Hi Action,
There is not really a clear answer to this question,
In short yes it is possible.
However this is only going to work if you make a native app, because you need acces to the api of the phone to make pictures.
next to that you need to find a javascript libary that will analyse the picture, but i'm pretty sure there is one.
for example :
https://github.com/LazarSoft/jsqrcode greetings
Chris