Interferometry system error calibration method based on optical plane fringe image processing

Abstract

The invention discloses an interferometry system error calibration method based on optical plane stripe image processing. A measuring system is regarded as a whole, a group of interference fringe images of a measured object are firstly shot, then a measuring optical system is kept still, an optical plane is installed at the position of the measured object, the interference fringe images are shot,and finally errors of an actual measuring optical system are calibrated by processing the optical plane fringe images. The method is simple to operate, can calibrate and measure the error of the optical system only by shooting and processing a group of interference fringe images of the optical plane, and compensates the measurement result of the measured curved surface. The method is wide in application range and can be used for error calibration of several common interferometry systems, and the precision of the interferometry systems is improved. By adopting the method, the parameters betweenthe simulation calculation and the actual measurement optical system can be unified, so that the result of the computer simulation calculation is taken as the measurement reference, the use of a physical reference is avoided, the measurement cost is reduced, and the measurement flexibility is improved.

Description

technical field [0001] The invention belongs to the field of optical measurement, and in particular relates to a method for calibrating the error of a laser interferometric measurement system. Background technique [0002] Laser interferometry has many advantages such as high precision, high efficiency, rich information, and protection of the measured surface. It is a development direction of precision surface measurement. Since the processing error and installation error of each optical component in the laser interferometry system are always unavoidable, there is a difference between the actual measurement optical system and the theoretical calculation optical system, which is called the optical system error. The error of the optical system will not only reduce the accuracy of the interferometric system, but also cause the simulation results corresponding to the ideal surface model to be measured to be unable to be used as a measurement benchmark. Therefore, physical benchm...

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Problems solved by technology

[0003] Check the relevant literature and find some research on the error of the optical system: Zhang Jian et al. analyzed the main errors that affect the accuracy of the optical system in the calibration system in the study of the standard scatterer calibration system used to calibrate the visibility meter, and obtained the standard scatterer The transfer function of the optical system error in the volume calibration system provides a theoretical basis for improving the analysis and compensation of the system error; Sun Ting et al. proposed the analysis and calibration method of the optical system error of the high-precision star sensor; Lin Cunbao et al. The optimization of the optical grating interference system and the error of the optical system have been studied; Jin Chunshui and others invented the optical system wave aberration calibration device and the calibration method of the test error, which solves the problem that the existing optical system cannot evaluate its test error before testing the optical components Whether it meets the detection accuracy requirements and selects the appropriate phase-shifting algorithm to process the collected data; Kaushal, Sanjeev et al. invented an optical system for wafer inspection, which can perform error calibration; Zhang Song et al. studied Aiming at the compensation method of phase error in three-dimensional measurement of digital fringe projection; ItoShunji proposed the method of using wavelet transform to extract the optical system error in interference microscope; DeanF.Cornwell introduced a non-interference method to measure the optical system error. The method uses scattered light to obtain the error of the optical system

[0004] The above methods are all aimed at specific systems and specific objects. The proposed methods have limitations and cannot be directly applied to the error calibration of optical systems for measuring surface shape errors by laser interferometry.

[0005] It is obviously extremely complicated and infeasible to consider the influence of each optical element on the measurement results separately.

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