[mythtv-users] OT: How is this inline done?

[Joseph Fry]

On Sun, Jan 17, 2016 at 9:23 PM, Mike Hodson <mystica at gmail.com> wrote:

> On Sun, Jan 17, 2016 at 6:00 PM, Jerome Yuzyk <jerome at supernet.ab.ca>
> wrote:
> >
> >
> > I don't even know how to ask a good Google question for this, and there
> > appear to be some broadcast veterans/nerds here, and it's quiet, so I
> ask.
>
> And I'm glad you did; it allows me to take the time to regurgitate
> what I've found out over the years on this subject.
>
> >
> > I understand how green-screen works, but there is a new form of inline
> > static advertising overlay (or insertion) that I can't understand using
> > green-screen. Up here in Canada we get to see ads for Canadian Tire in
> the
> > SuperBowl or MLB (baseball) games, for example.
> >
>
>
> This is decidedly not green-screen; its either camera angle
> correlation, or, texture mapping, onto a 3d virtual arena model that
> they scanned, likely with LIDAR, to get everything precise.
>
> At first, when I saw the "first and 10 line" on NFL games, I thought
> they were doing some very interesting texture-mapping with a computer,
> to line up the image in real-time and also to stretch it for
> perspective. Nope, the "first and 10 line" overlay image was made
> possible by very precise servomotors sensing where the cameras were
> pointed, and correlating it in a computer.
>
>
> >
> > It's on the glass behind the goalie nets in NHL games. I first noticed
> > Fox-LA doing this a couple years ago in Kings games and now it's come to
> my
> > hometown.
>
> There were a couple of competing firms, but now the leader in this 3d
> mapped arena stuff is Sportvision. They even highlight the type of
> advertising you mention on the glass backing behind the goals.
>
>
> http://mentalfloss.com/article/27009/explaining-magic-yellow-first-down-line
> https://en.wikipedia.org/wiki/Sportvision
> http://ethw.org/Sportvision
>
>
> >
> >
> >
> > What I can't figure out is what are the overlay/insert "hooks" that one
> can
> > do with glass panels and stanchions? Is there something embedded in the
> > glass? The four corners of the ads are on glass, so it's not something
> the
> > stanchions are doing. As for MLB, ads aren't seen in replays, so the ads
> > have to be on a separate stream merged into the live feed.
>
> With the increases in CPU horsepower in the recent years since the
> simplistic 'first and 10 line', Im almost certain now that they are
> using 3d texture maps of the arena and correlating points on their
> models with visuals taken by the cameras.  If they're still doing
> camera tracking, then perhaps thats just worked for them forever and
> they know it well; 3d texture mapping is used in all the post
> production stuff now to create convincing, and properly
> moving/tracking 3d virtual sets.
>

There is one other layer to the 3D mapping though, they also detect (likely
due to some comparison algorithm) where forground objects exist, and don't
draw the image there... this way it doesn't obstruct the action.  I have
noticed once or twice, when a player has nice green grass stains on their
pants, sometimes the line will actually go through their leg, like a green
screen.

I have played with difference masks before, and I am impressed how well
theirs work considering that lighting changes through the course of the
game.  Sometimes in a span of seconds as a cloud goes by, or the lights
come on... Their algorithm must be pretty powerful to not have parts of the
logo cut off due to players shadows and stuff like that.

Amazing that they can do in realtime, what it used to take seconds to do in
photoshop.
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