Three-dimensional deep sub-wavelength defect detection using λ = 193 nm optical microscopy

The computer-vision-based surface defect detection of metal planar materials is a research hotspot in the field of metallurgical industry. The high standard of planar surface quality in the metal manufacturing industry requires that the performance of an automated visual inspection system and its algorithms are constantly improved. This paper attempts to present a comprehensive survey on both two-dimensional and three-dimensional surface defect detection technologies based on reviewing over 160 publications for some typical metal planar material products of steel, aluminum, copper plates and strips. According to the algorithm properties as well as the image features, the existing two-dimensional methodologies are categorized into four groups: statistical, spectral, model, and machine learning-based methods. On the basis of three-dimensional data acquisition, the three-dimensional technologies are divided into stereoscopic vision, photometric stereo, laser scanner, and structured light measurement methods. These classical algorithms and emerging methods are introduced, analyzed, and compared in this review. Finally, the remaining challenges and future research trends of visual defect detection are discussed and forecasted at an abstract level.

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Feasibility demonstration of a massively parallelizable optical near-field sensor for sub-wavelength defect detection and imaging

Scientific Reports ◽

10.1038/srep26172 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 1

Author(s):

Mahkamehossadat Mostafavi ◽

Rodolfo E. Diaz

Keyword(s):

Defect Detection ◽

Near Field ◽

Field Sensor ◽

Sub Wavelength

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Optics, Optical Methods, and Microscopy

Principles of Materials Characterization and Metrology ◽

10.1093/oso/9780198830252.003.0006 ◽

2021 ◽

pp. 345-407

Author(s):

Kannan M. Krishnan

Keyword(s):

Optical Microscopy ◽

Polarization State ◽

Three Dimensional ◽

Polarized Light ◽

Dark Field ◽

Optical Methods ◽

Transverse Waves ◽

Dark Field Imaging ◽

Propagation Of Light ◽

Scanning Optical Microscopy

Propagation of light is described as the simple harmonic motion of transverse waves. Combining waves that propagate on orthogonal planes give rise to linear, elliptical, or spherical polarization, depending on their amplitudes and phase differences. Classical experiments of Huygens and Young demonstrated the principle of optical interference and diffraction. Generalization of Fraunhofer diffraction to scattering by a three-dimensional arrangement of atoms in crystals forms the basis of diffraction methods. Fresnel diffraction finds application in the design of zone plates for X-ray microscopy. Optical microscopy, with resolution given by the Rayleigh criterion to be approximately half the wavelength, works best when tailored to the optimal characteristics of the human eye (λ = 550 nm). Lenses suffer from spherical and chromatic aberrations, and astigmatism. Optical microscopes operate in bright-field, oblique, and dark-field imaging conditions, produce interference contrast, and can image with polarized light. Variants include confocal scanning optical microscopy (CSOM). Metallography, widely used to characterize microstructures, requires polished or chemically etched surfaces to provide optimal contrast. Finally, the polarization state of light reflected from the surface of a specimen is utilized in ellipsometry to obtain details of the optical properties and thickness of thin film materials.

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A Novel Three-Dimensional Visual Inspection Scheme for Defect Detection of Transparent Materials Based on the Digital Holographic Microscopy

International Multidisciplinary Microscopy Congress - Springer Proceedings in Physics ◽

10.1007/978-3-319-04639-6_6 ◽

2014 ◽

pp. 37-44

Author(s):

Kwang-Beom Seo ◽

Byung-Mok Kim ◽

Jung-Sik Koo ◽

Eun-Soo Kim

Keyword(s):

Defect Detection ◽

Visual Inspection ◽

Three Dimensional ◽

Digital Holographic Microscopy ◽

Holographic Microscopy ◽

Transparent Materials

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Development of a Combined Scanning Ion-Conductance and Nearfield Optical Microscope to Image Living Cells

Microscopy and Microanalysis ◽

10.1017/s1431927600018201 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 976-977

Author(s):

M. Raval ◽

D. Klenerman ◽

T. Rayment ◽

Y. Korchev ◽

M. Lab

Keyword(s):

Optical Microscopy ◽

Biological Samples ◽

Near Field ◽

Sample Surface ◽

Optical Microscope ◽

Ion Conductance ◽

Simultaneous Generation ◽

Simple Arrangement ◽

Wavelength Resolution ◽

Sub Wavelength

It is important to be able to image biological samples in a manner that is non-invasive and allows the sample to retain its functionality during imaging.A member of the SPM (scanning probe microscopy) family, SNOM (scanning near-field optical microscopy), has emerged as a technique that allows optical and topographic imaging of biological samples whilst satisfying the above stated criteria. The basic operating principle of SNOM is as follows. Light is coupled down a fibre-optic probe with an output aperture of sub-wavelength dimensions. The probe is then scanned over the sample surface from a distance that is approximately equal to the size of its aperture. By this apparently simple arrangement, the diffraction limit posed by conventional optical microscopy is overcome and simultaneous generation of optical and topographic images of sub-wavelength resolution is made possible. Spatial resolution values of lOOnm in air and 60nm in liquid[1,2] are achievable with SNOM.

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Challenges in a Hybrid Fabrication Process to Generate Metallic Polarization Elements with Sub-Wavelength Dimensions

Materials ◽

10.3390/ma13225279 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5279

Author(s):

Stefan Belle ◽

Babette Goetzendorfer ◽

Ralf Hellmann

Keyword(s):

Final Height ◽

Three Dimensional ◽

Fabrication Process ◽

Degree Of Polarization ◽

Direct Laser Writing ◽

Free Standing ◽

Laser Writing ◽

Additive Fabrication ◽

Direct Laser ◽

Sub Wavelength

We report on the challenges in a hybrid sub-micrometer fabrication process while using three dimensional femtosecond direct laser writing and electroplating. With this hybrid subtractive and additive fabrication process, it is possible to generate metallic polarization elements with sub-wavelength dimensions of less than 400 nm in the cladding area. We show approaches for improving the adhesion of freestanding photoresist pillars as well as of the metallic cladding area, and we also demonstrate the avoidance of an inhibition layer and sticking of the freestanding pillars. Three-dimensional direct laser writing in a positive tone photoresist is used as a subtractive process to fabricate free-standing non-metallic photoresist pillars with an area of about 850 nm × 1400 nm, a height of 3000 nm, and a distance between the pillars of less than 400 nm. In a subsequent additive fabrication process, these channels are filled with gold by electrochemical deposition up to a final height of 2200 nm. Finally, the polarization elements are characterized by measuring the degree of polarization in order to show their behavior as quarter- and half-wave plates.

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A miniaturized optical tomography platform for volumetric imaging of engineered living systems

Lab on a Chip ◽

10.1039/c8lc01190g ◽

2019 ◽

Vol 19 (4) ◽

pp. 550-561 ◽

Cited By ~ 4

Author(s):

Adem Polat ◽

Shabir Hassan ◽

Isa Yildirim ◽

Luis Eduardo Oliver ◽

Maryam Mostafaei ◽

...

Keyword(s):

Optical Microscopy ◽

Biological Sample ◽

Optical Tomography ◽

Three Dimensional ◽

Living Systems ◽

Volumetric Imaging ◽

Non Invasive ◽

3D Information

Volumetric optical microscopy approaches that enable acquisition of three-dimensional (3D) information from a biological sample are attractive for numerous non-invasive imaging applications.

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