[OpenDroneMap-dev] Image Correction

[Stephen Mather]

Hi Cole,

Have you had time to do more with this? With Daryl, Alex, and others
proposing a python port, perhaps we could integrate it, and do distortion
correction at the front end of the processing chain for images that require
it by using this class + a user-built calibration library.

Thoughts?
Best,
Steve



On Thu, Mar 19, 2015 at 12:58 PM, Stephen Mather <stephen at smathermather.com>
wrote:

> 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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>> >>>
>> >>>
>> >>
>> >
>> >
>> >
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>> >
>>
>>
>
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