Variable-resolution phase unwrapping method based on point diffraction interferometer

Abstract

The invention discloses a variable-resolution phase unwrapping method based on a point diffraction interferometer. The method comprises the following steps: generating network model training and verification data by actually acquiring by the interferometer; establishing a training / verification data set after carrying out wrapping processing, and extracting interferogram phase data by adopting a four-step phase shift method; establishing a convolutional self-encoding neural network model, inputting the training data into the model, iterating the training network for multiple times until the network is in an optimal state, and then predicting to-be-processed data acquired by the instrument; carrying out region division on a wrapped phase diagram according to the resolution before prediction,and carrying out full-width unpacking through a subsequent splicing strategy; taking the original wrapping phase as a reference, extracting data jump points to obtain a wrapping region contour, usingan initial prediction result, denoising by taking the region as a unit, and optimizing the prediction result to improve the unpacking accuracy; and splicing a plurality of groups of adjacent phase data by using an Iterative Closest Point algorithm to realize adjustable resolution. And the unpacking precision is high, the universality is strong, and the real-time processing capability is strong.

Description

technical field [0001] The invention belongs to the technical field of phase data processing in the field of laser interference precision measurement, and in particular relates to a variable resolution phase unwrapping method based on a point diffraction interferometer. Background technique [0002] During the manufacturing process of spherical / aspherical optical elements, it needs to go through multiple production process steps, including grinding stage, rough polishing stage and fine polishing stage. In the early stage of production, grinding is often used for processing, and the contour method is used for detection; while in the fine polishing stage, in order to avoid low contact measurement accuracy and easy scratches on the optical surface, interferometry is often used for measurement. This is a non-destructive testing method and the accuracy can reach submicron or even nanometer level. [0003] Point-diffraction interferometry is a typical interferometry method. The i...

AI Technical Summary

Problems solved by technology

The expansion result of this method has better continuity and smoothness, but the local error is easy to spread to the global

The current neural network-based method to achieve data unpacking processing can obtain high unpacking accuracy, but the output result of this type of method is static resolution, the versatility is not strong, and the detail resolution is low

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