[OpenDroneMap-dev] Image Correction

[Stephen Mather]

It seems that the portion of the CMOS used, or effective chips size, would
be different between video and stills, so calibration would be different
for video and stills.

On Thu, Mar 19, 2015 at 11:51 AM, Alex Mandel <tech_dev at wildintellect.com>
wrote:

> You don't want a video, you want still images. I can upload some later.
> The problem with the video is that it's much lower resolution than time
> lapse shots from the same camera and you end up grabbing frames from it
> anyways.
>
> Measuring the checkerboard loss from really close up shots is exactly
> how I guessed the new sensor size.
>
> Thanks,
> Alex
>
> On 03/19/2015 05:41 AM, Cole wrote:
> > I was just going to email the list about that.  I would like to make a
> test
> > use case for this.  Since the ARDrone is probably not within our normal
> use
> > case, and I do not own a GoPro, would somebody be able to take a video
> of a
> > checkerboard pattern (
> >
> http://wiki.ros.org/camera_calibration/Tutorials/StereoCalibration?action=AttachFile&do=get&target=check-108.pdf
> )
> >  and share it.  Make sure you pan the camera so every part of the sensor
> is
> > covered by the pattern in at least one frame.  Orientation, skew, etc
> does
> > not matter.  Make sure you get it as some different distances as well.  I
> > think we can also calculate the CCD width of the cropped image based on
> the
> > width of the checkerboard cells.
> >
> > The next logical progression in this work would be to take video and find
> > the minimum number of overlapping frames to create a desirable result --
> > using RANSAC.  So if y'all have some aerial gopro video footage with the
> > exact same camera, I would appreciate that as well.
> >
> > As the I have a use case for my application with video inside and outside
> > of ROS, I will be posting a test case using the ARDrone, which uses a
> > wide-angle camera.
> >
> >
> > v/r
> > NJK
> >
> >
> > On Wed, Mar 18, 2015 at 11:33 PM, Stephen Mather <
> stephen at smathermather.com>
> > wrote:
> >
> >> Very interesting, I'll check it out. I'm thinking through the
> implications
> >> of no cropping, and while this won't affect matching, it likely will
> cause
> >> issues at the texturing stage, so a default cropping with optional
> no-crop
> >> would be useful. I assume a crop will affect the effective CCD width, so
> >> that will need calculated.
> >>
> >> Is there any sharable wide-angle data for testing this?
> >>
> >> Thanks,
> >> Best,
> >> Steve
> >>
> >>
> >>
> >> On Tue, Mar 17, 2015 at 4:09 AM, Cole <colek42 at gmail.com> wrote:
> >>
> >>> I have a image calibration class up at
> >>>
> >>>
> >>>
> https://github.com/colek42/TrackIt/blob/master/catkin/src/stabilize/src/calibrate.py
> >>>
> >>> It is working great.  I'll add a main function and comments in the next
> >>> day or so and do a pull request.  I am using an ARDrone camera, but
> this is
> >>> agnostic to the type of camera.  There is no cropping done, so the
> edges
> >>> are curved with a black background.  If it needs to be cropped let me
> know
> >>> and I'll add an arg for that.  The interface also needs a bit of work.
> >>>
> >>> I was expecting the result to be symmetric, they are not.
> >>>
> >>> v/r
> >>> NJK
> >>>
> >>>
> >>>
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> >>> http://lists.osgeo.org/cgi-bin/mailman/listinfo/opendronemap-dev
> >>>
> >>>
> >>
> >
> >
> >
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> >
>
>
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