integralhistogram is a Processing library.
Here you can see the library in action, searching and finding 4 different target images on a video; that's a real time library's test. Enjoy!
(the video is home-made ^^)
P.S: you can find the code on our homepage: http://www.inthistogram.altervista.org
and the library code at: http://bitbuket.org/giova/integralhistogram