Digital holography and quantitative phase contrast imaging using computational shear interferometry

Falldorf, Claas; Agour, Mostafa; Bergmann, Ralf B.

doi:10.1117/1.oe.54.2.024110

Cited by 53 publications

(28 citation statements)

References 11 publications

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“…Finally significant progress is achieved by wavefront modulation using spatial light modulators. Reference wave variations without mechanically moving parts are feasible, as is successfully introduced in digital holographic shearing interferometry [9].…”

Section: Discussionmentioning

confidence: 99%

“…. , s N by solving an inverse problem [9]. The application of a gradient based iterative optimization procedure gives the solution at least close to the global minimum.…”

Section: Computational Shear Interferometrymentioning

confidence: 99%

“…The first object investigated by this method is an onion skin showing its epidermal cells. Corresponding phase modulo 2π, demodulated phase inside the box [9].…”

Section: Shearographic Differential Interference Contrast Microscopymentioning

confidence: 99%

“…They enable the generation of optical diffraction fields from computer generated holograms and thus offer unprecedented capabilities of varying optical wave fields in metrology. Thus the reference wave used in holographic applications can be altered without mechanical motion of any components [9].…”

Section: Introductionmentioning

confidence: 99%

“…10 shear-interferograms have been recorded with shears varying in orientation and in magnitude between 1 Experimental arrangement for quantitative phase contrast imaging based on differential interference contrast (DIC) microscopy consisting of a shear interferometer and a microscope objective[9].pixels of the CCD. After the iteration process introduced in Sec.…”

mentioning

confidence: 99%

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Application of Digital Holography for Nondestructive Testing and Metrology: A Review

Kreis

2016

IEEE Trans. Ind. Inf.

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Holography and holographic interferometry as means for nondestructive testing as well as a metrologic tool in engineering, biology, and other fields has got significant momentum by the introduction of digital holography and furtheron by the employment of numerical processing power, which became available due to the increase in speed and data capacity of modern computers. In this review paper we present the basics of holography, holographic interferometry and digital holography and give examples from such diverse fields as deformation analysis, form determination, refractive index measurement, and wave front reconstruction by shearographic differential interference contrast microscopy.Index Terms-Digital holography, holographic interferometry, nondestructive testing, deformation measurement, strain and stress measurement, shearography, fiber testing. ✦ 1551-3203 (c)

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Section: Discussionmentioning

confidence: 99%

“…. , s N by solving an inverse problem [9]. The application of a gradient based iterative optimization procedure gives the solution at least close to the global minimum.…”

Section: Computational Shear Interferometrymentioning

confidence: 99%

“…The first object investigated by this method is an onion skin showing its epidermal cells. Corresponding phase modulo 2π, demodulated phase inside the box [9].…”

Section: Shearographic Differential Interference Contrast Microscopymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Application of Digital Holography for Nondestructive Testing and Metrology: A Review

Kreis

2016

IEEE Trans. Ind. Inf.

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Quality Control and Characterization

Maaß

Piotrowska-Kurczewski

Agour

et al. 2019

Lecture Notes in Production Engineering

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Quality inspection is an essential tool for quality assurance during production. In the microscopic domain, where the manufactured objects have a size of less than 1 mm in at least two dimensions, very often mass production takes place with high demands regarding the failure rate, as micro components generally form the basis for larger assemblies. Especially when it comes to safety-relevant parts, e.g. in the automobile or medical industry, a 100% quality inspection is mandatory. Here, we present a robust and precise metrology method comprised of a holographic contouring system with fast algorithms for geometric evaluation and surface defect detection that paves the way for inspecting cold formed micro parts in less than a second. Using a telecentric lens instead of a standard microscope objective, we compensate scaling effects and wave field curvature, which distort the reconstruction in digital holographic microscopy. To enhance the limited depth of focus of the microscope objective, depth information from different object layers is stitched together to yield 3D data of its complete geometry. The 3D data map is converted into a point cloud and processed by geometry and surface inspection. Thereby, the resulting point cloud data are automatically decomposed into geometric primitives in order to analyze geometric deviations. Additionally, the surface itself is checked for scratches and other defects by the use of convolutional neural networks. The developed machine learning algorithm makes it possible not only to distinguish between good and failed parts but also to show the defect area pixel-wise. The methods are demonstrated by quality inspection of cold formed micro cups. Defects larger than 2 lm laterally and 5 lm axially can be detected.

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Distortion-free laser beam shaping for material processing using a digital micromirror device

Messaoudi

Thiemicke

Falldorf

et al. 2017

Prod. Eng. Res. Devel.

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Digital holography and quantitative phase contrast imaging using computational shear interferometry

Cited by 53 publications

References 11 publications

Application of Digital Holography for Nondestructive Testing and Metrology: A Review

Application of Digital Holography for Nondestructive Testing and Metrology: A Review

Quality Control and Characterization

Distortion-free laser beam shaping for material processing using a digital micromirror device

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