Image Pattern Recognition

I am looking for a vb.net? function that i can pass two images into, a source and a target image, and output an? integer into a public variable. The source image will be a small section of the target image. The main purpose is to find out if the source image is contained within the target image, to a level of accuracy where an integer is output, eg. 100% sure the image is contained, 95% sure the image is contained, 4% the image is contained, However the target image may be resized, or be of a lower quality, so some kind of fuzzy comparison is needed. The two images will be of varying sizes. I need this to be quite a fast process, taking a maximum of 5 seconds per comparison, and the funtion must be able to run repeatedly. A good example is shown at the bottom of the page linked below, although this only shows if the picture hasn't been resized. It is this kind of comparison that is needed, however i include this mainly as a point of reference, rather than a requirement of the function. Please feel free to ask questions! Example found at the bottom of this page; <[login to view URL]> ## Deliverables The machine that will be used to test (and ultimately run) the code is as follows; (i include this so that the 5 second rule can be estimated / calculated) XP Pro SP3 Pentium 4 2.8Ghz 3Gb Ram Please dont feel influenced by the example URL, i just found this example and thought it might jump-start somesones brain!