1. Articles in category: Other Non-Medical

    1-24 of 263 1 2 3 4 ... 9 10 11 »
    1. Optical coherence tomography imaging of plant root growth in soil

      Optical coherence tomography imaging of plant root growth in soil

      Complex interactions between roots and soil provide the nutrients and physical support required for robust plant growth. Yet, visualizing the root–soil interface is challenged by soil’s opaque scattering characteristics. Herein, we describe methods for using optical coherence tomography (OCT) to provide non-destructive 3D and cross-sectional root imaging not available with traditional bright-field microscopy. OCT is regularly used for bioimaging, especially in ophthalmology, where it can detect retinal abnormalities. Prior use of OCT in plant biology has focused on surface defects of above-ground tissues, predominantly in food crops. Our results show OCT is also viable for detailed, in situ ...

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    2. A Flexible Touch-based Fingerprint Acquisition Device and A Benchmark Database using Optical Coherence Tomography

      A Flexible Touch-based Fingerprint Acquisition Device and A Benchmark Database using Optical Coherence Tomography

      Optical Coherence Tomography (OCT) is a high resolution imaging technology probing the internal structure of multilayered tissues. Since it provides subsurface fingerprint information which is identical to the surface texture but unaffected by any surface defects, OCT-based fingerprints open up a new domain for establishing robust and high security automatic fingerprint identification systems (AFISs). However, the development of OCT-based fingerprint recognition is hindered by the lack of public OCT-based fingerprint database for algorithm analysis and testing. This paper, for the first time, established an OCT-based fingerprint database with thousands of fingers using our custom-built acquisition device.(The website of this ...

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    3. Integrated terahertz radar based on leaky-wave coherence tomography

      Integrated terahertz radar based on leaky-wave coherence tomography

      Terahertz wave radar offers a higher resolution and smaller aperture compared with microwave radar. However, despite the emergence of terahertz sources and detectors suitable for radar front ends, the integration of a phased-array radar system remains challenging due to the lack of phase shifters and circulators, the basic components for beam steering and input–output isolation. Here we show that leaky-wave coherence tomography, which can integrate a terahertz radar system using a pair of reverse-connected leaky-wave antennas, can be used to implement beam steering and homodyne detection in one package. Our approach can detect direction and range without using phase ...

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    4. Compact and Mobile Full-Field Optical Coherence Tomography Sensor for Subsurface Fingerprint Imaging

      Compact and Mobile Full-Field Optical Coherence Tomography Sensor for Subsurface Fingerprint Imaging

      Conventional fingerprint sensors that are deployed in real-life applications lack the ability to peer inside a finger beyond the external surface. Subsurface information can provide complimentary biometric characteristics associated with the finger. The subsurface fingerprints can also be employed when the quality of the external/surface fingerprints is affected. One of the most promising technologies for imaging below the surface of an external fingerprint is full-field optical coherent tomography (FF-OCT). However, the FF-OCT can be expensive and cumbersome, despite its proven ability for biometric use. In this paper, we describe the design and implementation of a compact, mobile and cost-effective ...

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    5. Acquisition and Extraction of Surface and Internal Fingerprints from Optical Coherence Tomography through 3D Fully Convolutional Network

      Acquisition and Extraction of Surface and Internal Fingerprints from Optical Coherence Tomography through 3D Fully Convolutional Network

      Optical coherence tomography (OCT) is a non-destructive, high-resolution, and non-invasive imaging technique that has recently been applied to biometric field for three dimensional (3D) fingertip data acquisition. Fingertip volume data contains the epidermis and part of the dermis layers representing the surface fingerprint and internal fingerprint, respectively. As a 3D and under skin feature, internal fingerprint provides much higher anti-counterfeiting capability compared with traditional 2D fingerprints. Furthermore, it is not affected by fingertip conditions such as wet, worn out (old) and small scars/injuries. However, the extraction of surface and internal fingerprints is challenging due to the speckle noise and ...

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    6. Frequency-domain optical coherence tomography system in the terahertz region

      Frequency-domain optical coherence tomography system in the terahertz region

      In this study, a frequency-domain optical coherence tomography (FD-OCT) system in the terahertz frequency range was developed. To generate tunable continuous-wave terahertz radiation, the outputs of two near-infrared external cavity diode lasers were mixed in an antenna-coupled photo-mixer. Using the FD-OCT system, tomographic profiling of the front and back surfaces of a high-resistivity silicon plate was realized.

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      Mentions: Osaka University
    7. Identification of Fungus-infected Tomato Seeds Based on Full-Field Optical Coherence Tomography

      Identification of Fungus-infected Tomato Seeds Based on Full-Field Optical Coherence Tomography

      The morphological changes of anthracnose (fungus) -infected tomato seeds have been studied to identify the infection and characterize its effect. Full-field optical coherence tomography (FF-OCT) has been utilized as a nondestructive but efficient modality for visualizing the effects of fungal infection. The cross-sectional images extracted from a stack of en face FF-OCT images showed significant changes with infection in the seed structure. First of all, the seed coat disappeared with the infection. The thickness of the seed coat of a healthy seed was measured as 28.2 µm, with a standard deviation of 1.2 µm. However, for infected seeds ...

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    8. Investigation of sputtering target re-deposits by Optical Coherence Tomography and Grazing Incident X-ray Diffraction

      Investigation of sputtering target re-deposits by Optical Coherence Tomography and Grazing Incident X-ray Diffraction

      The sputtering target re-deposit grown by cumulative sputtering has been investigated in this work by studying both fresh and rigorously sputtered zirconium oxide target by Fourier Domain Optical Coherence Tomography (FDOCT), a depth resolved optical imaging modality. The Optical Coherence Tomography (OCT) depth profiles have further been analyzed to extract optical attenuation coefficient of sputtered target surface as well as fresh target surface. Re-deposited sputtered target surface shows larger optical attenuation coefficient in the range of 1.5-4.4 mm −1 as opposed to that of 1.1 mm −1 for fresh ZrO 2 target. The same sputtered target surfaces ...

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      Mentions: K. Divakar Rao
    9. 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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    10. 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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    11. 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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    12. 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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    13. 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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    14. 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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    15. 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
    16. 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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    17. 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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    18. 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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    19. 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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    20. 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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    21. 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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    22. 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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    23. 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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    24. 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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    1-24 of 263 1 2 3 4 ... 9 10 11 »
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