Machine vision has been at the forefront of machine learning, but now it's time for machine hearing. Admittedly not on a par with machine vision, machine hearing is making significant progress reports MIT's Technology Review. Routinely, advanced machine-listening systems utilize software to monitor upcoming equipment breakdowns, track movement, and activate cameras to record traffic accidents — all based on sound. In fact, an acoustics-based GPS system is being used in U.S. cities to detect/report gunshot locations; a sniper-fire detection system onboard an unmanned aircraft is also being developed for the U.S. Air Force.