Dual-wavelength phase unwrapping method capable of effectively removing phase noise

A phase noise, dual-wavelength technology, applied in the field of interferometry, can solve problems such as inapplicability, and achieve the effect of avoiding the step effect

Active Publication Date: 2018-09-04
北京盛原通达科技有限公司
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  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to overcome the shortcomings that the existing methods are not suitable for large synthetic wavelength Λ occasions, the present invention provides a dual-wavelength phase unwrapping method that can effectively remove phase noise, and the method can still work normally when the noise is large

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  • Dual-wavelength phase unwrapping method capable of effectively removing phase noise
  • Dual-wavelength phase unwrapping method capable of effectively removing phase noise
  • Dual-wavelength phase unwrapping method capable of effectively removing phase noise

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Embodiment Construction

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. The described embodiments are for a better understanding of the present invention, and are simple and intuitive descriptions. The following uses one-dimensional as an example to illustrate:

[0019] Examples, two wavelengths λ 1 =633nm, λ 2 =650nm, synthetic wavelength Λ=λ 1 lambda 2 / |λ 1 -λ 2 |=24.2μm, at this time, equivalent to the wavelength λ 1 = The noise in the wrapped phase corresponding to 633nm is amplified by 2Λ / λ 1 = 76 times. The sample to be tested is a reflective stepped sample with a step height of 2 μm (corresponding to an optical path change of 4 μm), such as figure 1 (a) shown.

[0020] A dual-wavelength phase unwrapping method capable of effectively removing phase noise, specifically comprising the following steps:

[0021] (1) Starting from the interferogram, use the arctangent function to obtain two wavelengths λ 1 , lambd...

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Abstract

The invention relates to a dual-wavelength phase unwrapping method capable of effectively removing phase noise. The method transforms the phase unwrapping problem into an optimization problem by usinga total variation principle, introduces a suitable objective function to avoid an step effect during traditional total variation denoising, and is not sensitive to the amplified noise; when an interval between the two wavelengths is small and the synthesized wavelength is large, the optical path distribution of the sample to be tested can still be obtained by correct unwrapping, so when the noiseis large, the method can still work normally.

Description

technical field [0001] The invention belongs to the technical field of interference measurement, and in particular relates to a dual-wavelength phase unwrapping method capable of effectively removing phase noise. Background technique [0002] Modern interferometry techniques usually record the interferogram with a CCD (or CMOS) camera, and complete subsequent data processing in a computer. It combines optical interference technology, optical measurement technology and digital image processing technology. Because it has the advantages of full-field measurement, no need for fluorescent markers, and nanometer precision in axial measurement, it is widely used in optical detection, semiconductor processing detection, and microscopic imaging. and biomedical imaging and other fields have been widely used. In single-wavelength off-axis interferometry, the shape distribution of the measured sample can be obtained from the phase distribution, and the phase distribution needs to use t...

Claims

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Application Information

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IPC IPC(8): G01B11/25
CPCG01B11/2441G01B11/254
Inventor 郭荣礼刘王云王凡刘蓉段存丽路绍军胡加兴胡小英
Owner 北京盛原通达科技有限公司
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