Fundamental aspects of resolution and precision in vertical scanning white-light interferometry

Lehmann, Peter; Tereschenko, Stanislav; Xie, Weichang

doi:10.1088/2051-672x/4/2/024004

Cited by 64 publications

(49 citation statements)

References 26 publications

(36 reference statements)

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“…To obtain correct values of rates and their statistical distributions, a 7 × 7 median filter plus a de-spiking filtering process was applied before the material flux calculations using SPIP (Image Metrology A/S). This filter eliminates VSI data spikes that typically occur due to system inherent optical disturbance effects such as batwings and interferometric slope effects [29]. A typical example of the filtering process can be seen in Figure S3 of Supplementary Material.…”

Section: Surface Retreat Maps (∆H) Reaction Rate Maps (R) and Rate Smentioning

confidence: 99%

A Statistical Approach for Analysis of Dissolution Rates Including Surface Morphology

2019

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Understanding mineral dissolution is relevant for natural and industrial processes that involve the interaction of crystalline solids and fluids. The dissolution of slow dissolving minerals is typically surface controlled as opposed to diffusion/transport controlled. At these conditions, the dissolution rate is no longer constant in time or space, an outcome observed in rate maps and correspondent rate spectra. The contribution and statistical prevalence of different dissolution mechanisms is not known. Aiming to contribute to close this gap, we present a statistical analysis of the variability of calcite dissolution rates at the nano- to micrometer scale. A calcite-cemented sandstone was used to perform flow experiments. Dissolution of the calcite-filled rock pores was measured using vertical scanning interferometry. The resultant types of surface morphologies influenced the outcome of dissolution. We provide a statistical description of these morphologies and show their temporal evolution as an alternative to the lack of rate spatial variability in rate constants. Crystal size impacts dissolution rates most probably due to the contribution of the crystal edges. We propose a new methodology to analyze the highest rates (tales of rate spectra) that represent the formation of deeper etch pits. These results have application to the parametrization and upscaling of geochemical kinetic models, the characterization of industrial solid materials and the fundamental understanding of crystal dissolution.

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Section: Surface Retreat Maps (∆H) Reaction Rate Maps (R) and Rate Smentioning

confidence: 99%

A Statistical Approach for Analysis of Dissolution Rates Including Surface Morphology

2019

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“…It should be possible to employ and improve automated instrument controls that are used in mechanized quality checks for some industrial processes 2 to simplify instrument use. The resulting surface profile images may also include imaging artifacts such as the batwing or interferometric slope effects 25 . While many of these effects can be corrected with appropriate filtering, over processing the data can also lead to filtering artefacts (such as vignetting) in the images and to misinterpretation of the data.…”

Section: Resultsmentioning

confidence: 99%

Rapid nondestructive measurement of bacterial cultures with 3D interferometric imaging

Larimer

Brann

Powell

et al. 2019

Sci Rep

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The agar culture plate has played a crucial role in bacteriology since the origins of the discipline and is a staple bioanalytical method for efforts ranging from research to standard clinical diagnostic tests. However, plating, inoculating, and waiting for microbes to develop colonies that are visible is time-consuming. In this work, we demonstrate white-light interferometry (WLI) as a practical tool for accelerated and improved measurement of bacterial cultures. High resolution WLI surface profile imaging was used for nondestructive characterization and counting of bacterial colonies on agar before they became visible to the naked eye. The three-dimensional (3D) morphology of Gram-negative ( Pseudomonas fluorescens ) and Gram-positive ( Bacillus thuringiensis ) bacterial species were monitored with WLI over time by collecting surface profiles of colonies on agar plates with high vertical resolution (3–5 nanometers) and large field of view (3–5 mm). This unique combination of sensitive vertical resolution and large field of view uniquely provided by WLI enables measurement of colony morphologies and nondestructive monitoring of hundreds of microcolonies. Individual bacteria were imaged within the first few hours after plating and colonies were accurately counted with results comparing favorably to counts made by traditional methods that require much longer wait times. Nondestructive imaging was used to track single cells multiplying into small colonies and the volume changes over time in these colonies were used to measure their growth rates. Based on the results herein, bioimaging with WLI was demonstrated as a novel rapid bacterial culture assay with several advantageous capabilities. Fast nondestructive counting of colony-forming units in a culture and simultaneous measurement of bacterial growth rates and colony morphology with this method may be beneficial in research and clinical applications where current methods are either too slow or are destructive.

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“…The interference fringes can be sensed for each surface point correlated to each pixel of the imaging camera. By vertically scanning the interferometric objective lens using a piezoelectric actuator, a surface topography map can be determined by finding the best equal-path condition at each pixel in the imaging camera [25,26].…”

Section: Coherence Scanning Interferometermentioning

confidence: 99%

Surface Topography Measurement of Mirror-Finished Surfaces Using Fringe-Patterned Illumination

Fang

Tjahjowidodo

2020

Metals

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Mirror-finished surface products have a wide range of applications in different engineering industries, such as power generation, aerospace, semiconductors and optics. The surface topography of mirror-finished products is typically measured in a metrology laboratory, which is typically time consuming and cannot be integrated into the manufacturing process. To allow for in-situ product quality assurance and automatic tool change for manufacturing processes, a more accurate and responsive surface-measurement method is needed. For highly polished surfaces, a sub-micron surface fluctuation makes it possible to use light-scattering effects and image processing for surface texture analysis. A non-contact surface inspection system using a fringe-patterned illumination method is proposed in this paper. A predesigned pattern was projected onto the target surface, and its reflected image was captured by a camera. It was found that the surface parameters Sa and Sq, which are widely used to evaluate surface quality, are significantly correlated with luminous-intensity distribution. Another parameter, Str, which quantifies the uniformity of surface-texture directions due to polishing or grinding marks, was traditionally quantified after a complete-surface topographic measurement. In this research, a new approach is proposed to determine surface isotropy through a luminance-intensity distribution analysis. By rotating the test coupon, the variation of specular reflection showed correlation with the significance of surface-texture direction. The experimental results demonstrate that mirror-finished surfaces with a large deviation in luminance intensity across the pattern possess low Str values, which indicates low uniformity in surface texture.

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Fundamental aspects of resolution and precision in vertical scanning white-light interferometry

Cited by 64 publications

References 26 publications

A Statistical Approach for Analysis of Dissolution Rates Including Surface Morphology

A Statistical Approach for Analysis of Dissolution Rates Including Surface Morphology

Rapid nondestructive measurement of bacterial cultures with 3D interferometric imaging

Surface Topography Measurement of Mirror-Finished Surfaces Using Fringe-Patterned Illumination

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