For filming training videos, television shows, movies and more, it would be useful if a camera-equipped drone could follow people as they moved through an environment while providing narration. This is possible with current drone technology, but stymied by the fact that the whirring rotors drown out dialogue, not to mention provide a safety hazard should they come too close.

Japanese telecom company DoCoMo has devised a solution. Their camera-equipped blade-free drone is simply a balloon that stays aloft by being filled with helium.

To locomote, the drone relies on tiny ultrasonic modules that vibrate to produce a minute breeze in one direction, which nudges the drone in the other direction. In this manner it can move in the X-, Y- and Z-axes. It's also quiet, allowing a mic to pick up voices.

And from a safety standpoint, should the drone come into contact with an actor's head, the worst that can happen is their hair might stand up from the static electricity.

The drones also have built-in LEDs that allow them to change color. This opens the intriguing possibility that they could be used as ambient lighting; alternatively, in a venue like a convention hall, they could change color to convey information (turning red in an emergency, for instance).

Here they are in operation:

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