Research And Application Of Phase Reconstruction Method Of Fiber Interference Fringe Pattern Based On Schmidt Orthogonalization

The 3D measuring method based on the structured-light projection of optical-fiber interference fringe has advantages in the 3D measurement for small-sized objects due to its advantages such as good sinusoidal property of the interference fringe,flexible structure and strong environmental adaptability.With the development of this technology,the higher requirements and standards are put on the volume of the measured object,the speed and accuracy of phase reconstruction algorithm in industrial applications.Therefore,in this paper,under the application background of 3D measurements for the small-sized objects,the Gram-Schmidt orthogonalization method is applied to the phase reconstruction of optical-fiber interference fringe pattern to research,and a set of 3D measurement system is developed based on this method,the main work is as follows:(1)Realizing the high-density interference fringe projection with better cosine within a small range through the fringe structured-light projection system based on the Mach-Zehnder fiber interferometer framework and Young's double-slit interference fundamental;and collecting the fringe pattern by high-speed camera at any time for related preprocessing:The Gaussian function transformation method is utilized to enhance the contrast of the darker region of the fringe pattern,and the median rotation filter is used to remove the noise without aftfecting the fringe distribution in the normal direction.(2)Utilizing Gram-Schmidt orthogonalization method to extract the phase information of the interference fringe pattern,and designing a least-square phase unwrapping algorithm based on fringe contour clipping to reconstruct the comprehensive phase of the measured object quickly and accurately.This method not only solves the phase-drift problem caused by the temperature fluctuation and environmental vibration in the interference system,but also eliminates the low zero-frequency background component by adaptive Gaussian high-pass filter,which avoids spectral aliasing problems caused by FTP.(3)Building a 3D measurement system based on the structured-light projection of the optical-fiber interference fringe,which is combined with the phase-height calibration parameters to realize the calibration of the mathematical model parameters of the system,and the measurement experiments are carried out for small-sized objects,which are compared with the results measured by FTP method.The experimental results show that the measurement system can improve the accuracy while ensuring the measurement speed,which is suitable for high-precision online 3D measurement.