IN or OUT?

Discussion in 'Rules / Tournament Regulation / Officiating' started by mark_palmos, Feb 17, 2018.

  1. mark_palmos

    mark_palmos Regular Member

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    EDIT: answer to this long thread is this:
    I got an email from a gentleman who works for Badminton World Federation, and he said it is definitely based on physical touch, not overlap... so in my photos in the post below, the bird is OUT! This kinda makes it easy to determine from a nearby ON court position (easier perhaps than for a line judge), because if you are on the court and near the shuttlecock you can see if there is any "daylight" between the white line and the white cork. If so, it is out. If not, it is in.
    ____________________________________________________________

    ORIGINAL POST:
    Hello all. I wonder if you could help me clarify the rule about what part of the shuttlecock determines whether a line call is on or out...

    In my badminton club we have been debating whether IN and OUT calls are made similarly to tennis and football, where the ball/shuttlecock is viewed from above, and if any part of the shuttle cork is OVER the line, it is IN.

    But some in our club say that because the bottom bit of the cork, which is the part that touches the ground, is several millimetres back from the edge of the cork, it is NOT determined like tennis or football, but the middle of the bottom of the cork, which is the only part that TOUCHES. Of course you cannot see this part of the cork anyway, So which is it? I would love to know, and if possible, to get a rule book quote. I have been searching for the answer for days, and have not found it.

    Thank you,

    Mark Palmos.




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    #1 mark_palmos, Feb 17, 2018
    Last edited: Feb 22, 2018
  2. sautom88

    sautom88 Regular Member

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    It doesn't matter anyway because our human eye can't even see the contact point on the court's surface. The contact point is probably abt 4-5mm in diameter, and we're looking @ it from at least 2-3m away from it. Esp @ clubs, where some players often cheat..:p:p:p :D:D:D
     
  3. mark_palmos

    mark_palmos Regular Member

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    Hi, I think it does matter, quite a lot. Firstly, 4mm is a lot of "fudge room" ... It should be exactly determinable. If you see the two photos, the one bird looks in, the other out, all because the one viewed from the side you can see under the widest part of the cork... So if this rule was made clear, players would be able to make allowances for the view from above vs from the side... But as far as I know there is no rule which says which part of the cork is the bit that you judge by! There really should be.

    Mark. [​IMG][​IMG]

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  4. llrr

    llrr Regular Member

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    I think hawkeye uses the full diameter of the cork to determine if the shuttle is in or out, rather than the single "point" or much smaller circular area that's touching the surface, which is why it's always a perfect circle with the diameter equal to the cork. From this, I have to deduce that in/out is based upon the widest diameter of the cork. Your example above would therefore be considered in.
     
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  5. OhSearsTower

    OhSearsTower Regular Member

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    The perfect circle is reasoned in the simple graphic animation, right?

    From my understanding at a sportsman i always thought the contact point of the cork is deciding. I have never investigated about it though because (at least i thought so) it was the only logical way for me. So I clearly disagree with mark_palmos "in" shuttle.

    It can happen that the cork landed out but the feathers touch the line. That is out for me as well.
     
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  6. sautom88

    sautom88 Regular Member

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    I agree w/ OhSears, its the contact point that matters. Both pics above r 'out'. If its judged by the diameter of the cork, it'll be really difficult to judge whether it's in or out.
    But, who can really see in the split millisecond on the impact? Superman maybe? :D:D:D. Also, how abt the possibility of playing against cheaters in the club?
    How do we solve that? :(:(:(
     
  7. LD rules!

    LD rules! Regular Member

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    If you are only playing with plastic shuttles then it cannot be too serious anyway. Like others have said, it is so split second that you should probably just play a let and move on each time if it is causing such bother.
     
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  8. llrr

    llrr Regular Member

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    I would've assumed that only the contract point should be considered but then why is the Hawkeye shadow so big? The contact area is tiny.
     
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  9. mark_palmos

    mark_palmos Regular Member

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    Amazing that nobody actually knows the answer! BTW the fact we use plastic is besides the point. Are there one set of rules for feathers and another for plastic that doesn't matter? What a snobbish attitude.

    I'm really curious as to which it is. To me the "ball" of the cork makes sense seeing its impossible to see contact point unless you have your face on the court. Tennis and football use this method, im guessing, because it's a lot easier to determine accurately.

    But I'm interested in the facts, not theories... Anyone know?

    Thanks,
    Mark.

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  10. stanleyfm

    stanleyfm Regular Member

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    I believe from my experience playing badminton since childhood, watching it on TV and live also since childhood, it should be the contact point.

    But anyway, usually @phihag will know the answer
    Any opinion Phil?
     
  11. stanleyfm

    stanleyfm Regular Member

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    the contact area is not that tiny
    anyway, if you think about it, there is the hawkeye which result in a shape that is not a circle shape, but instead is ellipse when it travels in fast speed with angle
    this support the idea that it is the contact point that matters instead of the 'perfect circle' of the cork
     
    #11 stanleyfm, Feb 18, 2018
    Last edited: Feb 18, 2018
  12. llrr

    llrr Regular Member

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    The contact area of any circular or spherical object with a flat surface is literally a single point. The visible circle then must be due to compression of the cork similar to that of a tennis ball when it hits the surface. Since some amount of the cork will always compress as the shuttle lands from a practical perspective it would be close if not the full diameter of the cork is considered as in or out. Only in a theoretical perspective where you place the shuttle on the ground can you say that only the contact point matters, but of course I was referring to a practical perspective only.
     
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  13. phihag

    phihag Regular Member

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    Formally, the IRS informs the umpire just about In/Out/No Decision. HawkEye's animation graphic is meant for the public layperson and has no relation with the actual laws. That's why when the animation is seriously wrong it's no big deal.

    The rules are simple:

    There is no mention of a particular perspective, or some part of the shuttlecock.

    As such, the only interpretation I see is that when the shuttle first hits the ground, that area where it hit counts.

    I venture that this area is extremely small, around the size of an atom (if I'm wrong: @speCulatius please correct me on that).

    Very sensibly, this means we can regard the contact area as a point (at least for human scales ≫1nm), not an area, and therefore don't have to discuss about any intersection; if that point is on the line it's in, if it's not it's out.
     
  14. llrr

    llrr Regular Member

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    But if a small area from the Hawkeye shadow touches the line the shuttle is considered in, which contradicts this.
     
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  15. visor

    visor Regular Member

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    Lol... the contact point is not 1 atom width. There's compression of the cork head and also compression of the mat surface on contact... the animation graphics do look appropriately right sized, and they only look big when the graphics go into zoom mode.
     
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  16. llrr

    llrr Regular Member

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    This was my point and hence I say that in a practical sense, a circle close to the width of the cork is used to determine if the shuttle is in or out. Only in a theoretical sense, where the cork is ideally perfectly spherical, and is placed on the floor, then the contact point would be a single point. Hence, if the above situation occurred as in the photos Hawkeye would've called it in.

    Btw I'm not saying in any way that hawkeye is infallible, only that since it is used to determine whether the shuttle is in or not, we can infer then what constitutes as in or out.
     
    #16 llrr, Feb 18, 2018
    Last edited: Feb 18, 2018
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  17. phihag

    phihag Regular Member

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    How so? Again, the HawkEye animation is for the public, and completely unrelated to the actual law.

    Forgive me, but my understanding of physics is that, barring air pressure (which I'd thought we could ignore here), compression only occurs after contact of two objects (shuttle and floor). Do you disagree?

    Assume there is a time when the shuttle is just above the mat, and a time somewhat later when shuttle and mat are in contact (or, to use the official wording, the shuttle hits the floor). If we bisect, i.e. go to the time in the middle between both timestamps, we can still evaluate whether shuttle and mat are in contact. If they are, we can evaluate an earlier time, if they are not, a later time. We can do this bisection until we arrive at physical limits, can't we?
    And at that timescale, everything is so incredibly slow that I would very much surprised if any two actions happen during one tick.
    Of course, I am assuming that we can precisely evaluate whether two physical objects are in contact, by listing each to a set of atoms, and precisely determine whether any two atoms are in contact.

    So where do you see the fault in my reasoning, apart from Lol?
     
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  18. llrr

    llrr Regular Member

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    Example:



    Pause at 0:51 and you can see that the contact point is outside the line, but the shadow is used and hawkeye called that in.

    I have to say that I feel like hawkeye isn't as good in badminton as tennis from what I've seen. One thing really irks me: Hawkeye always show shuttles as circular. A fast smash will cause the shuttle to skid a bit before bouncing up, why is it not oval shaped? The skid is clearly visible on a fast tennis shot but not for shuttles. This brings me to think that for badminton, in fact it is pre-determined, as in, hawkeye uses a fixed circle irrespective of the type of shot played.

    Edit: For people too lazy to try to pause at 0:51 :p

    Capture.PNG
     
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  19. visor

    visor Regular Member

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    ^ We have to keep in mind that Hawkeye is not 100% accurate... there's a +/- error tolerance involved, just as in any measurement system. I seem to recall in tennis it's +/- 2mm or so.

    In some of those unusual Hawkeye results in badminton, I'm sure it's due to those error tolerances, plus there's also the unusual flight dynamics of the shuttle (that can be affected by draft, shuttle wear, etc) which is much more complex than a simple projectile like a tennis ball.
     
  20. llrr

    llrr Regular Member

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    But this is irrelevant to the accuracy of hawkeye. I'm not saying that in the above situation, hawkeye predicted the flight and landing of the shuttle perfectly. All I'm saying is based upon what was shown, hawkeye determined the shuttle to be "in" with respect to where the shuttle is, despite the contact point being outside the line. However, we can clearly see that a part of the cork is indeed in, and this coincides with the circular shadow shown and the final call. From this, we have to infer that whether a shuttle is in or not must be based upon a circle of some diameter (presumably equal to the cork), and not simply the tiny point of contact.
     
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