CN110736756B - Lens inspection method - Google Patents
Lens inspection method Download PDFInfo
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- CN110736756B CN110736756B CN201910608712.4A CN201910608712A CN110736756B CN 110736756 B CN110736756 B CN 110736756B CN 201910608712 A CN201910608712 A CN 201910608712A CN 110736756 B CN110736756 B CN 110736756B
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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
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/958—Inspecting transparent materials or objects, e.g. windscreens
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
- G01M11/0242—Testing optical properties by measuring geometrical properties or aberrations
- G01M11/025—Testing optical properties by measuring geometrical properties or aberrations by determining the shape of the object to be tested
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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
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/958—Inspecting transparent materials or objects, e.g. windscreens
- G01N2021/9583—Lenses
Abstract
Provided is a lens inspection method using an image, which can detect defects such as streaks with sufficient accuracy in practical use. The inspection method of the lens comprises the following steps: acquiring an image of the fringe pattern through the inspection object lens; correcting distortion of the image; and taking the fringe pattern as a space carrier signal, acquiring information of phase change by a Fourier fringe analysis method, and detecting a defect part of the lens to be inspected by using the information of phase change.
Description
Technical Field
The present invention relates to a method for inspecting a lens using an image acquired by an imaging device.
Background
An inspection method of a lens using an image acquired by an imaging device has been developed (for example, patent document 1).
However, with the conventional inspection method of a lens using an image, defects such as streaks (abnormal refractive index due to fluctuation of density, composition, or the like) are difficult to detect, and there has been no development of an inspection method of a lens using an image that can detect defects such as streaks with sufficient accuracy in practical use.
Patent document 1: japanese patent laid-open No. 2015-55561
Therefore, there is a need for a method of inspecting a lens using an image that can detect defects such as streaks with sufficient accuracy in practical use.
Disclosure of Invention
The present invention addresses the problem of providing a method for inspecting a lens using an image, which can detect defects such as streaks with sufficient accuracy in practical use.
The inspection method of the lens of the present invention comprises the steps of: acquiring an image of the fringe pattern through the inspection object lens; correcting distortion of the image; and taking the fringe pattern as a space carrier signal, acquiring information of phase change by a Fourier fringe analysis method, and detecting a defect part of the lens to be inspected by using the information of phase change.
According to the present invention, since the defect portion of the inspection target lens is detected using the information of the phase change extracted by the fourier streak analysis method, defects such as streaks can be detected with sufficient accuracy in practical use.
In the method for inspecting a lens according to embodiment 1 of the present invention, in the step of acquiring an image of a stripe pattern, the image is acquired through a combination of an inspection target lens and a correction lens.
According to the present embodiment, since distortion is corrected to some extent by the correction lens, correction of distortion in an image becomes easy, and is advantageous when applying fourier streak analysis.
In the inspection method of a lens according to embodiment 2 of the present invention, the period of the stripe pattern is determined to be smaller than the minimum size of the assumed defect to be detected.
According to the present embodiment, by appropriately determining the period of the stripe pattern for a defect, the defect can be reliably detected.
In the method for inspecting a lens according to embodiment 3 of the present invention, the period of the stripe pattern is determined to correspond to at least two or more pixels in the image.
According to the present embodiment, by appropriately determining the number of pixels corresponding to the period of the stripe pattern, defects can be reliably detected. When the number of pixels corresponding to the period of the stripe pattern is less than 2, the contrast of the stripe pattern is significantly reduced. More preferably, the number of pixels corresponding to the period of the stripe pattern is determined to be 3 to 10. When the number of pixels corresponding to the period of the stripe pattern is 3 or more, the contrast is further improved. When the number of pixels corresponding to the period of the stripe pattern exceeds 10, the resolution of the camera becomes excessive and the cost becomes excessive.
In the method for inspecting a lens according to embodiment 4 of the present invention, the lens to be inspected is a cylindrical lens, and the image of the stripe pattern is collected in a state in which the longitudinal direction of the cylindrical portion is perpendicular to the longitudinal direction of the stripe pattern.
In the present embodiment, since the image of the stripe pattern is acquired in a state in which the longitudinal direction of the cylindrical portion of the cylindrical lens as the inspection object is perpendicular to the longitudinal direction of the stripe pattern, distortion of the stripe pattern due to the cylindrical lens is less likely to occur. Therefore, correction of distortion in an image becomes easy, and is advantageous when applying fourier streak analysis.
In the inspection method of a lens according to embodiment 5 of the present invention, the inspection target lens has a portion extending linearly on the surface thereof, the portion being a portion having a substantially constant cross-sectional shape perpendicular to the line and having a higher spatial frequency than surrounding portions, and an image of the stripe pattern is acquired in a state in which the longitudinal direction of the line is perpendicular to the longitudinal direction of the stripes of the stripe pattern.
In the present embodiment, when a lens having a portion extending linearly on the surface and having a portion with a cross-sectional shape substantially fixed perpendicular to the line and having a higher spatial frequency than the surrounding portion is inspected, an image of the stripe pattern is acquired in a state where the longitudinal direction of the line is perpendicular to the longitudinal direction of the stripe pattern, and therefore distortion of the stripe pattern due to the portion is less likely to occur. Therefore, correction of distortion in an image becomes easy, and is advantageous when applying fourier streak analysis. The portion of the lens having a linear shape extending on the surface thereof, having a cross-section perpendicular to the linear shape substantially fixed, and having a higher spatial frequency than the surrounding portion is, for example, a columnar ridge portion or a concave portion extending in the horizontal direction on the emission surface of the lens of the vehicle lamp, and a plurality of groove cut portions are arranged in the vertical direction.
Drawings
Fig. 1 is a diagram showing an imaging optical system used for implementing the method for inspecting defects of a lens according to the present invention.
Fig. 2 is a flowchart for explaining a method of inspecting defects of the lens of the present invention.
Fig. 3 is a flowchart for explaining a method of obtaining a position before correction and a position after correction of an image.
Fig. 4 is a view showing an image of a square grid captured through a combination of an inspection object lens and a correction lens.
Fig. 5 is a flowchart for explaining fourier streak analysis performed using the streak pattern as a spatial carrier signal in step S1030 in fig. 2.
Fig. 6 is a diagram schematically showing formula (4).
Fig. 7 is a view showing a cross section including the optical axis of a structure obtained by combining a cylindrical lens and a correction lens.
Fig. 8 is a view showing a cross section including the optical axis of a structure obtained by combining a cylindrical lens and a correction lens.
Detailed Description
Fig. 1 is a diagram showing an imaging optical system 100 used for implementing the method for inspecting defects of a lens according to the present invention. The imaging optical system 100 includes an illumination device 101, a plate 103 having a stripe pattern formed on the surface thereof, a correction lens (zero lens) 105, an inspection target lens 107, and an imaging device 109. The correction lens 105 is used to correct distortion of an image caused by the inspection object lens 107. The correction lens 105, the inspection object lens 107, and the imaging device 109 are arranged such that their centers are located on a straight line perpendicular to the surface of the plate 103 on which the stripe pattern is formed. The straight line is referred to as an optical axis, and is indicated by a one-dot chain line in fig. 1. The imaging optical system 100 is configured to collect an image of a stripe pattern of the board 103 in a direction perpendicular to the optical axis through a combination of the correction lens 105 and the inspection object lens 107. The correction lens 105 and the inspection object lens 107 may be disposed in opposite directions, that is, the convex surface of the inspection object lens 107 faces the imaging device 109.
The plate 103 having the stripe pattern formed on the surface may be a ronchi ruling (ronchi ruling). The langevice score line is formed by patterning parallel lines on the entire upper surface of a clear transparent float glass substrate, and the line width of the parallel lines is equal to the space width between the lines. As an example, the stripe pattern of the langevice score lines is a combination of 100 groups of lines and spaces between the lines in 1 inch. In this case, since 1 inch is 25.4 mm, the sum of the line width and the space width between lines, that is, the period of the stripe is 254 μm, and the line width and the space width between lines are 127 μm.
The shape of the correction lens 105 is determined so as to correct distortion of the image caused by the inspection object lens 107. A method of determining the shape of the correction lens 105 will be described later.
Here, a description will be given of a specification determination method of the imaging device 109. First, the field of view of the imaging device 109 is determined. The field of view is set to be slightly larger than the size of the plate 103. Next, the magnification of the lens of the image pickup device 109 is determined according to the size of the field of view of the image pickup device 109 and the size of the sensor of the image pickup device 109. The size of the inspection target portion corresponding to 1 pixel of the sensor is obtained from the magnification and the number of pixels of the sensor. In general, a sensor having a minimum size of a defect to be inspected of about 10 pixels or more is selected.
The number of pixels of the imaging device 109 actually used is 500 ten thousand pixels. The unit size (pixel size) was 3.45 μm×3.45 μm, and the magnification of the lens was 1. The linewidth of the langevice lines corresponds to about 3.7 pixels and the period of the langevice lines corresponds to about 7.4 pixels. In this case, 10 pixels corresponds to approximately 35 micrometers.
In general, the period of the streak, that is, the period of the langevice score line is determined so as to be smaller than the minimum size of the defect to be inspected. The number of pixels is determined so that the period of the stripe corresponds to at least two or more pixels. When the number of pixels corresponding to the period of the stripe pattern is less than 2, the contrast of the stripe pattern is significantly reduced. More preferably, the number of pixels corresponding to the period of the stripe pattern is determined to be 3 to 10. When the number of pixels corresponding to the period of the stripe pattern is 3 or more, the contrast is further improved. When the number of pixels corresponding to the period of the stripe pattern exceeds 10, the resolution of the camera becomes excessive and the cost becomes excessive.
Fig. 2 is a flowchart for explaining a method of inspecting defects of the lens of the present invention.
In step S1010 of fig. 2, an image of a stripe pattern (an image for inspection) is acquired through a combination of an inspection object lens and a correction lens. Since distortion of an image cannot be completely corrected by the correction lens, the image captured through the combination of the inspection object lens and the correction lens still has distortion. In addition, when the refractive power of the inspection object lens is small, the image of the stripe pattern may be acquired only through the inspection lens without using the correction lens.
In step S1020 in fig. 2, distortion of an image (an inspection image) is corrected. In general, a correction program (for example, openCV library or the like) that corrects distortion of an image may be used. Such a correction program moves luminance information at a position before correction to a position after correction in an image to reconstruct the image. That is, the distortion of the image can be corrected by giving the position before correction and the position after correction of the image as inputs to the correction program.
Fig. 3 is a flowchart for explaining a method of obtaining a position before correction and a position after correction of an image.
In step S2010 of fig. 3, a correction lens that corrects distortion caused by the inspection object lens as much as possible is designed. When designing the correction lens, as an example, an image obtained by capturing a pattern of a square grid of a predetermined length through a combination of the inspection object lens and the correction lens is obtained by optical simulation by a ray tracing method, and the shape of the correction lens is corrected and designed so that distortion of the image is reduced as much as possible while observing the distortion state of the square grid in the image.
In step S2020 in fig. 3, an image (correction image) obtained by capturing a square grid pattern having a predetermined length on one side is obtained by combining the lens to be inspected and the correction lens designed as described above, for example, by optical simulation.
Fig. 4 is a view showing an image of a square grid captured through a combination of an inspection object lens and a correction lens. Fig. 4 is a broken line showing an image obtained by distorting a square grid captured through a combination of an inspection object lens and a correction lens. The solid line of fig. 4 shows the shape after correction of the distortion of the square grid.
In step S2030 of fig. 3, grid points of the distorted square grid shown by a broken line in fig. 4 and grid points of the square grid shown by a solid line in fig. 4 are set as a position before correction and a position after correction of the image, respectively. As described above, by giving the position before correction and the position after correction of the image thus obtained as inputs to the correction program, the distortion of the image can be corrected.
That is, the correction procedure is adjusted to: correcting the distortion of the correction image obtained by the optical simulation in step S2020
In step S1030 of fig. 2, the information of the phase change is obtained by fourier streak analysis using the streak pattern as the spatial carrier signal, and the defect portion of the inspection target lens is detected using the information of the phase change.
Fig. 5 is a flowchart for explaining a fourier streak analysis method performed using a streak pattern as a spatial carrier signal in step S1030 in fig. 2. Although two-dimensional image processing is actually performed, in fig. 5, description is made as one-dimensional image processing for simplicity.
In addition, details of Fourier streak analysis are described in Mitsuo Takeda et al, "Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry," J.Opt.Soc.Am./Vol.72, no.1/January 1982. Further, the explanation of the Fourier streak analysis method is described in the website of the national university legal electric communication university (https:// www.uec.ac.jp/research/information/column/09. Html). The following description of steps S3010 to S3030 in fig. 5 is made by referring to a part of the description of the website.
In step S3010 in fig. 5, the intensity distribution G (x) of the light of the acquired image is fourier-transformed to obtain G (f).
Here, g (x) is represented by the following formula.
[ math 1 ]
g(x)＝a(x)+b(x)cos[2πf 0 x+φ(x)] (1)
Here, a (x) represents the intensity distribution of the background, and b (x) represents the amplitude of the light-dark variation of the stripe. f (f) 0 Is the spatial frequency of the fringes. Phi (X) is a phase having information on physical quantities such as the shape and refractive index of the lens to be inspected. When the physical quantity such as the shape and refractive index of the inspection object lens is changed from the surrounding, the phase Φ (X) is changed.
Since the following is true,
[ formula 2 ]
Therefore, the formula (1) can be rewritten as follows.
[ formula 3 ]
Here, if provided with
[ math figure 4 ]
[ formula 5 ]
The following formula (3) is obtained.
[ formula 6 ]
g(x)＝a(x)+c(x)exp(i2πf 0 x)+c * (x)exp(-i2πf 0 x) (3)
Here, information on physical quantities such as the shape and refractive index of the lens to be inspected is included in c (x) and c ＊ (x) Is a kind of medium.
Since the fourier transform of g (x) is,
[ formula 7 ]
Therefore, the following equation (4) is obtained by fourier transforming equation (3).
[ math figure 8 ]
[ formula 9 ]
[ math.10 ]
＝A(f)+C(f-f 0 )+C * [-(f+f 0 )](4)
The 1 st term of formula (4) is the Fourier spectrum of the 1 st term a (x) of formula (3), and the 2 nd and 3 rd terms of formula (4) represent c (x) and c of formula (2) * (x) Is shifted by f 0 。
Fig. 6 is a diagram schematically showing formula (4).
In step S3020 in fig. 5, the spatial carrier frequency f of G (f) is obtained 0 The nearby component C (f-f) 0 )。
In step S3030 in fig. 5, C (f-f 0 ) C (f) is obtained by moving to the origin, and C (x) is obtained by performing inverse fourier transform on C (f). Here, C (f-f 0 ) The movement to the origin corresponds to the removal of the spatial carrier frequency.
In step S3040 in fig. 5, it is determined whether c (x) at the position x is larger than a predetermined value. Since the phase Φ (X) changes when the physical quantity such as the shape and refractive index of the inspection object lens changes from the surrounding, c (X) is considered to be larger. Therefore, by determining whether c (x) at the position x is larger than a predetermined value, it can be determined whether or not there is a defect at the position x. The predetermined value is obtained as follows: an average value of c (x) of a plurality of lenses without defects is obtained, and the value is multiplied by a predetermined coefficient, for example, 1.2 or 1.5. If c (x) at the position x is greater than the predetermined value, the process proceeds to step S3050. If c (x) at the position x is equal to or smaller than the predetermined value, the process proceeds to step S3060.
In step S3050 of fig. 5, it is determined that there is a defect at the position x.
In step S3060 of fig. 5, it is determined that there is no defect at the position x.
In step S3070 in fig. 5, it is determined whether the process for all x is ended. If the processing for all x ends, the entire processing ends. If the processing for all x is not ended, the flow returns to step S3040 to perform processing for other x.
In practice, the processing shown in the flowchart of fig. 5 is performed on the two-dimensional light intensity distribution g (x, y). The two-dimensional discrete fourier transform formula of the two-dimensional light intensity distribution g (x, y) is as follows.
[ formula 11 ]
Here, u and v denote frequency spaces corresponding to x and y, respectively.
Further, the two-dimensional inverse discrete fourier transform formula of C (u, v) is as follows.
[ formula 12 ]
According to the fourier streak analysis method performed using the streak pattern as the spatial carrier signal as described above, a change in physical quantity such as the shape and refractive index of the inspection object lens can be detected as a change in the magnitude of c (x, y).
As described above, the spatial frequency of the stripe pattern, that is, the period of the stripe, needs to be equal to or smaller than the size of the minimum defect to be detected. For example, as described above, if the period of the stripes is 254 microns, the detectable defect size is greater than 254 microns.
Here, a relationship between the direction of the stripes of the stripe pattern and the orientation of the lens is studied. The distortion of the image is corrected by the correction lens and the processing of step S2010 of fig. 3 as described above. However, distortion of the image cannot be completely corrected. In fourier streak analysis, it is desirable that the pattern of streaks of the acquired image be as undistorted as possible.
Fig. 7 is a view showing a cross section including the optical axis of a structure obtained by combining the cylindrical lens 107A and the correction lens 105A. In fig. 7, stripes arranged in a stripe pattern are parallel to the longitudinal direction of the cylindrical lens 107A. Since distortion of the image acquired through the correction lens 105A and the cylindrical lens 107A cannot be corrected, a stripe pattern in the image is distorted.
Fig. 8 is a view showing a cross section including the optical axis of a structure obtained by combining the cylindrical lens 107A and the correction lens 105A. In fig. 8, stripes arranged in a stripe pattern are perpendicular to the longitudinal direction of the cylindrical lens 107A. The stripe pattern in the image stretches in the long-side direction without distortion.
Therefore, in the case where the inspection object lens is a cylindrical lens, the stripes arranged in a stripe pattern are preferably perpendicular to the longitudinal direction of the cylindrical lens.
In addition, in a lens of a vehicle lamp, a portion called a groove cut portion may be provided on an emission surface of the lens so as to diffuse a part of light irradiated near a cut-off line. The groove cutting portion is a cylindrical raised strip portion or a recessed strip portion extending in the horizontal direction, and a plurality of groove cutting portions are arranged in the vertical direction. Since the groove cut portion is cylindrical, when the inspection object lens is a lens having such a groove cut portion, the stripes arranged in a stripe pattern are preferably perpendicular to the extending direction of the groove cut portion for the same reason as when the inspection object lens is a cylindrical lens.
Claims (4)
1. A method of inspecting a lens, the method comprising the steps of:
acquiring an image of the fringe pattern through the inspection object lens;
correcting distortion of the image by using a correction program of optical simulation; and
the fringe pattern is used as a spatial carrier signal, phase change information is obtained by a fourier fringe analysis method, and the defective portion of the inspection target lens is detected using the phase change information.
2. The method for inspecting a lens according to claim 1, wherein,
in the step of acquiring an image of the fringe pattern, the image is acquired through a combination of the inspection object lens and the correction lens.
3. The method for inspecting a lens according to claim 1 or 2, wherein,
the period of the stripe pattern is determined to be smaller than the minimum size of the assumed defect as the detection object.
4. The method for inspecting a lens according to claim 1 or 2, wherein,
the period of the fringe pattern is determined to correspond to more than two pixels in the image.
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| JP2018135101A JP6539812B1 (en) | 2018-07-18 | 2018-07-18 | Inspection method of lens |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3981562A (en) * | 1974-09-09 | 1976-09-21 | Optical Coating Laboratory, Inc. | Spatial filtering for error detection |
| US6201600B1 (en) * | 1997-12-19 | 2001-03-13 | Northrop Grumman Corporation | Method and apparatus for the automatic inspection of optically transmissive objects having a lens portion |
| JP2002202112A (en) * | 2000-11-06 | 2002-07-19 | Fujitsu Ltd | Shape measuring apparatus |
| JP2008135745A (en) * | 2007-11-22 | 2008-06-12 | Nikon Corp | Wave front aberration measuring device and projection aligner |
| CN101384888A (en) * | 2006-02-16 | 2009-03-11 | Onera（法国宇航院） | Wavefront analysis method involving multilateral interferometry with frequency difference |
| CN102169095A (en) * | 2009-09-24 | 2011-08-31 | 凯德易株式会社 | Inspecting system and inspecting method |
| JP2015055561A (en) * | 2013-09-12 | 2015-03-23 | 株式会社クラレ | Defect inspection method and defect inspection device of microlens array |
| CN106707448A (en) * | 2016-11-28 | 2017-05-24 | 歌尔科技有限公司 | Adjustment system, adjustment method and display module for assembling lens |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5139869B2 (en) * | 1973-04-18 | 1976-10-30 | ||
| JP3417738B2 (en) * | 1995-09-06 | 2003-06-16 | ペンタックス株式会社 | Optical member inspection device |
| JP3613906B2 (en) * | 1996-09-20 | 2005-01-26 | 株式会社ニコン | Wavefront aberration measuring device |
| US6771362B2 (en) * | 2001-12-27 | 2004-08-03 | Rotlex Ltd. | Method and apparatus for testing and mapping phase objects |
| JP2008076223A (en) * | 2006-09-21 | 2008-04-03 | Matsushita Electric Ind Co Ltd | Inspection method of cylindrical transparent body, and inspection apparatus used for it |
| EP2063260A1 (en) * | 2007-11-19 | 2009-05-27 | Lambda-X | Fourier transform deflectometry system and method |
-
2018
- 2018-07-18 JP JP2018135101A patent/JP6539812B1/en active Active
-
2019
- 2019-07-08 CN CN201910608712.4A patent/CN110736756B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3981562A (en) * | 1974-09-09 | 1976-09-21 | Optical Coating Laboratory, Inc. | Spatial filtering for error detection |
| US6201600B1 (en) * | 1997-12-19 | 2001-03-13 | Northrop Grumman Corporation | Method and apparatus for the automatic inspection of optically transmissive objects having a lens portion |
| JP2002202112A (en) * | 2000-11-06 | 2002-07-19 | Fujitsu Ltd | Shape measuring apparatus |
| CN101384888A (en) * | 2006-02-16 | 2009-03-11 | Onera（法国宇航院） | Wavefront analysis method involving multilateral interferometry with frequency difference |
| JP2008135745A (en) * | 2007-11-22 | 2008-06-12 | Nikon Corp | Wave front aberration measuring device and projection aligner |
| CN102169095A (en) * | 2009-09-24 | 2011-08-31 | 凯德易株式会社 | Inspecting system and inspecting method |
| JP2015055561A (en) * | 2013-09-12 | 2015-03-23 | 株式会社クラレ | Defect inspection method and defect inspection device of microlens array |
| CN106707448A (en) * | 2016-11-28 | 2017-05-24 | 歌尔科技有限公司 | Adjustment system, adjustment method and display module for assembling lens |
Non-Patent Citations (1)
| Title |
|---|
| An Algorithm Based on PFT for Defect Recognition of X-ray Steel Rope Cord Conveyer Belt Image;Houpeng Liu et.al;《Advanced Materials Research》;第722卷;572-575 * |
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| CN110736756A (en) | 2020-01-31 |
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