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A Phase Extraction Method Based on Complementary Error Correction for Phase-shifting Interferometry

A technology of error complementation and phase-shifting interference, which is applied in measuring devices, special data processing applications, instruments, etc., can solve problems such as cumbersome formulas, large amount of calculation, singular phase solution, etc., and achieve the effect of simple and fast calculation

Active Publication Date: 2017-04-12
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to solve (1) the existing linear phase shift error generally exists in various interference systems, which affects the phase information extraction accuracy; (2) when the existing linear error exceeds 5%, the phase extraction error increases sharply; (3) and the existing formulas are cumbersome, with a large amount of calculation, including the square root operation, which is prone to the problems of imaginary number phase solution and singular phase solution of super large error point

Method used

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  • A Phase Extraction Method Based on Complementary Error Correction for Phase-shifting Interferometry
  • A Phase Extraction Method Based on Complementary Error Correction for Phase-shifting Interferometry
  • A Phase Extraction Method Based on Complementary Error Correction for Phase-shifting Interferometry

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specific Embodiment approach 1

[0033] Specific embodiment one: a phase-shifting interferometry phase extraction method based on error complementary correction, characterized in that: a phase-shifting interferometry phase extraction method based on error complementary correction is specifically carried out according to the following steps:

[0034] Step 1. The expression form of the traditional five-frame algorithm is:

[0035]

[0036] in, is the phase to be solved, I 1 , I 2 , I 3 , I 4 , I 5 Take the light intensity of each frame sequence corresponding to the phase shift amount of -π, -π / 2, 0, π / 2, and π respectively, and obtain the phase information extracted by the traditional five-frame algorithm;

[0037] Step 2. Use the light intensity of the same frame sequence as the traditional five-frame algorithm to substitute into the constructed new five-frame algorithm to obtain the phase information extracted by the new five-frame algorithm. The constructed five-frame algorithm is in the form of;

...

specific Embodiment approach 2

[0041] Specific embodiment two: the difference between this embodiment and specific embodiment one is: the light intensity of the same frame sequence as the traditional five-frame algorithm is used in the step two, that is, the phase shift amount is -π, -π / 2, 0, When π / 2, π (the phase-shift step size is π / 2), the five-frame algorithm form constructed under any step size becomes the form described in formula (2), and the five-frame algorithm form constructed under any step size is:

[0042]

[0043] In the formula: is the phase to be solved, I 1 , I 2 , I 3 , I 4 , I 5 Respectively correspond to the light intensity of each frame sequence when the phase shift step size is β. Other steps and parameters are the same as those in Embodiment 1.

specific Embodiment approach 3

[0044] Specific embodiment three: the difference between this embodiment and specific embodiment one or two is: the phase to be solved described in the formula (3) The specific calculation process is:

[0045] The five-frame light intensity equations under any equal step size in the interference field are shown in formula (4):

[0046]

[0047] In the formula: is the phase to be solved, I is the light intensity of each frame sequence in the interference field, I 1 , I 2 , I 3 , I 4 , I 5 Respectively correspond to the light intensity of each frame sequence when the phase shift step is -2β, -β, 0, β, 2β; A is the DC component of the light intensity, B is the AC component of the light intensity, and β is the phase shift step size;

[0048] Will I 2 with I 4 , I 1 with I 5 Do difference, after trigonometric function and difference product operation, formulas (5) and (6) are respectively obtained after arrangement:

[0049] I 2 -I 4 =2B·sin(φ)·sin(β) (5)

[0050...

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Abstract

The invention relates to a phase extraction method in phase-shifting interferometry based on error complementary correction. The phase extraction method aims at overcoming the problems that: 1, current linear phase shifting errors commonly exist in various interference systems, thus influencing phase information extraction precision; 2, when the current linear errors exceed 5%, the phase extraction error is rapidly increased; 3, current formulas are tedious and large in operand, and includes involution and evolution, thus being easy to cause imaginary phase solution and strange phase solution with oversized error points. The phase extraction method is specifically performed according to the following steps of: 1, adopting a traditional five-frame algorithm which has the expressing form defined as a formula described in the description; 2, adopting light intensity which has the same frame sequence with the traditional five-frame algorithm, putting in the constructed new five-frame algorithm to obtain the phase information of the new five-frame algorithm, wherein the constructed five-frame algorithm form is defined as a formula described in the description; 3, establishing an error complementation five-frame algorithm. The phase extraction method in phase-shifting interferometry based on error complementary correction is applied to the technical field of three-dimensional shape optical detection of space objects.

Description

technical field [0001] The invention relates to a phase information extraction method in phase-shifting interferometry. Background technique [0002] With the continuous development of micro-nano processing technology, the requirements for the surface topography accuracy of components are getting higher and higher, and higher requirements are also put forward for the corresponding detection methods. Phase-shifting interferometry has become an ideal measurement method in the field of shape detection due to its advantages of high precision, high efficiency, and non-contact. (1) In phase-shifting interferometry, the phase information is obtained by processing each frame of interferogram with a phase-shifting algorithm, but linear phase-shifting errors generally exist in various interferometric systems, which affect the accuracy of phase information extraction. (2) In phase-shifting interferometry, although the traditional fixed-step phase-shifting algorithm is simple in operat...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01B11/00G06F19/00
Inventor 卢丙辉甘雨刘炳国刘国栋陈凤东庄志涛
Owner HARBIN INST OF TECH