Vibration measurement using a low-cost imaging sensor and image processing techniques

Vibration measurement is essential for the monitoring of rotational machineries in a variety of industries. This paper presents a novel method using a low-cost imaging sensor and image processing techniques to measure the vibration of a rotor. A series of regions of interest in the captured images is selected to extract useful information for vibration measurement. Digital image correlation is applied to evaluate the similarity level of the regions of interest between sequential images and the reference image. Vibration measurement of a rotor is achieved through the spectral analysis of the signal indicating image similarity level. Experimental assessments of the proposed method were conducted on a purpose-built test rig where a commercial eddy current sensor was used to provide reference data. Experimental results demonstrate that the vibration frequencies and their relative amplitudes from the proposed measurement system agree well with those from the reference sensor. Meanwhile, the rotor vibrates at several distinct frequencies that increase with the rotational speed and hence agrees the expected vibration characteristics.