Feature Tracking

The Vernier Video Physics app provides useful implementation of feature tracking technology in a mobile platform. 

Example

I recorded a video of the tip of a steel cantilever beam and used the Video Physics app to select the top corner of the beam for feature tracking. The app produces position versus time plots and the physical scale of a pixel can even be set to improve the accuracy of the position values. I measured 11 cycles taking 4 seconds, which yields a period of 0.3636 seconds, or a natural frequency of 2.75 Hz. 

If you are willing to use a computer in addition to your phone, you can record video and then do wonderful feature tracking analysis with the Tracker Video Analysis and Modelling Tool.

References

https://apps.apple.com/us/app/vernier-video-physics/id389784247 

https://www.vernier.com/product/video-physics-for-ios/ 

https://physlets.org/tracker/