[OSM-talk-nl] Mikrokopter Aerial photography

Stefan de Konink stefan at konink.de
Sat Oct 31 15:51:27 GMT 2009


On Sat, 31 Oct 2009, Valent Turkovic wrote:

> On Fri, 30 Oct 2009 13:36:14 +0100, ce-test, qualified testing bv - Gert
> Gremmen wrote:
>
> > I suggest that you climb a tower of flat and make some 45 degree
> > pictures...
>
> Arent photos from 45 degrees much harder to use than aerial photos shot
> from above?
>
> What should I do after I shoot photos from 45 degrees angle? How do I
> make orthophotos from them?

Basically define a shape in the ground plane you photograph, a square is
usually the most suited. you know that the square on the photo is a
projection from the square that you see from the top.

by selecting the square, it is possible to create a transformation matrix
that tilts and rotatess that square back. at the cost of non-uniformpixel
density. tricky parts are lense correction.

tools like efoto and the opencv code tijs created for signfinder do this
already. what lacks for us is the  GPS (outer corner alignment) to put it
into a WMS using a world file.


Stefan





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