Image: courtesy of the researchers
The world is vibrating all over even if you can't at this very moment feel it. Yeah, it sounds like some New Age garbage, I know, yet it's more or less true. Every structure has a fundamental or natural frequency that it vibrates at in the absence of an outside force, which is just an everyday property of that particular physical system.The motion of non-motion is pretty hard to detect, however. Usually, engineers hunt out structural deformations and vibrations using lasers and accelerometers. Both of these methods are expensive and time-consuming: a single high-precision accelerometer can go for $1,000 and it takes a whole lot of them to do the job.It'd be nice to be able to monitor these movements with just a camera, which is what a recent algorithm developed by engineers at MIT offers. The technique, which is described in a recent paper published in the Journal of Sound and Vibration, takes high-speed video of a given structure and decomposes it frame by frame, assigning each one a different frequency of motion. The effect of this is to greatly exaggerate subpixel motions within a target region of pixels. The results can be seen above.As different structures have different natural frequencies, it's possible to determine if something is amiss by changes to that frequency. One application would be in pipeline monitoring, where variations might indicate a rupture or crack somewhere."This could be a noncontact sensor technology that can be used for economic and speedy applications," Oral Buyukozturk, an MIT engineering professor and lead author of the new paper, explains. "Depending on your objective, perhaps you could use the camera on your cellphone for screening, and if you detect something, you could concentrate on it with a high-power camera. There are levels of inspection, and you don't always have to start with the highest-quality camera."