Slashdot Mirror
Casting Doubt On the Hawkeye Ball-Calling System
Human judgment by referees is increasingly being supplemented (and sometimes overridden) by computerized observation systems. nuke-alwin writes "It is obvious that any model is only as accurate as the data in it, and technologies such as Hawkeye can never remove all doubt about the position of a ball. Wimbledon appears to accept the Hawkeye prediction as absolute, but researchers at Cardiff University will soon publish a paper disputing the accuracy of the system."
Why not use a radio transmitter in the tennis ball (or soccer ball or whatever) to record its exact position? I am certain this has been discussed and I wouldn't be surprised if it's already in use. The article's "Hawkeye" just works by optical analysis.
The decision of which system to use: human, computer, human with computer check, computer with human check, committee vote, or what-not should be based on which has the lowest uncorrected error rate within limited time constraints.
This assumes there is another method, such as post-analysis of videotape, that can find almost all uncorrected errors or at least give some good indication of the uncorrected error rate.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
And ultra-accurate GPS like system that tracks the position of balls in nanosecond detail. They can call it Your Object Universal Remote Movement Observance Mechanism, or YOUR MOM for short.
If you leave the store parking lot, one of the wheels locks.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Can this be applied to something useful. You know besides whether or not someone was out in a game of tennis?
This is a tennis topic.
The score should be 15-love not 8-love you insolent clod!
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
major league base ball umpires union does not like systems like this and systems like that are not 100% also there stuff that is hard to make calls that can be 100% done by a bot.
http://query.nytimes.com/gst/fullpage.html?res=9406E6DE1F39F933A15754C0A9649C8B63
http://query.nytimes.com/gst/fullpage.html?res=9D00E1D61130F933A1575AC0A9649C8B63
http://findarticles.com/p/articles/mi_m1208/is_24_227/ai_103378465
http://en.wikipedia.org/wiki/QuesTec
They're reproducing stuff that's already known. Yes, Hawkeye can be inaccurate. However, it's MORE accurate than linesmen and certainly the chair umpire. That's why it's used as the definitive word.
I'd certainly prefer it to be used otherwise - the best way would be to give the chair umpire the information from HawkEye and then let him decide whether to use it or not at any given time, properly educated about the types of errors the machine can make - but that wouldn't be as flashy, would it. So the advertisers wouldn't go for it.
Hawkeye and the like deliver a consistent result. It matters not at all if the ball is in by two Centimetres but is called out, provided that error is consistent throughtout the match.
If both players, or teams, are playing by the same margin of error, the contest is fair.
In cricket for instance, I would accept the computers call over umpires any day of the week!
I've seen in Hockey and Football broadcasts the ability to track the ball or puck realtime thru some system inside the playing piece (puck or football.) It seems to work pretty decent to me.
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
As someone formerly involved in naval aviation, let me just say that the headline had me thoroughly confused for a few seconds. I thought the current fresnel lens optical systems were just fine.
It's hard to believe that's how Micronians are made. Why don't we see it right now by having you both kiss one another?
Nobody believes that Hawkeye is perfect, but the fact is that something has to have the last word on line calls, otherwise you can just look forward to hours of bickering.
Hawkeye gets that honor because it's the most accurate methodology currently available, and there is no doubt that it is completely impartial.
Don't try to make it sound like Wimbledon is making a terrible error, unless there is a better option available.
You mention that a football with a tracking device needs to withstand being kicked. However the position of a football being kicked only matters when it is punted to the opposing team or when it is kicked for a field goal. Since the uprights make the latter situation simple to determine, the only real situation that the position of a kicked football matters is when a punt is returned near the sidelines. Luckily, a punt is not nearly as punishing on a football as a place kick, so a tracking device would no doubt be able to survive a punt.
Having exact positioning on a football in play is a huge help since refs are notoriously inaccurate, especially in the red zone when inches determine whether the football crosses the plane or falls short. But then again, griping about the refs is one of the aspects of the game.
Last year they showed a hawkeye image in Cricket that showed the ball going down the leg side. Now I know that one was false since leg stump was about five metres away from where it should be.
While the hawkeye certainly isn't perfect, I almost guarantee that its at least a few orders of magnitude more accurate than the human eye.
I don't see where the controversy is, the rules are simple, the ball is either in, or its out, theirs nothing left to human discretion, so nothing is lost by removing the human element.
Why this shouldn't be used whenever its available?
Those at the professional level of tennis such as Roger Federer (Current World #1) are completely against the Hawk-eye system. During the 2007 Wimbledon final against Nadal, Hawkeye called in a ball that appeared out to everyone, and Federer, a usually quiet guy actually told the umpire that it was "killing" him. The main problem here is that before Nadal "challanged" the call, it was presumed to be out, however Hawk-eye said differently, so the umpire was in complete agreement with the hawk-eye.
However, the actual problem is that because it is a machine, people trust it to be right 100% of time, even though on more than one occasion, that has been proven wrong, just like the previous "cyclops" system that used to be used to call if a serve had gone past the service line (white line in middle of court). That is why a lot of high ranked players don't agree with the hawk-eye system because it takes out the responsibility of the umpire to do his job, which is to make difficult line calls. The players have enough to worry about without needing to make line calls.
For those that didn't care to RTFA, the study is in the journal 'Public Understanding of Science' and (gooly who would have guessed) doesn't have anything to do with the summary written. They argue that uncertainties in measurement that normally don't impact the layman now need to be presented in an understandable way. They worry that people will wrongfully become too trusting of the systems that do have appreciable error in rare circumstances.
To inject my own opinion on the matter, I've had a little bit of experience with Vicon motion capture systems which appear to use similar technology to the Hawkeye system. The main problem with the system (when it works) isn't any problem with accuracy or precision. In fact, it's awesome. The problem is that the output is a little noisy and suffers from occasional jumps and hiccups. With proper filtering these are eliminated and the output is amazing. I can only imagine the problem is much easier when you're tracking a single ball rather than tens of tiny reflective makers such as with the Vicon system.
You gotta find first gear in your giant robot car
From article: The machine reported that the ball nicked the baseline by 1mm. However, Hawk-Eye Innovations also report that the average error of the machine is 3.6mm. If the Cardiff analysis is correct, the errors can be even larger than 3.6mm on some occasions. The International Tennis Federation, which tests the machines for use, would accept that Hawk-Eye had passed its test if it called the ball in by 1mm while the true position was out by 5mm.
Only 5mm? A human judge watching a fast-moving ball is NOT likely to do better than that.
Table-ized A.I.
I just reread the bit about complementing equations, and I'm actually the one who used that word first, so you're off the hook on that point - I shouldn't be carrying on three unrelated conversations at the same time ;)
Because that's not the issue. You'll always have uncertainty in systems. The study argues that the public perceives these systems as infallible, and therefore believe that technology can provide a final, absolute arbitration. The study is commenting on this tendency in lay people (i.e., people without specialized knowledge of the system), and warns against the corollaries that stem from such assumptions. Also, the title is bad: they are merely looking at the issue through the lens of Hawk-Eye, they're not looking at Hawk-Eye specifically. You may note that there is no analysis of the hawk eye system beyond a basic discussion of its function.
Just put high-powered lasers firing down the lines. If the ball is melted slag, it was out.
The New York Times references are several years old. The Wikipedia article you mention says the controversy has died down and the system has brought the intended benefits.
I wish they would just use an automated system in all the parks instead of relying on the umps. I also wish they would use a standard strike zone, instead of one that changes based on the batter. It'll never happen, though.
The articles don't really answer some key questions about how the system determines if the ball hit the line. I guess the details are in the study. Anybody read it out there?
The article says the system takes into account the compression of the ball and the fact that it skids on the ground. So the system tries to determine which parts of the ball actually touched the surface? Those must be some statistical calculations because I don't see how the system can actually see the ball compressing in 3d or tell which parts are actually making contact with the surface. So this is where we get the 3mm error. This brings a good point of the results during a game are within 3mm, should they be accepted.
Baseball would be FAR more difficult, if not impossible with a generic system, or at least that is my opinion. In tennis, football, etc. you have an exacting standard. Baseball fields are all different. Each one has different sizes, even the actual distance of the basepath may vary in distance though it isn't supposed to. Each player's height and stance is different meaning that there would be a great deal more difficulty if used to determine (in real time at least) the strike zone. I think the best solution that I have seen so far has been the American Football's system of review after a coach's challenge or those called by the head officials in the latter minutes of the game. Please keep in mind that my knowledge of tennis is limited to just a couple of years back in high school but my baseball experience is much greater so I may have a heavily biased view of the complexities involved with the variances of baseball.
"So long and thanks for all the fish."
It doesn't matter how good, or even how bad the system is. As long as it cannot be shown to have a particular bias to a player, or the side of the court then it is automatically more fare than any existing judge.
period.It doesn't matter if it is even out my 5 centimeters, never mind having an error rate of less than half a centimeter.
I'm confused. Why would umpires oppose a technology that can automate the refereeing of a game? It just doesn't make any sense.
Information theory is life. The rest is just the KL divergence.
For a system like Hawkeye to be useful, it doesn't need to be perfect. It just needs to consistently be more accurate and impartial than a referee can be.
Nor is it required for the system to be fully automatic and autonomic. Referees can sit in front of their monitors, observe the cameras from all angles, with any time slowdown, and ultimately come to a better decision than a single person could make while the ball buzzes past them at Warp 9.
But from the social aspect, one has to decide on what is the referee's role, and what kind of influence, if any, do we want to delegate to a computer. And that depends on the type of sport.
For non-interactive sports such as sprinting, an automatic system works very efficiently, and most people readily accept it as better than a human time tracker.
But for many GAME sports (soccer and boxing come to mind) many people consider that a referee is PART of the game rather than just an observer. As long as a referee is comparatively competent, and acts in good faith, he has the authority to judge events in the game, and while mistakes are unavoidable, they are considered part of the game as well.
I'm not sure why this position is popular in these kinds of sports. Maybe it's the whole "humans should be judged by humans and not machines" aspect. Or maybe it's because having a Review Comission in front of CCTV monitors be judging every little move just feels too 1984-rish for spectators and players alike. Or maybe its something else. But this is a rather popular feeling.
Depending on the features and benchmarks of the electronic system, it may or may not be more accurate than a human observer. In the long term, a joint human-computer analysis system would be certainly more accurate than a human referee alone, especially in team or high-speed sports. But one has to ultimately question, whether, by gaining mathematical precision, we lost some human touch of sport that makes it enjoyable to play and watch. Fun can't be generated with a mathematical formula. And sometimes sitting on the couch and thinking "OMG that referee is such a dumbass" is part of the fun as well.
I would accept the computers call over umpires any day of the week!
rubbish! then what would we all have to argue about afterwards in the Pub?
Actually Hawkeye is pretty poor for cricket.
Hawkeye cannot 'hear' a snick to give a 'caught behind'.
Hawkeye cannot (as far as I can tell) decide if a ball is caught or if the fielder let it slip through his fingers as he scoops it up the ground.
Hawkeye cannot tell if a Leg Bye or simple bye was scored.
I don't believe it can decide a 'wide' as there is no fixed length rule.
Hawkeye cannot tell if a ball was caught inside or outside the boundary.
Hawkeye cannot decide a run out.
Hakweye cannot tell if the ball hits the helmet often left behind the wicket keeper (5 runs)
Hakweye cannot even decide a no ball yet.
and so on
The only thing Hawkeye was/is used for is to decide an LBW decision which is a small percentage of 'outs' in a given game, and also to show where balls have been pitched for a given bowler.
Umpires in Cricket are going nowhere.
They have already experimented with this idea, but had problems keeping the sharks under control.
Have a look at soylentnews.org for a different view
Review? are you kidding?
Do you know how many "close" pitches there are in an average baseball game? I think they were working on lowering the average time of a game, this would shoot it way back up.
You win. I hadn't thought of that. Though, again, I didn't mention that the review system for football should be used for baseball so I have a way to deny all accusations. *grins*
(Really, I hadn't thought of that. Wow. That'd ruin it. I figured that that system had worked well for that game.) I played in college and actually wanted to consider an attempt at a career before admitting to myself how unrealistic it was and so I have a love affair with baseball so I'm at a loss of how we can automated the refereeing. I see there being so many variables that it'd be impossible to automate the refereeing without altering the game in and of itself. Gots any ideas? However, no no no.... The replay system used in football would suck for baseball though it works well for that game, I think. If anything I think there should be a "pitcher nut scraching" time limit as well as a single step into the batter's box. (Yeah, some people hate me for that one. You step into the batter's box and step out it should be a strike like a balk. With the new guy pitching with both hands we may need a few minutes resolving it but I'd say offense goes first so the hitter picks first but that's WAY too much digression here.)
"So long and thanks for all the fish."
It's funny how the slashdot community is so clear headed and informed about apparent impossibility of something as seemingly simple as putting a radio transmitter in a tennis ball, but then turn into pseudo religious nuts when it comes to uploading their souls into future AI networks. There's no consistency here.
There is a fine line between being a cultivated citizen and being someone else's crop. - A. J. Patrick Liszkie
I dunno, I guess some people just like to keep their jobs.
I'm sure you've all noticed that since the
introduction of Hawkeye, Networks have all
consistently stopped showing those wonderful
slo-mo replays, which, more often than not, would
simply show that the machine was in error.
The irony, of course, is that those replays are being
ignored just at the time when high speed camera technology
was getting good and cheap enough to be useful for umpiring.
A much better system is to have players be allowed
to ask an umpire for a video replay on demand, being able
to be wrong at most twice in a row.
If the point of the article is mainly to awaken public perception about machine referees,
then sentences like "but the fact that the machine can also make mistakes should always be clear." don't help at all.
People should have at least the awareness that as long as they aren't broken and function as designed,
machines don't make mistakes. (A mistake being the same as 'producing output not in accordance with the input and the design specification' in this case).
Machines however, CAN be inaccurate and often this inaccuracy is part of the design specification.
Equating inaccuracy with "making mistakes" is as bad in misinforming the public as it is to maintain the aura of perfection that surrounds sophisticated machinery now.
The only way to do it would be to develop the system so that is as accurate as possible. Sensors in the uniforms to measure the strike zone, sensors in the bat to determine if they check the swing, etc.
If you can't get it to the same accuracy or better than an umpire, forget it.
After doing that, you'd have to disallow reviews. That would speed up the game. The umpire NEVER changes his call when anyone argues with him, so people could storm out and have just as futile a conversation with the umpirebot 2000
All this strikes me as a more-or-less semantic argument. Yes the system has flaws, and yes it's the best we've got. Nothing to see here...
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But one has to ultimately question, whether, by gaining mathematical precision, we lost some human touch of sport that makes it enjoyable to play and watch. Fun can't be generated with a mathematical formula. And sometimes sitting on the couch and thinking "OMG that referee is such a dumbass" is part of the fun as well.
Watched the Aussie Open or Wimbledon in the last couple of years? I, and most other observers, consider that Hawkeye makes the game more enjoyable, and whilst probably isn't 100% accurate, is better than having players constantly whinging at the line judges and a constant feeling of 'unfairness' being held by a player because they think the human linejudge made a significant mistake (and maybe they did). Hawkeye won't make a SIGNIFICANT mistake.
== Jez ==
Do you miss Firefox? Try Pale Moon.
... and use a infrared camera. Problem solved.
>For non-interactive sports such as sprinting, an automatic system works very efficiently
The system (photo finish) used in sprinting isn't exactly automatic. A line scan image is taken of the finish line as the runners cross and a human looks at the image to determine in which frame the chest of a runner first appears.
I am not sure how many cameras are used in Tennis, but I am guessing they use at least 6 of them to triangulate which I believe produces an accuracy better than that a human can produce.
IIRC, Hawkeye was introduced in cricket to judge LBWs (Think of it as the ball hitting the batsman on it's way to the stumps). Now the rules say that any doubt must go in favour of the batsman, but obviously common sense prevails and umpires make a subjective decision on whether or not the ball is going on to hit the stumps. Hawkeye actually predicts the motion of the ball for about 1.5 meters after it has travelled about 20m in these decisions and makes a call (without concern for an 'error volume'). I would say that Hawkeye for most part is extremely accurate in the tracking with cameras placed >60m away with the ball typically moving at ~50 - ~100mph and moving in the air and after bouncing and usually better than the human umpires at predicting the path of the ball. The reasons it cannot quite work in cricket to make decisions is that LBW decisions involve things that hawkeye can determine (like where the ball pitches and where the ball is headed) and things like batsman's intent and whether he was attempting to play a shot that it cannot.
With them extending this technology to tennis, I cannot imagine that it would be any less accurate than a human being. Since tennis does not specify any direction of benefit of doubt, I think what the system could display is a 'Probability of being in/out' based on the error volume calculations and then decisions could be made depending on that (maybe original call stands if either of the probabilities is 0.25 or something).
Cheers!
Atheist: Buddhist in a Prius
I am not sure why people put technology to higher standards than humans. TFA (yes! I read it!) says this:
Led by Professor Harry Collins and Dr Robert Evans, the team argues that such devices could cause viewers to overestimate the ability of any technological devices to resolve disagreement among humans. It also suggests that a more detailed understanding of how the device works could play a vital role in public education the benefits of which could spread to all technological decision making in the public domain.
I am not sure Hawkeye CAUSES people to think machines are infallible, but it's rather backwards where HAwkeye is assumed to be infallible BECAUSE people expect computers and machines to be correct 100% of the time. The potential for error by a computer is alien to most people (not least because people like my idiot CS teacher in school keep telling you that computers are 100% accurate and that they never tire). For some reason, there is reluctance to accept automated systems that are not 100% perfect.
If you were to invent a self manoeuvring vehicle which reduced the no. of accidents every year to 50% of current values, that would still not be implemented (in today's society) since every single on of us 'KNOWS' we drive better than the cars. I am not saying we should trust machines implicitly - I am just saying technology should not necessarily be held to superhuman standards.
Cheers!
Atheist: Buddhist in a Prius
You should be using the metric system.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
You Pierce me with your wit! It Burns! When you finally drag out your Winchester and kill me, you'll have to bury me in a field fit for a Potter because I can't afford anything better.
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Do read the rather scientific reply from the proprietors: http://www.hawkeyeinnovations.co.uk/UserFiles/File/Microsoft%20Word%20-%20The%20Cardiff%20University%20press%20release%20of%20June.pdf
That ball was on the line!
There exists no way of exchanging information without making judgments. --Bene Gesserit Axiom
why keep track of the ball, when you can keep track of the court it's much easier. the court doesn't move, doesn't change. Place sensors on the lines, pressure sensors, etc and track that. they can make grid sensors that can show sub-mm activation. Even easier you could weave a semi conductive polymer thread into the balls, and place a parallel wire system into the lines, if the balls hits the lines,a computer would be activated then. anyway, just my two ideas.
Even easier, on clay courts they look at how the paint line is disturbed, it would be simple enough to paint the lines with an additive that reacts to the friction of the ball heating up the surface momentarily, or pressure contact, for a visual indicator as effective as clay courts. K.I.S.S. (Of course, there's rarely profit to be made in the simple effective solutions.)
What would even be the point of an automated system that "gives the benefit of the doubt" or reproduces human errors? Maybe I missed the point, but it sounds very close to pointless if you do that kind of thing. "It was in, but many people probably think it was out, so... ok it's out."
I would much prefer to see the evidence and the margins of error as they mentioned. It seems smarter to make the rules of the sport incorporate the equipment used and have set decisions about how to handle calls when they are within the range of uncertainty of the mechanism.
I'm not sure why this position is popular in these kinds of sports. Maybe it's the whole "humans should be judged by humans and not machines" aspect. Or maybe it's because having a Review Comission in front of CCTV monitors be judging every little move just feels too 1984-rish for spectators and players alike. Or maybe its something else. But this is a rather popular feeling.
Must it really be any more than just wanting to have something to argue about in the pub?
Watching the entirety of soccer and boxing matches and paying attention, the first times for both, I was completely shocked at the referee's control over the outcome of the game. They can basically arbitrarily decide the outcome.
But without these events, large groups of drunk men would have had nothing to talk about for an entire night. Each outrageous event is also good for a 15-minute debate every 3 months for the rest of your life.
Soccer provides a lot more chance for these debates than boxing. Of course Baseball provides for some. But on the average, the rest of the world has more time to spend doing nothing than Americans. So they need sports that are more arbitrary, and provide more situations for debate.
Yeah, I know, this is /. and I'm not new here so I should know better....
But TFA is about how to USE automated systems and how to EDUCATE the public about the capabilities and limitations of such systems. In particular, they mention the need to have people understand that Hawkeye is not perfect. This is not a new problem -- how many of us old folks can remember any number of times that a retail clerk will say "but the cash register/computer says the price is X," or "the computer says your bank account is..." when it's bleedingly obvious to anyone with half a brain that the database is fouled up?
The point is that people need to know how to interpret the accuracy and precision of automated systems, and how to interpret error bars as well. How many times have you seen a newscast say "Bob is leading Joe in the polls by 5% with a margin of accuracy of 6%," and then go on to claim that this makes the race a "statistical dead heat"? Which of course it does nothing of the sort.
Personally, I'm happy with any system (back to sports) which is fast, reasonably accurate, and is deemed by the Rules Of The Game to be the final arbiter. Either the head umpire or Hawkeye gets a decision in tennis in about 10 seconds. Compare this to the bullshit that goes on every time an NFL ref goes to the sidelines to look at "instant replay" video.
https://app.box.com/WitthoftResume Code: https://github.com/cellocgw
'soccer'? Football.
The main reason replays and other more advanced technologies aren't used in football is because the game does not have natural break points in which to use them.
It would destroy the flow of the game and damage it as a sport and as a spectator sport to create additional stoppages to check things.
As an example.. someone enters the penalty area with the ball; they are tackled and fall to the ground. Were they fouled? The referee says no, the defending team welly the ball upfield and score.
Imagine we had to use a replay to check whether there was a foul and a penalty. When do you check it? At the time? You can't, the ball is in play. At the next stoppage? A goal was just scored at the other end, are you going to risk writing that off, even though it may be 4-5 minutes after the incident you're checking? It's just unworkable.
For a sport like tennis or cricket where the action occurs in discrete events there are natural pauses in which such things can be checked. In a sport such as football the continuous flow of the game would be broken. That's why technology hasn't been used to aid the referee, not because people prefer controversy and the risk of human error.
This system has turned me off of tennis anymore. It is not acceptable to totally rely on this technology when they already have a system available to more accurately determine what happened. It's called HDTV. They have enough HD cameras around the court to show what happened from more than one angle.
A few years ago I watched some of the French Open and the system was not officially being used, but it was used in the booth and the announcers commented on close line calls with it. I saw five line calls that were close enough that they used the system to 'check' the officials and 3 of the 5 Hawkeye results were wrong! How do we know? Easy! Playing on clay leaves visible marks on the surface that are proof of the contact area of the ball. Since I rarely watch anymore, do they use it at the French now?
Still, I do not believe that the computer system can accurately calculate the deformation of the ball as it impacts the surface and the distance the ball slides before it leaves the surface. Finally, if the system is now used as the ultimate authority there is no reason to have any line judges. The umpire remains to run the replay controls, but all judges should be removed so that there is no confusion introduced by humans. Players makes their own calls and if the opponent questions it, they show the replay. Gameplay would only be slowed momentarily because they should remove all the animation and just show the final frame and say 'in' or 'out'.
The real benefit of Hawkeye as well as the three "challenges" granted to each player is that it has had a very positive impact on player behaviour.
Gone are the days of endless bitching at the line judges, swearing at the umpire, and throwing tantrums instead of playing the next point.
If the price to pay for that is a slight risk of inaccuracy, so be it!
"To strive, to seek, to find, and not to yield." -- Tennyson
The same passive tech built into Door Cards and anti-theft stickers is woven into the material of the ball, with the weight and consistency difference taken care of by the manufacturer to keep the balls feeling as "true" as possible.
Maybe even give each tournament sanctioned ball a unique serial number, should make for a much hotter collector's market :)
Then you could put RFID transmitter/receivers in/under the out of bounds paint itself, and perhaps further away, to get as many readings as possible to track the ball.
Just an idea.
What, me worry?
Actually, there's some sense to your comment. Why not just run low power lasers along the lines (think laser pointer power levels, but with a tighter focussed beam)
If there's a dispute, look at the close up of the ball. If there's a laser dot, it was on the line.
Who verifies that the replay by Hawkeye is really the shot just played. What's to stop the hawkeye operator just selecting the secret "give me the most similar replay(to the actual replay) that was out". Or in depending on which player is your paying customer. With the amount of computing power they have got, that would be easy. A whole match can turn on a couple of points. 5 all in the 5th set tie breaker. Wrong call(ie don't actually show what happened). All over
That applies to the human eye as well.