[OAM-talk] open source orthorectification for grassrootsmapping.org

[Jeffrey Warren]

I started with Map Warper (warper.geothings.net) but i found that manually
warping in photoshop (just using the distort tool) yielded much better
results, and was actually faster. This is mainly because of the kinds of
images (and scales) you get from balloon mapping. See:

http://www.flickr.com/photos/jeffreywarren/sets/72157623196104469/

Thanks for the link - i'll take a look. I'd been using SIFT but haven't
fiddled with it enough to know how to rectify against control imagery. It
does a pretty good job for stitching, of course - though it doesn't
accommodate images at different scales that well - something which happens a
lot with balloon imagery.

<http://www.flickr.com/photos/jeffreywarren/sets/72157623196104469/>Best,
Jeff

On Wed, Feb 17, 2010 at 2:40 PM, Marc Pfister <MPfister at enplan.com> wrote:

>  There’s some or all of the functionality in GRASS, OSSIM, E-FOTO, and the
> NASA Vision Workbench. Making it all work as a webservice sounds tough to
> me.
>
>
>
> I think you’ll also have some challenges it that you probably only have low
> resolution and quite possibly low accuracy orthoimagery to control against,
> coarse (if any) DEMs, and a camera with a short focal length, no fiducials
> or calibration report. I wonder if simple warping will get you just about as
> far in terms of accuracy.
>
>
>
> At Random Hacks of Kindness I started on some code that used SIFT to try to
> match UAV photos to control imagery and generate a GCP list that could be
> fed into gdalwarp. The UAV imagery did have some rough GPS positioning that
> limited the search space for the SIFT algorithm. It’s still (argh)
> unfinished, but you can see the start here:
>
>
>
> http://github.com/drwelby/UAV-Ortho
>
>
>
> -Marc Pfister
>
>
>
>
>
>
>
> *From:* talk-bounces at openaerialmap.org [mailto:
> talk-bounces at openaerialmap.org] *On Behalf Of *Jeffrey Warren
> *Sent:* Wednesday, February 17, 2010 8:36 AM
> *To:* geodata at lists.osgeo.org; talk at openaerialmap.org
> *Subject:* [OAM-talk] open source orthorectification for
> grassrootsmapping.org
>
>
>
> Hi all - I'm looking for an open source way to do automated
> orthorectification as a web service to support
> http://grassrootsmapping.org balloon/kite mapping imagery.
>
>
>
> Something that would generate GCPs and stitch imagery, and (even better)
> perhaps generate tiles.
>
>
>
> I'm a bit new to rectification, any suggestions?
>
>
>
> Thanks,
>
> Jeff
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://host134.hostmonster.com/pipermail/talk_openaerialmap.org/attachments/20100217/a4ecf5a7/attachment.html>