algorithm - How to correct shooting in touch-screen shooting games?

Assume a shooting game for iPhone that the character shoot toward where player has touched.

But as we know, There may be fault in touching screen by player and it conclude to bad game play and low fun.

So, How can I correct shooting method ?

Answer

I think when player touch a point, he target some thing that will place in a cone as below picture show.

So, we just need to check collision of objects in this cone, and if any exist, the player most probably decided to shoot at it.