[Kwiver-users] Important

[Matthew Leotta]

> On Dec 21, 2016, at 10:42 AM, Sukhad Anand <sukhad.anand at gmail.com> wrote:
> 
> Matt,
> 
> I am using MAP-Tk 0.8.0.

I suggest you use the latest MAP-Tk, 0.9.0.  It has options for much improved loop closure that you will probably need.

> 
> This is the link for the dataset which i am using.
> https://www.sensefly.com/drones/example-datasets.html <https://www.sensefly.com/drones/example-datasets.html>

Thanks for the link.  Which specific data set are you trying?  It would be helpful to know in order to reproduce this.

> 
> Is it possible to run this tool on a drone making linear motion instead of orbital motion as in kwiwer_fmv_set1 ?

Yes, but we’ve done far less testing on that type of data.  Also the current pipeline is optimized for video instead of images capture at a lower frame rate.  You will likely need to adjust the configuration settings to make it work in these cases. 

> 
> i would be obliged if you could provide the link for detailed explanation of the loop closures used by MAP-Tk

There a multiple algorithms that you can configure for different needs, and the whole framework is extensible so you can even write your own loop closure algorithm to plug in.  The current “best” available algorithm (as of 0.9,0) is a key frame based method.  It’s an image-to-image matching approach.  In short, the algorithm matches each frame to the previous frames and a list of key frames.  When none of the key frames match it establishes a new key frame.  it’s a bit more complicated, but that’s the basic idea.

If I can find some time I’ll try get things running on these sensefly data sets.

—Matt

> 
> Thanks
> 
> On Wed, Dec 21, 2016 at 7:30 PM, Matt Leotta <matt.leotta at kitware.com <mailto:matt.leotta at kitware.com>> wrote:
> Sukhad,
> 
> My guess is that the maptk_track_features tool is not finding enough features or enough feature matches.  Which version of MAP-Tk are you using?  What is the public dataset?
> 
> --Matt
> 
> On Wed, Dec 21, 2016 at 3:12 AM, Sukhad Anand <sukhad.anand at gmail.com <mailto:sukhad.anand at gmail.com>> wrote:
> when i run track_features on a public dataset , after each frame it outputs writing invalid homography.
> And when i run adjust_track then it displays this :
> 
> no landmark projections for new camera
> current reprojection RMSE: -nan
> frame 0 - num landmarks = 0
> frame 0 uses reference 0
>  and further processing does not takes place as if the program goes into infinite loop.
> 
> Please suggest how to get rid of such problems.
> 
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