Shotspot and the line judges

Discussion in 'General Pro Player Discussion' started by lothar, Jun 2, 2004.

  1. lothar

    lothar New User

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    Seems like the French this year particularly sucked at looking at marks to tell if the ball was in or out. Is it shotspot that is off? Are they just really bad calls? Has it always been like this? Seemed pretty bad this year
     
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  2. Max G.

    Max G. Hall of Fame

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    Dunno. We don't know who was off and who wasn't.
     
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  3. Justyn Daniell

    Justyn Daniell New User

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    Tennis Magazine did an article on Shotspot a few months back and said that the mark that is shown is only off a few millimeters. So if a ball catches just the outside of the line, shotspot could show it out or vice versa.
     
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  4. predrag

    predrag Professional

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    Chair Umpire, at least does that for living.
    When he climbs out of the chair, goes down and looks at the mark, I will take that
    over the ShotSpot any time.
    What was happening at RG just proves what I was suspecting for some time now,
    Shotspot sucks. Big time.
    Interpolating is not the same as showing what actually happened.

    I remember couple of occasions during the Aus Open where Shotspot was so obviously wrong that was ridiculous.

    Regards, Predrag
     
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  5. dander

    dander Rookie

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    Has Interpol been brought in to solve this?
     
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  6. topspin

    topspin Semi-Pro

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    A question to the original poster: How can shotspot be blame for bad calls if the system is not used to make the calls???

    I think the reason you are seeing bad calls by the judges is because the courts get very dirty and it becomes extremely difficult to get up out of the chair and go check a line mark. I've played on clay and har-true and if the court is clean, it's fine, but once the court gets dirty, it's almost impossible. Even if you find the right mark, it's sometimes very difficult to judge if part of the ball hit the line.

    Shotspot would solve all of this since the system is very accurate (not perfect but accurate) and most importantly, is very consistent (unlike the human judges).

    If you want, check this link and read the msg by Max G:

    http://tt.tennis-warehouse.com/viewtopic.php?p=26068&highlight=shotspot#26068
     
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  7. topspin

    topspin Semi-Pro

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    btw I don't remember any incidents, not even one where shotspot was way off
     
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  8. Ballmachine

    Ballmachine Semi-Pro

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    This French Open has proved what I suspected all along. Shotspot is not perfect. Not by a long shot. I have been watching every match that stinking espn has broadcast, and in every match I have seen, there has been at least one discrepancy between the actual mark and shotspots results.

    Remember, Shotspot is a computer generated approximation of the ball. It is not absolute. Not by a long shot, and the marks on the court have proven it.

    I can't understand why the announcers seem to be convinced that shotspot is infallible. They are wrong.
     
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  9. rafael

    rafael Rookie

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    Or maybe the line judges are human. Most of the "bad calls" have been off by fractions of a centimeter. The dirt doesn't always leave a perfect mark.
     
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  10. Deuce

    Deuce Banned

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    What 'Ballmachine' said.

    It's ridiculous that the announcers go to the 'ShotSpot' animation as if it is the absolute, difinitive, conclusive judgement of the shot.

    Inkeeping with the subject, does anyone know how often they 'drag' the court at Roland Garros? Do they do it at the same time as the ball changes?
     
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  11. topspin

    topspin Semi-Pro

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    Ballmachine, you need to read that link I posted above. Just because something is a computer simulation, it does not necessarily mean it's not accurate. I think 99% is pretty good and I would take my chances with shotspot any day over line judges if I was a pro player.

    Also, the discrepancy between the actual mark and shotspots results could be easily explained since I don't believe they always get the right mark. Sure the judge gets up, goes down the steps of the chair and runs over to the mark (apparently without taking their eyes off the mark; how they do this without tripping and falling over is beyond me, they must be better athletes than the tennis players to achieve this), but once the court has been in use for a game or two, it becomes more and more likely that they will miss the real mark.

    I've never heard an announcer say that shotspot was infallible. If you have, I'd love to see a quote.
     
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  12. predrag

    predrag Professional

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    I lived in Toronto for 7 years.
    Definitely there are Har-Thru courts there. Other than my club, I've heard of quite a few.
    Don't they have clay courts in Montreal?

    If you are not able to point at the right mark on the clay court, you have no business
    being in professional tennis, as judge or player.

    I can point to the mark on the hard courts, most of the time, let alone clay.

    As someone said: You cannot be serious! A chalk flew up! :)

    Regards, Predrag
     
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  13. Verbal_Kint

    Verbal_Kint Rookie

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    Deuce, after every set.

    Marnix
     
    #13
  14. Ballmachine

    Ballmachine Semi-Pro

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    Who says that shotspot is 99% accurate? The company that makes it, that's who. That doesn't mean anything to me. Anybody can make any claim that they want, it doesn't mean that it is the truth. I have seen many instances when shotspot is wrong, but the announcers continue to back it as though it is correct every time.
     
    #14
  15. fastdunn

    fastdunn Legend

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    I do not know details of shot spot technology but I know I can
    calculate the location of objects if I have images from 3 cameras
    from different locations.

    There will be interpolation errors in time and space domain.
    In space domain, there are camera resolution limitation
    and computer algorithm inaccurcy in segmenting and registering
    same objects(ball and line) in 3 different images.

    Ballmachine is right when he says we need something like
    checking mark on clay in order to verify the accuracy of the shot
    spot. But I personally think one should use somekind of specialiezd
    surface to test ShotSpot performances.

    I would have ShotSpot override line calls if it dis-prove the given
    calls by larger than certain margin of error.
    Then again those margin of error might vary depending on
    locations.
    All of things I said assumes the ShotSpot uses the technique
    I described at the top of my posting.....

    FD
     
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  16. fastdunn

    fastdunn Legend

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    Oh by the way, in time domain, there's this limitations
    on shutter speed. You would have to interpolate to estimate
    the location of the ball in between image frames.

    I also wonder how they determine how much of the ball
    in the image actually touch the ground surface..

    We can always change the rule, I mean the "definition of
    in and out" in tennis, you know .....
     
    #16
  17. topspin

    topspin Semi-Pro

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    Shotspot was right on the money once again in the matches I've seen lately.
     
    #17
  18. topspin

    topspin Semi-Pro

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    I've played on har-true courts for a long time; played on them every day for a few summers. I've also played on the red indoor clay-like courts. So I know all too well how those marks look and how difficult it can be to judge if it touched the line at times (assuming the right mark was able to be found). One that is nice about these dirt types of courts is that it's hard for someone to cheat you on a call if you see the line come clean.

    I still say you have to be a heck of a super human to get down from a chair and not take your eye off a mark. The judges just have a general area in mind where they saw the shot land and they will focus on it and then climb down the chair and try to look for the "freshest" mark out there. Is this reliable? Only on a clean court. And most of the crucial calls happen at the end of a set when the court is at its worst and is in need of being cleaned.
     
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