Resolving the Parallax Error

Submitted by santy on November 28th, 2016 at 7:09 AM

EDIT: TLDR - From what I can estimate the tip of the ball crossed the plane of the first down (as I define it) by about two inches. The margin of error indicates there is a possibility it might not have, but that's unlikely :(


THE SPOT has been debated to death. Both OSU and us have provided camera angles that "prove the result", without really doing so because of the following resons: When a still camera image is analyzed, it begs the question "was that taken at the instant of forward progress by Barrett?". When a moving image is analyzed, the issue of parallax error is not resolved fully enough, even for #ThePerfectAngle. It is pretty important to do so simply because it is such a close call.

The most important variable to resolve is Time. Now both wolverines and buckeyes have all seen this GIF and drawn various conclusions and posted screenshots that vindicate their arguements and show their gross negligence of parallax error. 


Let's a closer look at this. I've taken the liberty of running through the GIF frame by frame and have isolated the instant where Barrett has made the most forward progress. This would be Frame 53 shown below:

Okay, so now we've got Time out of the way. This image has been posted by many buckeye fans because they can just draw a line along the 15-yard line and say that the tip of the ball is clearly past that line demonstrating that education system in ohio has yet to incorporate the concept of a parallax error in the school syllabus. 

The most important step in this is to determine exactly where along the width of the field the ball is at this instant. If we can do that, we can resolve the parallax. Fortunately we have a few clues. Here is Barron's picture from Ace's game recap:

It's a really useful shot because of when it was taken. The positioning of Jourdan Lewis' feet correspond to Frame 51/52 of the GIF above, which places this at almost the instant of most forward progress. The first thing this shot tells us is that the front tip of the ball is lined up vertically over Barrett's left pinky finger from this angle. [EDIT: I mean to say that the ball, Barrett's hand, and Barron's camera are all on the same vertical plane. The blue lines below are parallel to the intersection between this vertical plane and the field.] 

The relative positioning of the hash marks in the bottom right corner actually give us a pretty good estimate of this angle shown by the light blue line. It also tels us that the ball is slightly past Wormley's right arm.

If we assume that Barron was sufficiently far away, we can slide that blue line down to the outside of Barrett's left hand we know where along the 15 yard line the ball would have had to be in order to cross the first down.

Here is where things start to get a little tricky. Where exactly is the plane for the first down located relative to the 15-yard line? If we assume that it is at the border of the 15-yard line facing midfield and assume that the TV camera that recorded the GIF is not rolled to either left or right, we can resolve the prallex error. First we draw the position of the presumed boundary for the first down (shown in pink):

The intersection of the pink and blue lines indicate the position of the ball projected down onto the field, if it had crossed the plane for a first down. Again, if there were no roll variations in the camera that recorded the GIF, we can simply draw a vertical line (in light green) from this intersection to mark the boundary of the first down with the parallax error resolved:

I've drew the green line with a gap around the area where the ball should be. I've run through the GIF frame by frame several times, and there is a light spot only a couple of pixles big to the left of Wormley's forearm and I believe that is the white stripe of the football. You'll notice on Barron's picture that the stripe is facing up so it makes sense that it should be barely visible from this angle. You can also see that it is literally a pixel past our hypothesized first down line. Given the dimensions of a typical football, that would make the tip 2-3 pixels past the green line. 


It really depends on where exactly you define the plane of the first down to be. Is it the edge of the 15-yard line as I drew it? Is it on the opposite edge? Is it right down the middle? FWIW, the width of the line is 9-10 pixels on the GIF.


P.S. With regards to the tweet below,




The frame in this video that corresponds to Frame 53 in the GIF above (I used the positioning of Gedeon's legs to figure this out) has OSU's #73 obstructing the view so it's not very conclusive, also the ball was under Wormley's arm and part of it was past his arm as clearly seen in Barron's photo.



November 28th, 2016 at 5:51 PM ^

Note the position of the camera relative to the line. This angle will naturally make it appear the ball is farther behind the line than it is. If this were exactly parallel with the line, it would be conclusive, but as it stands, it's not.

This is why it's infuriating that so many times the endzone cameras are not exactly on the goal line.


November 29th, 2016 at 7:48 AM ^

We can tell from the photos that his left hand is extended out towards the 1st Down line and the ball is behind it in his right hand.  So, in the video footage attached to these two tweets, if you look at where his left hand was {as a point of reference}, at his furthest point of forward progress, it is easy to see that his right hand/the ball were well behind where his left hand was extended to, and from that point on his left arm came up and out and his right arm/the ball fell back:

Most of all, HOW DO THEY NOT EVEN BRING OUT THE CHAINS to measure the spot in a game of that magnitude???  RIDICULOUS!!!


November 28th, 2016 at 7:28 AM ^

I just can't anymore. This is like going back over my horrendous Stats 402 midterm for the third time trying to understand what the hell went wrong. Let me die, please.

Mabel Pines

November 28th, 2016 at 7:29 AM ^

Ain't nobody got time for this during the game.  Naked eye test is the best.  Dude didn't make it.  Game over.  Much rejoicing.  muppets.  We were robbed of Muppets.


November 29th, 2016 at 12:55 AM ^

Your team gained 180 inches of offense in the 4th quarter. But you are upset over an inch or two on one official's spot. The Buckeyes ran 540 inches untouched on one play after The SPOT for the win. The game was not won on The SPOT - you had the Buckeyes 15 yards from a win. You failed to stop them. We had three times your team's 4th quarter offense on that final play.

You have to play 4 quarters. The younger and better team played 4 quarters. They won. Case Closed.

Thanks to Michigan fans that expressed compassion for what happened in Columbus today, you deserve tons of respect for that and respect for the battle you gave the Buckeyes last Saturday.


November 30th, 2016 at 6:53 PM ^

So according to your "reasoning," the non-calls on the defensive holding and PI that OSU committed had nothing to do with how few yards/inches UM gained in the 4th quarter?  And the non-calls on OSU's offensive holding had nothing to do with how many yards/inches OSU gained in the 4th quarter?  Seriously??

Blue and Joe

November 28th, 2016 at 11:46 AM ^

It does matter. As OP says, we don't know where exactly on the line the first down marker is. It could be on the front, back, or middle. The ball could have been literally one chain link short or 1 inch past it. That is why you bring out the chains. Looking at this through camera angles when they had a physical representation on the field is dumb.

Goggles Paisano

November 28th, 2016 at 1:04 PM ^

It is at the beginning of the line.  The tip of the ball to start OT is placed at the beginning of the 25.  Thus the mark to gain is the beginning of the 15.  Just like a TD is getting the ball to the beginning of the goal line.  

The ref knew he had to spot it at the 15 for the first down and that is what he did.  No need for chains if you mark it at the 15.  I'm not thrilled with the spot but I have no complaint whatsoever that the chains were not brought out.  


November 28th, 2016 at 8:43 AM ^

The spot was well onto the line. I'm not sure how they got that. The miliseconds that they would have saw the forward progress seems unlikely. I also keep looking at where number 88's ass is when Barret bounces off, and it is behind the line, and the ball is barely on top of him, I just don't see it. Live it did not look like he made it. 

I know this has been brought up here, but number 88 had arms outside of Wormley, wrapping him up in a tackle.  That is not a pancake and should have been a holding penalty. It should have been 4th and 10  with a 42 yard field goal to push for a 3rd OT. Wormley did an amazing job, seemingly stopping JT while being tackled himself. 


November 28th, 2016 at 7:39 AM ^

Referees should be instructed/taught to rule a player short unless he absolutely and definitively gets the yardage needed on fourth down plays. You simply cannot give a player the benefit of the doubt and then throw out the indefinitive card.


November 28th, 2016 at 7:41 AM ^

going to be honest, after rewatching the game, I think he got it, in a very "tie goes to the runner" way. Ball met arm at exactly the 15, I can't fault the official for marking it where he did. What I can blame the officials for are the fourteen holds that OSU got away with on the play before to set up short yardage, as though they had decided that holding was simply not a rule anymore. In truth, the spot was 50/50. Focusing on that to the exclusion of the multiple other egregious errors actually detracts from the real issue. Penalties simply did not apply to OSU in this game and that was really unfair to our players who worked their ass off and did not bitch once that I saw.


November 28th, 2016 at 8:17 AM ^

is the play that I am talking about. They go Barrett for 5, sack for 3rd and 9, and then the circus Samuel play to get it to 4th and 1. There are OSU players who are seriously just grabbing jersey without fear of consequence. If you are wondering where the entire left side of our secondary went on that play, they were being tackled or held by the jersey.


December 3rd, 2016 at 2:43 AM ^

Though they might never admit it, in the NFL coaches study how officials (and I believe how individual officials) call holding carefully, so they can go up to the limit. It wouldn't surprise me if Ohio State (and probably Michigan) do the same.


Toasted Yosties

November 28th, 2016 at 8:20 AM ^

I'm not pissed at all about "The Spot," only about all the other obvious non-calls that should have done Michigan's way. Whether the ref was biased, knowing one is a lifelong Ohio State fan and that he wasn't allowed to ref the 2006 game provides appearance of bias. It looks bad. The B1G showed negligence in haphazardly selecting these refs.


November 28th, 2016 at 11:51 AM ^

that have become public since Saturday: We have no sway as fans in claiming bias except in making that case directly to the league office. It won't have any official bearing but it will certainly make the point better than not doing so.

The worst thing for the league to experience is the concern that its officials are incompetent or unfair. And even the suggestion or perception of bias is enough to satisfy that claim. Officals are essentially judges when it comes to calling a game. So, they are subject to the same ethical considerations when assigned, especially to a matchup of the magnitude of Saturday's game.

The ides that officials who have been oublicly linked to Ohio State either because of residency or personal interest conflicts,raises doubts about their bias regardless of intent and judgment, At the very least the oerception makes the league culpable for the assignment. And if you want ammunition, you don't beed to show cettain plays or calls. Just show them the disparity of yardage markoffs and penalties accrued by both sides.

That is something worth pointing out to the league because it's a black and white issue, not some subjective question about judgment of a certain play.

Yost Ghost

November 28th, 2016 at 2:16 PM ^

I'm fucking pissed about all of it! The refs sucked in every way suckable. That spot was atrocious. How can anyone call that a first down:

The holds, the PI's, the bogus penalties, the bad spot, the ref's OSU slanted backgrounds all adds up to something that is highly suspicious. How can one sit back and look at all this data and say with any assurity that all of this is a natural confluence of negative events?