Opencv : Some clue to detect a word pointed by an index finger on an image

I just want to do a quick project on my spare time :

I take a photo (with my webcam) of a page of a book with my finger pointing at a word on the page. Something like that:

I want to use opencv so I can isolate the word and translate it with OCR, etc ...

I cant' figure out exactly what to use in opencv to achieve this (I mean the "extraction" of the word in the complete photo), i read the tutorials but there is a lot of possibilities, so if someone can guide me by telling me what kind of functions do I need to use that would be kind :)

Thanks :)