Clockwatcher Explains Phelps' Win
ANDREA SEABROOK, host:
Usain Bolt won by just two-tenths of a second, and that was a blowout. Compare that to Michael Phelps' margin of victory earlier. The super swimmer won his record-tying seventh gold medal by a fraction of a fingernail - just one one-hundredth of a second. It was the ultimate photo finish, except even when you study the photos and the NBC video, as I have, it's still tough to tell who came in first.
Earlier today we reached Christophe Berthaud in Beijing. He's the director of Olympic timekeeping for Omega, the official timekeeper of the Games. We asked him to explain the system used to time swimmers.
Mr. CHRISTOPHE BERTHAUD (Director of Olympic Timekeeping, Omega): The athlete, when they arrive at the end of the swimming pool has to exert (unintelligible) pressure on a touchpad. And this contact stops the chronograph.
SEABROOK: So, is it possible that the Serbian who came in second actually just had slightly less pressure in his stroke since he was gliding?
Mr. BERTHAUD: Yes. If you look very carefully at the pictures, you say that Michael was in full action and pushed very hard while the Serbian athlete was gliding in order to get to the pad. So that made the difference.
SEABROOK: But the system actually measures to one one-thousandth of a second.
Mr. BERTHAUD: If you want to give a result with a very good accuracy of a one-hundredth of a second, you have to measure a thousandth of a second. And that's why when it comes to the rounding based on the rules of the regulations of the International Federation, there's no doubt about the hundredth of a second we are giving.
SEABROOK: Did you go back and look at the thousandth of a second reading just to see?
Mr. BERTHAUD: No. The system doesn't allow it. So, it's measured but everything is encrypted.
SEABROOK: But the Serbian team appealed what the touchpad showed.
Mr. BERTHAUD: Yes.
SEABROOK: So, you did go to a video and photo system for a backup.
Mr. BERTHAUD: Yeah, absolutely. We have a backup system that is made of four digital cameras. Each camera takes and records pictures of the arrival line. And we take one hundred pictures per second.
SEABROOK: So, you have no doubt.
Mr. BERTHAUD: No, absolutely no doubt. Something that's also important to understand, because everyone is talking about watching the images on TV. You know that what the human eye perceives is something that lasts at least one-tenth of a second. So, when we are talking about one-hundredth of a second, you know, the human eye cannot perceive it. So, that's why you have to go to very, very accurate system in order to really get (unintelligible) the ranking of (unintelligible).
SEABROOK: What is the system like for measuring sprinters?
Mr. BERTHAUD: In athletics we are using a photo finish camera. So, we take two thousand pictures per second of the…
SEABROOK: Two thousand.
Mr. BERTHAUD: …arrival line.
SEABROOK: Two thousand…
Mr. BERTHAUD: Yes.
SEABROOK: …per second.
Mr. BERTHAUD: Two thousand pictures per second. And then with the computer, we rebuild the image of what happened on the finish line. You can read with a very high precision what is the exact time of each athlete.
SEABROOK: Christophe Berthaud is director of the Omega timekeeping at the Beijing Olympics. Thanks so much for joining us.
Mr. BERTHAUD: Thank you very much.