Out-of plane displacement reconstruction of Carrier-wave Electronic Speckle Pattern Interferometry based on sub-pixel and Fourier transform

Modern scientific research requires higher measurement accuracy on Carrier-wave Electronic Speckle Pattern Interferometry (CESPI). It is expensive to improve measurement accuracy by improving hardware resolution. So a new out-of displacement reconstruction method of CESPI was proposed in this article. Firstly, it adopts grayscale interpolation algorithms to retreat the carrier correlation fringe figures. After the sub-pixel re-sampling processing, the fringe figures will be enlarged. Then using Fourier transform phase demodulation, homomorphic filter, phase calculation operation and displacement reconstruction, three-dimensional displacement figures with sub-pixel will be reconstructed and the corresponding measuring results will be acquired. The method is a global reconstruction method which could obtain higher precision and full court out-of plane displacement information. The experiment result shows that the method has some advantages including simple, reliable, low cost and high precision.