... for thoses who give me image edition software, here's WIndows 10's camera in action, doing what I'm seeking as free software
@Miaourt Oh you mean being able to SPOT images of pieces of paper somewhere in a photograph? No idea there. I just drag a box around what I want.
Welcome to your niu world ! We are a cute and loving international community Ｏ(≧▽≦)Ｏ !