Mini-displacement measurement method based on generalized phase shift digital holography

Abstract

The invention provides a mini-displacement measurement method based on generalized phase shift digital holography, and relates to the technical field of precision measurement. By use of a generalized phase shift digital holography experiment optical path and a generalized phase shift interferometry phase shift extracting algorithm, a program is compiled so an accurate algorithm of an extracted phase shift is achieved. Though realization of the algorithm, the relation between strip change and a reference light phase shift is found and an accurate phase shift value is obtained. By use of the relation expression between the phase shift value and a micro-displacement of a reflector mirror, the displacement of a micro nanoscale of movement of a target reflector mirror is calculated. According to the invention, the accuracy can reach the nanometer level; the generalized phase shift digital holography experiment optical path is quite easy to establish; and by use of the accurate algorithm of the phase shift extraction, quite easy extraction of the phase shift value is achieved.

Description

technical field [0001] The invention relates to the technical field of precision measurement, in particular to a small displacement measurement method based on generalized phase shift digital holography. Background technique [0002] The measurement of tiny displacement involves the principle of precision measurement and related technologies. Starting from the precision prediction curve, precision measurement can derive many precision measurement technologies. The precision of precision measurement has also reached the level of millimeters and microns. nanoscale. The measurement method has developed from micron-level three-coordinate measurement, surface measurement and roundness measurement technology to micro-nano measurement technology based on scanning probe microscope, optical interference microscope measurement technology and X-ray scanning interferometry technology for nanometer measurement. So far, precision measurement technology has rapidly developed into image re...

AI Technical Summary

Problems solved by technology

However, in actual operation, the combination of the moving microscope and the interferometer may cause relatively large difficulties in adjustment, and it must be ensured that the microscope is perpendicular to the moving direction of the object to be measured on the Mayers interferometer. There are high requirements on the object to be tested, and the measurement is difficult;

[0009] 3. The traditional CCD micro-displacement measurement method is to use a device similar to the CCD displacement meter. During the entire measurement process, the receiving light points obtained on the CCD are directly reflected by the surface of the measured object, so the CCD displacement meter measures the micro-displacement. The method is greatly affected by the surface of the measured object, and if the reflection effect of the measured object surface is not obvious or the shape of the measured object surface is irregular, this measurement method cannot achieve good results.

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