1. Articles in category: Other Non-Medical

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    1. Classification of Fingerprints Captured Using Optical Coherence Tomography

      Classification of Fingerprints Captured Using Optical Coherence Tomography

      We propose a technique for analysis of fingerprints scanned free-air (not pressed against a glass) with Optical Coherence Tomography (OCT). Fingerprints from the surface and subdermal parts of the finger are extracted from a 2 GB volumetric scan in cca. 2 s using our specialized technique and GPU acceleration on GeForce GTX 980. The technique provides fingerprints that perform with promising error rates that demonstrate the potential of the OCT for improved fingerprint identification, as well as its potential for prevention of biometric spoofing (PAD).

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    2. Elastic turbulence in entangled semi-dilute DNA solutions measured with optical coherence tomography velocimetry

      Elastic turbulence in entangled semi-dilute DNA solutions measured with optical coherence tomography velocimetry

      The flow instabilities of solutions of high molecular weight DNA in the entangled semi-dilute concentration regime were investigated using optical coherence tomography velocimetry, a technique that provides high spatial (probe volumes of 3.4 pL) and temporal resolution (sub μs) information on the flow behaviour of complex fluids in a rheometer. The velocity profiles of the opaque DNA solutions (high and low salt) were measured as a function of the distance across the gap of a parallel plate rheometer, and their evolution over time was measured. At lower DNA concentrations and low shear rates, the velocity fluctuations were well described ...

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    3. Discriminating hidden bruises in loquat by attenuation coefficients estimated from optical coherence tomography images

      Discriminating hidden bruises in loquat by attenuation coefficients estimated from optical coherence tomography images

      Hidden bruising is considered as one of the difficulties during loquat quality control, which has made an impact on postharvest quality and storability. Optical coherence tomography (OCT) is used as a non-destructive method that acquires 2D images of the sub-surface structure of the loquat. After OCT image processing, the attenuation coefficients ( μ t ) of the regions of interests are fitted to quantitatively analyze the characteristics of loquat tissue through using a confocal signal scattering model from OCT A-scan signals. In this experiment, a total of 60 loquat samples are investigated, with the non-bruised tissue having a large μ t with a mean ...

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    4. Investigation of the internal structure of hemp fibres using optical coherence tomography and Focused Ion Beam transverse cutting

      Investigation of the internal structure of hemp fibres using optical coherence tomography and Focused Ion Beam transverse cutting

      The use of plant fibres in composite applications requires an efficient characterisation of their mechanical properties and thus an accurate description of their internal structure. The review of literature points out that there is still a lack of data on the organisation and structure of bast fibres. In this study, we propose to investigate the internal structure of hemp fibres using two experimental techniques: Focused Ion Beam (FIB) microscopy and optical coherence tomography (OCT). Results indicate that OCT, a non-destructive and non-invasive technique, is a powerful technique to quickly and easily describe the internal structure of fibres and also to ...

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      Mentions: Luc Froehly
    5. Scan-Less Line Field Optical Coherence Tomography, with Automatic Image Segmentation, as a Measurement Tool for Automotive Coatings

      Scan-Less Line Field Optical Coherence Tomography, with Automatic Image Segmentation, as a Measurement Tool for Automotive Coatings

      The measurement of the thicknesses of layers is important for the quality assurance of industrial coating systems. Current measurement techniques only provide a limited amount of information. Here, we show that spectral domain Line Field (LF) Optical Coherence Tomography (OCT) is able to return to the user a cross sectional B-Scan image in a single shot with no mechanical moving parts. To reliably extract layer thicknesses from such images of automotive paint systems, we present an automatic graph search image segmentation algorithm. To show that the algorithm works independently of the OCT device, the measurements are repeated with a separate ...

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      Mentions: Yalin Zheng
    6. Optical Coherence Tomography Reveals Coral Structure, Response to Environmental Stress

      Optical Coherence Tomography Reveals Coral Structure, Response to Environmental Stress

      Brightfield imaging and epifluorescence microscopy have been used to observe living coral, but with limited depth and areal resolution due to the opaque coral tissue, which is composed of different cell layers, and diffuse backscatter from the underlying coral skeleton. Use of visible light for these observations can also impact the coral, e.g., by stimulating photosynthesis or by exposure to potentially harmful UV and blue light. Employing optical coherence tomography (OCT), researchers at the Faculty of Science, University of Copenhagen , have found a way around these obstacles. Michael Kühl of the Department of Biology explained, “OCT is an ...

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    7. In vivo observation of metamorphosis of Plodia interpunctella Hübner using three-dimensional optical coherence tomography

      In vivo observation of metamorphosis of Plodia interpunctella Hübner using three-dimensional optical coherence tomography

      Morphological assessment and three-dimensional reconstructions of internal structures of Plodia interpunctella Hübner during metamorphosis stages were experimentally demonstrated using optical coherence tomography (OCT) for the first time. The conventional, complex sectioning methods were significantly simplified owing to the non-invasive three-dimensional imaging capability of OCT. Further, this study demonstrates the use of OCT as a non-invasive detection tool for in vivo morphological observation of metamorphosis stages to gain a better understanding about the growth of internal organs, which can be considered a useful discovery in the field of entomology. Thus, the metamorphosis stages starting from the larva, three pupa stages ...

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    8. Highly sensitive, wide dynamic range displacement sensor combining chromatic confocal system and phase-sensitive spectral optical coherence tomography

      Highly sensitive, wide dynamic range displacement sensor combining chromatic confocal system and phase-sensitive spectral optical coherence tomography

      A displacement sensor with nanometer-sensitivity and a submillimeter dynamic range is proposed. It integrates a chromatic confocal system and phase-sensitive spectral optical coherence tomography (PhS-SOCT) into the fiber-based Michelson interferometer and codes interference and confocal signals with spectral multiplexing. A displacement is evaluated using depth-resolved phase information decoded from the interference signal, which is unwrapped based on the position information decoded from the confocal signal. A sensor system with a 0.102mm dynamic range was built to validate the method. The temperature induced sample surface displacement was measured with a root mean square error of 3.9nm.

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    9. Breakthrough in live coral imaging

      Breakthrough in live coral imaging

      Corals are calcifying animals and are the prime architects of the most diverse marine ecosystem, the coral reefs. The coral animal harbors tiny microalgae as symbionts in its tissue, where they fix CO2 via photosynthesis and provide the animal host with organic carbon for its respiration. In turn, the microalgae obtain shelter and nutrients in the coral tissue, which extends over a complex calcium carbonate skeleton deposited by the animal host. The coral host takes several measures to optimize light harvesting of its symbionts, while avoiding excess light exposure. This includes tissue contraction and relaxation as well as synthesis of ...

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    10. Secure fingerprint identification based on structural and microangiographic optical coherence tomography

      Secure fingerprint identification based on structural and microangiographic optical coherence tomography

      Optical coherence tomography (OCT) allows noncontact acquisition of fingerprints and hence is a highly promising technology in the field of biometrics. OCT can be used to acquire both structural and microangiographic images of fingerprints. Microangiographic OCT derives its contrast from the blood flow in the vasculature of viable skin tissue, and microangiographic fingerprint imaging is inherently immune to fake fingerprint attack. Therefore, dual-modality (structural and microangiographic) OCT imaging of fingerprints will enable more secure acquisition of biometric data, which has not been investigated before. Our study on fingerprint identification based on structural and microangiographic OCT imaging is, we believe, highly ...

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    11. In vivo imaging of coral tissue and skeleton with optical coherence tomography

      In vivo imaging of coral tissue and skeleton with optical coherence tomography

      Application of optical coherence tomography (OCT) for in vivo imaging of tissue and skeleton structure of intact living corals enabled the non-invasive visualization of coral tissue layers (endoderm versus ectoderm), skeletal cavities and special structures such as mesenterial filaments and mucus release from intact living corals. Coral host chromatophores containing green fluorescent protein-like pigment granules appeared hyper-reflective to near-infrared radiation allowing for excellent optical contrast in OCT and a rapid characterization of chromatophore size, distribution and abundance. In vivo tissue plasticity could be quantified by the linear contraction velocity of coral tissues upon illumination resulting in dynamic changes in the ...

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    12. Holographic microscope, holographic image generation method, and method for acquiring data for holographic image

      Holographic microscope, holographic image generation method, and method for acquiring data for holographic image

      The present method includes a data acquisition process and tomographic image generation processes. In the data acquisition process, holograms of an object light and so forth are acquired for each light with a wavelength by changing the wavelengths of the illumination light, off-axis spherical wave reference light, and inline spherical wave reference light. In the tomographic image generation process, a reconstructed light wave of the object light and a reconstructed light wave of the illumination light on a reconstruction surface are generated from these holograms. A reconstruction light wave with adjusted phase is added up for each wavelength to generate ...

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    13. Optical coherence tomography-integrated, wearable (backpack-type), compact diagnostic imaging modality for in situ leaf quality assessment

      Optical coherence tomography-integrated, wearable (backpack-type), compact diagnostic imaging modality for in situ leaf quality assessment

      We developed a compact, wearable diagnostic imaging modality employing optical coherence tomography for in situ plant leaf quality assessments. This system is capable of diagnosing infected leaves at the initial disease stages. Our system is a versatile backpack-type imaging modality with a compact spectrometer, miniature computer, rechargeable power source, and handheld inspection probe. This method enhances real-time in situ specimen inspection through direct implementation of the imaging modality in a plantation. To evaluate the initial performance, field experiments were conducted in apple, pear, and persimmon plantations. Based on the obtained results, we can conclude that the developed imaging modality can ...

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    14. Feature of the Week 01/23/2017: In-Situ Biofouling Assessment in Spacer Filled Channels Using Optical Coherence Tomography - Biofilm Thickness Mapping

      Feature of the Week 01/23/2017: In-Situ Biofouling Assessment in Spacer Filled Channels Using Optical Coherence Tomography - Biofilm Thickness Mapping

      Biofouling is a one of the major problem in membrane filtration systems. Biofouling leads to performance losses such as reduction of permeate flux, reducing permeate quality, increase in energy consumption, and decreasing of membrane lifetime. Conventional techniques to investigate biofouling involve taking samples by physically breaking up membrane modules and analyzing biofilm build-up. However, this can disrupt the natural process behind biofouling. Therefore, those methods are not able to provide on-line and real-time information about biofilm development. Our research is focused in studying the biofilm development in membrane filtration systems in-situ online under continuous operation using Optical Coherence Tomography (OCT ...

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    15. In-situ biofouling assessment in spacer filled channels using optical coherence tomography (OCT): 3D biofilm thickness mapping

      In-situ biofouling assessment in spacer filled channels using optical coherence tomography (OCT): 3D biofilm thickness mapping

      Membrane systems for water purification can be seriously hampered by biofouling. The use of optical coherence tomography (OCT) to investigate biofilms in membrane systems has recently increased due to the ability to do the characterization in-situ and non-destructively. The OCT biofilm thickness map is presented for the first time as a tool to assess biofilm spatial distribution on a surface. The map allows the visualization and evaluation of the biofilm formation and growth in membrane filtration systems through the use of a false color scale. The biofilm development was monitored with OCT to evaluate the suitability of the proposed approach ...

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    16. Optical sensing method to analyze germination rate of Capsicum annum seeds treated with growth-promoting chemical compounds using optical coherence tomography

      Optical sensing method to analyze germination rate of Capsicum annum seeds treated with growth-promoting chemical compounds using optical coherence tomography

      Seed germination rate differs based on chemical treatments, and nondestructive measurements of germination rate have become an essential requirement in the field of agriculture. Seed scientists and other biologists are interested in optical sensing technologies-based biological discoveries due to nondestructive detection capability. Optical coherence tomography (OCT) has recently emerged as a powerful method for biological and plant material discoveries. We report an extended application of OCT by monitoring the germination rate acceleration of chemically primed seeds. To validate the versatility of the method, Capsicum annum seeds were primed using three chemical compounds: sterile distilled water (SDW), butandiol, and 1-hexadecene. Monitoring ...

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    17. Noncontact three-dimensional quantitative profiling of fast aspheric lenses by optical coherence tomography

      Noncontact three-dimensional quantitative profiling of fast aspheric lenses by optical coherence tomography

      The use of optical coherence tomography (OCT) for noncontact three-dimensional aspheric lens profiling and retrieval of aspheric surface parameters is demonstrated. Two commercially available aspheric lenses with different focal length-to-diameter ratio have been imaged using OCT, and the measured optical path length distribution has been least square fitted with the aspheric lens surface retrieving the radius of curvature, aspheric constant, and conic constants. The refractive index of these lenses has also been measured referencing with a standard Zerodur glass flat. The fitted aspheric surface coefficients of the lenses are in close agreement with the manufacturer’s values, thus, envisaging the ...

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      Mentions: K. Divakar Rao
    18. Effects of spacer orientations on the cake formation during membrane fouling: Quantitative analysis based on 3D OCT imaging

      Effects of spacer orientations on the cake formation during membrane fouling: Quantitative analysis based on 3D OCT imaging

      Spacer design plays an important role in improving the performance of membrane processes for water/wastewater treatment. This work focused on a fundamental issue of spacer design, i.e., investigating the effects of spacer orientations on the fouling behavior during a membrane process. A series of fouling experiments with different spacer orientation were carried out to in situ characterize the formation of a cake layer in a spacer unit cell via 3D optical coherence tomography (OCT) imaging. The cake layers formed at different times were digitalized for quantitatively analyzing the variation in the cake morphology as a function of time ...

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    19. Contrast Enhanced Subsurface Fingerprint Detection using High-speed Optical Coherence Tomography

      Contrast Enhanced Subsurface Fingerprint Detection using High-speed Optical Coherence Tomography

      Spectral-domain optical coherence tomography (SDOCT) has been demonstrated to be a viable tool in forensic science for fingerprint detection, yet it still suffers from certain practical issues, e.g., the limited scanning speed and low image contrast. In this letter, we report a high-speed SD-OCT together with an image contrast enhancement mechanism for reliable subsurface fingerprint detection. The constructed SDOCT system achieves a scanning rate up to 60K A-lines/s, and thus, both 3D volumetric images, reaching up to 20mm × 20mm × 1.2mm, and en face internal fingerprint furrow pattern images could be obtained. Based upon the analyses of the ...

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    20. In vivo imaging of coral tissue and skeleton with optical coherence tomography

      In vivo imaging of coral tissue and skeleton with optical coherence tomography

      Optical coherence tomography (OCT) is a non-invasive three-dimensional imaging technique with micrometer resolution allowing microstructural characterization of tissues in vivo and in real time. We present the first application of OCT for in vivo imaging of tissue and skeleton structure of intact living corals spanning a variety of morphologies and tissue thickness. OCT visualized different coral tissue layers (e.g. endoderm vs ectoderm), special structures such as mesenterial filaments and skeletal cavities, as well as mucus release from living corals. We also developed a new approach for non-invasive imaging and quantification of chromatophores containing green fluorescent protein (GFP)-like host ...

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    21. Performance analysis of a Hybrid fingerprint extracted from optical coherence tomography fingertip scans

      Performance analysis of a Hybrid fingerprint extracted from optical coherence tomography fingertip scans

      The Hybrid fingerprint is a local-quality-specific blend of the surface and internal fingerprints, extracted from optical coherence tomography scans. Owing to its origin, and the manner in which it is obtained, the Hybrid fingerprint is a high-quality and secure fingerprint acquisition solution. This research entails a detailed description of the Hybrid fingerprint, the techniques involved to produce it, and a performance analysis of it. A dataset of 282 fingertip scans was established. Two recognised minutiae extraction and fingerprint matching algorithms were applied to assess the performance of the Hybrid fingerprint. The best equal error rate measured was 1.25%. NIST ...

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      Mentions: Ann Singh
    22. Fast Industrial Inspection of Optical Thin Film Using Optical Coherence Tomography

      Fast Industrial Inspection of Optical Thin Film Using Optical Coherence Tomography

      An application of spectral domain optical coherence tomography (SD-OCT) was demonstrated for a fast industrial inspection of an optical thin film panel. An optical thin film sample similar to a liquid crystal display (LCD) panel was examined. Two identical SD-OCT systems were utilized for parallel scanning of a complete sample in half time. Dual OCT inspection heads were utilized for transverse (fast) scanning, while a stable linear motorized translational stage was used for lateral (slow) scanning. The cross-sectional and volumetric images of an optical thin film sample were acquired to detect the defects in glass and other layers that are ...

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    1-24 of 208 1 2 3 4 5 6 7 8 9 »
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