P016_NELE_OCT11.qxp:Layout 1 6/10/11 13:27 Page 16 Keeping your How technology is improving decisions in a range of sports. By David Boothroyd. port and electronics have been bedfellows for decades – ever since the first live sports broadcasts by radio and TV. And electronics is used Snow in many other ways throughout sport – in training and medical applications, analysis, data recording and so on. But for some sports, electronics and computing have become even more critical in the last decade – by playing a key role in controlling the games as they are played, making match changing decisions on what has happened. It is the result of several areas of electronics coming together – powerful wireless data transmitters and receivers, wireless charging and ever greater chip integration for handling huge amounts of data, allied with computer processing capabilities that can assess and judge complex 3d graphics in extremely short times. All this is vital for use in live sport. A notable success has been Hawk-Eye, now widely used in cricket, tennis, snooker and other sports. Developed at Roke Manor Research in 2001, Hawk- Eye can track the trajectory of a ball and almost immediately show its most likely path. Hawk-Eye has transformed the sports it which it is used, especially cricket and tennis, and whatever some of its human judges think, it is more accurate than any person. It uses the principles of triangulation, taking visual images and timing data provided by at least six high speed video cameras around the area of play. A data store contains a predefined model of the playing area and includes data on the rules of the game. As each frame is sent to the system from the cameras, Hawk-Eye identifies the pixels corresponding to the ball and calculates for each frame the ball’s 3d location by comparing its position using a minimum of two separate cameras simultaneously. A series of frames creates a record of the path the ball has taken. Hence, for tennis, it can report exactly where a ball has landed, with an average error of 3.6mm, according to tests performed by the International Tennis Federation. Hawk-Eye also predicts the future flight path of the ball and where it will interact with any playing area features already programmed into the database – like the wickets in cricket. Cricket was the first sport to use Hawk-Eye, more than a decade ago. Tennis took it up for Grand Slams in 2007. It also creates a graphic image of the ball path and playing area, so information can be shown to commentators, tv audiences and coaching staff virtually in real time. The tracking system is combined with a backend database and archiving for analysing trends and statistics about players, games and so on. Ironically, sports that were seen as old fashioned – like cricket and tennis – have pioneered the use of technology, whereas the world’s leading and 16 11 October 2011 www.newelectronics.co.uk P016_NELE_OCT11.qxp:Layout 1 6/10/11 13:27 Page 17 Cover Story Sport and Technology eye on the ball richest sport – soccer – has been almost passionately anti technology. At least, that was the case until the last World Cup, when an infamous event occurred in the match between England and Germany. Just before half time, England’s Frank Lampard’s shot hit the crossbar and bounced down. TV replays showed immediately, and beyond any doubt, that it had crossed the line by a clear margin, but the goal was not given, potentially influencing the whole match. Similar goal line mistakes have occurred quite regularly. Just using video replays would have a major impact on soccer. A recent study by journalist Tim Long suggests that, in last season’s Premier League matches, errors took place nearly 30% of the time that video replays could help prevent – like penalties given or not, and incorrect offside rulings. Finally, soccer’s governing body FIFA has given in and various technologies for monitoring the goal line are being tested, with the aim of implementing one by 2012. Several companies are participating in trials, including Hawk-Eye, Munich based Cairos, Austrian company Abatec and UK firm Goalminder. They think it’s all over ... With trials completed at FIFA’s Zurich headquarters earlier in 2011, Goalminder has been invited by FIFA to complete further trials. Goalminder’s technology delivers actual images from high speed cameras built into the fabric of the goal posts and cross bar. “We show the actual event, at the point where the ball goal line incident happened,” the company says. “Nothing predicted, no guesswork, just indisputable pictures. All in high quality, 2000frame/s video.” Another developer of goal line technology is Germany’s Fraunhofer Institute, which has developed a soccer ball that uses high speed transmitters to create a triangulation method. This is important for accuracy, according to Erik Jung, of Fraunhofer’s Medical Microsystems Department in Berlin. “Some people think it is a straightforward RFID scenario, where the goal serves as the RFID portal; if the ball passes over the goal line, its position is known. Unfortunately, that would give you little more information than the ball was in the vicinity – accuracy would be about 3m.” Clearly, this is no good. Triangulation, however, can offer an accuracy of centimetres. Four receivers are fitted to the goal frame and the football contains inside it an rf transmitter, which constantly emits a signal. However, fitting the electronics inside the ball is a major challenge. “One technique,” said Jung, “is to mount the electronics on tiny carbon fibre reinforced strings, which can hold the system inside the middle of the ball, so that it is not affected even when the ball undergoes the major distortions that happen when it is kicked.” For various reasons, like cost, Hawk-Eye has been very much for professional events, but a sister company, Hawk-Eye Sensors, is aiming to offer line judging technology to potentially every tennis player. This will use www.newelectronics.co.uk 11 October 2011 17 P016_NELE_OCT11.qxp:Layout 1 6/10/11 13:27 Page 18 Cover Story Sport and Technology need,” says Walter Brennan, founder and managing director of BBG Sports, the Australian developer of Hot Spot. The cameras come from various sources, beginning with ones made in France, then Australia using Israeli detectors and, most recently, from electronics defence contractor Selex Galileo. “I have been talking with them for a couple of years on how to adapt what they have to what we need. The main problem for Hot Spot when there is a very fine edge is that when the bat swings through quickly you get a blurred picture, making the spot difficult to detect.” A related cricket technology is the Snickometer – or Snicko – which is a a ‘tribo-electric’ wire based sensor system placed just below the surface of sound based detection system exploiting the fact that a microphone is the court, which can make line calls accurate to several hundredths of an installed in one of the stumps, making it possible to listen to and view the inch. This could be used on courts at clubs, schools and even personal shape of the recorded soundwave. If the ball has touched the bat, it typically home courts. produces a short sharp sound in synchrony with the image. Other sounds, Tribo-electric energy is the static charge resulting when two objects rub like the ball hitting the pads or the ground, have a more spread out shape on against each other. In Hawk-Eye’s case, the insulation on the wire rubs the waveform. against the insulation on the inner side of the laminate which is sealed onto So far, Snicko has only been used by tv because it is too slow to the wire. The pattern emitted when a tennis ball hits the sensors is very generate the images of the sound wave. However, Brennan has worked clear and discernible – a foot hitting or scraping across a tennis line results closely for some time with Allan Plaskett, the inventor of Snicko, and is in a very different pattern. hoping to combine the two technologies, producing something called Hawk-Eye Sensors includes a hub which Hotsnick. consolidates the sensor wires, an amplifier/filter “Snicko is very good at what it does – if there is which cleans the signals and an a/d converter a sound out there, it generally finds it,” Brennan that connects to software running on a says. “The problem is it doesn’t always tell you standard notebook. This can show the status exactly where that sound comes from.” of the most recent close shot as well as the Combined with Hot Spot, it should be able time since it occurred, and other data. to. Brennan is hoping to provide Hotsnick for In cricket, Hawk-Eye now has a partner – the 2012 season in England. Hot Spot. As its name suggests, it works by “One of the reasons I went down the detecting the heat generated by the friction infrared route was that I felt people would caused when a cricket ball (or potentially believe infrared more than what I call a other objects) makes contact with cartoon,” Brennan says. “There is still a lot something. In cricket, the basic question of conjecture about how accurate Hawk- is: did the ball make contact with the Eye is – admittedly there has been bat or glove, in which case the player is about our system as well. But people out, or did it hit something else like typically accept that when objects the pad or arm, or even just the collide, friction is caused, and with ground, in which case they are not? infrared technology you can see it.” Typically, two cameras on Future advances are possible.