For me VAR seems to have got it wrong from the beginning. Shouldn’t it be there for the ref to say they didn’t have a clear view of an incident and would like to see it again / want assistance on something? IE VAR to be initiated by the on field referee, not the other way round. Just seems they’ve gone from a very high bar on clear and obvious error where they didn’t overturn any decision to a ridiculously low bar where anything is getting overturned
VAR Farce
- Thread starter Ryanj91
- Start date
RefJef
RefChat Addict
@one s post is quite correct.
Essentially we have a 2D picture of a 3D situation. Any point in 3D can be identified as a set of co-ordinates (x,y,z)
(At this point, I’m going to deviate slightly from @one s excellent analysis: in my model, the touchline is the x axis, the goal line the y axis, and height the z axis.)
Any point on the 2D picture represents a line in the real 3D world. Thus, any point on the 2D picture (eg Firmino’s armpit) could have an infinite number of sets of co-ordinates, although in reality we know his armpit (z co-ordinate) will range from above zero to about 180cm. Below is picture that (hopefully) models this.
Similarly, Ming’s knee will have a range of values for the x (and y) co-ordinate depending on how high it is.
So, with only one 2D image it is impossible compare the co-ordinates of two different points, so this image alone is not enough to determine whether or not he was off-side.
However, with a second image, taken at the same moment but from a different angle it is theoretically simple to determine the exact 3D co-ordinates of any point on the image (the method is called triangulation) but in practice it is impossible to get an accurate measurement due to errors from lens distortion, light from a point spreading/dispersing and other technical factors. But it would be possible, with two (or more cameras) to come up with a set of co-ordinates with a given error range.
Perhaps VAR has used more than one image to come to their decision?
Two possible solutions:
Presentationly, numbers are less subjective than lines, so maybe then giving the x coordinate (or distance to goal line, or whatever), and error bounds, may make it a quicker and easier sell, and take out any human interpretation.
Anyway, I hope the above makes some sense - if not, do say, I suspect that, when I get time, I’ll turn this into a blog post.
Here’s a back of an envelope pic I drew that may help
Essentially we have a 2D picture of a 3D situation. Any point in 3D can be identified as a set of co-ordinates (x,y,z)
(At this point, I’m going to deviate slightly from @one s excellent analysis: in my model, the touchline is the x axis, the goal line the y axis, and height the z axis.)
Any point on the 2D picture represents a line in the real 3D world. Thus, any point on the 2D picture (eg Firmino’s armpit) could have an infinite number of sets of co-ordinates, although in reality we know his armpit (z co-ordinate) will range from above zero to about 180cm. Below is picture that (hopefully) models this.
Similarly, Ming’s knee will have a range of values for the x (and y) co-ordinate depending on how high it is.
So, with only one 2D image it is impossible compare the co-ordinates of two different points, so this image alone is not enough to determine whether or not he was off-side.
However, with a second image, taken at the same moment but from a different angle it is theoretically simple to determine the exact 3D co-ordinates of any point on the image (the method is called triangulation) but in practice it is impossible to get an accurate measurement due to errors from lens distortion, light from a point spreading/dispersing and other technical factors. But it would be possible, with two (or more cameras) to come up with a set of co-ordinates with a given error range.
Perhaps VAR has used more than one image to come to their decision?
Two possible solutions:
- VAR uses two (or more) cameras to calculate and compare the x-coordinates of the players, and also their error bounds. If the co-ordinates overlap within these error bounds, go with the onfield decision.
- Only use parts of the body that are in direct contact with the pitch (I.e.typically feet) to determine offside, as the z co-ordinate must be zero, therefor the x and y co-ordinates could be accurately determined.
Presentationly, numbers are less subjective than lines, so maybe then giving the x coordinate (or distance to goal line, or whatever), and error bounds, may make it a quicker and easier sell, and take out any human interpretation.
Anyway, I hope the above makes some sense - if not, do say, I suspect that, when I get time, I’ll turn this into a blog post.
Here’s a back of an envelope pic I drew that may help
Ah, its clear and obvious.... my bad!!!
Flies over my head, I'll stick to refereeing.
ladbroke8745
RefChat Addict
Moving away from EPL....
Was shown this video earlier.....
We know how the EPL operate. The referees trust those in the VAR room to give them honest opinions and they go with it.
But this one here shows a lengthy chat with the VAR room (in an international game U17 World Cup in Brazil) before heading to the screens and FAILING to still give the most blatant penalty in a long time. Thing is, he stopped the game following a corner to give a free kick TO Angola instead of the penalty to New Zealand. Yet there is absolutely nothing to suggest that a free kick should be given to Angola at all.
Whats your thoughts?
https://streamable.com/1adoe
Was shown this video earlier.....
We know how the EPL operate. The referees trust those in the VAR room to give them honest opinions and they go with it.
But this one here shows a lengthy chat with the VAR room (in an international game U17 World Cup in Brazil) before heading to the screens and FAILING to still give the most blatant penalty in a long time. Thing is, he stopped the game following a corner to give a free kick TO Angola instead of the penalty to New Zealand. Yet there is absolutely nothing to suggest that a free kick should be given to Angola at all.
Whats your thoughts?
https://streamable.com/1adoe
one
RefChat Addict
Makes sense to me @RefJef 
And IMO this case used neither of the two options you mentioned should be used. I think in general they possibly use the second option from what i have seen but in this case because neither player (attacker and defender) had the body part that was offside on the ground, the system left the alignment to the operator. If you saw the alignment of the lines live you would have see it was not the work of the system, there was a first alignment (first pic), possibly system suggested by the system, then a lot of movement to get the last one.
What I didn't even bring to equation was the line for the defender which IMO should have been further towards the goal line for similar reasons. The x axis is aligned to the tip of his left toe which is not only in the air but also further away from the near side line than the knee which means the drawn blue line should have gone further down and the yellow line further in. Anyway, I have always said the technology is not ready for this and this incident gives the further fuel to the public in not trusting VAR (factual).
And IMO this case used neither of the two options you mentioned should be used. I think in general they possibly use the second option from what i have seen but in this case because neither player (attacker and defender) had the body part that was offside on the ground, the system left the alignment to the operator. If you saw the alignment of the lines live you would have see it was not the work of the system, there was a first alignment (first pic), possibly system suggested by the system, then a lot of movement to get the last one.What I didn't even bring to equation was the line for the defender which IMO should have been further towards the goal line for similar reasons. The x axis is aligned to the tip of his left toe which is not only in the air but also further away from the near side line than the knee which means the drawn blue line should have gone further down and the yellow line further in. Anyway, I have always said the technology is not ready for this and this incident gives the further fuel to the public in not trusting VAR (factual).
one
RefChat Addict
Tough one there. I can see why he made that decision. I think its the fair decision although strictly speaking it is incorrect. Make this a penalty and you'd have attackers around the keeper all the time stopping them from free movement.
Law defines impede as "To delay, block or prevent an opponent’s action or movement". In this case the NZ player did it before the ball was in play. The keeper should have left it to the referee or at least pushed the attacker before the ball in play too. Poor defending though, a defender should have been there protecting the keeper.
They do use multiple cameras for this 3D stuff, including those used by GLT (which have a far higher frame rate... quote S.Attwell)@one s post is quite correct.
Essentially we have a 2D picture of a 3D situation. Any point in 3D can be identified as a set of co-ordinates (x,y,z)
(At this point, I’m going to deviate slightly from @one s excellent analysis: in my model, the touchline is the x axis, the goal line the y axis, and height the z axis.)
Any point on the 2D picture represents a line in the real 3D world. Thus, any point on the 2D picture (eg Firmino’s armpit) could have an infinite number of sets of co-ordinates, although in reality we know his armpit (z co-ordinate) will range from above zero to about 180cm. Below is picture that (hopefully) models this.
Similarly, Ming’s knee will have a range of values for the x (and y) co-ordinate depending on how high it is.
So, with only one 2D image it is impossible compare the co-ordinates of two different points, so this image alone is not enough to determine whether or not he was off-side.
However, with a second image, taken at the same moment but from a different angle it is theoretically simple to determine the exact 3D co-ordinates of any point on the image (the method is called triangulation) but in practice it is impossible to get an accurate measurement due to errors from lens distortion, light from a point spreading/dispersing and other technical factors. But it would be possible, with two (or more cameras) to come up with a set of co-ordinates with a given error range.
Perhaps VAR has used more than one image to come to their decision?
Two possible solutions:
- VAR uses two (or more) cameras to calculate and compare the x-coordinates of the players, and also their error bounds. If the co-ordinates overlap within these error bounds, go with the onfield decision.
- Only use parts of the body that are in direct contact with the pitch (I.e.typically feet) to determine offside, as the z co-ordinate must be zero, therefor the x and y co-ordinates could be accurately determined.
Presentationly, numbers are less subjective than lines, so maybe then giving the x coordinate (or distance to goal line, or whatever), and error bounds, may make it a quicker and easier sell, and take out any human interpretation.
Anyway, I hope the above makes some sense - if not, do say, I suspect that, when I get time, I’ll turn this into a blog post.
Here’s a back of an envelope pic I drew that may help
BTW, I thought 'firmino's armpit' was a mathematical term for a moment haha
If I had a £ for every VAR fix I've heard... well, I'd have a lot of £'s (and no fix!)
They all miss the point... It's broken beyond repair
My crystal ball has technology quickly alerting puppet ARs to offside and ball in/out within maybe 2-3 years, but the subjective stuff is dead
Alas, only commercial forces will drive change reversal & I'm pessimistic about this because the younger generation want science, not sport (at any cost)
They all miss the point... It's broken beyond repair
My crystal ball has technology quickly alerting puppet ARs to offside and ball in/out within maybe 2-3 years, but the subjective stuff is dead
Alas, only commercial forces will drive change reversal & I'm pessimistic about this because the younger generation want science, not sport (at any cost)
I really like how the French players deal with VAR...
socal lurker
RefChat Addict
We've beat the dead horse quite a bit, but what they hey . . .
One of, if not the, biggest problems for soccer is that unlike most sports video review is being used for subjective decisions. That's because most of the purely objective decisions aren't that important--and GLT deals with the most significant one. There is the objectivity of OSP at the moment of judgment, but that lacks the static element that most sport reviews have (a line that is solid or whether something touched the ground, a single question of who touched the ball last). Looking at a video can never make a subjective decision objective. All it can do is give more angles from which to base the subjectivity. On some plays, that makes it easy to see a decision was incorrect and fix it. But more often than not, it leaves people arguing.
And the PL seems to have excelled at taking a flawed system and making it worse . . .
One of, if not the, biggest problems for soccer is that unlike most sports video review is being used for subjective decisions. That's because most of the purely objective decisions aren't that important--and GLT deals with the most significant one. There is the objectivity of OSP at the moment of judgment, but that lacks the static element that most sport reviews have (a line that is solid or whether something touched the ground, a single question of who touched the ball last). Looking at a video can never make a subjective decision objective. All it can do is give more angles from which to base the subjectivity. On some plays, that makes it easy to see a decision was incorrect and fix it. But more often than not, it leaves people arguing.
And the PL seems to have excelled at taking a flawed system and making it worse . . .
one
RefChat Addict
That's the whole point. If you can't use 'the lines' for this accurately, what makes you think you can use it for offside accurately. Technology used is not fit for purpose. The margin of error it too much to be acceptable give some offsides are decide on millimetres.
