New Echolocation Software Can Create A 3-D Map Of A Room Where GPS Can't

A new computer algorithm out of the École polytechnique fédérale de Lausanne (EPFL) School of Computer and Communications Sciences can create a hyper-localized 3-D map simply by measuring echoes much like a bat or dolphin does.  

"Our software can build a 3D map of a simple, convex room with a precision of a few millimeters," explains PhD student Ivan Dokmanić.

The software does not require a complicated setup, and only necessitates four microphones. What's more, the microphones don't even have to be carefully placed - they can be anywhere in the room and the software will compensate by comparing various echoes to a source signal.

"Each microphone picks up the direct sound from the source, as well as the echoes arriving from various walls," Dokmanić continues. "The algorithm then compares the signal from each microphone. The infinitesimal lags that appear in the signals are used to calculate not only the distance between the microphones, but also the distance from each microphone to the walls and the sound source."

The echolocation software does this by utilizing "Euclidean distance matrices" and analyzing how many times a certain sound signal bounced off the walls before reaching the microphone. The software has performed rather successfully in environments varying from a simple room to a complex alcove, and performance seems to go up with more microphones.

While lugging around a set of microphones isn't the most consumer-friendly set up, the team of researchers are still hoping that echolocation can provide a valid, indoor alternative to GPS, which cannot penetrate the sanctity of walls as well.

The algorithm could also be used in reverse, to design a room around acoustics.

"Architects could use this to design rooms - for example concert halls or auditoriums - based upon the specific acoustics they would like to create," Dokmanić said.

You can read the full published findings in the Proceedings of the National Academy of Sciences.