Do people often tell you that you look familiar, or that you look just like someone else they know? Do you believe you have a double — a doppelganger — out in the world? Although many people have their suspicions, it turns out that the odds of anyone having a real-life doppelganger are more than one in a trillion, reports

Queue up the the immortal words of Lloyd Christmas, from the film "Dumb & Dumber" here: So you're saying there's a chance? Well, yes, but the odds are extremely long.

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The figure comes from University of Adelaide researchers, who recently used a database containing anthropometric (face and body) measurements of almost 4,000 individuals to search for duplicate faces. When at least seven facial metrics were used, researchers were unable to locate any matches at all among the study group. Furthermore, when the ante was upped to eight facial metrics, that's when the odds jumped to more than one in a trillion of finding a match.

One might imagine that the odds would be even larger than one in a trillion if more than eight facial metrics were used. Basically, this means that advanced facial metrics can be as accurate as DNA or fingerprinting at identifying someone. In other words, you can forget about blaming your doppelganger in court for any crimes you've committed.

"Until now, using facial anthropometric measurements to convict a suspect of a crime didn't stand up in court because there was no proof that no two faces were the same," explained Teghan Lucas, who conducted the research. "This study has provided overwhelming evidence that facial anthropometric measurements are an effective means for identifying a perpetrator when video or photographic surveillance has captured a crime."

"With what we now know about facial anthropometric measurements, we can measure a suspect's face, compare it to a face captured on video surveillance images and determine if it is the same person," added Professor Maciej Henneberg, co-author of the research.

So this is good news for law enforcement, but bad news for your more nuanced doppelganger fantasies. The researchers are now focusing their efforts on looking at how mathematics can be used to quickly and accurately collect facial anthropometric measurements from video surveillance images.

Of course, this doesn't mean that people can't still be fooled by a close resemblance, a look-alike. In the fallible world of human perception, the doppelganger fantasy can perhaps live on. But in the world of video surveillance and facial identification, with our computers at the helm? There's only one you in that world.

Bryan Nelson ( @@brynelson ) writes about everything from environmental problems here on Earth to big questions in space.

Scientists calculate the odds that you have a real-life doppelganger
Do you sometimes think there exists another 'you' out there who looks exactly like you? Well it's possible, but unlikely, say scientists.