1. Articles in category: Other Non-Medical

    1-24 of 244 1 2 3 4 ... 9 10 11 »
    1. 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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    2. 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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    3. 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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    4. 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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    5. 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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    6. 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
    7. 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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    8. 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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    9. 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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    10. 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
    11. 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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    12. 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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    13. 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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    14. Investigation of Puccinia triticina contagion on wheat leaves using swept source optical coherence tomography

      Investigation of Puccinia triticina contagion on wheat leaves using swept source optical coherence tomography

      We present an investigation on applicability of swept-source optical coherence tomography (SSOCT) to examine the internal structures of plant leaves. This study helps to identify the growth and spread of the leaf rust disease in leaves of wheat plants, caused by Puccinia triticina . The epidermal cell layer and parenchyma cell layer of the acquired OCT images are correlated with the histological images to show distinctive leaf morphological boundaries. In the OCT images, the thickness of the parenchyma cell layer in healthy and infected samples are compared and analyzed. Accurate morphological and quantitative information are obtained with our developed system for ...

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      Mentions: Raju Poddar
    15. Spectroscopic characterization of Si/Mo thin-film stack at extreme ultraviolet range

      Spectroscopic characterization of Si/Mo thin-film stack at extreme ultraviolet range

      A noninvasive method for characterizing Si/Mo thin-film stack thickness and its complex transfer function using common-path optical coherence tomography is proposed, analyzed, and experimentally demonstrated. A laser-produced plasma (LPP)-based extreme ultraviolet (EUV) source was excited by a four-stage nanosecond Yb:fiber laser amplifier with a pulse energy of 1.01 mJ. The tabletop LPP EUV source was compact and stable for generating the EUV interference fringes. The measured complex transfer function of the Si/Mo stack was verified near the pristine 13.5-nm wavelength range.

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    16. Evaluation of fouling in nanofiltration for desalination using a resistance-in-series model and optical coherence tomography

      Evaluation of fouling in nanofiltration for desalination using a resistance-in-series model and optical coherence tomography

      Resistance-in-series models have been applied to investigate fouling behavior. However, it is difficult to model the influence of morphology on fouling behavior because resistance is indirectly calculated from the water flux and transmembrane pressure. In this study, optical coherence tomography (OCT) was applied to evaluate the resistance of the fouling layer based on fouling morphology. Sodium alginate, humic acid, and bovine serum albumin (BSA) with high salts concentrations (conductivity: 23 mS/cm) were used as model foulants. At the same total fouling resistance, BSA showed the highest cake layer thickness (BSA (114.5 μm) > humic acid (53.5 μm) > sodium ...

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    17. In vivo automated quantification of quality of apples during storage using optical coherence tomography images

      In vivo automated quantification of quality of apples during storage using optical coherence tomography images

      Moisture content is an important feature of fruits and vegetables. As 80% of apple content is water, so decreasing the moisture content will degrade the quality of apples (Golden Delicious). The computational and texture features of the apples were extracted from optical coherence tomography (OCT) images. A support vector machine with a Gaussian kernel model was used to perform automated classification. To evaluate the quality of wax coated apples during storage in vivo , our proposed method opens up the possibility of fully automated quantitative analysis based on the morphological features of apples. Our results demonstrate that the analysis of the ...

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    18. In situ biofilm quantification in Bioelectrochemical Systems using Optical Coherence Tomography

      In situ biofilm quantification in Bioelectrochemical Systems using Optical Coherence Tomography

      Detailed studying of microbial growth in bioelectrochemical systems is required for their proper design and operation. Here we report on the use of Optical Coherence Tomography (OCT) as a tool for in situ and non‐invasive quantification of biofilm growth on electrodes (bioanodes). An experimental platform is designed and described in which transparent electrodes are used to allow for real‐time, three‐dimensional biofilm imaging. The accuracy and precision of the developed method is assessed by relating OCT results to well‐established standards for biofilm quantification (COD and Total N) and show high correspondence to these standards. Biofilm thickness as ...

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    19. Loquat Bruise Detection Using Optical Coherence Tomography Based on Microstructural Parameters

      Loquat Bruise Detection Using Optical Coherence Tomography Based on Microstructural Parameters

      Slight postharvest bruises of loquats remarkably affect the quality and shelf life of the fruits, but they are difficult to identify using visual inspection. Sub-surface structural changes in cells caused by mechanical injury or impact can be detected using spectroscopy-based methods from different angles. Optical coherence tomography (OCT), a non-destructive technology, can acquire cross-sectional images to analyze sub-surface structures of loquats, thus offering the potential to identify fruit bruises. This study proposes an automated OCT image processing method for extracting large cells from loquat images, which involves a series of steps including image denoising, boundary detection, filtering, binarization, segmentation, and ...

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    20. Detection of Latent Fingerprint Hidden Beneath Adhesive Tape by Optical Coherence Tomography

      Detection of Latent Fingerprint Hidden Beneath Adhesive Tape by Optical Coherence Tomography

      Adhesive tape is one type of common item which can be encountered in criminal cases involving rape, murder, kidnapping and explosives. It is often the case that a suspect deposits latent fingerprints on the sticky side of adhesive tape material when tying up victims, manufacturing improvised explosive devices or packaging illegal goods. However, the adhesive tapes found at crime scenes are usually stuck together or attached to a certain substrate, and thus the latent fingerprints may be hidden beneath the tapes. Current methods to detect latent fingerprint hidden beneath adhesive tape need to peel it off first and then apply ...

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    21. EXALOS Achieves a New Milestone for Next Generation Display Technologies with its First Cyan-Green Superluminescent Light Emitting Diode (SLED)

      EXALOS Achieves a New Milestone for Next Generation Display Technologies with its First Cyan-Green Superluminescent Light Emitting Diode (SLED)

      EXALOS, the world’s leading developer of visible Superluminescent Light Emitting Diodes (SLEDs), has successfully produced its first cyan-green SLED. With an output wavelength of 495 nm in between the company’s existing red (640 nm, GaAs) and blue (450 nm, GaN) devices, this SLED represents a major step toward a complete red-green-blue (RGB) SLED illumination source for micro-displays in augmented reality applications, head-up display architectures, etc. SLEDs are broadband semiconductor devices that are closely related to their more commonly known relatives, laser diodes (LDs) and light-emitting diodes (LEDs). Following the successful demonstration of blue SLEDs, Exalos embarked upon a ...

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      Mentions: Exalos
    22. Fouling development in direct contact membrane distillation: Non-invasive monitoring and destructive analysis

      Fouling development in direct contact membrane distillation: Non-invasive monitoring and destructive analysis

      Fouling development in direct contact membrane distillation (DCMD) for seawater desalination was evaluated combining in-situ monitoring performed using optical coherence tomography (OCT) together with destructive techniques. The non-invasive monitoring with OCT provided a better understanding of the fouling mechanism by giving an appropriate sampling timing for the membrane autopsy. The on-line monitoring system allowed linking the flux trend with the structure of fouling deposited on the membrane surface. The water vapor flux trend was divided in three phases based on the deposition and formation of different foulants over time. The initial flux decline was due to the deposition of a ...

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    23. Quantification of particulate matter attached to the bulk-biofilm interface and its influence on local mass transfer

      Quantification of particulate matter attached to the bulk-biofilm interface and its influence on local mass transfer

      A large fraction of the chemical oxygen demand (COD) in municipal wastewater is associated with the particulate matter. The presence of these particles might impose a negative impact on the mass transfer in biofilm systems when they attach to the bulk-biofilm interface. We thus investigated the impact of real wastewater particles by combining optical coherence tomography (OCT) and oxygen microsensor measurements. The deposition of wastewater particles of different size classes onto the biofilm surface was captured in 3D by means of OCT in a lab-scale flume. The thickness of the particle layer was calculated from OCT images. The influence of ...

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    24. Defect inspection of actuator lenses using swept-source optical coherence tomography

      Defect inspection of actuator lenses using swept-source optical coherence tomography

      Actuator lens industries have gained an enormous interest with the enhancement of various latest communication devices, such as mobile phone and notebooks. The quality of the aforementioned devices can be degraded due to the internal defects of actuator lenses. Therefore, in this study, we implemented swept-source optical coherence tomography (SS-OCT) system to inspect defects of actuator lenses. Owing to the high-resolution of the SS-OCT system, defected foreign substances between the actuator lenses, defective regions of lenses and surface stains were more clearly distinguished through three-dimensional (3D) and two-dimensional (2D) cross-sectional OCT images. Therefore, the implemented SS-OCT system can be considered ...

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