Smartwatches and dedicated wrist-based activity trackers have become popular over the past few years. They’re decent at counting steps during walking and running, but they’re not very good at tracking most athletic activities. At Carnegie Mellon University researchers have developed a camera-based system that simply watches people at the gym doing exercises and automatically classifies their activities and counts the repetitions. The computer vision software recognizes repetitive motions and assumes those are exercises being performed over and over. Different exercises…