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Phase extraction method for phase-shifting interferometric fringe

A technology of phase-shifting interference and phase extraction, applied in the field of optical detection, can solve the problems of time-consuming and large amount of calculation, and achieve the effect of fast speed, small amount of calculation, and improving the accuracy of phase measurement.

Active Publication Date: 2012-04-25
INST OF OPTICS & ELECTRONICS - CHINESE ACAD OF SCI
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Problems solved by technology

Since this type of algorithm needs repeated iterative calculations, the amount of calculation is quite large and time-consuming.

Method used

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  • Phase extraction method for phase-shifting interferometric fringe
  • Phase extraction method for phase-shifting interferometric fringe
  • Phase extraction method for phase-shifting interferometric fringe

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Embodiment Construction

[0057] The present invention will be further described below in conjunction with accompanying drawings, but not all content of the present invention is included.

[0058] Such as figure 1 Shown, the present invention realizes steps as follows:

[0059] (1) First determine the basic phase shift algorithm. The following is an example of extending the basic four-step algorithm. The total number of phase shift steps is 5, and the phase shift step length is π / 2, that is, α is 0, π / 2, π, 3π / 2, 2π respectively.

[0060] (2) Extract five-step interference fringe figure (I 1 , I 2 , I 3 , I 4 , I 5 ).

[0061] (3) Group the interference fringe images obtained in the previous step. Here, divide (I1, I2, I3, I4) into group A, (I 2 , I 3 , I 4 , I 5 ) is divided into group B, which can be obtained from the basic four-step algorithm formula (6):

[0062]

[0063]

[0064] (4) The numerator and denominator of the above two formulas are superimposed and averaged respectiv...

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Abstract

The invention relates to a phase extraction method for a phase-shifting interferometric fringe. Phase measurement error is in sine periodic distribution, while each phase of a trigonometric function has opposite positive and negative amplitudes every pi, namely the error distribution is in revert phase. Therefore, a basic algorithm can be expanded, numerators and denominators in arc tangent formulae in multiple measurement groups are subjected to overlapping average respectively, and errors are reduced by utilizing mutual cancellation of error phase distribution. On the basis of the idea, a plurality of average compensation algorithms of different situations can be deduced. The algorithm is particularly insensitive to phase displacement errors, and the phase measurement accuracy can be remarkably improved.

Description

technical field [0001] The invention relates to a phase extraction method for a phase-shifting interference fringe pattern, which belongs to the field of optical detection. Background technique [0002] Optical interferometry is a high-precision, high-sensitivity measurement method with light wavelength as the measurement unit, and it has a very wide range of applications in optical measurement. Phase-shifting interferometry was proposed by Burning et al. in 1974. He introduced the synchronous phase detection technology in communication theory into optical interferometry, which is a major development in computer-aided interferometry testing. The principle is to introduce an orderly displacement between the phase differences of the two coherent lights of the interferometer, and when the reference optical path (or phase) changes, the position of the interference fringes also moves accordingly. In this process, a photodetector is used to sample multiple array grids of the inte...

Claims

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Application Information

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IPC IPC(8): G01B9/02G01J9/02
Inventor 赵文川吴永前吴高峰侯溪万勇建范斌
Owner INST OF OPTICS & ELECTRONICS - CHINESE ACAD OF SCI
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