[Soc-2011-dev] Weekly Progress Report #13 - libmv Tracker
mierle at gmail.com
Fri Aug 19 23:16:32 CEST 2011
Great work Matthias! Hopefully once things are cleaned up I can lure you
back to work on fun stuff :)
On Fri, Aug 19, 2011 at 1:17 PM, Matthias Fauconneau <
matthias.fauconneau at gmail.com> wrote:
> We have affine tracking !
> Complete formatted version of the report (with screenshots):
> === Week 13: August 12 - August 20 ===
> * Lens distortion estimation.
> ** Complete reference implementation.
> ** Create and document a simple C interface.
> * "Moravec"(SAD) detector.
> ** Detect features which are unlikely to drift.
> ** Detect features similar to a given pattern.
> * Affine Tracking!
> ** Support in Tracker API.
> ** Support in Qt Tracker UI.
> ** Implemented for SAD Tracker using coordinate descent.
> ** Optimize integer pixel search.
> ** Tweak coordinate descent.
> ** Added regularization (area and condition number).
> * Add Laplace filter to be used to avoid failure from smooth lighting
> * Improve UI.
> * Document API.
> The SAD detector is more suited to tracking since it try to choose
> patterns which are unlikely to drift by computing SAD with neighboring
> It could be improved to better avoid edges.
> The SAD Tracker now supports full affine transforms (rotation,scale,skew).
> This was necessary to make tracking usable without adapting at each frame.
> Since there wasn't much time left for tracker improvements (the KLT
> tracker was good enough until recently), I implemented a simple
> brute-force solution:
> To optimize all 6 affine parameters, I use the coordinate descent method.
> While this made the tracking 10 times slower, there is much potential
> for optimization if ever necessary. In any case, the performance is
> still comparable to the slow pan only KLT tracker (10ms/marker).
> === Later ===
> Blender will need to integrate straight line lens distortion
> estimation, image distortion/undistortion, make affine tracking
> interface easy to use and expose the laplace filter.
> Libmv will need to be refactored to remove all unused and unsupported
> It should focus on its initial goal: structure from motion and
> multiview reconstruction.
> This simplification of libmv design will ease the maintenance, reduce
> compile time,
> decrease binary size, increase performance, and help attract contributors.
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