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."

Comments

Why not use...

[Kagura]

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.

Re:Why not use...

[Bun]

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.

It's been tried in soccer. The latest attempts were prior to the last couple of World Cups IIRC, but the systems were plagued with problems, not the least of which was the survival of the transmitter.

http://www.gizmag.com/go/2790/

Re:Why not use...

[icegreentea]

Assuming you could build a radio transmitter tough enough to handle it...

With tennis balls, I imagine there would be problems with balance and the response of the ball. Especially with such a small ball, mounting a rugidtized radio transmitter (a ball probably has to go through 20gs or something) would probably mess with the balance and how the ball deforms. Not to mention, unless you can mount the system directly in the center of the ball, then you still have a margin of error the diameter of the ball. I imagine that would be fairly significant amount of error in tennis (perhaps on the same level as this Hawkeye system?) when calling the lines.

Re:Why not use...

[InadequateCamel]

Further to that, if the transmitter can't survive in a soccer ball (where a well-struck shot probably moves around 120-130 kph) then there's no way it will handle travelling over 200 kph after a serve, followed by a (at least) 100 kph forehand return (a net >-300 kph in a fraction of a second!).

Also, a radio transmitter cannot account for the distortion of a ball upon impact, which will depend on velocity, angle of rotation, angle of impact, surface being played on, etc etc etc...

Re:Why not use...

[jfim]

Triangulation of radio signals is not accurate enough to give sub-centimeter accuracy and the added mass to the tennis ball would probably cause the players to have some objection to adding a radio transmitter into the ball.

The claim that the Hawkeye system gives an average of about four millimetres of error seems somewhat reasonable, given that we're getting accuracy greater better than two centimetres on detecting objects with a single camera with optics as large as the last segment of a typical pinky. (FWIW, here's a short demo of what we're working on for our autonomous underwater vehicle)

However, the suggestion to display the error range for a particular shot and leaving the final decision to a human from TFA is quite reasonable and is how it should be. Blindingly trusting technology or discarding it altogether is unreasonable.

Re:Why not use...

[Sethumme]

I still don't understand why there isn't more research on developing a surface for the out-of-bounds area that temporarily registers the exact impression of any impact on it.
I envision something that looks like a big LCD touch screen (but more durable). Every time something made contact with the active surface, a record of the ball's "footprint" could be recorded (and even temporarily displayed wherever it touched the surface). That would allow for highly precise measurement of the ball's landing position, and it wouldn't need to incorporate any new materials into the ball itself. The active surface would only need to be in the out of bounds area, and even then, it would only need to be half a foot wide in order to cover the important zone where the ball's landing position is questionable.

Re:Why not use...

[Drathos]

Fox tried to do that with hockey back in the 90s in order to make the puck easier to see on TV (personally, I've never had a problem seeing the puck). The Glow Puck was horrible. When there was a jam up in the corner, it would literally be bouncing all over the screen. It also changed the way the puck performed on the ice. Because of the electronics and battery inside, they couldn't freeze the puck like they normally do, causing it to bounce a lot more and not slide on the ice as easily.

In a hollow sphere like a tennis ball, how would you keep the dynamics of the ball the same as they are when you add a transmitter to it? If you adhere it to the side, the ball will be off balance. If you create some internal structure/support to keep it centered, you change the deformation during a bounce/hit.

Re:Why not use...

[Don_dumb]

At Wimbledon you could have chalk for the lines and if you were unsure if the ball hit the line one of the competitors could point out that

"the chalk flew up"

Re:Why not use...

[jez9999]

Could someone explain to me how this would be any more precise than high-quality optical analysis? Usually, in the slo-mo replay recorded by even the *average* quality cameras for TV audiences, you can almost always tell whether a ball was in or out. Make that higher quality cameras with a higher frame rate, and optical analysis seems like a very good way to do it, to me. It is, after all, what human umpires do.

Re:Why not use...

[rant64]

Also, a radio transmitter cannot account for the distortion of a ball upon impact

I seriously doubt that an umpire can.

Hawkeye's also being used in snooker now, and it actually looks very accurate. The refs always re-spot the ball at least 2 inches away from the spot where it was, and I don't see why they're not using this more often.

Honestly, even if the Hawkeye system is off by a few millimeters, if I were a pro tennis player then I'd rather have a call which is at most 3mm off than being called by an umpire who maybe wasn't paying close attention and calls whatever he thinks is right.

Re:Why not use...

[Anonymous Coward]

...leaving the final decision to a human from TFA is quite reasonable and is how it should be.

No it isn't, it's ridiculous. On what basis is an umpire supposed to over-rule a machine with 4mm accuracy? True, the machine may be "wrong" from time to time but by trusting a machine you create a deterministic rule set which is completely neutral. It is precisely the fact of removing a human from the equation that makes Hawkeye so useful and so MacEnroe proof.

Re:Why not use...

[Keychain]

Yeah i hear they invented something like this : every time the ball touches the grounds it leaves a visible mark. i think they call it Complex Layer Against Yelling, but i doubt Wimbledon and its tradition are ready to take the plunge

Re:Why not use...

[nine-times]

Blindingly trusting technology or discarding it altogether is unreasonable.

I disagree. Since this is a game, it seems to me the most important thing is that the rules are applied consistently and impartially. Accuracy may be the goal of making the rules, but once the rules are set, I'm much more concerned about the consistency and impartiality.

They played tennis for quite a long time without the technology, and so it's evident that discarding it altogether wouldn't be so bad. Accuracy isn't really the issue. You could decide all disputes with the roll of a 12-sided die, and it would still be fine, in the sense that it would become part of the game and players could adjust their strategies accordingly. As long as it was consistent, it would be fair.

So the only question in my mind is, is the Hawkeye inaccurate in a way that would cause players to use strategies that would be bad for the game. For example, if it were truly random, then players might start appealing every call. If they have nothing to lose and a random chance at success, then why not?

But the use of the Hawkeye system doesn't seem to have any effect like that on the game, so I don't see what the problem is with trusting it blindly. Even if it makes occasional bad calls, they don't seem to be any worse than the call a ref would make. If anything, in those instances, it might even be better for a machine to make an arbitrary bad call, because at least you know the machine won't favor a particular player.

Re:Why not use...

[CastrTroy]

They've been using human referees for a long time, but they really haven't had any other option up until this point. You could say the same thing about the introduction of the car. Everybody's been using horse and buggies for getting around for a long time. Since they've gone so long without the technology, it's evident that discarding it wouldn't be so bad. Even if the error is as large as 1 cm, I would say that's pretty good. How good is the accuracy of human vision at a distance of 40 feet with an object moving at 200 km/h?

Re:Why not use...

[bh_doc]

For example, if it were truly random, then players might start appealing every call. If they have nothing to lose and a random chance at success, then why not?

Wimbeldon, IIRC, has a limit of 3 appeals. Just as an example.

It doesn't have to be perfect

[davidwr]

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.

Re:It doesn't have to be perfect

[Fred_A]

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.

Another method would be to use Radar instead of Hawkeye. Probably faster and more efficient as well.
(obscure reference).

Re:It doesn't have to be perfect

[frdmfghtr]

Another method would be to use Radar instead of Hawkeye. Probably faster and more efficient as well.
(obscure reference).

In the event of a tie between the two systems, perhaps a Honeycut system to break the tie.

Re:It doesn't have to be perfect

[Oktober Sunset]

Obscure to people with a life, but as this is slashdot, there aren't many of those around.

The only solution

[Anonymous Coward]

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.

Why not, it works for shopping carts

[davidwr]

If you leave the store parking lot, one of the wheels locks.

Re:Why not, it works for shopping carts

[Anonymous Coward]

So if one of the players tries to steal a tennis ball, they won't get very far?

Re:Why not, it works for shopping carts

[sconeu]

Unfortunately, for my local supermarket, "leaving the store parking lot" is defined as entering the store.

Re:Why not, it works for shopping carts

[b4dc0d3r]

That's compatibility for legacy (analog) shopping carts with the one wheel stuck sideways.

Anonymous Coward

[Anonymous Coward]

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.

Re:Anonymous Coward

[the_other_chewey]

The accuracy has absolutely nothing to do with the overdetermination of the system.
If it had, it would be simple to reduce the number of cameras to three, and boom - perfect position.
That's obviously not how it is.

And of course does the number of cameras increase the precision of the computed position - the principle
is exactly the same as for GPS, where more satellites are better as well.

Using a certain fitting method (least squares, least absolutes etc.) has nothing whatsoever to do
with something like "complementing the equations", that's just necessary because no measurement is perfect -
You are arguing that multiple measurements do not increase the accuracy of a computed average because there
are multiple averaging algorithms to choose from.

Bullshit.

Re:Anonymous Coward

[DrJimbo]

Since we're only dealing with three dimensions, why would any number of satellites > 3 be more precise for GPS?

If the errors are random and follow a normal distribution (two big ifs, I admit) then even in one dimension, the error is reduced by a factor of 1/sqrt(N) where N is the number of measurements.

The same general idea applies to higher dimensions. If you can avoid systematic errors then the more measurements you take, the more accurate your final result will be. If you are interested in the gory details of the higher dimensional case, you should take a look at singular value decomposition.

Re:Anonymous Coward

[the_other_chewey]

Since we're only dealing with three dimensions, why would any number of satellites > 3 be more precise for GPS?

Because we are dealing with reality as well - where no measurement is perfect.
Geometrically, three sats indeed are enough, but in reality:
More measurements -> smaller error bars -> better position.
The alternative to more sats would be not to move and to take more measurements over time.
But that would render GPS useless for most applications ;-)

Additional trouble with the "stay and wait" method: Those nasty satellites move over time,
introducing different errors that can not be eliminated as easily by simple averaging.

That's also why ultra precise GPS surveying records the satellite data and waits for the week it takes
to make the actual orbital data (as measured, and not just as predicted) available before computing
the position, thereby elimiating (well, at least reducing) another source of error.

In statistics, the only thing beating multiple measurements is even more measurements.

Re:Anonymous Coward

[Rakishi]

A system such as Hawkeye CANNOT BE MORE ACCURATE than humans.

Of course it can be, humans are not 100% accurate and even human eyes aren't 100% accurate.

From the link in the article, the Hawkeye system uses 5 cameras to compute the 3D position of the ball. That's an overdetermined system of equations, which cannot have a unique solution due to observation errors in the camera views.

That it's overdetermined doesn't matter since in the end the error of those combined non-unique solutions is still less than that of a non-overdetermined system of the same cameras.

So Hawkeye has to complement the equations with an ARBITRARY rule, eg least squares, and this arbitrariness makes the Hawkeye estimate neither more accurate nor less accurate than humans, just different. FYI, there are plenty of other arbitrary rules that work, eg least absolute errors, maximum entropy, etc.

That it uses an arbitrary rule says NOTHING about it being capable of more accuracy than a human. Accuracy is easy to determine (via experimentation if you wish) and claiming that we somehow magically can't measure it is idiotic. For example a checkers program plays the game differently than a human but one can still claim the program is better than a human (since no human can beat the best checkers program from what I remember). It may be possible that neither humans nor this system are better in every case but that still doesn't mean one can't inherently be better (ie: if the cameras are accurate enough). In fact even if one doesn't dominate the other one can still uses some measure to determine which is more accurate (on average, etc.).

Re:Anonymous Coward

[SnowZero]

A system such as Hawkeye CANNOT BE MORE ACCURATE than humans. From the link in the article, the Hawkeye system uses 5 cameras to compute the 3D position of the ball. That's an overdetermined system of equations, which cannot have a unique solution due to observation errors in the camera views.

Luckily there's a 100+ year old discipline called statistics, and 60+ years of literature on tracking to help you out in these cases.

So Hawkeye has to complement the equations with an ARBITRARY rule, eg least squares and this arbitrariness makes the Hawkeye estimate neither more accurate nor less accurate than humans, just different. FYI, there are plenty of other arbitrary rules that work, eg least absolute errors, maximum entropy, etc.

While I can't speak for the designers of the Hawkeye, in tracking there are very good reasons to choose one form of error minimization versus another. It only seems arbitrary because you are not informed on the subject, but there's plenty of free papers out there to read and discover.

To explain current methods, please start out with this paper, in particular Figure 2, you'll see that the sort of errors you get from a camera are indeed well fit by a Gaussian. While a camera's perspective transformation is not purely linear (and various forms of distortion make it also non-linear), a good camera with a decent lens estimating the ball location within a limited area is well approximated by a linear model (and you can characterize just how much the error is). Now, a bunch of cameras with a Gaussian error distribution in the image plane with a linear projection out into the world is still a Gaussian (with a transformed covariance matrix). You can then multiply the independent measurements from multiple cameras to get a better estimate. Add a time series to that and apply this recursively and you get a Kalman filter, something invented for aerial tracking and still in widespread use today. If something is good enough for missiles to intercept other missiles, it ought to be good enough for a tennis match.

If the linear approximation not good enough for you, you can use a Rao-Blackwellized Kalman filter. If that's still not good enough because you want to use another error distribution or non-linearizable dynamics, set up a particle filter with a whole lot of particles and enough CPU to simulate it. The point is that what you call arbitrary is a well studied field which is many decades old. You'd be best served by learning about it first before you cast away all that work. I'm not a "tracking" person, just a user of there work. When a field of science has done its job well enough that it has become common engineering, and you can go look up whatever you need in books, with all the derivations, caveats and tradeoffs laid out there for you to see, I would say that that field has done a pretty good job.

The whole media story around this paper is ridiculous. It's a paper from a social sciences department about how the public does not understand the fallibility of these machines due to noise. That's all this paper is about: Hawkeye has error. I hate to break it to the uninformed, but all measurement systems have error. From Galileo to Gravity Probe B, your results can only be as accurate as your measurements, calculations, and statistical models will allow. You can decrease error with various methods, but you can never completely eliminate it. People should not be able to get out of high school without understanding accuracy on measurements, and some rudimentary statistics, but unfortunately our education system hasn't been able to reach that goal. As a result, the public doesn't understand error, and might come to believ

Re:Anonymous Coward

[eh2o]

Combining observations isn't arbitrary, its based on prior knowledge of the underlying statistics and measurement methods. If the multiple measurements are identical with normally distributed error, for example, the mean can be used. If the measurement is subject to random catastrophic failure (e.g. bit flipping), then the median is a good choice. In the Bayesian method you form a composite probability distribution by combining conditional or joint probabilities. In fact, if you do it wrong, you can make the final answer *worse* than any of the original measurements (this is called catastrophic fusion). The method is NOT arbitrary--making that assumption will get you into big trouble fast.

By the way a system like this has potentially many, many more observations than just five--since it also uses position and velocity estimates from previous frames to compute the most likely next position of the ball. With five high-speed cameras combining data into a Kalman filter you are looking at hundreds if not thousands of measurements of the ball trajectory, which will give you enough data to estimate subtle qualities like the spin of the ball and so on (by extension the number of variables is by no means limited to three, since one can estimate any number of higher order features--e.g., velocity, acceleration, angular velocity, wobble, etc).

It isn't hard to engineer machines that surpass the accuracy of a human in a variety of tasks, and the question of "which one is right" is not merely subjective but described up by a body of math known as signal detection theory. This math by the way came out of the subfield of psychology dedicated to measurement of the thresholds of discrimination by human judgement with respect to physical phenomena--psychophysics. The resolving power of a measurement system can be quantified by its discriminability index, and decision-making processes based on that information are described by positions along the corresponding ROC (receiver operating characteristic) curve.

Re:Anonymous Coward

[Rakishi]

You're missing the point. Accuracy makes no sense unless you include the error criterion. Any estimation algorithm has an arbitrary error criterion, as do humans. Neither is more accurate than the other, they're just different estimation procedures.

No, talking about the size of the error makes no sense if you haven't specified a regularization criterion. Now choosing the criterion is essentially equivalent to choosing what the theoretical answer should be, so it's circular reasoning to claim that the resulting error would be smaller.

That's a silly argument because it basically says "nothing is better than a human because a human is no optimized for the problem" or "we can never determine what is better because we need to first determine what better is and there is more than one possibility." You can I'm assuming create a system that is in fact more accurate across all error criteria but that's a separate point. There already is an error criteria in place since human judges must somehow be chosen and evaluated. The computer system in fact uses a different error criteria as a stepping stone because the true measure is not as easy to write in an algorithm.

No it's not. If it were, there would be no issue. The issue is that these systems converge to some estimate, but the estimate need not be meaningful.

This system is designed in the end to determine if a ball is on one side of a white line or the other. THAT is the error criteria and everything else is irrelevant or just a step to that end goal or an easier to measure version of that end goal. Interestingly enough the comparison isn't versus humans but rather versus humans using the existing computer system.

For example, do you want to minimize the Euclidean distance of the estimated position against the true position, or do you want to minimize the error in a single coordinate only, or maybe you want to minimize the roughness of the trajectory of the ball over some time interval, or ....

This is irrelevant to using over determination since the problem probably also exists with even 3 cameras. I'd guess that their placement or design parameters can easily lead to different error measures being optimized.

Re:Anonymous Coward

[Moridineas]

I'm willing to concede that you are talking theory at some level I don't fully grok. What I think you're completely missing in this discussion stems from your original statement that"system such as Hawkeye CANNOT BE MORE ACCURATE than humans", which does not seem to be possibly true by any standard definition of these words that I am familiar with.

You can talk about "error criterions" and odd offtopic tangents about targeting algorithms etc, but the bottom line is, your original statement is completely wrong.

You say "So Hawkeye has to complement the equations with an ARBITRARY rule, eg least squares, and this arbitrariness makes the Hawkeye estimate neither more accurate nor less accurate than humans".

That's both wrong and illogical. Yes, Hawkeye is estimating a solution, and using a "arbitrary" (again, this is utterly bizarre and incorrect word choice--the makers of Hawkeye have presumably done a great deal of testing to pick an algorithm, which is NOT arbitrary) method to estimate. However, if Hawkeye ESTIMATES the correct answer more often than a human judge then, Hawkeye is more accurate than a human judge. The methods it uses are really completely irrelevant to the final answer.

So in short, it seems that this is a discussion in your usages of "accurate," "error," "arbitrary," etc are different than the rest of the people in the thread.. Please let me know if I'm misinterpreting something though!

Re:Anonymous Coward

[martin-boundary]

Luckily there's a 100+ year old discipline called statistics,

Yes, and this discipline depends on something called decision theory, which in turn depends on an arbitrary choice of loss functions.

While I can't speak for the designers of the Hawkeye, in tracking there are very good reasons to choose one form of error minimization versus another.

None of this matters one bit if these reasons are not compatible with the sporting rules in the problem at hand. To be pedantic, if the rules say that an umpire has the final word (for example), then a tracking system which doesn't optimize for the same criteria that the umpire uses himself is irrelevant. To be even more pedantic, if one claims that the tracking solution is superior to an umpire's criteria if those criteria differ, one is merely trying to change the rules of the game.

Thanks for the links, but I am actually familiar with (and have used) Kalman filtering in the past. The issue I raised is not an engineering one. It occurs before engineering begins, namely in the problem specification. More precisely, I responded to a post claiming that the Hawkeye system was obviously more accurate than human referees, which I consider far from obvious and said so. Perhaps I could have talked about loss functions instead of overdetermined systems, but the gist of my point remains.

So, sure Federer can challenge Hawkeye's call, but the most you can say is what the probability of the ball being in or out is, or use the location of maximum likelihood. Maybe that should be reported on TV; Though it would confuse many watchers, maybe we can help them learn.

My understanding is that the umpire is the final arbiter. People are free to come up with a model and a methodology to compute their own best version of the head judge's decision, but unless the rules specify the methodology completely, it's merely an academic exercise with no intrinsic validity for the game.

But certainly, to talk about a system being more accurate merely because it uses engineering methodologies when the problem is not fully specified to begin with is ridiculous, and verges on technology worship.

Re:Anonymous Coward

[pyrrhonist]

Short answer: GPS units just make an estimate of your position, not calculate it exactly. More satellites make for a better estimate.

Long answer: The ranges calculated in GPS are estimates, because the clocks in the receiver aren't very precise. A small offset in the timing can cause a large error in the calculated distance (if the clock is off by 1/1000th of a second, you're actually 200 miles away from where you think you are). This is why GPS usually uses 4 satellites. If the receivers all had atomic clocks on them, every set of measurements from any three satellites would end up at the same exact point, because the clocks are so precise. The quartz clocks in GPS receivers drift out of sync with the clocks on the satellites, and this drift is enough to cause pretty large inaccuracies. In other words, if you measure the ranges from three satellites, and then subsequently measure the range from a fourth, the fourth satellite's measurement will not align with the other three. When this happens, the GPS unit makes adjustments to the 4 measurements until they all align in a single point. This effectively eliminates the clock issue. To get an even more accurate measurement, the GPS receiver will try to acquire as many satellites as possible and take measurements in groups of 4. This helps eliminate other errors caused by interference, atmospheric anomalies, highly reflective goats, etc.

Re:Anonymous Coward

[Rakishi]

Just because an umpire is the final word doesn't mean that a system can't do better than him, That is because the umpire is in fact he trying to measure something with a right/wrong answer. Specifically the umpire is the person who decides if event X happened or not which means that the goal is to see if X happened or not (not to see if the umpire thought X happened or not). The umpire isn't an inherent part of the rules but simply a judge to determine if something specified in a certain rule happened or not. As a result it's a perfectly valid problem to predict this event X in a method that is better (ie: lower misclassification) than the umpire. Finding the winner in a horse raise is one example of where technology is more accurate despite the rules likely having a person originally be the final judge.

One problem is that sometimes one can't measure the true answer in some way so there is no way to truly measure accuracy for a problem. That is a valid problem however I have no clue if that or something else is the actual problem you're so concerned about (your posts are as clear as black mud). In this case there probably are more accurate systems of measuring the truth although these take excessive money, time or preparation. One could for example cover the ground around the line with wet paint (or some such) and then check for breakages, or simply cover the ground with pressure sensors. The article implies they can measure the accuracy of the system compared to the true impact point which means that one can devise experiments in which one can measure the truth of where the ball lands.

Re:Anonymous Coward

[martin-boundary]

Fascinating. I regularly make measurements in the micrometer scale using a microscope, and easily increase the precision of my results by repeating them.

Look, statistics is much more complicated than averaging. Do you know where the averaging rule that you use comes from? It's the maximum likelihood estimator: It's a function of the observations which is obtained under certain assumptions on the physical process (which in your case would typically be a Gaussian distribution of errors, all independent).

So I should just trust my gut feeling, statistics be damned? Thanks, that'll really speed up my work.

It makes no sense to claim that accuracy is improved by averaging without subscribing to those or similar assumptions. In fact, there are other rules, for example you might add some extra dummy values to your measurements if you have a Bayesian prior assumption, etc. The point is what works in your case need not work in other, superficially similar, problems, especially if the risk function is different.

When one solves an overdetermined system, one implicitly includes some assumptions. The answers one gets are only as good as the assumptions one puts in, garbage in garbage out etc. There simply is no universal solution to an overdetermined system.

Re:Anonymous Coward

[TapeCutter]

"system such as Hawkeye CANNOT BE MORE ACCURATE than humans.......You're missing the point."

As the other poster implied, your first assertion is what the "point" is. Speaking of points, your last paragraph doesn't seem to have one, it basically says different problems have different equations and answers.

I would also suggest that an emprically derived 4mm error is demonstratably more accurate than any human and no amount of irrelevant math will change that. If what you and TFA are trying to say is, "it's foolish to belive technology is foolpoof", then a primative "duhhhhh" response is all I have.

Trivia: The aggrived player must call for the hawk-eye decision if he disputes the umpire, each player is only allowed 3 disputes per somethingorother (lady friend is the tennis fan).

Consistency, is more important than accuracy!

[Anonymous Coward]

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!

Re:Consistency, is more important than accuracy!

[Telvin_3d]

That is only true if you assume the two players are making the same level of mistakes. If both players are regularly hitting the same shots witht he same amount of error, yes everything will even out. But let's say player A can consistently serve and hit the ball to within 2 cm of the out line, but player B often misjudges and goes 1 cm over. In this case, having player A's shots consistently called 'out' or player B's shots consistently called 'in' would be consistent, but it would also make a major change in the outcome of the match. And not the type of change that gets statistically evened out over games played.

Ummm....

[Khyber]

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.

Re:Other applications?

[Anonymous Coward]

We will be able to determine once and for all whether or not they just grabbed my ass.

You're a guy reading slashdot by yourself on a saturday night. It doesn't take any special technology to know the answer to that question.

Summary Miseleading? No Wai!

[Zackbass]

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.

Read The Friendly Article

[MaliciousSmurf]

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.

Re:Call the ball Maverick

[DannyO152]

I thought it was about University of Iowa football for a while.

Re:Call the ball Maverick

[Drathos]

Army brat, myself, but my first thought on reading the headline was along similar lines.

I couldn't for the life of me think of a reason why a Hawkeye would need a system to call the ball when every other pilot in the Navy has to do it with the ol' Mk. 1 Eyeball.

Re:major league base ball umpires union does not l

[DriedClexler]

I'm confused. Why would umpires oppose a technology that can automate the refereeing of a game? It just doesn't make any sense.

Refereeing is by many considered PART of the game.

[SamP2]

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.

Re:Why not use... LASERS!

[janrinok]

They have already experimented with this idea, but had problems keeping the sharks under control.

Re:Other applications?

[InfoHighwayRoadkill]

Yes, some people also want to use Hawkeye for some decisions in cricket, the sport that first used it. However the margin of error is far greater (approximately +- 2 inches) in cricket as the cameras have to be a lot further away due to the size of the pitch.

Also Hawkeye finds it hard to pick up swinging, seaming and spinning balls. Basically anything that deviates off its theoretical trajectory either in the air or off the playing surface. Both of which are vital in the LBW decisions where the TV companies and doubtless the Hawkeye people would want to see it used.

Obviously cricket is a far more useful game than tennis so does this answer your question?

Re:Hawkeye is rather redundant in cricket actually

[InfoHighwayRoadkill]

Hawkeye cannot 'hear' a snick to give a 'caught behind'.

the tv companies have a "snickometer" which puts up an analysis of the sounds picked up by a microphone in the stumps. Its only used for commentary. The umpire makes the decision himself

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.

A good tv replay can show this but as cricket is a gentleman's game it is up to the fielder making the catch to say if he thinks he made a clean catch. There have been instances in test cricket where fielders have called back batsmen after the umpire initially gave them out.

Hawkeye cannot tell if a Leg Bye or simple bye was scored.

No but the umpire can, hawkeye finds it very hard to spot a ball that deviates from its theoretical trajectory at the best of times

I don't believe it can decide a 'wide' as there is no fixed length rule.

you answered your own question there

Hawkeye cannot tell if a ball was caught inside or outside the boundary.

Thats because its looking at where the ball is being bowled in the middle of the playing area, it doesn't cover the whole of the field

Hawkeye cannot decide a run out.

That is because it is used to approximate the trajectory of the ball as its being bowled. Not when its being throw to the stumps and the relative position of the batsmans feet and bat. TV slo mo replays decide run outs (if the umpire is unsure) and are ideal for the purpose

Hakweye cannot tell if the ball hits the helmet often left behind the wicket keeper (5 runs)

the normally loud noise the ball makes when it hits the helmet and the ball shooting off in a different direction often suffices.

Hakweye cannot even decide a no ball yet.

As previously stated hawkeye doesnt watch peoples feet it watches the ball

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.

Its only used for this purpose for the tv commentators to have something to talk about. The margin of error and the problems with picking up balls that swing in the air or move off line from the pitch make it impossible to give an accurate ruling on an LBW.

Umpires in Cricket are going nowhere.

Its because 90% of decisions made in cricket are made by the umpires without needing back up that makes cricket a fascinating sport.

Re:Other applications?

[stranger_to_himself]

Yes, some people also want to use Hawkeye for some decisions in cricket, the sport that first used it. However the margin of error is far greater (approximately +- 2 inches) in cricket as the cameras have to be a lot further away due to the size of the pitch.

The other key difference in cricket is that Hawkeye is used to predict where the ball would have gone had it not hit a pad, whereas in tennis it only needs to say where the ball actually was.

Re:Other applications?

[Don_dumb]

The reason it isn't officially used in cricket is because it would be used to predict the path of the ball had someone's legs not interrupted it. Whereas in tennis it is simply used to account for where the ball actually went.
Obviously just tracking a ball is a more definite science than the prediction of something that didn't happen (but could have). Especially as anyone who knows about cricket will tell you is that the path of the cricket ball is 'mysterious'.
I once heard a cricket commentator interviewing the inventor of Hawk-eye (a Mr Hawkins) and asked him how accurate the system was - he said something along the lines of "in testing it has been incredibly accurate" which I found quite weak as I was expecting tolerances of so many mm deviation per second.

In cricket it is only used as a commentary tool generally proving that the umpires get it 'right' most of the time anyway.

Re:Refereeing is by many considered PART of the ga

[jez9999]

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.

Re:Is it even used in football?

[aussie_a]

This is an American website. If you want to be understood by the majority of visitors, you need to use the American terminology.

O RLY?

[davidwr]

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.

You cannot be serious!

[csoto]

That ball was on the line!