I was planning to comment on the CNN ‘hologram’ effect that they used on election night, and though I see that Tom at Swans on Tea beat me to it (I wave angry fist in the air, shouting, “Curse you!”), I thought I’d comment as well.
As you’ve probably heard already, and heard mocked on The Daily Show, CNN debuted a new technology, in which a correspondent’s image is ‘beamed’ into the CNN studio:
The effect is clearly reminiscent of the very familiar scene in Star Wars:
Though the effect is very cute, it really isn’t a hologram. First, what did CNN do? From their website:
The technology involved placing a subject — in this case Yellin, and later in the evening, musical artist Will.i.am — in the middle of a bright-green circular room inside a large tent at Obama’s Grant Park victory celebration.
The subject was then filmed with 35 high-definition video cameras, barely larger than average point-and-shoot cameras, which ringed the wall of the circular room. The video cameras were 6 inches apart and at eye level, 220 degrees around the subject.
Chuck Hurley, the Washington bureau’s senior producer of video and the staffer tapped by Bohrman to manage the execution of the “hologram,” called it simple chroma-key technology that’s been taken “to the Nth degree.”
“Weathermen have been standing in front of green screens for years now, but that’s [with] one camera,” Hurley said. “Now we can do that times 35, so you can send all the way around the subject.”
Hurley said the tiny cameras “talk” to the New York studio’s cameras, meaning that when a New York camera moves, it “tells” the cameras in the tent which direction it’s moving and keeps the subject in the correct proportions.
Basically, it is a computer-enhanced version of the ‘green screen’ effect that weathermen and movie special effects people have used for years. There was no image projected in front of Wolf Blitzer:
On Tuesday night, Blitzer could only see Yellin on a TV monitor across the studio. Technicians placed a round piece of red laminate on the studio floor where she was “beamed in” so that Blitzer would know where to look.
Actually, this makes it a closer analogy to Star Wars than one might think: in the filming of the prequel trilogy, actors were often required to act and interact with empty space which would later be filled in with special effects!
In any case, CNN really shouldn’t be calling this a hologram, and not even a ‘hologram’, with the word in quotes, as they’ve been doing. In real holography, an ‘image’ is recorded on photographic film of the interference pattern between a reference wave of coherent light and coherent light scattered from the ‘target’. This recorded image is really a recording of the wavefront of the light scattered from the target, which can then be reproduced by reilluminating it. A hologram acts as a sort of ‘virtual window’ to a three-dimensional scene, but doesn’t project an image that can be viewed from all directions in three dimensions.
Is it possible to make a 3-D “Princess Leia”-style hologram? The closest example I can find to date is work reported at USC last year, where a high-speed spinning mirror provides different images to viewers at different locations. This system is also, however, not producing a true hologram (wavefront recording).
I’ll come back to holography in the near future with another ‘basics’ post.
I think my biggest beef with the pseudo-hologram technology, however, is that it serves as a distraction from the actual news without providing any new insight or useful information. I would prefer more money be spent on good field operations and knowledgeable news anchors than on flashy new gizmos.