Is Matthias-Fauconneau' Tracking Code In Qt-Tracker Correct?

[Huang ZhiYong]

Hello Keir,
I read the tracking code in Qt-Tracker. I think it was
implemented as exhaustive searching the best affine transformation
warped reference patch to match in the next image. Although the
tracking result looks good,
I still think it is not correct. How do you think that?

[Matthias Fauconneau]

Hi,
I'm curious to know what do you exactly mean ?
The affine tracker worked fine in my tests (cf video).

[Keir Mierle]

The affine tracker (SAD) does an exhaustive search for a good translation match, then does coordinate descent with some regularization to find a good affine solution.

Keir

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[Matthias Fauconneau]

Hi Keir,

While you're here, Sergey told me that he didn't want to have affine
tracking in blender because he wasn't sure the interface wouldn't be
changed.
Any plans to make the integration happen ?
It would be a shame to see this code unused any longer :/.
Especially with the drifting issues non-affine tracking has.

[Keir Mierle]

On Tue, Dec 6, 2011 at 2:47 AM, Matthias Fauconneau <matthias....@gmail.com> wrote:

Hi Keir,

While you're here, Sergey told me that he didn't want to have affine
tracking in blender because he wasn't sure the interface wouldn't be
changed.
Any plans to make the integration happen ?

Yes, we're definitely going to add it.

 

It would be a shame to see this code unused any longer :/.
Especially with the drifting issues non-affine tracking has.

I added a new hybrid tracker to Blender that's not yet reverse-merged into libmv which uses a brute force SAD search for the initial guess then does ESM refinement. It works really well. However, we'll have to add affine tracking at some point. The tracking setup in blender isn't currently well set up for supporting affine, which involves e.g. showing the affine-shifted pattern and storing the affine transforms in addition to the tracking. Also, we will need a facility to support tracking any combination of scale, rotation, skew, perspective.

Keir

[Julien Michot]

Well done for the ESM tracking!

Julien