Vibration Measurement Research with Stroboscopic Method in Electrical Speckle Shearing Pattern Interferometry

Electrical speckle shearing pattern interferometry (ESSPI), being an interfering measurement technology, has been used to measure harmonic vibration deviating from object plane with time-average method or stroboscopic method. Time-average is generally used in qualitative analysis of vibration for the contrast of stripes in the electrical speckle shearing interfering images rapidly decreased with the addition of stripe-levels. Stroboscopic method can be used to measure instant vibration distribution. The specific measuring method and theory of stroboscopic method in electrical speckle shearing pattern interferometry are analyzed and corresponding mathematical model is set up. The vibration measuring system based on ESSPI and stroboscopic method is designed. The experiment results with the system are shown in the paper to prove the availability of stroboscopic method and capability of system to measure vibration.