There are no free libraries that I know of.
Machine Vision and Object Recognition are
very advanced topics requiring tons of image manipulation techniques. This is something that VB.NET is ill-equipped to handle since it doesn't support unsafe code or pointers. C# or C++ are much better candidates for this type of work.
You can try and create your own, but I doubt you have the time to do it.
Start reading this pile of articles[
^].