1. Articles in category: Other Non-Medical

    1-24 of 255 1 2 3 4 ... 9 10 11 »
    1. Method to characterize cut gemstones using optical coherence tomography

      Method to characterize cut gemstones using optical coherence tomography

      The invention includes an improvement in a method of assessing a gemstone having at least one planar face with an internally reflecting surface including the steps of optically modifying the at least one planar face of the gemstone to return a sample beam from an internally reflecting plane corresponding to the at least one planar face to an optical coherence tomography (OCT) system; selectively directing the sample beam from an optical coherence tomography (OCT) system onto the gemstone; and generating an OCT image map of the gemstone to determine volume, gem carat weight and/or quality.

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    2. Assessing internal fouling during microfiltration optical coherence tomography and evapoporometry

      Assessing internal fouling during microfiltration optical coherence tomography and evapoporometry

      The internal fouling of membranes is typically presumed and inferred, but the direct characterization of representative samples is challenging. This study targeted to assess internal fouling using the Optical Coherence Tomography (OCT) and Evapoporometry (EP) techniques for real-time monitoring during filtration and off-line measurement of the pore size distributions (PSDs) of the fouled membranes, respectively. The results were validated by atomic force microscopy (AFM) measurements and also the three-mechanism fouling model. The foulant used was the well-studied bovine serum albumin (BSA), while the membranes were three commercially available polymeric microfiltration membranes with similar nominal pore sizes and porosities. Although the ...

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    3. Machining head for a laser machining device

      Machining head for a laser machining device

      The invention relates to a machining head for a laser machining device, which is equipped for machining a workpiece (24) using laser radiation (30). The laser machining head comprises an adjustable focusing optical unit (34), which focuses the laser radiation (30) in a focal spot (22). The distance between the focal spot (22) and a machining head can be modified by modifying the focal length of the focusing optical unit (34). A scanning apparatus (44) deflects the laser radiation (30) in different directions. An optical coherence tomography device (48) measures a distance between the treatment head and the workpiece (24 ...

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    4. 3D Fingerprint Gender Classification Using Deep Learning

      3D Fingerprint Gender Classification Using Deep Learning

      Optical Coherence Tomography (OCT) is a high resolution imaging technology, which provides a 3D representation of the fingertip skin. This paper for the first time investigates gender classification using those 3D fingerprints. Different with current fingerprint gender classification methods, the raw multiple longitudinal( X - Z ) fingertip images of one finger can be applied instead of studying features extracted from fingerprints, and the model can be trained effectively when the training data set is relatively small. Experimental results show that the best accuracy of 80.7% is achieved by classifying left fore finger on a small database with 59 persons. Meanwhile ...

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    5. Electromagnetic analysis for optical coherence tomography based through silicon vias metrology

      Electromagnetic analysis for optical coherence tomography based through silicon vias metrology

      This paper reports on progress in the analysis of time-domain optical coherence tomography (OCT) applied to the dimensional metrology of through-silicon vias (TSVs), which are vertical interconnect accesses in silicon, enabling three-dimensional (3D) integration in microelectronics, and estimates the deviations from earlier, simpler models. The considered TSV structures are 1D trenches and circular holes etched into silicon with a large aspect ratio. As a prerequisite for a realistic modeling, we work with spectra obtained from reference interferograms measured at a planar substrate, which fully includes the dispersion of the OCT apparatus. Applying a rigorous modal approach, we estimate the differences ...

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    6. Separation of Overlapping Fingerprints in Multilayered Carrier Using Optical Coherence Tomography

      Separation of Overlapping Fingerprints in Multilayered Carrier Using Optical Coherence Tomography

      Fingerprints lifted from crime scenes are often overlapped because of multiple impressions of fingers. Current methods to separate overlapping fingerprints are primarily based on algorithms that estimate the orientation field of component prints. However, these methods need human intervention, and the accuracy of the separation may easily be degraded. In this paper, a novel tomographic imaging technique, optical coherence tomography (OCT), was used to separate overlapping fingerprints intuitively and noninvasively. The OCT system was also applied to reveal a hidden blood fingerprint that was completely covered by one layer of nontransparent paint. An additional experiment was conducted using a piece ...

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    7. PHD POSITION – OPTICAL COHERENCE TOMOGRAPHY ON AGRO-FOOD PRODUCTS

      PHD POSITION – OPTICAL COHERENCE TOMOGRAPHY ON AGRO-FOOD PRODUCTS

      (ref. BAP-2019-576) The MeBioS group performs groundbreaking research on innovative sensor technologies and the associated data analysis methods to understand and control the quality of products and ongoing processes. The research on sensors mainly focusses on optical sensor systems (spectroscopy, hyperspectral imaging, thermography, smart cameras,…). While the data research involves the optimal design of experiments, chemometrics, process monitoring and control, as well as artificial intelligence and deep learning. OCT/OCM is a challenging new technique for non-destructive 3D imaging of biological tissues, without the need for sample preparation! Project Monitoring living tissues and organisms for an extended period of time ...

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      Mentions: K. U. Leuven
    8. Optical properties of human milk

      Optical properties of human milk

      With human milk being the most important source of infant nutrition, the protection and support of breastfeeding are essential from a global health perspective. Nevertheless, relatively few objective methods are available to investigate human milk composition and lactation physiology when a mother experiences breastfeeding problems. We argue that optics and photonics offer promising opportunities for this purpose. Any research activity within this new application field starts with a thorough understanding on how light interacts with human milk. Therefore, the aim of this study was to investigate the full set of optical properties for human milk and the biological variability therein ...

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    9. Optical coherence tomography in forensic sciences: a review of the literature

      Optical coherence tomography in forensic sciences: a review of the literature

      Optical coherence tomography (OCT) is an interferometric imaging technique that has revolutionized clinical ophthalmology since the first half of the 1990’s. Despite this approach being successfully employed in ophthalmology and having great potential in forensic cases, its use in different forensic fields appears to be quite limited. In this review we reviewed the scientific literature regarding the application of OCT in forensic science and legal medicine from 1995 to 2019. Our research showed the usefulness of this approach for the study of coronary injuries, postmortem ocular changes, forensic entomology, and several other applications of specific forensic interest (the study ...

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    10. Subsurface and Layer Intertwined Template Protection Using Inherent Properties of Full-Field Optical Coherence Tomography Fingerprint Imaging

      Subsurface and Layer Intertwined Template Protection Using Inherent Properties of Full-Field Optical Coherence Tomography Fingerprint Imaging

      The emergence of Full Field-Optical Coherence Tomography (FF-OCT) for fingerprint imaging has shown it’s ability in addressing and solving the drawbacks of traditional fingerprinting solutions such as spoofing attacks, low accuracy for abraded fingerprint. With the availability of multiple internal fingerprints (from subsurface captured at different depths), it is also essential to consider the aspects of ideal biometrics where the privacy of the fingerprint data is preserved. In this work, we propose a new framework for fingerprint template protection, highly customized to FF-OCT by exploring the interplay between subsurface. As a first of it’s kind work attempting template ...

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    11. NinePoint Medical Announces Publication of 1000 Patient Registry Study

      NinePoint Medical Announces Publication of 1000 Patient Registry Study

      NinePoint Medical, Inc, a transformative medical device company pioneering the use of Optical Coherence Tomography (OCT) for gastrointestinal applications, today announced the publication of their 1000 patient Volumetric Laser Endomicroscopy (VLE) Registry study focused on Barrett’s Esophagus. The 18 site study, published in Diseases of the Esophagus , enrolled 1000 patients between 2014 and 2016 for imaging using the NvisionVLE® Imaging System. The study was designed to determine usage patterns of VLE in clinical practice and to estimate quantitative and qualitative performance metrics, with this publication focused on Barrett’s Esophagus. All enrolled patients were examined with standard upper endoscopy ...

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    12. Optical computing optical coherence tomography with conjugate suppression by dispersion

      Optical computing optical coherence tomography with conjugate suppression by dispersion

      For all imaging techniques, such as optical coherence tomography (OCT), fast imaging speed is always of high demand. Optical computing OCT ( OC2T) has achieved ultrahigh speed for real time 3D imaging without post data processing, but its spatial resolution is lowered down due to an imperfect Fourier transformation in the optical computing process. In this Letter, we illustrate the theory of OC2T and prove that the dispersion imbalance between reference arm and sample arm may be introduced to improve the resolution. Furthermore, this novel OC2T technique can also enable a conjugate restrained OCT imaging without any data processing, achieving ∼ 2 ...

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    13. High-accurate and robust fingerprint anti-spoofing system using Optical Coherence Tomography

      High-accurate and robust fingerprint anti-spoofing system using Optical Coherence Tomography

      Traditional commercial automated fingerprint recognition systems (AFRSs) are vulnerable to fake attacks by the use of artificial fingerprints, due to its limitation on resolution and the difficulty of obtaining depth information. Developing new systems with strong anti-spoofing ability are of increasing concern in the current digital age. Inspired by the observation and comparison of fingertip skin structure and the one dimensional (1D) depth signals derived from OCT acquisition images between real finger and artificial fingerprints, two novel anti-spoofing features, namely depth-double-peak feature and sub-single-peak feature, were specifically defined. Depth-double-peak feature refers that there must be two and only two peaks ...

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    14. Partially coherent radar unties range resolution from bandwidth limitations

      Partially coherent radar unties range resolution from bandwidth limitations

      It is widely believed that range resolution, the ability to distinguish between two closely situated targets, depends inversely on the bandwidth of the transmitted radar signal. Here we demonstrate a different type of ranging system, which possesses superior range resolution that is almost completely free of bandwidth limitations. By sweeping over the coherence length of the transmitted signal, the partially coherent radar experimentally demonstrates an improvement of over an order of magnitude in resolving targets, compared to standard coherent radars with the same bandwidth. A theoretical framework is developed to show that the resolution could be further improved without a ...

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    15. Low-bandwidth radar technology provides improved detection of objects

      Low-bandwidth radar technology provides improved detection of objects

      Radar technologies were originally designed to identify and track airborne military targets. Today they're more often used to detect motor vehicles, weather formations and geological terrain. Until now, scientists have believed that radar accuracy and resolution are related to the range of frequencies or radio bandwidth used by the devices. But a new Tel Aviv University study finds that an approach inspired by optical coherence tomography (OCT) requires little to no bandwidth to accurately create a high-resolution map of a radar's surrounding environment. "We've demonstrated a different type of ranging system that possesses superior range resolution and ...

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    16. Distributed gas detection utilizing Fourier domain optical coherence based absorption spectroscopy

      Distributed gas detection utilizing Fourier domain optical coherence based absorption spectroscopy

      In this study, a new method called Fourier domain optical coherence based absorption spectroscopy (FD-OCAS) is proposed for distributed gas detection for the first time. Mach-Zehnder interferometer based quasi-distributed structure is developed for proof-concept demonstration and experimental verification. Optical interference happens between reference arm and sensing arms of the constructed Mach-Zehnder interferometer. Different sensing arms coded with different fiber lengths contribute different frequency components in ultimate interference signals. Fourier transform is used to separate each frequency to identify different sensing arms, realizing distributed detection. The amplitudes of Fourier transform are related to the gas absorption levels in corresponding sensing arms ...

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    17. Elucidation of microstructural changes in leaves during senescence using spectral domain optical coherence tomography

      Elucidation of microstructural changes in leaves during senescence using spectral domain optical coherence tomography

      Leaf senescence provides a unique window to explore the age-dependent programmed degradation at organ label in plants. Here, spectral domain optical coherence tomography (SD-OCT) has been used to study in vivo senescing leaf microstructural changes in the deciduous plant Acer serrulatum Hayata . Hayata leaves show autumn phenology and change color from green to yellow and finally red. SD-OCT image analysis shows distinctive features among different layers of the leaves; merging of upper epidermis and palisade layers form thicker layers in red leaves compared to green leaves. Moreover, A-scan analysis showed a significant (p < 0.001) decrease in the attenuation coefficient ...

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      Mentions: Wen-Chuan Kuo
    18. A Micro-Tomographic Insight into the Coating Systems of Historical Bowed String Instruments

      A Micro-Tomographic Insight into the Coating Systems of Historical Bowed String Instruments

      Musical instruments are tools for playing music, but for some of them—made by the most important historical violin makers—the myths hide the physical artwork. Ancient violin-making Masters developed peculiar construction methods and defined aesthetic canons that are still recognizable in their musical instruments. Recently, the focus of scientific investigations has been set on the characterization of materials and methods used by the ancient violin makers by means of several scientific approaches. In this work, the merits of synchrotron radiation micro-computed tomography and optical coherence tomography (OCT) for the investigation of complex coatings systems on historical bowed string musical ...

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    19. Optical Coherence Tomography for Fingerprint Presentation Attack Detection (Book Chapter)

      Optical Coherence Tomography for Fingerprint Presentation Attack Detection (Book Chapter)

      New research in fingerprint biometrics uses optical coherence tomography (OCT) technology to acquire fingerprints from where they originate below the surface of the skin. The penetrative nature of this technology means that rich information is available regarding the structure of the skin. This access, in turn, enables new techniques in detecting spoofing attacks, and therefore also introduces mitigation steps against current presentation attack methods. These techniques include the ability to detect fake fingers; fake layers applied above the skin; differentiate between fakes and surface skin conditions; and liveness detection based on, among others, the analysis of eccrine glands and capillary ...

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    20. Eggshell apex abnormalities caused by two different Mycoplasma synoviae genotypes and evaluation of eggshell anomalies by full-field optical coherence tomography

      Eggshell apex abnormalities caused by two different Mycoplasma synoviae genotypes and evaluation of eggshell anomalies by full-field optical coherence tomography

      Background Mycoplasma synoviae (MS) is an important poultry pathogen worldwide. This bacterium may cause eggshell changes including an altered shell surface, thinning, and increased translucency in different areas, which leads to a greater incidence of eggshell cracks and breaks. In the present study the association between experimental infection of birds with two field strains of MS from different genotypes and the production of abnormal eggs is described. The analysis of those eggshells using a full-field optical coherence tomography (FF OCT) scanner is also reported. Results Eggshell samples were obtained from three experimental groups of chickens: one control and two infected ...

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    21. Optical coherence tomography—A review of the opportunities and challenges for postharvest quality evaluation

      Optical coherence tomography—A review of the opportunities and challenges for postharvest quality evaluation

      Optical Coherence Tomography (OCT) is an established non-destructive and contactless photonic technique which has now been shown to be suitable for monitoring the near-surface internal structure of tissues in stored fruit and vegetables. Such real-time cross-sectional imaging allows for better visualisation and understanding of the temporal changes in internal structure. However, despite these advantages, problems persist around the trade-off between imaging resolution and penetration depth, image analysis and data processing, and the applicability of in situ studies outside of the laboratory setting. This review summarises previous postharvest OCT research and assesses resulting mechanistic outcomes, and future potential.

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      Mentions: K. U. Leuven
    22. Gravity-Driven Flows in Two-Fluid Drops

      Gravity-Driven Flows in Two-Fluid Drops

      The direction in which fluid circulates in binary drops doesn't change when the drops are tilted, implicating gravity—not surface tension—as the driver of flow in these systems. rops of spilled coffee dry and leave behind ring-shaped patterns. The shape and uniformity of these patterns are determined by fluid flows that drive particle deposition within the drops. Now, Fouzia Ouali of Nottingham Trent University in the UK and colleagues have shown that in the case of drops composed of two fluids, gravity, not surface tension, as researchers previously thought, dominates convective flows. The team says that this result ...

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    23. Density-Driven Flows in Evaporating Binary Liquid Droplets

      Density-Driven Flows in Evaporating Binary Liquid Droplets

      In the evaporation of microlitre liquid droplets, the accepted view is that surface tension dominates and the effect of gravity is negligible. We report, through the first use of rotating optical coherence tomography, that a change in the flow pattern and speed occurs when evaporating binary liquid droplets are tilted, conclusively showing that gravitational effects dominate the flow. We use gas chromatography to show that these flows are solutal in nature, and we establish a flow phase diagram demonstrating the conditions under which different flow mechanisms occur.

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    24. Biophotonic approach for the characterization of initial bitter-rot progression on apple specimens using optical coherence tomography assessments

      Biophotonic approach for the characterization of initial bitter-rot progression on apple specimens using optical coherence tomography assessments

      The tremendous advances achieved in the biophotonics technologies have intensified the necessity for non-invasive modalities that can characterize diverse biological materials with increased sensitivity and resolution. Optical coherence tomography (OCT) is one of the techniques that has been applied for biological applications in medicine and agriculture to identify structural properties. Herein, we report the successful incorporation of OCT for the identification of morphological changes that occur as a result of the bitter rot disease, through continuous detection of structural changes. Detailed inner morphological structural changes occurring in fruit specimens were precisely analyzed as a function of the disease incubation period ...

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