If the ball goes out of bounds in say, a soccer game, it’s up to the referees to call the violation. But in a high-level curling match, the stones are somewhat self-policing—thanks to the red and green lights atop each one.

如果一个球，比如足球，出界了，那么裁判会进行判罚。但是在高水平的冰壶比赛中，冰壶本身就具有一定的自我裁定功能-这要归功于每个冰壶上方的红灯和绿灯。

As long as the curler releases the stone before the front of it crosses the first red line (the “hog line”), the lights will stay green, and play will continue. If you see the red lights come on, that means the curler kept their hand on the handle too long, committing a hog line violation. The shot is disqualified, and the stone is quickly removed so it doesn’t interfere with other stones on the curling sheet.

当冰壶运动员在冰壶正面越过首道红线时（“栏线”）松开冰壶，冰壶上的绿灯将保持亮起，比赛将继续进行。如果冰壶上的红灯在此时亮起，则表示冰壶运动员的手在冰壶手柄上放置的时间过长，并从而违反了栏线规则。这次投掷将被取消资格，冰壶将会被从冰面上取走，以免其干扰到冰面上的其他冰壶。

The detection system, called “Eye on the Hog,” dates back to the late 1990s, when University of Saskatchewan engineering professor Eric Salt suggested that some of his advanced electrical engineering students invent one for a class project. With his help, they did, and Canadian engineering company Startco modified their design and brought it to market. The Canadian Curling Association soon adopted it for official use, and its popularity grew from there.

探测系统，也被称为“栏眼”（Eye on the Hog）可以追溯至20世纪90年代。当时，萨斯喀彻温大学的工程学教授Eric Salt 建议学习高级电路工程的一些学生为这项经典运动发明一个探测系统。在他的帮助下，这些学生们发明了出来。一家叫做Startco的加拿大电子公司对他们的设计进行了修改并将其推向了市场。加拿大冰壶协会很快就将其用于正式场合，而探测系统也就从此而变得流行起来。

Basically, there’s a magnetic strip installed beneath the ice slightly behind the hog line—or, more specifically, the length of one stone’s radius before the edge of the hog line. Inside the stone is an electrical circuit whose current is affected when you’re touching the handle. If you’re still touching the handle when the stone crosses the in-ice magnet, it’ll set off the battery-operated red LEDs. Release the handle before the stone reaches the magnet and the green lights will flash until the stone gets there. At that moment, the flashing will switch to a steady green to indicate that the release was valid.

总体而言，在栏线稍微靠后的冰面-或者（更加准确表示的话，就是栏线边沿前，冰壶半径长度的冰面）下方安装有一个磁条。冰壶里面装有一个电路，当你触碰到手柄时，电路中的电流会受到影响。如果当冰壶穿过装有磁条的冰面时，你的手还在触碰手柄，那么冰壶表面带有电池的红色LED灯就会亮起。在石头快要碰到磁条时松开把手，绿灯将会闪烁，直到冰壶到达栏线。这时，绿灯将从闪烁变为常亮，以代表冰壶的投掷有效。

This system also explains why the player releasing (“delivering”) the stone doesn’t wear a glove on their delivery hand: They’re not allowed to, since gloves inhibit the touch sensor.

该系统也说明了为什么冰壶投球手推球的那只手不戴手套：比赛规定冰壶投球手推球的那只手不能戴手套，这是因为手套会抑制触摸传感器。

Due to the high caliber of Olympic curlers, hog line violations aren’t common in Olympic curling matches—so you don’t often get to see the red lights in action. But they came in handy when Italy’s Stefania Constantini kept her hand on the handle just a bit too long during a mixed doubles match against Norway on February 3. (Italy still won.)

因为奥运会的冰壶选手都具有良好的素质，所以违反栏线规定在奥运比赛中并不常见-所以你不会经常看见红灯亮起。但是，在2月3日，意大利对挪威的混双冰壶比赛中，意大利选手Stefania Constantini的手在冰壶手柄上的时间只是稍微延长了一点，冰壶上的红灯就亮起了。（最后还是意大利队获胜了。）

文章来源：Mental Floss

编辑&翻译：上海译锐翻译