Hold my Pimms! Wimbledon turns to tech for line-ball calls The All England Lawn Tennis Club, organizer of the famed Wimbledon tennis tournament, will make line-ball calls with machines instead of human in 2025. The club on Wednesday revealed that Live Electronic Line Calling (Live ELC) tech “will be adopted at The Championships from 2025: and trusted to make “‘out’ and ‘fault’ calls …
"It seems like a backroom deal all about money"
I'm confused about this whole situation. I don't know any of the figures involved but that won't stop me guessing. My guess is that installing and using this technology costs a lot more than it costs to hire an umpire. I'm betting that even if running costs are slightly lower than an umpire's hourly wage (which I doubt) they will never recoup the massive initial costs. The only thing that makes sense to me here are the two words in Sony's blurb: "broadcast enhancements". If this tech allows broadcasters to show hyper-accurate-hi-def-wizz-bang animations of the ball's path then Wimbledon might be able to justify increasing TV licensing costs. It's either that or Sony has compromising photographs of the Wimbledon CEO.
Well, it's not replacing the umpire. It's replacing somewhere between six and nine line judges per court. The umpire is still there.
But no, it's not entirely about the money, ELC probably does cost more than humans indeed. Tournaments are going to ELC because it is substantially more accurate than humans, and players overwhelmingly like it because it removes what feels to them like a subjective, possibly-biased part of the game. They can just accept the 'objective' automated call and move on. Even if they think the robot maybe got it wrong, they don't feel like the robot might be unusually poor at its job or biased against them, because to them it feels like a robot. (There are actually quite a few humans behind the scenes in a typical ELC deployment, but the players don't see them standing on the court yelling "OUT", so it's not the same).
It's a bit late to get up in arms about this, since two slams (Australian and US Opens) and most other high-level tournaments already went to all-ELC anyway. So far just about nobody thinks it made things worse.
There *is* a money angle, but it's not the one you think: it's all about gambling, like everything in sports lately. See https://www.theverge.com/c/24225103/tennis-ai-electronic-line-calling-hawk-eye-sports-betting-gambling for a very deep and somewhat fascinating dive on that.
Wimbledon uses just shy of 300 line umpires, the BBC version of this story says that they make up to £200 per day plus expenses, and the Championship plus qualifying lasts for 18 days, so my back of a ripped up beermat calculation makes that around a million quid.
And they already have Hawk-Eye installed on all the courts to deal with the line-call challenges, so this is more of an upgrade than a fresh install.
I am gonna guess that Live ELC will cost them more than the current 'non-live' ELC, but if my million guestimate is anywhere near the true figure that can be saved by getting rid of the line umpires...
Oh my goodness that one in the video is close. I don't know if it actually *slides* a full 10cm though. It looks like it descends into the (artificial) grass and compresses before sliding (a bit) and then bouncing up out of the grass.Really interesting to see it all in slow-motion. However, that is *not* a Hawkeye camera running at 300fps - see the numbers below. That camera has got a much higher frame rate - I'm guessing well over 1,000fps, maybe up to 10,000fps.
Just doing some example numbers on this one: A service ball travels at 130mph = 209,205m/hr. That's 3,487m/minute = 58.11m/s.
The centre serviceline is 5cm (0.05m) wide (Rule 1, ITF Rules of Tennis - https://www.itftennis.com/media/7221/2024-rules-of-tennis-english.pdf). So at 130mph, the ball will cross the width of the centre serviceline in 0.05/58.11 seconds = 0.00086 seconds (well, slightly more than that - the ball is travelling at an angle to the line).
300 fps (for the Hawkeye cameras) is one frame every 0.0033 seconds (and they don't say how long it takes to capture each frame). That's almost four (0.0033/0.00086 = 3.88) times slower than the period taken for the ball to cross the line.
So what are the Hawkeye line cameras actually capturing? It doesn't seem like it will be an image of the exact moment the ball touches the line - at that kind of frame rate/capture speed, it will be more of a blur.l
That's not how Hawkeye works, it's not trying to capture the split second of impact in a single frame from a single camera. It captures the entire flight of the ball (and the movements of the players) using multiple cameras, and determines from that exactly where the ball landed.
AFAIK, every test they've run has come out with ELC systems performing substantially better than humans. They are not perfect - Hawkeye's claimed margin of error is 2.2mm, independent researchers say it can sometimes be up to 10mm off - but humans are substantially *less* perfect. The numbers you figured out apply just as well to an extremely fallible human trying to see where the same 130mph serve landed from several feet away, with two eyes and one shot at it. They absolutely don't always get it right. Certainly not when it's within 10mm of the back of the line.
Nice numbering!
"So what are the Hawkeye line cameras actually capturing? It doesn't seem like it will be an image of the exact moment the ball touches the line"
I don't think it makes a decision based on analysis of any single frame. As you point out, the frame rate isn't fast enough for that. I think it takes multiple images and generates a model of the flight path to interpolate where it contacted the ground. I suspect the cricket version does the same, but instead of interpolating, it forward predicts where the ball would have gone if it hadn't hit the batter.
I also suspect that the system needs a fair bit of careful setting up and calibration so it knows where the lines are, as well as where the actual ground (ie the tips of the blades of grass) are. I once spoke to someone who used to work for hawkeye and they said that the actual method is very commercially sensitive.
Yes - I agree that it must be a 3D flight path model. There presumably won't be any sudden changes during the journey, which will make that bit relatively easy.
Once the relative position of all of the cameras is known and mapped (e.g. self-calibrate using lasers for exact positions), the positions of the lines can then be mapped (there will be small variations in court dimensions/line positions).
With that done, you then have the court markers in a 3D volume against which you can map ball movement.
Presumably flight path modelling just requires identification of the position of the centre of the ball (multiple cameras covering multiple planes, cross-reference obtained data), and then fit the obtained data against a suitable model.
With mapped ball and surface characteristics, it should then be possible to determine whether a ball will touch a particular line.
Just need to reluably do all that in a fraction of a second with some fault tolerance/error correction, and on robust kit. Simples! ;)
It does now raise the issue of what constitutes the actual court - is it the model that hawkeye uses, or the actual line on the ground? Given that the line model can be perfectly straight with extreme precision (if not accuracy) but a line painted on the ground will never be perfectly straight (it has to manage going over pesky blades of grass that won't line up for instance).
It's a little like how running systems for professional swimming are more precise than it is possible to build a pool. ie adjacent lanes could be different lengths by more than the precision of the timing system.
Good question - given that precision is the key thing here, that's a potentially big issue. I'm wondering if e.g. they have got some kit (for example, a calibration/mapping device that can trundle along the court lines and gather relevant data) to ensure that court markings are precise, or at least so that they can include the exact position of all markings in the mapped "virtual court".
I mean, we already know what the implementation is. Wimbledon has had it for years, it has just used a challenge system rather than using the ELC for all initial calls. Many other tournaments already use ELC for all calls, including the US and Australian Opens. There's nothing terribly novel here, it's just another tournament joining the list, albeit a big one.
No. In the many tournaments that already do this, the player can ask for the video to be played, just so they can watch a reconstructed ball hit or not hit a reconstructed line in the way the electronic voice based on the same reconstruction already said it did. They quite often do so, and you can analyze the psychology behind that at your leisure! (Sometimes they just do it to buy ten seconds to get their breath back).
The other shoe will drop once all the former linesmen are too old and out of practice to come back to work, and there are no replacements trained any more - hello, lock in to the friendly electronic line-calling provider. What's your estimate on Sony's level of greed here? 20% annual price increases in perpetuity, maybe?
A few remarks here:
a) Although it seems to have never been formally asserted, and has nothing to do with technology, the pandemic era saw at least the end of one of the most outrageous traditions in tennis, Wimbledon or not : ball kids being required to bring their towel to the players between points. Had always make me feel rather uncomfortable. And, as @Essuu stated it, I was half expecting some kind of robotic arm to replace them!
b) I agree with @AdamWill that this move is probably motivated by the huge expansion of sport betting, among other reasons. These bets in turn having a very nasty side effect: any player considered as a favorite and losing, has his social media accounts instantly flooded by hate messages (and of course each of one is on insta and so on). Money in sport corrupts everything - like in any other place.
c) As noted here, most players seem to welcome a kind of electronic ruling vs human one. But there are some exceptions: on the female side of the game, Jelena Ostapenko (RG 2017 winner) famously (and vocally) distrusts the HE system.
It isn't a judgment call, either it is in or it is out. What would be interesting would be if someday they could make judgment calls like holding or pass interference in American football. No longer would fans be able to claim the officials are biased against their team. That's so ingrained in the culture of every team sport that I think fans might reject it, because it would be the end of "we would have won that game if the refs hadn't screwed us!"
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