[Kwiver-users] Important

Wed Dec 21 17:15:41 EST 2016

Please reply to the kwiver-users address as well as mine. Someone else on
the list may chime in with additional info.  My answers are inline below.

On Wed, Dec 21, 2016 at 4:11 PM, Sukhad Anand <sukhad.anand at gmail.com>
wrote:

> I am using the first dataset in the list "Horizontal mappong with eBee".
>

I'll try to process that and see what issues I have.

>
>
> Is it possible to obtain the trajectory of the camera on the image itself?
>

Yes it is, up to a similarity transform.  In other words, you won't know
the final scale, geo-position, or geo-orientation of the solution without
either GPS or ground control points, but you can get a relative trajectory
of the cameras.

>
> For what purpose is .pos file given as input in bundle_adjust_tracks?
>

The .pos files are currently the format for input metadata (GPS, INS) that
we can use for initialization and geo-location.  These are optional inputs.

>
> Is it possible to use the tool for  real time navigation?
>

No, not yet.  Our current focus is offline optimization for best quality 3D
reconstruction.  We are interesting in exploring real-time in the future,
but don't have any funding to do that at the moment.

>
> How can i produce geo coordinates using current camera view?
>

You'll need either GPS measurements for some of the images, or you'll need
to manually select some ground control points.  This will allow you to get
a geo-registered result.  Unfortunately, that part is not very intuitive or
well documented at the moment, but we are working on improving it.

>
> How to load my own plugins?
>

The plugin framework is still evolving (this is a relatively new and
quickly growing project).  In MAP-Tk 0.8.0 and 0.9.0 the plugins are
installed in ${INSTALL_PATH}/lib/maptk.  Everything in that directory is
loaded.  You can add plugins there or specify additional paths with the
environment variable KWIVER_PLUGIN_PATH.  As of the master branch of MAP-Tk
(and future releases) all the MAP-Tk plugins have moved into the KWIVER
project.  The install path might change before the next release, but the
environment variable is still the same.

The next obvious question is "How do I create my own plugin?".  We'll need
to write a blog post on that in the future and put together a template to
get people started, but that hasn't happened yet.  For now, the best way is
to look at the existing plugins.  These plugins have been called "arrows"
after moving into KWIVER.

>
> It would be a great help if you could provide a good tutorial link for the
> tool.
>

Here is one tutorial:

https://blog.kitware.com/getting-started-with-map-tk-for-aerial-photogrammetry/

and this one describes more recent changes:

https://blog.kitware.com/map-tk-0-9-0-release-provides-dense-3d-better-loop-closure-and-opencv-3-support/

We'll try to release more tutorials and updates like these in the future as
things continue to change.

--Matt

>
>
> On Wed, Dec 21, 2016 at 10:41 PM, Matthew Leotta <matt.leotta at kitware.com>
> wrote:
>
>>
>> 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
>>
>>
>> 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>
>> 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>
>>> 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.
>>>>
>>>> _______________________________________________
>>>> Kwiver-users mailing list
>>>> Kwiver-users at public.kitware.com
>>>> http://public.kitware.com/mailman/listinfo/kwiver-users
>>>>
>>>>
>>>
>>
>>
>
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