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nousername
12-09-2011, 08:40 PM
Does it bother anyone else that the Hawk-eye system uses 12 HIGH-SPEED CAMERAs, yet challenges are based only on the digitized 3D ball-trajectory estimation?

Why not use the figiggin' high-speed video??? at TWELVE angles!!!

Hawk-eye has brilliantly conned the ATP and Grand Slam events into thinking their system is needed for challenges.

Is it not obvious to everyone that an umpire with access to 12 high-speed camera angles could do a MUCH better job than a computer generated estimate?

Shouldn't the high-speed video with a human at the wheel be used instead?

Especially in "unique" situations like this:

http://www.youtube.com/watch?v=IhUmGiT5GqY&feature=related

The ball clearly hit Petzchner's leg, and the point should have gone to the Poles. Playing back the 12 high-speed video feeds surely could have cleared this up.

The digital 3D ball-trajectories are good for commentary and teaching. But the video feeds that generate those trajectories should be the source used for resolving challenges, NOT the digital 3D trajectory.

this has been my pet-peeve with the pro game ever since the advent of hawk-eye ...

Sentinel
12-09-2011, 08:55 PM
I believe they've conned cricket as well.
Does Hawkeye use the wind at each and every point in its estimation ? Because I know that FedEye does. That's why Fedeye often conflicts with Hawkeye.

Xizel
12-09-2011, 08:56 PM
I remember when Tsonga saved a ball before the second bounce and the umpire thought it was two bounces already. Only the commentators' replay saw it. Although Federer ultimate won the point, the referees could use replay feedback.

Talker
12-09-2011, 09:01 PM
The ball did directly hit his leg, he was asked but he denied it. :shock:

It would take too much time and the crowd wouldn't be involved so I doubt it'll be used.

MajinX
12-09-2011, 09:02 PM
Im dont think the video you posted was a good example... coz he wasnt challenging whether the ball was out or not, he was trying to tell the umpire the ball hit his foot which the umpire did not see happen.

And from my understanding the 12 highspeed cameras are what is used to generate the 3d "estimation" visual we see when players challenge. I could be wrong about that tho.

nousername
12-09-2011, 09:06 PM
also, in those close calls where Hawk eye calls it out or in by a matter of millimeters. in those situations, it would be much better for everyone fans, players, umpires, etc. to see the 12 video fees in high-speed, and then let the ump make a judgment call. everyone would be happy with that. tennis is kind of based on the honor system, ALL calls should ultimately be based on a human's judgment rather than some overly technical digital system.

the system as used is a joke.

nousername
12-09-2011, 09:11 PM
Im dont think the video you posted was a good example... coz he wasnt challenging whether the ball was out or not, he was trying to tell the umpire the ball hit his foot which the umpire did not see happen.

And from my understanding the 12 highspeed cameras are what is used to generate the 3d "estimation" visual we see when players challenge. I could be wrong about that tho.
i'm not talking about the "challenge" made in the video, that was just a concession by the ump. he told matkowski the only challengable call in the point was the "winner" by Petzchner. so they challenged it out of desperation. i'm not talking about that challenge.

my point was that the 12 high-speed videos should be available for ANY kind of challenge. Matkowski should have been able to challenge that it hit Petzchner's leg. the 3D hawk-eye system can only make COURT calls, where as a human watching a video playback certainly could see it went off his leg.

yes, you are right. the 12 video feeds are just to track the ball and generate a 3D trajectory. then the trajectory, and trajectory alone, is used to make the hawk-eye challenge calls.

OddJack
12-09-2011, 09:12 PM
Hawk eye is pretty accurate, maybe not 100% but to millimeters.

Video cameras will not show the ball mark on the court, simply because the ball itself is always wider than the mark it leaves on the court, which is the point of impact, which is what counts.

Plus, They want to leave umpires and any other humans out of it for arguments sake.

The cameras and the computer are pretty accurate. There is simply not enough time, and sense, for umpires to sit down and watch 12 different angels and then decide if the ball was in or out and then leave the door open for arguments, was he right? Or wrong? As someone else pointed out Layhani, one of the bests, got the number of bouncing wrong, and you want him to have millimeter precision.

nousername
12-09-2011, 09:15 PM
The ball did directly hit his leg, he was asked but he denied it. :shock:

It would take too much time and the crowd wouldn't be involved so I doubt it'll be used.
it would be just as fast as hawk-eye is now. you can even show the nice fancy 3D video for the audience and commentators, but let there be one judge in a booth that watches the video feeds. let him instantly plays back points to make the "official" call when a player challenges.

woodrow1029
12-09-2011, 09:23 PM
If it were actual video, there would still be the human element of subjectiveness as to actually at what exact point contact was made with the ball and the ground.

nousername
12-09-2011, 09:24 PM
Hawk eye is pretty accurate, maybe not 100% but to millimeters.

Video cameras will not show the ball mark on the court, simply because the ball itself is always wider than the mark it leaves on the court, which is the point of impact, which is what counts.

Plus, They want to leave umpires and any other humans out of it for arguments sake.

The cameras and the computer are pretty accurate. There is simply not enough time, and sense, for umpires to sit down and watch 12 different angels and then decide if the ball was in or out and then leave the door open for arguments, was he right? Or wrong? As someone else pointed out Layhani, one of the bests, got the number of bouncing wrong, and you want him to have millimeter precision.
it IS accurate. that's one of my other issues with it. it is too accurate for the game, it defeats the essence of the game.

tennis is generally an "gentleman's" game, it's always been based on honor. at all levels (except the pros) you make your own calls. the challenges would sit better with everyone, esp players and fans, if the actual video was used. in general the rule of tennis is "if you can't tell it's out, then it's in". a system that measures down to millimeters too good; it is beyond the scope and nature of the game. if it's not visibly out, then it's in. everyone is happy with that, and that is why you MUST have a human-in-the-loop on tennis replays.

OrangePower
12-09-2011, 09:31 PM
it would be just as fast as hawk-eye is now. you can even show the nice fancy 3D video for the audience and commentators, but let there be one judge in a booth that watches the video feeds. let him instantly plays back points to make the "official" call when a player challenges.

If you've ever watched the replay system in action in football (american), then you know how excruciatingly long it takes for humans to review camera footage from various angles in the event of a challenge. Tennis has become slow enough as it is. Hawk-eye isn't too bad in the sense that you get a decision pretty quickly. Having an official watch the video replays from various angles would be slow death.

nousername
12-09-2011, 09:32 PM
If it were actual video, there would still be the human element of subjectiveness as to actually at what exact point contact was made with the ball and the ground.
yes, and no.

actually, hawk-eye makes all kind of assumptions about the ball such as it's elasticity, the thickness of the felt, how much it compresses on impact, etc. it also has to map out the lines of the court, which it could be wrong about. hawk-eye then does some cool estimation stuff to put the ball on their court. that the point it's accurate to millimeters in hawk-eye's digital version of the court. it's not like the 3D trajectory get's over laid on the real court, the court itself is an estimate.

nothing is more accurate than looking at a dang picture/video of the ball landing on the court. in a picture both the ball and the court are REAL.

there are so many source of potential error, that a human watching high-speed video can make a much better call (not necessarily a "more precise" call in terms of distance in or out), but a "better" call that is inline with the essence of tennis.

tennis is a game of honor, and i think the calls should be in the hands of a human.

OddJack
12-09-2011, 09:33 PM
it IS accurate. that's one of my other issues with it. it is too accurate for the game, it defeats the essence of the game.

tennis is generally an "gentleman's" game, it's always been based on honor. at all levels (except the pros) you make your own calls. the challenges would sit better with everyone, esp players and fans, if the actual video was used. in general the rule of tennis is "if you can't tell it's out, then it's in". a system that measures down to millimeters too good; it is beyond the scope and nature of the game. if it's not visibly out, then it's in. everyone is happy with that, and that is why you MUST have a human-in-the-loop on tennis replays.

Yes that's gentleman's game, but unfortunately Ms. Serena Williams plays it too, which is who started it all.

There are too much of controversies, conspiracy theories, racial claims not to mention Money involved to leave it to gentlemanly procedures alone to decide the fate of the match.

Expect to see it in soccer too. Blatter finally gave in to demands for Goal line technology for world cup 2014.

Bobby Jr
12-09-2011, 09:34 PM
The Hawkeye system is pretty good for what it is intended for. It resolved line-call disputes quickly and fairly (as far as we can tell) but the other really good aspect of it is statistics calculating. The stats they derive from it such as average return point position, serve placement, height over net etc etc are fantastic additions to the entertainment package.

I do agree in some ways though, and have said here in the past, that they should call the Hawkeye company's bluff and say they're going to also use high speed cameras at a future event to see whether the claimed accuracy levels are as claimed. I've seen, in the early days of Hawkeye, footage of a line-call which suggested the Hawkeye estimation was as much as 15cm wrong. (it was a straight on call so almost no side-ways blur with most conventional footage).

nousername
12-09-2011, 09:36 PM
If you've ever watched the replay system in action in football (american), then you know how excruciatingly long it takes for humans to review camera footage from various angles in the event of a challenge. Tennis has become slow enough as it is. Hawk-eye isn't too bad in the sense that you get a decision pretty quickly. Having an official watch the video replays from various angles would be slow death.
don't you remember the mac cam? it's was quick and instant. it's be the same way.

tennis is not like the NFL. in tennis the only issue is where the ball hit, period. the ball is relatively unobstructed the whole time, just 2 people and a net. in the NFL it is 22 guys plus 7 refs AND more importantly the NFL is plagued by rules. most replay time is discussion of the rules (i'm guessing).

TTMR
12-09-2011, 09:51 PM
yes, and no.

actually, hawk-eye makes all kind of assumptions about the ball such as it's elasticity, the thickness of the felt, how much it compresses on impact, etc. it also has to map out the lines of the court, which it could be wrong about. hawk-eye then does some cool estimation stuff to put the ball on their court. that the point it's accurate to millimeters in hawk-eye's digital version of the court. it's not like the 3D trajectory get's over laid on the real court, the court itself is an estimate.

nothing is more accurate than looking at a dang picture/video of the ball landing on the court. in a picture both the ball and the court are REAL.

there are so many source of potential error, that a human watching high-speed video can make a much better call (not necessarily a "more precise" call in terms of distance in or out), but a "better" call that is inline with the essence of tennis.

tennis is a game of honor, and i think the calls should be in the hands of a human.

As if player and umpire wouldn't argue over the same shot in a video still. I'm no physicist, but I suspect hawkeye has all kinds of technical advantages over video that we are not even considering.

jokinla
12-09-2011, 10:14 PM
If you've ever watched the replay system in action in football (american), then you know how excruciatingly long it takes for humans to review camera footage from various angles in the event of a challenge. Tennis has become slow enough as it is. Hawk-eye isn't too bad in the sense that you get a decision pretty quickly. Having an official watch the video replays from various angles would be slow death.

Not to mention, this would be used as gamesmanship for sure. You can imagine, a big point, a player would challenge, knowing it would take several minutes to sort it out, in the mean time, killing a bit of momentum, or perhaps giving a player, several much needed minutes to rest, and anything that took that long could never be used between first and second serves, it would never work.

slickerthansleek
12-10-2011, 04:45 AM
Have you ever watched a rugby league game? The way that we look at replays time and time again from all these different angles to figure out whether a try has been scored or not is a pain, and a real momentum killer. For every one or two points hawk-eye screws up, we get a fair result on a thousand of them. So I'm not too bothered, I'd rather hawk-eye get one wrong every now and again than get all of them exactly right but have a system in place which kills the flow of the game.

Bobby Jr
12-10-2011, 05:34 AM
Have you ever watched a rugby league game? The way that we look at replays time and time again from all these different angles to figure out whether a try has been scored or not is a pain, and a real momentum killer. For every one or two points hawk-eye screws up, we get a fair result on a thousand of them.
Yeah, the momentum killer aspect in league is all-but irrelevant if someone has scored as they'd spend 2 mins doing the conversion attempt anyway. If not, they still have to re-set for a goal drop-out or restart which is quicker, but usually a fair bit of time still gets eaten up regardless.

The thing which is interesting about league video refs is they still manage to get piles of video ref calls wrong - often on benefit of doubt calls or obstruction in the preceding phase to a supposed scoring. Plenty of refereeing bias still exists in that system too - you only have to view any number of calls against the Warriors to see that.

The area where league has really improved it's game management is the two ref system in the past 2 years (or is it 3?) and I agree totally... the positives of Hawkeye in tennis probably outweigh any failings in the system by more than 100:1.

Crisstti
12-10-2011, 05:47 AM
it IS accurate. that's one of my other issues with it. it is too accurate for the game, it defeats the essence of the game.

tennis is generally an "gentleman's" game, it's always been based on honor. at all levels (except the pros) you make your own calls. the challenges would sit better with everyone, esp players and fans, if the actual video was used. in general the rule of tennis is "if you can't tell it's out, then it's in". a system that measures down to millimeters too good; it is beyond the scope and nature of the game. if it's not visibly out, then it's in. everyone is happy with that, and that is why you MUST have a human-in-the-loop on tennis replays.

I see your point, hadn't thought about that. It does have many advantages too though. It's quick (not killing the flow of the game, which is the main argument for not having replays in football) , it's entertaining to the audience, everyone can see the replay.

Still think that the umpire checking the actual ball print on clay is better, so I don't see the need for hawk eye there...

yes, and no.

actually, hawk-eye makes all kind of assumptions about the ball such as it's elasticity, the thickness of the felt, how much it compresses on impact, etc. it also has to map out the lines of the court, which it could be wrong about. hawk-eye then does some cool estimation stuff to put the ball on their court. that the point it's accurate to millimeters in hawk-eye's digital version of the court. it's not like the 3D trajectory get's over laid on the real court, the court itself is an estimate.

nothing is more accurate than looking at a dang picture/video of the ball landing on the court. in a picture both the ball and the court are REAL.

there are so many source of potential error, that a human watching high-speed video can make a much better call (not necessarily a "more precise" call in terms of distance in or out), but a "better" call that is inline with the essence of tennis.

tennis is a game of honor, and i think the calls should be in the hands of a human.

Didn't know that about the estimation of the court itself :|

Yes that's gentleman's game, but unfortunately Ms. Serena Williams plays it too, which is who started it all.

There are too much of controversies, conspiracy theories, racial claims not to mention Money involved to leave it to gentlemanly procedures alone to decide the fate of the match.

Expect to see it in soccer too. Blatter finally gave in to demands for Goal line technology for world cup 2014.

I think the goal line issue is one of the least problems, really. Some kind of replay for certain situations - penalties, red card offenses, goals disallowed for off-side - are way more necessary. After all one gets a goal line controversy once every 5 years or more, while the other situations happen all the time.

Have you ever watched a rugby league game? The way that we look at replays time and time again from all these different angles to figure out whether a try has been scored or not is a pain, and a real momentum killer. For every one or two points hawk-eye screws up, we get a fair result on a thousand of them. So I'm not too bothered, I'd rather hawk-eye get one wrong every now and again than get all of them exactly right but have a system in place which kills the flow of the game.

Good point.

mellowyellow
12-10-2011, 08:41 AM
I think what bothers me the most, is that the system surely knows when balls are in or out in real time, why do the challenges even need to be made? I am not saying to totally rely on the system, but you have to wonder why should someone have to risk stoping a point to challenge when the eye already knows in or out? This could be visually done with a green and red light on the net post out of main visibility, and on the refs little computer.

Manus Domini
12-11-2011, 01:54 PM
http://www.youtube.com/watch?v=E5-abgnmGIU

/End thread

Zildite
12-11-2011, 02:03 PM
I think what bothers me the most, is that the system surely knows when balls are in or out in real time, why do the challenges even need to be made? I am not saying to totally rely on the system, but you have to wonder why should someone have to risk stoping a point to challenge when the eye already knows in or out? This could be visually done with a green and red light on the net post out of main visibility, and on the refs little computer.

So line judges would become obsolete? Unless you really did hide it well.
Does it even work that quickly, I don't know.

TTMR
12-11-2011, 07:19 PM
I think what bothers me the most, is that the system surely knows when balls are in or out in real time, why do the challenges even need to be made? I am not saying to totally rely on the system, but you have to wonder why should someone have to risk stoping a point to challenge when the eye already knows in or out? This could be visually done with a green and red light on the net post out of main visibility, and on the refs little computer.

Linespeople are probably unionized, so it won't happen. It is like having an electronic strike zone in MLB; it would completely eliminate the often random and inconsistent strike-calling of umpires, but the umpire union is drastically opposed because a large percentage of officials would be rendered redundant.

pudelko
12-11-2011, 07:45 PM
I think what bothers me the most, is that the system surely knows when balls are in or out in real time, why do the challenges even need to be made? I am not saying to totally rely on the system, but you have to wonder why should someone have to risk stoping a point to challenge when the eye already knows in or out? This could be visually done with a green and red light on the net post out of main visibility, and on the refs little computer.

Ive often thought about this myself. Even if its not real time, its definitely fast enough for the players to just wait a second or two (towel off?) between points to see the result of a questionable shot.

Often times on TV when a player decides not to challenge the TV station shows what hawkeye would have shown anyway, so its seems safe to assume that the feature is available for all shots and the whole challenge thing with the dramatic sound effects and the umpire asking for a challenge is just there for the entertainment of the crowd. Not to mention all the extra time this takes.

Tournaments that dont have hawkeye should fire all linespeople they have now and use that money to install the hawkeye system. :twisted:

OddJack
12-11-2011, 07:51 PM
I think the goal line issue is one of the least problems, really. Some kind of replay for certain situations - penalties, red card offenses, goals disallowed for off-side - are way more necessary. After all one gets a goal line controversy once every 5 years or more, while the other situations happen all the time.




The goal line problem is less frequent, and that's why they are starting off with that. There has been some stubborn resistance to use technology in soccer so this, if it happens, is a significant change.
In one of the last world cup matches the ball had clearly passed the line completely and yet it was overlooked.

Bartelby
12-11-2011, 08:03 PM
Linespeople are usually volunteers or in casual employment, at best, so hardly unionized.


Linespeople are probably unionized, so it won't happen. It is like having an electronic strike zone in MLB; it would completely eliminate the often random and inconsistent strike-calling of umpires, but the umpire union is drastically opposed because a large percentage of officials would be rendered redundant.

Crisstti
12-11-2011, 08:34 PM
The goal line problem is less frequent, and that's why they are starting off with that. There has been some stubborn resistance to use technology in soccer so this, if it happens, is a significant change.
In one of the last world cup matches the ball had clearly passed the line completely and yet it was overlooked.

Well, that was just karma ;)

nousername
12-13-2011, 08:16 AM
As if player and umpire wouldn't argue over the same shot in a video still. I'm no physicist, but I suspect hawkeye has all kinds of technical advantages over video that we are not even considering.
two key points that you, and many others, are missing:

1) these are HIGH SPEED video cameras, i.e. probably 1000 frames per second. There will almost never be a disagreement with that kind of time resolution. it's not a matter of one low-res image that may or may not have been snapped at the right time.

2) there are 12 camera angles available to choose from. and tennis is NOT football or rugby, there's not clutter or obscurity of events. you have 12 angles to see ONE ball on a large open high contrast area. AND you won't need all 12 one time. with experience the umps will know exactly which of the 12 to choose for any one review. you would only need to look at 1 or 2 angles for a given shot.

if you guys will take time to dwell on these facts you will come around. hawk-eye is an unnecessary element of the game. hawk-eye is a business and want to sell an awesome product. i love hawk-eye as a technology, but they've conned tennis. tennis needs their camera setup but not their 3D processing.

Lsmkenpo
12-13-2011, 08:37 AM
The one flaw with hawkeye is it uses a 3d model of the court, that is fine on a hardcourt which doesn't change but on a natural surface it is not as accurate. The court level is not completely flat on grass or clay and doesn't remain constant.

woodrow1029
12-13-2011, 08:47 AM
two key points that you, and many others, are missing:

1) these are HIGH SPEED video cameras, i.e. probably 1000 frames per second. There will almost never be a disagreement with that kind of time resolution. it's not a matter of one low-res image that may or may not have been snapped at the right time.

2) there are 12 camera angles available to choose from. and tennis is NOT football or rugby, there's not clutter or obscurity of events. you have 12 angles to see ONE ball on a large open high contrast area. AND you won't need all 12 one time. with experience the umps will know exactly which of the 12 to choose for any one review. you would only need to look at 1 or 2 angles for a given shot.

if you guys will take time to dwell on these facts you will come around. hawk-eye is an unnecessary element of the game. hawk-eye is a business and want to sell an awesome product. i love hawk-eye as a technology, but they've conned tennis. tennis needs their camera setup but not their 3D processing.

I don't see how a system that has been proven to be accurate to around 1 millimeter, helps the officials get the call right, removes subjectivity on a very, very, very close call, and keeps the matches moving without argument from the players is a con.

j00dypoo
12-13-2011, 09:02 AM
nousername is failing to take his own advice and "dwell on the facts." All the great points have already been made against you.

1) can't stop tennis matches and review 12 camera angles and take 2 minutes to make a line call. Hawkeye resolves the matter quickly and efficiently.

2) gives an ultimate answer. No human subjectivity involved which is great. You can't argue with a computer. It's like hitting against a wall - you will always lose.

3) It is accurate. It's been proven accurate and it's only going to improve.

Lsmkenpo
12-13-2011, 09:10 AM
"According to the ITF criteria, any electronic line-calling system must be able to judge a ball in or out within 5 millimeters (0.20 inches). Incorrect calls are allowed, so long as they are not more than 10 millimeters (0.40 inches) off." :shock:

http://sports.espn.go.com/sports/tennis/wimbledon08/news/story?id=3452293 Two British scientists call into question Hawk-Eye's accuracy

LuckyR
12-13-2011, 09:16 AM
also, in those close calls where Hawk eye calls it out or in by a matter of millimeters. in those situations, it would be much better for everyone fans, players, umpires, etc. to see the 12 video fees in high-speed, and then let the ump make a judgment call. everyone would be happy with that. tennis is kind of based on the honor system, ALL calls should ultimately be based on a human's judgment rather than some overly technical digital system.

the system as used is a joke.

You clearly don't get it. The whole point of Hawkeye is to get an objective measure. Some things can't be known absolutely, most people can wrap their minds around that reality. What is truly unreliable is a person making a "judgement call", since people (unlike a computer averaging 12 images), have their biases.

As to having an immediate answer instead of having everyone in the crowd look up at a screen and see the image in slo mo, you obviously aren't in charge of selling tickets, since it is a large crowd pleaser.

Lsmkenpo
12-13-2011, 09:18 AM
nousername is failing to take his own advice and "dwell on the facts." All the great points have already been made against you.

1) can't stop tennis matches and review 12 camera angles and take 2 minutes to make a line call. Hawkeye resolves the matter quickly and efficiently.

2) gives an ultimate answer. No human subjectivity involved which is great. You can't argue with a computer. It's like hitting against a wall - you will always lose.

3) It is accurate. It's been proven accurate and it's only going to improve.

Point number three is highly debatable, hawkeye's average margin of error is 3.6mm, some may say that is not exactly accurate, hawkeye is not a real measurement , it is a model of what may have happened.

pennc94
12-13-2011, 09:18 AM
I think what bothers me the most, is that the system surely knows when balls are in or out in real time, why do the challenges even need to be made? I am not saying to totally rely on the system, but you have to wonder why should someone have to risk stoping a point to challenge when the eye already knows in or out? This could be visually done with a green and red light on the net post out of main visibility, and on the refs little computer.

^^^^
I have been saying this for years.

Drop the need for players to decide whether or not to challenge. They should be focused on the tennis (not deciding if a linesman makes an error).

In addition to the red/green light, I suggest connecting a speaker that proclaims "OUT". I vote to have it use the voice of James Earl Jones.

Lsmkenpo
12-13-2011, 09:29 AM
^^^^^^^^^^

Hawkeye doesn't work that way, it is a statistical model of what may have happened on court calculating the balls trajectory, not a real time measurement of the actual shot. It is an accurate guesstimate.

pennc94
12-13-2011, 09:33 AM
^^^^^^^^^^

Hawkeye doesn't work that way, it is a statistical model of what may have happened on court calculating the balls trajectory, not a real time measurement of the actual shot. It is an accurate guesstimate.

Agreed it has its limitations (not being 100% accurate), but it appears it might get things more right than wrong as compared to the human eye. Has that comparison ever been made?

Let's say that its margin of error is 4 mm. Then call LET when the mark (as estimated by Hawkeye) is within the margin of error.

Magnetite
12-13-2011, 09:39 AM
One of the worst ideas ever.

I don't see Hawkeye making terrible calls, but I saw lines people make terrible calls all the time.

Umpires would also make terrible calls, and players would blow up. The player that got ripped off would then be too angry to play and tank the match.

Terrible idea.

nousername
12-13-2011, 09:42 AM
You clearly don't get it. The whole point of Hawkeye is to get an objective measure. Some things can't be known absolutely, most people can wrap their minds around that reality. What is truly unreliable is a person making a "judgement call", since people (unlike a computer averaging 12 images), have their biases.

As to having an immediate answer instead of having everyone in the crowd look up at a screen and see the image in slo mo, you obviously aren't in charge of selling tickets, since it is a large crowd pleaser.
i respectfully disagree, and it seems you are confused about the definition of being "objective".

an ump making the call is an objective decision just like hawk-eye. they both base their decision on an interpretation of facts. the ump uses a visual image in his brain, whereas hawk-eye uses a visual image in a computer. the only difference is the amount of uncertainty in each process. both have uncertainty, but at different levels. (subjective is like "is wheat bread tastier than white bread?" that's a personal decision. it has a subjective answer.)

my argument is that tennis is a human sport so it should be based on an observation and judgement made at an objective human level.

hawk-eye defeats the purpose of the game. it's like looking at tennis through a microscope.

hawk-eye in tennis is like tracking which blades of grass are white and which are green in football/soccer/rugby for the purpose of determining if a player is out-of-bounds by zooming into each footstep at a magnification of 1000x to see if a single white blade of grass may or may not have touched his foot. that would be ludicrous, so is hawk-eye in tennis.

or it would be like if i asked you what's the answer to:

1.234 * 5.678

and you told me:

7.00665200000000000000

when anything beyond 7.007 is irrelevant. that is hawk-eye in tennis.

woodrow1029
12-13-2011, 09:42 AM
Agreed it has its limitations (not being 100% accurate), but it appears it might get things more right than wrong as compared to the human eye. Has that comparison ever been made?

Let's say that its margin of error is 4 mm. Then call LET when the mark (as estimated by Hawkeye) is within the margin of error.

If its margin of error was 4 mm, it would never be used in professional tennis.

Magnetite
12-13-2011, 09:44 AM
^^^^
I have been saying this for years.

Drop the need for players to decide whether or not to challenge. They should be focused on the tennis (not deciding if a linesman makes an error).

In addition to the red/green light, I suggest connecting a speaker that proclaims "OUT". I vote to have it use the voice of James Earl Jones.

This would work well, although unlike what others have said, you would still have to keep lines people in case their was a malfunction.

nousername
12-13-2011, 09:44 AM
One of the worst ideas ever.

I don't see Hawkeye making terrible calls, but I saw lines people make terrible calls all the time.

Umpires would also make terrible calls, and players would blow up. The player that got ripped off would then be too angry to play and tank the match.

Terrible idea.
an umpire would make terrible calls if he had 12 camera angles at 1000 frames/second at his disposal????

Magnetite
12-13-2011, 09:45 AM
an umpire would make terrible calls if he had 12 camera angles at 1000 frames/second at his disposal????

Yes.

He's human. Under pressure situations, he may get stressed and rush his decision. It happens all the time, and would take too long anyway.

pennc94
12-13-2011, 09:46 AM
One of the worst ideas ever.

I don't see Hawkeye making terrible calls, but I saw lines people make terrible calls all the time.

Umpires would also make terrible calls, and players would blow up. The player that got ripped off would then be too angry to play and tank the match.

Terrible idea.

I am not sure you understand what I wrote.

I am FOR the Hawkeye or any computer line calling system (because it appears to be an improvement over the human eye)
I am NOT FOR the challenge system (because it keeps players from focusing on just tennis).

However, since Hawkeye has some measure of inaccuracy (as small as it may be) it should be addressed (unless players are willing to accept the stated margin of error).

If the line-calling by Hawkeye is instantaneous, then linesmen should be eliminated and have Hawkeye make all calls. Keep the umpire for other rule enforcement.

j00dypoo
12-13-2011, 09:58 AM
my argument is that tennis is a human sport so it should be based on an observation and judgement made at an objective human level.


well of course tennis is a human sport - robots don't play it (well maybe in japan but I haven't seen it yet). Those two points have absolutely no relation to each other.

Cars are purely mechanical machines, so only mechanical machines should operate them.

Also, even if the average margin of error were 3.6 mm (where did you find this btw), that's such a small margin and much better than any human could ever hope to achieve. Seriously, take out a ruler and measure out 3.6 mm. How could anyone, even using high speed cameras, hope to get a better measurement and judgement call in as short a time as hawkeye is able to produce?

nousername
12-13-2011, 10:02 AM
Yes.

He's human. Under pressure situations, he may get stressed and rush his decision. It happens all the time, and would take too long anyway.
perhaps, but i doubt it.

to me, the one argument for hawk-eye is the speed of decision. it does comeback quick with an answer. but with the proper setup, e.g. for a trivial cost (in the grand scheme of an ATP event) adding monitors to all umps' chairs would make video reviews quick.

Lsmkenpo
12-13-2011, 10:08 AM
If its margin of error was 4 mm, it would never be used in professional tennis.

From the link to the article I posted earlier in the thread, Paul Hawkins, managing director of Hawk-Eye technology states hawkeye's average margin of error is 3.6mm.

The ITF rulebook also states an electronic line calling device can be used as long as it is accurate within 10mm.

woodrow1029
12-13-2011, 10:19 AM
From the link to the article I posted earlier in the thread, Paul Hawkins, managing director of Hawk-Eye technology states hawkeye's average margin of error is 3.6mm.

The ITF rulebook also states an electronic line calling device can be used as long as it is accurate within 10mm.

That article is from quite a while ago. Since then, the technology has improved and the margin of error is around 1-2 mm.

The ITF rulebook does not state that at all.

woodrow1029
12-13-2011, 10:22 AM
And you are right, at that time the margin of error was 3.6 mm, but after a lot of complaints, if the technology did not improve, it would not have continued to be used until it got better. 4 mm is a lot, especially in certain times of a match.

Lsmkenpo
12-13-2011, 10:25 AM
That article is from quite a while ago. Since then, the technology has improved and the margin of error is around 1-2 mm.

The ITF rulebook does not state that at all.

Than the information in the article is wrong, what is the official ITF criteria regarding the permissible error of the line calling system at the present time,
do you happen to know off hand?

woodrow1029
12-13-2011, 10:26 AM
Than the information in the article is wrong, what is the official ITF criteria regarding the permissible error of the line calling system at the present time,
do you happen to know off hand?

In the ITF rulebook, there is nothing that states a permissible margin of error for an electronic review system.

woodrow1029
12-13-2011, 10:28 AM
This quote from that article was the best line back in 2008, "
Collins and Evans said that while what Hawk-Eye achieves is remarkable, its use in tennis needs to be refined."

That was true then, because the players and officials were not happy with a margin of error so big.

nousername
12-13-2011, 10:41 AM
well of course tennis is a human sport - robots don't play it (well maybe in japan but I haven't seen it yet). Those two points have absolutely no relation to each other.

Cars are purely mechanical machines, so only mechanical machines should operate them.

Also, even if the average margin of error were 3.6 mm (where did you find this btw), that's such a small margin and much better than any human could ever hope to achieve. Seriously, take out a ruler and measure out 3.6 mm. How could anyone, even using high speed cameras, hope to get a better measurement and judgement call in as short a time as hawkeye is able to produce?
don't understand your argument about cars and robots. by "human" i'm referring to scale. for example, imagine you give directions for a friend to come to your place and they are coming by car. does it make sense to say:

A) drive 123 meters and 4.5 centimeters and make a right turn, OR
B) drive 120 meters and make a right turn

which makes more sense and is most applicable?

yes, i could put an ultra-precise differential RTK GPS system on your friend's car that would tell you their position within a couple centimeters, but does it make sense for the task at hand, i.e. of getting the information to your friend about when the next turn is going to happen?

of course not.

in tennis, we live by the courtesy rule of:

if it's too close to call, then it's in

i think (in my subjective opinion) tennis should have a replay system that lives up to that standard but not better.

of course a human won't be able to see 3.6 mm of error, but if a high speed video shows, from a non-zoomed in view, it was "too close to call it out", then the ball should be good.

so when hawk-eye calls a ball out by 1mm, and even if the ball really was out by 1mm, there is no way a human would ever call that ball out if they saw a replay of it. a ball out by 1mm should be good.

Lsmkenpo
12-13-2011, 10:42 AM
This quote from that article was the best line back in 2008, "
Collins and Evans said that while what Hawk-Eye achieves is remarkable, its use in tennis needs to be refined."

That was true then, because the players and officials were not happy with a margin of error so big.

Do you think it is just as accurate on natural surfaces as it is on hardcourt.

From my understanding it uses a computer model of the court, but a natural surface can changes ever so slightly during play, I recall reading this small change from the model to reality can make it slightly less accurate on clay versus hard and is one of the reasons why they don't use it on clay, Have you heard anything about this?

LuckyR
12-13-2011, 10:49 AM
i respectfully disagree, and it seems you are confused about the definition of being "objective".

an ump making the call is an objective decision just like hawk-eye. they both base their decision on an interpretation of facts. the ump uses a visual image in his brain, whereas hawk-eye uses a visual image in a computer. the only difference is the amount of uncertainty in each process. both have uncertainty, but at different levels. (subjective is like "is wheat bread tastier than white bread?" that's a personal decision. it has a subjective answer.)

my argument is that tennis is a human sport so it should be based on an observation and judgement made at an objective human level.

hawk-eye defeats the purpose of the game. it's like looking at tennis through a microscope.

hawk-eye in tennis is like tracking which blades of grass are white and which are green in football/soccer/rugby for the purpose of determining if a player is out-of-bounds by zooming into each footstep at a magnification of 1000x to see if a single white blade of grass may or may not have touched his foot. that would be ludicrous, so is hawk-eye in tennis.

or it would be like if i asked you what's the answer to:

1.234 * 5.678

and you told me:

7.00665200000000000000

when anything beyond 7.007 is irrelevant. that is hawk-eye in tennis.

The players (who are getting paid based on these decisions after all) are familiar with a human being (even an umpire!!) having a bias. Computer programs don't discriminate between individuals.

As to your highlit sentance, I have no idea what it means, from a practical viewpoint. But if the players like the unbiased aspect and the crowds love the anticipation in real time, whom else's opinion matters?

woodrow1029
12-13-2011, 10:50 AM
The players (who are getting paid based on these decisions after all) are familiar with a human being (even an umpire!!) having a bias. Computer programs don't discriminate between individuals.

As to your highlit sentance, I have no idea what it means, from a practical viewpoint. But if the players like the unbiased aspect and the crowds love the anticipation in real time, whom else's opinion matters?

By bias, you are meaning mistakes in line calls, not bias as in lack of impartiality towards certain players right?

LuckyR
12-13-2011, 10:57 AM
By bias, you are meaning mistakes in line calls, not bias as in lack of impartiality towards certain players right?

I mean the appearance of partiality. I don't honestly believe (outside of Davis Cup) that intentional bias exists in tennis. But just because I may be correct doesn't mean that there isn't the idea of intentional bias in the minds of players who are making their living off of these calls. The well established fact of unintentional bias is another whole subject that is perhaps beyond the scope of this Forum, but is a reality also.

Regardless, Hawkeye gets around all of this and is a crowd pleaser too. No brainer --> good for the sport.

woodrow1029
12-13-2011, 11:03 AM
I mean the appearance of partiality. I don't honestly believe (outside of Davis Cup) that intentional bias exists in tennis. But just because I may be correct doesn't mean that there isn't the idea of intentional bias in the minds of players who are making their living off of these calls. The well established fact of unintentional bias is another whole subject that is perhaps beyond the scope of this Forum, but is a reality also.

Regardless, Hawkeye gets around all of this and is a crowd pleaser too. No brainer --> good for the sport.

I don't think that the players believe there is an intentional bias against them (outside of maybe Davis Cup). This idea might have existed 20-30 years ago when the officiating was not at the level it is today, but now that at Davis Cup, Fed Cup, Olympics, Grand Slams and most Masters Series events, a chair umpire is not allowed to umpire a match with a player from his/her own country, and the line umpires just don't make calls based on where a player is from. It's just mistakes, and I don't see the players having that mindset of impartiality either now.


But I agree, it's a crowd pleaser and makes the matches run more smoothly. So it's a good thing for the sport definitely.

SandV
12-13-2011, 11:16 AM
That article is from quite a while ago. Since then, the technology has improved and the margin of error is around 1-2 mm.

The ITF rulebook does not state that at all.


Noooo, right before the 2011 Aus Open, promotional coverage featured an article quoting the 3.6 mm figure as the margin of error during use at the 2010 Aus Open.

LuckyR
12-13-2011, 11:19 AM
I don't think that the players believe there is an intentional bias against them (outside of maybe Davis Cup). This idea might have existed 20-30 years ago when the officiating was not at the level it is today, but now that at Davis Cup, Fed Cup, Olympics, Grand Slams and most Masters Series events, a chair umpire is not allowed to umpire a match with a player from his/her own country, and the line umpires just don't make calls based on where a player is from. It's just mistakes, and I don't see the players having that mindset of impartiality either now.


But I agree, it's a crowd pleaser and makes the matches run more smoothly. So it's a good thing for the sport definitely.

Even if what you are saying is absolutely correct and I don't have anything except human nature to dispute it, your commentary misses the very real issue of unintentional bias. But as we agreed, Hawkeye does address it.

sureshs
12-13-2011, 11:20 AM
How long would it take for the umpire to watch 12 videos and make a decision?

j00dypoo
12-13-2011, 11:21 AM
nousername, we're obviously on completely different pages here. no argument either of us makes will make an impact on the other.

Your directions and gps argument also has no bearing on this conversation. Tennis is a game played between the lines (and on them...) and is a precise game. There are absolutes in tennis and hawkeye is the most efficient way of handling them. Driving directions are not a game, do not have to be so precise, and have other distinctions like "go 4 lights and take a right." Completely no relation to tennis.

sureshs
12-13-2011, 11:21 AM
my argument is that tennis is a human sport so it should be based on an observation and judgement made at an objective human level.


Murder is also a human activity but microscopic DNA analysis is used in forensics.

Lsmkenpo
12-13-2011, 11:24 AM
How long would it take for the umpire to watch 12 videos and make a decision?

Less than the time it takes for Nadal to serve.

sureshs
12-13-2011, 11:24 AM
or it would be like if i asked you what's the answer to:

1.234 * 5.678

and you told me:

7.00665200000000000000

when anything beyond 7.007 is irrelevant. that is hawk-eye in tennis.

No, for that you have to analyze the precision of the input and output data in Hawk Eye and work out confidence intervals. These things are not debated with arguments like yours. You have to use the data relevant to the system, not your own inventions.

Pwned
12-13-2011, 11:30 AM
I think hawkeye can be wrong sometimes but I don't think the problem is with the rendering they choose to display. The cameras are used by a computer to triangulate the exact position and flight of the ball. The rendering also shows the ball mark. It is probably also a lot clearer than the actual footage would be. Using many cameras and a computer > using 1 slow motion video playback. I doubt the computer is fubaring the accuracy when it renders the footage.

woodrow1029
12-13-2011, 11:33 AM
I think hawkeye can be wrong sometimes but I don't think the problem is with the rendering they choose to display. The cameras are used by a computer to triangulate the exact position and flight of the ball. The rendering also shows the ball mark. It is probably also a lot clearer than the actual footage would be. Using many cameras and a computer > using 1 slow motion video playback. I doubt the computer is fubaring the accuracy when it renders the footage.

Also with cameras, is that there is the possibility of getting the wrong foot. It used to happen with Mac Cam every now and then. I remember in the Hewitt vs. Sampras final at the U.S. Open, Sampras was at the net and there was a close baseline call on his end. When the showed the Mac Cam replay, there were feet in the video, and they were obviously not Sampras' feet.

With Hawkeye, tehre is still the chance that the wrong shot could be selected, but you don't have to rewind and fast forward and waste a lot of time. There is a screen that shows the last 5 shots in the rally marked by numbers 1-5 with 1 being the most recent. The umpire in the review booth selects which shot is being challenged (99% of the time it is either shot 1 or 2), and that is the shot that is shown.

Lsmkenpo
12-13-2011, 11:44 AM
No, for that you have to analyze the precision of the input and output data in Hawk Eye and work out confidence intervals. These things are not debated with arguments like yours. You have to use the data relevant to the system, not your own inventions.

While your at it can you proof this for me?

Prove that the non trivial zeros of the Riemann Zeta-function lie on the critical line 1/2 + it

sureshs
12-13-2011, 11:45 AM
While your at it can you proof this for me?

Prove that the non trivial zeros of the Riemann Zeta-function lie on the critical line 1/2 + it

Catherine Zeta-Jones

mellowyellow
12-13-2011, 02:31 PM
From the link to the article I posted earlier in the thread, Paul Hawkins, managing director of Hawk-Eye technology states hawkeye's average margin of error is 3.6mm.

The ITF rulebook also states an electronic line calling device can be used as long as it is accurate within 10mm.
That was probably grandfathered in for cyclops serve calling from long ago. If that system was instantaneous, why isn't HE instantaneous........ I think reasonable expectation from an elecronic line calling system in this day and age of optics/electronics when implemented in a sport, are for it to be accurate, and quick. HE has accomplished none of this. Its not accurate, we have seen replays of balls that were clearly not what HE replayed. It is also not quick, everytime someone challenge a first serve, it takes so long if they were right anyway you should get another 1 serve. I do not want to see human line calling be done away with. It would take away from the game as has been the case with no net judge.

woodrow1029
12-13-2011, 02:43 PM
That was probably grandfathered in for cyclops serve calling from long ago. If that system was instantaneous, why isn't HE instantaneous........ I think reasonable expectation from an elecronic line calling system in this day and age of optics/electronics when implemented in a sport, are for it to be accurate, and quick. HE has accomplished none of this. Its not accurate, we have seen replays of balls that were clearly not what HE replayed. It is also not quick, everytime someone challenge a first serve, it takes so long if they were right anyway you should get another 1 serve. I do not want to see human line calling be done away with. It would take away from the game as has been the case with no net judge.

First of all, thank god they did away with the net judge. That was the most dangerous place to be on the court, and I had my bell rung once by a Davenport return, and it was not fun. Granted, when you're not being hit, it's the best seat in the house though! :-) Some places do use a net judge still though, not many.

Hawkeye is very accurate. Cyclops did not have a 4 mm margin of error either. The reason Cyclops was instantaneous is because it was simply an infrared beam that went across the court and beeped as soon as the ball went through the beam. The obvious problem was that it could only be used on the service line, and when it was a doubles match, the service line had to use headphones because the receiver's partner triggered the beep when their feet went through the beam.

sureshs
12-13-2011, 02:52 PM
Bury touch-sensitive miniature sensors under the court and use them to register with a central station when a ball or person or frame touches them - then use cameras to determine the region where it could have been only the ball, and then you know exactly where it landed.

Sort of like making the tennis court into one gigantic touch screen. You can call it iCourt.

You could also extend that to measure ball speeds and spin at bounce.

mellowyellow
12-13-2011, 02:53 PM
First of all, thank god they did away with the net judge. That was the most dangerous place to be on the court, and I had my bell rung once by a Davenport return, and it was not fun. Granted, when you're not being hit, it's the best seat in the house though! :-) Some places do use a net judge still though, not many.

Hawkeye is very accurate. Cyclops did not have a 4 mm margin of error either. The reason Cyclops was instantaneous is because it was simply an infrared beam that went across the court and beeped as soon as the ball went through the beam. The obvious problem was that it could only be used on the service line, and when it was a doubles match, the service line had to use headphones because the receiver's partner triggered the beep when their feet went through the beam.

The problem I have with no net judge, is I know I have heard the beep when the ball crosses the net and point is still played, I have also seen balls served by guys 6'3" or bigger to the back of the box and it be called a let... not flat serves either. Cyclops? Don't really know how to take your post, if you are saying its margin was less than 4mm, that is laughable at best, as i said probably why the margin in the rules is at 10 if it is true.... That rule could also have stated can work at random and must be turned off for half the match.

woodrow1029
12-13-2011, 05:42 PM
The problem I have with no net judge, is I know I have heard the beep when the ball crosses the net and point is still played, I have also seen balls served by guys 6'3" or bigger to the back of the box and it be called a let... not flat serves either. Cyclops? Don't really know how to take your post, if you are saying its margin was less than 4mm, that is laughable at best, as i said probably why the margin in the rules is at 10 if it is true.... That rule could also have stated can work at random and must be turned off for half the match.
Cyclops definitely was accurate to closer than 4 millimeters when it was on a court in ideal conditions.

It did have its issues though.

1. In extreme heat, when the court would bubble up and would cause the beep to go off (unfortunately this would occur during the service motion when the serve line umpire pressed the button on Cyclops) causing a let.

2. Flash Photography would sometimes cause the machine to beep at random times.

The net device is more accurate than you think. And I don't agree that the net device goes off and then the point is still played out. If anything, the problem is that it goes off sometimes during the service motion, and becuase of the sound in the microphone, the entire point is replayed because it's a hindrance. I am not saying that it NEVER happens that the umpire decides not to call a let and the point is played out, but the mistakes are very rare and would not justify doing away with the net machine. I do agree that there are times that Trinity misses lets and calls lets that are not, but it's not often at all.

sundaypunch
12-13-2011, 05:54 PM
Why would they change the Hawkeye system? It seems wildly successful to me. It is quick and TV friendly. It adds a bit of excitement for the audience at the match and at home when calls are challenged. It would be a total buzzkill to have an NFL type system where the umpire had to watch tape replays.

It's never going to be about finding the most accurate system.

InspectorRacquet
12-13-2011, 06:25 PM
The Hawkeye system has no need for change. It's very accurate (more so than subjective high speed video reviews), quick, and most of all, a good representation of the point in question.

Hawkeye takes out the human factor and allows for an unbiased decision to be made without any subjectivity. It makes the game as fair as possible.

mellowyellow
12-13-2011, 06:59 PM
The Hawkeye system has no need for change. It's very accurate (more so than subjective high speed video reviews), quick, and most of all, a good representation of the point in question.

Hawkeye takes out the human factor and allows for an unbiased decision to be made without any subjectivity. It makes the game as fair as possible.

I will agree that most of the time its accurate, but sometimes when its off, its off by a good margin.

Me thinks you should look the definition up, then take a realistic look at the steaming pile they are feeding you :)

Why is DC and FC played with unlimited challenges, but thats not how tournament play is? If you as a player are wrong, they take a challenge away, if you are right and the ump and all the linesman are wrong do you get an extra challenge for being the only one on court thats not simpleton. What is fair about that? Why can't you carry challenges over from the first set? They give them to you because their is a statistical chance of 3 bad calls per set? 9 per 3 set match? If they don't happen in the first set does that mean you can't have 6 in the second or 9 in the third. Who did this research and what was the finding to come to 3 per?

Timbo's hopeless slice
12-13-2011, 07:01 PM
Methinks (it's actually one word) you should stop flogging a dead horse and listen to Woodrow.

If you don't know why, then I can't be bothered explaining it to you as even a cursory bit of research would have done it for you...

sureshs
12-13-2011, 07:12 PM
Methinks (it's actually one word)

Whose usage ended with Shakespeare's time

j00dypoo
12-13-2011, 07:29 PM
this is starting to sound like a certain party's debate

Timbo's hopeless slice
12-13-2011, 08:31 PM
Whose usage ended with Shakespeare's time

lol, well, if mellow is going to use it, he may as well get it right!

by the way, "the usage of which ended etc" would be better grammar... :)

woodrow1029
12-14-2011, 07:11 AM
I will agree that most of the time its accurate, but sometimes when its off, its off by a good margin.

Me thinks you should look the definition up, then take a realistic look at the steaming pile they are feeding you :)

Why is DC and FC played with unlimited challenges, but thats not how tournament play is? If you as a player are wrong, they take a challenge away, if you are right and the ump and all the linesman are wrong do you get an extra challenge for being the only one on court thats not simpleton. What is fair about that? Why can't you carry challenges over from the first set? They give them to you because their is a statistical chance of 3 bad calls per set? 9 per 3 set match? If they don't happen in the first set does that mean you can't have 6 in the second or 9 in the third. Who did this research and what was the finding to come to 3 per?

Davis Cup and Fed Cup are NOT played with unlimited challenges anymore. In 2008 the rules were changed to be uniform for all bodies of professional tennis to three challenges per set and one additional in the tiebreak. In a final set with no tiebreak, the three challenges reset every 12 games.

sundaypunch
12-14-2011, 07:22 AM
I will agree that most of the time its accurate, but sometimes when its off, its off by a good margin.

Me thinks you should look the definition up, then take a realistic look at the steaming pile they are feeding you :)

Why is DC and FC played with unlimited challenges, but thats not how tournament play is? If you as a player are wrong, they take a challenge away, if you are right and the ump and all the linesman are wrong do you get an extra challenge for being the only one on court thats not simpleton. What is fair about that? Why can't you carry challenges over from the first set? They give them to you because their is a statistical chance of 3 bad calls per set? 9 per 3 set match? If they don't happen in the first set does that mean you can't have 6 in the second or 9 in the third. Who did this research and what was the finding to come to 3 per?

You don't hear players complaining about Hawkeye or the challenge system. That in itself says something as they seem to complain about everything else. As for the number of challenges, you don't need statistical information. You agree on a system and then make changes when it becomes apparent that they are needed. Most probably consider three as reasonable since for decades players had zero. Also, if they use them wisely and are correct, technically they are unlimited.

They aren't going to fix a "problem" that doesn't exist.

TennisLovaLova
12-14-2011, 08:55 AM
The vid here isnt about the Hawk eye. It's about bad sportmanship.
THat dude should have told the ref he hit the ball with his leg.

j00dypoo
12-14-2011, 10:29 AM
Another thing we've all forgotten to mention is how Hawkeye allows players to move on from a "bad" call. They can have assurance that either a) yes their ball was indeed out or b) a crappy call was overturned in their favor.

Then they can forget about it and continue playing without a worry.

wilkinru
12-14-2011, 04:06 PM
I'm sure there are times where it is wrong. However it will be wrong for everyone here and there. I've never seen it really wrong before. Sometimes the ball is real close and it calls it in, sometimes calls it out.

In the end the players can just know - it wasnt a human against them making calls. Stupid computer - and move on.

Johnny mac wouldnt have been nearly as interesting these days.

j00dypoo
12-14-2011, 08:01 PM
Johnny mac wouldnt have been nearly as interesting these days.

Maybe, maybe not. He would argue with the umpire about the computer being wrong. That might prove entertaining, as futile as it may be.

mellowyellow
12-15-2011, 02:36 PM
Another thing we've all forgotten to mention is how Hawkeye allows players to move on from a "bad" call. They can have assurance that either a) yes their ball was indeed out or b) a crappy call was overturned in their favor.

Then they can forget about it and continue playing without a worry.
Yet, I have already seen where HE called a ball against and the player is looking at a mark that is telling him/her the opposite. How do you move on from that? The clay has proved that the HE system is pretty solid, but there are still those points where it was not correct as to the mark and the ump ruling. Now who would you trust in that situation?

woodrow1029
12-15-2011, 02:40 PM
Yet, I have already seen where HE called a ball against and the player is looking at a mark that is telling him/her the opposite. How do you move on from that? The clay has proved that the HE system is pretty solid, but there are still those points where it was not correct as to the mark and the ump ruling. Now who would you trust in that situation?

The actual mark on a hardcourt is not a 100% true representation of the full compression of the ball on impact.

j00dypoo
12-15-2011, 04:39 PM
The actual mark on a hardcourt is not a 100% true representation of the full compression of the ball on impact.

+1 to that. plus half the time I bet they choose a mark that fits the situation and benefits themselves. not the actual mark.

dh003i
12-15-2011, 04:47 PM
They should put Hawkeye up during the French Open and other clay-court tournaments to expose how inaccurate it is.

Calls Hawkeye makes that fall within its standard deviation should not overturn anything.

Also, we don't really have any data on the standard deviation of Hawkeye.

AlpineCadet
12-15-2011, 04:48 PM
I want my time back from opening up this thread!

mellowyellow
12-15-2011, 05:29 PM
The actual mark on a hardcourt is not a 100% true representation of the full compression of the ball on impact.
Balls do not flatten on the court like they do on a racquet. Compression on a racquet is from a complete change in direction, therefore major compression of the ball happens. A groundstroke going from one side to the other will simply be a deflection in trajectory, with the spin and pace their is little compression of the ball. The marks on hardcourt are a pretty true representation of where the ball hit the court. Besides most of the time its off a serve or a flat winner that is hard to see to begin with, not a loopy topspin that has a disticnt trajectory and bounce.

adamX012
12-15-2011, 06:41 PM
someone has a thread about the motion of the tennis balls. Using the same type of the camera, isn't.

OddJack
12-15-2011, 07:34 PM
The actual mark on a hardcourt is not a 100% true representation of the full compression of the ball on impact.

Balls do not flatten on the court like they do on a racquet. Compression on a racquet is from a complete change in direction, therefore major compression of the ball happens. A groundstroke going from one side to the other will simply be a deflection in trajectory, with the spin and pace their is little compression of the ball. The marks on hardcourt are a pretty true representation of where the ball hit the court. Besides most of the time its off a serve or a flat winner that is hard to see to begin with, not a loopy topspin that has a disticnt trajectory and bounce.

I think what woodrow meant was " impression", not compression.

The impression on the court is not 100% equal to compression of the ball.

What you say about the difference between ball compression on racket and on court surface is true but irrelevant to the discussion.

You say the marks on hard court are good representation of where the ball hit the court, and I agree.

The impression, or the recreation of impression by hawk eye, is good enough for our purpose imo.

mellowyellow
12-15-2011, 07:52 PM
I think what woodrow meant was " impression", not compression.

The impression on the court is not 100% equal to compression of the ball.

What you say about the difference between ball compression on racket and on court surface is true but irrelevant to the discussion.

You say the marks on hard court are good representation of where the ball hit the court, and I agree.

The impression, or the recreation of impression by hawk eye, is good enough for our purpose imo.
That part of the show doesn't bother me, its the fact the intended purpose is for the show primarily, not the integrity of the game when it is there to be utilized as such.
I think what woodrow was saying is the mark is inaccurate. He was talking actual ball mark not generated. He was saying the ball flattens out more than the mark shows (thats what I took from it), and I believe this to be false, thats why my statement pertains to his statement, though agreed not exactly to the thread. I do not think the HC ball mark to be perfect, but I believe it to be closer than HE +/- margin :)

woodrow1029
12-15-2011, 08:12 PM
Balls do not flatten on the court like they do on a racquet. Compression on a racquet is from a complete change in direction, therefore major compression of the ball happens. A groundstroke going from one side to the other will simply be a deflection in trajectory, with the spin and pace their is little compression of the ball. The marks on hardcourt are a pretty true representation of where the ball hit the court. Besides most of the time its off a serve or a flat winner that is hard to see to begin with, not a loopy topspin that has a disticnt trajectory and bounce.
To say a tennis ball does not compress when it hits the court is just stupid. Of course it will compress more when it hits the racket. But you can't sit there and say it doesn't compress when it hits the court. Hence the elliptical shape of ball marks and the much wider ball marks on like an overhead than a dropshot.

woodrow1029
12-15-2011, 08:14 PM
To say a tennis ball does not compress when it hits the court is just stupid. Of course it will compress more when it hits the racket. But you can't sit there and say it doesn't compress when it hits the court. Hence the elliptical shape of ball marks and the much wider ball marks on like an overhead than a dropshot.
And the mark on a hardcourt is not as good of a representation of te actual bounce as it is on a clay court.

OddJack
12-15-2011, 08:21 PM
That part of the show doesn't bother me, its the fact the intended purpose is for the show primarily, not the integrity of the game when it is there to be utilized as such.
I think what woodrow was saying is the mark is inaccurate. He was talking actual ball mark not generated. He was saying the ball flattens out more than the mark shows (thats what I took from it), and I believe this to be false, thats why my statement pertains to his statement, though agreed not exactly to the thread. I do not think the HC ball mark to be perfect, but I believe it to be closer than HE +/- margin :)

We are splitting hair here, but thats ok.

See, there is a different between inaccurate and incomplete.

There is no doubt in my mind that the mark left on court is incomplete, meaning it's not a 100% representation of the the areas of the ball that actually touched the court. The outermost parts of the ball, which would be from a perfect circle to a long oval shape, do not touch the surface of the court as strongly as the center. That's why a real ball mark has a fade-away effect at its edges, unlike what we see on a hawk eye representation.

But we shouldnt be concerned with this difference. The mark left on court is good enough.