Assessing the Feasibility of the Use of Video Motion Magnification for Measuring Microdisplacements

Abstract

There are different techniques for measuring microdisplacements. The purpose of this paper was to ascertain whether a method of video motion magnification (VMM) can be used for measuring such displacements. For this, standard video devices (a digital single-lens reflex camera and a webcam) were used to record subtle movements of an object, and the results of the VMM technique were contrasted with an air-coupled ultrasonic sensing method that could achieve submicrometer accuracy. The results of the VMM technique highly correlate with those achieved using the ultrasonic sensor, showing that the former can accurately measure displacements in the range from about 5 to 40 $\mu \text{m}$ from a distance of about 1 m. The temporal characteristics of the moving object were well preserved. The VMM technique is an alternative to other modalities for measuring microdisplacements and has the advantage of being noncontact, long-range, and relatively low-cost.