CN110376213B - Optical detection system and method - Google Patents
Optical detection system and method Download PDFInfo
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- CN110376213B CN110376213B CN201910747399.2A CN201910747399A CN110376213B CN 110376213 B CN110376213 B CN 110376213B CN 201910747399 A CN201910747399 A CN 201910747399A CN 110376213 B CN110376213 B CN 110376213B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/21—Polarisation-affecting properties
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/55—Specular reflectivity
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/93—Detection standards; Calibrating baseline adjustment, drift correction
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/21—Polarisation-affecting properties
- G01N2021/216—Polarisation-affecting properties using circular polarised light
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Abstract
The invention relates to the technical field of optics, and discloses an optical detection system and method for rapidly completing the defect detection of the surface of an object. The system of the invention comprises: a multi-spectral light source; the deflection device is positioned between the multispectral light source and the object to be detected and is used for respectively deflecting the light beams with different wavelengths emitted from the multispectral light source to the direction corresponding to the wavelength and emitting the deflected light beams with different wavelengths to the object to be detected; and the data processing device is used for receiving the light beam reflected by the surface of the object to be measured, comparing the reflected spectrum with the reference calibration spectrum reflected by the corresponding standard component to determine the wavelength of the difference, and further calculating the space coordinate corresponding to the surface defect of the object to be measured according to the wavelength of the difference.
Description
Technical Field
The invention relates to the technical field of optics, in particular to an optical detection system and method.
Background
With the development of modern industrial technology, the requirement on high-precision processing technology is higher and higher, and meanwhile, surface detection also becomes an essential link for industrial development, which reflects the industrial development level of a country to a certain extent.
The surface detection is generally to detect the type, property, quantity, shape, position, size, distribution and changes of the surface defects (or foreign matters) of the tested piece by using the abnormal structure or the defects of the material surface or the changes of the reactions of heat, sound, light, electricity, magnetism and the like caused by the foreign matters and by using a physical or chemical method as a means and by means of modern technologies and equipment.
In the traditional optical surface defect detection, a scattered energy analysis method, a Fourier spectrum analysis method, a two-beam interference method, a filtering imaging method and the like are mostly adopted, and the methods have respective limitations. For example, the scattered energy analysis method has a complex system, slow detection speed and can not determine the specific position of the defect; the frequency spectrum analysis method is greatly influenced by the deep structure of the defect and cannot reflect the area of the surface layer of the defect; the interference fringes of the double-beam interference method are easy to drift and are not suitable for detecting various defects; the filtering imaging method aims at imaging of high-frequency components or low-frequency components in a light beam space spectrum and is greatly interfered by noise.
Disclosure of Invention
The invention aims to disclose an optical detection system and method for rapidly completing the defect detection of the surface of an object.
To achieve the above object, the present invention discloses an optical inspection system, comprising:
a multi-spectral light source;
the deflection device is positioned between the multispectral light source and the object to be detected and is used for respectively deflecting the light beams with different wavelengths emitted from the multispectral light source to the direction corresponding to the wavelength and emitting the deflected light beams with different wavelengths to the object to be detected;
and the data processing device is used for receiving the light beam reflected by the surface of the object to be measured, comparing the reflected spectrum with the reference calibration spectrum reflected by the corresponding standard component to determine the wavelength of the difference, and further calculating the space coordinate corresponding to the surface defect of the object to be measured according to the wavelength of the difference.
To achieve the above object, the present invention discloses a corresponding optical detection method, comprising:
setting a multispectral light source, and setting a deflection device between the multispectral light source and an object to be detected;
the spectral deflection device deflects the light beams with different wavelengths emitted from the multispectral light source to the direction corresponding to the wavelength respectively, and emits the deflected light beams with different wavelengths to the object to be detected;
and receiving the light beam reflected by the surface of the object to be measured, comparing the spectrum difference of the reflected spectrum with the reference calibration spectrum reflected by the corresponding standard component, determining the wavelength of the difference, and calculating the space coordinate corresponding to the surface defect of the object to be measured according to the wavelength of the difference.
The invention has the following beneficial effects:
the defect detection on the surface of the object can be completed quickly and accurately, and the method is simple in deployment, convenient to operate and very strong in practicability.
The present invention will be described in further detail below with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic diagram of an optical inspection system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an optical inspection system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of an optical inspection system according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a polarization grating according to an embodiment of the present invention, which has different deflection angles corresponding to different wavelengths;
fig. 5 is a schematic diagram of a spectral distribution caused by a surface defect of an object to be measured according to an embodiment of the disclosure.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways as defined and covered by the claims.
Example one
The present embodiment discloses an optical inspection system, including: multispectral light source, deflection device and data processing device.
The deflection device is positioned between the multispectral light source and the object to be measured, and is used for respectively deflecting light beams with different wavelengths emitted from the multispectral light source to the direction corresponding to the wavelength, and emitting the deflected light beams with different wavelengths to the object to be measured.
In this embodiment, the data processing apparatus is configured to: and receiving the light beam reflected by the surface of the object to be measured, comparing the spectrum difference of the reflected spectrum with the reference calibration spectrum reflected by the corresponding standard component, determining the wavelength of the difference, and calculating the space coordinate corresponding to the surface defect of the object to be measured according to the wavelength of the difference.
Generally, the light emitted from the multispectral light source is natural light. Optionally, the deflecting device of this embodiment includes a polarization grating for deflecting natural light into left-handed circularly polarized light and right-handed circularly polarized light with opposite deflecting angles, and the corresponding data processing device is provided with two sets of parallel spectrum obtaining assemblies respectively corresponding to the object to be measured and the standard component; when the left-handed circularly polarized light corresponds to the object to be detected, the right-handed circularly polarized light corresponds to the standard component; or when the right-handed circularly polarized light corresponds to the object to be detected, the left-handed circularly polarized light corresponds to the standard component.
As shown in fig. 1, the system of the present embodiment includes: multispectral light source 1, polarization grating 2 and first receiver 5, second receiver 6. The light emitted by the multispectral light source 1 is mixed natural light containing multispectral components, is deflected after passing through the polarization grating 2, and is divided into two light beams of which the ratio is 1:1, wherein one light beam is used as reference calibration light, and the other light beam is used as detection light. Similarly, the deflection angles of the two beams of light after being emitted through the polarization grating 2 have a certain corresponding relation with the wavelength lambda, and the surface defect position of the object to be detected can be detected by comparing the spectral difference of the two beams of light after being reflected by the standard part 3 and the object to be detected 4.
It is worth mentioning that: in the description of the present embodiment, for the sake of clarity, the system components in the drawings are defined by "first" and "second" before their common names for distinction, and the definitions are only for convenience of description, and are not repeated in the following.
Optionally, the deflecting device of this embodiment may include: a linear polarizer, an 1/4 wave plate, and a first polarization grating. Wherein a linear polarizer is disposed adjacent to the multispectral light source, and an 1/4 wave plate is positioned between the linear polarizer and the first polarization grating; the first polarization grating is positioned between the 1/4 wave plate and the object to be detected and is used for respectively deflecting the circularly polarized light with different wavelengths which is incident in the left rotation or the right rotation into the circularly polarized light which is emergent in the right rotation or the left rotation direction.
As shown in fig. 2, the simplified system corresponding to the above modification includes the multispectral light source 1, the linear polarizer 7, the 1/4 wave plate 8, the polarization grating 2, and the first receiver 5. The polarization direction of the linear polarizer 7 is at an angle of 45 degrees with the fast axis direction of the 1/4 wave plate 8. The light emitted by the multispectral light source 1 is mixed light containing multispectral components, and the mixed light beam is changed into circularly polarized light after passing through the linear polarizer 7 and the 1/4 wave plate 8. The circularly polarized light is deflected by the polarization grating 2 and then incident on the reflector 3. The reflector 3 may be a standard or an object to be measured. When the reflector 3 is a standard, the first receiver 5 receives the light reflected from the reflector 3, obtains a reference spectrum, and records it in the system; when the reflector 3 is switched to be the object to be measured, the first receiver 5 receives the light reflected from the reflector 3 to obtain the reflection spectrum of the object to be measured, and then the reflection spectrum is compared with the reference spectrum recorded by the system to obtain the position of the surface defect of the object.
In order to obtain the detection result in a more real-time synchronous comparison manner, preferably, the deflecting device of this embodiment further includes:
and the beam splitter is arranged at the position sharing the same linear polarizer and the 1/4 wave plate and is used for splitting a light beam into two parts to respectively correspond to the object to be measured and the standard component. And the second polarization grating is positioned between the 1/4 wave plate and the standard component and is used for respectively deflecting the circularly polarized light with different wavelengths incident in the left rotation or the right rotation into circularly polarized light emergent in the right rotation or the left rotation direction.
As shown in fig. 3, the optimized system comprises a multispectral light source 1, a light splitting device 9, a linear polarizer 7, an 1/4 wave plate 8, a first polarization grating 2, a second polarization grating 2, a first receiver 5 and a second receiver 6. Reference numerals 3 and 4 are a standard member and an object to be measured, respectively. The light emitted from the light source 1 is a mixed light of multispectral components, and the mixed light beam is split into two light beams determining a splitting ratio by the light splitting device 9. One of which is used as reference calibration light and the other as detection light. The polarization direction of the linear polarizer 7 is at an angle of 45 degrees with the fast axis direction of the 1/4 wave plate 8. The two lights pass through the linear polarizer 7 and the 1/4 wave plate 8 in order and then become two circularly polarized lights L1 and L2. Where L1 is incident on the second polarization grating 2, it will be deflected by an angle related to the wavelength lambda as shown in figure 4. Since L1 is a multi-spectral mixed light beam, after L1 exits from the second polarization grating, the light wave components with different wavelengths have different deflection angles, and the deflection angles and λ have a certain corresponding relationship, which is recorded as: θ (λ), i.e.: dispersion occurs. The dispersed light beam irradiates the standard 3, and is reflected by the standard 3 and received by the first receiver 5. The first receiver 5 can obtain a standard spectrum S1, or a reference calibration spectrum.
Similarly, the light beam L2 is incident on the first polarization grating 2, is also deflected, and then irradiates the object 4 to be detected, and is reflected by the object 4 to be detected and then received by the second receiver 6, so that the second receiver 6 obtains another detection spectrum S2. If the light splitting device is 1:1 light splitting and the object to be measured has no surface defect, the detection spectrum S2 obtained by the second receiver 6 and the standard spectrum S1 obtained by the first receiver 5 should be consistent within an error allowable range; if there is a defect on the surface of the object to be measured, as shown in fig. 5, the detection spectrum S2 and the standard spectrum S1 will have a certain deviation at the corresponding wavelength. And obtaining the position of the defect position on the surface of the object according to the corresponding relation between the wavelength lambda and the deflection angle theta.
It is worth mentioning that: in the above scenario, the positional relationship of the first polarization grating with the light beam L2 is an equivalent alternative to the positional relationship between the second polarization grating and the light beam L1. And the first polarization grating and the second polarization grating are products with the same material and the same specification and consistent performance parameters.
Example two
Corresponding to the above embodiments, the present embodiment discloses an optical detection method, including the following steps:
and step S1, setting a multispectral light source, and setting a deflection device between the multispectral light source and the object to be detected.
And step S2, the light beams with different wavelengths emitted from the multispectral light source are respectively deflected to the direction corresponding to the wavelength by the spectrum deflection device, and the deflected light beams with different wavelengths are emitted to the object to be detected.
And step S3, receiving the light beam reflected by the surface of the object to be measured, comparing the reflected spectrum with the reference calibration spectrum reflected by the corresponding standard component to determine the wavelength of the difference, and calculating the space coordinate corresponding to the surface defect of the object to be measured according to the wavelength of the difference.
Optionally, the light emitted by the multispectral light source is natural light, the deflection device includes a polarization grating for deflecting the natural light into left-handed circularly polarized light and right-handed circularly polarized light with opposite deflection angles, and the corresponding data processing device is provided with two sets of parallel spectrum acquisition assemblies respectively corresponding to the object to be measured and the standard component; when the left-handed circularly polarized light corresponds to the object to be detected, the right-handed circularly polarized light corresponds to the standard component; or when the right-handed circularly polarized light corresponds to the object to be detected, the left-handed circularly polarized light corresponds to the standard component.
Optionally, the deflecting device of this embodiment includes: a linear polarizer disposed adjacent to the multispectral light source; 1/4 wave plate located between the linear polarizer and the first polarization grating; the first polarization grating is positioned between the 1/4 wave plate and the object to be detected and is used for respectively deflecting the circularly polarized light with different wavelengths which is incident in the left rotation or the right rotation into the circularly polarized light which is emergent in the right rotation or the left rotation direction.
Preferably, the deflection device of the present embodiment further includes: the beam splitter is arranged at the position sharing the same linear polarizer and the 1/4 wave plate and is used for splitting a light beam into two parts to respectively correspond to the object to be measured and the standard component; and the second polarization grating is positioned between the 1/4 wave plate and the standard component and is used for respectively deflecting the circularly polarized light with different wavelengths incident in the left rotation or the right rotation into circularly polarized light emergent in the right rotation or the left rotation direction.
In summary, the optical detection system and the optical detection method disclosed in the above embodiments of the present invention have the following advantages:
the defect detection on the surface of the object can be completed quickly and accurately, and the method is simple in deployment, convenient to operate and very strong in practicability.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. An optical inspection system, comprising:
a multi-spectral light source;
the deflection device is positioned between the multispectral light source and the object to be detected and is used for respectively deflecting the light beams with different wavelengths emitted from the multispectral light source to the direction corresponding to the wavelength and emitting the deflected light beams with different wavelengths to the object to be detected;
the data processing device is used for receiving the light beam reflected by the surface of the object to be measured, comparing the reflected spectrum with the spectrum difference of the reference calibration spectrum reflected by the corresponding standard component, determining the wavelength of the difference, and further calculating the space coordinate corresponding to the surface defect of the object to be measured according to the wavelength of the difference;
the multispectral light source emits light which is natural light, the deflection device comprises a polarization grating which is used for deflecting the natural light into left circularly polarized light and right circularly polarized light with opposite deflection angles, and the corresponding data processing device is provided with two sets of parallel spectrum acquisition assemblies which respectively correspond to the object to be detected and the standard component; when the left-handed circularly polarized light corresponds to the object to be detected, the right-handed circularly polarized light corresponds to the standard component; or when the right-handed circularly polarized light corresponds to the object to be detected, the left-handed circularly polarized light corresponds to the standard component.
2. An optical inspection method, comprising:
setting a multispectral light source, and setting a deflection device between the multispectral light source and an object to be detected;
the deflection device deflects the light beams with different wavelengths emitted from the multispectral light source to the direction corresponding to the wavelength respectively, and emits the deflected light beams with different wavelengths to the object to be detected;
receiving the light beam reflected by the surface of the object to be measured, carrying out spectrum difference comparison on the reflection spectrum and a reference calibration spectrum reflected by a corresponding standard component, determining the wavelength of the difference, and calculating the space coordinate corresponding to the surface defect of the object to be measured according to the wavelength of the difference;
the multispectral light source emits light which is natural light, the deflection device comprises a polarization grating which is used for deflecting the natural light into left circularly polarized light and right circularly polarized light with opposite deflection angles, and the corresponding data processing device is provided with two sets of parallel spectrum acquisition assemblies which respectively correspond to the object to be detected and the standard component; when the left-handed circularly polarized light corresponds to the object to be detected, the right-handed circularly polarized light corresponds to the standard component; or when the right-handed circularly polarized light corresponds to the object to be detected, the left-handed circularly polarized light corresponds to the standard component.
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| CN111811429B (en) * | 2020-07-14 | 2021-04-20 | 北京理工大学 | Sub-aperture splicing interference measurement method and device |
| CN114018830B (en) * | 2021-10-27 | 2024-05-28 | 北京航空航天大学 | Linear polarization direction detection method based on liquid crystal polarization grating |
| CN113946034B (en) * | 2021-11-08 | 2023-09-19 | 中国科学院光电技术研究所 | Broadband chiral spectrum analysis and large-view-field imaging system and design method |
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