Projects using quadrotors to do things like fly cooperatively and do acrobatics [1,2] will often use high speed motion capture systems with multiple fixed cameras. This decouples the problem of perceiving the environment from the problem of responding to the environment.
More broadly in robotics there are plenty of people working on ground-based robots that don't rely on multiple fixed high speed cameras - self-driving cars [3] would be one example. There are also people working on cooperative ground based robots that don't rely on multiple fixed high speed cameras - for example, the RoboCupSoccer Middle-Size League [4]. There are also people working on quadrotors that don't cooperate/do acrobatics and who don't rely on fixed vision systems - for example people working on autonomous quadrotor mapping [5] and using IMUs and on-robot vision [6].
Yes, but none of them are (permanently) aerial and some of them use internal combustion for power. Computation requires weight and energy, and computer vision requires lots of computation.
More broadly in robotics there are plenty of people working on ground-based robots that don't rely on multiple fixed high speed cameras - self-driving cars [3] would be one example. There are also people working on cooperative ground based robots that don't rely on multiple fixed high speed cameras - for example, the RoboCupSoccer Middle-Size League [4]. There are also people working on quadrotors that don't cooperate/do acrobatics and who don't rely on fixed vision systems - for example people working on autonomous quadrotor mapping [5] and using IMUs and on-robot vision [6].
[1] http://www.youtube.com/watch?v=MvRTALJp8DM
[2] http://www.youtube.com/watch?v=wuSqwb13iw0
[3] http://www.youtube.com/watch?v=uoiJeIb0wBA
[4] http://www.youtube.com/watch?v=cXSGTkI390w
[5] http://www.youtube.com/watch?v=WoMrPKCpWXw
[6] http://www.youtube.com/watch?v=QKGZcTFambE