Practical Measurements of Vibration Using the Moiré Effect

Displacement measurement is a critical issue in mechanical engineering. The moiré effect increases the accuracy of contactless measurements. We theoretically estimated the sensitivity threshold of moiré measurements using a digital camera on various objects. The estimated sensitivity threshold can be as low as a sub-pixel. We confirmed this experimentally in laboratory tests with a static image on a screen and simulated movement with non-integer and fractional amplitudes. Additionally, we provide practical examples, such as displacement measurement tests conducted in laboratories and outdoors. We took simultaneous measurements in two directions. The results can be applied in public safety, particularly for monitoring the condition of engineering structures.