Found In Space (On Flickr)

Jamie stumbled upon a writeup for all you astronomy and photography buffs out there (Perhaps my Dad or Uncle Jim are reading ;). From the writeup "The 'blind astrometry server' is a program which monitors the Astrometry group on Flickr, looking for new photos of the night sky. It then analyzes each photo, and from the unique star positions shown it figures out what part of the sky was photographed and what interesting planets, galaxies or nebulae are contained within. Not only does the photographer get a high-quality description of what's in their photo, but the main Astrometry.net project gets a new image to add to its storehouse of knowledge." Check out the Astrometry.net site for many cool pictures.

Comments

Astrometry.net and Comet Lulin

[fyngyrz]

I use them all the time; just shot comet Lulin, they did a great job of exact location:

Re:Very cool, but np-complete?

[kramer2718]

If it is done in polynomial time, then it would by definition be in P which means it would NOT be NP complete unless P=NP.

I think you are trying to ask how it could be done in less than exponential time (which is how fast the fastest algorithms to solve NP complete problems run).

I personally would expect an algorithm to perform the match would run in O(U*US+K*KS+UI*KI*U) where U=the number of unknown (ie flickr pictures), K=the number of known pictures, US=the average size of an unknown picture, K=the size of the average known picture, UI=the number of interesting things in an unknown picture and KI=the number of interesting things in a known picture. However, it would often run faster because it should be fairly easy to disqualify two pictures as containing any of the same interesting features.

Re:Photosynth for the sky?

[plover]

It's similar to Photosynth in that it finds the stars in the sky, but it only provides location information. It does not provide links (you can't navigate from photo to photo the way you can in photosynth.) Not to say they couldn't add that functionality later.

I think of this more like a real-life version of the "Astrogator" role on the space ships from old sci-fi stories, where they arrive at some spot deep in space, the astrogator looks around at the stars and determines exactly where they are.