My Ph.D. thesis subject was Video-Augmented Environments, in which I looked at ways of using video input for the creation of novel human-computer interfaces. Video cameras cost little more now than keyboards and mice, and there are plenty of interesting things you can do with them, but at present it often isn't worth the programming effort. I built an architecture which allowed you to create simple 'triggering' circuits from basic components (sources, sinks, filters & sensors) using a scripting language.