How does google know if I type in redflower.jpg I mean Red Flower?

I'm curious what the programming terms or methodology is used when Google shows you the "did you mean" link for a word that is made up of multiple words?

For example if I type in "redflower.jpg" It knows to break that up into Red Flower Is there a common paradigm for doing that sort of operation? Would a Lucene se开发者_如何学Carch give you that?

thanks!

If google does not see a lot of matching results for reflowers.jpg, it might then try to cut the words in multiple words until it finds a lot of matching results.

It might also recognize the extension (.jpg), recognize the image extension and then try to find images with the similar name.

If I would have to make an algorithm like this, I would use an huge EXISTING database (either a dictionary or a search engine) and then try what I said in the beginning of my post.

Perhaps they could to look at what other people do when they have searched for redflowers.jpg? Maybe a number of people searched for "redflowers.jpg", didn't click on any links, and then searched for "Red Flower" and found some results worth clicking on.

Of course they would have to take into account that the queries are similar (contain matching strings), otherwise some strange results might appear.