If you've been to college or university, you'll know the feeling: when your professor drones on for hours on end, but you're hesitant to bring it up out of politeness (or fear of said professor's wrath). You won't have to be quite so shy in Wei Xiaoyong's science classes, though. The Sichuan University educator is using a custom-built facial recognition system to scan students' faces and determine whether or not they're bored. The approach gauges the emotion in your face over time, helping Wei refine his lectures so that he doesn't lose your interest.
It's not guaranteed to be completely effective, of course (what if you're particularly stoic?), and it's easy to see students being nervous about the privacy ramifications of scanning faces. Wei is sharing his approach with other Chinese universities, however, which suggests that it's successful enough. And the underlying tech isn't limited to the classroom -- Wei sees it applying to psychology, social sciences and anywhere else where measuring emotional changes could be useful.