Yet another idea for mobile phones...

The other day my mobile phone rung, and it was so loud that I had to run to it and silence it in order not to bother others. At that moment, I asked myself, why isnt' there an option that would allow me to set loudness of the ring tone to a level relatively to ambient. That should be doable, for example, by mobile phone turning on microphone before ringing and measuring noise in order to set loudness. Or, if that could be too long (and delay ring tone), it can start ringing quitely in increase loudness as it gains more measurements from surroundings.
Does something like that already exist? I now there is an option of ringing tone starting very quiet, and being stronger and stronger. But that's not it...