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Single black and white ccd phase shift dual wavelength interferometry method based on specific phase shift

A dual-wavelength interference and phase-shifting interference technology, which is applied in the field of single-black-and-white CCD phase-shifting dual-wavelength interferometry, can solve problems such as difficult guarantees, errors, and separation of single-wavelength interferograms, and achieve small quantities, elimination, and flexible phases. The effect of displacement selection

Inactive Publication Date: 2017-08-25
SOUTH CHINA NORMAL UNIVERSITY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there are two problems in this method. One is to use light sources close to the wavelengths of red, green, and blue. When the wavelengths of the light sources deviate from the three primary colors, or the wavelengths of the two light sources are not much different, it is difficult to ensure correct separation. Single-wavelength interferogram; second, because the interferograms of different wavelengths are not completely aligned, there will be a certain error at the edge of the object jump

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  • Single black and white ccd phase shift dual wavelength interferometry method based on specific phase shift
  • Single black and white ccd phase shift dual wavelength interferometry method based on specific phase shift
  • Single black and white ccd phase shift dual wavelength interferometry method based on specific phase shift

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Embodiment 1

[0094] In embodiment one, using figure 1 The measurement optical system and the figure 2 The flow of steps shown is carried out for experimental measurements. In the implementation, the spherical wave formed by the imaging objective lens IL is used as the objective light, and the imaging objective lens IL is a microscopic objective lens with a magnification of 25 times and a numerical aperture NA=0.40. Two laser beams with wavelengths of 532nm and 632.8nm are used in the measurement, and p=1 in formulas (2), (3) and (4). In the implementation, a two-step phase-shift algorithm is used to calculate the single-wavelength wrapping phase, so five simultaneous phase-shifted dual-wavelength interference fringe patterns are collected. Figure 3 is the collected five simultaneous phase-shifted dual-wavelength interference fringe patterns with specific phase shifts. From left to right, their phase shifts for the 532nm wavelength laser are δ 1,i =0, 2π, 2.38π, 4π, 4.76π, and the phase...

Embodiment 2

[0097] In order to further demonstrate the practicability of the method of the present invention, the second embodiment simulates an experiment in which the method of the present invention is used for three-dimensional shape measurement of a spiral phase plate. Figure 7 It is the height distribution of the spiral phase plate to be measured in this simulation experiment, and the height difference of the height jump part is 534nm.

[0098] Figure 8a to Figure 8e is the simulated dual-wavelength simultaneous phase-shift interference fringe pattern with five specific phase shifts containing the helical phase plate modulation information, where Figure 8a The phase shifts at both wavelengths of 532nm and 633nm are 0, Figure 8b with Figure 8d Indicates that at a wavelength of 532nm relative to Figure 8a The phase shifts are 2π and 4π, respectively. Figure 8c with Figure 8e Indicates that at a wavelength of 633nm relative to Figure 8a The phase shifts are 2π and 4π, res...

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Abstract

The invention discloses a single-black-and-white CCD phase-shift dual-wavelength interferometric method based on a specific phase shift amount, which includes step 1: constructing a co-path coaxial dual-wavelength interference system, and injecting lasers with two wavelengths of wavelength λ1 and λ2 into the interferometric In the system, adjust the lasers with two wavelengths to form an interferogram along the exact same path; second: adjust the parameters of a single black and white CCD to simultaneously collect two wavelengths of the interferogram; third: use a single black and white CCD to collect the dual waves generated by two wavelengths at the same time Long phase-shift interferogram; 4: From the collected dual-wavelength phase-shift interferogram, separate two sets of single-wavelength phase-shift interference signal images that eliminate the background; 5: Separate two sets of single-wavelength phase-shift interference signal images Carry out normalization processing; Sixth: Calculate the single-wavelength package phase diagram under the wavelengths λ1 and λ2, Seventh: Calculate the synthetic wavelength phase of the wavelengths λ1 and λ2, so as to obtain the surface three-dimensional topography information of the object to be measured. The method is simple and easy to implement.

Description

technical field [0001] The invention relates to the fields of optical interferometry and digital holographic measurement, in particular to a single-black-and-white CCD phase-shift dual-wavelength interferometry method based on a specific phase shift. Background technique [0002] Dual-wavelength interferometry is an optical interferometry technique in which two light sources of different wavelengths are used to record the interferogram of the same object, and after measuring the wrapping phase of the object at two single wavelengths, combined with the dual-wavelength phase The unwrapping technology obtains the synthetic wavelength and phase information, so as to truly reflect the three-dimensional shape of the object. Dual-wavelength interferometry technology makes up for the shortcomings of single-wavelength interferometry that cannot obtain correct results when the phase jump between adjacent points is greater than half the measurement wavelength, and expands the range of ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01B9/02
Inventor 吕晓旭张望平钟丽云王翰林费蕾寰
Owner SOUTH CHINA NORMAL UNIVERSITY
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