Pattern recognition (detecting pattern that do not match original pattern) OpenCV

I would like to create an android application that can recognize a custom pattern and if that pattern detected do not match, it will highlight that particular pattern that do not match. I am using OpenCV

Currently I am trying to write the codes in C++ Visual Studio 2008.

What type of algorithm I can use to achieve this in real time camera.

Do I need to write my own training system like the opencv's traincascade.exe file in order to detect the pattern that do not match?

Any tutorials or source codes that I can refer to as a guide?