
Isolating Football Player Movement by Eliminating Camera Motion - tantalor
http://phdfootball.blogspot.com/2014/09/isolating-player-movement-by.html
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valgaze
This technique reminded me of BriefCam-
[http://briefcam.com/](http://briefcam.com/)

They figured out how to "summarize" video surveillance footage by attaching a
hovering timecode to any object moving through the frame and then later it
overlays several hours of footage into one video.

Pretty trippy:
[https://www.youtube.com/watch?v=fISfDd35sXU](https://www.youtube.com/watch?v=fISfDd35sXU)

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StavrosK
Oh wow, that's an amazing idea and great execution as well.

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nostromo
People do image stabilization manually on reddit and the results are amazing.

Ex:
[http://gfycat.com/CriminalAromaticEsok](http://gfycat.com/CriminalAromaticEsok)
or [http://i.imgur.com/ErQRMrV.gif](http://i.imgur.com/ErQRMrV.gif)

[http://www.reddit.com/r/ImageStabilization/](http://www.reddit.com/r/ImageStabilization/)

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wingerlang
Not fully manual is it?

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euroclydon
If you sign up for NFL Replay, you can watch "the full 22" videos during the
week. It's inexpensive. I hate that they don't show this view on regular
broadcasts. It's such a big part of the game, to know what type of coverage
the DBs are in when a play starts. To know whether the QB made a good read,
you'd have to see the coverage on all of the receivers.

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minikites
I assumed it had something to do with not providing that information to the
currently playing teams while they are currently playing, are teams allowed to
have "spotters" up in the stands to get an overhead view?

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at-fates-hands
Interesting article from 2011 talking about why the NFL didn't give the "all
22" view to the teams:

[http://online.wsj.com/news/articles/SB1000142405297020371620...](http://online.wsj.com/news/articles/SB10001424052970203716204577015903150731054)

"Lonnie Marts, a former linebacker for the Jacksonville Jaguars, says there
are thousands of former NFL players who could easily pick apart play-calling
and player performance if they had access to this film."

And another one for the conspiracy buffs:

"The NFL makes a handful of plays from the All 22 available on its web site
for a fee, but they're often so blurry the players' numbers aren't visible."

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btown
Very interesting! With some manual or automatic annotation, this is one step
closer to spatiotemporal player data, which opens up whole new boundaries of
analysis.

As a point of comparison, there's a private NBA dataset (based on imaging and
manual annotation) which shows the locations of shots made, annotated with the
player name and whether they failed or succeeded - from this, you can do
really cool things like Miller et. al. 2014 [1], who use dimensionality
reduction to find patterns in players' preferred shot locations, potentially
allowing you to create teams whose offensive abilities are complementary from
a spatial perspective.

[1]
[http://jmlr.org/proceedings/papers/v32/miller14.pdf](http://jmlr.org/proceedings/papers/v32/miller14.pdf)

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kendallpark
+1 +1 +1

As a programmer, football player, and football coach, I've been searching for
something like this for a long time.

I think the biggest advancement in technology would be figuring out what plays
are being run and in what scenarios, and analyzing them for patterns and
weaknesses. Like knowing that the opposite team runs GAT to the wide side of
the field 95% of the time. Or figuring out individual players' tendencies to
give more detailed read keys to the defense.

The problem is, I think, that a lot of the critical info is inside the tackle
box with the actively engaging linemen. It seems it would be tricker to track
ten or so players in such close quarters.

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fmela
Very neat. It's interesting to see the NFL logo from the corner of the
original footage moving around in the stabilized footage. Future feature:
automated watermark removal?

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aganders3
As the watermark is static in the original footage, it should be easy to
remove before processing.

I'd like to see the players remain, perhaps somewhat transparent, once they
are cropped out of the actual shot. Otherwise the zoom/pan just erases them.

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dougabug
This seems like just background subtraction. I used this on soccer videos
eight years ago using some robust optical flow code from Michael Black to
estimate the background motion and suppress it, leaving the foreground (i.e.
the player).

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AndyNemmity
Fantastic Blog, I run an online football game and try to use advanced
analytics to generate proper games. Going to rummage through your archive and
see if there's anything usable for me, trying to generate accurate games.

Thanks for the work.

Edit: Example, this blog post is amazing for my work.
[http://phdfootball.blogspot.com/2014/03/classifying-wrs-
tes-...](http://phdfootball.blogspot.com/2014/03/classifying-wrs-tes-and-rbs-
by-where.html)

You provide the code you ran(!!!) so I can run it myself against the data I
generate, and then validate that I am matching the actual data.

Incredible. Going to continue moving through the article, but that's at least
one piece of data I can use to compare in a way I never have before.

Edit 2: [http://phdfootball.blogspot.com/2013/10/qbs-dont-have-
passin...](http://phdfootball.blogspot.com/2013/10/qbs-dont-have-passing-
rhythm.html) is interesting, but you have to do any QB completion data with
completion % based on distance thrown. QB completion is meaningless without
incorporating distance.

Edit 3: [http://phdfootball.blogspot.com/2013/09/not-all-fumbles-
are-...](http://phdfootball.blogspot.com/2013/09/not-all-fumbles-are-created-
equal.html) is data I can incorporate today. Currently I have a simple random
recovery generator that is 50/50 due to FO's essentially random remarks
regarding fumbles.

Now I will change that to be a formula based on field position. That is direct
improvement to my work, thank you!

Edit 4: [http://phdfootball.blogspot.com/2013/08/quarterback-
rating-i...](http://phdfootball.blogspot.com/2013/08/quarterback-rating-i-
year-to-year.html) is again plagued by completion %, which QB rating uses.

Many Qbs improve or decline their QB rating, while actually being better QBs
or worse depending on the yardage thrown. I could give many examples of QBs
with decent Completion %s that are horrible because they throw short passes.

Not bad, just another note that distance is the foundation of completion % and
without that, it's essentially bad data.

One interesting analysis would be plotting the distance thrown on passes over
careers, and see if this is a good indicator of improvement.

Edit 5: [http://phdfootball.blogspot.com/2013/06/field-position-
and-s...](http://phdfootball.blogspot.com/2013/06/field-position-and-
scoring.html) is interesting, I distinctly remember that Completion % per
yardage drops significantly inside 20 yards. I don't have the data on hand,
but that's an interesting wrinkle to consider. I think that may have been FO.

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philsnow
> Edit 2: [http://phdfootball.blogspot.com/2013/10/qbs-dont-have-
> passin...](http://phdfootball.blogspot.com/2013/10/qbs-dont-have-passin..).
> is interesting, but you have to do any QB completion data with completion %
> based on distance thrown. QB completion is meaningless without incorporating
> distance.

I had a similar thought; seems that he should bucket at least by remaining
yards to get the first down as well as field position. Imagine an 8-yard pass
completion after a 1st and ten: many teams will attempt a deep pass, hoping to
pick up the first down with a short play in case of an incompletion. That deep
pass is a very different play and probably has a different completion
likelihood.

Likewise, consider passes from your own 20 vs their 20 (that is, 80 yards of
field left before the end zone vs 20): my intuition says that the latter pass
has lower likelihood of completion, because the field is shorter and the
defenders have less ground to cover.

So, it might actually be that "rhythm" exists, but only in long field
positions or only on long drives.

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jonifico
Is this technology on the players' shoulder pads something like Adidas'
miCoach?

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thanatropism
Disappointed to see this is about "American Football", not "Football".

Seriously, I'm curious about the ever-stricter rules about contrasting
uniforms in football outfits - enough that national sides can't play in their
classical colors anymore, and club teams have four to six alternate uniform
sets; I thought that was to facilitate the automated analysis of games, as
I've already seen some contrast-jacked still shots used to overlay tactical
diagrams.

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_pferreir_
I can't see why this was downvoted. I felt exactly the same.

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mwfunk
As someone else pointed out, there is no one sport that has a monopoly on the
term "football". Also, complaining about Americans who refer to American
football as "football" often sounds like thinly veiled xenophobia disguised as
pedantry, a la "here's one more thing I hate about those stupid Americans..."
It's such an odd thing to complain about that it comes across as the tip of a
hate iceberg rather than an actual complaint about terminology.

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mikeash
Can you imagine applying this to other countries? "Oh those stupid Chinese,
they call their country 'Zhongguo', but it's clearly 'China.'" Seems that
labeling country-specific language variations as "wrong" is acceptable only
for the USA.

