High time ICC have a check on the umpires

[marc71178]

No. It follows the ball until it hits the batsman's pad not until it pitches. So, it has all the information about the ball's behaviour before it hits the pad and predicts based on that.

That still doesn't mean that anything other than where the ball pitches is 100% accurate.

 

[shankar]

Gravity, air resistance and so on is factored in - note how a ball decelerates through the air upon leaving a bowler's hand, but that is always a 'guesstimate'. I wonder whether the software actually takes into account widn speed and direction, barometric pressure, relative humidity, temperature and the like. All these will affect the trajectory.

The biggest problem Hawkeye has is that is attempting to predict the future path of the ball.

I know it's not possible to predict the path ball anywhere close to 100%. I've already mentioned it. All I'm trying to prove that Hawk-eye is more accurate than the umpire's estimate.

As marc stated, you cannot tell what will happen based upon what has happened. You can only approximate. Why do you think a ball swings? Ah, the age-old question. Well, the answer is simple - aerodynamics. The aerodynamics of a near-spherical object should be simple to work out, but of course they are not. The reason for that is the ball is far from spherical - it has a seam and two quarter-seams. Bowlers shine one side of the ball, keep one rough, sometimes load one side of the ball with moisture, sometimes not. Shiny side in, shiny side out. Seam pointing to the slips, seam upright, seam scrambled, seam to fine leg. Left arm, right arm, side-on, chest-on. Slow, medium, fast. All will affect the trajectory of the ball in one way or another - and coupled with the aforementioned atmospheric conditions, it gets more and more complicated. Do you think that the programmers of Hawkeye could factor all those things in?

I know the process that goes into making the ball swing. (My final-year project is on CFD simulation of vortex wake behind a sphere which I hope to finally apply to a ball swinging :original: ). But the point is the makers of Hawk-eye don't need to know that. They just need to know what the ball's path until it meets the pad and they predict based on that which is what an umpire does. The umpire thinks:"okay the ball has started outside off reached middle, it has bounced this much,it has moved off the pitch this much so based on that its likely that it'll reach here". This process can be better done by a computer and a set of cameras.

How many times do you see the wicket-keeper made to look a fool by late swing?

Yes.Hawk-eye can't predict this.But neither can an umpire and the lbw rules dont require the decision to take into account such unpredictable movement

 

[marc71178]

I know it's not possible to predict the path ball anywhere close to 100%. I've already mentioned it. All I'm trying to prove that Hawk-eye is more accurate than the umpire's estimate.

But that's the problem - Hawkeye is inflexible and cannot take into account the conditions such as what previous deliveries have been doing - it isn't actually on the field following the game.

 

[luckyeddie]

At the end of the day, Hawkeye is a guide. It's also a machine - as such it is subject to its own problems or limitations.

If the final say over lbw's was down to technology, what would happen if there was a power failure? "Sorry. Play suspended for the day owing to the fact that no-one's got a fifty pence piece for the electricity meter".

I'm totally in favour of technology being used to determine no-balls, though - the same idea has prevailed at tennis matches for 20 years or more.

 

[shankar]

But that's the problem - Hawkeye is inflexible and cannot take into account the conditions such as what previous deliveries have been doing - it isn't actually on the field following the game.

Why does it need to?

 

[marc71178]

Because quite simply, if it doesn't than it is not taking into account the current conditions going on - the umpire being out in the middle quite clearly can and does.

 

[shankar]

Because quite simply, if it doesn't than it is not taking into account the current conditions going on - the umpire being out in the middle quite clearly can and does.

But the hawk-eye does take into account current conditions indirectly because whatever is happening to the ball over 20 yards is due to the "conditions". The umpire does the same thing hawk-eye does of extrapolating the ball's path. Are you saying that even if the ball hasn't swung till it hits the batsman, the umpire, due to his knowledge of the conditions,can predict that it would have swung if it had passed the batter which hawkeye can't do?

 

[marc71178]

Yes, the umpire can do that, because he's been there WATCHING the action of the ball over the rest of the game.

Hawkeye has not, and will not in its present guise be any more accurate in predicting the path of the ball than the umpire.

 

[Newlands]

It's true that it's not 100% accurate. What that means is if hawkeye says the ball grazes the leg-stump or clips the top of a stump then you cant trust it. But if it says that the ball is crashing into middle of a stump then you can confidently say that the batsman was out.

Yes and generally umpires are accurate enough to know that something is plumb. He (or she :original: ) can be pretty confident about that. You don't need technology to let you know if something is going to send the stumps into next week or not. I would have hoped that if hawkeye was brought into the game that it would be used to find out whether the ball would have skimmed or clipped. Like the third umpire is used in close run outs. They don't signal for the 3rd umpire if the batsman is five feet away from the crease. He's gone!

 

[shankar]

Yes, the umpire can do that, because he's been there WATCHING the action of the ball over the rest of the game.

Hawkeye has not, and will not in its present guise be any more accurate in predicting the path of the ball than the umpire.

An umpire can't let his knowledge of previous balls influence his decision...If the ball has been swinging a lot but the ball in question has not swung at all when it hits the pad are you saying that the umpire due to his "knowledge of the conditions" will base his decision on his experience that the ball would have swung had it passed the batsman which hawkeye cant do?...because that would be a wrong decision.

 

[Swervy]

An umpire can't let his knowledge of previous balls influence his decision...If the ball has been swinging a lot but the ball in question has not swung at all when it hits the pad are you saying that the umpire due to his "knowledge of the conditions" will base his decision on his experience that the ball would have swung had it passed the batsman which hawkeye cant do?...because that would be a wrong decision.

but that is only an umpire using his experience...these guys are there to make JUDGEMENTS using their experience of the game

 

[luckyeddie]

An umpire can't let his knowledge of previous balls influence his decision...If the ball has been swinging a lot but the ball in question has not swung at all when it hits the pad are you saying that the umpire due to his "knowledge of the conditions" will base his decision on his experience that the ball would have swung had it passed the batsman which hawkeye cant do?...because that would be a wrong decision.

er, sorry......

You have missed the one thing which must always be taken into account - BOUNCE. Umpires have to take previous deliveries into account - why do you think that the majority of iffy decisions for lbw are in the first innings of a game? Because the umpires are not used to the bounce of the wicket.

Swing is the easiest thing to account for, because it happens relatively slowly (over a few yards of motion - at the precise point where the ball STARTS to swing it is still travelling in a straight line. Over thew next few yards it turns more and more.

Spin happens INSTANTLY, as does bounce - the ball physically changes direction and then continues in a straight line in the 'new' direction (ok, a parabola affected by gravity).

 

[shankar]

You have missed the one thing which must always be taken into account - BOUNCE. Umpires have to take previous deliveries into account - why do you think that the majority of iffy decisions for lbw are in the first innings of a game? Because the umpires are not used to the bounce of the wicket.

Yes it is important and hawk-eye does take that into account because it uses the path that the ball takes after it lands on the pitch till it reaches the batsman for gauging the bounce. So it doesnt need any knowledge about the wicket because what is important is would the ball in question have hit the wickets had it behaved in accordance with its path prior to hitting the pad (which as you pointed out is not always true but the laws dont require the decision to take into account every unpredictable quirk of the ball)

Also note that I'm not saying technology should replace umpires or anything like that. I was just refuting marc's opinion that the hawk-eye is not more accurate than an umpire.

 

[Lions81]

er, sorry......

You have missed the one thing which must always be taken into account - BOUNCE. Umpires have to take previous deliveries into account - why do you think that the majority of iffy decisions for lbw are in the first innings of a game? Because the umpires are not used to the bounce of the wicket.

Swing is the easiest thing to account for, because it happens relatively slowly (over a few yards of motion - at the precise point where the ball STARTS to swing it is still travelling in a straight line. Over thew next few yards it turns more and more.

Spin happens INSTANTLY, as does bounce - the ball physically changes direction and then continues in a straight line in the 'new' direction (ok, a parabola affected by gravity).

Computers can launch missiles thousands of miles with pinpoint accuracy. Computers can fly planes (and surely land them too, if not for the pilot's union), and yet computer's can figure out how much bounce a ball is going to get. Maybe on the first ball delivered, when the computer has no previous balls bouncing to base a decision on. But then neither does a human umpire. I think the real problem is an inherent distrust of technology. Just because a computer can do a better job determining LBW decisions than a human being doesn't make humans inferior, and so Marc and LE, you don't have to be scared of computers. Embrace them!

 

[marc71178]

Maybe on the first ball delivered, when the computer has no previous balls bouncing to base a decision on.

The computer doesn't base anything on the previous deliveries in Hawkeye's case - it takes each ball in isolation.

Just because a computer can do a better job determining LBW decisions than a human being doesn't make humans inferior, and so Marc and LE, you don't have to be scared of computers.

And can you conlusively prove the computer is better? I don't think so seeing as there are too many unknowns.

 

[ReallyCrazy]

marc ofcourse the computer is better. It processes information much faster and much more efficiently than a human can. That is a fact. It doesn't matter if each ball is taken into account in isolation..in fact that is the way to go as each ball is different. The previous ball should have no bearing on the decision.

But all things said, I still don't want umpires to be replaced. There always should exist a human element to the game. That is what makes it more interesting and gives a personal touch. I just want competent umpires who are not worked too much. Right now, there are only 8 umpires on the panel. With cricket being played all round the year, the umps are making more tours than players and its too much. For example I have seen bucknor all over the place of late.

Finally if an umpire is showing too many signs of decline as Bucknor has, he should be replaced.

PS: good luck eyes_only

 

[shankar]

The computer doesn't base anything on the previous deliveries in Hawkeye's case - it takes each ball in isolation.

I have said this again and again....It does not need to take into account previous delieries. What's required to predict a ball's destination is how much that particular ball swung,bounced and seamed.

I think I understand the nature of your problem now. Umpires need to know the nature of the wicket,the behaviour of previous deliveries because he cannot exactly gauge how much the ball in question has bounced. For e.g. when the ball hits the batsman's pad immediately (in a short distance) after pitching, the umpire doesnt know how much it would have bounced. Here he uses his knowledge of the bounce of the wicket to make a decision. But since hawk-eye has this on camera it knows the angle at which the ball rose and hence how much that ball would have bounced. So, umpires need to know the match conditions, experience abt. the wicket etc... Hawk-eye doesnt need to know these.

I reiterate that I dont want umpires to be replaced by technology.

 

[rolande]

humans are and will be less accurate than computers however a computer cant have anythng to base its desicion on without humans. also i reckon a 12 year old's knowledge would prolly blow up a state of the mainframe supercomputer

 

[marc71178]

The previous ball should have no bearing on the decision.

Why not?

If a ball is seaming around all over the place, that should effect the decision.

Hawkeye cannot accurately capture that.

 

[marc71178]

I have said this again and again....It does not need to take into account previous delieries. What's required to predict a ball's destination is how much that particular ball swung,bounced and seamed.

And the best way of working that out is observing recent behaviour of the ball.

For e.g. when the ball hits the batsman's pad immediately (in a short distance) after pitching, the umpire doesnt know how much it would have bounced. Here he uses his knowledge of the bounce of the wicket to make a decision. But since hawk-eye has this on camera it knows the angle at which the ball rose and hence how much that ball would have bounced.

That sort of situation is where Hawkeye is at its worst.

Because of many factors such as how the ball has been scuffed, which side is facing which way and how the ball can move not immediately after bouncing - Hawkeye cannot be anywhere near 100% what the ball will do if it strikes the pad immediately after pitching.

Since it is therefore not near 100% there is no justification for employing something which is not guaranteed to make any more accurate a decision and will only slow the game up at a time when over rates are bad enough as it is.