Real-time micro-vibration testing based on digital holographic interferometry

An experimental system based on digital holographic interferometry is proposed for real-time high-precision micro-vibration measurement. Vibration information can be extracted directly and instantaneously from the hologram by using fast micro-vibration testing algorithm. As the received light of the proposed system is the scattered light, the proposed system approach no assumptions on object surface feature and receiving angles. The feasibility of the proposed system is demonstrated by using a vibrating object driven by standard sinusoidal signals. The result demonstrates that the measured amplitude can be output in real time (the processed time is about 0.11 ms). It also reveals that the measured amplitude from 550 to 2700 Hz is steady, with an output difference of 1.66%. The proposed system provides an effective way to quantitatively analyze the amplitude of micro-vibration.