Here's a technology I really haven't discussed much on the Virtual Earth for Public Sector blog (shame on me).

Until now, Photosynth was a  Live Labs research project that you could just get a glimpse of through a technology preview web site. But the Photosynth team was recently moved into the Virtual Earth team and has released an official Photosynth site that allows you to not only view Photosynth collections hosted there, but to add your own. Time to bring it to the attention of Public Sector customers, given its ability to allow for images collected in the field to be assembled in a manner to then allow the scene to be explored and navigated in a 3D like manner.

So what is Photosynth? Borrowing from the About Photosynth discussion on the site: It is a potent mixture of two independent breakthroughs--the ability to reconstruct the scene or object from a bunch of flat photographs, and the technology to bring that experience to virtually anyone over the Internet.  Using techniques from the field of computer vision, Photosynth examines images for similarities to each other and uses that information to estimate the shape of the subject and the vantage point the photos were taken from. With this information, we recreate the space and use it as a canvas to display and navigate through the photos.

Providing that experience requires viewing a LOT of data though—much more than you generally get at any one time by surfing someone’s photo album on the web. That’s where our Seadragon™ technology comes in: delivering just the pixels you need, exactly when you need them. It allows you to browse through dozens of 5, 10, or 100(!) megapixel photos effortlessly, without fiddling with a bunch of thumbnails and waiting around for everything to load.

The new Photosynth site hosts some great collections. You can check out some photos of Constitution Hall on the site here. Press the down arrow a few times to see the document in the context of the whole hall.  This  one of a Boulder tea house illustrates how a complex room can be quickly recorded and easily reviewed and shared, zoom back with the scroll wheel to see the whole room.  This Boulder aerial synth is wild ... it shows a great view of Boulder, about 400 of them actually, all automagically assembled into a 3D web accessible collection in a matter of a few hours.  Next best thing to buying an UltraCam, Microsoft's large format digital aerial camera, holding it out the window of your plane, and building your own Virtual Town!

[NOTE: Viewing the Photosynth site requires installation of the

The best part: Photosynth will be linking up more with Virtual Earth. For now Photosynth lets you geotag your Synth collections with Virtual Earth, just look for the little button next to the Synth’s viewer window.

Chris Pendleton provides an example of this, code and all, in his Virtual Earth Developer's blog. Meanwhile, you can see an instructional video on collecting imagery and creating the Synth collection.