Recognition of Direction of New Apertures from the Elongated Speckle Images: Simulation

Hamed, A. A.

doi:10.4236/opj.2013.33040

Cited by 8 publications

(3 citation statements)

References 13 publications

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“…As the speckles have an irregular, random shape and a distribution of sizes, only an average speckle size can be estimated. This is done for example by determining the spatial frequency at the maximum of the power spectrum [86,87,123,129] or from a 2D auto-correlation of the speckle pattern [88,128,[130][131][132][133][134]. Generally, well-defined, small speckles that can be resolved easily and cover a few pixels in the detector plane are desired.…”

Section: Introductionmentioning

confidence: 99%

State of the Art of X-ray Speckle-Based Phase-Contrast and Dark-Field Imaging

Zdora

2018

J. Imaging

106

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Abstract:In the past few years, X-ray phase-contrast and dark-field imaging have evolved to be invaluable tools for non-destructive sample visualisation, delivering information inaccessible by conventional absorption imaging. X-ray phase-sensing techniques are furthermore increasingly used for at-wavelength metrology and optics characterisation. One of the latest additions to the group of differential phase-contrast methods is the X-ray speckle-based technique. It has drawn significant attention due to its simple and flexible experimental arrangement, cost-effectiveness and multimodal character, amongst others. Since its first demonstration at highly brilliant synchrotron sources, the method has seen rapid development, including the translation to polychromatic laboratory sources and extension to higher-energy X-rays. Recently, different advanced acquisition schemes have been proposed to tackle some of the main limitations of previous implementations. Current applications of the speckle-based method range from optics characterisation and wavefront measurement to biomedical imaging and materials science. This review provides an overview of the state of the art of the X-ray speckle-based technique. Its basic principles and different experimental implementations as well as the the latest advances and applications are illustrated. In the end, an outlook for anticipated future developments of this promising technique is given.

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Section: Introductionmentioning

confidence: 99%

State of the Art of X-ray Speckle-Based Phase-Contrast and Dark-Field Imaging

Zdora

2018

J. Imaging

106

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“…As the speckles have an irregular, random shape and a distribution of sizes, only an average speckle size can be estimated. This is done, for example, by determining the spatial frequency at which the power spectrum shows a maximum in Fourier space [Cerbino et al, 2008;Wang et al, 2016c,b] or via 2D autocorrelation of the speckle pattern in real space [Goodman, 1984;Alexander et al, 1994;Hamed, 2013;Zdora et al, , 2017bAloisio et al, 2015]. Generally, well-defined, small speckles that can be resolved easily and cover a few pixels in the detector plane are desired.…”

Section: Background and Introductionmentioning

confidence: 99%

X-ray Phase-Contrast Imaging Using Near-Field Speckles

Zdora¹

2021

Springer Theses

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In the last decades, X-ray phase-contrast imaging has proven to be a powerful method for unveiling the inner structure of samples and is capable of visualising even minute density differences. Recently, speckle-based imaging (SBI), the youngest X-ray phase-sensitive technique, has received great interest due to its high sensitivity, quantitative character and relaxed requirements on the setup components and beam properties. This thesis is focussed on the development, experimental optimisation and applications of SBI, with the aim of simplifying its implementation, increasing its flexibility and expanding its potential.For this, a robust, flexible data acquisition and reconstruction approach, the unified modulated pattern analysis (UMPA), was developed, which lifts previous constraints of SBI. UMPA allows for tuning of the sensitivity and spatial resolution by adjusting the scan and reconstruction parameters. It is applicable not only to random speckle, but also periodic interference patterns, bridging the gap and improving the performance of both speckle-and single-grating-based techniques.Following the first demonstration of UMPA, its potential for a range of applications is illustrated in this thesis. It is shown that UMPA can be employed for X-ray optics characterisation to quantify aberrations in the focussing behaviour of X-ray refractive lenses with high precision and accuracy. UMPA phase tomography is applied to the field of biomedical imaging for high-sensitivity three-dimensional (3D) virtual histology of unstained, hydrated soft tissue, giving unprecedented structural and quantitative density information.Further developments of SBI explored in this thesis include the testing of novel customisable speckle diffusers, the extension of SBI to higher X-ray energies for geology and materials science applications, and the demonstration of UMPA at a laboratory X-ray source. These progresses promise new possibilities of SBI for high-sensitivity, robust and high-throughput imaging in previously inaccessible fields and make SBI accessible to a wider range of users in research and industry.

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“…Particularly, bio-mimicry of desert beetle needs the elongated spindle like speckles. Though there are reported works on speckles with different aspect ratios, the spindle speckles were not realized till date [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Speckle lithography for fabricating biomimetic spindle structures of desert beetle skin

Bingi

Murukeshan

2017

Biomed. Phys. Eng. Express

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The desert beetle or namib beetle has inspired the scientific community for decades due to its water collecting, harvesting and frost control capabilities. The exact and robust bio-mimicry of this surface is challenging and essential for a better understanding of surface processes and to align them with the significant applications. This paper realizes the fabrication of such structures by a novel concept of integrating the shape engineered spindle speckles with photo-lithography. The uniformly shaped spindle speckle patterns are achieved using a 'diffuser-lens-aperture' optical configuration. It is demonstrated that the fabricated structures that mimic the desert beetle skin are exhibiting excellent super hydrophobic properties. The obtained results also indicate that these structures can be tailored for open air fluidic channels in lab-on-chip and clinical applications.

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Recognition of Direction of New Apertures from the Elongated Speckle Images: Simulation

Cited by 8 publications

References 13 publications

State of the Art of X-ray Speckle-Based Phase-Contrast and Dark-Field Imaging

State of the Art of X-ray Speckle-Based Phase-Contrast and Dark-Field Imaging

X-ray Phase-Contrast Imaging Using Near-Field Speckles

Speckle lithography for fabricating biomimetic spindle structures of desert beetle skin

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