coherent light such as lasers. A laser would need to be more than six feet in diameter to capture a person's image, which Kreuzer said is impossible because such a light would be blinding.

It may soon be possible to capture and project large objects using other sources of coherent light, such as light-emitting diodes. LEDs are considerably cheaper and safer than lasers, Kreuzer said.

"There will be some rapid development now because of the cheapness of these LEDs," he said. "You can use a thousand if you want."