There is a DLL wrapper made by someone to be used by autoit: search in google for "ImageSearchDLL".
Once you have downloaded it (it comes with a DLL and an AU3 file) try to make it work with autoit (I advice you to use bmp pictures for testing), just call Autoit script inside your C++ project

You can find tutorials on internet to how call autoit from visual studio (easy)
Edited: Or just call your DLL from c++ directly, but I didn't test it so I dont know if it is working!
Good luck