That's a fun (and useful) project and that is a Computer vision project (artifical intelligence applied to real images). The reference open source framework is OpenCV. You have all the needed tools and algorithms included for your project. I won't give you a recipe since it seems it would be your hobby project.

Eventually you might want to use the python interface to call opencv functions, it might be a bit faster to write the program; however writing in c++ is perfectly fine to me, you "just have to" deal with pointers and manage memory yourself, which can be needing skills. In opencv you have several GUI integrations (Qt, winforms, etc), and c++ and python are the right languages (in particular for PyQt and Qt).

To prototype new algorithms, the professionnal practice is to work with Matlab. Prototyping with Matlab is the fastest. It is also the most expensive in terms of money.

Eventually, if you want to use a deep learning framework, you have Torch and Caffe. OpenCV can load Caffe models. But in my opinion, classical computer vision should be sufficient. In the deep mearning case, you don't need Matlab, even though they have since 2017b deep learning integration, which can be a bit faster for prototyping.

The right engineering pratice is usually to prototype fast (matlab, or python, then c++/openmp/cuda), then to go for heavier work with c++ (you can export your matlab functions into c++). Except for deep learning, you go directly with Lua (or Matlab), since it's super heavy on the GPU (without which you can forget doing deep learning), and you let big compagnies such as Nvidia do the low level optimizations in their drivers.

Good luck with your project !