[Bf-vfx] Plane Tracking naming

[Sergey Sharybin]

Hi,

I do not happy with calling it "corner pin" because it's not  corner pin at
all. You could (and probably even should) use more than 4 point tracks to
make plane estimation much more accurate. Also, point tracks have no
relation with corners at all: you could track points which are not corners
of your plane (we showed this in our video).

Further, using point tracks to define plane motion is one of possible ways
to do what you call "corner pin". Design is flexible enough, so in theory
you might use other kind of tracks (not just point ones) to define plane
motion. Simple example here could be using homography from point track to
define plane motion. It could work, but wouldn't be so much useful. Or it
also might be plane motion estimation from the mask (we already kind of
have this, but currently it's just proof-of-concept).

Another usage of plane track might be constraining point tracks to belong
to this plane while tracking them. Which means we might support
other-way-around usecase: you create point tracks, you create plane out of
them, and then starts tracking this point tracks taking plane constraint
into account.

So, long story short. We for sure might call it "Corner Pin" to match
"industry standard", but obviously Plane Track in blender is much more
generic and powerful entity. Generally speaking, it's just a plane which
might be defined in multiple ways, and none of them implies pinning
anything to something.

P.S. And i have no idea why one might be confused by term "new plane
tracker". It's never used in the interface and it's purely internal name
only. In the interface we only use "Plane Track" and i've described above
why renaming it to "Corner Pin" makes no sense.


On Tue, Aug 13, 2013 at 10:26 AM, David Jeske <davidj at gmail.com> wrote:

> On Mon, Aug 12, 2013 at 9:13 PM, Sean Kennedy <mack_dadd2 at hotmail.com>wrote:
>
>> Yes, but as Keir just pointed out, it is actually doing the same thing
>> under the hood.
>>
>
> I'm no expert, but what I see in Blender's new planar track looks very
> different from Mocha "under the hood". They are both tracking image
> patches, but Blender is tracking patches one-by-one and then fitting a
> plane-onto-them while Mocha appears to be associating affine trackers with
> a plane, and then solving (and potentially disqualifying) them together
> with the planar constraint.
>
> The difference in error bounds and flexibility between these two
> approaches seems very big. This is probably a big part of why Mocha is able
> to auto-generate the tracking patches.
>
> At least that's the way I see it.
>
> Which is not to say that the new Blender stuff is not awesome. It looks
> awesome. It just doesn't look like Mocha "under the hood". Of course what
> do I know, I didn't write Mocha, and all I saw was that video.. :)
>
>
>
> _______________________________________________
> Bf-vfx mailing list
> Bf-vfx at blender.org
> http://lists.blender.org/mailman/listinfo/bf-vfx
>
>


-- 
With best regards, Sergey Sharybin
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.blender.org/pipermail/bf-vfx/attachments/20130813/e4d41d73/attachment.htm