While it might appear that large structures, such as bridges and buildings, remain entirely unmoved by everyday forces like rain and wind, the truth is that they do experience very slight vibrations, too small to be seen by the human eye. Those vibrations can be indicative of structural damage or instability, but current methods of detecting them are impractical and costly. A new technique developed by MIT researchers is designed to spot those telltale signs of weakness using high speed video and a computer vision technique.