1. Articles in category: NDE/NDT

    1-24 of 261 1 2 3 4 ... 9 10 11 »
    1. 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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    2. 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
    3. Measurement of the inter-tablet coating uniformity of a pharmaceutical pan coating process with combined terahertz and optical coherence tomography in-line sensing

      Measurement of the inter-tablet coating uniformity of a pharmaceutical pan coating process with combined terahertz and optical coherence tomography in-line sensing

      We present in-line coating thickness measurements acquired simultaneously using two independent sensing modalities: terahertz pulsed imaging (TPI) and optical coherence tomography (OCT). Both techniques are sufficiently fast to resolve the coating thickness of individual pharmaceutical tablets in-situ during the film coating operation and both techniques are direct structural imaging techniques that do not require multivariate calibration. The TPI sensor is suitable to measure coatings greater than 50 μm and can penetrate through thick coatings even in the presence of pigments over a wide range of excipients. Due to the long wavelength, terahertz radiation is not affected by scattering from dust ...

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    4. 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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    5. Non-invasive method and apparatus for screening high-quality seeds

      Non-invasive method and apparatus for screening high-quality seeds

      Disclosed is a method and apparatus for the non-invasive selection of high-quality seeds, based on optical coherence tomography, by which pathogen-infected and pathogen-free seeds can be discriminated in a non-invasive manner. The apparatus is operated by the processes of scanning a seed of diagnostic interest in a non-invasive manner using an optical coherence tomographic unit; processing interference signals of the scanned tomographic images to produce tomographic image data of the seed of diagnostic interest; analyzing the tomographic image data; comparing the analyzed tomographic image data with preset reference tomographic image data; diagnosing the seed of diagnostic interest as a pathogen-infected ...

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    6. Investigating Intra-Tablet Coating Uniformity With Spectral-Domain Optical Coherence Tomography

      Investigating Intra-Tablet Coating Uniformity With Spectral-Domain Optical Coherence Tomography

      Spectral domain optical coherence tomography (SD-OCT) has recently attracted a lot of interest in the pharmaceutical industry as a fast and non-destructive modality for direct quantification of thin film coatings that cannot easily be resolved with other techniques. While previous studies with SD-OCT have estimated the intra-tablet coating uniformity, the estimates were based on limited number of B-scans. In order to obtain a more accurate estimate, a greater number of B-scans are required that can quickly lead to an overwhelming amount of data. To better manage the data so as to generate a more accurate representation of the intra-tablet coating ...

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    7. 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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    8. Automated Internal Classification of Beadless Chinese ZhuJi Fleshwater Pearls based on Optical Coherence Tomography Images

      Automated Internal Classification of Beadless Chinese ZhuJi Fleshwater Pearls based on Optical Coherence Tomography Images

      Optical coherence tomography (OCT) has been applied to inspect the internal defect of beadless Chinese ZhuJi fleshwater pearls. A novel fully automated algorithm is proposed to classify between normal and defective sub-layer in nacre layer. Our algorithm utilizes the graph segmentation approach to estimate the up and down boundaries of defect sub-layers from flattened and cropped image, and also proposes the strategy for edge and weight construction in segmentation process. The vertical gradients of boundary pixels are used to make grading decision. The algorithm is tested by typical pearl samples, and achieves 100% classification accuracy. The experiment result shows the ...

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    9. 1310 nm Source Spectral-Domain Optical Coherence Tomography for Chinese Pigment and Jadeite Research

      1310 nm Source Spectral-Domain Optical Coherence Tomography for Chinese Pigment and Jadeite Research

      Optical Coherence Tomography (OCT) technique is a nondestructive optical detection technology based on low-coherence interferometer and it has become an attractive cultural heritage research method. A 1310 nm source spectral-domain optical coherence tomography (SD-OCT) system based on optical fiber Michelson interferometer and optical spectrum analyzer is proposed and demonstrated for Chinese cultural heritage research. The cross-section OCT images of Chinese pigment samples and jadeite samples can provide a lot of valuable

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    10. 3rd International Symposium on Optical Coherence Tomography for Non-Destructive Testing Linz Austria

      3rd International Symposium on Optical Coherence Tomography for Non-Destructive Testing Linz Austria

      3rd International Symposium on Optical Coherence Tomography for Non-Destructive Testing The symposium takes place on February 15 th - 16 th , 2017 at the Johannes Kepler University in Linz, Austria . The symposium is dedicated to present the latest scientific results, methodological and technological advancements related to optical coherence tomography in the field of non-destructive testing. It is intended as a get-together for people working in this field and aims at initiating new ideas and projects. Researchers from academia and industry are invited to participate and exchange their knowledge on optical coherence tomography. The accompanying exhibition provides an excellent contact platform and ...

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    11. Non-Destructive Art Inspection Using SWIR and Terahertz Spectroscopy

      Non-Destructive Art Inspection Using SWIR and Terahertz Spectroscopy

      Conclusion Cultural Heritage Traditionally, artists painted canvas, paper, parchment, wood, walls, and ceramics to produce images of their own intuition and to depict their contemporaries. This artform is still in use by the current generation of artists. Over the centuries artists have left valuable art works that should withstand the test of times.

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      Mentions: Xenics
    12. Multiscale dispersion-state characterization of nanocomposites using optical coherence tomography

      Multiscale dispersion-state characterization of nanocomposites using optical coherence tomography

      Nanocomposite materials represent a success story of nanotechnology. However, development of nanomaterial fabrication still suffers from the lack of adequate analysis tools. In particular, achieving and maintaining well-dispersed particle distributions is a key challenge, both in material development and industrial production. Conventional methods like optical or electron microscopy need laborious, costly sample preparation and do not permit fast extraction of nanoscale structural information from statistically relevant sample volumes. Here we show that optical coherence tomography (OCT) represents a versatile tool for nanomaterial characterization, both in a laboratory and in a production environment. The technique does not require sample preparation and ...

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    13. A 45° saw-dicing process applied to a glass substrate for wafer-level optical splitter fabrication for optical coherence tomography

      A 45° saw-dicing process applied to a glass substrate for wafer-level optical splitter fabrication for optical coherence tomography

      This paper reports on the development of a technology for the wafer-level fabrication of an optical Michelson interferometer, which is an essential component in a micro opto-electromechanical system (MOEMS) for a miniaturized optical coherence tomography (OCT) system. The MOEMS consists on a titanium dioxide/silicon dioxide dielectric beam splitter and chromium/gold micro-mirrors. These optical components are deposited on 45° tilted surfaces to allow the horizontal/vertical separation of the incident beam in the final micro-integrated system. The fabrication process consists of 45° saw dicing of a glass substrate and the subsequent deposition of dielectric multilayers and metal layers. The ...

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    14. High-resolution and nondestructive profile measurement by spectral-domain optical coherence tomography with a visible broadband light source for optical-device fabrication

      High-resolution and nondestructive profile measurement by spectral-domain optical coherence tomography with a visible broadband light source for optical-device fabrication

      We developed a spectral-domain optical coherence tomography (OCT) using a visible broadband light source (vis-OCT) for application to high-resolution and nondestructive profile measurement and imaging in semiconductor optical-device fabrication. By using visible broadband light centered at 625 nm and with spectral bandwidth of 260 nm, an axial resolution of 0.69 µm in air was obtained. This was effective for inspection of a transparent photoresist film with thickness of 1–2 µm coated on a semiconductor wafer; the interface between the photoresist film and its substrate and the interface between the photoresist and air were resolved, and the film thickness ...

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    15. Loose powder detection and surface characterization in selective laser sintering via optical coherence tomography

      Loose powder detection and surface characterization in selective laser sintering via optical coherence tomography

      Defects produced during selective laser sintering (SLS) are difficult to non-destructively detect after build completion without the use of X-ray-based methods. Overcoming this issue by assessing integrity on a layer-by-layer basis has become an area of significant interest for users of SLS apparatus. Optical coherence tomography (OCT) is used in this study to detect surface texture and sub-surface powder, which is un-melted/insufficiently sintered, is known to be a common cause of poor part integrity and would prevent the use of SLS where applications dictate assurance of defect-free parts. To demonstrate the capability of the instrument and associated data-processing algorithms ...

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    16. MIT’s 10-Material 3D Printer Heading to Production?

      MIT’s 10-Material 3D Printer Heading to Production?

      In 2015, MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) reported news that the lab had developed a unique multimaterial 3D printer capable of combining 10 different materials and integrating complex components, such as sensors and circuits, during the printing process. Perhaps most exciting was the fact that the system required only $7,000 in parts to build. Now, a bit of news has come across the wire indicating that MIT CSAIL’s MultiFab 3D printer may be going into production. he MultiFab 3D printer fabricates objects by jetting up to 10 different photopolymers through piezoelectric inkjet printheads, which ...

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    17. Characterization of Automotive Paint by Optical Coherence Tomography

      Characterization of Automotive Paint by Optical Coherence Tomography

      Automotive paint is a common trace evidence that plays a significant role in many vehicle-related criminal cases. However, the conventional methods of obtaining tomographic images tend to damage the samples. Optical coherence tomography (OCT) is a novel method to obtain high-resolution, and cross-sectional images of the automotive paints in a non-destructive, and high-speed manner. In this study, OCT was applied to image and analyze the automotive paint, using Scanning Electron Microscope (SEM) as reference. Eight automotive paint samples of different brands were examined. The images of multi-layer structures provided by OCT system with 5 μm depth resolution were consistent with ...

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    18. Optical teardown of a Kindle Paperwhite display by OCT.

      Optical teardown of a Kindle Paperwhite display by OCT.

      An optical teardown, or reverse engineering, of an Amazon Kindle Paperwhite electrophoretic display was performed by Optical Coherence Tomography at 1060 nm. The display incorporates an optical diffuser, lightguide and scattering layers for white light illumination, capacitive touch sensing, and an electrophoretic display. All these layers can be imaged by OCT as well as the thin film transistor array on the back side for driving the pixels. Phase sensitive OCT is used to measure motion of the pigment particles as the display changes between black and white.

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    19. Nondestructive Analysis of Jingdezhen and Longquan Celadon Wares Excavated from Nanhai No.1 Shipwreck

      Nondestructive Analysis of Jingdezhen and Longquan Celadon Wares Excavated from Nanhai No.1 Shipwreck

      The provenance study of ancient ceramics, as an important part in archaeological field, is the researching focus for researchers in scientific and technological archaeology. At present, the provenance study of ancient ceramics mainly depends on chemical analysis technologies while non-destructive physical structural analysis of ceramic glaze is relatively lacking. Therefore, it is difficult to have a comprehensive understanding of ancient ceramics. Optical coherence tomography (OCT) is an emerging non-destructive imaging technology with a high sensitivity. In this paper, the OCT combined with X-ray fluorescence spectroscopy (XRF) is employed firstly to analyze celadon wares of Jingdezhen and Longquan found in Nanhai ...

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    20. Nondestructive analysis of automotive paints with spectral domain optical coherence tomography

      Nondestructive analysis of automotive paints with spectral domain optical coherence tomography

      We have demonstrated for the first time, to our knowledge, the use of optical coherence tomography (OCT) as an analytical tool for nondestructively characterizing the individual paint layer thickness of multiple layered automotive paints. A graph-based segmentation method was used for automatic analysis of the thickness distribution for the top layers of solid color paints. The thicknesses measured with OCT were in good agreement with the optical microscope and ultrasonic techniques that are the current standard in the automobile industry. Because of its high axial resolution (5.5 μm), the OCT technique was shown to be able to resolve the ...

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      Mentions: Yalin Zheng
    21. Towards in-situ process monitoring in selective laser sintering using optical coherence tomography

      Towards in-situ process monitoring in selective laser sintering using optical coherence tomography

      Selective laser sintering (SLS) enables fast, flexible and cost-efficient production of parts directly from 3D CAD data. However, compared with more established machine tools, there is a marked lack of process monitoring and feedback control of key process variables to optimize production parameters in-situ. We apply optical coherence tomography (OCT) to evaluate components produced by SLS and suggest a route for its application in in-situ process monitoring within the SLS tool for real-time monitoring of the SLS process for assurance, or even dynamic correction of defects during the build. OCT is shown to be a viable technique for evaluation of ...

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    22. Handheld non-contact evaluation of fastener flushness and countersink surface profiles using optical coherence tomography

      Handheld non-contact evaluation of fastener flushness and countersink surface profiles using optical coherence tomography

      We report the use of spectral domain optical coherence tomography (SD-OCT) for non-contact optical evaluation of fastener flushness and countersink surface profile. Using a handheld galvanometer scanner of only 0.5 lb in weight the SD-OCT can perform line scan surface profile measurement of fastener and countersink without demanding accurate scan center alignment. It demonstrates fast measurement of fastener flushness, radius, slant angle, as well as countersink edge radius and surface angle within 90 ms suitable for handheld operation. With the use of a broadband light source at 840 nm center wavelength and 45 nm spectral bandwidth and a lens ...

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    23. Interferometric system based on swept source-optical coherence tomography scheme applied to the measurement of distances of industrial interest

      Interferometric system based on swept source-optical coherence tomography scheme applied to the measurement of distances of industrial interest

      We used an interferometric technique based on typical optical coherence tomography (OCT) schemes for measuring distances of industrial interest. The system employed as a light source a tunable erbium-doped fiber laser of ∼ 20 - pm ∼20-pm bandwidth with a tuning range between 1520 and 1570 nm. It has a sufficiently long coherence length to enable long depth range imaging. A set of fiber Bragg gratings was used as a self-calibration method, which has the advantage of being a passive system that requires no additional electronic devices. The proposed configuration and the coherence length of the laser enlarge the range of maximum ...

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    24. Development of spectral domain optical coherence tomography for pharmaceutical and medical application

      Development of spectral domain optical coherence tomography for pharmaceutical and medical application

      Spectral-domain optical coherence tomography (SD-OCT) is a type of non-destructive imaging technique that is capable of resolving the inner structure of a sample with micrometre spatial resolution. SD-OCT is based on low coherence interferometry. It utilises a spectrometer to grab the spectral interferogram between the back reflected/scattered light from a reference mirror and a sample. The depth profile, which carries the sample inner structure information, is then generated by a data interpolation and Fourier Transform (FT). Functional coating of solid oral dosage forms optimises the release profile of active pharmaceutical ingredient (API) and results in a desirable API absorption ...

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    1-24 of 261 1 2 3 4 ... 9 10 11 »
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