The Ref Stop

Jesus - VAR

The Inside Video Review feature produced by the MLS is a great tool and the PGMOL should absolutely be doing something like that. At least let us hear the refereeing discussions subsequently and their line of reasoning.

The PGMO's media communications really are very poor. They put up people who have little on-screen presence, provide unclear or dubious explanations, and provide little information. I've been impressed with Mike Mullarkey when I've heard him speak in hte past (e.g. the NEville and Carragher programme on Sky) and I think they should utilise him more. If necessary, they should take the lead more themselves and create their own platforms for broadcasting content, like the MLS have done with their website and Youtube channel. I remember there used to be a Premier League website where you could ask questions of referees and so on (Ref World?) but it was closed down pretty much immediately after Mike Riley took over which was a backward step really. The organisation needs to be modernised in terms of its communications.
 
The Ref Stop
I saw an interesting calculation (sadly not mine) today that suggests, given a frame rate of 50 frames per sec (on tv) and the speed at which a player runs, there is a margin of error of upto 20cm in any offside call, so any VAR decision giving offside in which a player is less than 20cm offside cannot be deemed to be “safe”

Perhaps one solution might be to go with the infield decision in such close cases?

I’ve attached a photo of the calculations, and you can see the original tweet here:

https://twitter.com/x/status/1163856424230936577

F5077DED-3810-4537-8BDE-06281F01FD79.jpeg
 
RefJef said:
I saw an interesting calculation (sadly not mine) today that suggests, given a frame rate of 50 frames per sec (on tv) and the speed at which a player runs, there is a margin of error of upto 20cm in any offside call, so any VAR decision giving offside in which a player is less than 20cm offside cannot be deemed to be “safe”

Perhaps one solution might be to go with the infield decision in such close cases?

I’ve attached a photo of the calculations, and you can see the original tweet here:

https://twitter.com/x/status/1163856424230936577

View attachment 3668
Click to expand...
Looking further down the twitter account, the same chap has predicted Newcastle will finish 10th, so he's obviously off his head and that discredits his VAR calculations! Let's say, 'he's not in a credible position to make a claim'
 
es1 said:
i think the outcome of this is fairly simple, the perpendicular lines that the VAR draws across the field should be 20cm wide and if there's any overlap of the defensive and attacking line then the result is no offside
Click to expand...
No. It would be "on-field decision" and the VAR does not change anything in such cases. A margin of error doesn't cut only in one direction.
 
Big Cat said:
Looking further down the twitter account, the same chap has predicted Newcastle will finish 10th, so he's obviously off his head and that discredits his VAR calculations! Let's say, 'he's not in a credible position to make a claim'
Click to expand...
I stopped in Corbridge this week and was talking to a staunch Geordie fan. They’re raging with Ashley over Rafa and the finances, Bruce hasn’t a chance!

They’ll need Mike Ashley to buy the PMGOL to survive I’d guess!
 
RefJef said:
I saw an interesting calculation (sadly not mine) today that suggests, given a frame rate of 50 frames per sec (on tv) and the speed at which a player runs, there is a margin of error of upto 20cm in any offside call, so any VAR decision giving offside in which a player is less than 20cm offside cannot be deemed to be “safe”

Perhaps one solution might be to go with the infield decision in such close cases?

I’ve attached a photo of the calculations, and you can see the original tweet here:

https://twitter.com/x/status/1163856424230936577

View attachment 3668
Click to expand...
I worked it out here, up to 46cm for 30 frames per second (more common frame rate) with much less calculations or complexity :)

And you can see the original post here :)
https://www.refchat.co.uk/threads/var-wobbly-lines.11773/post-116365
 
one said:
I worked it out here, up to 46cm for 30 frames per second (more common frame rate) with much less calculations or complexity :)

And you can see the original post here :)
https://www.refchat.co.uk/threads/var-wobbly-lines.11773/post-116365
Click to expand...

Thanks - and my apologies, I hadn’t seen that post of yours.

One little niggle I had with the version I posted was that the calculation didn’t factor in that the defender could be running the opposite way, which you calculation has done. I don’t have the technical knowledge to comment on frame rates.

Either way, the important point is is that there is potentially a margin of error of circa 20 to 50 cm, which is not insignificant.

Perhaps a “band of uncertainty” should be pasted onto screen, and any decision that falls into this zone should revert to onfield decision?
 
RefJef said:
Thanks - and my apologies, I hadn’t seen that post of yours.

One little niggle I had with the version I posted was that the calculation didn’t factor in that the defender could be running the opposite way, which you calculation has done. I don’t have the technical knowledge to comment on frame rates.

Either way, the important point is is that there is potentially a margin of error of circa 20 to 50 cm, which is not insignificant.

Perhaps a “band of uncertainty” should be pasted onto screen, and any decision that falls into this zone should revert to onfield decision?
Click to expand...
But that would defeat the purpose of VAR. At a level that VAR is used, you would expect AR's to get the ones that are not tight right pretty much every time. Its the tight ones we need VAR for and to revert that back to the AR...
 
Why is everyone treating what's essentially some random geezer on twitter as some oracle whose opinions on the laws of the game should be adhered to forthwith?
 
The frame rate of cameras used in the world cup were apparently 500 fps. That would supposedly bring the margin of error down to about an inch.

But here is a lot more to it than just frame rate. There is then the clarity of the image which is a combination of the camera's resolution and the sensitivity (iso) used to shoot. To explain this imagine the offside happens (foot) on the far side of the field to the camera. One pixel on the image could represent a distance of roughy anything from 1cm to 10 cm depending on the resolution. And the end of the foot could be anywhere in that pixel.

Even with very high speed and high resolution if low sensitivity/iso (light dependent) is used then the end of the foot will not look as sharp on one pixel but will be a blur set of pixels so deciding where the foot actually ends is not accurate.

I've said this before, technology-wise we are not ready for VAR. The right tech does exit but at this time the cost is prohibitive.
 
I'm perfectly happy with picking a frame and making a factual on/offside decision based on that still frame. You have to start somewhere and I'm not sure introducing error bars is a great idea for something that (even if you can't get a clear picture) will be a factual decision.

My issue comes in the selection of that frame. I've seen all the arguments around Sterling and I think it's perfectly reasonable to say that based on the picture produced, he's offside. I just think they've picked the wrong picture as the ball hasn't clearly left the passing player's foot. They should have cycled on another frame or two (or decide that offside happens when the kick is started and run it back a few frames) and then it would be a much clearer decision.
 
GraemeS said:
I'm perfectly happy with picking a frame and making a factual on/offside decision based on that still frame. You have to start somewhere and I'm not sure introducing error bars is a great idea for something that (even if you can't get a clear picture) will be a factual decision.

My issue comes in the selection of that frame. I've seen all the arguments around Sterling and I think it's perfectly reasonable to say that based on the picture produced, he's offside. I just think they've picked the wrong picture as the ball hasn't clearly left the passing player's foot. They should have cycled on another frame or two (or decide that offside happens when the kick is started and run it back a few frames) and then it would be a much clearer decision.
Click to expand...
The ball is kicked when a player makes contact with the foot
 
GraemeS said:
m perfectly happy with picking a frame and making a factual on/offside decision based on that still frame. You have to start somewhere and I'm not sure introducing error bars is a great idea for something that (even if you can't get a clear picture) will be a factual decision.
Click to expand...
There is the problem. You are not making a factual decision. You are making an educated guess on a factual event. With better technology what you call a factual decision can turn out to be not a fact at all.

GraemeS said:
My issue comes in the selection of that frame. I've seen all the arguments around Sterling and I think it's perfectly reasonable to say that based on the picture produced, he's offside. I just think they've picked the wrong picture as the ball hasn't clearly left the passing player's foot. They should have cycled on another frame or two (or decide that offside happens when the kick is started and run it back a few frames) and then it would be a much
Click to expand...
1566475464703.png
 
one said:
But that would defeat the purpose of VAR. At a level that VAR is used, you would expect AR's to get the ones that are not tight right pretty much every time. Its the tight ones we need VAR for and to revert that back to the AR...
Click to expand...

Not sure I necessarily agree, all technology has its flaws - LBW decisions in cricket stick with the onfield umpire's decision if the projected ball path is within half a ball's space, essentially accepting that there's a margin of error in which it would be improper to overturn an original decision.
 
Personally I'm happy to go with the VAR technology, even if it is not fully 100% accurate (which very little technology is.) It seems to me that it will give a higher level of accuracy than you could n average expect from a human being in real time and so is an improvement.
 
You must log in or register to reply here.
Back
Top