Well, you've chosen one of the more complex and (to my mind) least "novice-friendly" aspects of NI's LabVIEW offerings, namely their Vision packages. At one end, there are the "Express VI" tools such as the Vision Assistant, designed to allow the novice to do "simple things" without having to understand what is going on "under the hood". It is a nice, convenient way to insulate the Beginner from the true power and beauty of LabVIEW, and instill a false notion that "LabVIEW is Easy, I don't need to learn anything, I can just throw a few functions and wires down and I'll get my answer".
Then Reality sets in. At the other end of the Vision spectrum is the Vision Development Module, which contains a whole lot of functions that are designed to do pretty sophisticated 2D Image Processing (and which comes with a separate License, as I recall). These routines have a lot of power, and can probably allow you to carry out the task you pose, but will require some significant effort on your part.
It may be time to head for the Library (or the Web) and get some ideas about the kinds of algorithms you may need to carry out the task you propose. This is doable, but it is definitely not trivial ...
Bob Schor
