[OSM-talk] Three-dimensional aerial imagery

[Joseph Reeves]

> Basically, you put two images side by side, taken from slightly different
> angles. Look in the centre of the two images and "defocus" to a point beyond
> the page. Eventually you should see the image in full relief.

I've not heard of this approach before, but Stereoscopes are still
commonly used to produce a 3D image. Stereoscopic photography is still
very important, for example, in Archaeology / Heritage / lanuduse
characterisation. As far as I'm aware, there images are still being
produced (although they're a bit old fashioned now compared to
airborne LIDAR, etc), but I imagine they'd be pricey to get hold of.

In many places of the world (well, the UK at least) an enormous supply
of images will exist of buildings and landscapes that haven't changed
in a long old time; people have been using this technique since before
WWII, you just need to get access to some photos and decide on the
best Stereoscope -> Potlatch workflow. That could be the most
interesting bit of the entire project...

Cheers, Joseph




On 14 May 2011 23:54, Richard Bullock <rb357 at cantab.net> wrote:
>> I saw this news story about how three-dimensional aerial photos, viewed
>> with
>> special glasses, make it easier to pick out structures on the ground.
>>
>> <http://www.bbc.co.uk/news/magazine-13359064>
>>
>> I wonder if any such 3-d imagery is available today?  It would seem to
>> involve
>> having two cameras a set distance apart.  If OSM ever charters a plane
>> again, as
>> was done for Stratford-upon-Avon, England, a few years back, it might be
>> worth
>> taking two cameras instead of one.  In the meantime I guess we'll wait for
>> the
>> 3-d display Windows Phone to come out, with accompanying Bing Maps 3D.
>
> Stereoscopic images used to be very common and were, as far as I was aware,
> usually used to draw up contour lines for OS maps in the UK.
>
> You can see some examples here and on the next few pages
> http://rst.gsfc.nasa.gov/Sect11/Sect11_3.html
>
> They're a bit like "magic eye" images - and a lot of people should be able
> to see them without special glasses.
>
> Basically, you put two images side by side, taken from slightly different
> angles. Look in the centre of the two images and "defocus" to a point beyond
> the page. Eventually you should see the image in full relief.
>
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