object recognition

Basically what I want to do is create a program that is given a picture and can classify various objects (chair, desk, book, plant, etc) in the picture and attempt to estimate distance between various objects. Does anyone know of any tutorials or where I could start to get information on this subject.

www.google.com

try searching for object recognition?

I know the FBI or CIA or some organization using similar technology to identify desktop users (don't think it worked well enugh though) and to compare pictures of saddam....but i dont' think they'll just give you their source code.