Dual-wavelength deformation measurement method and measuring instrument

Abstract

The present invention discloses a dual-wavelength deformation measurement method and a measuring instrument, which comprises the following steps: Step 1: only turning on the first laser light source, so that the object to be measured remains in its original position without displacement, and directly collecting the interference image and recording it as I λ11 Step 2: Only turn on the second laser light source, so that the object to be measured remains in its original position without displacement, and the interference image is directly collected and recorded as I λ21 Step 3: Turn on only the first laser light source to displace the object to be measured, and directly capture the interference image, which is recorded as I λ12 Step 4: Turn on only the second laser light source to displace the object to be measured, and directly capture the interference image, which is recorded as I λ22 Step 5: Calculate the interference fringe intensity distribution I of the displacement of the object to be measured based on the images collected in steps 1 to 4. Step 6: Calculate the height difference Δh caused by the displacement of the object to be measured based on the interference fringe intensity distribution I of the displacement of the object to be measured calculated in step 5. The present invention has high measurement accuracy, fast measurement speed, and a wide measurement range.

Description

Technical Field

[0001] The invention relates to a dual-wavelength deformation measurement method and a measuring instrument, belonging to the technical field of interference measurement. Background Art

[0002] Deformation measurement can be divided into contact measurement and non-contact measurement according to different detection methods. The advantage of contact measurement is high measurement accuracy. A typical application of contact measurement is the coordinate measuring machine. High-precision coordinate measurement requires point-by-point scanning of the surface of the object to be measured. The measurement speed is very slow, and since the probe needs to be in contact with the object to be measured, it will not only damage the surface of the object but also affect the measurement accuracy to a certain extent. In order to overcome the inherent shortcomings of the contact measurement method, the optical interferometry measurement method is widely used in the field of deformation measurement. It has the advantages of full-field, non-contact, high precision, and high sensitivity. At present, instruments for measuring deformation all perform measurements under single wavelength conditions. Due to the limitation of the wavelength of the laser light source itself, traditional interferometers can only measure small deformations. When encountering larger surface deformations, the application range of traditional interferometers will also be limited. Summary of the Invention

[0003] The present invention provides a dual-wavelength deformation measurement method and measuring instrument, which have high measurement accuracy and fast measurement speed. It is a non-contact measurement method and will not cause any damage to the measured object. Since it is a synthetic wavelength generated by dual wavelengths, when the difference between the two wavelengths is small, the size of the object being measured can be increased, which has the advantage of a wider measurement range.

[0004] The present invention provides a dual-wavelength deformation measurement method, wherein the method uses a dual-wavelength deformation measuring instrument for measurement;

[0005] The dual-wavelength deformation measuring instrument includes a first laser light source, a second laser light source, and a charge-coupled device. A first beam splitter prism, a first attenuator, a first reflector, a first spatial filter, a first beam expander collimator, a second reflector, a third reflector, a fourth reflector, and a second beam splitter prism are sequentially provided on the propagation path of the light emitted by the first laser light source, serving as a reference light path. A first beam splitter prism, a second attenuator, a second spatial filter, a second beam expander collimator, and a second beam splitter prism are sequentially provided on the propagation path of the light emitted by the second laser light source, serving as an object light path.

[0006] The dual-wavelength deformation measurement method comprises the following steps:

[0007] Step 1: Only the first laser light source is turned on, so that the object to be measured remains in its original position without displacement, and the interference image is directly collected by the charge coupled device and recorded as I λ11 ;

[0008] Step 2: Only turn on the second laser light source to keep the object in its original position without displacement, and directly collect the interference image through the charge coupled device and record it as I λ21 ;

[0009] Step 3: Turn on only the first laser light source to displace the object to be measured, and directly collect the interference image through the charge coupled device and record it as I λ12 ;

[0010] Step 4: Turn on only the second laser light source to displace the object to be measured, and directly collect the interference image through the charge coupled device and record it as I λ22 ;

[0011] Step 5: Calculate the interference fringe intensity distribution I of the displacement of the object to be measured based on the images collected in steps 1 to 4;

[0012] Step 6: Calculate the height difference Δh caused by the displacement of the object to be measured based on the interference fringe intensity distribution I of the displacement of the object to be measured calculated in step 5.

[0013] In one embodiment of the present invention, the first laser light source and the second laser light source are controlled by switches respectively, the wavelength of the first laser light source is λ1, and the wavelength of the second laser light source is λ2.

[0014] In one embodiment of the present invention, the λ1 is not equal to λ2.

[0015] In one embodiment of the present invention, the first laser light source is a He-Ne laser with a wavelength λ1 equal to 632.8 nm, and the second laser light source is a diode laser with a wavelength λ2 equal to 637.33 nm.

[0016] In one embodiment of the present invention, the first attenuator and the second attenuator can control the light intensities of the reference light path and the object light path respectively.

[0017] In one embodiment of the present invention, the first spatial filter includes a first objective lens and a first pinhole, the first beam expander collimator includes a first lens, the second spatial filter includes a second objective lens and a second pinhole, the second beam expander collimator includes a second lens, the first pinhole and the second pinhole are respectively located at the back focal planes of the first objective lens and the second objective lens, the first pinhole and the second pinhole are used to filter high-frequency noise, and the first lens and the second lens are used to expand and collimate the light into parallel light for emission.

[0018] In one embodiment of the present invention, a third lens is further included. The object light path is irradiated onto the object to be measured through a second beam splitter prism. The laser beam is reflected back to the second beam splitter prism through the object to be measured and interferes with the reference light. The image is formed on the charge coupled device through the third lens.

[0019] In one embodiment of the present invention, a second polarizer and a first polarizer are respectively arranged between the first attenuator and the first reflector, and between the second attenuator and the second objective lens.

[0020] In one embodiment of the present invention, the step 5 of calculating the interference fringe intensity distribution I of the displacement of the object to be measured specifically includes the following steps:

[0021] Step 1. Under the illumination of two laser light sources with different wavelengths and when the object to be measured is at different positions, the object light and the reference light interfere with each other. The intensity of the interference pattern can be expressed as:

[0022]

[0023]

[0024]

[0025]

[0026] Step 2. Subtract the interference fringe intensity distributions obtained above and obtain the light intensity difference under the condition of λ1 as I λ1 ,λ2 condition

[0027] The light intensity difference under λ2 :

[0028] I λ1 =I λ11 -I λ12 ;

[0029] I λ2 =I λ21 -I λ22 ;

[0030] Step 3. Then take the I obtained in the previous step λ1 , I λ2 Subtract, simplify the formula, and then do the interference stripe after sum-difference-product transformation

[0031] The ripple intensity distribution I is:

[0032] Therefore

[0033] Because I O1 , I R1 , I O2 , I R2 The strength difference is not big, so

[0034] again

[0035] Let Δh = h2 - h1;

[0036]

[0037] Among them, I λ11 represents the fringe intensity distribution of the object to be measured without displacement under the illumination of the first laser light source with wavelength λ1, I λ21 represents the fringe intensity distribution of the object to be measured without displacement under the illumination of the second laser light source with wavelength λ2, I λ12 represents the fringe intensity distribution after the object is displaced under the illumination of the first laser light source with wavelength λ1, I λ22 represents the fringe intensity distribution of the object to be measured after displacement under the illumination of the second laser light source with wavelength λ2, I O1 is the object light intensity distribution under the condition of wavelength λ1, I R1 is the reference light intensity distribution under the condition of wavelength λ1, I O2 is the object light intensity distribution under the condition of wavelength λ2, I R2 is the reference light intensity distribution at wavelength λ2, Represents the phase of the object to be measured at the position where no displacement occurs under the illumination of the first laser light source with wavelength λ1, Represents the phase of the object to be measured at the position where no displacement occurs under the illumination of the second laser light source with wavelength λ2, Represents the phase of the position of the object to be measured after displacement under the illumination of the first laser light source with wavelength λ1, It represents the phase of the position of the object to be measured after displacement under the illumination of the second laser light source with a wavelength of λ2, and I represents the fringe intensity distribution of the displacement of the object to be measured.

[0038] In one embodiment of the present invention, the step 6 of calculating the height difference Δh caused by the displacement of the object to be measured is specifically to simplify the interference fringe intensity distribution in step 5 by the formula of synthetic wavelength, and then shift it by Λ / 2 to obtain the height difference Δh caused by the displacement of the object to be measured;

[0039] Since sin(Δh(λ1+λ2)*π / λ1λ2) in step 5 cannot be resolved on the charge coupled device, we can:

[0040]

[0041] again

[0042]

[0043] After Δh displacement Λ / 2,

[0044] I / II=tan(Δh*π / Λ);

[0045]

[0046] Where II represents the fringe intensity distribution of the object to be measured after the object to be measured has shifted by Λ / 2, Λ represents the synthetic wavelength, and Δh refers to the height difference caused by the displacement of the object to be measured.

[0047] Beneficial effects

[0048] (1) The dual-wavelength deformation measuring instrument of the present invention switches the on-off state of the laser light source of two wavelengths to obtain a synthetic wavelength that expands the range of measurable deformation, so that the measuring instrument has the advantage of a wide measurement range.

[0049] (2) The principle of the dual-wavelength deformation measuring instrument of the present invention is based on interferometry, so it is a contactless measurement and will not cause any damage to the sample being measured. In addition, interferometry itself has the advantages of high measurement accuracy and fast measurement speed.

[0050] (3) The dual-wavelength deformation measuring instrument of the present invention divides the object light and the reference light into two beams, and places attenuators in the two optical paths respectively, so as to achieve the effect of adjusting the light intensity of the two paths separately, which greatly improves the fringe quality of the interference pattern.

[0051] (4) The present invention has the advantages of high measurement accuracy and fast measurement speed. It is a non-contact measurement method and will not cause any damage to the measured object. Since it is a synthetic wavelength generated by dual wavelengths, when the difference between the two wavelengths is small, the measurable size of the measured object can be increased, which has the advantage of a wider measurement range. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0053] Figure 1 Schematic diagram of the structure of a dual-wavelength deformation measuring instrument according to embodiment 1 of the present invention;

[0054] Figure 2 Schematic diagram of the structure of a dual-wavelength deformation measuring instrument according to embodiment 3 of the present invention;

[0055] Figure 3 Schematic diagram of the structure of a dual-wavelength deformation measuring instrument according to embodiment 4 of the present invention;

[0056] In the figure, 1. first laser light source; 2. first beam splitter prism; 3. first attenuator; 4. first reflector; 5. first objective lens; 6. first pinhole; 7. first lens; 8. second reflector; 9. third reflector; 10. fourth reflector; 11. second beam splitter prism; 12. object to be measured before displacement; 13. object to be measured after displacement; 14. second laser light source; 15. second attenuator; 16. second objective lens; 17. second pinhole; 18. second lens; 19. third lens; 20. charge coupled device; 21. first polarizer; 22. second polarizer. DETAILED DESCRIPTION

[0057] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0058] Example 1:

[0059] like Figure 1 As shown, this embodiment discloses a dual-wavelength deformation measuring instrument, including a first laser light source 1 and a second laser light source 14. A first beam splitter prism 2, a first attenuator 3, a first reflector 4, a first spatial filter, a first beam expander collimator, a second reflector 8, a third reflector 9, a fourth reflector 10 and a second beam splitter prism 11 are sequentially provided on the propagation path of the light emitted by the first laser light source 1 as a reference light path; a first beam splitter prism 2, a second attenuator 15, a second spatial filter, a second beam expander collimator and a second beam splitter prism 11 are sequentially provided on the propagation path of the light emitted by the second laser light source 14 as an object light path.

[0060] Furthermore, the first laser light source 1 and the second laser light source 14 are respectively controlled by switches. The wavelength of the first laser light source 1 is λ1, and the wavelength of the second laser light source 14 is λ2, and λ1 is not equal to λ2. Optionally, in this embodiment, the first laser light source 1 is a He-Ne laser with a wavelength λ1 equal to 632.8 nm, and the second laser light source 14 is a diode laser with a wavelength λ2 equal to 637.33 nm.

[0061] Optionally, the first attenuator 3 and the second attenuator 15 can control the light intensities of the reference light path and the object light path respectively.

[0062] Optionally, the first spatial filter includes a first objective lens 5 and a first pinhole 6, the first beam expander collimator includes a first lens 7, the second spatial filter includes a second objective lens 16 and a second pinhole 17, the second beam expander collimator includes a second lens 18, the first pinhole 6 and the second pinhole 17 are respectively located at the back focal planes of the first objective lens 5 and the second objective lens 16. Since the pinhole itself is a low-pass filter, high-frequency noise can be filtered out, and then expanded and collimated by the first lens 7 and the second lens 18 respectively to become parallel light and emitted.

[0063] Furthermore, it also includes a third lens 19 and a charge-coupled device (CCD) 20. The object light path is irradiated on the object to be measured through the second beam splitter prism 11. The laser beam is reflected back to the second beam splitter prism 11 after passing through the object to be measured and interferes with the reference light, and is imaged on the charge-coupled device 20 through the third lens 19.

[0064] The object to be measured is placed in a fixed position, and two holograms produced by lasers of different wavelengths are measured. The object to be measured is then deformed (deformation refers to displacement of the object to be measured, where the undisplaced object to be measured is referred to as the pre-displacement object 12, and the displaced object to be measured is referred to as the post-displacement object 13). Two holograms produced by lasers of different wavelengths are again obtained. The holograms measured by the two laser wavelengths before displacement are first subtracted, and then the two holograms obtained after displacement are subtracted. Due to the high fringe density, the fringe distribution cannot be seen. Finally, the subtracted images are subtracted again to obtain the fringe image distribution of the displaced object to be measured, thereby obtaining the height difference of the displacement of the object to be measured.

[0065] Example 2:

[0066] This embodiment provides a dual-wavelength deformation measurement method, which uses the dual-wavelength deformation measuring instrument provided in Example 1 for measurement, and includes the following steps:

[0067] Step 1: Only the first laser light source 1 is turned on, so that the object to be measured remains in its original position without displacement, and the interference image is directly collected by the charge coupled device 20 and recorded as I λ11 ;

[0068] Step 2: Only the second laser light source 14 is turned on, so that the object to be measured remains in its original position without displacement, and the interference image is directly collected by the charge coupled device 20 and recorded as I λ21 ;

[0069] Step 3: Turn on only the first laser light source 1 to displace the object to be measured, and directly collect the interference image through the charge coupled device 20, which is recorded as I λ12 ;

[0070] Step 4: Turn on only the second laser light source 14 to displace the object to be measured, and directly collect the interference image through the charge coupled device 20, which is recorded as I λ22 ;

[0071] Step 5: Calculate the interference fringe intensity distribution I of the displacement of the object to be measured based on the images collected in steps 1 to 4;

[0072] Step 6: Calculate the height difference Δh caused by the displacement of the object to be measured based on the interference fringe intensity distribution I of the displacement of the object to be measured calculated in step 5.

[0073] Furthermore, the step 5 of calculating the interference fringe intensity distribution I of the displacement of the object to be measured specifically includes the following steps:

[0074] Step 1. Under the illumination of two laser light sources with different wavelengths and when the object to be measured is at different positions, the object light and the reference light interfere with each other. The intensity of the interference pattern can be expressed as:

[0075]

[0076]

[0077]

[0078]

[0079] Step 2. Subtract the interference fringe intensity distributions obtained above and obtain the light intensity difference under the condition of λ1 as I λ1 ,λ2 condition

[0080] The light intensity difference under λ1 :

[0081] I λ1 =I λ11 -I λ12 ;

[0082] I λ2 =I λ21 -I λ22 ;

[0083] Step 3. Then take the I obtained in the previous step λ1 , I λ2 Subtract, simplify the formula, and then perform sum-difference-product transformation to obtain the interference fringe intensity distribution I:

[0084] Therefore

[0085] Because I O1 , I R1 , I O2 , I R2The strength difference is not big, so

[0086] again

[0087] Let Δh = h2 - h1;

[0088]

[0089] Among them, I λ11 represents the fringe intensity distribution of the object to be measured without displacement under the illumination of the first laser light source 1 with wavelength λ1, I λ21 represents the fringe intensity distribution of the object to be measured without displacement under the illumination of the second laser light source 14 with a wavelength of λ2, I λ12 represents the fringe intensity distribution after the object is displaced under the illumination of the first laser light source 1 with a wavelength of λ1, I λ22 represents the fringe intensity distribution of the object to be measured after displacement under the illumination of the second laser light source 14 with a wavelength of λ2, I O1 is the object light intensity distribution under the condition of wavelength λ1, I R1 is the reference light intensity distribution under the condition of wavelength λ1, I O2 is the object light intensity distribution under the condition of wavelength λ2, I R2 is the reference light intensity distribution at wavelength λ2, represents the phase of the object to be measured at the position where no displacement occurs under the illumination of the first laser light source 1 with a wavelength of λ1, represents the phase of the object to be measured at the position where no displacement occurs under the illumination of the second laser light source 14 with a wavelength of λ2, represents the phase of the position of the object to be measured after displacement under the illumination of the first laser light source 1 with wavelength λ1, It represents the phase of the position of the object to be measured after displacement under the illumination of the second laser light source 14 with a wavelength of λ2, and I represents the intensity distribution of the fringe of the displacement of the object to be measured.

[0090] Furthermore, the step 6 of calculating the height difference Δh caused by the displacement of the object to be measured is specifically to simplify the interference fringe intensity distribution in step 5 by the formula of synthetic wavelength, and then to obtain the height difference Δh caused by the displacement of the object to be measured after shifting by Λ / 2;

[0091] Since sin(Δh(λ1+λ2)*π / λ1λ2) in step 5 cannot be resolved on the charge coupled device, we can:

[0092]

[0093] again

[0094]

[0095] After Δh displacement Λ / 2,

[0096] I / II=tan(Δh*π / Λ);

[0097]

[0098] Where II represents the fringe intensity distribution of the object to be measured after the object to be measured has shifted by Λ / 2, Λ represents the synthetic wavelength, and Δh refers to the height difference caused by the displacement of the object to be measured.

[0099] Example 3:

[0100] like Figure 2 As shown, this embodiment provides a second dual-wavelength deformation measuring instrument. This embodiment differs from Example 1 in the method for obtaining two laser light sources with different wavelengths. Specifically, this embodiment eliminates the second laser light source 14 of Example 1, instead emitting light of two different wavelengths through the first laser light source 1. This embodiment is characterized by obtaining light sources of different wavelengths through the use of a translator. This embodiment adds a translator to a single-wavelength light source. The translator can shift the wavelength of the laser light source, thereby obtaining a composite wavelength to increase the measurement range and enable measurement of large deformations. The dual-wavelength deformation measuring instrument provided by this embodiment can also be used to perform measurements using the dual-wavelength deformation measurement method disclosed in Example 2.

[0101] Example 4:

[0102] like Figure 3 As shown, this embodiment provides a third dual-wavelength deformation measuring instrument. The difference between this embodiment and embodiment 1 is that a second polarizer 22 and a first polarizer 21 are respectively provided between the first attenuator 3 and the first reflector 4, and between the second attenuator 15 and the second objective lens 16. The characteristic of this embodiment is that the first laser light source 1 with a wavelength of λ1 and the second laser light source 14 with a wavelength of λ2 can be turned on at the same time. Since one of the two wavelengths of laser light sources can pass through the polarizer and the other cannot, by placing appropriate polarizers, it is possible to capture images separately to achieve the measurement of the displacement of the object to be measured. The third dual-wavelength deformation measuring instrument provided in this embodiment can also be measured using the dual-wavelength deformation measurement method disclosed in embodiment 2. The advantage of this embodiment is that the two light sources can be more conveniently adjusted by placing different polarizers.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dual-wavelength deformation measurement method, characterized in that: The measurement is carried out using a dual-wavelength deformation measuring instrument; The dual-wavelength deformation measuring instrument includes a first laser light source, a second laser light source, and a charge-coupled device. A first beam splitter prism, a first attenuator, a first reflector, a first spatial filter, a first beam expander collimator, a second reflector, a third reflector, a fourth reflector, and a second beam splitter prism are sequentially provided on the propagation path of the light emitted by the first laser light source, serving as a reference light path. A first beam splitter prism, a second attenuator, a second spatial filter, a second beam expander collimator, and a second beam splitter prism are sequentially provided on the propagation path of the light emitted by the second laser light source, serving as an object light path. The dual-wavelength deformation measurement method comprises the following steps: Step 1: Only the first laser light source is turned on, so that the object to be measured remains in its original position without displacement, and the interference image is directly collected by the charge coupled device and recorded as I λ11 ; Step 2: Only turn on the second laser light source to keep the object in its original position without displacement, and directly collect the interference image through the charge coupled device and record it as I λ21 ; Step 3: Turn on only the first laser light source to displace the object to be measured, and directly collect the interference image through the charge coupled device and record it as I λ12 ; Step 4: Turn on only the second laser light source to displace the object to be measured, and directly collect the interference image through the charge coupled device and record it as I λ22 ; Step 5: Calculate the interference fringe intensity distribution I of the displacement of the object to be measured based on the images collected in steps 1 to 4; Step 6: Calculate the height difference Δh caused by the displacement of the object to be measured based on the interference fringe intensity distribution I of the displacement of the object to be measured calculated in step 5.

2. The dual-wavelength deformation measurement method according to claim 1, characterized in that: The first laser light source and the second laser light source are controlled by switches respectively. The wavelength of the first laser light source is λ1, and the wavelength of the second laser light source is λ2.

3. The dual-wavelength deformation measurement method according to claim 2, characterized in that: The λ1 is not equal to λ2.

4. The dual-wavelength deformation measurement method according to claim 1, characterized in that: The first laser light source is a He-Ne laser with a wavelength λ1 equal to 632.8 nm, and the second laser light source is a diode laser with a wavelength λ2 equal to 637.33 nm.

5. The dual-wavelength deformation measurement method according to claim 1, characterized in that: The first attenuator and the second attenuator can respectively control the light intensities of the reference light path and the object light path.

6. The dual-wavelength deformation measurement method according to claim 1, characterized in that: The first spatial filter includes a first objective lens and a first pinhole, the first beam expander collimator includes a first lens, the second spatial filter includes a second objective lens and a second pinhole, the second beam expander collimator includes a second lens, the first pinhole and the second pinhole are respectively located at the back focal planes of the first objective lens and the second objective lens, the first pinhole and the second pinhole are used to filter high-frequency noise, and the first lens and the second lens are used to expand and collimate the beam into parallel light for emission.

7. The dual-wavelength deformation measurement method according to claim 1, characterized in that: It also includes a third lens, the object light path is irradiated on the object to be measured through the second beam splitter prism, the laser beam is reflected back to the second beam splitter prism after passing through the object to be measured and interferes with the reference light, and is imaged on the charge coupled device through the third lens.

8. The dual-wavelength deformation measurement method according to claim 6, characterized in that: A second polarizer and a first polarizer are respectively arranged between the first attenuator and the first reflector, and between the second attenuator and the second objective lens.

9. The dual-wavelength deformation measurement method according to claim 1, characterized in that: The step 5 of calculating the interference fringe intensity distribution I of the displacement of the object to be measured specifically includes the following steps: Step 1. Under the illumination of two laser light sources with different wavelengths and when the object to be measured is at different positions, the object light and the reference light interfere with each other, and the intensity of the interference pattern is expressed as: Step 2. Subtract the interference fringe intensity distributions obtained above and obtain the light intensity difference under the condition of λ1 as I λ1 , the light intensity difference under λ2 is I λ2 : I λ1 =I λ11 -I λ12 ; I λ2 =I λ21 -I λ22 ; Step 3. Then take the I obtained in the previous step λ1 , I λ2 Subtract, simplify the formula, and then perform sum-difference-product transformation to obtain the interference fringe intensity distribution I: Therefore Because I O1 , I R1 , I O2 , I R2 The strength difference is not big, so again Let Δh = h2 - h1; Among them, I λ11 represents the fringe intensity distribution of the object to be measured without displacement under the illumination of the first laser light source with wavelength λ1, I λ21 represents the fringe intensity distribution of the object to be measured without displacement under the illumination of the second laser light source with wavelength λ2, I λ12 represents the fringe intensity distribution after the object is displaced under the illumination of the first laser light source with wavelength λ1, I λ22 represents the fringe intensity distribution of the object to be measured after displacement under the illumination of the second laser light source with wavelength λ2, I O1 is the object light intensity distribution under the condition of wavelength λ1, I R1 is the reference light intensity distribution under the condition of wavelength λ1, I O2 is the object light intensity distribution under the condition of wavelength λ2, I R2 is the reference light intensity distribution at wavelength λ2, Represents the phase of the object to be measured at the position where no displacement occurs under the illumination of the first laser light source with wavelength λ1, Represents the phase of the object to be measured at the position where no displacement occurs under the illumination of the second laser light source with wavelength λ2, Represents the phase of the position of the object to be measured after displacement under the illumination of the first laser light source with wavelength λ1, It represents the phase of the position of the object to be measured after displacement under the illumination of the second laser light source with a wavelength of λ2, and I represents the fringe intensity distribution of the displacement of the object to be measured.

10. The dual-wavelength deformation measurement method according to claim 9, characterized in that: The step 6 of calculating the height difference Δh caused by the displacement of the object to be measured is specifically to simplify the interference fringe intensity distribution in step 5 by the formula of synthetic wavelength, and then to obtain the height difference Δh caused by the displacement of the object to be measured after shifting by Λ / 2; Since sin(Δh(λ1+λ2)*π / λ1λ2) in step 5 cannot be resolved on the charge coupled device, we can: again After Δh displacement Λ / 2, I / II=tan(Δh*π / Λ); Where II represents the fringe intensity distribution of the object to be measured after the object to be measured has shifted by Λ / 2, Λ represents the synthetic wavelength, and Δh refers to the height difference caused by the displacement of the object to be measured.

Images