Remember that scene from the Dark Knight where Batman uses sonar to find the bad guys in a building? Yeah, you might be able to do that soon with the help of your smartphone. If you are not a movie buff (do yourself a favour and at least watch the Batman trilogy) you might still know how animals such as dolphins and bats use echolocation to find their way around. These animals don’t rely on sonar rather than vision. By emitting a sound and listening to the echo, they can create accurate maps of their environment in their brains.
Researchers from the Ecole Polytechnique Federale de Lausanne, Switzerland have demonstrated a computer algorithm which would give humans the ability to map their surroundings in the near future. With the help of this technology we would be able to produce more accurate sound experiences in virtual spaces, fine tune the acoustics of architectural designs and recreate structures by using solely audio files.
Using the same technology it would be possible to locate a person via an echolocation app on their smartphone. The accuracy of the echolocation app would be down to the very room the person occupies as every room has a unique audio signature. You can imagine it as a hyper-localized audio GPS.
Technically it is a little more complex than just recording echoes, the important thing is to distinguish among them and process the strong, early reflections. To filter these echoes from the noisy, weak and confusing later reverberations the team has written an echo sorting algorithm. This algorithm discriminates between the first and later echoes and then the system creates 3D visualizations using the ‘first order’ echoes.
The next step for the team from EPFL is to build an app for phones that would use inaudible ultrasound to construct maps of the insides of buildings and people can use them to know where they are inside the building. This would require multiple phones all connected through Bluetooth of Wi-Fi in the same building.
The team lead Ivan Dokmanic is of the opinion that no less than four microphones would be needed to make sure that first order echoes are caught accurately and without fail and the noise is ignored. As an example he suggested that perhaps stores of the likes of Wal-Mart might run this and permit customers to download the echolocation app when they come in.
Dokmanic, who is currently on secondment to Microsoft Research in Redmond, Washington, is confident that the proposed indoor localization app should be launched in less than a year’s time.