1. Articles in category: Other Non-Medical

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    1. Automated spoof-detection for fingerprints using optical coherence tomography

      Automated spoof-detection for fingerprints using optical coherence tomography

      Fingerprint recognition systems are prevalent in high-security applications. As a result, the act of spoofing these systems with artificial fingerprints is of increasing concern. This research presents an automatic means for spoof-detection using optical coherence tomography (OCT). This technology is able to capture a 3D representation of the internal structure of the skin and is thus not limited to a 2D surface scan. The additional information afforded by this representation means that accurate spoof-detection can be achieved. Two features were extracted to detect the presence of (1) an additional thin layer on the surface of the skin and (2) a ...

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    2. Optical coherence elastography for human finger-pad skin deformation studies

      Optical coherence elastography for human finger-pad skin deformation studies

      An optical coherence tomography (OCT) system with an A-scan rate of 20 kHz was developed for measuring the biomechanical properties of human finger-pad skin. Such an OCT system operates at a center wavelength of 890 nm with a spectral bandwidth of 150 nm resulting in a very good axial resolution of 2.6 μm. The measured sensitivity and sensitivity roll-off of the system were ~93 dB and ~6 dB mm -1 , respectively. Elastographic B-scan images of the human finger-pad skin were constructed by using 1000 A-scans. Deformations of the human finger-pad before and after sliding, while pressed against a transparent ...

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    3. Response of simulated drinking water biofilm mechanical and structural properties to long-term disinfectant exposure

      Response of simulated drinking water biofilm mechanical and structural properties to long-term disinfectant exposure

      Mechanical and structural properties of biofilms influence the accumulation and release of pathogens in drinking water distribution systems (DWDS). Thus, understanding how long-term residual disinfectants exposure affects biofilm mechanical and structural properties is a necessary aspect for pathogen risk assessment and control. In this study, elastic modulus and structure of groundwater biofilms was monitored by atomic force microscopy (AFM) and optical coherence tomography (OCT) during three months of exposure to monochloramine or free chlorine. After the first month of disinfectant exposure, the mean stiffness of monochloramine or free chlorine treated biofilms was 4 to 9 times higher than those before ...

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    4. The Application of Full-Field Optical Coherence Tomography on Evaluating Film Coating of Pharmaceutical Pellets

      The Application of Full-Field Optical Coherence Tomography on Evaluating Film Coating of Pharmaceutical Pellets

      This paper focuses on the application of full-field optical coherence tomography (FF-OCT) imaging on quantifying coating thickness and characterizing coating structures of two layer pharmaceutical pellets. This FF-OCT system used aninexpensive infrared light-emitting diode (LED) as the opticalsource and a commercial high speed complementary metal-oxidesemiconductor (CMOS) camera as the detector. A total volume of700 × 50 × 200 μm3 (x-y-z) were imaged by using the FF-OCTdevice. A high spatial resolution of 4.0 × 5.0 μm2 (axial × lateral)was achieved. In the cross-sectional image the internal structuredetails can be clearly observed and in particular particle-likefeatures can be clearly ...

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    5. Fingerprint Matching with Optical Coherence Tomography

      Fingerprint Matching with Optical Coherence Tomography

      Fingerprint recognition is an important security technique with a steadily growing usage for the identification and verification of individuals. However, current fingerprint acquisition systems have certain disadvantages, which include the requirements of physical contact with the acquisition device, and the presence of undesirable artefacts, such as scars, on the surface of the fingerprint. This paper evaluates the accuracy of a complete framework for the capturing of undamaged, undistorted fingerprints from below the skins surface using optical coherence tomography hardware, the extraction and conversion of the subsurface data into a usable fingerprint and the matching of such fingerprints. The ability of ...

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    6. Study on internal to surface fingerprint correlation using optical coherence tomography and internal fingerprint extraction

      Study on internal to surface fingerprint correlation using optical coherence tomography and internal fingerprint extraction

      Surface fingerprint scanners are limited to a two-dimensional representation of the fingerprint topography, and thus, are vulnerable to fingerprint damage, distortion, and counterfeiting. Optical coherence tomography (OCT) scanners are able to image (in three dimensions) the internal structure of the fingertip skin. Techniques for obtaining the internal fingerprint from OCT scans have since been developed. This research presents an internal fingerprint extraction algorithm designed to extract high-quality internal fingerprints from touchless OCT fingertip scans. Furthermore, it serves as a correlation study between surface and internal fingerprints. Provided the scanned region contains sufficient fingerprint information, correlation to the surface topography is ...

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    7. BitFlow plays crucial role in new fingerprint imaging system design

      BitFlow plays crucial role in new fingerprint imaging system design

      - BitFlow, Inc. announced that it designed a key component of a new fingerprint imaging system that can look underneath the finger’s skin to identify an individual quickly and accurately. The fingerprint system was engineered by two scientists from The Langevin Institute in Paris. Egidijus Auksorius, postdoctoral researcher, and Claude Boccara, a professor who specializes in scientific instruments. The system captures “ internal fingerprints ” which share the same topographical features as external fingerprints, but are about half a millimeter below the skin’s surface. The machine can also capture image sweat pores, which provides additional means of identification. The fingerprint imaging ...

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    8. This innovative fingerprint scanner can discern fake fingerprints from real ones

      This innovative fingerprint scanner can discern fake fingerprints from real ones

      Beware evil villains and career crooks, the machine vision technology company BitFlow just developed a revolutionary fingerprint scanner capable of discerning fake fingerprints from real ones. Whereas typical fingerprint scanners are fairly simple to fool , BitFlow’s new tech scraps the traditional process of photo scanning in favor of a method which actually looks inside a person’s finger. Time to throw out all that Play-Doh you had reserved for shady fingerprint forgery. Developed in conjunction with scientists at the Langevin Institute in Paris, France, the innovative new scanner quickly and accurately captures, what the team calls, a person’s ...

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    9. Assessing the influence of biofilm surface roughness on mass transfer by combining optical coherence tomography and two-dimensional modeling

      Assessing the influence of biofilm surface roughness on mass transfer by combining optical coherence tomography and two-dimensional modeling

      Imaging and modeling are two major approaches in biofilm research to understand the physical and biochemical processes involved in biofilm development. However, they are often used separately. In this study we combined these two approaches to investigate substrate mass transfer and mass flux. Cross-sectional biofilm images were acquired by means of optical coherence tomography (OCT) for biofilms grown on carriers. A 2D biofilm model was developed incorporating OCT images as well as a simplified biofilm geometry serving as structural templates. The model incorporated fluid flow, substrate transfer and biochemical conversion of substrates and simulated the hydrodynamics surrounding the biofilm structure ...

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    10. Live Acquisition of Internal Fingerprint with Automated Detection of Subsurface Layers Using OCT

      Live Acquisition of Internal Fingerprint with Automated Detection of Subsurface Layers Using OCT

      Recently, optical coherence tomography (OCT) was introduced as a novel fingerprint scanning technique. This approach is resistant to fake fingerprint attacks, and is robust against poor fingertip conditions – i.e., wet or stained fingers. The method proceeds by scanning a fingertip in three dimensions and capturing a fingerprint from the subsurface layer. Although OCT has the potential to be widely used as a new standard in fingerprint scanning, it is hindered by its low scanning speed and the lack of computing power available for reproducing raw OCT data into images in real-time; for instance, this process can take minutes to ...

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      Mentions: Korea University
    11. Efficient internal and surface fingerprint extraction and blending using optical coherence tomography

      Efficient internal and surface fingerprint extraction and blending using optical coherence tomography

      Optical coherence tomography provides a 3D representation of fingertip skin where surface and internal fingerprints are found. These fingerprints are topographically identical. However, the surface skin is prone to damage, distortion, and spoofing; and the internal fingerprint is difficult to access and extract. This research presents a novel scaling-resolution approach to fingerprint zone detection and extraction. Furthermore, a local-quality-based blending procedure is also proposed. The accuracy of the zone-detection algorithm is comparable to an earlier work, yielding a mean-squared error of 25.9 and structural similarity of 95.8% (compared to a ground-truth estimate). Blending the surface and internal fingerprints ...

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    12. Photonic Imaging with Optical Coherence Tomography for Quality Monitoring in the Poultry Industry: a Preliminary Study

      Photonic Imaging with Optical Coherence Tomography for Quality Monitoring in the Poultry Industry: a Preliminary Study

      A photonic imaging method that gives the possibility to measure egg quality was applied. Since the method is non-contact and non-destructive we believe that this photonic imaging method may be successfully integrated in the automated inspection systems in the poultry industry. The method involves scanning an invisible infrared light beam over the eggshell, allowing to detect possible cracks and reveal information about the structure of the eggshell. The high resolution, high quality measurements obtained through optical coherence tomography (OCT) make it feasible to be utilized as part of an automated inspection system. In this paper we present an OCT scan ...

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    13. Non-destructive cross-sectional imaging of tomato using ultra-high resolution optical coherence tomography

      Non-destructive cross-sectional imaging of tomato using ultra-high resolution optical coherence tomography

      Optical coherence tomography is an optical imaging technique that performs non-destructive cross-sectional imaging of micrometer-scale structures in samples. In this report, we demonstrated the visualization of inner structures in tomato fruits and leaves with ultra-high resolution optical coherence tomography (UHR-OCT) using fiber based laser source with ultra-broadband continuous spectrum around 1.7 μm wavelength. We confirmed that our UHR-OCT system allows us to perform cross-sectional imaging of tomato fruits and leaves at ∼ 2.8 μm axial resolution.

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    14. Characterising kiwifruit (Actinidia sp.) near skin cellular structures using optical coherence tomography

      Characterising kiwifruit (Actinidia sp.) near skin cellular structures using optical coherence tomography

      Pre-harvest growing conditions during the development of fruit have impacts on fruit quality at the time of harvest and during storage. These impacts may result in differences in the skin properties of the fruit and some sub-surface cellular structural changes, which have potential effects on postharvest fruit quality and storability. Optical coherence tomography (OCT) is a non-destructive imaging method that enables acquisition of three-dimensional (3D) images of sub-surface structures of semi-transparent and turbid objects. This technology is a potential tool to provide new information about the structural nature of horticulture products. This work used five commercial kiwifruit cultivars, ‘G3’, ‘G9 ...

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    15. Optical coherence tomography for the in situ three-dimensional visualization and quantification of feed spacer channel fouling in reverse osmosis membrane modules

      Optical coherence tomography for the in situ three-dimensional visualization and quantification of feed spacer channel fouling in reverse osmosis membrane modules

      To understand the (bio)fouling development in membrane modules in more detail, three-dimensional in situ imaging of the feed spacer channel by means of optical coherence tomography (OCT) was applied. The biofilm formation was investigated in membrane fouling simulators (MFS) mimicking the feed spacer channel of spiral wound reverse osmosis membrane modules. To test the capability of OCT for the visualization of feed spacer fouling, river water and effluent of a waste water treatment plant were used as feeds. Additionally, the (bio)fouling characteristics of a wide-meshed and small-meshed feed spacer were tested. 3D OCT datasets were quantified and the ...

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    16. Accurate velocity measurements of boundary-layer flows using Doppler optical coherence tomography

      Accurate velocity measurements of boundary-layer flows using Doppler optical coherence tomography

      Pulsed ultrasound Doppler velocimetry and nuclear magnetic resonance imaging are popular non-invasive measurement methods for flows of opaque fluids. The spatial and temporal resolution of these methods, however, is quite limited, and they lack accuracy, especially close to solid boundaries. In this paper, we show that solution to these problems is achieved by using Doppler optical coherence tomography (DOCT). DOCT provides simultaneous information about the fluid structure and velocity with very high spatial and temporal resolution. For benchmarking of the method we use water as the reference fluid. We show how DOCT gives a very good agreement with theory for ...

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    17. Internal fingerprint acquisition from optical coherence tomography fingertip scans

      Internal fingerprint acquisition from optical coherence tomography fingertip scans

      Current surface fingerprint scanners measure the surface topography of skin, resulting in vulnerabilities to surface skin erosion, distortion due to contact with the scanner, and fingerprint counterfeiting. An improved means of fingerprint acquisition is necessitated in these facts. By employing an imaging technique known as Optical Coherence Tomography to the human fingertip skin, a three-dimensional digital reconstruction of subsurface layers of skin can be used for the extraction of an internal fingerprint. The internal fingerprint is robust towards counterfeiting, damage, and distortion, thus providing a replacement for the surface fingerprint. However, OCT scans are corrupted by speckle noise and have ...

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    18. Internal fingerprint zone detection in optical coherence tomography fingertip scans

      Internal fingerprint zone detection in optical coherence tomography fingertip scans

      Optical coherence tomography (OCT) is a high-resolution imaging technology capable of capturing a three-dimensional (3-D) representation of fingertip skin. The papillary junction—a junction layer of skin containing the same topographical features as the surface fingerprint—is contained within this representation. The top edge of the papillary junction contains the topographical information pertinent to the internal fingerprint. Extracting the internal fingerprint from OCT fingertip scans has been shown to be possible. Currently, acquiring the internal fingerprint involves manually defining the region containing it. This manner of definition is inefficient. Perfect knowledge of the location of the papillary junction is hypothesized ...

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    19. Six-dimensional Optical Multilayer Storage Using Two-photon Absorption Writing, Erasing and Optical Coherence Tomography Reading

      Six-dimensional Optical Multilayer Storage Using Two-photon Absorption Writing, Erasing and Optical Coherence Tomography Reading

      This invention relates a method of six-dimensional optical multilayer storage using two-photon absorption writing, erasing and optical coherence tomography reading and the apparatus designed based on this method. The invented system stores data in three spatial dimensions plus three physical dimensions of wavelength, intensity and polarization.

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    20. Visualization of dynamic boiling processes using high-speed optical coherence tomography

      Visualization of dynamic boiling processes using high-speed optical coherence tomography

      Investigating microscale nucleate boiling processes with high heat flux requires experimental visualization and quantification with high spatial resolution in the micrometer range as well as a sufficient temporal resolution. Numerous measurement techniques are employed for providing comprehensive experimental data on microscale boiling processes and other multiphase flows. In this context, optical coherence tomography (OCT) has been introduced recently for the visualization of quasistatic growing vapor bubbles in turbid fluids with a high spatial resolution. Since OCT detects backscattered light, only one optical access is necessary and OCT is feasible for measurements in turbid media, where other imaging techniques fail. Within ...

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    21. A review of state-of-the-art speckle reduction techniques for optical coherence tomography fingertip scans

      A review of state-of-the-art speckle reduction techniques for optical coherence tomography fingertip scans

      Standard surface fingerprint scanners are vulnerable to counterfeiting attacks and also failure due to skin damage and distortion. Thus a high security and damage resistant means of fingerprint acquisition is needed, providing scope for new approaches and technologies. Optical Coherence Tomography (OCT) is a high resolution imaging technology that can be used to image the human fingertip and allow for the extraction of a subsurface fingerprint. Being robust toward spoofing and damage, the subsurface fingerprint is an attractive solution. However, the nature of the OCT scanning process induces speckle: a correlative and multiplicative noise. Six speckle reducing filters for the ...

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    22. Tomographic Inspection of Fiber Coils Using Optical Coherence Tomography

      Tomographic Inspection of Fiber Coils Using Optical Coherence Tomography

      We report the first study of using optical coherence tomography (OCT) to inspect the winding quality of fiber optical gyro coils. We use a swept-source OCT system to scan a quadrupole-wind fiber coil for obtaining its two-dimensional and three-dimensional (3D) tomographic images. The defects beneath the surface of the fiber coil, which otherwise are invisible by video inspection, can be clearly identified with such tomographic images. The winding quality of each layer can also be independently visualized with the reconstructed 3D images from different angles or in different sections. We believe that the proposed method will be useful to ensuring ...

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    23. Extracting subsurface fingerprints using Optical Coherence Tomography

      Extracting subsurface fingerprints using Optical Coherence Tomography

      Physiologists have found that fingerprint patterns exist in the inner layers (viz. papillary junction) of the skin of the fingertip. However, conventional acquisition systems do not have capabilities to extract fingerprints at subsurface layers of the finger for use in identity authentication. The subsurface fingerprint representation is of a higher quality than the surface representation as it does not contain deformations such as creases or scars which may be present on the surface of the fingertip. This paper presents a novel approach to extract the subsurface fingerprint representation using a high-resolution imaging technology known as Optical Coherence Tomography (OCT).

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    24. Gravity-driven membrane filtration as pretreatment for seawater reverse osmosis: Linking biofouling layer morphology with flux stabilization

      Gravity-driven membrane filtration as pretreatment for seawater reverse osmosis: Linking biofouling layer morphology with flux stabilization

      In this study gravity-driven membrane (GDM) ultrafiltration is investigated for the pretreatment of seawater before reverse osmosis (RO). The impacts of temperature (21 ± 1 and 29 ± 1 °C) and hydrostatic pressure (40 and 100 mbar) on dynamic flux development and biofouling layer structure were studied. The data suggested pore constriction fouling was predominant at the early stage of filtration, during which the hydrostatic pressure and temperature had negligible effects on permeate flux. With extended filtration time, cake layer fouling played a major role, during which higher hydrostatic pressure and temperature improved permeate flux. The permeate flux stabilized in a range ...

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    1-24 of 171 1 2 3 4 5 6 7 8 »
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