image matching algorithms

[Yu-Xi Lim]

Daniel Fetchinson wrote:
> There are a number of free tools for image matching but it's not very
> easy to decipher the actual algorithm from the code that includes db
> management, GUI, etc, etc. I have my own image database and GUI so all
> I need is the actual algorithm preferably in pseudo code and not in
> the form of a research paper (from which I also found a lot but since
> I'm not that much interested in the actual science of image
> recognition this seems like an over kill).

I'd recommend SIFT. There's quite a bit of information on SIFT. In most 
cases, they don't cover the background science too much, but are still 
heavy on the math. Pseudo code is hard to come by since it will take 
many lines of pseudo code just to express one concise mathematical 
equation. There are however many links to implementations in various 
languages on the Wikipedia page.

http://en.wikipedia.org/wiki/Scale-invariant_feature_transform

I have had good experiences with SIFT for feature extraction from images 
(I have used it for panorama stitching and robot mapping). It's 
insensitive to scale and rotation. Note that it is a patented algorithm 
and this may (or may not) pose a problem for you.