WorldWideScience

Sample records for fluorescence laser scanning

  1. GFP fluorescence imaging with laser confocal scanning microscope

    Science.gov (United States)

    Yu, Yanhua; Xing, Da; Shi, Qiaojuan; Zhou, Junchu

    1999-09-01

    With gene marking technique, green fluorescent protein (GFP) and nodule bacteria gene has been linked together to form a single fusion gene expression vector. Then the vector is transferred into the nodule bacteria and the astragalus sinicus is invaded by the vector. With laser confocal scanning microscope, some important morphological information in plant nitrogen fixation research about the invading of nodule bacteria and the formation process of root nodule has been obtained through the 3D imaging of GFP reporting fluorescence.

  2. Clinical applications of in vivo fluorescence confocal laser scanning microscopy

    Science.gov (United States)

    Oh, Chilhwan; Park, Sangyong; Kim, Junhyung; Ha, Seunghan; Park, Gyuman; Lee, Gunwoo; Lee, Onseok; Chun, Byungseon; Gweon, Daegab

    2008-02-01

    Living skin for basic and clinical research can be evaluated by Confocal Laser Scanning Microscope (CLSM) non-invasively. CLSM imaging system can achieve skin image its native state either "in vivo" or "fresh biopsy (ex vivo)" without fixation, sectioning and staining that is necessary for routine histology. This study examines the potential fluorescent CLSM with a various exogenous fluorescent contrast agent, to provide with more resolution images in skin. In addition, in vivo fluorescent CLSM researchers will be extended a range of potential clinical application. The prototype of our CLSM system has been developed by Prof. Gweon's group. The operating parameters are composed of some units, such as illuminated wavelength 488 nm, argon illumination power up to 20mW on the skin, objective lens, 0.9NA oil immersion, axial resolution 1.0μm, field of view 200μm x 100μm (lateral resolution , 0.3μm). In human volunteer, fluorescein sodium was administrated topically and intradermally. Animal studies were done in GFP transgenic mouse, IRC mouse and pig skin. For imaging of animal skin, fluorescein sodium, acridine orange, and curcumine were used for fluorescein contrast agent. We also used the GFP transgenic mouse for fluorescein CLSM imaging. In intact skin, absorption of fluorescein sodium by individual corneocyte and hair. Intradermal administrated the fluorescein sodium, distinct outline of keratinocyte cell border could be seen. Curcumin is a yellow food dye that has similar fluorescent properties to fluorescein sodium. Acridin Orange can be highlight nuclei in viable keratinocyte. In vivo CLSM of transgenic GFP mouse enable on in vivo, high resolution view of GFP expressing skin tissue. GFP signals are brightest in corneocyte, kertinocyte, hair and eccrine gland. In intact skin, absorption of fluorescein sodium by individual corneocyte and hair. Intradermal administrated the fluorescein sodium, distinct outline of keratinocyte cell border could be seen. In

  3. Laser scanning endoscope via an imaging fiber bundle for fluorescence imaging

    Science.gov (United States)

    Yeboah, Lorenz D.; Nestler, Dirk; Steiner, Rudolf W.

    1994-12-01

    Based on a laser scanning endoscope via an imaging fiber bundle, a new approach for a tumor diagnostic system has been developed to assist physicians in the diagnosis before the actual PDT is carried out. Laser induced, spatially resolved fluorescence images of diseased tissue can be compared with images received by video endoscopy using a white light source. The set- up is required to produce a better contrast between infected and healthy tissue and might serve as a constructive diagnostic help for surgeons. The fundamental idea is to scan a low-power laser beam on an imaging fiber bundle and to achieve a spatially resolved projection on the tissue surface. A sufficiently high laser intensity from the diode laser is concentrated on each single spot of the tissue exciting fluorescence when a dye has previously been accumulated. Subsequently, video image of the tissue is recorded and stored. With an image processing unit, video and fluorescence images are overlaid producing a picture of the fluorescence intensity in the environment of the observed tissue.

  4. Fluorescence confocal laser scanning microscopy for in vivo imaging of epidermal reactions to two experimental irritants

    DEFF Research Database (Denmark)

    Suihko, C.; Serup, J.

    2008-01-01

    Background: Fibre-optic fluorescence confocal laser scanning microscopy (CLSM) is a novel non-invasive technique for in vivo imaging of skin. The cellular structure of the epidermis can be studied. A fluorophore, e.g. fluorescein sodium, is introduced by an intradermal injection or applied...... to the skin surface before scanning. Images are horizontal optical sections parallel to the skin surface. Fluorescence CLSM has hitherto not been applied to experimental contact dermatitis. Objective: The aim was to study the applicability of fluorescence CLSM for in situ imaging of irritant contact......, modified the physico-chemical properties of the skin surface and both disturbed epicutaneous labelling with the flurophore and immersion oil coupling between the skin surface and the optical system. Thus, SLS was technically more difficult to study by CLSM than PA. Conclusions: This preliminary study...

  5. Fluorescence confocal laser scanning microscopy for in vivo imaging of epidermal reactions to two experimental irritants

    DEFF Research Database (Denmark)

    Suihko, C.; Serup, J.

    2008-01-01

    Background: Fibre-optic fluorescence confocal laser scanning microscopy (CLSM) is a novel non-invasive technique for in vivo imaging of skin. The cellular structure of the epidermis can be studied. A fluorophore, e.g. fluorescein sodium, is introduced by an intradermal injection or applied...... dermatitis reactions caused by established model irritants, e.g. sodium lauryl sulphate (SLS) and pelargonic acid (PA). Methods: Twelve healthy individuals volunteered. The flexor aspect of the right and the left forearm was exposed to SLS in water and PA in isopropanol and occluded under Finn Chambers...... for 24 h. The reactions were rated clinically and, following epicutaneous and intra-dermal application of fluorescein sodium, studied by fluorescence CLSM, magnification x 1000. Results: Both irritants disturbed the epidermal intercellular borders, which became blurred, thickened and variably altered...

  6. Thermal maturity of Tasmanites microfossils from confocal laser scanning fluorescence microscopy

    Science.gov (United States)

    Hackley, Paul C.; Kus, Jolanta

    2015-01-01

    We report here, for the first time, spectral properties of Tasmanites microfossils determined by confocal laser scanning fluorescence microscopy (CLSM, using Ar 458 nm excitation). The Tasmanites occur in a well-characterized natural maturation sequence (Ro 0.48–0.74%) of Devonian shale (n = 3 samples) from the Appalachian Basin. Spectral property λmax shows excellent agreement (r2 = 0.99) with extant spectra from interlaboratory studies which used conventional fluorescence microscopy techniques. This result suggests spectral measurements from CLSM can be used to infer thermal maturity of fluorescent organic materials in geologic samples. Spectra of regions with high fluorescence intensity at fold apices and flanks in individual Tasmanites are blue-shifted relative to less-deformed areas in the same body that have lower fluorescence intensity. This is interpreted to result from decreased quenching moiety concentration at these locations, and indicates caution is needed in the selection of measurement regions in conventional fluorescence microscopy, where it is common practice to select high intensity regions for improved signal intensity and better signal to noise ratios. This study also documents application of CLSM to microstructural characterization of Tasmanites microfossils. Finally, based on an extant empirical relation between conventional λmax values and bitumen reflectance, λmax values from CLSM of Tasmanites microfossils can be used to calculate a bitumen reflectance equivalent value. The results presented herein can be used as a basis to broaden the future application of CLSM in the geological sciences into hydrocarbon prospecting and basin analysis.

  7. Optimizing the fluorescent yield in two-photon laser scanning microscopy with dispersion compensation

    Science.gov (United States)

    Field, Jeffrey J.; Carriles, Ramón; Sheetz, Kraig E.; Chandler, Eric V.; Hoover, Erich E.; Tillo, Shane E.; Hughes, Thom E.; Sylvester, Anne W.; Kleinfeld, David; Squier, Jeff A.

    2014-01-01

    A challenge for nonlinear imaging in living tissue is to maximize the total fluorescent yield from each fluorophore. We investigated the emission rates of three fluorophores – rhodamine B, a red fluorescent protein, and CdSe quantum dots – while manipulating the phase of the laser excitation pulse at the focus. In all cases a transform-limited pulse maximized the total yield to insure the highest signal-to-noise ratio. Further, we find evidence of fluorescence anti-bleaching in quantum dot samples. PMID:20588500

  8. Measuring tubulin content in Toxoplasma gondii: A comparison of laser-scanning confocal and wide-field fluorescence microscopy

    Science.gov (United States)

    Swedlow, Jason R.; Hu, Ke; Andrews, Paul D.; Roos, David S.; Murray, John M.

    2002-01-01

    Toxoplasma gondii is an intracellular parasite that proliferates within most nucleated cells, an important human pathogen, and a model for the study of human and veterinary parasitic infections. We used a stable yellow fluorescent protein-α-tubulin transgenic line to determine the structure of the microtubule cytoskeleton in T. gondii. Imaging of living yellow fluorescent protein-α-tubulin parasites by laser-scanning confocal microscopy (LSCM) failed to resolve the 22 subpellicular microtubules characteristic of the parasite cytoskeleton. To understand this result, we analyzed sources of noise in the LSCM and identified illumination fluctuations on time scales from microseconds to hours that introduce significant amounts of noise. We confirmed that weakly fluorescent structures could not be imaged in LSCM by using fluorescent bead standards. By contrast, wide-field microscopy (WFM) did visualize weak fluorescent standards and the individual microtubules of the parasite cytoskeleton. We therefore measured the fluorescence per unit length of microtubule by using WFM and used this information to estimate the tubulin content of the conoid (a structure important for T. gondii infection) and in the mitotic spindle pole. The conoid contains sufficient tubulin for ≈10 microtubule segments of 0.5-μm length, indicating that tubulin forms the structural core of the organelle. We also show that the T. gondii mitotic spindle contains ≈1 microtubule per chromosome. This analysis expands the understanding of structures used for invasion and intracellular proliferation by an important human pathogen and shows the advantage of WFM combined with image deconvolution over LSCM for quantitative studies of weakly fluorescent structures in moderately thin living cells. PMID:11830634

  9. Intravitreal concentrations of a near-infrared fluorescence-labeled biotherapeutic determined in situ using confocal scanning laser ophthalmoscopy.

    Science.gov (United States)

    Basile, Anthony S; Glazier, Genevieve; Lee, Alice; Jiang, Li-Ying; Johnson, Theodore R; Shields, Michael J; Vezina, Mark; Doppalapudi, Venkata R

    2011-09-01

    The pharmacokinetics of ophthalmic biotherapeutics are difficult to determine in human vitreous humor. Because of the high transparency of living tissue to near-infrared (NIR) light, the temporal changes in vitreous concentrations of a biomolecule labeled with an NIR fluorescent probe can be monitored in situ with a scanning laser ophthalmoscope (SLO). A humanized IgG was labeled with the NIR probe IRDye800CW (CVX-4164). Rabbits were given CVX-4164 intravitreally, and NIR fluorescence intensity was measured in the central plane of the vitreous humor with an SLO. Fluorescence intensities were converted to concentrations by using standard curves. Little background fluorescence was detected, and the minimum detectable concentration of CVX-4164 was CVX-4164 determined in situ declined with time, with C(max) ≈ 1 μM and t½ = 145 hours (112-μg dose). The t½ of CVX-4164 was approximately three times greater than that of the IRDye800CW alone, whereas the vitreal clearance (CL) and volume of distribution (V(ss)) of the native dye were approximately 2000- and 550-fold greater than that of the conjugate. CVX-4164 concentrations determined in situ were 2.6 to 4.4 times higher than those determined by ex vivo NIR fluorescence or ELISA in homogenized vitreous humor, reflecting the greater spatial resolution of in situ imaging. Moreover, vitreal concentrations determined in situ were >3 orders of magnitude greater than plasma concentrations of CVX-4164, as determined by ELISA, and had a different kinetic profile. This study demonstrates the feasibility of determining the pharmacokinetics of intraocular biotherapeutics labeled with NIR fluorescent probes by in situ monitoring.

  10. Precision automation of cell type classification and sub-cellular fluorescence quantification from laser scanning confocal images

    Directory of Open Access Journals (Sweden)

    Hardy Craig Hall

    2016-02-01

    Full Text Available While novel whole-plant phenotyping technologies have been successfully implemented into functional genomics and breeding programs, the potential of automated phenotyping with cellular resolution is largely unexploited. Laser scanning confocal microscopy has the potential to close this gap by providing spatially highly resolved images containing anatomic as well as chemical information on a subcellular basis. However, in the absence of automated methods, the assessment of the spatial patterns and abundance of fluorescent markers with subcellular resolution is still largely qualitative and time-consuming. Recent advances in image acquisition and analysis, coupled with improvements in microprocessor performance, have brought such automated methods within reach, so that information from thousands of cells per image for hundreds of images may be derived in an experimentally convenient time-frame. Here, we present a MATLAB-based analytical pipeline to 1 segment radial plant organs into individual cells, 2 classify cells into cell type categories based upon random forest classification, 3 divide each cell into sub-regions, and 4 quantify fluorescence intensity to a subcellular degree of precision for a separate fluorescence channel. In this research advance, we demonstrate the precision of this analytical process for the relatively complex tissues of Arabidopsis hypocotyls at various stages of development. High speed and robustness make our approach suitable for phenotyping of large collections of stem-like material and other tissue types.

  11. A Generalization of Theory for Two-Dimensional Fluorescence Recovery after Photobleaching Applicable to Confocal Laser Scanning Microscopes

    Science.gov (United States)

    Kang, Minchul; Day, Charles A.; Drake, Kimberly; Kenworthy, Anne K.; DiBenedetto, Emmanuele

    2009-01-01

    Abstract Fluorescence recovery after photobleaching (FRAP) using confocal laser scanning microscopes (confocal FRAP) has become a valuable technique for studying the diffusion of biomolecules in cells. However, two-dimensional confocal FRAP sometimes yields results that vary with experimental setups, such as different bleaching protocols and bleaching spot sizes. In addition, when confocal FRAP is used to measure diffusion coefficients (D) for fast diffusing molecules, it often yields D-values that are one or two orders-of-magnitude smaller than that predicted theoretically or measured by alternative methods such as fluorescence correlation spectroscopy. Recently, it was demonstrated that this underestimation of D can be corrected by taking diffusion during photobleaching into consideration. However, there is currently no consensus on confocal FRAP theory, and no efforts have been made to unify theories on conventional and confocal FRAP. To this end, we generalized conventional FRAP theory to incorporate diffusion during photobleaching so that analysis by conventional FRAP theory for a circular region of interest is easily applicable to confocal FRAP. Finally, we demonstrate the accuracy of these new (to our knowledge) formulae by measuring D for soluble enhanced green fluorescent protein in aqueous glycerol solution and in the cytoplasm and nucleus of COS7 cells. PMID:19720039

  12. A sensitive and versatile laser scanning confocal optical microscope for single-molecule fluorescence at 77 K.

    Science.gov (United States)

    Hirschfeld, V; Hübner, C G

    2010-11-01

    We developed a cryostat suitable for a laser scanning confocal microscope which allows for a short working distance and thus the usage of an objective with a high numerical aperture ensuring high collection efficiency. The in situ preparation of a thin layer of amorphous water is realized in a part of the cryostat, a Dewar vessel, which is put onto a custom-made, liquid-nitrogen immersed spin-coater. First tests on the setup are performed on a perylenemonoimide/polymethyl methacrylate model system using a standard oil objective and a dry objective at ambient temperature as well as a dry objective at liquid nitrogen temperature (77 K). Fluorescence resonance energy transfer (FRET) measurements on doubly labeled, freeze-quenched polyproline chains show the applicability of the new method on biomolecules. The alternating laser excitation (ALEX) is modified to a line-scanning process (slow ALEX) to optimize the sorting of the labeled molecules. Photophysics and photochemistry at liquid nitrogen temperature are investigated.

  13. Design of an affordable fluorescence confocal laser scanning microscope for medical diagnostics

    Science.gov (United States)

    Bechtel, Christin; Knobbe, Jens; Grüger, Heinrich; Lakner, Hubert

    2012-12-01

    Confocal fluorescence microscopes are a promising imaging tool in medical diagnostics due to their capability to selectively survey cross-sections of individual layers from `thick' samples. Non-invasive depth resolved investigation of neoplastic skin disorders is one example among other applications. However these microscopes are at present uncommon in medical practice. This is due to their main application area in research. The instruments dealt with here are generally complex, stationary units and are accordingly cost-intensive. It is for this reason, that we have designed a robust and portable MEMS based confocal fluorescence microscope with a field of view of 0.6mm x 0.6mm. This has been made possible by the integration of a 2D micro scanner mirror developed at Fraunhofer IPMS. A variable acquisition depth of cross-sectional images of the fluorescence specimen is enabled by an integrated z-shifter. With the use of commercially available optics an optical demonstrator set up has been realized. To characterize and to demonstrate the ability of this system test measurements were performed. The resolution of the microscope is better than 228 lp/mm determined by 1951 USAF resolution test target. Images of various biological samples are presented and optical sectioning capabilities are shown. A comparison of the measured with the predicted system performance will be given.

  14. Scanning laser Doppler vibrometry

    DEFF Research Database (Denmark)

    Brøns, Marie; Thomsen, Jon Juel

    With a Scanning Laser Doppler Vibrometer (SLDV) a vibrating surface is automatically scanned over predefined grid points, and data processed for displaying vibration properties like mode shapes, natural frequencies, damping ratios, and operational deflection shapes. Our SLDV – a PSV-500H from...

  15. Volumetric fluorescence retinal imaging in vivo over a 30-degree field of view by oblique scanning laser ophthalmoscopy (oSLO).

    Science.gov (United States)

    Zhang, Lei; Song, Weiye; Shao, Di; Zhang, Sui; Desai, Manishi; Ness, Steven; Roy, Sayon; Yi, Ji

    2018-01-01

    While fluorescent contrast is widely used in ophthalmology, three-dimensional (3D) fluorescence retinal imaging over a large field of view (FOV) has been challenging. In this paper, we describe a novel oblique scanning laser ophthalmoscopy (oSLO) technique that provides 3D volumetric fluorescence retinal imaging with only one raster scan. The technique utilizes scanned oblique illumination and angled detection to obtain fluorescent cross-sectional images, analogous to optical coherence tomography (OCT) line scans (or B-scans). By breaking the coaxial optical alignment used in conventional retinal imaging modalities, depth resolution is drastically improved. To demonstrate the capability of oSLO, we have performed in vivo volumetric fluorescein angiography (FA) of the rat retina with ~25μm depth resolution and over a 30° FOV. Using depth segmentation, oSLO can obtain high contrast images of the microvasculature down to single capillaries in 3D. The multi-modal nature of oSLO also allows for seamless combination with simultaneous OCT angiography.

  16. QUANTITATIVE CONFOCAL LASER SCANNING MICROSCOPY

    Directory of Open Access Journals (Sweden)

    Merete Krog Raarup

    2011-05-01

    Full Text Available This paper discusses recent advances in confocal laser scanning microscopy (CLSM for imaging of 3D structure as well as quantitative characterization of biomolecular interactions and diffusion behaviour by means of one- and two-photon excitation. The use of CLSM for improved stereological length estimation in thick (up to 0.5 mm tissue is proposed. The techniques of FRET (Fluorescence Resonance Energy Transfer, FLIM (Fluorescence Lifetime Imaging Microscopy, FCS (Fluorescence Correlation Spectroscopy and FRAP (Fluorescence Recovery After Photobleaching are introduced and their applicability for quantitative imaging of biomolecular (co-localization and trafficking in live cells described. The advantage of two-photon versus one-photon excitation in relation to these techniques is discussed.

  17. Scanning Color Laser Microscope

    Science.gov (United States)

    Awamura, D.; Ode, T.; Yonezawa, M.

    1988-01-01

    A confocal color laser microscope which utilizes a three color laser light source (Red: He-Ne, Green: Ar, Blue: Ar) has been developed and is finding useful applications in the semiconductor field. The color laser microscope, when compared to a conventional microscope, offers superior color separation, higher resolution, and sharper contrast. Recently some new functions including a Focus Scan Memory, a Surface Profile Measurement System, a Critical Dimension Measurement system (CD) and an Optical Beam Induced Current Function (OBIC) have been developed for the color laser microscope. This paper will discuss these new features.

  18. The laser scanning camera

    International Nuclear Information System (INIS)

    Jagger, M.

    The prototype development of a novel lenseless camera is reported which utilises a laser beam scanned in a raster by means of orthogonal vibrating mirrors to illuminate the field of view. Laser light reflected from the scene is picked up by a conveniently sited photosensitive device and used to modulate the brightness of a T.V. display scanned in synchronism with the moving laser beam, hence producing a T.V. image of the scene. The camera which needs no external lighting system can act in either a wide angle mode or by varying the size and position of the raster can be made to zoom in to view in detail any object within a 40 0 overall viewing angle. The resolution and performance of the camera are described and a comparison of these aspects is made with conventional T.V. cameras. (author)

  19. Measurements of Bacterial Concentrations on a Millimeter Scale in Ice Cores With a Scanning Laser Fluorescence Spectrometer

    Science.gov (United States)

    Price, P.; Rohde, R. A.; Bramall, N. E.; Bay, R. C.

    2006-12-01

    -rich wetland material from the base of GISP2 being repeatedly entrained into the ice. In the basal ice, which contains very high concentrations of both silt and microbes (Tung et al., 2006), the tryptophan signal seems to have been obscured by mineral grains. In many sections of ice cores we found very high spikes of tryptophan-like fluorescence in sub-mm depth regions. Our interpretation, which we will follow up in future work, is that the TUCS laser-excitation beam occasionally intersected veins at triple junctions in the ice, where organic material had been concentrated via rejection from the growing ice grains. Micron-size microbes in veins are known to metabolize at a very low rate via redox reactions on impurities (Price, 2000). An additional virtue of the TUCS technique is its ability to serve as a very sensitive probe of drill fluid contamination. We identified residual drill fluid on interior surfaces of a number of Vostok core sections, with the amount of contamination varying by orders of magnitude from sample to sample. In support of the WAIS Divide drilling project we also measured the rate of evaporation of drill fluid at -24 C after it was deliberately coated onto ice samples for our inspection at NICL. Though a valuable probe of drill fluid contamination, even low levels of drill fluid can prevent the TUCS from registering an accurate reading of native fluorescence. The success of this initial survey of ice cores indicates that UV fluorimetry can be a powerful new non-destructive tool with numerous applications to microbiology and climatology. This research was supported in part by NSF grant ANT-0440609.

  20. Noise analysis of a white-light supercontinuum light source for multiple wavelength confocal laser scanning fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    McConnell, Gail [Centre for Biophotonics, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow, G4 0NR (United Kingdom)

    2005-08-07

    Intensity correlations of a Ti : sapphire, Kr/Ar and a white-light supercontinuum were performed to quantify the typical signal amplitude fluctuations and hence ascertain the comparative output stability of the white-light supercontinuum source for confocal laser scanning microscopy (CLSM). Intensity correlations across a two-pixel sample (n = 1000) of up to 98%, 95% and 94% were measured for the Ti : sapphire, Kr/Ar and white-light supercontinuum source, respectively. The white-light supercontinuum noise level is therefore acceptable for CLSM, with the added advantage of wider wavelength flexibility over traditional CLSM excitation sources. The relatively low-noise white-light supercontinuum was then used to perform multiple wavelength sequential CLSM of guinea pig detrusor to confirm the reliability of the system and to demonstrate system flexibility.

  1. Self-interference fluorescence microscopy: three dimensional fluorescence imaging without depth scanning

    NARCIS (Netherlands)

    de Groot, M.; Evans, C.L.; de Boer, J.F.

    2012-01-01

    We present a new method for high-resolution, three-dimensional fluorescence imaging. In contrast to beam-scanning confocal microscopy, where the laser focus must be scanned both laterally and axially to collect a volume, we obtain depth information without the necessity of depth scanning. In this

  2.   In situ identification of streptococci and other bacteria in initial dental biofilm by confocal laser scanning microscopy and fluorescence in situ hybridization

    DEFF Research Database (Denmark)

    Dige, Irene; Kilian, Mogens; Nilsson, Holger

    2007-01-01

    Confocal laser scanning microscopy (CLSM) has been employed as a method for studying intact natural biofilm. When combined with fluorescence in situ hybridization (FISH) it is possible to analyze spatial relationships and changes of specific members of microbial populations over time. The aim...... of this study was to perform a systematic description of the pattern of initial dental biofilm formation by applying 16S rRNA- targeted oligonucleotide probes to the identification of streptococci and other bacteria, and to evaluate the usefulness of the combination of CLSM and FISH for structural studies...... of bacterial populations in dental biofilm. Biofilms were collected on stan- dardized glass slabs mounted in intra-oral appliances and worn by 10 individuals for 6, 12, 24 or 48 h. After intra-oral exposure the biofilms were labelled with probes against either streptococci (STR405) or all bacteria (EUB338...

  3. Laser-induced fluorescence imaging of bacteria

    Science.gov (United States)

    Hilton, Peter J.

    1998-12-01

    This paper outlines a method for optically detecting bacteria on various backgrounds, such as meat, by imaging their laser induced auto-fluorescence response. This method can potentially operate in real-time, which is many times faster than current bacterial detection methods, which require culturing of bacterial samples. This paper describes the imaging technique employed whereby a laser spot is scanned across an object while capturing, filtering, and digitizing the returned light. Preliminary results of the bacterial auto-fluorescence are reported and plans for future research are discussed. The results to date are encouraging with six of the eight bacterial strains investigated exhibiting auto-fluorescence when excited at 488 nm. Discrimination of these bacterial strains against red meat is shown and techniques for reducing background fluorescence discussed.

  4. Fluorescent scanning laser ophthalmoscopy for cellular resolution in vivo mouse retinal imaging: benefits and drawbacks of implementing adaptive optics (Conference Presentation)

    Science.gov (United States)

    Zhang, Pengfei; Goswami, Mayank; Pugh, Edward N.; Zawadzki, Robert J.

    2016-03-01

    Scanning Laser Ophthalmoscopy (SLO) is a very important imaging tool in ophthalmology research. By combing with Adaptive Optics (AO) technique, AO-SLO can correct for ocular aberrations resulting in cellular level resolution, allowing longitudinal studies of single cells morphology in the living eyes. The numerical aperture (NA) sets the optical resolution that can be achieve in the "classical" imaging systems. Mouse eye has more than twice NA of the human eye, thus offering theoretically higher resolution. However, in most SLO based imaging systems the imaging beam size at mouse pupil sets the NA of that instrument, while most of the AO-SLO systems use almost the full NA of the mouse eye. In this report, we first simulated the theoretical resolution that can be achieved in vivo for different imaging beam sizes (different NA), assumingtwo cases: no aberrations and aberrations based on published mouse ocular wavefront data. Then we imaged mouse retinas with our custom build SLO system using different beam sizes to compare these results with theory. Further experiments include comparison of the SLO and AO-SLO systems for imaging different type of fluorescently labeled cells (microglia, ganglion, photoreceptors, etc.). By comparing those results and taking into account systems complexity and ease of use, the benefits and drawbacks of two imaging systems will be discussed.

  5. Laser scanning laser diode photoacoustic microscopy system.

    Science.gov (United States)

    Erfanzadeh, Mohsen; Kumavor, Patrick D; Zhu, Quing

    2018-03-01

    The development of low-cost and fast photoacoustic microscopy systems enhances the clinical applicability of photoacoustic imaging systems. To this end, we present a laser scanning laser diode-based photoacoustic microscopy system. In this system, a 905 nm, 325 W maximum output peak power pulsed laser diode with 50 ns pulsewidth is utilized as the light source. A combination of aspheric and cylindrical lenses is used for collimation of the laser diode beam. Two galvanometer scanning mirrors steer the beam across a focusing aspheric lens. The lateral resolution of the system was measured to be ∼21 μm using edge spread function estimation. No averaging was performed during data acquisition. The imaging speed is ∼370 A-lines per second. Photoacoustic microscopy images of human hairs, ex vivo mouse ear, and ex vivo porcine ovary are presented to demonstrate the feasibility and potentials of the proposed system.

  6. Application of Confocal Laser Scanning Microscopy in Biology and Medicine

    Directory of Open Access Journals (Sweden)

    I. A. Volkov

    2014-01-01

    Full Text Available Fluorescence confocal laser scanning microscopy and reflectance confocal laser scanning microscopy are up-to-date highend study methods. Confocal microscopy is used in cell biology and medicine. By using confocal microscopy, it is possible to study bioplasts and localization of protein molecules and other compounds relative to cell or tissue structures, and to monitor dynamic cell processes. Confocal microscopes enable layer-by-layer scanning of test items to create demonstrable 3D models. As compared to usual fluorescent microscopes, confocal microscopes are characterized by a higher contrast ratio and image definition.

  7. DIAGNOdent laser fluorescence assessment of endodontic infection.

    Science.gov (United States)

    Sainsbury, Andrew L; Bird, Philip S; Walsh, Laurence J

    2009-10-01

    Real-time assessment of the microbial status of the root canal system would be useful in clinical endodontic practice for determining endpoints of biomechanical treatment. This laboratory study used an existing laser fluorescence device, the DIAGNOdent (KaVo, Biberach, Germany), in a proof-of-concept study. Visible laser red light (wavelength 655 nm) was used to elicit fluorescence emissions in the near-infrared range from infected and uninfected root canals. A prototype sapphire tip designed for periodontal assessment was used to analyze the pulp chamber and coronal third of the root canal system in extracted teeth. The fluorescence properties of bacterial cultures, monospecies biofilms in root canals, pulpal soft tissues, and sound dentin were also evaluated, together with 50 extracted teeth with known endodontic pathology. Sound dentin and healthy pulpal soft tissue gave an average fluorescence reading of 5 (on a scale of 100), whereas biofilms of Enterococcus faecalis and Streptococcus mutans established in root canals showed a progressive increase in fluorescence over time. Fluorescence readings reduced to the "healthy" threshold reading of 5 when root canals were endodontically treated, and the experimentally created bacterial biofilms were removed completely. High fluorescence readings were recorded in the root canals and pulp chambers of extracted teeth with radiographic evidence of periapical pathology and scanning electron microscopy evidence of bacterial infection. The use of the DIAGNOdent fluorescence approach for the assessment of the status of the pulp chamber and root canal system holds promise for clinical application; once more, flexible tips can be developed for gaining greater penetration into middle and apical thirds of the root canal.

  8. Coherent laser scanning diffraction microscopy

    International Nuclear Information System (INIS)

    Dierolf, Martin; Thibault, Pierre; Kewish, Cameron M; Menzel, Andreas; Bunk, Oliver; Pfeiffer, Franz

    2009-01-01

    Coherent diffractive imaging (CDI) is a promising approach to high-resolution x-ray microscopy. While CDI typically has a rather limited field of view, this problem can be solved by ptychography, a technique for which an extended object is raster scanned by a compact coherent illumination probe. Significant overlap of illumination for adjacent scan points allows then a self-consistent reconstruction from the entirety of collected coherent diffraction patterns. However, current reconstruction schemes require accurate a priori knowledge of the probe. Our recently developed new algorithm for ptychographic data sets allows us to simultaneously reconstruct both object and illuminating probe. We demonstrate the application of the new method in a test experiment with visible laser light showing that intricate illumination functions can be retrieved reliably.

  9. Clinical applications of laser scanning cytometry.

    Science.gov (United States)

    Tárnok, Attila; Gerstner, Andreas O H

    2002-06-15

    This study reviews existing and potential clinical applications of laser scanning cytometry (LSC) and outlines possible future developments. LSC provides a technology for solid phase cytometry. Fluorochrome-labeled specimens are immobilized on microscopic slides that are placed on a conventional epifluorescence microscope and analyzed by one or two lasers. Data comparable to flow cytometry are generated. In addition, the position of each event is recorded, a feature that allows relocalization and visualization of each measured event. The major advantage of LSC compared with other cytometric methods is the combination of two features: (a) the minimal clinical sample volume needed and (b) the connection of fluorescence data and morphological information for the measured event. Since the introduction of LSC, numerous methods have been established for the analysis of cells, cellular compartments, and tissues. Although most cytometric methods use only two or three colors, the characterization of specimens with up to five fluorochromes is possible. Most clinical applications have been designed to determine ploidy and immunophenotype; other applications include analyses of tissue biopsies and sections, fluorescence in situ hybridization, and the combination of vital and nonvital information on a single-cell basis. With the currently available assays, LSC has proven its wide spectrum of clinical applicability in slide-based cytometry and can be introduced as a standard technology in multiple clinical settings. Copyright 2002 Wiley-Liss, Inc.

  10. Fluorescence correlation spectroscopy, Raster image correlation spectroscopy and Number & Brightness on a commercial confocal laser scanning microscope with analog detectors (Nikon C1)

    Science.gov (United States)

    Moens, Pierre D.J.; Gratton, Enrico; Salvemini, Iyrri L.

    2010-01-01

    Fluorescence correlation spectroscopy (FCS) was developed in 1972 by Magde, Elson and Webb (Magde et al., 1972). Photon counting detectors and avalanche photodiodes have become standards in FCS to the point that there is a widespread belief that these detectors are essential to perform FCS experiments, despite the fact that FCS was developed using analog detectors. Spatial and temporal intensity fluctuation correlations using analog detection on a commercial Olympus Fluoview 300 microscope has been reported by Brown et al. (2008). However, each analog instrument has its own idiosyncrasies that need to be understood before using the instrument for FCS. In this work we explore the capabilities of the Nikon C1, a low cost confocal microscope, to obtain single point FCS, Raster-scan Image Correlation Spectroscopy (RICS) and Number & Brightness data both in solution and incorporated into the membrane of Giant Unilamellar Vesicles (GUVs). We show that it is possible to obtain dynamic information about fluorescent molecules from single point FCS, RICS and Number & Brightness using the Nikon C1. We highlighted the fact that care should be taken in selecting the acquisition parameters in order to avoid possible artifacts due to the detector noise. However, due to relatively large errors in determining the distribution of digital levels for a given microscope setting, the system is probably only adequate for determining relative brightness within the same image. PMID:20734406

  11. Fluorescence correlation spectroscopy, raster image correlation spectroscopy, and number and brightness on a commercial confocal laser scanning microscope with analog detectors (Nikon C1).

    Science.gov (United States)

    Moens, Pierre D J; Gratton, Enrico; Salvemini, Iyrri L

    2011-04-01

    Fluorescence correlation spectroscopy (FCS) was developed in 1972 by Magde, Elson and Webb. Photon counting detectors and avalanche photodiodes have become standards in FCS to the point that there is a widespread belief that these detectors are essential to perform FCS experiments, despite the fact that FCS was developed using analog detectors. Spatial and temporal intensity fluctuation correlations using analog detection on a commercial Olympus Fluoview 300 microscope have been reported by Brown et al. (2008). However, each analog instrument has its own idiosyncrasies that need to be understood before using the instrument for FCS. In this work, we explore the capabilities of the Nikon C1, a low-cost confocal microscope, to obtain single point FCS, Raster-scan image correlation spectroscopy (RICS), and Number and Brightness data both in solution and incorporated into the membrane of giant unilamellar vesicles. We show that it is possible to obtain dynamic information about fluorescent molecules from single point FCS, RICS, and Number and Brightness using the Nikon C1. We highlighted the fact that care should be taken in selecting the acquisition parameters to avoid possible artifacts due to the detector noise. However, due to relatively large errors in determining the distribution of digital levels for a given microscope setting, the system is probably only adequate for determining relative brightness within the same image. Copyright © 2010 Wiley-Liss, Inc.

  12. ScanImage: Flexible software for operating laser scanning microscopes

    Science.gov (United States)

    Pologruto, Thomas A; Sabatini, Bernardo L; Svoboda, Karel

    2003-01-01

    Background Laser scanning microscopy is a powerful tool for analyzing the structure and function of biological specimens. Although numerous commercial laser scanning microscopes exist, some of the more interesting and challenging applications demand custom design. A major impediment to custom design is the difficulty of building custom data acquisition hardware and writing the complex software required to run the laser scanning microscope. Results We describe a simple, software-based approach to operating a laser scanning microscope without the need for custom data acquisition hardware. Data acquisition and control of laser scanning are achieved through standard data acquisition boards. The entire burden of signal integration and image processing is placed on the CPU of the computer. We quantitate the effectiveness of our data acquisition and signal conditioning algorithm under a variety of conditions. We implement our approach in an open source software package (ScanImage) and describe its functionality. Conclusions We present ScanImage, software to run a flexible laser scanning microscope that allows easy custom design. PMID:12801419

  13. Scanning laser polarimetry in glaucoma.

    Science.gov (United States)

    Dada, Tanuj; Sharma, Reetika; Angmo, Dewang; Sinha, Gautam; Bhartiya, Shibal; Mishra, Sanjay K; Panda, Anita; Sihota, Ramanjit

    2014-11-01

    Glaucoma is an acquired progressive optic neuropathy which is characterized by changes in the optic nerve head and retinal nerve fiber layer (RNFL). White-on-white perimetry is the gold standard for the diagnosis of glaucoma. However, it can detect defects in the visual field only after the loss of as many as 40% of the ganglion cells. Hence, the measurement of RNFL thickness has come up. Optical coherence tomography and scanning laser polarimetry (SLP) are the techniques that utilize the evaluation of RNFL for the evaluation of glaucoma. SLP provides RNFL thickness measurements based upon the birefringence of the retinal ganglion cell axons. We have reviewed the published literature on the use of SLP in glaucoma. This review elucidates the technological principles, recent developments and the role of SLP in the diagnosis and monitoring of glaucomatous optic neuropathy, in the light of scientific evidence so far.

  14. Fluorescence imaging of reactive oxygen species by confocal laser scanning microscopy for track analysis of synchrotron X-ray photoelectric nanoradiator dose: X-ray pump-optical probe.

    Science.gov (United States)

    Jeon, Jae Kun; Han, Sung Mi; Kim, Jong Ki

    2016-09-01

    Bursts of emissions of low-energy electrons, including interatomic Coulomb decay electrons and Auger electrons (0-1000 eV), as well as X-ray fluorescence produced by irradiation of large-Z element nanoparticles by either X-ray photons or high-energy ion beams, is referred to as the nanoradiator effect. In therapeutic applications, this effect can damage pathological tissues that selectively take up the nanoparticles. Herein, a new nanoradiator dosimetry method is presented that uses probes for reactive oxygen species (ROS) incorporated into three-dimensional gels, on which macrophages containing iron oxide nanoparticles (IONs) are attached. This method, together with site-specific irradiation of the intracellular nanoparticles from a microbeam of polychromatic synchrotron X-rays (5-14 keV), measures the range and distribution of OH radicals produced by X-ray emission or superoxide anions ({\\rm{O}}_2^-) produced by low-energy electrons. The measurements are based on confocal laser scanning of the fluorescence of the hydroxyl radical probe 2-[6-(4'-amino)phenoxy-3H-xanthen-3-on-9-yl] benzoic acid (APF) or the superoxide probe hydroethidine-dihydroethidium (DHE) that was oxidized by each ROS, enabling tracking of the radiation dose emitted by the nanoradiator. In the range 70 µm below the irradiated cell, ^\\bullet{\\rm{OH}} radicals derived mostly from either incident X-ray or X-ray fluorescence of ION nanoradiators are distributed along the line of depth direction in ROS gel. In contrast, {\\rm{O}}_2^- derived from secondary electron or low-energy electron emission by ION nanoradiators are scattered over the ROS gel. ROS fluorescence due to the ION nanoradiators was observed continuously to a depth of 1.5 mm for both oxidized APF and oxidized DHE with relatively large intensity compared with the fluorescence caused by the ROS produced solely by incident primary X-rays, which was limited to a depth of 600 µm, suggesting dose enhancement as well as more

  15. Galvanometer scanning technology for laser additive manufacturing

    Science.gov (United States)

    Luo, Xi; Li, Jin; Lucas, Mark

    2017-02-01

    A galvanometer laser beam scanning system is an essential element in many laser additive manufacturing (LAM) technologies including Stereolithography (SLA), Selective Laser Sintering (SLS) and Selective Laser Melting (SLM). Understanding the laser beam scanning techniques and recent innovations in this field will greatly benefit the 3D laser printing system integration and technology advance. One of the challenges to achieve high quality 3D printed parts is due to the non-uniform laser power density delivered on the materials caused by the acceleration and deceleration movements of the galvanometer at ends of the hatching and outlining patterns. One way to solve this problem is to modulate the laser power as the function of the scanning speed during the acceleration or deceleration periods. Another strategy is to maintain the constant scanning speed while accurately coordinating the laser on and off operation throughout the job. In this paper, we demonstrate the high speed, high accuracy and low drift digital scanning technology that incorporates both techniques to achieve uniform laser density with minimal additional process development. With the constant scanning speed method, the scanner not only delivers high quality and uniform results, but also a throughput increase of 23% on a typical LAM job, compared to that of the conventional control method that requires galvanometer acceleration and deceleration movements.

  16. Laser line scan performance prediction

    Science.gov (United States)

    Mahoney, Kevin L.; Schofield, Oscar; Kerfoot, John; Giddings, Tom; Shirron, Joe; Twardowski, Mike

    2007-09-01

    The effectiveness of sensors that use optical measurements for the laser detection and identification of subsurface mines is directly related to water clarity. The primary objective of the work presented here was to use the optical data collected by UUV (Slocum Glider) surveys of an operational areas to estimate the performance of an electro-optical identification (EOID) Laser Line Scan (LLS) system during RIMPAC 06, an international naval exercise off the coast of Hawaii. Measurements of optical backscattering and beam attenuation were made with a Wet Labs, Inc. Scattering Absorption Meter (SAM), mounted on a Rutgers University/Webb Research Slocum glider. The optical data universally indicated extremely clear water in the operational area, except very close to shore. The beam-c values from the SAM sensor were integrated to three attenuation lengths to provide an estimate of how well the LLS would perform in detecting and identifying mines in the operational areas. Additionally, the processed in situ optical data served as near-real-time input to the Electro-Optic Detection Simulator, ver. 3 (EODES-3; Metron, Inc.) model for EOID performance prediction. Both methods of predicting LLS performance suggested a high probability of detection and probability of identification. These predictions were validated by the actual performance of the LLS as the EOID system yielded imagery from which reliable mine identification could be made. Future plans include repeating this work in more optically challenging water types to demonstrate the utility of pre-mission UUV surveys of operational areas as a tactical decision aid for planning EOID missions.

  17. Thermographic system with a laser scanning device

    International Nuclear Information System (INIS)

    Skvortsov, L A; Kirillov, V M

    2007-01-01

    It is shown that laser photothermal radiometry (LPTR) in combination with laser beam scanning within the instantaneous field of view of a single-element photodetector can be used to develop a scanning thermal emission microscope. An expression is derived for estimating its temperature resolution. The results of calculations are presented and the factors influencing the spatial lateral resolution of the technique and the time of image formation with the help of an acousto-optical deflector are analysed. (laser applications)

  18. Hybrid processing of laser scanning data

    Science.gov (United States)

    Badenko, Vladimir; Zotov, Dmitry; Fedotov, Alexander

    2018-03-01

    In this article the analysis of gaps in processing of raw laser scanning data and results of bridging the gaps discovered on the base of usage of laser scanning data for historic building information modeling is presented. The results of the development of a unified hybrid technology for the processing, storage, access and visualization of combined laser scanning and photography data about historical buildings are analyzed. The first result of the technology application for the historical building of St. Petersburg Polytechnic University shows reliability of the proposed approaches.

  19. Laser scanning of experimental solar cells

    Science.gov (United States)

    Plunkett, B. C.; Lasswell, P. G.

    1980-01-01

    A description is presented of a laser scanning instrument which makes it possible to display and measure the spatial response of a solar cell. Examples are presented to illustrate the use of generated micrographs in the isolation of flaws and features of the cell. The laser scanner system uses a 4 mW, CW helium-neon laser, operating a wavelength of 0.633 micrometers. The beam is deflected by two mirror galvanometers arranged to scan in orthogonal directions. After being focused on the solar cell by the beam focusing lens, the moving light spot raster scans the specimen. The current output of the photovoltaic device under test, as a function of the scan dot position, can be displayed in several modes. The laser scanner has proved to be a very useful diagnostic tool in optimizing the process design of transparent metal film photovoltaic devices on Zn3P2, a relatively new photovoltaic material.

  20. Multicolor Scanning Laser Imaging in Diabetic Retinopathy.

    Science.gov (United States)

    Ahmad, Mohammad S Z; Carrim, Zia Iqbal

    2017-11-01

    Diabetic retinopathy is a common cause of blindness in individuals younger than 60 years. Screening for retinopathy is undertaken using conventional color fundus photography and relies on the identification of hemorrhages, vascular abnormalities, exudates, and cotton-wool spots. These can sometimes be difficult to identify. Multicolor scanning laser imaging, a new imaging modality, may have a role in improving screening outcomes, as well as facilitating treatment decisions. Observational case series comprising two patients with known diabetes who were referred for further examination after color fundus photography revealed abnormal findings. Multicolor scanning laser imaging was undertaken. Features of retinal disease from each modality were compared. Multicolor scanning laser imaging provides superior visualization of retinal anatomy and pathology, thereby facilitating risk stratification and treatment decisions. Multicolor scanning laser imaging is a novel imaging technique offering the potential for improving the reliability of screening for diabetic retinopathy. Validation studies are warranted.

  1. Laser scanning camera inspects hazardous area

    International Nuclear Information System (INIS)

    Fryatt, A.; Miprode, C.

    1985-01-01

    Main operational characteristics of a new laser scanning camera are presented. The camera is intended primarily for low level high resolution viewing inside nuclear reactors. It uses a He-Ne laser beam raster; by detecting the reflected light by means of a phomultiplier, the subject under observation can be reconstructed in an electronic video store and reviewed on a conventional monitor screen

  2. Laser scan with upstream crystal #1

    CERN Document Server

    Gyr, Marcel

    1996-01-01

    A laser scan was performed with the new U-shaped crystal G5, which has a known miscut of +1 mrad and is installed at the upstream position #1 in the TEC. The aim was to cross-check the angular sensitivity of the stepping motor of the goniometer, which theoretically should be 1.98 µrad/step.

  3. Polarized differential-phase laser scanning microscope

    International Nuclear Information System (INIS)

    Chou Chien; Lyu, C.-W.; Peng, L.-C.

    2001-01-01

    A polarized differential-phase laser scanning microscope, which combines a polarized optical heterodyne Mach-Zehnder interferometer and a differential amplifier to scan the topographic image of a surface, is proposed. In the experiment the differential amplifier, which acts as a PM-AM converter, in the experiment, converting phase modulation (PM) into amplitude modulation (AM). Then a novel, to our knowledge, phase demodulator was proposed and implemented for the differential-phase laser scanning microscope. An optical grating (1800 lp/mm) was imaged. The lateral and the depth resolutions of the imaging system were 0.5 μm and 1 nm, respectively. The detection accuracy, which was limited by the reflectivity variation of the test surface, is discussed

  4. Laser induced fluorescence spectroscopy for FTU

    International Nuclear Information System (INIS)

    Hughes, T.P.

    1995-07-01

    Laser induced fluorescence spectroscopy (LIFS) is based on the absorption of a short pulse of tuned laser light by a group of atoms and the observation of the resulting fluorescence radiation from the excited state. Because the excitation is resonant it is very efficient, and the fluorescence can be many times brighter than the normal spontaneous emission, so low number densities of the selected atoms can be detected and measured. Good spatial resolution can be achieved by using a narrow laser beam. If the laser is sufficiently monochromatic, and it can be tuned over the absorption line profile of the selected atoms, information can also be obtained about the velocities of the atoms from the Doppler effect which can broaden and shift the line. In this report two topics are examined in detail. The first is the effect of high laser irradiance, which can cause 'power broadening' of the apparent absorption line profile. The second is the effect of the high magnetic field in FTU. Detailed calculations are given for LIFS of neutral iron and molybdenum atoms, including the Zeeman effect, and the implementation of LIFS for these atoms on FTU is discussed

  5. 21 CFR 872.1745 - Laser fluorescence caries detection device.

    Science.gov (United States)

    2010-04-01

    ... is to aid in the detection of tooth decay by measuring increased laser induced fluorescence. (b... aids in the detection of tooth decay by measuring increased laser induced fluorescence; and (3) The... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Diagnostic Devices § 872.1745 Laser fluorescence caries...

  6. MULTIPLATFORM APPROACH TO MOBILE LASER SCANNING

    Directory of Open Access Journals (Sweden)

    A. Kukko

    2012-07-01

    Full Text Available Mobile laser scanning is an emerging technology for capturing three-dimensional information from the surrounding objects. With state of the art sensors the achieved point cloud could capture fine details of the surroundings with good accuracy and effectiveness. Many of the applications deal with the civil engineering purposes in urban areas for traffic and city planning and modelling. In this article we present multiplatform mobile laser scanning solutions for mapping applications that require mobility in various terrains and river environments but yet produce high density point clouds with good reliability and accuracy. The ROAMER mobile laser scanning system was deployed in multitude of tasks from urban areas to climate research. The paper also introduces a completely new backpack Akhka platform for mobile lidar mapping of areas where wheeled vehicles cannot operate. The sensor set is the same in all of the approaches, but the carrying vessel was selected according to the application. This was possible thanks to a relatively light and compact yet simple design of the system. ROAMER system is one of the few high-end MLS systems that are easily adaptable to various platforms. In addition to technical description of the system we discuss the practical performance of the solutions through various applications in the fields of urban mapping, fluvial geomorphology, snow cover characterization and climate change monitoring.

  7. Laser-stimulated fluorescence in paleontology.

    Directory of Open Access Journals (Sweden)

    Thomas G Kaye

    Full Text Available Fluorescence using ultraviolet (UV light has seen increased use as a tool in paleontology over the last decade. Laser-stimulated fluorescence (LSF is a next generation technique that is emerging as a way to fluoresce paleontological specimens that remain dark under typical UV. A laser's ability to concentrate very high flux rates both at the macroscopic and microscopic levels results in specimens fluorescing in ways a standard UV bulb cannot induce. Presented here are five paleontological case histories that illustrate the technique across a broad range of specimens and scales. Novel uses such as back-lighting opaque specimens to reveal detail and detection of specimens completely obscured by matrix are highlighted in these examples. The recent cost reductions in medium-power short wavelength lasers and use of standard photographic filters has now made this technique widely accessible to researchers. This technology has the potential to automate multiple aspects of paleontology, including preparation and sorting of microfossils. This represents a highly cost-effective way to address paleontology's preparatory bottleneck.

  8. Laser-induced fluorescence for medical diagnostics

    International Nuclear Information System (INIS)

    Andersson Engels, S.

    1989-12-01

    Laser-induced fluorescence as a tool for tissue diagnostics is discussed. Both spectrally and time-resolved fluorescence signals are studied to optimize the demarcation of diseased lesions from normal tissue. The presentation is focused on two fields of application: the identification of malignant tumours and atherosclerotic plaques. Tissue autofluorescence as well as fluorescence from administered drugs have been utilized in diseased tissue diagnosis. The fluorescence criterion for tissue diagnosis is, as far as possible, chosen to be independent of unknown fluorescence parameters, which are not correlated to the type of tissue investigated. Both a dependence on biological parameters, such as light absorption in blood, and instrumental characteristics, such as excitation pulse fluctuations and detection geometry, can be minimized. Several chemical compounds have been studied in animal experiments after intraveneous injection to verify their capacity as malignant tumour marking drugs under laser excitation and fluorescence detection. Another objective of these studies was to improve our understanding of the mechanism and chemistry behind the retention of the various drugs in tissue. The properties of a chemical which maximize its selective retention in tumours are discussed. In order to utilize this diagnostic modality, three different clinically adapted sets of instrumentation have been developed and are presented. Two of the systems are nitrogen-laser-based fluorosensors; one is a point-monitoring system with full spectral resolution and the other one is an imaging system with up to four simultaneously recorded images in different spectral bands. The third system is a low-cost point-monitoring mercury-lamp-based fluoroscence emission as well as reflection characteristics of tissue. (author)

  9. Laser induced fluorescence of trapped molecular ions

    International Nuclear Information System (INIS)

    Winn, J.S.

    1980-10-01

    Laser induced fluoresence (LIF) spectra (laser excitation spectra) are conceptually among the most simple spectra to obtain. One need only confine a gaseous sample in a suitable container, direct a laser along one axis of the container, and monitor the sample's fluorescence at a right angle to the laser beam. As the laser wavelength is changed, the changes in fluorescence intensity map the absorption spectrum of the sample. (More precisely, only absorption to states which have a significant radiative decay component are monitored.) For ion spectroscopy, one could benefit in many ways by such an experiment. Most optical ion spectra have been observed by emission techniques, and, aside from the problems of spectral analysis, discharge emission methods often produce the spectra of many species, some of which may be unknown or uncertain. Implicit in the description of LIF given above is certainty as to the chemical identity of the carrier of the spectrum. This article describes a method by which the simplifying aspects of LIF can be extended to molecular ions

  10. Laser induced fluorescence of trapped molecular ions

    Energy Technology Data Exchange (ETDEWEB)

    Grieman, F.J.

    1979-10-01

    An experimental apparatus for obtaining the optical spectra of molecular ions is described. The experimental technique includes the use of three dimensional ion trapping, laser induced fluorescence, and gated photon counting methods. The ions, which are produced by electron impact, are confined in a radio-frequency quadrupole ion trap of cylindrical design. Because the quadrupole ion trap allows mass selection of the molecular ion desired for study, the analysis of the spectra obtained is greatly simplified. The ion trap also confines the ions to a region easily probed by a laser beam. 18 references.

  11. Laser induced fluorescence of trapped molecular ions

    International Nuclear Information System (INIS)

    Grieman, F.J.

    1979-10-01

    An experimental apparatus for obtaining the optical spectra of molecular ions is described. The experimental technique includes the use of three dimensional ion trapping, laser induced fluorescence, and gated photon counting methods. The ions, which are produced by electron impact, are confined in a radio-frequency quadrupole ion trap of cylindrical design. Because the quadrupole ion trap allows mass selection of the molecular ion desired for study, the analysis of the spectra obtained is greatly simplified. The ion trap also confines the ions to a region easily probed by a laser beam. 18 references

  12. Design and analysis of imagery system of laser scanning

    Science.gov (United States)

    Li, Tianze; Wang, Zhenhuan; Zhang, Xia; Hou, Luan; Jiang, Chuan

    2009-08-01

    This paper expounds the operation principle of laser scanning imagery system,after analyzing the light source, transmitter,receivewere and the continuous analogue electric signal which are in the laser scanning imagery system,a laser scanning imagery system is designed, the composition and main parts of the system were expounded. The performance referance date were reviewed.The characteristics of this systerm is that it not only can scanned but also can collect reflecting coefficient information and can do laser ranging.This paper analyze and disguess the scanning imagery system and the key technology of laser weapon, finally the applicating prospects of the system are described.

  13. Laser induced fluorescence of dental caries

    Science.gov (United States)

    Albin, S.; Byvik, C. E.; Buoncristiani, A. M.

    1988-01-01

    Significant differences between the optical spectra taken from sound regions of teeth and carious regions have been observed. These differences appear both in absorption and in laser induced fluorescence spectra. Excitation by the 488 nm line of an argon ion laser beam showed a peak in the emission intensity around 553 nm for the sound dental material while the emission peak from the carious region was red-shifted by approximately 40 nm. The relative absorption of carious region was significantly higher at 488 nm; however its fluorescence intensity peak was lower by an order of magnitude compared to the sound tooth. Implications of these results for a safe, reliable and early detection of dental caries are discussed.

  14. Mobile Laser Scanning for Indoor Modelling

    Science.gov (United States)

    Thomson, C.; Apostolopoulos, G.; Backes, D.; Boehm, J.

    2013-10-01

    The process of capturing and modelling buildings has gained increased focus in recent years with the rise of Building Information Modelling (BIM). At the heart of BIM is a process change for the construction and facilities management industries whereby a BIM aids more collaborative working through better information exchange, and as a part of the process Geomatic/Land Surveyors are not immune from the changes. Terrestrial laser scanning has been proscribed as the preferred method for rapidly capturing buildings for BIM geometry. This is a process change from a traditional measured building survey just with a total station and is aided by the increasing acceptance of point cloud data being integrated with parametric building models in BIM tools such as Autodesk Revit or Bentley Architecture. Pilot projects carried out previously by the authors to investigate the geometry capture and modelling of BIM confirmed the view of others that the process of data capture with static laser scan setups is slow and very involved requiring at least two people for efficiency. Indoor Mobile Mapping Systems (IMMS) present a possible solution to these issues especially in time saved. Therefore this paper investigates their application as a capture device for BIM geometry creation over traditional static methods through a fit-for-purpose test.

  15. Mobile Laser Scanning for Indoor Modelling

    Directory of Open Access Journals (Sweden)

    C. Thomson

    2013-10-01

    Full Text Available The process of capturing and modelling buildings has gained increased focus in recent years with the rise of Building Information Modelling (BIM. At the heart of BIM is a process change for the construction and facilities management industries whereby a BIM aids more collaborative working through better information exchange, and as a part of the process Geomatic/Land Surveyors are not immune from the changes. Terrestrial laser scanning has been proscribed as the preferred method for rapidly capturing buildings for BIM geometry. This is a process change from a traditional measured building survey just with a total station and is aided by the increasing acceptance of point cloud data being integrated with parametric building models in BIM tools such as Autodesk Revit or Bentley Architecture. Pilot projects carried out previously by the authors to investigate the geometry capture and modelling of BIM confirmed the view of others that the process of data capture with static laser scan setups is slow and very involved requiring at least two people for efficiency. Indoor Mobile Mapping Systems (IMMS present a possible solution to these issues especially in time saved. Therefore this paper investigates their application as a capture device for BIM geometry creation over traditional static methods through a fit-for-purpose test.

  16. MEMS scanned laser head-up display

    Science.gov (United States)

    Freeman, Mark O.

    2011-03-01

    Head-up displays (HUD) in automobiles and other vehicles have been shown to significantly reduce accident rates by keeping the driver's eyes on the road. The requirements for automotive HUDs are quite demanding especially in terms of brightness, dimming range, supplied power, and size. Scanned laser display technology is particularly well-suited to this application since the lasers can be very efficiently relayed to the driver's eyes. Additionally, the lasers are only turned on where the light is needed in the image. This helps to provide the required brightness while minimizing power and avoiding a background glow that disturbs the see-through experience. Microvision has developed a couple of HUD architectures that are presented herein. One design uses an exit pupil expander and relay optics to produce a high quality virtual image for built-in systems where the image appears to float above the hood of the auto. A second design uses a patented see-through screen technology and pico projector to make automotive HUDs available to anyone with a projector. The presentation will go over the basic designs for the two types of HUD and discuss design tradeoffs.

  17. Laser induced fluorescence model of human goiter

    Science.gov (United States)

    Jaliashvili, Z. V.; Medoidze, T. D.; Mardaleishvili, K. M.; Ramsden, J. J.; Melikishvili, Z. G.

    2008-03-01

    Laser induced fluorescence (LIF) with wide area surveillance for resected thyroid tissue solid chunks is presented. The characteristic LIF spectra of goiter were established. The state of tissue at each point represents a superposition of normal and pathology states. To our knowledge two co-existing pathological effects were observed optically for the first time. It is demonstrated that the LIF spectral functions and their intensities well-labeled such areas and represent a good tool for medical diagnostics of goiter and for the definition of the degree of abnormality and geometrical sizes of these areas.

  18. Wide field fluorescence imaging in narrow passageways using scanning fiber endoscope technology

    Science.gov (United States)

    Lee, Cameron M.; Chandler, John E.; Seibel, Eric J.

    2010-02-01

    An ultrathin scanning fiber endoscope (SFE) has been developed for high resolution imaging of regions in the body that are commonly inaccessible. The SFE produces 500 line color images at 30 Hz frame rate while maintaining a 1.2-1.7 mm outer diameter. The distal tip of the SFE houses a 9 mm rigid scan engine attached to a highly flexible tether (minimum bend radius technologies, the unique characteristics of this system have allowed the SFE to navigate narrow passages without sacrificing image quality. To date, the SFE has been used for in vivo imaging of the bile duct, esophagus and peripheral airways. In this study, the standard SFE operation was tailored to capture wide field fluorescence images and spectra. Green (523 nm) and blue (440 nm) lasers were used as illumination sources, while the white balance gain values were adjusted to accentuate red fluorescence signal. To demonstrate wide field fluorescence imaging of small lumens, the SFE was inserted into a phantom model of a human pancreatobiliary tract and navigated to a custom fluorescent target. Both wide field fluorescence and standard color images of the target were captured to demonstrate multimodal imaging.

  19. RADIOMETRIC CALIBRATION OF AIRBORNE LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    Pilarska Magdalena

    2016-12-01

    Full Text Available Airborne laser scanning (ALS is widely used passive remote sensing technique. The radiometric calibration of ALS data is presented in this article. This process is a necessary element in data processing since it eliminates the influence of the external factors on the obtained values of radiometric features such as range and incidence angle. The datasets were captured with three different laser scanners; since each of these operates at a different wavelength (532, 106 4 and 1550 nm this makes the experiment more interesting. Radiometric calibration is a complex process, and a short theoretical background is therefore provided at the beginning of the article. The applied calibration procedure relies on areas with known reflectivity . The calibration region s should exhibit s table radiometric properties, therefore asphalt is used to calibrate each dataset and calculate a calibration constant for each flight block (wavelength independently . Following this, the results of radiometric calibration , reflectance and backscattering coefficient, are presented and discussed in detail. Finally, the obtained reflectance values are compared with spectral characteristics. It could be shown that the reflectance values which result from radiometric calibration are similar to values presented on spectral characteristics.

  20. Ultratrace analysis of transuranic actinides by laser-induced fluorescence

    Science.gov (United States)

    Miller, Steven M.

    1988-01-01

    Ultratrace quantities of transuranic actinides are detected indirectly by their effect on the fluorescent emissions of a preselected fluorescent species. Transuranic actinides in a sample are coprecipitated with a host lattice material containing at least one preselected fluorescent species. The actinide either quenches or enhances the laser-induced fluorescence of the preselected fluorescent species. The degree of enhancement or quenching is quantitatively related to the concentration of actinide in the sample.

  1. Two-photon flow cytometer with laser scanning Bessel beams

    Science.gov (United States)

    Wang, Yongdong; Ding, Yu; Ray, Supriyo; Paez, Aurelio; Xiao, Chuan; Li, Chunqiang

    2016-03-01

    Flow cytometry is an important technique in biomedical discovery for cell counting, cell sorting and biomarker detection. In vivo flow cytometers, based on one-photon or two-photon excited fluorescence, have been developed for more than a decade. One drawback of laser beam scanning two-photon flow cytometer is that the two-photon excitation volume is fairly small due to the short Rayleigh range of a focused Gaussian beam. Hence, the sampling volume is much smaller than one-photon flow cytometry, which makes it challenging to count or detect rare circulating cells in vivo. Bessel beams have narrow intensity profiles with an effective spot size (FWHM) as small as several wavelengths, making them comparable to Gaussian beams. More significantly, the theoretical depth of field (propagation distance without diffraction) can be infinite, making it an ideal solution as a light source for scanning beam flow cytometry. The trade-off of using Bessel beams rather than a Gaussian beam is the fact that Bessel beams have small concentric side rings that contribute to background noise. Two-photon excitation can reduce this noise, as the excitation efficiency is proportional to intensity squared. Therefore, we developed a two-photon flow cytometer using scanned Bessel beams to form a light sheet that intersects the micro fluidic channel.

  2. Laser scanning cytometry as a tool for biomarker validation

    Science.gov (United States)

    Mittag, Anja; Füldner, Christiane; Lehmann, Jörg; Tarnok, Attila

    2013-03-01

    Biomarkers are essential for diagnosis, prognosis, and therapy. As diverse is the range of diseases the broad is the range of biomarkers and the material used for analysis. Whereas body fluids can be relatively easily obtained and analyzed, the investigation of tissue is in most cases more complicated. The same applies for the screening and the evaluation of new biomarkers and the estimation of the binding of biomarkers found in animal models which need to be transferred into applications in humans. The latter in particular is difficult if it recognizes proteins or cells in tissue. A better way to find suitable cellular biomarkers for immunoscintigraphy or PET analyses may be therefore the in situ analysis of the cells in the respective tissue. In this study we present a method for biomarker validation using Laser Scanning Cytometry which allows the emulation of future in vivo analysis. The biomarker validation is exemplarily shown for rheumatoid arthritis (RA) on synovial membrane. Cryosections were scanned and analyzed by phantom contouring. Adequate statistical methods allowed the identification of suitable markers and combinations. The fluorescence analysis of the phantoms allowed the discrimination between synovial membrane of RA patients and non-RA control sections by using median fluorescence intensity and the "affected area". As intensity and area are relevant parameters of in vivo imaging (e.g. PET scan) too, the presented method allows emulation of a probable outcome of in vivo imaging, i.e. the binding of the target protein and hence, the validation of the potential of the respective biomarker.

  3. Speckle averaging system for laser raster-scan image projection

    Science.gov (United States)

    Tiszauer, Detlev H.; Hackel, Lloyd A.

    1998-03-17

    The viewers' perception of laser speckle in a laser-scanned image projection system is modified or eliminated by the addition of an optical deflection system that effectively presents a new speckle realization at each point on the viewing screen to each viewer for every scan across the field. The speckle averaging is accomplished without introduction of spurious imaging artifacts.

  4. Evaluation of 3-D laser scanning equipment : 2016 interim report.

    Science.gov (United States)

    2017-05-01

    As a follow-up to ICT Project R27-030, Evaluation of 3-D Laser Scanning, this report provides findings of an evaluation of 3-D laser : scanning equipment to determine the tangible costs versus benefits and the manpower savings realized by using the e...

  5. Development of laser excited atomic fluorescence and ionization methods

    International Nuclear Information System (INIS)

    Winefordner, J.D.

    1991-01-01

    Progress report: May 1, 1988 to December 31, 1991. The research supported by DE-FG05-88ER13881 during the past (nearly) 3 years can be divided into the following four categories: (1) theoretical considerations of the ultimate detection powers of laser fluorescence and laser ionization methods; (2) experimental evaluation of laser excited atomic fluorescence; (3) fundamental studies of atomic and molecular parameters in flames and plasmas; (4) other studies

  6. Laser safety in design of near-infrared scanning LIDARs

    Science.gov (United States)

    Zhu, X.; Elgin, D.

    2015-05-01

    3D LIDARs (Light Detection and Ranging) with 1.5μm nanosecond pulse lasers have been increasingly used in different applications. The main reason for their popularity is that these LIDARs have high performance while at the same time can be made eye-safe. Because the laser hazard effect on eyes or skin at this wavelength region (industrial mining applications. We have incorporated the laser safety requirements in the LIDAR design and conducted laser safety analysis for different operational scenarios. While 1.5μm is normally said to be the eye-safe wavelength, in reality a high performance 3D LIDAR needs high pulse energy, small beam size and high pulse repetition frequency (PRF) to achieve long range, high resolution and high density images. The resulting radiant exposure of its stationary beam could be many times higher than the limit for a Class 1 laser device. Without carefully choosing laser and scanning parameters, including field-of-view, scan speed and pattern, a scanning LIDAR can't be eye- or skin-safe based only on its wavelength. This paper discusses the laser safety considerations in the design of eye-safe scanning LIDARs, including laser pulse energy, PRF, beam size and scanning parameters in two basic designs of scanning mechanisms, i.e. galvanometer based scanner and Risley prism based scanner. The laser safety is discussed in terms of device classification, nominal ocular hazard distance (NOHD) and safety glasses optical density (OD).

  7. Simultaneous Correlative Scanning Electron and High-NA Fluorescence Microscopy

    Science.gov (United States)

    Liv, Nalan; Zonnevylle, A. Christiaan; Narvaez, Angela C.; Effting, Andries P. J.; Voorneveld, Philip W.; Lucas, Miriam S.; Hardwick, James C.; Wepf, Roger A.; Kruit, Pieter; Hoogenboom, Jacob P.

    2013-01-01

    Correlative light and electron microscopy (CLEM) is a unique method for investigating biological structure-function relations. With CLEM protein distributions visualized in fluorescence can be mapped onto the cellular ultrastructure measured with electron microscopy. Widespread application of correlative microscopy is hampered by elaborate experimental procedures related foremost to retrieving regions of interest in both modalities and/or compromises in integrated approaches. We present a novel approach to correlative microscopy, in which a high numerical aperture epi-fluorescence microscope and a scanning electron microscope illuminate the same area of a sample at the same time. This removes the need for retrieval of regions of interest leading to a drastic reduction of inspection times and the possibility for quantitative investigations of large areas and datasets with correlative microscopy. We demonstrate Simultaneous CLEM (SCLEM) analyzing cell-cell connections and membrane protrusions in whole uncoated colon adenocarcinoma cell line cells stained for actin and cortactin with AlexaFluor488. SCLEM imaging of coverglass-mounted tissue sections with both electron-dense and fluorescence staining is also shown. PMID:23409024

  8. Tree Height Growth Measurement with Single-Scan Airborne, Static Terrestrial and Mobile Laser Scanning

    Directory of Open Access Journals (Sweden)

    Yi Lin

    2012-09-01

    Full Text Available This study explores the feasibility of applying single-scan airborne, static terrestrial and mobile laser scanning for improving the accuracy of tree height growth measurement. Specifically, compared to the traditional works on forest growth inventory with airborne laser scanning, two issues are regarded: “Can the new technique characterize the height growth for each individual tree?” and “Can this technique refine the minimum growth-discernable temporal interval further?” To solve these two puzzles, the sampling principles of the three laser scanning modes were first examined, and their error sources against the task of tree-top capturing were also analyzed. Next, the three-year growths of 58 Nordic maple trees (Crimson King for test were intermittently surveyed with one type of laser scanning each time and then analyzed by statistics. The evaluations show that the height growth of each individual tree still cannot be reliably characterized even by single-scan terrestrial laser scanning, and statistical analysis is necessary in this scenario. After Gaussian regression, it is found that the minimum temporal interval with distinguishable tree height growths can be refined into one month based on terrestrial laser scanning, far better than the two years deduced in the previous works based on airborne laser scanning. The associated mean growth was detected to be about 0.12 m. Moreover, the parameter of tree height generally under-estimated by airborne and even mobile laser scanning can be relatively revised by means of introducing static terrestrial laser scanning data. Overall, the effectiveness of the proposed technique is primarily validated.

  9. A laser sheet self-calibration method for scanning PIV

    Science.gov (United States)

    Knutsen, Anna N.; Lawson, John M.; Dawson, James R.; Worth, Nicholas A.

    2017-10-01

    Knowledge of laser sheet position, orientation, and thickness is a fundamental requirement of scanning PIV and other laser-scanning methods. This paper describes the development and evaluation of a new laser sheet self-calibration method for stereoscopic scanning PIV, which allows the measurement of these properties from particle images themselves. The approach is to fit a laser sheet model by treating particles as randomly distributed probes of the laser sheet profile, whose position is obtained via a triangulation procedure enhanced by matching particle images according to their variation in brightness over a scan. Numerical simulations and tests with experimental data were used to quantify the sensitivity of the method to typical experimental error sources and validate its performance in practice. The numerical simulations demonstrate the accurate recovery of the laser sheet parameters over range of different seeding densities and sheet thicknesses. Furthermore, they show that the method is robust to significant image noise and camera misalignment. Tests with experimental data confirm that the laser sheet model can be accurately reconstructed with no impairment to PIV measurement accuracy. The new method is more efficient and robust in comparison with the standard (self-) calibration approach, which requires an involved, separate calibration step that is sensitive to experimental misalignments. The method significantly improves the practicality of making accurate scanning PIV measurements and broadens its potential applicability to scanning systems with significant vibrations.

  10. Maritime Laser Scanning as the Source for Spatial Data

    Directory of Open Access Journals (Sweden)

    Szulwic Jakub

    2015-12-01

    Full Text Available The rapid development of scanning technology, especially mobile scanning, gives the possibility to collect spatial data coming from maritime measurement platforms and autonomous manned or unmanned vehicles. Presented solution is derived from the mobile scanning. However we should keep in mind that the specificity of laser scanning at sea and processing collected data should be in the form acceptable in Geographical Information Systems, especially typical for the maritime needs. At the same time we should be aware that data coming from maritime mobile scanning constitutes a new approach to the describing of maritime environment and brings a new perspective that is completely different than air and terrestrial scanning.

  11. Experimental verification of subthreshold laser therapy using conventional pattern scan laser.

    Directory of Open Access Journals (Sweden)

    Tomoyasu Shiraya

    Full Text Available Leading-edge therapeutic laser technologies are not available at every medical facility; therefore, alternative approaches incorporating novel advances in digital and laser technology into more readily available conventional methods have generated significant research interest. Using a rabbit model, this study investigated whether the algorithm used in the Endpoint Management (EM software system of the latest devices could enable subthreshold laser treatment in conventional retinal tissue laser therapy systems.Two types of devices were used, the PASCAL Streamline 577 and the MC 500-Vixi™, and the laser method was classified into three categories: EM; single-shot using PASCAL with arbitrary energy settings (PSS-SDM; and MC500-VixiTM (VX-SDM, which were performed in eight eyes from four Dutch-Belted rabbits. In EM, 100 mW (100% was set as a landmark, and the laser energy parameters were gradually decreased to 80%, 60%, 50%, 40%, 30%, 20%, and 10%, using a 2 × 3 square pattern. In PSS-SDM and VX-SDM, as control, the laser energy was gradually decreased to 100, 80, 60, 50, 40, 30, 20, and 10 mW. The laser settings were fixed at 200 μm, 20 ms, and a wavelength of 577 μm. To identify and compare the extent of tissue damage at each spot size, optical coherence tomography (OCT and histological findings were used to construct a three-dimensional histopathology image using a confocal laser scanning fluorescence microscope.The spot size at 50% setting on EM was 7183 μm2; PSS-SDM required 50 mW (5503 μm2 to 60 mW (10279 μm2 and VX-SDM required 50 mW (7423 μm2 to create the approximate spot size. Furthermore, at 50 mW of PSS-SDM and VX-SDM, the extent of tissue damage in all three methods was generally in accord with the outer nuclear layer by OCT and inner nuclear layer by histopathological imaging.These findings suggest that it may be possible to perform subthreshold laser therapy using approximations from the EM algorithm.

  12. Confocal retinal imaging using scanning laser opthalmoscopy with annular beams

    NARCIS (Netherlands)

    Vohnsen, Brian; Lochocki, Benjamin; Vela-Garcia, Carmen; Rativa, Diego

    2012-01-01

    The human retina has been imaged in-vivo using scanning laser ophthalmoscopy employing annular incident beams adapted for resolution optimization. The pros and cons of the approach are discussed and the importance of coherence is explored.

  13. Laser Scanning and Simulation at Kennedy Space Center

    Science.gov (United States)

    Kickbusch, Tracey E.

    2012-01-01

    We perform simulations of ground operations leading up launch at Kennedy Space Center and Vandenberg Air Force Base in CA. We use Laser Scanning, Modeling and Simulations to make sure operations are feasible, efficient, and safe.

  14. Diagnostic value of the confocal laser scanning microscopy in vivo

    Directory of Open Access Journals (Sweden)

    A. A. Kubanova

    2015-01-01

    Full Text Available The confocal laser scanning microscopy in vivo is a promising study method to visualize cell structures of epidermis and papillary dermis without affecting the skin integrity, which provides for a resolution and contrast similar to those characteristic of the classical histology examination. Goal. To assess the confocal laser scanning microscopy in vivo (CLSM technique for diagnosing actinic keratosis, psoriasis vulgaris and rosacea vs. the classical histology examination. Study materials. The article describes the results obtained by using the confocal laser scanning microscopy in vivo technique vs. the histology examination in 10 patients with erythematous actinic keratosis, 10 patients with extensive psoriasis and 10 patients with erythematous and papulous rosacea. Results. The article describes diagnostically significant signs of the diseases detected by using the confocal laser scanning microscopy in vivo as well as the potential of this method in terms of diagnosing inflammatory skin diseases.

  15. Influence of laser frequency noise on scanning Fabry-Perot interferometer based laser Doppler velocimetry

    DEFF Research Database (Denmark)

    Rodrigo, Peter John; Pedersen, Christian

    2014-01-01

    n this work, we study the performance of a scanning Fabry-Perot interferometer based laser Doppler velocimeter (sFPILDV) and compare two candidate 1.5 um single-frequency laser sources for the system – a fiber laser (FL) and a semiconductor laser (SL). We describe a straightforward calibration...

  16. Power Measurements for Microvision, Inc., Aircrew Integrated Helmet System Scanning Laser Helmet-Mounted Display

    National Research Council Canada - National Science Library

    Rash, Clarence

    2002-01-01

    ...) technology based on scanning lasers. Under this program, Microvision, Inc., Bothell, Washington, has developed a scanning laser HMD prototype for use with the Aircrew Integrated Helmet System (AIHS...

  17. Injection Seeded Laser for Formaldehyde Differential Fluorescence Lidar

    Science.gov (United States)

    Schwemmer, G.; Yakshin, M.; Prasad, C.; Hanisco, T.; Mylapore, A. R.; Hwang, I. H.; Lee, S.

    2016-01-01

    We describe the design and development of an injection seeded Nd:YVO4 laser for use in a differential fluorescence lidar for measuring atmospheric formaldehyde profiles. A high repetition rate Q-switched laser is modified to accept injection seed input to spectrally narrow and tune the output. The third harmonic output is used to excite formaldehyde (HCHO) fluorescence when tuned to a HCHO absorption line. Spectral confirmation is made with the use of a photoacoustic cell and grating spectrometer.

  18. Remote sensing vegetation status by laser-induced fluorescence

    International Nuclear Information System (INIS)

    Günther, K.P.; Dahn, H.G.; Lüdeker, W.

    1994-01-01

    In November 1989 the EUREKA project LASFLEUR (EU 380) started as an European research effort to investigate the future application of far-field laser-induced plant fluorescence for synoptic, airborne environmental monitoring of vegetation. This report includes a brief introduction in a theoretically approach for the laser-induced fluorescence signals of leaves and their spectral and radiometric behaviour. In addition, a detailed description of the design and realization of the second generation of the far-field fluorescence lidar (DLidaR-2) is given with special regard to the optical and electronical setup, followed by a short explanation of the data processing. The main objectives of the far field measurements are to demonstrate the link between laser-induced fluorescence data and plant physiology and to show the reliability of remote single shot lidar measurements. The data sets include the typical daily cycles of the fluorescence for different global irradiation. As expected from biophysical models, the remotely sensed chlorophyll fluorescence is highly correlated with the carbon fixation rate, while the fluorescence ratio F685 / F730 is only dependent on the chlorophyll concentration. Drought stress measurement of evergreen oaks Quercus pubescens confirm the findings of healthy plants with regard to the fluorescence ratio F685 / F730 while the fluorescence signals of stressed plants show a different behavior than nonstressed plants. Additionally, the corresponding physiological data (porometer and PAM data) are presented. (author)

  19. LASER FLUORESCENCE EEM PROBE FOR CONE PENETROMETER POLLUTION ANALYSIS

    Science.gov (United States)

    A fiber optic LIF (Laser induced fluorescence) EEM (Excitation emission matrix) instrument for CPT deployment has been successfully developed and field tested. The system employs a Nd: YAG laser and Raman shifter as a rugged field portable excitation source. This excitation sou...

  20. Impurity monitoring by laser-induced fluorescence techniques

    International Nuclear Information System (INIS)

    Gelbwachs, J.A.

    1984-01-01

    Laser-induced fluorescence spectroscopy can provide a highly sensitive and selective means of detecting atomic and ionic impurities. Because the photodetector can be physically isolated from the laser-excited region, these techniques can be applied to monitoring in hostile environments. The basic concepts behind fluorescence detection are reviewed. Saturated optical excitation is shown to maximize impurity atom emission yield while mitigating effects of laser intensity fluctuations upon absolute density calibration. Monitoring in high- and low-pressure monitoring environments is compared. Methods to improve detection sensitivity by luminescence background suppression are presented

  1. Applying Terrestrial Laser Scanning for Soil Surface Roughness Assessment

    Directory of Open Access Journals (Sweden)

    Milutin Milenković

    2015-02-01

    Full Text Available Terrestrial laser scanning can provide high-resolution, two-dimensional sampling of soil surface roughness. While previous studies demonstrated the usefulness of these roughness measurements in geophysical applications, questions about the number of required scans and their resolution were not investigated thoroughly. Here, we suggest a method to generate digital elevation models, while preserving the surface’s stochastic properties at high frequencies and additionally providing an estimate of their spatial resolution. We also study the impact of the number and positions of scans on roughness indices’ estimates. An experiment over a smooth and isotropic soil plot accompanies the analysis, where scanning results are compared to results from active triangulation. The roughness measurement conditions for ideal sampling are revisited and updated for diffraction-limited sampling valid for close-range laser scanning over smooth and isotropic soil roughness. Our results show that terrestrial laser scanning can be readily used for roughness assessment on scales larger than 5 cm, while for smaller scales, special processing is required to mitigate the effect of the laser beam footprint. Interestingly, classical roughness parametrization (correlation length, root mean square height (RMSh was not sensitive to these effects. Furthermore, comparing the classical roughness parametrization between one- and four-scan setups shows that the one-scan data can replace the four-scan setup with a relative loss of accuracy below 1% for ranges up to 3 m and incidence angles no larger than 50°, while two opposite scans can replace it over the whole plot. The incidence angle limit for the spectral slope is even stronger and is 40°. These findings are valid for scanning over smooth and isotropic soil roughness.

  2. Nonlinear Laser Fluorescence Spectroscopy of Natural Organic Compounds

    Science.gov (United States)

    Fadeev, Victor V.; Shirshin, Evgeny A.

    Principles of nonlinear laser fluorescence spectroscopy of complicated organic compounds and of the method capable of determining photophysical parameters are considered in this chapter. Special attention is paid to the peculiarities of the method connected with specific photophysical processes in natural organic compounds, especially in proteins, and to the major role of intramolecular energy transfer and presence of localized donor-acceptor pairs (LDAP) of fluorophores within single macromolecules. These facts stimulated the development of models based on the collective states formalism describing fluorescent response of LDAP to pulsed laser excitation. Unique features of the method are illustrated by the example of proteins (proteins with intrinsic fluorescence (HSA, BSA) and fluorescent protein mRFP1) that can be used as fluorescent tags of intracellular processes while their photophysical parameters can be used as the information channel.

  3. HOVE-Wedge-Filtering of Geomorphologic Terrestrial Laser Scan Data

    Directory of Open Access Journals (Sweden)

    Helmut Panholzer

    2018-02-01

    Full Text Available Terrestrial laser scanning has become an important surveying technique in many fields such as natural hazard assessment. To analyse earth surface processes, it is useful to generate a digital terrain model originated from laser scan point cloud data. To determine the terrain surface as precisely as possible, it is often necessary to filter out points that do not represent the terrain surface. Examples are vegetation, vehicles, and animals. In mountainous terrain with a small-structured topography, filtering is very difficult. Here, automatic filtering solutions usually designed for airborne laser scan data often lead to unsatisfactory results. In this work, we further develop an existing approach for automated filtering of terrestrial laser scan data, which is based on the assumption that no other surface point can be located in the area above a direct line of sight between scanner and another measured point. By taking into account several environmental variables and a repetitive calculation method, the modified method leads to significantly better results. The root-mean-square-error (RSME for the same test measurement area could be reduced from 5.284 to 1.610. In addition, a new approach for filtering and interpolation of terrestrial laser scanning data is presented using a grid with horizontal and vertical angular data and the measurement length.

  4. Framework for Bridge Inspection with Laser Scanning

    OpenAIRE

    Truong-Hong, Linh; Falter, Holger; Lennon, Donal; Laefer, Debra F.

    2016-01-01

    For the last two decades, a significant amount research has been developed for collecting data for bridge inspection. Yet, visual investigation with an on-site inspector remains the predominant method; however is the highly subjective and time consuming. Alternatively, terrestrial laser scanner (TLS) can acquire surface details of structures quickly and accurately and is, thus, an emerging means to overcome the shortcomings of direct visual inspection. This paper presents a framework of bridg...

  5. Three-photon fluorescence imaging of melanin with a dual-wedge confocal scanning system

    Science.gov (United States)

    Mega, Yair; Kerimo, Joseph; Robinson, Joseph; Vakili, Ali; Johnson, Nicolette; DiMarzio, Charles

    2012-03-01

    Confocal microscopy can be used as a practical tool in non-invasive applications in medical diagnostics and evaluation. In particular, it is being used for the early detection of skin cancer to identify pathological cellular components and, potentially, replace conventional biopsies. The detection of melanin and its spatial location and distribution plays a crucial role in the detection and evaluation of skin cancer. Our previous work has shown that the visible emission from melanin is strong and can be easily observed with a near-infrared CW laser using low power. This is due to a unique step-wise, (SW) three-photon excitation of melanin. This paper shows that the same SW, 3-photon fluorescence can also be achieved with an inexpensive, continuous-wave laser using a dual-prism scanning system. This demonstrates that the technology could be integrated into a portable confocal microscope for clinical applications. The results presented here are in agreement with images obtained with the larger and more expensive femtosecond laser system used earlier.

  6. Resolution and contrast enhancement in laser scanning microscopy using dark beam imaging.

    Science.gov (United States)

    Dehez, Harold; Piché, Michel; De Koninck, Yves

    2013-07-01

    Laser scanning microscopy allows for three-dimensional imaging of cells with molecular specific labeling. However the spatial resolution of optical microscopy is fundamentally limited by the diffraction of light. In the last two decades many techniques have been introduced to enhance the resolution of laser scanning microscopes. However most of these techniques impose strong constraints on the specimen or rely on complex optical systems. These constraints limit the applicability of resolution improvement to various imaging modalities and sample types. To overcome these limitations, we introduce here a novel approach, which we called Switching LAser Mode (SLAM) microscopy, to enhance resolution and contrast in laser scanning microscopy. SLAM microscopy relies on subtracting images obtained with dark and bright modes, and exploits the smaller dimensions of the dark spot of the azimuthally polarized TE 01 mode. With this approach, resolution is improved by a factor of two in confocal microscopy. The technique is not based on complex nonlinear processes and thus requires laser power similar to that used in conventional imaging, minimizing photo-damage. The flexibility of the approach enables retrofitting in commercial confocal and two-photon microscopes and opens avenues for resolution enhancement in fluorescence-independent microscopy.

  7. A non perturbative optical probe for laser induced fluorescence diagnostics in magnetized plasma

    International Nuclear Information System (INIS)

    Anderegg, F.; Paris, P.J.; Skiff, F.; Good, T.N.; Tran, M.Q.

    1988-01-01

    An 'optical carriage' has been developed to improve plasma access for LIF diganostics. Laser light inducing the fluorescence is transported through an optical fiber to the carriage. A telescope fixed on the carriage collects the plasma fluorescence light and sends it through a fiber bundle to an external PMT. The whole carriage is mounted on rails and can be scanned along and acrosss magnetic field. Wave interferograms and slow rotation of a plasma measured via LIF and optical tagging demonstrate the flexibility of the 'optical carriage'. (author) 4 figs., 8 refs

  8. Using a laser scanning camera for reactor inspection

    International Nuclear Information System (INIS)

    Armour, I.A.; Adrain, R.S.; Klewe, R.C.

    1984-01-01

    Inspection of nuclear reactors is normally carried out using TV or film cameras. There are, however, several areas where these cameras show considerable shortcomings. To overcome these difficulties, laser scanning cameras have been developed. This type of camera can be used for general visual inspection as well as the provision of high resolution video images with high ratio on and off-axis zoom capability. In this paper, we outline the construction and operation of a laser scanning camera and give examples of how it has been used in various power stations, and indicate future potential developments. (author)

  9. Confocal laser scanning microscopy in study of bone calcification

    International Nuclear Information System (INIS)

    Nishikawa, Tetsunari; Kokubu, Mayu; Kato, Hirohito; Imai, Koichi; Tanaka, Akio

    2012-01-01

    Highlights: ► High-magnification images with depth selection, and thin sections were observed using CLSM. ► The direction and velocity of calcification of the bone was observed by administration of 2 fluorescent dyes. ► In dog femora grafted with coral blocks, newly-formed bone was observed in the coral block space with a rough surface. ► Twelve weeks after dental implant was grafted in dog femora, the space between screws was filled with newly-formed bones. - Abstract: Bone regeneration in mandible and maxillae after extraction of teeth or tumor resection and the use of rough surface implants in bone induction must be investigated to elucidate the mechanism of calcification. The calcified tissues are subjected to chemical decalcification or physical grinding to observe their microscopic features with light microscopy and transmission electron microscopy where the microscopic tissue morphology is significantly altered. We investigated the usefulness of confocal laser scanning microscopy (CLSM) for this purpose. After staggering the time of administration of calcein and alizarin red to experimental rats and dogs, rat alveolar bone and dog femur grafted with coral as scaffold or dental implants were observed with CLSM. In rat alveolar bone, the calcification of newly-formed bone and net-like canaliculi was observed at the mesial bone from the roots progressed at the rate of 15 μm/day. In dog femur grafted with coral, newly-formed bones along the space of coral were observed in an orderly manner. In dog femur with dental implants, after 8 weeks, newly-formed bone proceeded along the rough surface of the implants. CLSM produced high-magnification images of newly-formed bone and thin sections were not needed.

  10. Confocal laser scanning microscopy in study of bone calcification

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, Tetsunari, E-mail: tetsu-n@cc.osaka-dent.ac.jp [Department of Oral Pathology, Osaka Dental University, Osaka (Japan); Kokubu, Mayu; Kato, Hirohito [Department of Oral Pathology, Osaka Dental University, Osaka (Japan); Imai, Koichi [Department of Biomaterials, Osaka Dental University, Osaka (Japan); Tanaka, Akio [Department of Oral Pathology, Osaka Dental University, Osaka (Japan)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer High-magnification images with depth selection, and thin sections were observed using CLSM. Black-Right-Pointing-Pointer The direction and velocity of calcification of the bone was observed by administration of 2 fluorescent dyes. Black-Right-Pointing-Pointer In dog femora grafted with coral blocks, newly-formed bone was observed in the coral block space with a rough surface. Black-Right-Pointing-Pointer Twelve weeks after dental implant was grafted in dog femora, the space between screws was filled with newly-formed bones. - Abstract: Bone regeneration in mandible and maxillae after extraction of teeth or tumor resection and the use of rough surface implants in bone induction must be investigated to elucidate the mechanism of calcification. The calcified tissues are subjected to chemical decalcification or physical grinding to observe their microscopic features with light microscopy and transmission electron microscopy where the microscopic tissue morphology is significantly altered. We investigated the usefulness of confocal laser scanning microscopy (CLSM) for this purpose. After staggering the time of administration of calcein and alizarin red to experimental rats and dogs, rat alveolar bone and dog femur grafted with coral as scaffold or dental implants were observed with CLSM. In rat alveolar bone, the calcification of newly-formed bone and net-like canaliculi was observed at the mesial bone from the roots progressed at the rate of 15 {mu}m/day. In dog femur grafted with coral, newly-formed bones along the space of coral were observed in an orderly manner. In dog femur with dental implants, after 8 weeks, newly-formed bone proceeded along the rough surface of the implants. CLSM produced high-magnification images of newly-formed bone and thin sections were not needed.

  11. Laser Induced Fluorescence Diagnostic for the Plasma Couette Experiment

    Science.gov (United States)

    Katz, Noam; Skiff, Fred; Collins, Cami; Weisberg, Dave; Wallace, John; Clark, Mike; Garot, Kristine; Forest, Cary

    2010-11-01

    The Plasma Couette Experiment (PCX) at U. Wisconsin-Madison consists of a rotating high-beta plasma and is well-suited to the study of flow-driven, astrophysically-relevant plasma phenomena. PCX confinement relies on alternating rings of 1kG permanent magnets and the rotation is driven by electrode rings, interspersed between the magnets, which provide an azimuthal ExB. I will discuss the development of a laser-induced fluorescence diagnostic (LIF) to characterize the ion distribution function of argon plasmas in PCX. The LIF system--which will be scanned radially--will be used to calibrate internal Mach probes, as well as to measure the time-resolved velocity profile, ion temperature and density non-perturbatively. These diagnostics will be applied to study the magneto-rotational instability in a plasma, as well as the buoyancy instability thought to be involved in producing the solar magnetic field. This work is supported by NSF and DOE.

  12. Injection Seeded Laser for Formaldehyde Differential Fluorescence Lidar

    Directory of Open Access Journals (Sweden)

    Schwemmer G.

    2016-01-01

    Full Text Available We describe the design and development of an injection seeded Nd:YVO4 laser for use in a differential fluorescence lidar for measuring atmospheric formaldehyde profiles. A high repetition rate Q-switched laser is modified to accept injection seed input to spectrally narrow and tune the output. The third harmonic output is used to excite formaldehyde (HCHO fluorescence when tuned to a HCHO absorption line. Spectral confirmation is made with the use of a photoacoustic cell and grating spectrometer.

  13. Time-resolved laser-induced fluorescence system

    Science.gov (United States)

    Bautista, F. J.; De la Rosa, J.; Gallegos, F. J.

    2006-02-01

    Fluorescence methods are being used increasingly in the measurement of species concentrations in gases, liquids and solids. Laser induced fluorescence is spontaneous emission from atoms or molecules that have been excited by laser radiation. Here we present a time resolved fluorescence instrument that consists of a 5 μJ Nitrogen laser (337.1 nm), a sample holder, a quartz optical fiber, a spectrometer, a PMT and a PC that allows the measurement of visible fluorescence spectra (350-750 nm). Time response of the system is approximately 5 ns. The instrument has been used in the measurement of colored bond paper, antifreeze, diesel, cochineal pigment and malignant tissues. The data acquisition was achieved through computer control of a digital oscilloscope (using General Purpose Interface Bus GPIB) and the spectrometer via serial (RS232). The instrument software provides a graphic interface that lets make some data acquisition tasks like finding fluorescence spectra, and fluorescence lifetimes. The software was developed using the Lab-View 6i graphic programming package and can be easily managed in order to add more functions to it.

  14. Laser induced uranium fluorescence as an analytical method

    International Nuclear Information System (INIS)

    Krutman, I.

    1985-01-01

    A laser induced fluorescence system was developed to measure uranium trace level amounts in aqueous solution with reliable and simple materials and electronics. A nitrogen pulsed laser was built with the storage energy capacitor directly coupled to laser tube electrodes as a transmission line device. This laser operated at 3Hz repetition rate with peak intensity around 21 Kw and temporal width of 4.5 x 10 -9 s. A sample compartment made of rigid PVC and a photomultiplier housing of aluminium were constructed and assembled forming a single integrated device. As a result of this prototype system we made several analytical measurements with U dissolved in nitric acid to obtain a calibration curve. We obtained a straight line from a plot of U concentration versus fluorescence intensity fitted by a least square method that produced a regression coefficient of 0.994. The lower limit of U determination was 30 ppb -+ 3.5%. (Author) [pt

  15. In vivo visualization of microneedle conduits in human skin using laser scanning microscopy

    International Nuclear Information System (INIS)

    Bal, S; Kruithof, A C; Bouwstra, J; Liebl, H; Tomerius, M; Lademann, J; Meinke, M

    2010-01-01

    Solid microneedles enhance the penetration of drugs into the viable skin but little is known about the geometry of the conduits in vivo. Therefore, laser scanning microscopy was used to visualize the conduits of a microneedle system with needles at a length of 300 μm in 6 healthy subjects over a period of time. The model drug, a fluorescent dye was applied before and after piercing. Laser scanning microscopy was evaluated as being an excellent method to monitor the geometry and closure of the conduits over time. The used microneedle system was evaluated as suitable to enhance the transport of model drugs into the viable epidermis without bleeding and a short closure time of the conduits at the skin surface

  16. In vivo visualization of microneedle conduits in human skin using laser scanning microscopy

    Science.gov (United States)

    Bal, S.; Kruithof, A. C.; Liebl, H.; Tomerius, M.; Bouwstra, J.; Lademann, J.; Meinke, M.

    2010-03-01

    Solid microneedles enhance the penetration of drugs into the viable skin but little is known about the geometry of the conduits in vivo. Therefore, laser scanning microscopy was used to visualize the conduits of a microneedle system with needles at a length of 300 μm in 6 healthy subjects over a period of time. The model drug, a fluorescent dye was applied before and after piercing. Laser scanning microscopy was evaluated as being an excellent method to monitor the geometry and closure of the conduits over time. The used microneedle system was evaluated as suitable to enhance the transport of model drugs into the viable epidermis without bleeding and a short closure time of the conduits at the skin surface.

  17. Impact of oxygen chemistry on the emission and fluorescence spectroscopy of laser ablation plumes

    Science.gov (United States)

    Hartig, K. C.; Brumfield, B. E.; Phillips, M. C.; Harilal, S. S.

    2017-09-01

    Oxygen present in the ambient gas medium may affect both laser-induced breakdown spectroscopy (LIBS) and laser-induced fluorescence (LIF) emission through a reduction of emission intensity and persistence. In this study, an evaluation is made on the role of oxygen in the ambient environment under atmospheric pressure conditions in LIBS and laser ablation (LA)-LIF emission. To generate plasmas, 1064 nm, 10 ns pulses were focused on an aluminum alloy sample. LIF was performed by frequency scanning a CW laser over the 396.15 nm (3s24s 2S1/2 → 3s23p 2P°3/2) Al I transition. Time-resolved emission and fluorescence signals were recorded to evaluate the variation in emission intensity caused by the presence of oxygen. The oxygen partial pressure (po) in the atmospheric pressure environment using N2 as the makeup gas was varied from 0 to 400 Torr O2. 2D-fluorescence spectroscopy images were obtained for various oxygen concentrations for simultaneous evaluation of the emission and excitation spectral features. Results showed that the presence of oxygen in the ambient environment reduces the persistence of the LIBS and LIF emission through an oxidation process that depletes the density of atomic species within the resulting laser-produced plasma (LPP) plume.

  18. Scanning laser vibrometer measurement of guided waves in rails

    CSIR Research Space (South Africa)

    Loveday, PW

    2012-04-01

    Full Text Available from the measured frequency responses by using a pseudo-inverse technique and mode shape information computed from a semi-analytical finite element model. Scanning laser measurements were performed in the field at distances of 10m and 500m from a...

  19. From Point Cloud to Textured Model, the Zamani Laser Scanning ...

    African Journals Online (AJOL)

    The paper describes the stages of the laser scanning pipeline from data acquisition to the final 3D computer model based on experiences gained during the ongoing creation of data for the African Cultural Heritage Sites and Landscapes database. The various processes are briefly discussed and challenges are highlighted ...

  20. Single scan vector prediction in selective laser melting

    NARCIS (Netherlands)

    Wits, Wessel Willems; Bruins, R.; Terpstra, L.; Huls, R.A.; Geijselaers, Hubertus J.M.

    2015-01-01

    In selective laser melting (SLM) products are built by melting layers of metal powder successively. Optimal process parameters are usually obtained by scanning single vectors and subsequently determining which settings lead to a good compromise between product density and build speed. This paper

  1. USE OF LASER SCANNING FOR CULTURAL HERITAGE DOCUMENTATION

    Directory of Open Access Journals (Sweden)

    Gulhan BENLI

    2013-01-01

    Full Text Available In terms of raising an awareness of the historical, national and cultural properties in our country and ensuring a transfer of information to posterity, it is of vital importance to take inventory of the cultural and natural real properties located in protected sites. Many fields, such as medical science, construction, ground engineering, geodetic engineering, and architecture, make use of the present-day laser scanning technology. Even if contemporary and current scientific methods are used for the inventory and documentation studies related to cultural and natural real properties in the PROTECTED SITES in the field of architecture; acquiring data of the entirety of a protected site using these methods is a time consuming process. Among the scientific methods applied, laser scanning technology has the utmost importance in the latest years. The laser scanning devices for the detection of cultural, natural and historical properties in archeological, historical, urban or mixed protected sites in Turkey, eliminate challenges such as the enormity of sites, the difficulty of working in the sites, intense work hours, and the necessity of having a thorough knowledge of the site. In the scope of this study, the usage, application, facilities, advantages and attainments of geodetic laser scanning systems in conducting surveys on facade, street or avenue silhouettes in the protected sites, where historical buildings within field of architecture are widespread, will be examined.

  2. COMPARISON OF RETINAL PATHOLOGY VISUALIZATION IN MULTISPECTRAL SCANNING LASER IMAGING.

    Science.gov (United States)

    Meshi, Amit; Lin, Tiezhu; Dans, Kunny; Chen, Kevin C; Amador, Manuel; Hasenstab, Kyle; Muftuoglu, Ilkay Kilic; Nudleman, Eric; Chao, Daniel; Bartsch, Dirk-Uwe; Freeman, William R

    2018-03-16

    To compare retinal pathology visualization in multispectral scanning laser ophthalmoscope imaging between the Spectralis and Optos devices. This retrospective cross-sectional study included 42 eyes from 30 patients with age-related macular degeneration (19 eyes), diabetic retinopathy (10 eyes), and epiretinal membrane (13 eyes). All patients underwent retinal imaging with a color fundus camera (broad-spectrum white light), the Spectralis HRA-2 system (3-color monochromatic lasers), and the Optos P200 system (2-color monochromatic lasers). The Optos image was cropped to a similar size as the Spectralis image. Seven masked graders marked retinal pathologies in each image within a 5 × 5 grid that included the macula. The average area with detected retinal pathology in all eyes was larger in the Spectralis images compared with Optos images (32.4% larger, P images. Spectralis tricolor multispectral scanning laser ophthalmoscope imaging had higher rate of pathology detection primarily because of better epiretinal membrane and retinal hemorrhage visualization compared with Optos bicolor multispectral scanning laser ophthalmoscope imaging.

  3. Laser induced fluorescence imaging system for localization of nasopharyngeal carcinoma

    Science.gov (United States)

    Liu, Lina; Xie, Shusen

    2007-11-01

    A laser induced fluorescence imaging system for localization of Nasopharyngeal Carcinoma is developed. In this fluorescence imaging system, the fluorescence intensity with information of detected objection is gained by an image intensifier, which makes color information of the fluorescence image eliminated and the result is a monochrome image of the fluorescence with thermally induced noise. The monochrome fluorescence image is sent to a CCD and captured by an image board, which is controlled by a computer. Image processing is carried out to improve the image quality and therefore improve the system's ability to differentiate carcinomas from normal tissue. Gaussian smoothing is implemented in order to reduce the noise. Image binarizing process is realized to obtain an optimal threshold of the image. Image pixels with grey value below this threshold are assigned as diseased and those above are normal. A pseudo color processing is then accomplished to get better visual perception and understanding of the image, greatly increasing the detail resolution of the grey image. The processed image is then displayed on the screen of the computer in real time. The real time laser induced fluorescence imaging system with the image processing methods developed is efficient for localization of the nasopharyngeal carcinoma.

  4. Introduction of an ultrathin and flexible laser scanning endoscope for color imaging and integrated PDD and future PDT

    Science.gov (United States)

    Seibel, Eric J.; Kenerson, Heidi L.; Lee, Cameron M.; Melville, C. David; Johnston, Richard S.; Yeung, Raymond S.

    2009-06-01

    The scanning fiber endoscope (SFE), an ultrathin laser scanning endoscope capable of producing 500-line color images at 30-Hz frame rate, has been developed at the University of Washington. The SFE probe is a 1-mm diameter by 9-mm long rigid scanner at the tip of a highly flexible and robust tether (minimum bend radius technologies have suffered from reduced image quality and fragility, such as imaging the peripheral airways and bile duct. The scanning engine of the SFE allows for laser-based imaging and potential applications of pixel-accurate therapy in remote regions of the body. In this study, the standard SFE operation has been tailored to create widefield fluorescence images for photodynamic detection. A kidney with renal cell carcinoma was excised from an Eker rat after post-mortem in situ perfusion with 0.4 mM hypericin. The 442-nm blue and 532-nm green laser illumination sources were used for both standard reflectance imaging and fluorescence excitation, while the red 635- nm illumination was disabled. Red detection signal gain was increased to amplify the red fluorescence signal from the photomultiplier tube and within the computer image display. Results show green and blue reflectance images overlaid with red fluorescence signal in tumor regions of the kidney. These imaging capabilities portend future adoption of laser-based SFE imaging for real-time PDD.

  5. Circumvention of fluorophore photobleaching in fluorescence fluctuation experiments: a beam scanning approach.

    Science.gov (United States)

    Satsoura, Dmitri; Leber, Brian; Andrews, David W; Fradin, Cécile

    2007-04-23

    Photobleaching is a fluorophore-damaging process that commonly afflicts single-molecule fluorescence studies. It becomes an especially severe problem in fluorescence fluctuation experiments when studying slowly diffusing particles. One way to circumvent this problem is to use beam scanning to decrease the residence time of the fluorophores in the excitation volume. We report a systematic study of the effects of circular beam scanning on the photobleaching of fluorescent particles as observed in single-photon excitation fluorescence fluctuation experiments. We start by deriving a simple expression relating the average detected fluorescence to the photobleaching cross section of the fluorophores. We then perform numerical calculations of the spatial distribution of fluorescent particles in order to understand under which conditions beam scanning can prevent the formation of a photobleaching hole. To support these predictions, we show experimental results obtained for large unilamellar vesicles containing a small amount of the fluorescent lipophilic tracer DiD. We establish the required scanning radius and frequency range in order to obtain sufficient reduction of the photobleaching effect for that system. From the detected increase in fluorescence upon increase in scanning speed, we estimate the photobleaching cross section of DiD.

  6. Control Measurements of Crane Rails Performed by Terrestrial Laser Scanning.

    Science.gov (United States)

    Kregar, Klemen; Možina, Jan; Ambrožič, Tomaž; Kogoj, Dušan; Marjetič, Aleš; Štebe, Gašper; Savšek, Simona

    2017-07-20

    This article presents a method for measuring the geometry of crane rails with terrestrial laser scanning (TLS). Two sets of crane rails were divided into segments, their planes were adjusted, and the characteristic rail lines were defined. We used their profiles to define the positional and altitude deviations of the rails, the span and height difference between the two rails, and we also verified that they complied with the Eurocode 3 standard. We tested the method on crane rails at the hydroelectric power plant in Krško and the thermal power plant in Brestanica. We used two scanning techniques: "pure" TLS (Riegel VZ-400) and "hybrid" TLS (Leica MS50) scanning. This article's original contribution lies in the detailed presentation of the computations used to define the characteristic lines of the rails without using the numeric procedures from existing software packages. We also analysed the influence of segment length and point density on the rail geometry results, and compared the two laser scanning techniques. We also compared the results obtained by terrestrial laser scanning with the results obtained from the classic polar method, which served as a reference point for its precision.

  7. A fluorescent screen + CCD system for quality assurance of therapeutic scanned ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Takeshita, E., E-mail: eriuli@nirs.go.jp [National Institute of Radiological Sciences, Chiba (Japan); Furukawa, T., E-mail: t_furu@nirs.go.jp [National Institute of Radiological Sciences, Chiba (Japan); Inaniwa, T., E-mail: taku@nirs.go.jp [National Institute of Radiological Sciences, Chiba (Japan); Sato, S., E-mail: shin_s@nirs.go.jp [National Institute of Radiological Sciences, Chiba (Japan); Himukai, T., E-mail: himukai@nirs.go.jp [National Institute of Radiological Sciences, Chiba (Japan); Shirai, T., E-mail: t_shirai@nirs.go.jp [National Institute of Radiological Sciences, Chiba (Japan); Noda, K., E-mail: noda_k@nirs.go.jp [National Institute of Radiological Sciences, Chiba (Japan)

    2011-12-15

    A fluorescent screen + a charge coupled device (CCD) system were developed to verify the performance of scanned ion beams at the HIMAC. The fluorescent light from the screen is observed by the CCD camera. Two-dimensional fields, produced by the scanning process, i.e., the position and the size of the beam for each scan, represent of the important issues in scanning irradiation. In the developed system, the two-dimensional relative fluence and the flatness of the irradiation field were measured in a straightforward technique from the luminance distribution on the screen. The position and the size of the beams were obtained from centroid computation results of the brightness. By the good sensitivity and spatial resolution of the fluorescent screen + CCD system, the scanned ion beams were verified as the measurements at the HIMAC prototype scanning system.

  8. A fluorescent screen + CCD system for quality assurance of therapeutic scanned ion beams

    Science.gov (United States)

    Takeshita, E.; Furukawa, T.; Inaniwa, T.; Sato, S.; Himukai, T.; Shirai, T.; Noda, K.

    2011-12-01

    A fluorescent screen + a charge coupled device (CCD) system were developed to verify the performance of scanned ion beams at the HIMAC. The fluorescent light from the screen is observed by the CCD camera. Two-dimensional fields, produced by the scanning process, i.e., the position and the size of the beam for each scan, represent of the important issues in scanning irradiation. In the developed system, the two-dimensional relative fluence and the flatness of the irradiation field were measured in a straightforward technique from the luminance distribution on the screen. The position and the size of the beams were obtained from centroid computation results of the brightness. By the good sensitivity and spatial resolution of the fluorescent screen + CCD system, the scanned ion beams were verified as the measurements at the HIMAC prototype scanning system.

  9. Plasma erosion rate diagnostics using laser-induced fluorescence

    Science.gov (United States)

    Gaeta, C. J.; Turley, R. S.; Matossian, J. N.; Beattie, J. R.; Williamson, W. S.

    1992-01-01

    An optical technique for measuring the sputtering rate of a molybdenum surface immersed in a xenon plasma has been developed and demonstrated. This approach, which may be useful in real-time wear diagnostics for ion thrusters, relies on laser-induced fluorescence to determine the density of sputtered molybdenum atoms.

  10. Laser-induced fluorescence of oral mucosa cancer

    Science.gov (United States)

    Jaliashvili, Z. V.; Medoidze, T. D.; Melikishvili, Z. G.; Gogilashvili, K. T.

    2017-10-01

    The laser-induced fluorescence (LIF) spectra have been measured for cancer-infused and control mice mucosa tissues. It was established that there is quite a difference between their LIF spectral shapes. These spectral shapes are used to express the diagnostic of different states of tissues: from normal to cancer.

  11. Molecular Iodine Fluorescence Using a Green Helium-Neon Laser

    Science.gov (United States)

    Williamson, J. Charles

    2011-01-01

    Excitation of molecular iodine vapor with a green (543.4 nm) helium-neon laser produces a fluorescence spectrum that is well suited for the upper-level undergraduate physical chemistry laboratory. Application of standard evaluation techniques to the spectrum yields ground electronic-state molecular parameters in good agreement with literature…

  12. Design of remote laser-induced fluorescence system's acquisition circuit

    Science.gov (United States)

    Wang, Guoqing; Lou, Yue; Wang, Ran; Yan, Debao; Li, Xin; Zhao, Xin; Chen, Dong; Zhao, Qi

    2017-10-01

    Laser-induced fluorescence system(LIfS) has been found its significant application in identifying one kind of substance from another by its properties even it's thimbleful, and becomes useful in plenty of fields. Many superior works have reported LIfS' theoretical analysis , designs and uses. However, the usual LIPS is always constructed in labs to detect matter quite closely, for the system using low-power laser as excitation source and charge coupled device (CCD) as detector. Promoting the detectivity of LIfS is of much concern to spread its application. Here, we take a high-energy narrow-pulse laser instead of commonly used continuous wave laser to operate sample, thus we can get strong fluorescent. Besides, photomultiplier (PMT) with high sensitivity is adopted in our system to detect extremely weak fluorescence after a long flight time from the sample to the detector. Another advantage in our system, as the fluorescence collected into spectroscopy, multiple wavelengths of light can be converted to the corresponding electrical signals with the linear array multichannel PMT. Therefore, at the cost of high-powered incentive and high-sensitive detector, a remote LIFS is get. In order to run this system, it is of importance to turn light signal to digital signal which can be processed by computer. The pulse width of fluorescence is deeply associated with excitation laser, at the nanosecond(ns) level, which has a high demand for acquisition circuit. We design an acquisition circuit including, I/V conversion circuit, amplifying circuit and peak-holding circuit. The simulation of circuit shows that peak-holding circuit can be one effective approach to reducing difficulty of acquisition circuit.

  13. Fluorescence and gain predictions in laser dye mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Ali, M.; Ahmed, S.A.; Mitwally, K. (CUNY City College, Department of Electrical Engineering, Institute for Ultrafast Spectroscopy and Lasers, New York, New York 10031 (US))

    1989-09-01

    Radiative energy transfer in three different laser dye mixtures composed of (1) dichlorofluorescein (donor) and DODC (acceptor), (2) dichlorofluorescein (donor) and RhB (acceptor), and (3) coumarine (donor) and RhB (acceptor) have been studied under steady state excitation conditions. Analytical expressions have been developed to predict steady state fluorescence and hence gain line shape of laser dye mixtures using computer simulation. The theoretical predictions derived are generally in excellent agreement with experimental results, which confirm that at the mixture concentrations needed for lasing, radiative transfer is the dominant energy transfer mechanism. The method developed is effective and practical for predicting laser gain lineshapes (and hence tunability) as well as predicting fluorescence emission spectra of dye mixtures.

  14. Polarization contrast in fluorescence scanning near-field optical microscopy in reflection

    NARCIS (Netherlands)

    Jalocha, A.; Jalocha, A.; van Hulst, N.F.

    1995-01-01

    Polarization contrast is presented in fluorescence images of a Langmuir-Blodgett monolayer obtained with a scanning near-field optical microscope operated in reflection. A tapered optical fiber is used both to excite and to collect the fluorescence. The lateral resolution in the reflection

  15. Laser Ultrasound Spectroscopy Scanning for 3D Printed Parts

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Guendalyn Kendra [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-04

    One of the challenges of additive manufacturing is quality control due to the possibility of unseen flaws in the final product. The current methods of inspection are lacking in detail, too slow for practical use, or unable to validate internal structure. This report examines the use of laser ultrasound spectroscopy in layer by layer scans of 3D printed parts as they are created. The result is fast and detailed quality control. An additional advantage of this method is the ability to cancel a print as soon as a defect is detected, therefore saving materials and time. This technique, though simple in concept, has been a challenge to implement. I discuss tweaking the 3D printer configuration, and finding the optimal settings for laser scanning small parts made of ABS plastic, as well as the limits of how small of a detail the laser can detect. These settings include the frequency of the ultrasonic transducer, the speed of the laser, and the distance from the laser to the part.

  16. Contribution of confocal laser scanning microscopy in deciphering biofilm tridimensional structure and reactivity.

    Science.gov (United States)

    Bridier, Arnaud; Briandet, Romain

    2014-01-01

    Confocal laser scanning microscopy (CLSM) became in last years an invaluable technique to study biofilms since it enables researchers to explore noninvasively the dynamic architecture and the reactivity of these biological edifices. The constant development of fluorescent markers and genetic tools along with the improvement of spatial, spectral, and temporal resolution of imaging facilities offers new opportunities to better decipher microbial biofilm properties. In this contribution, we proposed to describe the contribution of CLSM to the study of biofilm architecture and reactivity throughout two different illustrative approaches.

  17. Forensic analysis of laser printed ink by X-ray fluorescence and laser-excited plume fluorescence.

    Science.gov (United States)

    Chu, Po-Chun; Cai, Bruno Yue; Tsoi, Yeuk Ki; Yuen, Ronald; Leung, Kelvin S Y; Cheung, Nai-Ho

    2013-05-07

    We demonstrated a minimally destructive two-tier approach for multielement forensic analysis of laser-printed ink. The printed document was first screened using a portable-X-ray fluorescence (XRF) probe. If the results were not conclusive, a laser microprobe was then deployed. The laser probe was based on a two-pulse scheme: the first laser pulse ablated a thin layer of the printed ink; the second laser pulse at 193 nm induced multianalytes in the desorbed ink to fluoresce. We analyzed four brands of black toners. The toners were printed on paper in the form of patches or letters or overprinted on another ink. The XRF probe could sort the four brands if the printed letters were larger than font 20. It could not tell the printing sequence in the case of overprints. The laser probe was more discriminatory; it could sort the toner brands and reveal the overprint sequence regardless of font size while the sampled area was not visibly different from neighboring areas even under the microscope. In terms of general analytical performance, the laser probe featured tens of micrometer lateral resolution and tens to hundreds of nm depth resolution and atto-mole mass detection limits. It could handle samples of arbitrary size and shape and was air compatible, and no sample pretreatment was necessary. It will prove useful whenever high-resolution and high sensitivity 3D elemental mapping is required.

  18. A portable confocal hyperspectral microscope without any scan or tube lens and its application in fluorescence and Raman spectral imaging

    Science.gov (United States)

    Li, Jingwei; Cai, Fuhong; Dong, Yongjiang; Zhu, Zhenfeng; Sun, Xianhe; Zhang, Hequn; He, Sailing

    2017-06-01

    In this study, a portable confocal hyperspectral microscope is developed. In traditional confocal laser scanning microscopes, scan lens and tube lens are utilized to achieve a conjugate relationship between the galvanometer and the back focal plane of the objective, in order to achieve a better resolution. However, these lenses make it difficult to scale down the volume of the system. In our portable confocal hyperspectral microscope (PCHM), the objective is placed directly next to the galvomirror. Thus, scan lens and tube lens are not included in our system and the size of this system is greatly reduced. Furthermore, the resolution is also acceptable in many biomedical and food-safety applications. Through reducing the optical length of the system, the signal detection efficiency is enhanced. This is conducive to realizing both the fluorescence and Raman hyperspectral imaging. With a multimode fiber as a pinhole, an improved image contrast is also achieved. Fluorescent spectral images for HeLa cells/fingers and Raman spectral images of kumquat pericarp are present. The spectral resolution and spatial resolutions are about 0.4 nm and 2.19 μm, respectively. These results demonstrate that this portable hyperspectral microscope can be used in in-vivo fluorescence imaging and in situ Raman spectral imaging.

  19. Optics designs and system MTF for laser scanning displays

    Science.gov (United States)

    Urey, Hakan; Nestorovic, Ned; Ng, Baldwin S.; Gross, Abraham A.

    1999-07-01

    The Virtual Retinal DisplayTM (VRDTM) technology is a new display technology being developed at Microvision Inc. The displayed image is scanned onto the viewer's retina using low- power red, green, and blue light sources. Microvision's proprietary miniaturized scanner designs make VRD system very well suited for head-mounted displays. In this paper we discuss some of the advantages of the VRD technology, various ocular designs for HMD and other applications, and details of constructing a system MTF budget for laser scanning systems that includes electronics, modulators, scanners, and optics.

  20. Analysis of Indium Tin Oxide Film Using Argon Fluroide (ArF) Laser-Excited Atomic Fluorescence of Ablated Plumes.

    Science.gov (United States)

    Ho, Sut Kam; Garcia, Dario Machado

    2017-04-01

    A two-pulse laser-excited atomic fluorescence (LEAF) technique at 193 nm wavelength was applied to the analysis of indium tin oxide (ITO) layer on polyethylene terephthalate (PET) film. Fluorescence emissions from analytes were induced from plumes generated by first laser pulse. Using this approach, non-selective LEAF can be accomplished for simultaneous multi-element analysis and it overcomes the handicap of strict requirement for laser excitation wavelength. In this study, experimental conditions including laser fluences, times for gating and time delay between pulses were optimized to reveal high sensitivity with minimal sample destruction and penetration. With weak laser fluences of 100 and 125 mJ/cm 2 for 355 and 193 nm pulses, detection limits were estimated to be 0.10% and 0.43% for Sn and In, respectively. In addition, the relation between fluorescence emissions and number of laser shots was investigated; reproducible results were obtained for Sn and In. It shows the feasibility of depth profiling by this technique. Morphologies of samples were characterized at various laser fluences and number of shots to examine the accurate penetration. Images of craters were also investigated using scanning electron microscopy (SEM). The results demonstrate the imperceptible destructiveness of film after laser shot. With such weak laser fluences and minimal destructiveness, this LEAF technique is suitable for thin-film analysis.

  1. Semantic Labelling of Road Furniture in Mobile Laser Scanning Data

    Science.gov (United States)

    Li, F.; Oude Elberink, S.; Vosselman, G.

    2017-09-01

    Road furniture semantic labelling is vital for large scale mapping and autonomous driving systems. Much research has been investigated on road furniture interpretation in both 2D images and 3D point clouds. Precise interpretation of road furniture in mobile laser scanning data still remains unexplored. In this paper, a novel method is proposed to interpret road furniture based on their logical relations and functionalities. Our work represents the most detailed interpretation of road furniture in mobile laser scanning data. 93.3 % of poles are correctly extracted and all of them are correctly recognised. 94.3 % of street light heads are detected and 76.9 % of them are correctly identified. Despite errors arising from the recognition of other components, our framework provides a promising solution to automatically map road furniture at a detailed level in urban environments.

  2. SEMANTIC LABELLING OF ROAD FURNITURE IN MOBILE LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    F. Li

    2017-09-01

    Full Text Available Road furniture semantic labelling is vital for large scale mapping and autonomous driving systems. Much research has been investigated on road furniture interpretation in both 2D images and 3D point clouds. Precise interpretation of road furniture in mobile laser scanning data still remains unexplored. In this paper, a novel method is proposed to interpret road furniture based on their logical relations and functionalities. Our work represents the most detailed interpretation of road furniture in mobile laser scanning data. 93.3 % of poles are correctly extracted and all of them are correctly recognised. 94.3 % of street light heads are detected and 76.9 % of them are correctly identified. Despite errors arising from the recognition of other components, our framework provides a promising solution to automatically map road furniture at a detailed level in urban environments.

  3. Evaluation of microvision SD2500 scanning laser display

    Science.gov (United States)

    Harding, Thomas H.; Rash, Clarence E.; Dennis, Scott J.

    2006-05-01

    Microvision's Spectrum TM SD2500 is a candidate technology for the Modular Integrated Helmet Display System (MIHDS)program. This HMD design is intended to provide a full-color, see-through, daylight and night-readable, moderate-resolution (800X600 pixels) display. The employed technology is that of scanning lasers. This paper presents the testing results for the latest version of this prototype system.

  4. Confocal scanning laser ophthalmoscopy in glaucoma diagnosis and management.

    Science.gov (United States)

    Alexandrescu, C; Dascalu, A M; Panca, A; Sescioreanu, A; Mitulescu, C; Ciuluvica, R; Voinea, L; Celea, C

    2010-01-01

    The early diagnosis and detection of progression are two key-elements in the actual management of glaucoma. The current opinion in clinical practice is to quantify the structural damage for a better follow-up of the patient and the standardization of the results. The present review is a concise survey of literature covering the period of 1990-2010, documenting the evidence-based role of confocal scanning laser ophthalmoscopy in glaucoma diagnosis and management.

  5. Modeling 3D Objects for Navigation Purposes Using Laser Scanning

    Directory of Open Access Journals (Sweden)

    Cezary Specht

    2016-07-01

    Full Text Available The paper discusses the creation of 3d models and their applications in navigation. It contains a review of available methods and geometric data sources, focusing mostly on terrestrial laser scanning. It presents detailed description, from field survey to numerical elaboration, how to construct accurate model of a typical few storey building as a hypothetical reference in complex building navigation. Hence, the paper presents fields where 3d models are being used and their potential new applications.

  6. scanning speed influence on the physical properties of laser metal

    African Journals Online (AJOL)

    user

    2017-01-01

    Jan 1, 2017 ... The most commonly used aerospace titanium alloy, Ti6Al4V, was deposited on Ti6Al4V plate of dimension 72 x 72 x5mm. The laser power of 3 kW, powder flow rate of 1.44 g/min and gas flow rate of 4 l/min were used throughout the deposition process. The transverse/ scanning speed was varied between ...

  7. Comparison of in vivo and ex vivo laser scanning microscopy and multiphoton tomography application for human and porcine skin imaging

    Energy Technology Data Exchange (ETDEWEB)

    Darvin, M E; Richter, H; Zhu, Y J; Meinke, M C; Knorr, F; Lademann, J [Center of Experimental and Applied Cutaneous Physiology, Department of Dermatology, Venerology and Allergology, Charité - Universitätsmedizin Berlin (Germany); Gonchukov, S A [National Research Nuclear University ' ' MEPhI' ' (Russian Federation); Koenig, K [JenLab GmbH, Schillerstr. 1, 07745 Jena (Germany)

    2014-07-31

    Two state-of-the-art microscopic optical methods, namely, confocal laser scanning microscopy in the fluorescence and reflectance regimes and multiphoton tomography in the autofluorescence and second harmonic generation regimes, are compared for porcine skin ex vivo and healthy human skin in vivo. All skin layers such as stratum corneum (SC), stratum spinosum (SS), stratum basale (SB), papillary dermis (PD) and reticular dermis (RD) as well as transition zones between these skin layers are measured noninvasively at a high resolution, using the above mentioned microscopic methods. In the case of confocal laser scanning microscopy (CLSM), measurements in the fluorescence regime were performed by using a fluorescent dye whose topical application on the surface is well suited for the investigation of superficial SC and characterisation of the skin barrier function. For investigations of deeply located skin layers, such as SS, SB and PD, the fluorescent dye must be injected into the skin, which markedly limits fluorescence measurements using CLSM. In the case of reflection CLSM measurements, the obtained results can be compared to the results of multiphoton tomography (MPT) for all skin layers excluding RD. CLSM cannot distinguish between dermal collagen and elastin measuring their superposition in the RD. By using MPT, it is possible to analyse the collagen and elastin structures separately, which is important for the investigation of anti-aging processes. The resolution of MPT is superior to CLSM. The advantages and limitations of both methods are discussed and the differences and similarities between human and porcine skin are highlighted. (laser biophotonics)

  8. Calibration technology in application of robot-laser scanning system

    Science.gov (United States)

    Ren, YongJie; Yin, ShiBin; Zhu, JiGui

    2012-11-01

    A system composed of laser sensor and 6-DOF industrial robot is proposed to obtain complete three-dimensional (3-D) information of the object surface. Suitable for the different combining ways of laser sensor and robot, a new method to calibrate the position and pose between sensor and robot is presented. By using a standard sphere with known radius as a reference tool, the rotation and translation matrices between the laser sensor and robot are computed, respectively in two steps, so that many unstable factors introduced in conventional optimization methods can be avoided. The experimental results show that the accuracy of the proposed calibration method can be achieved up to 0.062 mm. The calibration method is also implemented into the automated robot scanning system to reconstruct a car door panel.

  9. A positioning free calibration method for mobile laser scanning applications

    Directory of Open Access Journals (Sweden)

    R. Le Scouarnec

    2013-10-01

    Full Text Available Mobile laser scanning are likely to find more and more applications for high density 3D environmental data. A mobile laser scanning system is composed by three subsystems: a GNSS (Global Navigation Satellite System that provides position information, an INS (Inertial Navigation System for attitude determination, and a LiDAR (Light Detection And Ranging. The accuracy of the geolocated LiDAR returns depends on the accuracy of each instrument but also on the bore-sighting parameters and the lever arms between the instruments. Indeed, an imperfect calibration may lead to systematic errors. Calibration may then become the limiting factor of Terrestrial Laser scanning if it is not tackled seriously. Moreover [Ø], it is important to have a reliable value of the calibration precision. This paper presents a new positioning free procedure for the estimation of the LiDAR bore-sighting parameters. Since this method is static, lever arms do not affect the boresight calibration and positioning is not required. That makes the methodology immune to GPS errors. Finally, since it is based on a rigorous mathematical model, it can provide a reliable boresight quality factor. First, the boresight determination problem is explained and existing calibration procedures are introduced. After having explained their drawbacks, a new procedure that tries to overcome these limitations is described. Tests from simulations and real datasets are also presented to illustrate our approach.

  10. Terrestrial laser scanning in monitoring of anthropogenic objects

    Science.gov (United States)

    Zaczek-Peplinska, Janina; Kowalska, Maria

    2017-12-01

    The registered xyz coordinates in the form of a point cloud captured by terrestrial laser scanner and the intensity values (I) assigned to them make it possible to perform geometric and spectral analyses. Comparison of point clouds registered in different time periods requires conversion of the data to a common coordinate system and proper data selection is necessary. Factors like point distribution dependant on the distance between the scanner and the surveyed surface, angle of incidence, tasked scan's density and intensity value have to be taken into consideration. A prerequisite for running a correct analysis of the obtained point clouds registered during periodic measurements using a laser scanner is the ability to determine the quality and accuracy of the analysed data. The article presents a concept of spectral data adjustment based on geometric analysis of a surface as well as examples of geometric analyses integrating geometric and physical data in one cloud of points: cloud point coordinates, recorded intensity values, and thermal images of an object. The experiments described here show multiple possibilities of usage of terrestrial laser scanning data and display the necessity of using multi-aspect and multi-source analyses in anthropogenic object monitoring. The article presents examples of multisource data analyses with regard to Intensity value correction due to the beam's incidence angle. The measurements were performed using a Leica Nova MS50 scanning total station, Z+F Imager 5010 scanner and the integrated Z+F T-Cam thermal camera.

  11. Cellular scanning strategy for selective laser melting: Generating reliable, optimized scanning paths and processing parameters

    DEFF Research Database (Denmark)

    Mohanty, Sankhya; Hattel, Jesper Henri

    2015-01-01

    method based uncertainty and reliability analysis. The reliability of the scanning paths are established using cumulative probability distribution functions for process output criteria such as sample density, thermal homogeneity, etc. A customized genetic algorithm is used along with the simulation model......Selective laser melting is yet to become a standardized industrial manufacturing technique. The process continues to suffer from defects such as distortions, residual stresses, localized deformations and warpage caused primarily due to the localized heating, rapid cooling and high temperature...... gradients that occur during the process. While process monitoring and control of selective laser melting is an active area of research, establishing the reliability and robustness of the process still remains a challenge.In this paper, a methodology for generating reliable, optimized scanning paths...

  12. Improving Completeness of Geometric Models from Terrestrial Laser Scanning Data

    Directory of Open Access Journals (Sweden)

    Clemens Nothegger

    2011-12-01

    Full Text Available The application of terrestrial laser scanning for the documentation of cultural heritage assets is becoming increasingly common. While the point cloud by itself is sufficient for satisfying many documentation needs, it is often desirable to use this data for applications other than documentation. For these purposes a triangulated model is usually required. The generation of topologically correct triangulated models from terrestrial laser scans, however, still requires much interactive editing. This is especially true when reconstructing models from medium range panoramic scanners and many scan positions. Because of residual errors in the instrument calibration and the limited spatial resolution due to the laser footprint, the point clouds from different scan positions never match perfectly. Under these circumstances many of the software packages commonly used for generating triangulated models produce models which have topological errors such as surface intersecting triangles, holes or triangles which violate the manifold property. We present an algorithm which significantly reduces the number of topological errors in the models from such data. The algorithm is a modification of the Poisson surface reconstruction algorithm. Poisson surfaces are resilient to noise in the data and the algorithm always produces a closed manifold surface. Our modified algorithm partitions the data into tiles and can thus be easily parallelized. Furthermore, it avoids introducing topological errors in occluded areas, albeit at the cost of producing models which are no longer guaranteed to be closed. The algorithm is applied to scan data of sculptures of the UNESCO World Heritage Site Schönbrunn Palace and data of a petrified oyster reef in Stetten, Austria. The results of the method’s application are discussed and compared with those of alternative methods.

  13. Categorisation of full waveform data provided by laser scanning devices

    Science.gov (United States)

    Ullrich, Andreas; Pfennigbauer, Martin

    2011-11-01

    In 2004, a laser scanner device for commercial airborne laser scanning applications, the RIEGL LMS-Q560, was introduced to the market, making use of a radical alternative approach to the traditional analogue signal detection and processing schemes found in LIDAR instruments so far: digitizing the echo signals received by the instrument for every laser pulse and analysing these echo signals off-line in a so-called full waveform analysis in order to retrieve almost all information contained in the echo signal using transparent algorithms adaptable to specific applications. In the field of laser scanning the somewhat unspecific term "full waveform data" has since been established. We attempt a categorisation of the different types of the full waveform data found in the market. We discuss the challenges in echo digitization and waveform analysis from an instrument designer's point of view and we will address the benefits to be gained by using this technique, especially with respect to the so-called multi-target capability of pulsed time-of-flight LIDAR instruments.

  14. Computer-Controlled 3D Laser Scanning Microscope Based On Optical Disk Technology.

    Science.gov (United States)

    Schweizer, P.; Neveux, L.; Chiaramello, M.; Monteil, P.; Ostrowsky, D. B...

    1987-08-01

    We describe RASCALS* (RAster SCAn Laser System) a 2D and 3D scanning laser microscope and outline it's performance. This system, based on optical disk technology and a PC compatible computer offers an interesting cost/performance ratio compared to existing laser scanning microscopes.

  15. Fluorescence imaging and spectroscopy of motile sperm cells and CHO cells in an optical trap (laser tweezers)

    Science.gov (United States)

    Koenig, Karsten; Liu, Yagang; Krasieva, Tatiana B.; Patrizio, Pasquale; Tadir, Yona; Sonek, Gregory J.; Berns, Michael W.; Tromberg, Bruce J.

    1995-05-01

    We describe fluorescence spectroscopy and imaging studies of optically trapped single Chinese hamster ovary (CHO) and motile human sperm cells. The NIR trapping beam was provided by a tunable, multimode continuous wave Ti:Sapphire laser. The beam was introduced into an inverted confocal laser scanning microscope. Fluorescence of cells in the single- beam gradient force optical trap was excited with a 488 nm microbeam (laser scanning microscopy) or with 365 nm radiation from a high- pressure mercury lamp. Modifications to NADH-attributed autofluorescence and Rhodamine- and Propidium Iodide-attributed xenofluorescence indicate a significant cell-damaging effect of 760 nm trapping beams. 760 nm effects produce a biological response comparable to UVA-induced oxidative stress and appear to be a consequence to two-photon absorption.

  16. Ta Keo Temple Reconstruction Based on Terrestrial Laser Scanning Technology

    Directory of Open Access Journals (Sweden)

    X. Xi

    2015-08-01

    Full Text Available Ta Keo temple is one of the very famous temple complex of Angkor Wat in northwestern Cambodia. It has been suffering massive collapse and other serious damages in recent years. Nowadays, Terrestrial Laser Scanning(TLS technology is considered as a wellestablished resource for heritage documentation and protection (Lerma et al, 2008; Reshetyuk, 2009. This paper used TLS to reconstruct Ta Keo Temple. Firstly, we acquired 71 scanning stations of points cloud data with high density and high accuracy, and over one thousand images with high spatial resolution about the temple. Secondly, the raw points cloud data were denoised, reduced and managed efficiently, and registrated using an adjusted ICP algorithm. Thirdly, a triangulation method was used to model most objects. At last, we mapped the texture data into the digital model and a 3-D model of Ta Keo with high accuracy was achieved. The authors focus on large object reconstruction by TLS technology, and pay much attention to the scanning design, multi-station data and the whole project’s data registration, and texture mapping and so on. The research result will be useful for Ta Keo restoration, reconstruction and protection. Also, it is a good reference source for large complex buildings reconstruction when using terrestrial laser scanning technology.

  17. Ta Keo Temple Reconstruction Based on Terrestrial Laser Scanning Technology

    Science.gov (United States)

    Xi, X.; Wang, C.; Wan, Y. P.; Khuon, K. N.

    2015-08-01

    Ta Keo temple is one of the very famous temple complex of Angkor Wat in northwestern Cambodia. It has been suffering massive collapse and other serious damages in recent years. Nowadays, Terrestrial Laser Scanning(TLS) technology is considered as a wellestablished resource for heritage documentation and protection (Lerma et al, 2008; Reshetyuk, 2009). This paper used TLS to reconstruct Ta Keo Temple. Firstly, we acquired 71 scanning stations of points cloud data with high density and high accuracy, and over one thousand images with high spatial resolution about the temple. Secondly, the raw points cloud data were denoised, reduced and managed efficiently, and registrated using an adjusted ICP algorithm. Thirdly, a triangulation method was used to model most objects. At last, we mapped the texture data into the digital model and a 3-D model of Ta Keo with high accuracy was achieved. The authors focus on large object reconstruction by TLS technology, and pay much attention to the scanning design, multi-station data and the whole project's data registration, and texture mapping and so on. The research result will be useful for Ta Keo restoration, reconstruction and protection. Also, it is a good reference source for large complex buildings reconstruction when using terrestrial laser scanning technology.

  18. Measurement Axis Searching Model for Terrestrial Laser Scans Registration

    Directory of Open Access Journals (Sweden)

    Shaoxing Hu

    2016-01-01

    Full Text Available Nowadays, terrestrial Lidar scans can cover rather a large area; the point densities are strongly varied because of the line-of-sight measurement principle in potential overlaps with scans taken from different viewpoints. Most of the traditional methods focus on registration algorithm and ignore searching model. Sometimes the traditional methods are directly used to align two point clouds; a large critically unsolved problem of the large biases will be created in areas distant from the overlaps while the local overlaps are often aligned well. So a novel measurement axis searching model (MASM has been proposed in this paper. The method includes four steps: (1 the principal axis fitting, (2 the measurement axis generation, (3 low-high-precision search, and (4 result generation. The principal axis gives an orientation to the point cloud; the search scope is limited by the measurement axis. The point cloud orientation can be adjusted gradually until the achievement of the global optimum using low- and high-precision search. We perform some experiments with simulated point clouds and real terrestrial laser scans. The results of simulated point clouds have shown the processing steps of our method, and the results of real terrestrial laser scans have shown the sensitivity of the approach with respect to the indoor and outdoor scenes.

  19. Laser induced fluorescence in a pulsed argon plasma

    International Nuclear Information System (INIS)

    Scime, Earl; Biloiu, Costel; Compton, Christopher; Doss, Forrest; Venture, Daniel; Heard, John; Choueiri, Edgar; Spektor, Rostislav

    2005-01-01

    A time-resolved laser induced fluorescence (LIF) technique for pulsed argon plasmas is described. A low power, tunable diode laser pumps a three level Ar II transition sequence at a wavelength of 668.6138 nm. With a standard LIF system designed for steady-state plasmas (e.g., 4 kHz optical chopper, 20 kHz band-width detector, and a lock-in amplifier), we demonstrate that the evolution of the ion velocity distribution can be resolved with a time resolution of 1 ms through a combination of time-series averaging and post-acquisition digital signal processing

  20. Changes in pupil size following panretinal retinal photocoagulation: conventional laser vs pattern scan laser (PASCAL).

    Science.gov (United States)

    Yilmaz, I; Perente, I; Saracoglu, B; Yazici, A T; Taskapili, M

    2016-10-01

    PurposeTo evaluate and compare the possible changes in pupil size subsequent to panretinal laser photocoagulation (PRP) via conventional laser and pattern scan laser (PASCAL).Patients and methodsForty eyes of 40 patients with diabetic retinopathy were included. 20 eyes had a PRP via conventional laser and formed Group 1. 20 eyes had a PRP via PASCAL laser and formed Group 2. The participants underwent standard ophthalmologic examination at baseline. Automated infrared pupillometry were performed at baseline and month 1.ResultsThe mean pupillary measurements (mm) for Group 1 (in the order photopic, mesopic, and scotopic conditions) were 2.88±0.34, 3.38±0.40, and 3.95±0.38, and changed to 3.64±0.42, 4.18±0.42, and 4.58±0.48, respectively. There was significant increase in pupil size at month 1 (PPASCAL laser.

  1. QUANTIFICATION OF BIOFILMS IN MULTI-SPECTRAL DIGITAL1 VOLUMES FROM CONFOCAL LASER-SCANNING MICROSCOPES

    Directory of Open Access Journals (Sweden)

    Karsten Rodenacker

    2011-05-01

    Full Text Available Populations of bacteria in sludge flocs and biofilm marked by fluorescence marked with fluorescent probes are digitised with a confocal laser scanning microscope. These data are used to analyse the microbial community structure, to obtain information on the localisation of specific bacterial groups and to examine gene expression. This information is urgently required for an in-depth understanding of the function and, more generally, the microbial ecology of biofilms. Methods derived from quantitative image analysis are applied to digitised data from confocal laser scanning microscopes to obtain quantitative descriptions of volumetric, topological (and topographical properties of different compartments of the components under research. In addition to free-moving flocs, also biofilms attached to a substratum in an experimental environment are analysed. Growth form as well as interaction of components are quantitatively described. Classical measurements of volume and intensity (shape, distribution and distance dependent interaction measurements using methods from mathematical morphology are performed. Mainly image (volume processing methods are outlined. Segmented volumes are globally and individually (in terms of 3Dconnected components measured and used for distance mapping transform as well as for estimation of geodesic distances from the substrate. All transformations are applied on the 3D data set. Resulting distance distributions are quantified and related to information on the identity and activity of the probe-identified bacteria.

  2. An Airborne Scanning Laser Altimetry Survey of Long Valley, California

    Science.gov (United States)

    Hofton, M. A.; Blair, J. B.; Minster, J.-B.; Ridgway, J. R.; Williams, N. P.; Bufton, J. L.; Rabine, D. L.

    1999-01-01

    Between 28 September and 7 October 1995, we conducted an airborne laser altimetry experiment over the Long Valley caldera, California, in which each of two scanning laser altimeters (dubbed SLICER and RASCAL) were flown in a NASA T-39 jet aircraft. Operating concurrently were a Global Positioning System (GPS) guidance system and dual frequency receivers for precise navigation and post-flight calculation or the airplane trajectory relative to a ground station, and an inertial navigation system (INS) for attitude determination. Reduction of raw laser ranges requires merging the differential kinematic GPS aircraft trajectory and the INS data with the laser data, and determination of the atmospheric delay. Data geolocation consists of obtaining the centre location and the mean elevation within each footprint in a geodetic coordinate system. The elevation of Crowley Lake is recovered to an accuracy of approximately 3 cm or better from 3 km above ground level and crossover analysis indicates that the elevation estimates are consistent from pass to pass. We test our geolocation procedures by comparing laser-derived elevations with those determined in situ for recognizable ground features. A comparison of laser and GPS-derived positions shows that the horizontal accuracy is better than the diameter of the footprint and vertical accuracy is within the error inherent in the range measurement. A comparison of SLICER elevation data with digital elevation models (DEMs) of the region shows that the DEM data provides surface topography to within stated accuracy limits. Although research continues to utilize the full potential of laser altimetry data, our results constitute a successful demonstration that the technique may be used to perform geodetic monitoring of surface topographic changes.

  3. Laser and sunlight-induced fluorescence from chlorophyll pigments

    Science.gov (United States)

    Kim, H. H.; Brown, K. S.

    1986-01-01

    Fluorescence properties of chlorophyll pigment bearing plant foliage utilizing a 337 nm nitrogen laser and integrating sphere were studied. Measured yields, in terms of number of photons emitted per 100 photons absorbed, range from 1.5 to 0.1 for the 685 nm peak, and from 4.2 to 0.2 for the 730 nm peak. Decreasing order of magnitude puts herbaceous leaves ahead of all others followed by broad leaves of hardwoods and coniferous needles. Meaningful quantization for the fluorescence peaks at 430 and 530 nm could not be attained. Passive monitoring of these fluorescence peaks is successful only for the 685 nm from the ocean surface. Field data show the reflectance changes at 685 nm due to the algae presence amounts to 1% at most.

  4. Direct probing of chromatography columns by laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    McGuffin, V.L.

    1992-12-07

    This report summarizes the progress and accomplishments of this research project from September 1, 1989 to February 28, 1993. During this period, we have accomplished all of the primary scientific objectives of the research proposal: (1) constructed and evaluated a laser-induced fluorescence detection system that allows direct examination of the chromatographic column, (2) examined nonequilibrium processes that occur upon solute injection and elution, (3) examined solute retention in liquid chromatography as a function of temperature and pressure, (4) examined solute zone dispersion in liquid chromatography as a function of temperature and pressure, and (5) developed appropriate theoretical models to describe these phenomena. In each of these studies, substantial knowledge has been gained of the fundamental processes that are responsible for chromatographic separations. In addition to these primary research objectives, we have made significant progress in three related areas: (1) examined pyrene as a fluorescent polarity probe insupercritical fluids and liquids as a function of temperature and pressure, (2) developed methods for the class-selective identification of polynuclear aromatic hydrocarbons in coal-derived fluids by microcolumn liquid chromatography with fluorescence quenching detection, and (3) developed methods for the determination of saturated and unsaturated (including omega-3) fatty acids in fish oil extracts by microcolumn liquid chromatography with laser-induced fluorescence detection. In these studies, the advanced separation and detection techniques developed in our laboratory are applied to practical problems of environmental and biomedical significance.

  5. Detection of vegetation stress from laser-induced fluorescence signatures

    International Nuclear Information System (INIS)

    Subhash, N.

    1995-01-01

    The in vivo laser-induced fluorescence (LIF) signatures of UV irradiated Salvia splendens plants were measured using an Optical Multichannel Analyser (OMA) system with Nitrogen laser excitation. The LIF spectra which consisted of the blue-green and the red chlorophyll bands were analysed with a non-linear interactive procedure using Gaussian spectral functions. The fluorescence intensity ratios of the various bands obtained from curve fitted parameters were found to be more sensitive to changes in the photosynthetic activity of the plant. The variation in the intensity ratio for the chlorophyll bands for nutrient stressed sunflower, cotton and groundnut plants as well as the nutrient and water stressed rice plants are also presented. It is observed that vegetation stress not only changes the fluorescence intensity ratios and the vitality index of the plant but also changes the peak position of the emission bands, in some cases. It is also seen that analysis of the fluorescence spectra in vegetation remote sensing applications would require a deconvolution procedure to evaluate the exact contribution of each band in the total spectra. (author). 23 refs, 8 figs, 5 tabs

  6. Kr II laser-induced fluorescence for measuring plasma acceleration.

    Science.gov (United States)

    Hargus, W A; Azarnia, G M; Nakles, M R

    2012-10-01

    We present the application of laser-induced fluorescence of singly ionized krypton as a diagnostic technique for quantifying the electrostatic acceleration within the discharge of a laboratory cross-field plasma accelerator also known as a Hall effect thruster, which has heritage as spacecraft propulsion. The 728.98 nm Kr II transition from the metastable 5d(4)D(7/2) to the 5p(4)P(5/2)(∘) state was used for the measurement of laser-induced fluorescence within the plasma discharge. From these measurements, it is possible to measure velocity as krypton ions are accelerated from near rest to approximately 21 km/s (190 eV). Ion temperature and the ion velocity distributions may also be extracted from the fluorescence data since available hyperfine splitting data allow for the Kr II 5d(4)D(7/2)-5p(4)P(5/2)(∘) transition lineshape to be modeled. From the analysis, the fluorescence lineshape appears to be a reasonable estimate for the relatively broad ion velocity distributions. However, due to an apparent overlap of the ion creation and acceleration regions within the discharge, the distributed velocity distributions increase ion temperature determination uncertainty significantly. Using the most probable ion velocity as a representative, or characteristic, measure of the ion acceleration, overall propellant energy deposition, and effective electric fields may be calculated. With this diagnostic technique, it is possible to nonintrusively characterize the ion acceleration both within the discharge and in the plume.

  7. Terrestrial laser scanning in monitoring of anthropogenic objects

    Directory of Open Access Journals (Sweden)

    Zaczek-Peplinska Janina

    2017-12-01

    Full Text Available The registered xyz coordinates in the form of a point cloud captured by terrestrial laser scanner and the intensity values (I assigned to them make it possible to perform geometric and spectral analyses. Comparison of point clouds registered in different time periods requires conversion of the data to a common coordinate system and proper data selection is necessary. Factors like point distribution dependant on the distance between the scanner and the surveyed surface, angle of incidence, tasked scan’s density and intensity value have to be taken into consideration. A prerequisite for running a correct analysis of the obtained point clouds registered during periodic measurements using a laser scanner is the ability to determine the quality and accuracy of the analysed data. The article presents a concept of spectral data adjustment based on geometric analysis of a surface as well as examples of geometric analyses integrating geometric and physical data in one cloud of points: cloud point coordinates, recorded intensity values, and thermal images of an object. The experiments described here show multiple possibilities of usage of terrestrial laser scanning data and display the necessity of using multi-aspect and multi-source analyses in anthropogenic object monitoring. The article presents examples of multisource data analyses with regard to Intensity value correction due to the beam’s incidence angle. The measurements were performed using a Leica Nova MS50 scanning total station, Z+F Imager 5010 scanner and the integrated Z+F T-Cam thermal camera.

  8. Application of Laser Scanning for Creating Geological Documentation

    Science.gov (United States)

    Buczek, Michał; Paszek, Martyna; Szafarczyk, Anna

    2018-03-01

    A geological documentation is based on the analyses obtained from boreholes, geological exposures, and geophysical methods. It consists of text and graphic documents, containing drilling sections, vertical crosssections through the deposit and various types of maps. The surveying methods (such as LIDAR) can be applied in measurements of exposed rock layers, presented in appendices to the geological documentation. The laser scanning allows obtaining a complete profile of exposed surfaces in a short time and with a millimeter accuracy. The possibility of verifying the existing geological cross-section with laser scanning was tested on the example of the AGH experimental mine. The test field is built of different lithological rocks. Scans were taken from a single station, under favorable measuring conditions. The analysis of the signal intensity allowed to divide point cloud into separate geological layers. The results were compared with the geological profiles of the measured object. The same approach was applied to the data from the Vietnamese hard coal open pit mine Coc Sau. The thickness of exposed coal bed deposits and gangue layers were determined from the obtained data (point cloud) in combination with the photographs. The results were compared with the geological cross-section.

  9. Application of Laser Scanning for Creating Geological Documentation

    Directory of Open Access Journals (Sweden)

    Buczek Michał

    2018-01-01

    Full Text Available A geological documentation is based on the analyses obtained from boreholes, geological exposures, and geophysical methods. It consists of text and graphic documents, containing drilling sections, vertical crosssections through the deposit and various types of maps. The surveying methods (such as LIDAR can be applied in measurements of exposed rock layers, presented in appendices to the geological documentation. The laser scanning allows obtaining a complete profile of exposed surfaces in a short time and with a millimeter accuracy. The possibility of verifying the existing geological cross-section with laser scanning was tested on the example of the AGH experimental mine. The test field is built of different lithological rocks. Scans were taken from a single station, under favorable measuring conditions. The analysis of the signal intensity allowed to divide point cloud into separate geological layers. The results were compared with the geological profiles of the measured object. The same approach was applied to the data from the Vietnamese hard coal open pit mine Coc Sau. The thickness of exposed coal bed deposits and gangue layers were determined from the obtained data (point cloud in combination with the photographs. The results were compared with the geological cross-section.

  10. SEMI - AUTOMATED BUILDING E XTRACTION FROM AIRBORNE LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    Marjasiewicz Marcin

    2014-12-01

    Full Text Available The main idea of this project is to introduce a conception of semi - automated method for building model extraction from Airborne Laser Scanning data. The presented method is based on the RANSAC algorithm, which provides automatic collection planes for roofs model creation. In the case of Airborne Laser Scanning, the algorithm can process point clouds influenced with noise and erroneous measurement (gross errors. The RANSAC algorithm is based on the iterative processing of a set of points in order to estimate the geometric model. Research of u sing algorithm for ALS data was performed in available Cloud Compare and SketchUP software. An important aspect in this research was algorithm parameters selection, which was made on the basis of characteristics of point cloud and scanned objects. Analysis showed that the accuracy of plane extraction with RANSAC algorithm does not exceed 20 centimeters for point clouds of density 4 pts . /m 2 . RANSAC can be successfully used in buildings modelling based on ALS data. Roofs created by the presented method could be used in visualizations on a much better level than Level of Detail 2 by CityGML standard. If model is textured it can represent LoD3 standard.

  11. Quantitative laser-induced fluorescence measurements of nitric oxide in a heavy-duty Diesel engine

    NARCIS (Netherlands)

    Verbiezen, K.; Klein-Douwel, R. J. H.; van Viet, A. P.; Donkerbroek, A. J.; Meerts, W. L.; Dam, N. J.; ter Meulen, J. J.

    2007-01-01

    We present quantitative, in-cylinder, UV-laser-induced fluorescence measurements of nitric oxide in a heavy-duty Diesel engine. Processing of the raw fluorescence signals includes a detailed correction, based on additional measurements, for the effect of laser beam and fluorescence attenuation, and

  12. Dielectric and fluorescent samples imaged by scanning near-field optical microscopy in reflection

    OpenAIRE

    Jalocha, A.; Jalocha, A.; van Hulst, N.F.

    1995-01-01

    Dielectric fluorescent samples are imaged by scanning near- field optical microscopy in reflection. A non-metallized tapered fibre tip is used both as an emitter and a detector. Shear force feedback controls the distance between the tip and the sample and gives simultaneously a topographic image of the surface. A direct correlation with the optical image is obtained. We demonstrate that this reflection setup is suitable for dielectric samples. Images in fluorescence have been obtained o­n Lan...

  13. Scanning laser beam displays based on a 2D MEMS

    Science.gov (United States)

    Niesten, Maarten; Masood, Taha; Miller, Josh; Tauscher, Jason

    2010-05-01

    The combination of laser light sources and MEMS technology enables a range of display systems such as ultra small projectors for mobile devices, head-up displays for vehicles, wearable near-eye displays and projection systems for 3D imaging. Images are created by scanning red, green and blue lasers horizontally and vertically with a single two-dimensional MEMS. Due to the excellent beam quality of laser beams, the optical designs are efficient and compact. In addition, the laser illumination enables saturated display colors that are desirable for augmented reality applications where a virtual image is used. With this technology, the smallest projector engine for high volume manufacturing to date has been developed. This projector module has a height of 7 mm and a volume of 5 cc. The resolution of this projector is WVGA. No additional projection optics is required, resulting in an infinite focus depth. Unlike with micro-display projection displays, an increase in resolution will not lead to an increase in size or a decrease in efficiency. Therefore future projectors can be developed that combine a higher resolution in an even smaller and thinner form factor with increased efficiencies that will lead to lower power consumption.

  14. Scanning laser 'en face' retinal imaging of epiretinal membranes.

    Science.gov (United States)

    Reznicek, Lukas; Dabov, Simeon; Kayat, Bader; Liegl, Raffael; Kampik, Anselm; Ulbig, Michael; Kernt, Marcus

    2014-04-01

    Comparison of scanning laser ophthalmoscopy (SLO) based 'en face' imaging techniques of patients with epiretinal membranes (ERM) and evaluation of the accuracy of preoperative diagnostic imaging. A consecutive, prospective series of 53 study eyes of 46 patients with clinically diagnosed and in optical coherence tomography (OCT) confirmed symptomatic ERMs were included in this study. Spectral domain (SD-) OCT volume scans (20° × 20° with 49 horizontal sections, ART 15) including SLO en face and fundus autofluorescence (FAF) images of the macula were obtained with HRA2 (Heidelberg Retina Angiograph-Optical Coherence Tomography, Heidelberg Engineering, Heidelberg, Germany). In addition, wide-field SLO color and FAF images (Optomap 200Tx, Optos PLC, Dunfermline, UK) were performed also covering the macular area. En face images of both devices were graded for each included study eye based on SD-OCT cross sectional scans. Grading of SD-OCT (HRA2) based SLO en face green-blue enhanced multi-color, green reflectance, blue reflectance and standard multi-color visualization revealed a better detectability of ERM than SD-OCT-based en face infrared or FAF images or wide-field SLO (Optomap) based pseudo-color, red laser separation, green laser separation, or FAF images. Both FAF visualizations, HRA2 and Optomap based, achieved low mean scores. SD-OCT based en face thickness map visualization revealed good visualization but poor demarcation of epiretinal membranes. In summary, en face regular or enhanced multicolor SLO images acquired with HRA2 allow a better visualization of epiretinal membranes for preoperative evaluation compared to SD-OCT based en face thickness map or pseudo-color images acquired with Optomap while infrared or FAF images are least suitable to depict epiretinal membranes.

  15. Time-resolved laser fluorescence spectroscopy of organic ligands by europium: Fluorescence quenching and lifetime properties

    Science.gov (United States)

    Nouhi, A.; Hajjoul, H.; Redon, R.; Gagné, J. P.; Mounier, S.

    2018-03-01

    Time-resolved Laser Fluorescence Spectroscopy (TRLFS) has proved its usefulness in the fields of biophysics, life science and geochemistry to characterize the fluorescence probe molecule with its chemical environment. The purpose of this study is to demonstrate the applicability of this powerful technique combined with Steady-State (S-S) measurements. A multi-mode factor analysis, in particular CP/PARAFAC, was used to analyze the interaction between Europium (Eu) and Humic substances (HSs) extracted from Saint Lawrence Estuary in Canada. The Saint Lawrence system is a semi-enclosed water stream with connections to the Atlantic Ocean and is an excellent natural laboratory. CP/PARAFAC applied to fluorescence S-S data allows introspecting ligands-metal interactions and the one-site 1:1 modeling gives information about the stability constants. From the spectral signatures and decay lifetimes data given by TRLFS, one can deduce the fluorescence quenching which modifies the fluorescence and discuss its mechanisms. Results indicated a relatively strong binding ability between europium and humic substances samples (Log K value varies from 3.38 to 5.08 at pH 7.00). Using the Stern-Volmer plot, it has been concluded that static and dynamic quenching takes places in the case of salicylic acid and europium interaction while for HSs interaction only a static quenching is observed.

  16. Laser-induced fluorescence detection strategies for sodium atoms and compounds in high-pressure combustors

    Science.gov (United States)

    Weiland, Karen J. R.; Wise, Michael L.; Smith, Gregory P.

    1993-01-01

    A variety of laser-induced fluorescence schemes were examined experimentally in atmospheric pressure flames to determine their use for sodium atom and salt detection in high-pressure, optically thick environments. Collisional energy transfer plays a large role in fluorescence detection. Optimum sensitivity, at the parts in 10 exp 9 level for a single laser pulse, was obtained with the excitation of the 4p-3s transition at 330 nm and the detection of the 3d-3p fluorescence at 818 nm. Fluorescence loss processes, such as ionization and amplified spontaneous emission, were examined. A new laser-induced atomization/laser-induced fluorescence detection technique was demonstrated for NaOH and NaCl. A 248-nm excimer laser photodissociates the salt molecules present in the seeded flames prior to atom detection by laser-induced fluorescence.

  17. Automatic Indoor Building Reconstruction from Mobile Laser Scanning Data

    Science.gov (United States)

    Xie, L.; Wang, R.

    2017-09-01

    Indoor reconstruction from point clouds is a hot topic in photogrammetry, computer vision and computer graphics. Reconstructing indoor scene from point clouds is challenging due to complex room floorplan and line-of-sight occlusions. Most of existing methods deal with stationary terrestrial laser scanning point clouds or RGB-D point clouds. In this paper, we propose an automatic method for reconstructing indoor 3D building models from mobile laser scanning point clouds. The method includes 2D floorplan generation, 3D building modeling, door detection and room segmentation. The main idea behind our approach is to separate wall structure into two different types as the inner wall and the outer wall based on the observation of point distribution. Then we utilize a graph cut based optimization method to solve the labeling problem and generate the 2D floorplan based on the optimization result. Subsequently, we leverage an ?-shape based method to detect the doors on the 2D projected point clouds and utilize the floorplan to segment the individual room. The experiments show that this door detection method can achieve a recognition rate at 97% and the room segmentation method can attain the correct segmentation results. We also evaluate the reconstruction accuracy on the synthetic data, which indicates the accuracy of our method is comparable to the state-of-the art.

  18. Adaptive optics scanning laser ophthalmoscope imaging: technology update

    Directory of Open Access Journals (Sweden)

    Merino D

    2016-04-01

    Full Text Available David Merino, Pablo Loza-Alvarez The Institute of Photonic Sciences (ICFO, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, Spain Abstract: Adaptive optics (AO retinal imaging has become very popular in the past few years, especially within the ophthalmic research community. Several different retinal techniques, such as fundus imaging cameras or optical coherence tomography systems, have been coupled with AO in order to produce impressive images showing individual cell mosaics over different layers of the in vivo human retina. The combination of AO with scanning laser ophthalmoscopy has been extensively used to generate impressive images of the human retina with unprecedented resolution, showing individual photoreceptor cells, retinal pigment epithelium cells, as well as microscopic capillary vessels, or the nerve fiber layer. Over the past few years, the technique has evolved to develop several different applications not only in the clinic but also in different animal models, thanks to technological developments in the field. These developments have specific applications to different fields of investigation, which are not limited to the study of retinal diseases but also to the understanding of the retinal function and vision science. This review is an attempt to summarize these developments in an understandable and brief manner in order to guide the reader into the possibilities that AO scanning laser ophthalmoscopy offers, as well as its limitations, which should be taken into account when planning on using it. Keywords: high-resolution, in vivo retinal imaging, AOSLO

  19. Extraction of power lines from mobile laser scanning data

    Science.gov (United States)

    Xiang, Qing; Li, Jonathan; Wen, Chenglu; Huang, Pengdi

    2016-03-01

    Modern urban life is becoming increasingly more dependent on reliable electric power supply. Since power outages cause substantial financial losses to producers, distributors and consumers of electric power, it is in the common interest to minimize failures of power lines. In order to detect defects as early as possible and to plan efficiently the maintenance activities, distribution networks are regularly inspected. Carrying out foot patrols or climbing the structures to visually inspect transmission lines and aerial surveys (e.g., digital imaging or most recent airborne laser scanning (ALS) are the two most commonly used methods of power line inspection. Although much faster in comparison to the foot patrol inspection, aerial inspection is more expensive and usually less accurate, in complex urban areas particularly. This paper presents a scientific work that is done in the use of mobile laser scanning (MLS) point clouds for automated extraction of power lines. In the proposed method, 2D power lines are extracted using Hough transform in the projected XOY plane and the 3D power line points are visualized after the point searching. Filtering based on an elevation threshold is applied, which is combined with the vehicle's trajectory in the horizontal section.

  20. Determination of foveal location using scanning laser polarimetry.

    Science.gov (United States)

    VanNasdale, Dean A; Elsner, Ann E; Weber, Anke; Miura, Masahiro; Haggerty, Bryan P

    2009-03-25

    The fovea is the retinal location responsible for our most acute vision. There are several methods used to localize the fovea, but the fovea is not always easily identifiable. Landmarks used to determine the foveal location are variable in normal subjects and localization becomes even more difficult in instances of retinal disease. In normal subjects, the photoreceptor axons that make up the Henle fiber layer are cylindrical and the radial orientation of these fibers is centered on the fovea. The Henle fiber layer exhibits form birefringence, which predictably changes polarized light in scanning laser polarimetry imaging. In this study 3 graders were able to repeatably identify the fovea in 35 normal subjects using near infrared image types with differing polarization content. There was little intra-grader, inter-grader, and inter-image variability in the graded foveal position for 5 of the 6 image types examined, with accuracy sufficient for clinical purposes. This study demonstrates that scanning laser polarimetry imaging can localize the fovea by using structural properties inherent in the central macula.

  1. Time efficient methods for scanning a fluorescent membrane with a fluorescent microscopic imager for the quality assurance of food

    Science.gov (United States)

    Lerm, Steffen; Holder, Silvio; Schellhorn, Mathias; Brückner, Peter; Linß, Gerhard

    2013-05-01

    An important part of the quality assurance of meat is the estimation of germs in the meat exudes. The kind and the number of the germs in the meat affect the medical risk for the consumer of the meat. State-of-the-art analyses of meat are incubator test procedures. The main disadvantages of such incubator tests are the time consumption, the necessary equipment and the need of special skilled employees. These facts cause in high inspection cost. For this reason a new method for the quality assurance is necessary which combines low detection limits and less time consumption. One approach for such a new method is fluorescence microscopic imaging. The germs in the meat exude are caught in special membranes by body-antibody reactions. The germ typical signature could be enhanced with fluorescent chemical markers instead of reproduction of the germs. Each fluorescent marker connects with a free germ or run off the membrane. An image processing system is used to detect the number of fluorescent particles. Each fluorescent spot should be a marker which is connected with a germ. Caused by the small object sizes of germs, the image processing system needs a high optical magnification of the camera. However, this leads to a small field of view and a small depth of focus. For this reasons the whole area of the membrane has to be scanned in three dimensions. To minimize the time consumption, the optimal path has to be found. This optimization problem is influenced by features of the hardware and is presented in this paper. The traversing range in each direction, the step width, the velocity, the shape of the inspection volume and the field of view have influence on the optimal path to scan the membrane.

  2. Assembly of positioner of automated two-dimensional scan coupled to X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Silva, Leonardo Santiago Melgaço

    2011-01-01

    This work describes the design and assembling of a prototype automated positioner two-dimensional scanning coupled to X-ray fluorescence spectrometry. The work aims to achieve a portable and easy to use, device of broad utility in the analysis of samples by X-ray fluorescence area of expertise and research. The two-dimensional scanning of the positioner is by means of two stepper motors controlled by a microcontroller PIC 16F877A, encoder and optical sensors. The user interacts with the XY table through an interface program for the Windows operating system, which communicates with the microcontroller through the serial port. The system of Fluorescence Spectroscopy incorporated into the positioner consists of a system commercially available system from the company AMPTEK, where the primary source of excitation of the sample was a source of 241 Am of 59.5 KeV emissions. Resolution and accuracy of tests were performed in the XY scanning process and reproducibility of the same kit with the fluorescence spectrometry X-ray. Qualitative tests by X-ray fluorescence spectrometry in samples were performed to demonstrate the applicability and versatility of the project. It follows that the prototype illustrates a possible adequately to portable device for X-ray spectrometry of two-dimensional. (author)

  3. Poly(diacetylene) Monolayers Studied with a Fluorescence Scanning Near-Field Optical Microscope

    NARCIS (Netherlands)

    Moers, Marco H.P.; Moers, M.H.P.; Gaub, Hermann E.; van Hulst, N.F.

    1994-01-01

    A novel and powerful method to study the optical properties of thin lipid films which a resolution superior to confocal microscopy is presented. With a scanning near-field optical microscope, fluorescence images of a Langmuir-Blodgett film of diethylene glycol diamine pentacosadiynoic amide are

  4. Dielectric and fluorescent samples imaged by scanning near-field optical microscopy in reflection

    NARCIS (Netherlands)

    Jalocha, A.; Jalocha, A.; van Hulst, N.F.

    1995-01-01

    Dielectric fluorescent samples are imaged by scanning near- field optical microscopy in reflection. A non-metallized tapered fibre tip is used both as an emitter and a detector. Shear force feedback controls the distance between the tip and the sample and gives simultaneously a topographic image of

  5. Pavement cracking measurements using 3D laser-scan images

    International Nuclear Information System (INIS)

    Ouyang, W; Xu, B

    2013-01-01

    Pavement condition surveying is vital for pavement maintenance programs that ensure ride quality and traffic safety. This paper first introduces an automated pavement inspection system which uses a three-dimensional (3D) camera and a structured laser light to acquire dense transverse profiles of a pavement lane surface when it carries a moving vehicle. After the calibration, the 3D system can yield a depth resolution of 0.5 mm and a transverse resolution of 1.56 mm pixel −1 at 1.4 m camera height from the ground. The scanning rate of the camera can be set to its maximum at 5000 lines s −1 , allowing the density of scanned profiles to vary with the vehicle's speed. The paper then illustrates the algorithms that utilize 3D information to detect pavement distress, such as transverse, longitudinal and alligator cracking, and presents the field tests on the system's repeatability when scanning a sample pavement in multiple runs at the same vehicle speed, at different vehicle speeds and under different weather conditions. The results show that this dedicated 3D system can capture accurate pavement images that detail surface distress, and obtain consistent crack measurements in repeated tests and under different driving and lighting conditions. (paper)

  6. Two-Dimensional Fluorescence Spectroscopy for Measuring Uranium Isotopes in Femtosecond Laser Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Mark C.; Brumfield, Brian E.; Harilal, Sivanandan S.; Hartig, Kyle C.; Jovanovic, Igor

    2017-05-30

    We present the first two-dimensional fluorescence spectroscopy measurements of uranium isotopes in femtosecond laser ablation plasmas. A new method of signal normalization is presented to reduce noise in absorption-based measurements of laser ablation.

  7. Three-dimensional imaging of intracochlear tissue by scanning laser optical tomography (SLOT)

    Science.gov (United States)

    Tinne, N.; Nolte, L.; Antonopoulos, G. C.; Schulze, J.; Andrade, J.; Heisterkamp, A.; Meyer, H.; Warnecke, A.; Majdani, O.; Ripken, T.

    2016-02-01

    The presented study focuses on the application of scanning laser optical tomography (SLOT) for non-destructive visualization of anatomical structures inside the human cochlea ex vivo. SLOT is a laser-based highly efficient microscopy technique, which allows for tomographic imaging of the internal structure of transparent large-scale specimens (up to 1 cm3). Thus, in the field of otology this technique is best convenient for an ex vivo study of the inner ear anatomy. For this purpose, the preparation before imaging comprises mechanically assisted decalcification, dehydration as well as optical clearing of the cochlea samples. Here, we demonstrate results of SLOT visualizing hard and soft tissue structures of the human cochlea with an optical resolution in the micrometer range using absorption and autofluorescence as contrast mechanisms. Furthermore, we compare our results with the method of X-ray micro tomography (micro-CT, μCT) as clinical gold standard which is based only on absorption. In general, SLOT can provide the advantage of covering all contrast mechanisms known from other light microscopy techniques, such as fluorescence or scattering. For this reason, a protocol for antibody staining has been developed, which additionally enables selective mapping of cellular structures within the cochlea. Thus, we present results of SLOT imaging rodent cochleae showing specific anatomical structures such as hair cells and neurofilament via fluorescence. In conclusion, the presented study has shown that SLOT is an ideally suited tool in the field of otology for in toto visualization of the inner ear microstructure.

  8. Research on calibration algorithm in laser scanning projection system

    Science.gov (United States)

    Li, Li Juan; Qu, Song; Hou, Mao Sheng

    2017-10-01

    Laser scanning projection technology can project the image defined by the existing CAD digital model to the working surface, in the form of a laser harness profile. This projection is in accordance with the ratio of 1: 1. Through the laser harness contours with high positioning quality, the technical staff can carry out the operation with high precision. In a typical process of the projection, in order to determine the relative positional relationship between the laser projection instrument and the target, it is necessary to place several fixed reference points on the projection target and perform the calibration of projection. This position relationship is the transformation from projection coordinate system to the global coordinate system. The entire projection work is divided into two steps: the first step, the calculation of the projector six position parameters is performed, that is, the projector calibration. In the second step, the deflection angle is calculated by the known projector position parameter and the known coordinate points, and then the actual model is projected. Typically, the calibration requires the establishment of six reference points to reduce the possibility of divergence of the nonlinear equations, but the whole solution is very complex and the solution may still diverge. In this paper, the distance is detected combined with the calculation so that the position parameters of the projector can be solved by using the coordinate values of three reference points and the distance of at least one reference point to the projector. The addition of the distance measurement increases the stability of the solution of the nonlinear system and avoids the problem of divergence of the solution caused by the reference point which is directly under the projector. Through the actual analysis and calculation, the Taylor expansion method combined with the least squares method is used to obtain the solution of the system. Finally, the simulation experiment is

  9. Laser beam alignment and profilometry using diagnostic fluorescent safety mirrors

    Science.gov (United States)

    Lizotte, Todd E.

    2011-03-01

    There are a wide range of laser beam delivery systems in use for various purposes; including industrial and medical applications. Virtually all such beam delivery systems for practical purposes employ optical systems comprised of mirrors and lenses to shape, focus and guide the laser beam down to the material being processed. The goal of the laser beam delivery is to set the optimum parameters and to "fold" the beam path to reduce the mechanical length of the optical system, thereby allowing a physically compact system. In many cases, even a compact system can incorporate upwards of six mirrors and a comparable number of lenses all needing alignment so they are collinear. One of the major requirements for use of such systems in industry is a method of safe alignment. The alignment process requires that the aligner determine where the beam strikes each element. The aligner should also preferably be able to determine the shape or pattern of the laser beam at that point and its relative power. These alignments are further compounded in that the laser beams generated are not visible to the unaided human eye. Such beams are also often of relatively high power levels, and are thereby a significant hazard to the eyes of the aligner. Obvious an invisible beam makes it nearly impossible to align laser system without some form of optical assistance. The predominant method of visually aligning the laser beam delivery is the use of thermal paper, paper cards or fluorescing card material. The use of paper products which have limited power handling capability or coated plastics can produce significant debris and contaminants within the beam line that ultimately damage the optics. The use of the cards can also create significant laser light scatter jeopardizing the safety of the person aligning the system. This paper covers a new safety mirror design for use with at various UV and Near IR wavelengths (193 nm to 1064 nm) within laser beam delivery systems and how its use can

  10. Confocal laser scanning microscopy to estimate nanoparticles’ human skin penetration in vitro

    Directory of Open Access Journals (Sweden)

    Zou Y

    2017-10-01

    Full Text Available Ying Zou,1,2,* Anna Celli,2,3,* Hanjiang Zhu,2,* Akram Elmahdy,2 Yachao Cao,2 Xiaoying Hui,2 Howard Maibach2 1Skin & Cosmetic Research Department, Shanghai Skin Disease Hospital, Shanghai, People’s Republic of China; 2Department of Dermatology, School of Medicine, University of California San Francisco, San Francisco, CA, USA; 3San Francisco Veterans Medical Center, San Francisco, CA, USA *These authors contributed equally to this work Objective: With rapid development of nanotechnology, there is increasing interest in nanoparticle (NP application and its safety and efficacy on human skin. In this study, we utilized confocal laser scanning microscopy to estimate NP skin penetration.Methods: Three different-sized polystyrene NPs marked with red fluorescence were applied to human skin, and Calcium Green 5N was used as a counterstain. Dimethyl sulfoxide (DMSO and ethanol were used as alternative vehicles for NPs. Tape stripping was utilized as a barrier-damaged skin model. Skin biopsies dosed with NPs were incubated at 4°C or 37°C for 24 hours and imaged using confocal laser scanning microscopy.Results: NPs were localized in the stratum corneum (SC and hair follicles without penetrating the epidermis/dermis. Barrier alteration with tape stripping and change in incubation temperature did not induce deeper penetration. DMSO enhanced NP SC penetration but ethanol did not.Conclusion: Except with DMSO vehicle, these hydrolyzed polystyrene NPs did not penetrate intact or barrier-damaged human “viable” epidermis. For further clinical relevance, in vivo human skin studies and more sensitive analytic chemical methodology are suggested. Keywords: nanoparticles, skin penetration, stratum corneum, confocal laser scanning microscopy, tape stripping

  11. Imaging Single ZnO Vertical Nanowire Laser Cavities using UV-Laser Scanning Confocal Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gargas, D.J.; Toimil-Molares, M.E.; Yang, P.

    2008-11-17

    We report the fabrication and optical characterization of individual ZnO vertical nanowire laser cavities. Dilute nanowire arrays with interwire spacing>10 ?m were produced by a modified chemical vapor transport (CVT) method yielding an ideal platform for single nanowire imaging and spectroscopy. Lasing characteristics of a single vertical nanowire are presented, as well as high-resolution photoluminescence imaging by UV-laser scanning confocal microscopy. In addition, three-dimensional (3D) mapping of the photoluminescence emission performed in both planar and vertical dimensions demonstrates height-selective imaging useful for vertical nanowires and heteronanostructures emerging in the field of optoelectronics and nanophotonics.

  12. Detecting protein complexes in living cells from laser scanning confocal image sequences by the cross correlation raster image spectroscopy method.

    Science.gov (United States)

    Digman, Michelle A; Wiseman, Paul W; Horwitz, Alan R; Gratton, Enrico

    2009-01-01

    We describe a general method for detecting molecular complexes based on the analysis of single molecule fluorescence fluctuations from laser scanning confocal images. The method detects and quantifies complexes of two different fluorescent proteins noninvasively in living cells. Because in a raster scanned image successive pixels are measured at different times, the spatial correlation of the image contains information about dynamic processes occurring over a large time range, from the microseconds to seconds. The correlation of intensity fluctuations measured simultaneously in two channels detects protein complexes that carry two molecules of different colors. This information is obtained from the entire image. A map of the spatial distribution of protein complexes in the cell and their diffusion and/or binding properties can be constructed. Using this cross correlation raster image spectroscopy method, specific locations in the cell can be visualized where dynamics of binding and unbinding of fluorescent protein complexes occur. This fluctuation imaging method can be applied to commercial laser scanning microscopes thereby making it accessible to a large community of scientists.

  13. Forest structure analysis combining laser scanning with digital airborne photogrammetry

    Science.gov (United States)

    Lissak, Candide; Onda, Yuichi; Kato, Hiroaki

    2017-04-01

    The interest of Light Detection and Ranging (LiDAR) for vegetation structure analysis has been demonstrated in several research context. Indeed, airborne or ground Lidar surveys can provide detailed three-dimensional data of the forest structure from understorey forest to the canopy. To characterize at different timescale the vegetation components in dense cedar forests we can combine several sources point clouds from Lidar survey and photogrammetry data. For our study, Terrestrial Laser Scanning (TLS-Leica ScanStation C10 processed with Cyclone software) have been lead in three forest areas (≈ 200m2 each zone) mainly composed of japanese cedar (Japonica cryptomeria), in the region of Fukushima (Japan). The study areas are characterized by various vegetation densities. For the 3 areas, Terrestrial laser scanning has been performed from several location points and several heights. Various floors shootings (ground, 4m, 6m and 18m high) were able with the use of a several meters high tower implanted to study the canopy evolution following the Fukushima Daiishi nuclear power plant accident. The combination of all scanners provides a very dense 3D point cloud of ground and canopy structure (average 300 000 000 points). For the Tochigi forest area, a first test of a low-cost Unmanned Aerial Vehicle (UAV) photogrammetry has been lead and calibrated by ground GPS measurements to determine the coordinates of points. TLS combined to UAV photogrammetry make it possible to obtain information on vertical and horizontal structure of the Tochigi forest. This combination of technologies will allow the forest structure mapping, morphometry analysis and the assessment of biomass volume evolution from multi-temporal point clouds. In our research, we used a low-cost UAV 3 Advanced (200 m2 cover, 1300 pictures...). Data processing were performed using PotoScan Pro software to obtain a very dense point clouds to combine to TLS data set. This low-cost UAV photogrammetry data has been

  14. System Design Considerations In Bar-Code Laser Scanning

    Science.gov (United States)

    Barkan, Eric; Swartz, Jerome

    1984-08-01

    The unified transfer function approach to the design of laser barcode scanner signal acquisition hardware is considered. The treatment of seemingly disparate system areas such as the optical train, the scanning spot, the electrical filter circuits, the effects of noise, and printing errors is presented using linear systems theory. Such important issues as determination of depth of modulation, filter specification, tolerancing of optical components, and optimi-zation of system performance in the presence of noise are discussed. The concept of effective spot size to allow for impact of optical system and analog processing circuitry upon depth of modulation is introduced. Considerations are limited primarily to Gaussian spot profiles, but also apply to more general cases. Attention is paid to realistic bar-code symbol models and to implications with respect to printing tolerances.

  15. Classification of Mobile Laser Scanning Point Clouds from Height Features

    Science.gov (United States)

    Zheng, M.; Lemmens, M.; van Oosterom, P.

    2017-09-01

    The demand for 3D maps of cities and road networks is steadily growing and mobile laser scanning (MLS) systems are often the preferred geo-data acquisition method for capturing such scenes. Because MLS systems are mounted on cars or vans they can acquire billions of points of road scenes within a few hours of survey. Manual processing of point clouds is labour intensive and thus time consuming and expensive. Hence, the need for rapid and automated methods for 3D mapping of dense point clouds is growing exponentially. The last five years the research on automated 3D mapping of MLS data has tremendously intensified. In this paper, we present our work on automated classification of MLS point clouds. In the present stage of the research we exploited three features - two height components and one reflectance value, and achieved an overall accuracy of 73 %, which is really encouraging for further refining our approach.

  16. Selective sampling and edge enhancement in bar code laser scanning

    Science.gov (United States)

    Shellhammer, Stephen J.; Goren, David P.; Pavlidis, Theo

    1996-03-01

    This paper describes the basic design principles for a new series of bar code scanners from Symbol Technologies. Traditional bar code scanners include an edge detector which has several innate limitations. We propose replacing this edge detector with a selective sampling circuit. While the superiority of decoding the analog signal has been demonstrated, its implementation is too costly because of the need for considerable additional memory. Selective sampling achieves most of the advantages of analog decoding at a cost comparable to that of conventional decoders. Instead of sampling the signal periodically, it is only sampled when a certain event (e.g. an edge) is detected. At each edge two data values are produced: the edge time and the sampled value, often referred to as the edge strength. This strength value gives a measure of the intensity of the edge. Using selective sampling the new scanners can read poorly printed and noisy bar codes that cannot be read by traditional scanners. Another innate limitation of bar code laser scanners is the density of bar code that can be read. This limitation is due to the blurring of the bar code when scanned by a laser beam with a finite spot size. We propose the addition of an edge enhancement filter to the scanner, which compensates for the finite width of the optical beam. The proposed filter is designed to enhance the edges of the bar code so that for a given optical focusing it is possible to read higher density bar codes.

  17. Automatic Extraction of Road Markings from Mobile Laser Scanning Data

    Science.gov (United States)

    Ma, H.; Pei, Z.; Wei, Z.; Zhong, R.

    2017-09-01

    Road markings as critical feature in high-defination maps, which are Advanced Driver Assistance System (ADAS) and self-driving technology required, have important functions in providing guidance and information to moving cars. Mobile laser scanning (MLS) system is an effective way to obtain the 3D information of the road surface, including road markings, at highway speeds and at less than traditional survey costs. This paper presents a novel method to automatically extract road markings from MLS point clouds. Ground points are first filtered from raw input point clouds using neighborhood elevation consistency method. The basic assumption of the method is that the road surface is smooth. Points with small elevation-difference between neighborhood are considered to be ground points. Then ground points are partitioned into a set of profiles according to trajectory data. The intensity histogram of points in each profile is generated to find intensity jumps in certain threshold which inversely to laser distance. The separated points are used as seed points to region grow based on intensity so as to obtain road mark of integrity. We use the point cloud template-matching method to refine the road marking candidates via removing the noise clusters with low correlation coefficient. During experiment with a MLS point set of about 2 kilometres in a city center, our method provides a promising solution to the road markings extraction from MLS data.

  18. MULTI-WAVELENGTH AIRBORNE LASER SCANNING FOR ARCHAEOLOGICAL PROSPECTION

    Directory of Open Access Journals (Sweden)

    C. Briese

    2013-07-01

    Full Text Available Airborne laser scanning (ALS is a widely used technique for the sampling of the earth's surface. Next to the widely used geometric information current systems provide additional information about the signal strength of each echo. In order to utilize this information, radiometric calibration is essential. As a result physical observables that characterise the backscatter characteristic of the sensed surface are available. Due to the active illumination of the surfaces these values are independent of shadows caused by sunlight and due to the simultaneously recorded 3D information a single-channel true orthophoto can be directly estimated from the ALS data. By the combination of ALS data utilizing different laser wavelengths a multi-wavelength orthophoto of the scene can be generated. This contribution presents, next to the practical calibration workflow, the radiometric calibration results of the archaeological study site Carnuntum (Austria. The area has been surveyed at three different ALS wavelengths within a very short period of time. After the radiometric calibration of each single ALS wavelength (532 nm, 1064 nm and 1550 nm a multi-channel ALS orthophoto is derived. Subsequently, the radiometric calibration results of the single- and multi-wavelength ALS data are studied in respect to present archaeological features. Finally, these results are compared to the radiometric calibration results of an older ALS data acquisition campaign and to results of a systematic air photo interpretation.

  19. AUTOMATIC EXTRACTION OF ROAD MARKINGS FROM MOBILE LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    H. Ma

    2017-09-01

    Full Text Available Road markings as critical feature in high-defination maps, which are Advanced Driver Assistance System (ADAS and self-driving technology required, have important functions in providing guidance and information to moving cars. Mobile laser scanning (MLS system is an effective way to obtain the 3D information of the road surface, including road markings, at highway speeds and at less than traditional survey costs. This paper presents a novel method to automatically extract road markings from MLS point clouds. Ground points are first filtered from raw input point clouds using neighborhood elevation consistency method. The basic assumption of the method is that the road surface is smooth. Points with small elevation-difference between neighborhood are considered to be ground points. Then ground points are partitioned into a set of profiles according to trajectory data. The intensity histogram of points in each profile is generated to find intensity jumps in certain threshold which inversely to laser distance. The separated points are used as seed points to region grow based on intensity so as to obtain road mark of integrity. We use the point cloud template-matching method to refine the road marking candidates via removing the noise clusters with low correlation coefficient. During experiment with a MLS point set of about 2 kilometres in a city center, our method provides a promising solution to the road markings extraction from MLS data.

  20. PEDESTRIAN DETECTION BY LASER SCANNING AND DEPTH IMAGERY

    Directory of Open Access Journals (Sweden)

    A. Barsi

    2016-06-01

    Full Text Available Pedestrian flow is much less regulated and controlled compared to vehicle traffic. Estimating flow parameters would support many safety, security or commercial applications. Current paper discusses a method that enables acquiring information on pedestrian movements without disturbing and changing their motion. Profile laser scanner and depth camera have been applied to capture the geometry of the moving people as time series. Procedures have been developed to derive complex flow parameters, such as count, volume, walking direction and velocity from laser scanned point clouds. Since no images are captured from the faces of pedestrians, no privacy issues raised. The paper includes accuracy analysis of the estimated parameters based on video footage as reference. Due to the dense point clouds, detailed geometry analysis has been conducted to obtain the height and shoulder width of pedestrians and to detect whether luggage has been carried or not. The derived parameters support safety (e.g. detecting critical pedestrian density in mass events, security (e.g. detecting prohibited baggage in endangered areas and commercial applications (e.g. counting pedestrians at all entrances/exits of a shopping mall.

  1. Optical coherence tomography, scanning laser polarimetry and confocal scanning laser ophthalmoscopy in retinal nerve fiber layer measurements of glaucoma patients.

    Science.gov (United States)

    Fanihagh, Farsad; Kremmer, Stephan; Anastassiou, Gerasimos; Schallenberg, Maurice

    2015-01-01

    To determine the correlations and strength of association between different imaging systems in analyzing the retinal nerve fiber layer (RNFL) of glaucoma patients: optical coherence tomography (OCT), scanning laser polarimetry (SLP) and confocal scanning laser ophthalmoscopy (CSLO). 114 eyes of patients with moderate open angle glaucoma underwent spectral domain OCT (Topcon SD-OCT 2000 and Zeiss Cirrus HD-OCT), SLP (GDx VCC and GDx Pro) and CSLO (Heidelberg Retina Tomograph, HRT 3). Correlation coefficients were calculated between the structural parameters yielded by these examinations. The quantitative relationship between the measured RNFL thickness globally and for the four regions (superior, inferior, nasal, temporal) were evaluated with different regression models for all used imaging systems. The strongest correlation of RNFL measurements was found between devices using the same technology like GDx VCC and GDx Pro as well as Topcon OCT and Cirrus OCT. In glaucoma patients, the strongest associations (R²) were found between RNFL measurements of the two optical coherence tomography devices Topcon OCT and Cirrus OCT (R² = 0.513) and between GDx VCC and GDx Pro (R² = 0.451). The results of the OCTs and GDX Pro also had a strong quantitative relationship (Topcon OCT R² = 0.339 and Cirrus OCT R² = 0.347). GDx VCC and the OCTs showed a mild to moderate association (Topcon OCT R² = 0.207 and Cirrus OCT R² = 0.258). The confocal scanning laser ophthalmoscopy (HRT 3) had the lowest association to all other devices (Topcon OCT R² = 0.254, Cirrus OCT R² = 0.158, GDx Pro R² = 0.086 and GDx VCC R² = 0.1). The measurements of the RNFL in glaucoma patients reveal a high correlation of OCT and GDx devices because OCTs can measure all major retinal layers and SLP can detect nerve fibers allowing a comparison between the results of this devices. However, CSLO by means of HRT topography can only measure height values of the retinal surface but it cannot distinguish

  2. The Simulation Research on Capturing Time of Three Scanning Styles in Laser Tracking System

    OpenAIRE

    Leihong Zhang; Liujie Sun; Chunfang Wang; Zhen Liu

    2012-01-01

    In the optical communication, the choosing scanning style is important for the optical communication, because the illuminating laser beam is narrow and the communication range is long. In this study, three typical scanning styles of raster scan, spiral scan and square spiral scan are compared with each other. The characteristics of the scanning styles are introduced. The numerical simulation model is built. The capturing time at the same condition is computed. The capturing time is affected b...

  3. Detection of early interproximal caries in vitro using laser fluorescence, dye-enhanced laser fluorescence and direct visual examination.

    Science.gov (United States)

    Eggertsson, H; Analoui, M; van der Veen, M; González-Cabezas, C; Eckert, G; Stookey, G

    1999-01-01

    This in vitro study evaluated the use of laser fluorescence (LF) for the detection of early interproximal carious lesions and whether the detection could be enhanced using a fluorescent dye (DELF). Direct visual examination (DV) was used for comparison. Eighty extracted teeth were used, arranged in 20 blocks, each block having 2 premolars and 2 molars, lined up in a simulated sextant situation. After cleaning with a microabrasion kit, a subcontact window on half of the surfaces (60) was exposed to Carbopol white-spot solution for 5 days. The teeth were remounted in stone and examined by three independent examiners. For LF and DELF an argon laser was used (mixed wavelength of 488 and 514 nm) viewed through glasses (excluding wavelength stained with rhodamine B, and images were taken using a confocal microscope. The images were analyzed using a histogram program for lesion depth and image area. Lesions were present in 62 out of 120 approximal surfaces, with an average depth of 60 microm (range 17-190 microm). Sensitivity ranges for LF, DELF and DV were 56-74, 61-79 and 58-74%, and specificity ranges 67-78, 86-98 and 83-97%, respectively. With this model DELF compared favorably with DV and LF in sensitivity, but specificity was better for DELF and DV than for LF.

  4. Parametric modeling and optimization of laser scanning parameters during laser assisted machining of Inconel 718

    Science.gov (United States)

    Venkatesan, K.; Ramanujam, R.; Kuppan, P.

    2016-04-01

    This paper presents a parametric effect, microstructure, micro-hardness and optimization of laser scanning parameters (LSP) on heating experiments during laser assisted machining of Inconel 718 alloy. The laser source used for experiments is a continuous wave Nd:YAG laser with maximum power of 2 kW. The experimental parameters in the present study are cutting speed in the range of 50-100 m/min, feed rate of 0.05-0.1 mm/rev, laser power of 1.25-1.75 kW and approach angle of 60-90°of laser beam axis to tool. The plan of experiments are based on central composite rotatable design L31 (43) orthogonal array. The surface temperature is measured via on-line measurement using infrared pyrometer. Parametric significance on surface temperature is analysed using response surface methodology (RSM), analysis of variance (ANOVA) and 3D surface graphs. The structural change of the material surface is observed using optical microscope and quantitative measurement of heat affected depth that are analysed by Vicker's hardness test. The results indicate that the laser power and approach angle are the most significant parameters to affect the surface temperature. The optimum ranges of laser power and approach angle was identified as 1.25-1.5 kW and 60-65° using overlaid contour plot. The developed second order regression model is found to be in good agreement with experimental values with R2 values of 0.96 and 0.94 respectively for surface temperature and heat affected depth.

  5. Mechanisms of biliary stent clogging: confocal laser scanning and scanning electron microscopy.

    Science.gov (United States)

    van Berkel, A M; van Marle, J; Groen, A K; Bruno, M J

    2005-08-01

    Endoscopic insertion of plastic biliary endoprostheses is a well-established treatment for obstructive jaundice. The major limitation of this technique is late stent occlusion. In order to compare events involved in biliary stent clogging and identify the distribution of bacteria in unblocked stents, confocal laser scanning (CLS) and scanning electron microscopy (SEM) were carried out on two different stent materials - polyethylene (PE) and hydrophilic polymer-coated polyurethane (HCPC). Ten consecutive patients with postoperative benign biliary strictures were included in the study. Two 10-Fr stents 9 cm in length, one made of PE and the other of HCPC, were inserted. The stents were electively exchanged after 3 months and examined using CLS and SEM. No differences were seen between the two types of stent. The inner stent surface was covered with a uniform amorphous layer. On top of this layer, a biofilm of living and dead bacteria was found, which in most cases was unstructured. The lumen was filled with free-floating colonies of bacteria and crystals, surrounded by mobile laminar structures of mucus. An open network of large dietary fibers was seen in all of the stents. The same clogging events occurred in both PE and HCPC stents. The most remarkable observation was the identification of networks of large dietary fibers, resulting from duodenal reflux, acting as a filter. The build-up of this intraluminal framework of dietary fibers appears to be a major factor contributing to the multifactorial process of stent clogging.

  6. DEFORMATION MONITORING OF MOTORWAY UNDERPASSES USING LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    I. Puente

    2012-07-01

    deformation monitoring is a Optech Lynx mobile LiDAR. This laser scanner is based on time of flight technology and presents an accuracy of 6 mm in the determination of the geometrical coordinates. This accuracy can be improved to around 1 mm using fitting post-processing techniques and makes this technology very useful for studies related with deformation monitoring. The laser scanner, in comparison with other geodetic techniques as total stations, allows the control of all the structure, including unexpected deformations. Reflective targets are permanently positioned over the small walls of the structure to allow the 3D orientation of the different scans. Two main scans are made for this study, before and after the backfilling process. Backfilling takes about 10 days for the construction companies. The scans need a time of approximately 12 minutes. Construction works do not need to be interrupted during the scans. Point clouds are then post-processed using QT Modeler Software. First, the point cloud is cleaned to use only the data directly related with the structure under study. Then, using the target coordinates, both point clouds are moved to the same coordinate system. Finally, the deformation of the underpass is studied using two algorithms specifically developed using Matlab software. First algorithm fits a geometrical surface to the point cloud of the first scan and evaluates the residuals of both scans for this fitting surface. Differences in the residuals give the deformation map of the structure. Second algorithm takes a portion of the point cloud from the top of the structure, where it is located the joining point between the voussoirs. The joining between two voussoirs shows a height step that in an ideal case must tend to zero. Deformations produced by the loading of the structure are measured as a comparison between the steps before and after the backfilling process. The analysis of the results show as some deformation occurs in the structure in the joining

  7. Scanning laser topography and scanning laser polarimetry: comparing both imaging methods at same distances from the optic nerve head.

    Science.gov (United States)

    Kremmer, Stephan; Keienburg, Marcus; Anastassiou, Gerasimos; Schallenberg, Maurice; Steuhl, Klaus-Peter; Selbach, J Michael

    2012-01-01

    To compare the performance of scanning laser topography (SLT) and scanning laser polarimetry (SLP) on the rim of the optic nerve head and its surrounding area and thereby to evaluate whether these imaging technologies are influenced by other factors beyond the thickness of the retinal nerve fiber layer (RNFL). A total of 154 eyes from 5 different groups were examined: young healthy subjects (YNorm), old healthy subjects (ONorm), patients with normal tension glaucoma (NTG), patients with open-angle glaucoma and early glaucomatous damage (OAGE) and patients with open-angle glaucoma and advanced glaucomatous damage (OAGA). SLT and SLP measurements were taken. Four concentric circles were superimposed on each of the images: the first one measuring at the rim of the optic nerve head (1.0 ONHD), the next measuring at 1.25 optic nerve head diameters (ONHD), at 1.5 ONHD and at 1.75 ONHD. The aligned images were analyzed using GDx/NFA software. Both methods showed peaks of RNFL thickness in the superior and inferior segments of the ONH. The maximum thickness, registered by the SLT device was at the ONH rim where the SLP device tended to measure the lowest values. SLT measurements at the ONH were influenced by other tissues besides the RNFL like blood vessels and glial tissues. SLT and SLP were most strongly correlated at distances of 1.25 and 1.5 ONHD. While both imaging technologies are valuable tools in detecting glaucoma, measurements at the ONH rim should be interpreted critically since both methods might provide misleading results. For the assessment of the retinal nerve fiber layer we would like to recommend for both imaging technologies, SLT and SLP, measurements in 1.25 and 1.5 ONHD distance of the rim of the optic nerve head.

  8. A versatile fluorescence lifetime imaging system for scanning large areas with high time and spatial resolution

    Science.gov (United States)

    Bernardo, César; Belsley, Michael; de Matos Gomes, Etelvina; Gonçalves, Hugo; Isakov, Dmitry; Liebold, Falk; Pereira, Eduardo; Pires, Vladimiro; Samantilleke, Anura; Vasilevskiy, Mikhail; Schellenberg, Peter

    2014-08-01

    We present a flexible fluorescence lifetime imaging device which can be employed to scan large sample areas with a spatial resolution adjustable from many micrometers down to sub-micrometers and a temporal resolution of 20 picoseconds. Several different applications of the system will be presented including protein microarrays analysis, the scanning of historical samples, evaluation of solar cell surfaces and nanocrystalline organic crystals embedded in electrospun polymeric nanofibers. Energy transfer processes within semiconductor quantum dot superstructures as well as between dye probes and graphene layers were also investigated.

  9. Development of an Online Archive for Terrestrial Laser Scanning Data

    Science.gov (United States)

    Crosby, Christopher; Lowry, Ben; McWhirter, Jeff; Phillips, David; Meertens, Chuck

    2013-04-01

    The UNAVCO Geodetic Imaging program provides terrestrial laser scanning (TLS) support to the Earth science research community through a TLS instrumentation pool of five scanners, field engineering, data processing, and technical training. As part of this community TLS support role, UNAVCO is responsible for generation of level one (L1) TLS data products and TLS data archive and access. A UNAVCO-organized and US National Science Foundation-funded TLS community workshop held October 2011 in Boulder, Colorado defined many of the challenges and requirements a TLS data archive and access system must address. TLS data acquisition presents unique challenges for metadata, provenance capture, and data archive. TLS datasets are often large and level zero (L0 - raw) data are stored in a variety of proprietary formats, requiring conversion and standardization for access and exchange. Due to the wide range of scientific and engineering objectives that motivate TLS data collection, field methods and collection techniques vary greatly and must be thoroughly documented in project metadata. These challenges make data and metadata capture, preservation, and provenance important objectives for an online TLS archive. To address these challenges, UNAVCO is developing a TLS archive based on the open source RAMADDA platform (http://ramadda.org). The UNAVCO TLS archive will provide online archive of L0 and L1 data products, capture field metadata and data processing workflows for provenance, and store original georeferencing information. In addition, the TLS repository provides on-demand services for simple point cloud visualization, data sub-setting and thinning, and file format (e.g., LAS, ASCII, proprietary) data conversion. The system also offers automation of RINEX processing of GPS data, OPUS and CSRS submission and solution ingestion, and generation of control point lists to streamline georeferencing of TLS point cloud data. Georeferencing metadata and GPS file provenance are

  10. The fast and accurate 3D-face scanning technology based on laser triangle sensors

    Science.gov (United States)

    Wang, Jinjiang; Chang, Tianyu; Ge, Baozhen; Tian, Qingguo; Chen, Yang; Kong, Bin

    2013-08-01

    A laser triangle scanning method and the structure of 3D-face measurement system were introduced. In presented system, a liner laser source was selected as an optical indicated signal in order to scanning a line one times. The CCD image sensor was used to capture image of the laser line modulated by human face. The system parameters were obtained by system calibrated calculated. The lens parameters of image part of were calibrated with machine visual image method and the triangle structure parameters were calibrated with fine wire paralleled arranged. The CCD image part and line laser indicator were set with a linear motor carry which can achieve the line laser scanning form top of the head to neck. For the nose is ledge part and the eyes are sunk part, one CCD image sensor can not obtain the completed image of laser line. In this system, two CCD image sensors were set symmetric at two sides of the laser indicator. In fact, this structure includes two laser triangle measure units. Another novel design is there laser indicators were arranged in order to reduce the scanning time for it is difficult for human to keep static for longer time. The 3D data were calculated after scanning. And further data processing include 3D coordinate refine, mesh calculate and surface show. Experiments show that this system has simply structure, high scanning speed and accurate. The scanning range covers the whole head of adult, the typical resolution is 0.5mm.

  11. Benchmarking Naval Shipbuilding with 3D Laser Scanning, Additive Manufacturing, and Collaborative Product Lifecycle Management

    Science.gov (United States)

    2015-09-20

    can be developed to retrofit projects. • Asset and Facility Management/Documentation. With 3D documentation of complex factory and plant ...SPONSORED REPORT SERIES Benchmarking Naval Shipbuilding with 3D Laser Scanning, Additive Manufacturing, and Collaborative Product Lifecycle...Series Benchmarking Naval Shipbuilding with 3D Laser Scanning, Additive Manufacturing, and Collaborative Product Lifecycle Management 20 September

  12. Retinal nerve fiber layer assessment by scanning laser polarimetry and standardized photography

    NARCIS (Netherlands)

    Niessen, A. G.; van den Berg, T. J.; Langerhorst, C. T.; Greve, E. L.

    1996-01-01

    To determine whether, in a clinical setting, scanning laser polarimetry and retinal nerve fiber layer photography provide equivalent information on the retinal nerve fiber layer. We prospectively studied 60 patients with glaucoma or ocular hypertension and 24 healthy subjects. With scanning laser

  13. Tree Classification with Fused Mobile Laser Scanning and Hyperspectral Data

    Science.gov (United States)

    Puttonen, Eetu; Jaakkola, Anttoni; Litkey, Paula; Hyyppä, Juha

    2011-01-01

    Mobile Laser Scanning data were collected simultaneously with hyperspectral data using the Finnish Geodetic Institute Sensei system. The data were tested for tree species classification. The test area was an urban garden in the City of Espoo, Finland. Point clouds representing 168 individual tree specimens of 23 tree species were determined manually. The classification of the trees was done using first only the spatial data from point clouds, then with only the spectral data obtained with a spectrometer, and finally with the combined spatial and hyperspectral data from both sensors. Two classification tests were performed: the separation of coniferous and deciduous trees, and the identification of individual tree species. All determined tree specimens were used in distinguishing coniferous and deciduous trees. A subset of 133 trees and 10 tree species was used in the tree species classification. The best classification results for the fused data were 95.8% for the separation of the coniferous and deciduous classes. The best overall tree species classification succeeded with 83.5% accuracy for the best tested fused data feature combination. The respective results for paired structural features derived from the laser point cloud were 90.5% for the separation of the coniferous and deciduous classes and 65.4% for the species classification. Classification accuracies with paired hyperspectral reflectance value data were 90.5% for the separation of coniferous and deciduous classes and 62.4% for different species. The results are among the first of their kind and they show that mobile collected fused data outperformed single-sensor data in both classification tests and by a significant margin. PMID:22163894

  14. Use of hand-held laser scanning in the assessment of craniometry.

    Science.gov (United States)

    Park, Hee-Kyung; Chung, Jin-Woo; Kho, Hong-Seop

    2006-07-13

    The intra- and inter-examiner reliability was evaluated for hand-held 3D laser scanning technology when it was combined with localization of landmarks for craniometry. The data from the laser surface scanning were compared with those of conventional direct measuring. Using thirty unidentified skulls requested for individual identification, measurements were taken of the line distances from lambda to 26 landmarks, and also for seven breadth parameters. For the laser surface scanning, two examiners performed replicate measurements with an interval of 1 week. In the conventional direct measuring, the first examiner took replicate measurements with a 1-week interval. To assess intra- and inter-examiner reliabilities, the intraclass correlation coefficient was used. Analysis of variance with repeated measures for each parameter was performed to compare the conventional method with the 3D scanning method. Both the 3D scanning and conventional methods showed excellent intra-examiner reliabilities, and the 3D laser scanning method also showed excellent inter-examiner reliability. A statistical difference between the two examiners was found only in nasal breadth in the 3D laser scanning method. There was no significant difference between the two measuring methods, though the 3D laser scanning method tended to give a slightly lower reading. Collectively, the 3D laser scanning method with point localization is a useful method with excellent reliability, and it can replace the conventional direct measuring method in craniometry.

  15. Terrestrial Laser Scanning for Coastal Geomorphologic Research in Western Greece

    Science.gov (United States)

    Hoffmeister, D.; Tilly, N.; Curdt, C.; Aasen, H.; Ntageretzis, K.; Hadler, H.; Willershäuser, T.; Vött, A.; Bareth, G.

    2012-07-01

    We used terrestrial laser scanning (TLS) for (i) accurate volume estimations of dislocated boulders moved by high-energy impacts and for (ii) monitoring of annual coastal changes. In this contribution, we present three selected sites in Western Greece that were surveyed during a time span of four years (2008-2011). The Riegl LMS-Z420i laser scanner was used in combination with a precise DGPS system (Topcon HiPer Pro). Each scan position and a further target were recorded for georeferencing and merging of the point clouds. For the annual detection of changes, reference points for the base station of the DGPS system were marked. Our studies show that TLS is capable to accurately estimate volumes of boulders, which were dislocated and deposited inland from the littoral zone. The mass of each boulder was calculated from this 3D-reconstructed volume and according density data. The masses turned out to be considerably smaller than common estimated masses based on tape-measurements and according density approximations. The accurate mass data was incorporated into wave transport equations, which estimate wave velocities of high-energy impacts. As expected, these show smaller wave velocities, due to the incorporated smaller mass. Furthermore, TLS is capable to monitor annual changes on coastal areas. The changes are detected by comparing high resolution digital elevation models from every year. On a beach site, larger areas of sea-weed and sandy sediments are eroded. In contrast, bigger gravel with 30-50 cm diameter was accumulated. At the other area with bigger boulders and a different coastal configuration only slightly differences were detectable. In low-lying coastal areas and along recent beaches, post-processing of point clouds turned out to be more difficult, due to noise effects by water and shadowing effects. However, our studies show that the application of TLS in different littoral settings is an appropriate and promising tool. The combination of both instruments

  16. Deformation Monitoring of Motorway Underpasses Using Laser Scanning Data

    Science.gov (United States)

    Puente, I.; González-Jorge, H.; Riveiro, B.; Arias, P.

    2012-07-01

    is a Optech Lynx mobile LiDAR. This laser scanner is based on time of flight technology and presents an accuracy of 6 mm in the determination of the geometrical coordinates. This accuracy can be improved to around 1 mm using fitting post-processing techniques and makes this technology very useful for studies related with deformation monitoring. The laser scanner, in comparison with other geodetic techniques as total stations, allows the control of all the structure, including unexpected deformations. Reflective targets are permanently positioned over the small walls of the structure to allow the 3D orientation of the different scans. Two main scans are made for this study, before and after the backfilling process. Backfilling takes about 10 days for the construction companies. The scans need a time of approximately 12 minutes. Construction works do not need to be interrupted during the scans. Point clouds are then post-processed using QT Modeler Software. First, the point cloud is cleaned to use only the data directly related with the structure under study. Then, using the target coordinates, both point clouds are moved to the same coordinate system. Finally, the deformation of the underpass is studied using two algorithms specifically developed using Matlab software. First algorithm fits a geometrical surface to the point cloud of the first scan and evaluates the residuals of both scans for this fitting surface. Differences in the residuals give the deformation map of the structure. Second algorithm takes a portion of the point cloud from the top of the structure, where it is located the joining point between the voussoirs. The joining between two voussoirs shows a height step that in an ideal case must tend to zero. Deformations produced by the loading of the structure are measured as a comparison between the steps before and after the backfilling process. The analysis of the results show as some deformation occurs in the structure in the joining point of the

  17. Laser-induced fluorescence with an OPO system. Part II: direct determination of lead content in seawater by electrothermal atomization-laser-excited atomic fluorescence (ETA-LEAF).

    Science.gov (United States)

    Le Bihan, A; Lijour, Y; Giamarchi, P; Burel-Deschamps, L; Stephan, L

    2003-03-01

    Fluorescence was induced by coupling a laser with an optical parametric oscillator (OPO) to develop an analytical method for the direct determination of lead content, at ultra-trace level, in seawater by electrothermal atomization-laser-excited atomic fluorescence (ETA-LEAF). The optimization of atomization conditions, laser pulse energy, and mainly temporal parameters allowed us to reach a 3 fg detection limit (0.3 ng L(-1)) despite the low repetition rate of the device. The expected error on predicted concentrations of lead, at trace levels, in seawater was below 15%.

  18. Calibration of Mounted Parameter for Ship-borne 3D Laser Scanning System

    Directory of Open Access Journals (Sweden)

    XU Wenxue

    2018-02-01

    Full Text Available Ship-borne 3D laser scanning technology has vital theoretical significance and practical value in marine surveying and mapping.As one of the key steps of ship-borne 3D laser scanning, calibration of mounted parameter is urgent to be solved.This paper proposes a calibration method of mounted parameter without control points for ship-borne 3D laser scanning system.Based on the corresponding points in overlapping area, mounted parameter calibration model of scan system is built by time and spatia registration model of ship-borne 3D laser scanning data.Finally, differential least squares are applied to obtain optimum mounted parameters.Experiments demonstrate the reasonable and effectiveness of this method,the quality of scanning data can be significantly improved.

  19. Multispectral scanning laser ophthalmoscopy combined with optical coherence tomography for simultaneous in vivo mouse retinal imaging

    Science.gov (United States)

    Zhang, Pengfei; Zam, Azhar; Jian, Yifan; Wang, Xinlei; Burns, Marie E.; Sarunic, Marinko V.; Pugh, Edward N.; Zawadzki, Robert J.

    2015-03-01

    A compact, non-invasive multi-modal system has been developed for in vivo mouse retina imaging. It is configured for simultaneously detecting green and red fluorescent protein signals with scanning laser ophthalmoscopy (SLO) back-scattered light from the SLO illumination beam, and depth information about different retinal layers by means of Optical Coherence Tomography (OCT). Simultaneous assessment of retinal characteristics with different modalities can provide a wealth of information about the structural and functional changes in the retinal neural tissue and chorio-retinal vasculature in vivo. Additionally, simultaneous acquisition of multiple channels facilitates analysis of the data of different modalities by automatic temporal and structural co-registration. As an example of the instrument's performance we imaged the retina of a mouse with constitutive expression of GFP in microglia cells (Cx3cr1GFP/+), and which also expressed the red fluorescent protein mCherry in Müller glial cells by means of adeno-associated virus delivery (AAV2) of an mCherry cDNA driven by the GFAP (glial fibrillary acid protein) promoter.

  20. TRACE ANALYSIS BY LASER-EXCITED ATOMIC FLUORESCENCE WITH ATOMIZATION IN A PULSED PLASMA

    OpenAIRE

    Lunyov , O.; Oshemkov , S.; Petrov , A.

    1991-01-01

    The possibilities of plasma atomization for laser fluorescence trace analysis are discussed. Pulsed hot hollow cathode discharge was used for analysis of solutions and powdered samples. The high voltage spark and laser-induced breakdown (laser spark) were used as atomizers of metal-containing atmospheric aerosols. Detection limits were improved by means of temporal background selection.

  1. An Analytical and Experimental Investigation of Average Laser Power and Angular Scanning Speed Effects on Laser Tube Bending Process

    Directory of Open Access Journals (Sweden)

    Imhan Khalil Ibraheem

    2017-01-01

    Full Text Available Laser tube bending is a new technique of laser material forming to produce a complex and accurate shape due to its flexibility and high controllability. Moreover, the defects during conventional tube forming such as thinning, wrinkling, spring back and ovalization can be avoided in laser tube bending process, because there is no external force used. In this paper an analytical investigation has been conducted to analyses the effects of average laser power and laser scanning speed on laser tube bending process, the analytical results have been verified experimentally. The model used in this study is in the same trend of the experiment. The results show that the bending angle increased with the increasing of average laser power and decreased with the increasing of angular scanning speed.

  2. An Automated Road Roughness Detection from Mobile Laser Scanning Data

    Science.gov (United States)

    Kumar, P.; Angelats, E.

    2017-05-01

    Rough roads influence the safety of the road users as accident rate increases with increasing unevenness of the road surface. Road roughness regions are required to be efficiently detected and located in order to ensure their maintenance. Mobile Laser Scanning (MLS) systems provide a rapid and cost-effective alternative by providing accurate and dense point cloud data along route corridor. In this paper, an automated algorithm is presented for detecting road roughness from MLS data. The presented algorithm is based on interpolating smooth intensity raster surface from LiDAR point cloud data using point thinning process. The interpolated surface is further processed using morphological and multi-level Otsu thresholding operations to identify candidate road roughness regions. The candidate regions are finally filtered based on spatial density and standard deviation of elevation criteria to detect the roughness along the road surface. The test results of road roughness detection algorithm on two road sections are presented. The developed approach can be used to provide comprehensive information to road authorities in order to schedule maintenance and ensure maximum safety conditions for road users.

  3. MEASURING LEAF WATER CONTENT USING MULTISPECTRAL TERRESTRIAL LASER SCANNING

    Directory of Open Access Journals (Sweden)

    S. Junttila

    2017-10-01

    Full Text Available Climate change is increasing the amount and intensity of disturbance events, i.e. drought, pest insect outbreaks and fungal pathogens, in forests worldwide. Leaf water content (LWC is an early indicator of tree stress that can be measured remotely using multispectral terrestrial laser scanning (MS-TLS. LWC affects leaf reflectance in the shortwave infrared spectrum which can be used to predict LWC from spatially explicit MS-TLS intensity data. Here, we investigated the relationship between LWC and MS-TLS intensity features at 690 nm, 905 nm and 1550 nm wavelengths with Norway spruce seedlings in greenhouse conditions. We found that a simple ratio of 905 nm and 1550 nm wavelengths was able to explain 84 % of the variation (R2 in LWC with a respective prediction accuracy of 0.0041 g/cm2. Our results showed that MS-TLS can be used to estimate LWC with a reasonable accuracy in environmentally stable conditions.

  4. Measuring Leaf Water Content Using Multispectral Terrestrial Laser Scanning

    Science.gov (United States)

    Junttila, S.; Vastaranta, M.; Linnakoski, R.; Sugano, J.; Kaartinen, H.; Kukko, A.; Holopainen, M.; Hyyppä, H.; Hyyppä, J.

    2017-10-01

    Climate change is increasing the amount and intensity of disturbance events, i.e. drought, pest insect outbreaks and fungal pathogens, in forests worldwide. Leaf water content (LWC) is an early indicator of tree stress that can be measured remotely using multispectral terrestrial laser scanning (MS-TLS). LWC affects leaf reflectance in the shortwave infrared spectrum which can be used to predict LWC from spatially explicit MS-TLS intensity data. Here, we investigated the relationship between LWC and MS-TLS intensity features at 690 nm, 905 nm and 1550 nm wavelengths with Norway spruce seedlings in greenhouse conditions. We found that a simple ratio of 905 nm and 1550 nm wavelengths was able to explain 84 % of the variation (R2) in LWC with a respective prediction accuracy of 0.0041 g/cm2. Our results showed that MS-TLS can be used to estimate LWC with a reasonable accuracy in environmentally stable conditions.

  5. Detecting Terrain Stoniness From Airborne Laser Scanning Data †

    Directory of Open Access Journals (Sweden)

    Paavo Nevalainen

    2016-08-01

    Full Text Available Three methods to estimate the presence of ground surface stones from publicly available Airborne Laser Scanning (ALS point clouds are presented. The first method approximates the local curvature by local linear multi-scale fitting, and the second method uses Discrete-Differential Gaussian curvature based on the ground surface triangulation. The third baseline method applies Laplace filtering to Digital Elevation Model (DEM in a 2 m regular grid data. All methods produce an approximate Gaussian curvature distribution which is then vectorized and classified by logistic regression. Two training data sets consisted of 88 and 674 polygons of mass-flow deposits, respectively. The locality of the polygon samples is a sparse canopy boreal forest, where the density of ALS ground returns is sufficiently high to reveal information about terrain micro-topography. The surface stoniness of each polygon sample was categorized for supervised learning by expert observation on the site. The leave-pair-out (L2O cross-validation of the local linear fit method results in the area under curve A U C = 0 . 74 and A U C = 0 . 85 on two data sets, respectively. This performance can be expected to suit real world applications such as detecting coarse-grained sediments for infrastructure construction. A wall-to-wall predictor based on the study was demonstrated.

  6. Structural damage detection and estimation using a scanning laser vibrometer

    Science.gov (United States)

    Pai, Perngjin F.; Lee, Seung-Yoon; Schulz, Mark J.

    2001-07-01

    This paper presents a model-independent boundary effect evaluation (BEE) method for pinpointing crack locations and estimating crack sizes using only operational deflection shapes (ODSs) measured by a scanning laser vibrometer. An ODS consists of central and boundary solutions. Central solutions are periodic functions, and boundary solutions are exponentially decaying functions due to boundary constraints. The BEE method uses a sliding-window curve-fitting technique to extract boundary solutions from an experimental ODS. Because cracks introduce localized small boundaries to a structure, boundary solutions exist around cracks as well as structural boundaries. Since crack-induced boundary solutions show characteristics different from those of actual boundaries, cracks can be easily located. A local strain energy method is derived for estimating crack sizes. In the method, the crack-induced strain energy extracted from an ODS is compared with the one calculated using fracture mechanics to estimate the crack size. To verify the capability and accuracy of this BEE method, experiments are performed on six 22' X 1' X 0.25' 2024-T4 aluminum beams each having a through-the-width Mode I crack at its midpoint. These cracks are slots having a width of 0.039' and depths of 0.0625' (25% of the beam thickness), 0.05' (20%), 0.0375' (15%), 0.025' (10%), 0.0125' (5%), and 0.005' (2%), respectively. Results show that this BEE method is capable of locating and estimating small cracks.

  7. Monitoring Riverbank Erosion in Mountain Catchments Using Terrestrial Laser Scanning

    Directory of Open Access Journals (Sweden)

    Laura Longoni

    2016-03-01

    Full Text Available Sediment yield is a key factor in river basins management due to the various and adverse consequences that erosion and sediment transport in rivers may have on the environment. Although various contributions can be found in the literature about sediment yield modeling and bank erosion monitoring, the link between weather conditions, river flow rate and bank erosion remains scarcely known. Thus, a basin scale assessment of sediment yield due to riverbank erosion is an objective hard to be reached. In order to enhance the current knowledge in this field, a monitoring method based on high resolution 3D model reconstruction of riverbanks, surveyed by multi-temporal terrestrial laser scanning, was applied to four banks in Val Tartano, Northern Italy. Six data acquisitions over one year were taken, with the aim to better understand the erosion processes and their triggering factors by means of more frequent observations compared to usual annual campaigns. The objective of the research is to address three key questions concerning bank erosion: “how” erosion happens, “when” during the year and “how much” sediment is eroded. The method proved to be effective and able to measure both eroded and deposited volume in the surveyed area. Finally an attempt to extrapolate basin scale volume for bank erosion is presented.

  8. Multi-Pass Approach for Mobile Terrestrial Laser Scanning

    Science.gov (United States)

    Nolan, J.; Eckels, R.; Evers, M.; Singh, R.; Olsen, M. J.

    2015-08-01

    Mobile Terrestrial Laser Scanning (MTLS) has been utilised for an increasing number of corridor surveys. Current MTLS surveys require that many targets be placed along the corridor to monitor the MTLS trajectory's accuracy. These targets enable surveyors to directly evaluate the magnitude of GNSS errors at regular intervals and can also be used to adjust the trajectory to the survey control. However, this "Multi-Target" approach (MTA) is an onerous task that can significantly reduce efficiency. It also is inconvenient to the travelling public, as lanes are often blocked and traffic slowed to permit surveyors to work safely along the road corridor. This paper introduces a "Multi-Pass" approach (MPA), which minimises the number of targets required for monitoring the GNSS-controlled trajectory while still maintaining strict engineering accuracies. MPA uses the power of multiple, independent MTLS passes with different GNSS constellations to generate a "Control Polyline" from the point cloud for the corridor. The Control Polyline can be considered as a statistically valid survey measurement and be incorporated in a network adjustment to strengthen a control network by identifying outliers. Results from a test survey at the MTLS course maintained by the Oregon Department of Transportation illustrate the effectiveness of this approach.

  9. Laser scanning dental probe for endodontic root canal treatment

    Science.gov (United States)

    Blank, Molly A. B.; Friedrich, Michal; Hamilton, Jeffrey D.; Lee, Peggy; Berg, Joel; Seibel, Eric J.

    2011-03-01

    Complications that arise during endodontic procedures pose serious threats to the long-term integrity and health of the tooth. Potential complexities of root canals include residual pulpal tissue, cracks, mesial-buccal 2 and accessory canals. In the case of a failed root canal, a successful apicoectomy can be jeopardized by isthmuses, accessory canals, and root microfracture. Confirming diagnosis using a small imaging probe would allow proper treatment and prevent retreatment of endodontic procedures. An ultrathin and flexible laser scanning endoscope of 1.2 to 1.6mm outer diameter was used in vitro to image extracted teeth with varied root configurations. Teeth were opened using a conventional bur and high speed drill. Imaging within the opened access cavity clarified the location of the roots where canal filing would initiate. Although radiographs are commonly used to determine the root canal size, position, and shape, the limited 2D image perspective leaves ambiguity that could be clarified if used in conjunction with a direct visual imaging tool. Direct visualization may avoid difficulties in locating the root canal and reduce the number of radiographs needed. A transillumination imaging device with the separated illumination and light collection functions rendered cracks visible in the prepared teeth that were otherwise indiscernible using reflected visible light. Our work demonstrates that a small diameter endoscope with high spatial resolution may significantly increase the efficiency and success of endodontic procedures.

  10. Probing cytotoxicity of nanoparticles and organic compounds using scanning proton microscopy, scanning electron microscopy and fluorescence microscopy

    International Nuclear Information System (INIS)

    Tong Yongpeng; Li Changming; Liang Feng; Chen Jianmin; Zhang Hong; Liu Guoqing; Sun Huibin; Luong, John H.T.

    2008-01-01

    Scanning proton microscopy, scanning electron microscopy (SEM) and fluorescence microscopy have been used to probe the cytotoxicity effect of benzo[a]pyrene (BaP), ethidium bromide (EB) and nanoparticles (ZnO, Al 2 O 3 and TiO 2 ) on a T lymphoblastic leukemia Jurkat cell line. The increased calcium ion (from CaCl 2 ) in the culture medium stimulated the accumulation of BaP and EB inside the cell, leading to cell death. ZnO, Al 2 O 3 and TiO 2 nanoparticles, however, showed a protective effect against these two organic compounds. Such inorganic nanoparticles complexed with BaP or EB which became less toxic to the cell. Fe 2 O 3 nanoparticles as an insoluble particle model scavenged by macrophage were investigated in rats. They were scavenged out of the lung tissue about 48 h after infection. This result suggest that some insoluble inorganic nanoparticles of PM (particulate matters) showed protective effects on organic toxins induced acute toxic effects as they can be scavenged by macrophage cells. Whereas, some inorganic ions such as calcium ion in PM may help environmental organic toxins to penetrate cell membrane and induce higher toxic effect.

  11. Probing cytotoxicity of nanoparticles and organic compounds using scanning proton microscopy, scanning electron microscopy and fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tong Yongpeng [Institute of Nuclear Techniques, Shenzhen University, Nanhai Avenue 3688, Shenzhen 518060 (China)], E-mail: yongpengt@yahoo.com.cn; Li Changming [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457 (Singapore); Liang Feng [Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200025 (China); Chen Jianmin [Shenzhen Municipal Hospital for Chronic Disease Control and Prevention, Guangdong 518020 (China); Zhang Hong; Liu Guoqing; Sun Huibin [Institute of Nuclear Techniques, Shenzhen University, Nanhai Avenue 3688, Shenzhen 518060 (China); Luong, John H.T. [Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, H4P 2R2 (Canada)

    2008-12-15

    Scanning proton microscopy, scanning electron microscopy (SEM) and fluorescence microscopy have been used to probe the cytotoxicity effect of benzo[a]pyrene (BaP), ethidium bromide (EB) and nanoparticles (ZnO, Al{sub 2}O{sub 3} and TiO{sub 2}) on a T lymphoblastic leukemia Jurkat cell line. The increased calcium ion (from CaCl{sub 2}) in the culture medium stimulated the accumulation of BaP and EB inside the cell, leading to cell death. ZnO, Al{sub 2}O{sub 3} and TiO{sub 2} nanoparticles, however, showed a protective effect against these two organic compounds. Such inorganic nanoparticles complexed with BaP or EB which became less toxic to the cell. Fe{sub 2}O{sub 3} nanoparticles as an insoluble particle model scavenged by macrophage were investigated in rats. They were scavenged out of the lung tissue about 48 h after infection. This result suggest that some insoluble inorganic nanoparticles of PM (particulate matters) showed protective effects on organic toxins induced acute toxic effects as they can be scavenged by macrophage cells. Whereas, some inorganic ions such as calcium ion in PM may help environmental organic toxins to penetrate cell membrane and induce higher toxic effect.

  12. The binding of cellulase variants to dislocations: a semi-quantitative analysis based on CLSM (confocal laser scanning microscopy) images

    DEFF Research Database (Denmark)

    Hidayat, Budi J.; Weisskopf, Carmen; Felby, Claus

    2015-01-01

    or slip planes. Here we study whether cellulases bind to dislocations to a higher extent than to the surrounding cell wall. The binding of fluorescently labelled cellobiohydrolases and endoglucanases to filter paper fibers was investigated using confocal laser scanning microscopy and a ratiometric method...... was developed to assess and quantify the abundance of the binding of cellulases to dislocations as compared to the surrounding cell wall. Only Humicola insolens EGV was found to have stronger binding preference to dislocations than to the surrounding cell wall, while no difference in binding affinity was seen...

  13. Modelling and calibration of the laser beam-scanning triangulation measurement system

    NARCIS (Netherlands)

    Wang, G.Y.; Zheng, Bing; Li, Xin; Houkes, Z.; Regtien, Paulus P.L.

    2002-01-01

    We present an approach of modelling and calibration of an active laser beam-scanning triangulation measurement system. The system works with the pattern of two-dimensional beam-scanning illumination and one-dimensional slit-scanning detection with a photo-multiplier tube instead of a CCD camera. By

  14. Multispectral imaging system based on laser-induced fluorescence for security applications

    Science.gov (United States)

    Caneve, L.; Colao, F.; Del Franco, M.; Palucci, A.; Pistilli, M.; Spizzichino, V.

    2016-10-01

    The development of portable sensors for fast screening of crime scenes is required to reduce the number of evidences useful to be collected, optimizing time and resources. Laser based spectroscopic techniques are good candidates to this scope due to their capability to operate in field, in remote and rapid way. In this work, the prototype of a multispectral imaging LIF (Laser Induced Fluorescence) system able to detect evidence of different materials on large very crowded and confusing areas at distances up to some tens of meters will be presented. Data collected as both 2D fluorescence images and LIF spectra are suitable to the identification and the localization of the materials of interest. A reduced scan time, preserving at the same time the accuracy of the results, has been taken into account as a main requirement in the system design. An excimer laser with high energy and repetition rate coupled to a gated high sensitivity ICCD assures very good performances for this purpose. Effort has been devoted to speed up the data processing. The system has been tested in outdoor and indoor real scenarios and some results will be reported. Evidence of the plastics polypropylene (PP) and polyethilene (PE) and polyester have been identified and their localization on the examined scenes has been highlighted through the data processing. By suitable emission bands, the instrument can be used for the rapid detection of other material classes (i.e. textiles, woods, varnishes). The activities of this work have been supported by the EU-FP7 FORLAB project (Forensic Laboratory for in-situ evidence analysis in a post blast scenario).

  15. Evaluation of a laser-induced fluorescence system for uranium analysis

    Energy Technology Data Exchange (ETDEWEB)

    White, L.E.

    1980-05-01

    A laser-induced fluorescence method for total uranium analysis of industrial process waters, waste waters, and leachates has been evaluated as a possible alternative for the normal, sodium fluoride and lithium fluoride, flame-fusion fluorescence method currently employed. Since the lower reporting limit of the laser fluorometer is on the order of 0.05 ..mu..g/L, samples for normal analysis can usually be diluted from 100 to 1000 fold which virtually eliminates interferences from quenching substances. Also, since the uranium determination is done in aqueous solution, laser-induced fluorescence entirely eliminates the need for organic extraction and the subsequent fusion process.

  16. A laser fluorescence anemometer system for the Langley 16- by 24-inch water tunnel

    Science.gov (United States)

    Owen, F. K.; Orngard, Gary M.; Neuhart, Dan H.

    1991-01-01

    A laser fluorescence anemometer which comprises a three-component laser Doppler velocimeter system with a fourth channel to measure fluorescent dye concentration has been installed in the NASA Langley 16- by 24-in water tunnel. The system includes custom designed optics, data acquisition, and traverse control instruments and a custom software package. Feasibility studies demonstrated how water tunnels can be used in conjunction with advanced optical techniques to provide nonintrusive detailed flow field measurements of complex fluid flows with a minimum of expense. The measurements show that the laser fluorescence anemometer can provide new insight into the structure, entrainment, control and of mixing vortical and shear layer flows.

  17. The implementation of laser speckle reduction based on MEMS two-dimensional scanning mirror

    Science.gov (United States)

    Wang, Tingting; Shen, Wenjiang; Wu, Shengli; Zhou, Peng; He, Jiahui; Yu, Huijun

    2016-10-01

    Laser speckle on the screen of laser display system is due to the strong coherence characteristic of laser. In order to eliminate the influence of the speckle on image quality, the method of laser speckle reduction based on MEMS two-dimensional scanning mirror is proposed in this paper. The experimental results show that the speckle contrast can be reduced to 3.7%, which meets the requirement of laser display. And this system could be used in laser display field and improve the display performance.

  18. Experimental Research of Reliability of Plant Stress State Detection by Laser-Induced Fluorescence Method

    Directory of Open Access Journals (Sweden)

    Yury Fedotov

    2016-01-01

    Full Text Available Experimental laboratory investigations of the laser-induced fluorescence spectra of watercress and lawn grass were conducted. The fluorescence spectra were excited by YAG:Nd laser emitting at 532 nm. It was established that the influence of stress caused by mechanical damage, overwatering, and soil pollution is manifested in changes of the spectra shapes. The mean values and confidence intervals for the ratio of two fluorescence maxima near 685 and 740 nm were estimated. It is presented that the fluorescence ratio could be considered a reliable characteristic of plant stress state.

  19. Time-resolved resonance fluorescence spectroscopy for study of chemical reactions in laser-induced plasmas.

    Science.gov (United States)

    Liu, Lei; Deng, Leimin; Fan, Lisha; Huang, Xi; Lu, Yao; Shen, Xiaokang; Jiang, Lan; Silvain, Jean-François; Lu, Yongfeng

    2017-10-30

    Identification of chemical intermediates and study of chemical reaction pathways and mechanisms in laser-induced plasmas are important for laser-ablated applications. Laser-induced breakdown spectroscopy (LIBS), as a promising spectroscopic technique, is efficient for elemental analyses but can only provide limited information about chemical products in laser-induced plasmas. In this work, time-resolved resonance fluorescence spectroscopy was studied as a promising tool for the study of chemical reactions in laser-induced plasmas. Resonance fluorescence excitation of diatomic aluminum monoxide (AlO) and triatomic dialuminum monoxide (Al 2 O) was used to identify these chemical intermediates. Time-resolved fluorescence spectra of AlO and Al 2 O were used to observe the temporal evolution in laser-induced Al plasmas and to study their formation in the Al-O 2 chemistry in air.

  20. Precision scan-imaging for paperboard quality inspection utilizing X-ray fluorescence

    Science.gov (United States)

    Norlin, B.; Reza, S.; Fröjdh, C.; Nordin, T.

    2018-01-01

    Paperboard is typically made up of a core of cellulose fibers [C6H10O5] and a coating layer of [CaCO3]. The uniformity of these layers is a critical parameter for the printing quality. Current quality control methods include chemistry based visual inspection methods as well as X-ray based methods to measure the coating thickness. In this work we combine the X-ray fluorescence signals from the Ca atoms (3.7 keV) in the coating and from a Cu target (8.0 keV) placed behind the paper to simultaneously measure both the coating and the fibers. Cu was selected as the target material since its fluorescence signal is well separated from the Ca signal while its fluorescence's still are absorbed sufficiently in the paper. A laboratory scale setup is built using stepper motors, a silicon drift detector based spectrometer and a collimated X-ray beam. The spectroscopic image is retrieved by scanning the paperboard surface and registering the fluorescence signals from Ca and Cu. The exposure time for this type of setups can be significantly improved by implementing spectroscopic imaging sensors. The material contents in the layers can then be retrieved from the absolute and relative intensities of these two signals.

  1. Fluorescent nanoscale detection of biotin-streptavidin interaction using near-field scanning optical microscopy

    International Nuclear Information System (INIS)

    Park, Hyun Kyu; Chung, Bong Hyun; Gokarna, Anisha; Hulme, John P; Park, Hyun Gyu

    2008-01-01

    We describe a nanoscale strategy for detecting biotin-streptavidin binding using near-field scanning optical microscopy (NSOM) that exploits the fluorescence properties of single polydiacetylene (PDA) liposomes. NSOM is more useful to observe nanomaterials having optical properties with the help of topological information. We synthesized amine-terminated 10,12-pentacosadiynoic acid (PCDA) monomer (PCDA-NH 2 ) and used this derivatized monomer to prepare PCDA liposomes. PCDA-NH 2 liposomes were immobilized on an aldehyde-functionalized glass surface followed by photopolymerization by using a 254 nm light source. To measure the biotin-streptavidin binding, we conjugated photoactivatable biotin to immobilized PCDA-NH 2 liposomes by UV irradiation (365 nm) and subsequently allowed them to interact with streptavidin. We analyzed the fluorescence using a fluorescence scanner and observed single liposomes using NSOM. The average height and NSOM signal observed in a single liposome after binding were ∼31.3 to 8.5 ± 0.5 nm and 0.37 to 0.16 ± 0.6 kHz, respectively. This approach, which has the advantage of not requiring a fluorescent label, could prove highly beneficial for single molecule detection technology

  2. RANSAC approach for automated registration of terrestrial laser scans using linear features

    Directory of Open Access Journals (Sweden)

    K. Al-Durgham

    2013-10-01

    Full Text Available The registration process of terrestrial laser scans (TLS targets the problem of how to combine several laser scans in order to attain better information about features than what could be obtained through single scan. The main goal of the registration process is to estimate the parameters which determine geometrical variation between the origins of datasets collected from different locations. Scale, shifts, and rotation parameters are usually used to describe such variation. This paper presents a framework for the registration of overlapping terrestrial laser scans by establishing an automatic matching strategy that uses 3D linear features. More specifically, invariant separation characteristics between 3D linear features extracted from laser scans will be used to establish hypothesized conjugate linear features between the laser scans. These candidate matches are then used to geo-reference scans relative to a common reference frame. The registration workflow simulates the well-known RANndom Sample Consensus method (RANSAC for determining the registration parameters, whereas the iterative closest projected point (ICPP is utilized to determine the most probable solution of the transformation parameters from several solutions. The experimental results prove that the proposed methodology can be used for the automatic registration of terrestrial laser scans using linear features.

  3. Cosmetic and aesthetic skin photosurgery using a computer-assisted CO2 laser-scanning system

    Science.gov (United States)

    Dutu, Doru C. A.; Dumitras, Dan C.; Nedelcu, Ioan; Ghetie, Sergiu D.

    1997-12-01

    Since the first application of CO2 laser in skin photosurgery, various techniques such as laser pulsing, beam scanning and computer-assisted laser pulse generator have been introduced for the purpose of reducing tissue carbonization and thermal necrosis. Using a quite simple XY optical scanner equipped with two galvanometric driven mirrors and an appropriate software to process the scanning data and control the interaction time and energy density in the scanned area, we have obtained a device which can improve CO2 laser application in cosmetic and aesthetic surgery. The opto-mechanical CO2 laser scanner based on two total reflecting flat mirrors placed at 90 degree(s) in respect to the XY scanning directions and independently driven through a magnetic field provides a linear movement of the incident laser beam in the operating field. A DA converter supplied with scanning data by the software enables a scanning with linearity better than 1% for a maximum angular deviation of 20 degree(s). Because the scanning quality of the laser beam in the operating field is given not only by the displacement function of the two mirrors, but also by the beam characteristics in the focal plane and the cross distribution in the laser beam, the surgeon can control through software either the scanning field dimensions or the distance between two consecutive points of the vertically and/or horizontally sweep line. The development of computer-assisted surgical scanning techniques will help control the surgical laser, to create either a reproducible incision with a controlled depth or a controlled incision pattern with minimal incision width, a long desired facility for plastic surgery, neurosurgery, ENT and dentistry.

  4. Correlative Fluorescence and Electron Microscopy in 3D-Scanning Electron Microscope Perspective.

    Science.gov (United States)

    Franks, Jonathan; Wallace, Callen T; Shibata, Masateru; Suga, Mitsuo; Erdman, Natasha; Stolz, Donna B; Watkins, Simon C

    2017-04-03

    The ability to correlate fluorescence microscopy (FM) and electron microscopy (EM) data obtained on biological (cell and tissue) specimens is essential to bridge the resolution gap between the data obtained by these different imaging techniques. In the past such correlations were limited to either EM navigation in two dimensions to the locations previously highlighted by fluorescence markers, or subsequent high-resolution acquisition of tomographic information using a TEM. We present a novel approach whereby a sample previously investigated by FM is embedded and subjected to sequential mechanical polishing and backscatter imaging by scanning electron microscope. The resulting three dimensional EM tomogram of the sample can be directly correlated to the FM data. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  5. Modeling Mediterranean forest structure using airborne laser scanning data

    Science.gov (United States)

    Bottalico, Francesca; Chirici, Gherardo; Giannini, Raffaello; Mele, Salvatore; Mura, Matteo; Puxeddu, Michele; McRoberts, Ronald E.; Valbuena, Ruben; Travaglini, Davide

    2017-05-01

    The conservation of biological diversity is recognized as a fundamental component of sustainable development, and forests contribute greatly to its preservation. Structural complexity increases the potential biological diversity of a forest by creating multiple niches that can host a wide variety of species. To facilitate greater understanding of the contributions of forest structure to forest biological diversity, we modeled relationships between 14 forest structure variables and airborne laser scanning (ALS) data for two Italian study areas representing two common Mediterranean forests, conifer plantations and coppice oaks subjected to irregular intervals of unplanned and non-standard silvicultural interventions. The objectives were twofold: (i) to compare model prediction accuracies when using two types of ALS metrics, echo-based metrics and canopy height model (CHM)-based metrics, and (ii) to construct inferences in the form of confidence intervals for large area structural complexity parameters. Our results showed that the effects of the two study areas on accuracies were greater than the effects of the two types of ALS metrics. In particular, accuracies were less for the more complex study area in terms of species composition and forest structure. However, accuracies achieved using the echo-based metrics were only slightly greater than when using the CHM-based metrics, thus demonstrating that both options yield reliable and comparable results. Accuracies were greatest for dominant height (Hd) (R2 = 0.91; RMSE% = 8.2%) and mean height weighted by basal area (R2 = 0.83; RMSE% = 10.5%) when using the echo-based metrics, 99th percentile of the echo height distribution and interquantile distance. For the forested area, the generalized regression (GREG) estimate of mean Hd was similar to the simple random sampling (SRS) estimate, 15.5 m for GREG and 16.2 m SRS. Further, the GREG estimator with standard error of 0.10 m was considerable more precise than the SRS

  6. Comparison of ablation stake measurements and Airborne Laser Scanning results

    Science.gov (United States)

    Rieg, Lorenzo; Galos, Stephan; Klug, Christoph; Sailer, Rudolf

    2014-05-01

    Ablation measurements using ablation stakes are a well-established method in glaciology, which sees a lot of use. However, ablation stakes cannot always be installed and read at a sufficient number of points on a glacier or on multiple glaciers, due to limited personnel and financial capacities or because of inaccessible areas due to dangerous zones (crevasses, rock falls, avalanches) or remote terrain. Furthermore, ablation stakes only enable measurements of surface melt, whereas basal or internal melt processes as well as surface change related to glacier dynamics cannot be measured. Multi temporal Airborne laser scanning (ALS) can provide high resolution and very accurate topographic information for the whole glacier area, which allows the calculation of the difference in surface height and therefore - if the density profile is known or can be estimated - the determination of the local mass balance, including processes like basal melt at least to a certain degree. To gain a better understanding of the differences between ablation stake readings and differential ALS data at the stake locations, the results of both methods have been compared in detail. At Langenferner, a glacier in the Italian Eastern Alps, where mass balance measurements have been carried out since 2004, three ALS campaigns have been conducted at the end of the hydrological year in 2005, 2010 and 2013. There are about 30 ablation stakes installed at the glacier, which have been read during or very close to the time of the flight campaigns. The ablation measurements are then compared to the surface differences calculated from ALS data at the locations of the ablation stakes. To take the movement of the stakes due to glacier dyanmics into account, the position of the stakes has been measured with a differential GPS.

  7. DEVELOPMENT OF SMART PRECISION FOREST IN CONIFER PLANTATION IN JAPAN USING LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    M. Katoh

    2017-10-01

    Full Text Available Currently, the authors are planning to launch a consortium effort toward Japan’s first smart precision forestry project using laser data and to develop this technology throughout the country. Smart precision forestry information gathered using the Nagano model (laser scanning from aircraft, drone, and backpack is being developed to improve the sophistication of forest information, reduce labor-intensive work, maintain sustainable timber productivity, and facilitate supply chain management by laser sensing information in collaboration with industry, academia, and government. In this paper, we outline the research project and the technical development situation of unmanned aerial vehicle laser scanning.

  8. Development of Smart Precision Forest in Conifer Plantation in Japan Using Laser Scanning Data

    Science.gov (United States)

    Katoh, M.; Deng, S.; Takenaka, Y.; Cheung, K.; Oono, K.; Horisawa, M.; Hyyppä, J.; Yu, X.; Liang, X.; Wang, Y.

    2017-10-01

    Currently, the authors are planning to launch a consortium effort toward Japan's first smart precision forestry project using laser data and to develop this technology throughout the country. Smart precision forestry information gathered using the Nagano model (laser scanning from aircraft, drone, and backpack) is being developed to improve the sophistication of forest information, reduce labor-intensive work, maintain sustainable timber productivity, and facilitate supply chain management by laser sensing information in collaboration with industry, academia, and government. In this paper, we outline the research project and the technical development situation of unmanned aerial vehicle laser scanning.

  9. Effect of laser pulse parameters on the size and fluorescence of nanodiamonds formed upon pulsed-laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Peikang [School of Materials Science and Engineering, North University of China, Taiyuan 030051 (China); Hu, Shengliang, E-mail: hsliang@yeah.net [Key Laboratory of Instrumentation Science and Dynamic Measurement (North University of China), Ministry of Education, National Key Laboratory Science and Technology on Electronic Test and Measurement, Taiyuan 030051 (China); School of Materials Science and Engineering, North University of China, Taiyuan 030051 (China); Zhang, Taiping; Sun, Jing [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Cao, Shirui [School of Materials Science and Engineering, North University of China, Taiyuan 030051 (China)

    2010-07-15

    The size of nanodiamonds formed upon laser irradiation could be easily controlled over simply adjusting laser pulse parameters. The stable size and structure of nanodiamonds were mostly determined by laser power density and pulse width. Both large nanodiamonds with multiply twinning structure (MTS) and small nanodiamonds with single crystalline structure (SCS) emitted strong visible light after surface passivation, and their fluorescence quantum yield (QY) was 4.6% and 7.1%, respectively.

  10. Effect of laser pulse parameters on the size and fluorescence of nanodiamonds formed upon pulsed-laser irradiation

    International Nuclear Information System (INIS)

    Bai, Peikang; Hu, Shengliang; Zhang, Taiping; Sun, Jing; Cao, Shirui

    2010-01-01

    The size of nanodiamonds formed upon laser irradiation could be easily controlled over simply adjusting laser pulse parameters. The stable size and structure of nanodiamonds were mostly determined by laser power density and pulse width. Both large nanodiamonds with multiply twinning structure (MTS) and small nanodiamonds with single crystalline structure (SCS) emitted strong visible light after surface passivation, and their fluorescence quantum yield (QY) was 4.6% and 7.1%, respectively.

  11. Analytical and laser scanning techniques to determine shape properties of aggregates used in pavements

    CSIR Research Space (South Africa)

    Komba, Julius J

    2013-06-01

    Full Text Available of 19.0 mm granite aggregate particles. ................................................ 8-1 Table 8.2: Scan results of 13.2 mm granite aggregate particles. ................................................ 8-2 Table 8.3: Scan results of 9.5 mm granite... .................................................................................................................. 7-1 8 APPENDIX A: AGGREGATE SCAN RESULTS .......................................................... 8-1 9 APPENDIX B: MATLAB CODE FOR ANALYSIS OF LASER SCAN DATA ............ 9-1 10 APPENDIX C: EFFECT OF DEGREE (l) VALUE ON CONVERGENCE...

  12. Mapping metals in Parkinson's and normal brain using rapid-scanning x-ray fluorescence

    International Nuclear Information System (INIS)

    Popescu, Bogdan F Gh; George, Martin J; McCrea, Richard P E; Devon, Richard M; George, Graham N; Hanson, Akela D; Chapman, L Dean; Nichol, Helen; Bergmann, Uwe; Garachtchenko, Alex V; Luening, Katharina; Kelly, Michael E; Harder, Sheri M; Pickering, Ingrid J

    2009-01-01

    Rapid-scanning x-ray fluorescence (RS-XRF) is a synchrotron technology that maps multiple metals in tissues by employing unique hardware and software to increase scanning speed. RS-XRF was validated by mapping and quantifying iron, zinc and copper in brain slices from Parkinson's disease (PD) and unaffected subjects. Regions and structures in the brain were readily identified by their metal complement and each metal had a unique distribution. Many zinc-rich brain regions were low in iron and vice versa. The location and amount of iron in brain regions known to be affected in PD agreed with analyses using other methods. Sample preparation is simple and standard formalin-fixed autopsy slices are suitable. RS-XRF can simultaneously and non-destructively map and quantify multiple metals and holds great promise to reveal metal pathologies associated with PD and other neurodegenerative diseases as well as diseases of metal metabolism.

  13. Remote detection of nitrocompounds by laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Simeonsson, J.B.; Barnes, E.M.; Mullane, M.; Pacquette, H.L. [Univ. of Iowa, Iowa City, IA (United States)

    1995-12-31

    Localized contaminations of subsurface soil and water by nitrocompounds is an environmental problem of great concern to the Department of Defense. Pollution by these materials is problematic because of the mutagenic and carcinogenic properties of not only the parent compounds, but also their microbial degradation products. Leaching of high explosives from munitions is the primary source of this contamination as nearly all high explosives include the nitro-(NO{sub 2}-) functionality in their molecular structure. Remediation of this problem is difficult, however, as there are no techniques available for the remote detection of these compounds. Currently emphasis is on the development of fiber optic coupled sensors which can be implemented in existing cone penentrometer (CPT) systems. Photofragmentation approaches are well suited to detecting classes of molecules and have been shown to be a very effective strategy for detecting nitrocompounds, especially when the NO fragment is targeted for detection. We are investigating a photofragmentation/laser-induced fluorescence (PF/LIF) approach for the remote detection and measurement of nitrocompounds that is fully compatible with fiber optic coupling. In our studies, single wavelength excitation has been used to (i) photofragment the parent compounds and (ii) probe the resulting photofragments to detect NO. Various wavelength schemes have been evaluated. Results will be presented to demonstrate the feasibility of a PF/LIF based sensor for the remote detection of nitrocompounds.

  14. Airborne laser induced fluorescence imaging. Innovative technology summary report

    International Nuclear Information System (INIS)

    1999-06-01

    Laser-Induced Fluorescence (LIF) was demonstration as part of the Fernald Environmental Management Project (FEMP) Plant 1 Large Scale Demonstration and Deployment Project (LSDDP) sponsored by the US Department of Energy (DOE) Office of Science and Technology, Deactivation and Decommissioning Focus Area located at the Federal Energy Technology Center (FETC) in Morgantown, West Virginia. The demonstration took place on November 19, 1996. In order to allow the contaminated buildings undergoing deactivation and decommissioning (D and D) to be opened to the atmosphere, radiological surveys of floors, walls and ceilings must take place. After successful completion of the radiological clearance survey, demolition of the building can continue. Currently, this process is performed by collecting and analyzing swipe samples for radiological analysis. Two methods are used to analyze the swipe samples: hand-held frisker and laboratory analysis. For the purpose of this demonstration, the least expensive method, swipe samples analyzed by hand-held frisker, is the baseline technology. The objective of the technology demonstration was to determine if the baseline technology could be replaced using LIF

  15. The application of time decay characteristics of laser-induced fluorescence in the classification of vegetation.

    Science.gov (United States)

    Gong, Wei; Yang, Jian; Shi, Shuo; Du, Lin; Sun, Jia; Song, Shalei

    2017-02-01

    In this study, the time decay of the chlorophyll fluorescence intensity (TDCFI) of vegetation was measured based on laser-induced fluorescence (LIF) technology with a 355 nm laser serving as the excitation light source. The pseudo-color diagram of the TDCFI (PDTDCFIs) was proposed for use as a characteristic fingerprint for the analysis of various plant species based on variations in the fluorescence intensity over time. Compared with the steady-state fluorescence spectra, two-dimensional PDTDCFIs contained more spectral information, including variations in both the shape of the laser-induced fluorescence spectra and the relative intensity. The experimental results demonstrated that the PDTDCFIs of various plant species show distinct differences, and this was successfully applied in the classification of plant species. Therefore, the PDTDCFIs of plants could provide researchers with a more reliable and useful tool for the characterization of vegetation. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Periodic and uniform nanogratings formed on cemented carbide by femtosecond laser scanning

    International Nuclear Information System (INIS)

    Lian, Yunsong; Deng, Jianxin; Xing, Youqiang; Lei, Shuting; Yu, Xiaoming

    2013-01-01

    Periodic and uniform nanogratings are fabricated by femtosecond laser scanning on cemented carbide. Specifically, three experiments are designed to study the influence of single pulse energy, scanning speed, and scanning spacing on the period and the uniformity of the formed nanogratings. The results show that the sample with single pulse energy of 2 μJ, scanning speed of 1000 μm/s, and scanning spacing of 5 μm shows the best quality of nanogratings among all the tested samples at different processing parameters. The uniformity of the nanogratings is largely determined by single pulse energy, scanning speed, and scanning spacing. Single pulse energy and scanning speed significantly affect the period of the nanogratings, whereas the period of the nanogratings maintains a fixed value under different scanning spacings. The period of the nanogratings increases gradually with the decrease of the single pulse energy and the increase of the scanning speed, respectively.

  17. X-ray optics for scanning fluorescence microscopy and other applications

    International Nuclear Information System (INIS)

    Ryon, R.W.; Warburton, W.K.

    1992-05-01

    Scanning x-ray fluorescence microscopy is analogous to scanning electron microscopy. Maps of chemical element distribution are produced by scanning with a very small x-ray beam. Goal is to perform such scanning microscopy with resolution in the range of <1 to 10 μm, using standard laboratory x-ray tubes. We are investigating mirror optics in the Kirkpatrick-Baez (K-B) configuration. K-B optics uses two curved mirrors mounted orthogonally along the optical axis. The first mirror provides vertical focus, the second mirror provides horizontal focus. We have used two types of mirrors: synthetic multilayers and crystals. Multilayer mirrors are used with lower energy radiation such as Cu Kα. At higher energies such as Ag Kα, silicon wafers are used in order to increase the incidence angles and thereby the photon collection efficiency. In order to increase the surface area of multilayers which reflects x-rays at the Bragg angle, we have designed mirrors with the spacing between layers graded along the optic axis in order to compensate for the changing angle of incidence. Likewise, to achieve a large reflecting surface with silicon, the wafers are placed on a specially designed lever arm which is bent into a log spiral by applying force at one end. In this way, the same diffracting angle is maintained over the entire surface of the wafer, providing a large solid angle for photon collection

  18. Sensitive detection and separation of fluorescent derivatives using capillary electrophoresis with laser-induced fluorescence detection with 532nm Nd:YAG laser

    International Nuclear Information System (INIS)

    Vrabel, Patrik; Taborsky, Petr; Ryvolova, Marketa; Havel, Josef; Preisler, Jan

    2006-01-01

    Capillary electrophoresis with laser-induced fluorescence detection (CELIF) is a powerful tool for separation and sensitive determination of fluorescent species. Biologically active compounds, such as amino acids, peptides and proteins may exhibit native fluorescence, which is however often low and/or an expensive laser is required for excitation in UV. Therefore, labelling of the analytes with a fluorescent dye is usually necessary. In this work, a home-built CELIF instrument with diode pumped frequency-doubled continuous wave Nd:YAG excitation laser with feedback power regulation (532nm) was constructed. The suitability of this type of laser for LIF detection in a separation method was found excellent. A limit of detection (LOD) (S/N=3) of 2x10 -13 mol/l was achieved with rhodamine B, which is comparable to those obtained using similar instruments with Ar + laser [Y.F. Cheng, N.J. Dovichi, Science 242 (1988) 562, E.S. Yeung et al., J. Chromatogr. 608 (1992) 73]. LOD of a protein derivatized according to modified procedures [M.J. Little et al., Anal. Chim. Acta 339 (1997) 279, A. Chersi et al., Biochim. Biophys. Acta 1336 (1997) 83] was determined. Detection of the derivatives was found to be limited by insufficient reaction recovery at low analyte concentration, chemical noise, separation efficiency and quality of the derivatizing reagent rather than by the detector performance. As a consequence, a huge gap between the detection ability of CELIF instruments and LOD determined in real samples is revealed

  19. Retinal Oximetry with Scanning Laser Ophthalmoscope in Infants.

    Directory of Open Access Journals (Sweden)

    Wouter B Vehmeijer

    Full Text Available Dual wavelength retinal oximetry has been developed for adults, but is not available for infants. Retinal oximetry may provide insight into the pathophysiology of oxygen-mediated diseases like retinopathy of prematurity. More insight in the oxygen metabolism of the retina in infants may provide valuable clues for better understanding and subsequent prevention or treatment of the disease. The measurements of oxygen saturation are obtained with two fundus images simultaneously captured in two different wavelengths of light. The comparison in light absorption of oxygenated and deoxygenated hemoglobin can be used to estimate the oxygen saturation within the retinal vessels by means of a software algorithm. This study aims to make retinal oximetry available for neonates. The first step towards estimating retinal oxygen saturation is determining the optical density ratio. Therefore, the purpose of this study is to image healthy newborn infants with a scanning laser ophthalmoscope and determine the optical density ratio for retinal oximetry analysis.Images of the retina of full-term healthy infants were obtained with an SLO, Optomap 200Tx (Optos, with two laser wavelengths (532nm and 633nm. The infant lay face down on the lower arm of the parent, while the parent supported the chest and chin with one hand, and stabilized the back with the other hand. No mydriatics or eyelid specula were used during this study. The images were analyzed with modified Oxymap Analyzer software for calculation of the Optical Density Ratio (ODR and vessel width. The ODR is inversely and approximately linearly related to the oxygen saturation. Measurements were included from the superotemporal vessel pair. A paired t-test was used for statistical analysis.Fifty-nine infants, (58% female, were included with mean gestational age of 40 ± 1.3 weeks (mean ± SD and mean post-natal age of 16 ± 4.8 days. A total of 28 images were selected for retinal oximetry analysis. The ODR was

  20. Event-based progression detection strategies using scanning laser polarimetry images of the human retina

    NARCIS (Netherlands)

    Vermeer, K. A.; Lo, B.; Zhou, Q.; Vos, F. M.; Vossepoel, A. M.; Lemij, H. G.

    2011-01-01

    Monitoring glaucoma patients and ensuring optimal treatment requires accurate and precise detection of progression. Many glaucomatous progression detection strategies may be formulated for Scanning Laser Polarimetry (SLP) data of the local nerve fiber thickness. In this paper, several strategies,

  1. Visualization of carbon nanotubes dispersion in composite by using confocal laser scanning microscopy

    Czech Academy of Sciences Publication Activity Database

    Ilčíková, M.; Danko, M.; Doroshenko, M.; Best, A.; Mrlík, M.; Csomorová, K.; Šlouf, Miroslav; Chorvát Jr., D.; Koynov, K.; Mosnáček, J.

    2016-01-01

    Roč. 79, June (2016), s. 187-197 ISSN 0014-3057 Institutional support: RVO:61389013 Keywords : confocal laser scanning microscopy * composites * carbon nanotubes dispersion Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.531, year: 2016

  2. Exploring the functional residues in a flavin-binding fluorescent protein using deep mutational scanning.

    Directory of Open Access Journals (Sweden)

    HyeonSeok Shin

    Full Text Available Flavin mononucleotide (FMN-based fluorescent proteins are versatile reporters that can monitor various cellular processes in both aerobic and anaerobic conditions. However, the understanding of the role of individual amino acid residues on the protein function has been limited and has restricted the development of better functional variants. Here we examine the functional amino acid residues of Escherichia coli flavin mononucleotide binding fluorescent protein (EcFbFP using the application of high-throughput sequencing of functional variants, termed deep mutational scanning. The variants were classified into 329 function-retained (FR and 259 function-loss (FL mutations, and further the mutational enrichment in each amino acid residues was weighed to find the functionally important residues of EcFbFP. We show that the crucial amino acid residues of EcFbFP lie among the FMN-binding pocket, turns and loops of the protein where conformation changes occur, and spatially clustered residues near the E56-K97 salt bridges. In addition, the mutational sensitivity of the critical residues was confirmed by site-directed mutagenesis. The deep mutational scanning of EcFbFP has demonstrated important implications for constructing better functioning protein variants.

  3. [A study of a laser fluorescence device for assessing caries removal in primary teeth in vitro].

    Science.gov (United States)

    Chen, Jianghao; Qi, Man

    2011-10-01

    To explore the feasibility of using laser fluorescence device for assessing caries removal in primary teeth in vitro. 8 primary molars with approximal caries were collected, and caries were removed in vitro. The laser fluorescence readings of dentin before and after caries removal were recorded. To judge the degree of caries removal by caries detector, polarizing microscope and dental microhardness tester. The correlation of DIAGNO-dent reading with Viker's Hardness was analyzed. The feasibility of using laser fluorescence for assessing caries removal was explored. The average Viker's Hardness of dentin after caries removal with staining was (46.99 +/- 12.44) HV, and the average Viker's Hardness of normal control was (67.39 +/- 16.59) HV. There was significant difference between the two groups (P laser fluorescence readings before and after caries removal with staining (P > 0.05). And there was significant difference between the laser fluorescence readings before and after the caries removal without staining (P caries residue in sample, no matter stain or not. The laser fluorescence could not distinguish stained dentin from caries, and is not suitable for assessing caries removal.

  4. Laser fluorescence of dentin caries covered with a novel nano-filled sealant.

    Science.gov (United States)

    Braun, Andreas; Beisel, Christian; Brede, Olivier; Krause, Felix

    2013-01-01

    The aim of the present study was to assess the possibility to measure caries-induced laser fluorescence underneath a novel nano-filled fissure sealant. Sixty freshly extracted human teeth with occlusal dentine carious lesions were horizontally divided, exposing the respective lesion. Teeth were randomly assigned to three groups: (I) white fissure sealant with filler particles (Fissurit F, Voco), (II) clear fissure sealant without filler particles (Fissurit, Voco) and (III) novel experimental fissure sealant with nano-filler particles (Voco). Starting with a sealant thickness of 3 mm, laser fluorescence measurements (DIAGNOdent, KaVo) were performed after finishing the sealant surfaces with polishing papers, reducing the material at intervals of 0.5 mm until the sealant was removed completely. Evaluating a thickness of 0.5 mm, both the clear (83 % of the baseline fluorescence after fine grit polishing) and the white sealant (25 %) did not allow to measure baseline fluorescence (p 0.05). With increasing sealer thickness, fluorescence was influenced even by the experimental material (89 % of the baseline value at 1 mm). However, by using the experimental material, statistically significant higher fluorescence values than those for the other materials under study (p laser fluorescence in all groups (p laser fluorescence measurements for caries detection can be performed through thicker sealant layers compared to conventional sealant materials. Thus, it might be possible to use this material to assess a caries progression underneath the sealant and administer an appropriate therapy in due time.

  5. Laser induced fluorescence measurements of the mixing of fuel oil with air

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, A.; Bombach, R.; Hubschmid, W.; Kaeppeli, B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    We report on measurements of the mixing of fuel oil with air at atmospheric pressure in an industrial premixed gas turbine burner. The concentration of the vaporized fuel oil was measured with laser induced fluorescence. We reason that the fuel oil concentration can be considered with good accuracy as proportional to the fluorescence intensity. (author) 6 fig., 3 refs.

  6. Fabrication of fluorescent nanoparticles of dendronized perylenediimide by laser ablation in water

    NARCIS (Netherlands)

    Yasukuni, R.; Asahi, T.; Sugiyama, T.; Masuhara, H.; Sliwa, M.; Hofkens, J.; De Schryver, F. C.; Van der Auweraer, M.; Herrmann, A.; Mueller, K.; Müllen, K.

    2008-01-01

    Highly fluorescent organic nanoparticles with size of about 300 nm were prepared by nanosecond laser ablation of micrometer-sized powder of dendronized perylenediimide dispersed in water. The nanoparticle colloidal solution provided a fluorescence quantum yield of 0.58. The absorption and emission

  7. Facial recognition and laser surface scan: a pilot study

    DEFF Research Database (Denmark)

    Lynnerup, Niels; Clausen, Maja-Lisa; Kristoffersen, Agnethe May

    2009-01-01

    that the discriminatory value was 86.7%. We also tested the surface scanner in terms of reliability in establishing point measures on skulls, and compared with physical measurements performed by calipers. The variation was on average 1 mm for five cranial measures. We suggest how surface scanning might be applied...... software (MIMICS and Photoshop) the surface scans were matched with the photographs in blind trials. The matches were graded as: a good fit; possible fit; and no fit. All the surface scans and photos were matched correctly, although one surface scan could be matched with two angled photographs, meaning...

  8. In vivo study of the human skin by the method of laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Borisova, E.; Avramov, L.

    2000-01-01

    The goals of this study are to perform a preliminary evaluation of the diagnostic potential of noninvasive laser-induced auto-fluorescence spectroscopy (LIAFS) for human skin and optimize of detection and diagnosis of hollow organs and skin. In recent years, there has been growing interest in the use of laser-induced fluorescence to discriminate disease from normal surrounding tissue. The most fluorescence studies have used exogenous fluorophores of this discrimination. The laser-induced auto-fluorescence which is used for diagnosis of tissues in the human body avoids administration of any drugs. In this study a technique for optical biopsy of in vivo human skin is presented. The auto-fluorescence characterization of tissue relies on different spectral properties of tissues. It was demonstrated a differentiation between normal skin and skin with vitiligo. Two main endogenous fluorophores in the human skin account for most of the cellular auto-fluorescence for excitation wavelength 337 nm reduced from of nicotinamide adenine dinucleotide and collagen. The auto-fluorescence spectrum of human skin depend on main internal absorbers which are blood and melanin. In this study was described the effect caused by blood and melanin content on the shape of the auto-fluorescence spectrum of human skin. Human skin fluorescence spectrum might provide dermatologists with important information and such investigations are successfully used now in skin disease diagnostics, in investigation of the environmental factor impact or for evaluation of treatment efficiency. (authors)

  9. An improved three-dimensional non-scanning laser imaging system based on digital micromirror device

    Science.gov (United States)

    Xia, Wenze; Han, Shaokun; Lei, Jieyu; Zhai, Yu; Timofeev, Alexander N.

    2018-01-01

    Nowadays, there are two main methods to realize three-dimensional non-scanning laser imaging detection, which are detection method based on APD and detection method based on Streak Tube. However, the detection method based on APD possesses some disadvantages, such as small number of pixels, big pixel interval and complex supporting circuit. The detection method based on Streak Tube possesses some disadvantages, such as big volume, bad reliability and high cost. In order to resolve the above questions, this paper proposes an improved three-dimensional non-scanning laser imaging system based on Digital Micromirror Device. In this imaging system, accurate control of laser beams and compact design of imaging structure are realized by several quarter-wave plates and a polarizing beam splitter. The remapping fiber optics is used to sample the image plane of receiving optical lens, and transform the image into line light resource, which can realize the non-scanning imaging principle. The Digital Micromirror Device is used to convert laser pulses from temporal domain to spatial domain. The CCD with strong sensitivity is used to detect the final reflected laser pulses. In this paper, we also use an algorithm which is used to simulate this improved laser imaging system. In the last, the simulated imaging experiment demonstrates that this improved laser imaging system can realize three-dimensional non-scanning laser imaging detection.

  10. Application of Mobile Laser Scanning for Lean and Rapid Highway Maintenance and Construction

    Science.gov (United States)

    2015-08-28

    Mobile Terrestrial Laser Scanning (MTLS) is an emerging technology that combines the use of a laser scanner(s), the Global Navigation Satellite System (GNSS), and an Inertial Measurement Unit (IMU) on a vehicle to collect geo-spatial data. The overal...

  11. Non-scanning x-ray fluorescence microscope: application to real time micro-imaging

    International Nuclear Information System (INIS)

    Sakurai, K.; Eba, H.

    2000-01-01

    So far, x-ray fluorescence (XRF) micro-imaging has been performed by a 2D positional scan of a sample against a collimated beam. Obtaining information on specific elements in a nondestructive manner is an attractive prospect for many scientific applications. Furthermore, a synchrotron micro-beam can enhance the spatial resolution down to 0.1 μm. However, the total measuring time becomes quite long (a few hours to a half day), since one needs a number of scanning points in order to obtain a high-quality image. It is possible to obtain an x-ray image with 1 M pixels and with 20 μm resolution in a very short time of 20 sec - 3 min using a non-scanning XRF microscope, which is based on completely different concept. In the present report, we discuss the application of this technique to real time micro-imaging. The experiments were carried out at BL-4A, Photon Factory, Tsukuba, Japan. We employed a grazing-incidence arrangement to make primary x-rays illuminate the whole sample surface. We adopted parallel-beam optics and extremely-close-geometry in order to detect x-ray fluorescence with a CCD camera. The selective-excitation capability of tunable monochromatic synchrotron radiation is a feasible method for distinguishing the elements of interest. One can obtain an image of each element by differentiating the images obtained above and below the absorption edges of interest. The growth of metallic dendrites from a solution dropped on a substrate was studied successfully. Several different growth patterns, corresponding to concentration and other conditions for diffusion, were observed as x-ray images. Since the present technique requires only 40 sec for each shot, it is possible to record a growing process through repeated exposures like a movie. The authors would like to thank Prof. A. Iida (Photon Factory) for his valuable comments. (author)

  12. Laser scanning confocal microscopy and laser tweezers based experiments to understand dentine-bacteria interactions

    Science.gov (United States)

    Peng, Sum Chee; Mohanty, Samarendra; Gupta, P. K.; Kishen, Anil

    2007-02-01

    Failure of endodontic treatment is commonly due to Enterococcal infection. In this study influence of chemical treatments of type-I collagen membrane by chemical agents commonly used in endodontic treatment on Enterococcus faecalis cell adherence was evaluated. In order to determine the change in number of adhering bacteria after chemical treatment, confocal laser scanning microscopy was used. For this, overnight culture of E faecalis in All Culture broth was applied to chemically treated type-I collagen membrane. It was found that Ca(OH) II treated groups had statistically significant (p value=0.05) increase in population of bacteria adherence. The change in adhesion force between bacteria and collagen was determined by using optical tweezers (1064 nm). For this experiment, Type-I collagen membrane was soaked for 5 mins in a media that contained 50% all culture media and 50% saturated Ca(OH) II . The membrane was spread on the coverslip, on which diluted bacterial suspension was added. The force of laser tweezers on the bacteria was estimated at different trap power levels using viscous drag method and trapping stiffness was calculated using Equipartition theorem method. Presence of Ca(OH) II was found to increase the cell-substrate adherence force from 0.38pN to >2.1pN. Together, these experiments show that it was highly probable that the increase in adherence to collagen was due to a stronger adhesion in the presence of Ca (OH) II.

  13. High-Throughput Analysis With 96-Capillary Array Electrophoresis and Integrated Sample Preparation for DNA Sequencing Based on Laser Induced Fluorescence Detection

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Gang [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    The purpose of this research was to improve the fluorescence detection for the multiplexed capillary array electrophoresis, extend its use beyond the genomic analysis, and to develop an integrated micro-sample preparation system for high-throughput DNA sequencing. The authors first demonstrated multiplexed capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) separations in a 96-capillary array system with laser-induced fluorescence detection. Migration times of four kinds of fluoresceins and six polyaromatic hydrocarbons (PAHs) are normalized to one of the capillaries using two internal standards. The relative standard deviations (RSD) after normalization are 0.6-1.4% for the fluoresceins and 0.1-1.5% for the PAHs. Quantitative calibration of the separations based on peak areas is also performed, again with substantial improvement over the raw data. This opens up the possibility of performing massively parallel separations for high-throughput chemical analysis for process monitoring, combinatorial synthesis, and clinical diagnosis. The authors further improved the fluorescence detection by step laser scanning. A computer-controlled galvanometer scanner is adapted for scanning a focused laser beam across a 96-capillary array for laser-induced fluorescence detection. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries. The limit of detection for fluorescein is 3 x 10-11 M (S/N = 3) for 5-mW of total laser power scanned at 4 Hz. The observed cross-talk among capillaries is 0.2%. Advantages include the efficient utilization of light due to the high duty-cycle of step scan, good detection performance due to the reduction of stray light, ruggedness due to the small mass of the galvanometer mirror, low cost due to the simplicity of components, and flexibility due to the independent paths for excitation and emission.

  14. Determination of the thickness and structure of the skin barrier by in vivo laser scanning microscopy

    International Nuclear Information System (INIS)

    Lademann, J; Richter, H; Patzelt, A; Knorr, F; Sterry, W; Astner, S; Antoniou, Ch

    2008-01-01

    Normal skin barrier function is an essential aspect of skin homeostasis and regeneration. Dynamic inflammatory, proliferative and neoplastic skin processes such as wound healing, psoriasis and contact dermatitis are associated with a significant disruption of the skin barrier. In recent years, there has been increasing interest in evaluating cosmetic and pharmacologic products for their ability to restore these protective properties. The gold standard for characterization of barrier function has been the measurement of the transepidermal water loss, however the disadvantage of this method is its interference with several endogenous and exogenous factors such as hydration, perspiration and topically applied substances. This study was aimed to test the clinical applicability of a fluorescence confocal laser scanning microscope (LSM) for a systematic morphologic analysis of the structure, integrity and thickness of the stratum corneum in 10 otherwise healthy volunteers. The influence of skin treatment with commercial moisturizing cream on skin barrier function was evaluated in serial non-invasive examinations. Our findings showed that in vivo LSM may represent a simple and efficient method for the characterization of skin barrier properties, such as the thickness and hydration of the stratum corneum

  15. Laser line scan underwater imaging by complementary metal-oxide-semiconductor camera

    Science.gov (United States)

    He, Zhiyi; Luo, Meixing; Song, Xiyu; Wang, Dundong; He, Ning

    2017-12-01

    This work employs the complementary metal-oxide-semiconductor (CMOS) camera to acquire images in a scanning manner for laser line scan (LLS) underwater imaging to alleviate backscatter impact of seawater. Two operating features of the CMOS camera, namely the region of interest (ROI) and rolling shutter, can be utilized to perform image scan without the difficulty of translating the receiver above the target as the traditional LLS imaging systems have. By the dynamically reconfigurable ROI of an industrial CMOS camera, we evenly divided the image into five subareas along the pixel rows and then scanned them by changing the ROI region automatically under the synchronous illumination by the fun beams of the lasers. Another scanning method was explored by the rolling shutter operation of the CMOS camera. The fun beam lasers were turned on/off to illuminate the narrow zones on the target in a good correspondence to the exposure lines during the rolling procedure of the camera's electronic shutter. The frame synchronization between the image scan and the laser beam sweep may be achieved by either the strobe lighting output pulse or the external triggering pulse of the industrial camera. Comparison between the scanning and nonscanning images shows that contrast of the underwater image can be improved by our LLS imaging techniques, with higher stability and feasibility than the mechanically controlled scanning method.

  16. RAYSAW: a log sawing simulator for 3D laser-scanned hardwood logs

    Science.gov (United States)

    R. Edward. Thomas

    2013-01-01

    Laser scanning of hardwood logs provides detailed high-resolution imagery of log surfaces. Characteristics such as sweep, taper, and crook, as well as most surface defects, are visible to the eye in the scan data. In addition, models have been developed that predict interior knot size and position based on external defect information. Computerized processing of...

  17. Benchmarking Naval Shipbuilding With 3D Laser Scanning, Additive Manufacturing, and Collaborative Product Lifecycle Management

    Science.gov (United States)

    2016-04-30

    laser scanning services were used for shipcheck of a three-story hangar bay on the USS Abraham Lincoln (CVN 72). Scanning the HVAC , piping, fuel...referred to as 3D printing. In the automotive industry, Ford Motor Co. uses 3D printing in several areas, including the tooling used to create production

  18. Characterization of the stem anatomy of the Eocene fern Dennstaedtiopsis aerenchymata (Dennstaedtiaceae) by use of confocal laser scanning microscopy.

    Science.gov (United States)

    Shi, Chris S; Schopf, J William; Kudryavtsev, Anatoliy B

    2013-08-01

    Permineralization provides the most faithful known mode of three-dimensional preservation of the morphology and cellular anatomy of fossil plants. Standard optical microscopic documentation of such structures can provide only an approximation of their true three-dimensional form and is incapable of revealing fine-structural (<300 nm) details, deficiencies that can be addressed by the use of confocal laser scanning microscopy (CLSM). To demonstrate the usefulness of CLSM in such studies, we compare confocal laser scanning micrographs and optical photomicrographs of the permineralized tissues of rhizomes and petioles of the Eocene fern Dennstaedtiopsis aerenchymata preserved in cherts of the Clarno Formation of Oregon, USA, and the Allenby Formation (Princeton chert) of British Columbia, Canada. The laser-induced fluorescence detected by CLSM produces crisp high-resolution images of the three-dimensionally permineralized tissues of Dennstaedtiopsis aerenchymata. Tissues analyzed include the epidermis and epidermal hairs, cortex, aerenchyma, endodermis, vascular tissue, and pith-for each of which, CLSM yields results superior to those of standard optical microscopy. CLSM and previous Raman spectroscopic analyses of the same specimens provide evidence consistent with original biochemistry. Use of CLSM to characterize the morphology and cellular anatomy of permineralized fossil plants can provide accurate data in two and three dimensions at high spatial resolution, information that can be critically important to taxonomic, taphonomic, and developmental interpretations. Results presented here from this first detailed CLSM-based study of permineralized plant axes indicate that this nonintrusive, nondestructive technique should be widely applicable in paleobotany.

  19. A NEW APPROACH FOR SEGMENTATION-BASED TEXTURING OF LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    Z. Lari

    2015-02-01

    Full Text Available In recent years, laser scanning systems have been recognized as a fast and accurate technology for the acquisition of high density spatial data. The advent of these systems has reduced the cost and increased the availability of accurate 3D data for mapping, modelling, and monitoring applications. The original laser scanning data does not explicitly provide meaningful information about the characteristics of the scanned surfaces. Therefore, reliable processing procedures are applied for information extraction from these datasets. However, the derived surfaces through laser scanning data processing cannot be effectively interpreted due to the lack of spectral information. To resolve this problem, a new texturing procedure is introduced in this paper to improve the interpretability of laser scanning-derived surfaces using spectral information from overlapping imagery. In this texturing approach, individual planar regions, derived through a laser scanning data segmentation procedure, are textured using the available imagery. This texturing approach, which aims to overcome the computational inefficiency of the previously-developed point-based texturing techniques, is implemented in three steps. In the first step, the visibility of the segmented planar regions in the available imagery is checked and a list of appropriate images for texturing each planar region is established. An occlusion detection procedure is then performed to identify the parts of the segmented regions which are occluding/being occluded by other regions in the field of view of the utilized images. In the second step, visible parts of planar regions are decomposed into parts which should be textured using individual images. Finally, a rendering procedure is performed to texture these parts using available images. Experimental results from real laser scanning dataset and overlapping imagery demonstrate the feasibility of the proposed approach for texturing laser scanning

  20. Two-dimensional fluorescence spectroscopy of uranium isotopes in femtosecond laser ablation plumes

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Mark C.; Brumfield, Brian E.; LaHaye, Nicole L.; Harilal, Sivanandan S.; Hartig, Kyle C.; Jovanovic, Igor

    2017-06-19

    We demonstrate measurement of uranium isotopes in femtosecond laser ablation plumes using two-dimensional fluorescence spectroscopy (2DFS). The high-resolution, tunable CW-laser spectroscopy technique clearly distinguishes atomic absorption from 235U and 238U in natural and highly enriched uranium metal samples. We present analysis of spectral resolution and analytical performance of 2DFS as a function of ambient pressure. Simultaneous measurement using time-resolved absorption spectroscopy provides information on temporal dynamics of the laser ablation plume and saturation behavior of fluorescence signals. The rapid, non-contact measurement is promising for in-field, standoff measurements of uranium enrichment for nuclear safety and security applications.

  1. Two-laser induced selective infrared-visible fluorescence for thin film analysis

    International Nuclear Information System (INIS)

    Richardson, J.H.; Dering, J.P.; Johnson, D.C.; Hrubesh, L.W.

    1980-01-01

    A laser technique has been developed to enhance its sensitivity for thin film analysis of mixtures. A c-w visible or uv laser was used to stimulate visible fluorescence from a thin fluorophor film, and a chopped low-power infrared laser was used to selectively excite characteristic infrared absorption bands in the sample. The resulting modulated visible fluorescence signal was monitored by an optical detection system. The technqiue has been applied to the quantitative determination of mixtures of coumarin 7, rubene, and rhodamine 6G; however, quantitative analysis has been impossible due to the difficulty in obtaining a uniform thin film

  2. Manipulation of cellular light from green fluorescent protein by a femtosecond laser

    Science.gov (United States)

    He, Hao; Li, Shiyang; Wang, Shaoyang; Hu, Minglie; Cao, Youjia; Wang, Chingyue

    2012-10-01

    Green fluorescent protein (GFP) is one of the most widely studied and exploited proteins in biochemistry and cell biology. It emits fluorescence following optical excitation, which is usually provided by a laser. Here, we report that fluorescence from enhanced GFP can be `turned off' by exposing cells to laser light. A short flash of femtosecond laser light is shown to deplete calcium in the endoplasmic reticulum of cells. Calcium-release-activated calcium channels are then activated by stromal interaction molecule 1 (STIM1). The rise in intracellular Ca2+ depolarizes mitochondria and increases the leakage of reactive oxygen species, which then permanently bleach the GFP. This controllable optical scheme for reactive oxygen species generation can also be used to modulate the photoconversion of GFP fluorescence from green to red emission and provide a mechanism for influencing cellular molecular dynamics.

  3. Influence of dental materials used for sealing caries lesions on laser fluorescence measurements.

    Science.gov (United States)

    Celiberti, Paula; Carvalho, Thiago S; Raggio, Daniela P; Mendes, Fausto M

    2012-03-01

    The aim of this study was to determine the influence of thickness and aging on the intrinsic fluorescence of sealing materials and their ability to block fluorescence from the underlying surface as assessed using a laser fluorescence device. Cavities of 0.5 mm and 1 mm depth were drilled into acrylic boards which were placed over two surfaces with different fluorescence properties: a low-fluorescence surface, to assess the intrinsic fluorescence of the sealing materials, and a high-fluorescence surface, to assess the fluorescence-blocking ability of the sealing materials. Ten cavities of each depth were filled with different sealing materials: Adper Scotchbond Multi-Purpose, Adper Single Bond 2, FluroShield, Conseal f and UltraSeal XT Plus. Fluorescence was measured with a DIAGNOdent pen at five different time points: empty cavity, after polymerization, and 1 day, 1 week and 1 month after filling. The individual values after polymerization, as well as the area under the curve for the different periods were submitted to ANOVA and the Tukey test (p caries by laser fluorescence.

  4. Accelerated noncontact laser ultrasonic scanning for damage detection using combined binary search and compressed sensing

    Science.gov (United States)

    Park, Byeongjin; Sohn, Hoon; Liu, Peipei

    2017-08-01

    Laser ultrasonic scanning is attractive for damage detection due to its noncontact nature, sensitivity to local damage, and high spatial resolution. However, its practicality is limited because scanning at a high spatial resolution demands a prohibitively long scanning time. Inspired by binary search and compressed sensing, an accelerated laser scanning technique is developed to localize and visualize damage with reduced scanning points and scanning time. First, the approximate damage location is identified by examining the interactions between the ultrasonic waves and damage at the sparse scanning points that are selected by the binary search algorithm. Here, a time-domain laser ultrasonic response is transformed into a spatial ultrasonic domain using a basis pursuit approach so that the interactions between the ultrasonic waves and damage, such as reflections and transmissions, can be better identified in the spatial ultrasonic domain. Second, wavefield images around the damage are reconstructed from the previously selected scanning points using compressed sensing. The performance of the proposed accelerated laser scanning technique is validated using a numerical simulation performed on an aluminum plate with a notch and experiments performed on an aluminum plate with a crack and a carbon fiber-reinforced plastic plate with delamination. The number of scanning points that is necessary for damage localization and visualization is dramatically reduced from N · M to 2log2 N ·log2 M . N and M represent the number of equally spaced scanning points in the x and y directions, respectively, which are required to obtain full-field wave propagation images of the target inspection region. For example, the number of scanning points in the composite plate experiment is reduced by 97.1% (from 2601 points to 75 points).

  5. Assessment of DNA replication in central nervous system by Laser Scanning Cytometry

    Science.gov (United States)

    Lenz, Dominik; Mosch, Birgit; Bocsi, Jozsef; Arendt, Thomas; Tárnok, Attila

    2004-07-01

    μIn neurons of patients with Alzheimers's disease (AD) signs of cell cycle re-entry as well as polyploidy have been reported1, 2, indicating that the entire or a part of the genome of the neurons is duplicated before its death but mitosis is not initiated so that the cellular DNA content remains tetraploid. It was concluded, that this imbalance is the direct cause of the neuronal loss in AD3. Manual counting of polyploidal cells is possible but time consuming and possibly statistically insufficient. The aim of this study was to develop an automated method that detects the neuronal DNA content abnormalities with Laser Scanning Cytometry (LSC).Frozen sections of formalin-fixed brain tissue of AD patients and control subjects were labelled with anti-cyclin B and anti-NeuN antibodies. Immunolabelling was performed using Cy5- and Cy2-conjugated secondary antibodies and biotin streptavidin or tyramid signal amplification. In the end sections of 20m thickness were incubated with propidium iodide (PI) (50μg/ml) and covered on slides. For analysis by the LSC PI was used as trigger. Cells identified as neurons by NeuN expression were analyzed for cyclin B expression. Per specimen data of at least 10,000 neurons were acquired. In the frozen brain sections an automated quantification of the amount of nuclear DNA is possible with LSC. The DNA ploidy as well as the cell cycle distribution can be analyzed. A high number of neurons can be scanned and the duration of measuring is shorter than a manual examination. The amount of DNA is sufficiently represented by the PI fluorescence to be able to distinguish between eu- and polyploid neurons.

  6. Development of Laser-Induced Fluorescence Diagnostic for the Paul Trap Simulator Experiment

    CERN Document Server

    Chung, Moses; Efthimion, Philip; Gilson, Erik P; Majeski, Richard; Startsev, Edward

    2005-01-01

    The Paul Trap Simulator Experiment (PTSX) is a cylindrical Paul trap whose purpose is to simulate the nonlinear dynamics of intense charged particle beam propagation in alternating-gradient magnetic transport systems. For the in-situ measurement of the transverse ion density profile in the PTSX device, which is essential for the study of beam mismatch and halo particle production, a laser-induced fluorescence diagnostic system is being developed. Instead of cesium, which has been used in the initial phase of the PTSX experiment, barium has been selected as the preferred ion for the laser-induced fluorescence diagnostic. The installation of the barium ion source and the characterization of the tunable dye laser system are discussed. The design of the collection optics with an intensified CCD camera system is also discussed. Finally, initial test results using the laser-induced fluorescence diagnostic will be presented.

  7. Ultratrace determination of lead in whole blood using electrothermal atomization laser-excited atomic fluorescence spectrometry.

    Science.gov (United States)

    Wagner, E P; Smith, B W; Winefordner, J D

    1996-09-15

    Laser-excited atomic fluorescence has been used to detect lead that was electrothermally atomized from whole blood in a graphite furnace. A 9 kHz repetition rate copper vapor laser pumped dye laser was used to excite the lead at 283.3 nm, and the resulting atomic fluorescence was detected at 405.8 nm. No matrix modification was used other than a 1:21 dilution of the whole blood with high-purity water. Using the atomic fluorescence peak area as the analytical measure and a background correction technique based upon a simultaneous measurement of the transmitted laser intensity, excellent agreement for NIST and CDC certified whole blood reference samples was obtained with aqueous standards. A limit of detection in blood of 10 fg/mL (100 ag absolute) was achieved.

  8. Three-dimensional laser scanning technique to quantify aggregate and ballast shape properties

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2013-06-01

    Full Text Available using the “Properties Tree” tool in the software. The software allows users to merge scans for increased quality, change the shape around curved surfaces, sharpen edges, extend shapes, add thicknesses and perform Boolean operations on polygon surfaces......VVVVV   321 1 (5) In the 3-D laser scanning system, the surface area of a particle is determined using triangulation method from the matrix of mesh points of triangular elements. The laser scanning software divides the surface mesh of modelled aggregate...

  9. 3D Laser Scanning Assisted by Ordinary Plane Mirror for Non-direct Viewing Area

    Directory of Open Access Journals (Sweden)

    ZHANG Fan

    2017-12-01

    Full Text Available Terrestrial 3D laser scanning is one of principal methods to get the geometric information of object surface,and the integrity of the scanned object is a basic requirement in data acquisition. In order to solve the missing point cloud problem due to the scanning dead angle caused by confined working space,this paper proposes a method using ordinary plane mirror to obtain laser scanning data for non-direct viewing area according to the plane mirror reflection principle,analyzes the influence mechanism of the ordinary plane mirror on the propagation path and distance of laser beam,deduces the coordinate equation of the object point corresponding to the image point reflected by ordinary plane mirror in laser scanning. Given the laser scanning characteristic,this paper introduces a mirror reflection system included target balls and ordinary plane mirror,and expounds the system construction,system calibration and constructing method of system coordinate system. The feasibility and precision of the method are verified by experiments.

  10. Dual-wavelength external cavity laser device for fluorescence suppression in Raman spectroscopy

    Science.gov (United States)

    Zhang, Xuting; Cai, Zhijian; Wu, Jianhong

    2017-10-01

    Raman spectroscopy has been widely used in the detection of drugs, pesticides, explosives, food additives and environmental pollutants, for its characteristics of fast measurement, easy sample preparation, and molecular structure analyzing capability. However, fluorescence disturbance brings a big trouble to these applications, with strong fluorescence background covering up the weak Raman signals. Recently shifted excitation Raman difference spectroscopy (SERDS) not only can completely remove the fluorescence background, but also can be easily integrated into portable Raman spectrometers. Usually, SERDS uses two lasers with small wavelength gap to excite the sample, then acquires two spectra, and subtracts one to the other to get the difference spectrum, where the fluorescence background will be rejected. So, one key aspects of successfully applying SERDS method is to obtain a dual-wavelength laser source. In this paper, a dual-wavelength laser device design based on the principles of external cavity diode laser (ECDL) is proposed, which is low-cost and compact. In addition, it has good mechanical stability because of no moving parts. These features make it an ideal laser source for SERDS technique. The experiment results showed that the device can emit narrow-spectral-width lasers of two wavelengths, with the gap smaller than 2 nanometers. The laser power corresponding to each wavelength can be up to 100mW.

  11. Tumor angiogenesis assessment using multi-fluorescent scans on murine slices by Markov random field framework

    Science.gov (United States)

    Laifa, Oumeima; Le Guillou-Buffello, Delphine; Racoceanu, Daniel

    2017-11-01

    The fundamental role of vascular supply in tumor growth makes the evaluation of the angiogenesis crucial in assessing effect of anti-angiogenic therapies. Since many years, such therapies are designed to inhibit the vascular endothelial growth factor (VEGF). To contribute to the assessment of anti-angiogenic agent (Pazopanib) effect on vascular and cellular structures, we acquired data from tumors extracted from a murine tumor model using Multi- Fluorescence Scanning. In this paper, we implemented an unsupervised algorithm combining the Watershed segmentation and Markov Random Field model (MRF). This algorithm allowed us to quantify the proportion of apoptotic endothelial cells and to generate maps according to cell density. Stronger association between apoptosis and endothelial cells was revealed in the tumors receiving anti-angiogenic therapy (n = 4) as compared to those receiving placebo (n = 4). A high percentage of apoptotic cells in the tumor area are endothelial. Lower density cells were detected in tumor slices presenting higher apoptotic endothelial areas.

  12. Investigation of Nematode Diversity using Scanning Electron Microscopy and Fluorescent Microscopy

    Science.gov (United States)

    Seacor, Taylor; Howell, Carina

    2013-03-01

    Nematode worms account for the vast majority of the animals in the biosphere. They are colossally important to global public health as parasites, and to agriculture both as pests and as beneficial inhabitants of healthy soil. Amphid neurons are the anterior chemosensory neurons in nematodes, mediating critical behaviors including chemotaxis and mating. We are examining the cellular morphology and external anatomy of amphid neurons, using fluorescence microscopy and scanning electron microscopy, respectively, of a wide range of soil nematodes isolated in the wild. We use both classical systematics (e.g. diagnostic keys) and molecular markers (e.g. ribosomal RNA) to classify these wild isolates. Our ultimate aim is to build a detailed anatomical database in order to dissect genetic pathways of neuronal development and function across phylogeny and ecology. Research supported by NSF grants 092304, 0806660, 1058829 and Lock Haven University FPDC grants

  13. Correlation of a scanning laser derived oedema index and visual function following grid laser treatment for diabetic macular oedema.

    Science.gov (United States)

    Hudson, C; Flanagan, J G; Turner, G S; Chen, H C; Young, L B; McLeod, D

    2003-04-01

    To correlate change of an oedema index derived by scanning laser tomography with change of visual function in patients undergoing grid laser photocoagulation for clinically significant diabetic macular oedema (DMO). The sample comprised 24 diabetic patients with retinal thickening within 500 micro m of the fovea. Inclusion criteria included a logMAR visual acuity of 0.25, or better. Patients were assessed twice before a single session of grid laser treatment and within 1 week of, and at 1, 2, 4, and 12 weeks after, treatment. At each visit, patients underwent logMAR visual acuity, conventional and short wavelength automated perimetry (SWAP), and scanning laser tomography. Each visual function parameter was correlated with the mean oedema index. The mean oedema index represented the z-profile signal width divided by the maximum reflectance intensity (arbitrary units). A Pearson correlation coefficient (Bonferroni corrected) was undertaken on the data set of each patient. 13 patients exhibited significant correlation of the mean oedema index and at least one measure of visual function for the 10 degrees x 10 degrees scan field while 10 patients correlated for the 20 degrees x 20 degrees scan field. Seven patients demonstrated correlation for both scan fields. Laser photocoagulation typically resulted in an immediate loss of perimetric sensitivity whereas the oedema index changed over a period of weeks. Localised oedema did not impact upon visual acuity or letter contrast sensitivity when situated extrafoveally. Correlation of change of the oedema index and of visual function following grid laser photocoagulation was not found in all patients. An absence of correlation can be explained by the localised distribution of DMO in this sample of patients, as well as by differences in the time course of change of the oedema index and visual function. The study has objectively documented change in the magnitude and distribution of DMO following grid laser treatment and has

  14. Laser diagnostics in combustion. Elastic scattering and picosecond laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Ossler, Frederik

    1999-05-01

    Elastic scattering and the Lorenz-Mie (LM) theory in particular is used for the characterization of sub-micron- and micron-sized droplets of organic fuels in sprays and aerosols. Calculations on the Lorenz-Mie theory show that backward-sideward scattered visible radiation can be used for unambiguous detection of ensembles of homogeneous droplets of organic substances with diameters around 1 micrometer (size parameter between 2 and 6). A backward feature in the polarization ratio appears with a value considerably higher than one, on the opposite to the case of the rainbow observed for larger droplets. A comparison between measurements and LM calculations showed that a large amount of droplets in aerosols and well-atomized sprays were smaller than one micrometer in diameter. The LM theory was also used to characterize different size groups in a burning spray. A 3 - D technique based on a picosecond laser and a streak camera was demonstrated for measurements of fast and turbulent biphase flows. The entire 3 - D information was obtained within a time-span of less than 15 nanoseconds. A 2 - D technique for lifetime measurements based on a picosecond laser and a streak camera has been demonstrated on static objects. An analysis indicates that the technique may be applied to measurements of lifetimes around or below one picosecond employing femtosecond lasers and femtosecond streak-cameras. The technique may in principle be used to study dynamic systems when two detectors are used. Fluorescence lifetime measurements on hydrogen and oxygen atoms in flames at atmospheric pressure demonstrate the need of lasers with suiting spectral properties such as jitter and linewidth and the need of detectors with high sensitivity in the near IR in the case of oxygen atoms. The fluorescence lifetimes of gas phase acetone and 3-pentanone at 266 nm excitation wavelength have been measured for mixtures with nitrogen and air at temperatures between 323 and 723 K and pressures between 0

  15. A vision-based system for fast and accurate laser scanning in robot-assisted phonomicrosurgery.

    Science.gov (United States)

    Dagnino, Giulio; Mattos, Leonardo S; Caldwell, Darwin G

    2015-02-01

    Surgical quality in phonomicrosurgery can be improved by open-loop laser control (e.g., high-speed scanning capabilities) with a robust and accurate closed-loop visual servoing systems. A new vision-based system for laser scanning control during robot-assisted phonomicrosurgery was developed and tested. Laser scanning was accomplished with a dual control strategy, which adds a vision-based trajectory correction phase to a fast open-loop laser controller. The system is designed to eliminate open-loop aiming errors caused by system calibration limitations and by the unpredictable topology of real targets. Evaluation of the new system was performed using CO(2) laser cutting trials on artificial targets and ex-vivo tissue. This system produced accuracy values corresponding to pixel resolution even when smoke created by the laser-target interaction clutters the camera view. In realistic test scenarios, trajectory following RMS errors were reduced by almost 80 % with respect to open-loop system performances, reaching mean error values around 30 μ m and maximum observed errors in the order of 60 μ m. A new vision-based laser microsurgical control system was shown to be effective and promising with significant positive potential impact on the safety and quality of laser microsurgeries.

  16. AN AUTOMATIC ALGORITHM FOR MINIMIZING ANOMALIES AND DISCREPANCIES IN POINT CLOUDS ACQUIRED BY LASER SCANNING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    F. Bordin

    2016-06-01

    Full Text Available Laser scanning technique from airborne and land platforms has been largely used for collecting 3D data in large volumes in the field of geosciences. Furthermore, the laser pulse intensity has been widely exploited to analyze and classify rocks and biomass, and for carbon storage estimation. In general, a laser beam is emitted, collides with targets and only a percentage of emitted beam returns according to intrinsic properties of each target. Also, due interferences and partial collisions, the laser return intensity can be incorrect, introducing serious errors in classification and/or estimation processes. To address this problem and avoid misclassification and estimation errors, we have proposed a new algorithm to correct return intensity for laser scanning sensors. Different case studies have been used to evaluate and validated proposed approach.

  17. Scanning protein analysis of electrofocusing gels using X-ray fluorescence.

    Science.gov (United States)

    Matsuyama, Satoshi; Matsunaga, Akihiro; Sakamoto, Shinichi; Iida, Yutaka; Suzuki, Yoshinari; Ishizaka, Yukihito; Yamauchi, Kazuto; Ishikawa, Tetsuya; Shimura, Mari

    2013-05-01

    Recently, "metallomics," in addition to genomics and proteomics, has become a focus as a novel approach to identify sensitive fluctuations in homeostasis that accompany metabolic processes, such as stress responses, differentiation, and proliferation. Cellular elements and associated protein behavior provide important clues for understanding cellular and disease mechanism(s). It is important to develop a system for measuring the native status of the protein. In this study, we developed an original freeze-dried electrofocusing native gel over polyimide film (native-gel film) for scanning protein analysis using synchrotron radiation excited X-ray fluorescence (SPAX). To our knowledge, this is the first report detailing the successful mapping of metal-associated proteins of electrofocusing gels using X-ray fluorescence. SPAX can provide detection sensitivity equivalent to that of LA-ICP-MS. In addition to this increased sensitivity, SPAX has the potential to be combined with other X-ray spectroscopies. Our system is useful for further applications in proteomics investigating cellular element-associated protein behaviors and disease mechanisms.

  18. Fluorescence imaging in vivo: raster scanned point-source imaging provides more accurate quantification than broad beam geometries.

    Science.gov (United States)

    Pogue, Brian W; Gibbs, Summer L; Chen, Bin; Savellano, Mark

    2004-02-01

    Two fluorescence imaging systems were compared for their ability to quantify mean fluorescence intensity from surface-weighted imaging of tissue. A broad beam CCD camera system was compared to a point sampling system that raster scans to create the image. The effects of absorption and scattering in the background tissue volume were shown to be similar in their effect upon the signal, but the effect of the three-dimensional shape of the tissue was shown to be a significant distortion upon the signal. Spherical phantoms with Intralipid and blood for absorber and scatterer were used with a fixed concentration of aluminum phthalocyanine fluorophore to illustrate that the mean intensity observed with the broad beam system increased with size, while the mean intensity observed with the raster scanned system was not as significantly affected. Similar results were observed in vivo with mice injected with the fluorophore and imaged multiple times to observe the pharmacokinetics of the drug. The fluorescence in the tumor observed with the broad beam system was higher than that observed with the raster scanned system. Based upon the phantom and animal observations in this study, it should be concluded that using broad beam fluorescence imaging systems to quantify fluorescence in vivo may be problematic when comparing tissues with different three dimensional characteristics. In particular, the ratio of fluorescence from tumor to normal tissue can yield inaccurate results when the tumor is large. However, similar measurements with a narrow beam system that is raster scanned to create the images are not as significantly affected by the three dimensional shape of the tissue. Raster scanned imaging appears to provide a more uniform and accurate way to quantify fluorescence signals from distributed tissues in vivo.

  19. scanning speed influence on the physical properties of laser metal

    African Journals Online (AJOL)

    user

    2017-01-01

    Jan 1, 2017 ... machining. The use of laser metal deposition process to produce titanium alloy parts is an excellent alternative to traditional techniques. A number of studies has appeared in the literature on LMD for the fabrication of titanium. Nigerian Journal of Technology (NIJOTECH). Vol. 36, No. 1, January 2017, pp.

  20. Structural modification of silica glass by laser scanning

    International Nuclear Information System (INIS)

    Zhao Jian; Sullivan, James; Zayac, John; Bennett, Ted D.

    2004-01-01

    The thermophysical nature of rapid CO 2 laser heating of silica glass is explored using a numerical simulation that considers the structural state of the glass, as characterized by the fictive temperature. The fictive temperature reflects the thermodynamic temperature at which the glass structure would be in equilibrium. To demonstrate that the thermophysical model can accurately predict the structural change in the glass, the fictive temperature is measured experimentally utilizing the fact that the fictive temperature change corresponds to a change of glass properties that can be revealed through wet chemical etching. The relationship between the etch rate and the fictive temperature is determined by preparing and etching samples of known fictive temperature. Wet chemical etching is used to measure the fictive temperature over the entire laser affected zone and the results are found to compare favorably with the results of the thermophysical model. The model and experimental measurements demonstrate that rapid laser processing results in an increased fictive temperature near the surface of the glass. The fictive temperature increase is about 1000 K and is uniform to within 5% over the laser affected zone. Near the boundary of this zone, the fictive temperature transitions abruptly to the value of the surrounding untreated glass

  1. Eye Exam: Is a Laser Retina Scan Worthwhile?

    Science.gov (United States)

    ... 2017. Yanoff M, et al., eds. Principles of lasers. In: Ophthalmology. 4th ed. Edinburgh, U.K.: Mosby Elsevier; 2014. https://www.clinicalkey.com. Accessed Aug. 27, 2017. Nov. 16, 2017 Original article: http://www.mayoclinic.org/healthy-lifestyle/adult-health/ ...

  2. Unsynchronized scanning with a low-cost laser range finder for real-time range imaging

    Science.gov (United States)

    Hatipoglu, Isa; Nakhmani, Arie

    2017-06-01

    Range imaging plays an essential role in many fields: 3D modeling, robotics, heritage, agriculture, forestry, reverse engineering. One of the most popular range-measuring technologies is laser scanner due to its several advantages: long range, high precision, real-time measurement capabilities, and no dependence on lighting conditions. However, laser scanners are very costly. Their high cost prevents widespread use in applications. Due to the latest developments in technology, now, low-cost, reliable, faster, and light-weight 1D laser range finders (LRFs) are available. A low-cost 1D LRF with a scanning mechanism, providing the ability of laser beam steering for additional dimensions, enables to capture a depth map. In this work, we present an unsynchronized scanning with a low-cost LRF to decrease scanning period and reduce vibrations caused by stop-scan in synchronized scanning. Moreover, we developed an algorithm for alignment of unsynchronized raw data and proposed range image post-processing framework. The proposed technique enables to have a range imaging system for a fraction of the price of its counterparts. The results prove that the proposed method can fulfill the need for a low-cost laser scanning for range imaging for static environments because the most significant limitation of the method is the scanning period which is about 2 minutes for 55,000 range points (resolution of 250x220 image). In contrast, scanning the same image takes around 4 minutes in synchronized scanning. Once faster, longer range, and narrow beam LRFs are available, the methods proposed in this work can produce better results.

  3. Capillary electrophoresis hyphenated with UV-native-laser induced fluorescence detection (CE/UV-native-LIF).

    Science.gov (United States)

    Couderc, François; Ong-Meang, Varravaddheay; Poinsot, Véréna

    2017-01-01

    Native laser-induced fluorescence using UV lasers associated to CE offers now a large related literature, for now 30 years. The main works have been performed using very expensive Ar-ion lasers emitting at 257 and 275 nm. They are not affordable for routine analyses, but have numerous applications such as protein, catecholamine, and indolamine analysis. Some other lasers such as HeCd 325 nm have been used but only for few applications. Diode lasers, emitting at 266 nm, cheaper, are extensively used for the same topics, even if the obtained sensitivity is lower than the one observed using the costly UV-Ar-ion lasers. This review presents various CE or microchips applications and different UV lasers used for the excitation of native fluorescence. We showed that CE/Native UV laser induced fluorescence detection is very sensitive for detection as well as small aromatic biomolecules than proteins containing Trp and Tyr amino acids. Moreover, it is a simple way to analyze biomolecules without derivatization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. High-precision absolute distance measurement using dual-laser frequency scanned interferometry under realistic conditions

    International Nuclear Information System (INIS)

    Yang, H.-J.; Nyberg, Sven; Riles, Keith

    2007-01-01

    In this paper, we report on new high-precision absolute distance measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distances were determined by counting the interference fringes produced while scanning the frequencies of the two chopped lasers. High-finesse Fabry-Perot interferometers were used to determine frequency changes during scanning. Dual lasers with oppositely scanning directions, combined with a multi-distance-measurement technique previously reported, were used to cancel drift errors and to suppress vibration effects and interference fringe uncertainties. Under realistic conditions, a precision about 0.2μm was achieved for a distance of 0.41m. With a precision that exceeds requirements, the frequency scanned interferometry is a promising high-precision optical alignment technique for International Linear Collider silicon tracker detector

  5. Evolution of MEMS scanning mirrors for laser projection in compact consumer electronics

    Science.gov (United States)

    Tauscher, Jason; Davis, Wyatt O.; Brown, Dean; Ellis, Matt; Ma, Yunfei; Sherwood, Michael E.; Bowman, David; Helsel, Mark P.; Lee, Sung; Coy, John Wyatt

    2010-02-01

    The applicability of MOEMS scanning mirrors towards the creation of "flying spot" scanned laser displays is well established. The extension of this concept towards compact embedded pico-projectors has required an evolution of scanners and packaging to accommodate the needs of the consumer electronics space. This paper describes the progression of the biaxial MOEMS scanning mirrors developed by Microvision over recent years. Various aspects of the individual designs are compared. Early devices used a combination of magnetic quasistatic actuation and resonant electrostatic operation in an evacuated atmosphere to create a projection engine for retinal scanned displays. Subsequent designs realized the elimination of both the high voltage electrostatic drive and the vacuum package, and a simplification of the actuation scheme through proprietary technical advances. Additional advances have doubled the scan angle capability and greatly miniaturized the MOEMS component while not incurring significant increase in power consumption, making it an excellent fit for the consumer pico-projector application. The simplicity of the scanned laser-based pico-projector optical design enables high resolution and a large effective image size in a thin projection engine, all of which become critical both to the viability of the technology and adoption by consumers. Microvision's first scanned laser pico-projector is built around a MOEMS scanning mirror capable of projecting 16:9 aspect ratio, WVGA display within a 6.6 mm high package. Further evolution on this path promises continued improvement in resolution, size, and power.

  6. High-efficient Nd:YAG microchip laser for optical surface scanning

    Science.gov (United States)

    Šulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

    2017-12-01

    A CW operating, compact, high-power, high-efficient diode pumped 1064nm laser, based on Nd:YAG active medium, was developed for optical surface scanning and mapping applications. To enhance the output beam quality, laser stability, and compactness, a microchip configuration was used. In this arrangement the resonator mirrors were deposited directly on to the laser crystal faces. The Nd-doping concentration was 1 at.% Nd/Y. The Nd:YAG crystal was 5mm long. The laser resonator without pumping radiation recuperation was investigated {the output coupler was transparent for pumping radiation. For the generated laser radiation the output coupler reflectivity was 95%@1064 nm. The diameter of the samples was 5 mm. For the laser pumping two arrangements were investigated. Firstly, a fibre coupled laser diode operating at wavelength 808nm was used in CW mode. The 400 ¹m fiber was delivering up to 14W of pump power amplitude to the microchip laser. The maximum CW output power of 7.2W @ 1064nm in close to TEM00 beam was obtained for incident pumping power 13.7W @ 808 nm. The differential efficiency in respect to the incident pump power reached 56 %. Secondly, a single-emitter, 1W laser diode operating at 808nm was used for Nd:YAG microchip pumping. The laser pumping was directly coupled into the microchip laser using free-space lens optics. Slope efficiency up to 70% was obtained in stable, high-quality, 1064nm laser beam with CW power up to 350mW. The system was successfully used for scanning of super-Gaussian laser mirrors reflectivity profile.

  7. LabVIEW control software for scanning micro-beam X-ray fluorescence spectrometer.

    Science.gov (United States)

    Wrobel, Pawel; Czyzycki, Mateusz; Furman, Leszek; Kolasinski, Krzysztof; Lankosz, Marek; Mrenca, Alina; Samek, Lucyna; Wegrzynek, Dariusz

    2012-05-15

    Confocal micro-beam X-ray fluorescence microscope was constructed. The system was assembled from commercially available components - a low power X-ray tube source, polycapillary X-ray optics and silicon drift detector - controlled by an in-house developed LabVIEW software. A video camera coupled to optical microscope was utilized to display the area excited by X-ray beam. The camera image calibration and scan area definition software were also based entirely on LabVIEW code. Presently, the main area of application of the newly constructed spectrometer is 2-dimensional mapping of element distribution in environmental, biological and geological samples with micrometer spatial resolution. The hardware and the developed software can already handle volumetric 3-D confocal scans. In this work, a front panel graphical user interface as well as communication protocols between hardware components were described. Two applications of the spectrometer, to homogeneity testing of titanium layers and to imaging of various types of grains in air particulate matter collected on membrane filters, were presented. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Metastable Magnesium fluorescence spectroscopy using a frequency-stabilized 517 nm laser

    DEFF Research Database (Denmark)

    He, Ming; Jensen, Brian B; Therkildsen, Kasper T

    2009-01-01

    We present a laser operating at 517 nm for our Magnesium laser-cooling and atomic clock project. A two-stage Yb-doped fiber amplifier (YDFA) system generates more than 1.5 W of 1034 nm light when seeded with a 15 mW diode laser. Using a periodically poled lithium niobate (PPLN) waveguide, we obta...... obtained more than 40 mW of 517 nm output power by single pass frequency doubling. In addition, fluorescence spectroscopy of metastable magnesium atoms could be used to stabilize the 517 nm laser to an absolute frequency within 1 MHz.......We present a laser operating at 517 nm for our Magnesium laser-cooling and atomic clock project. A two-stage Yb-doped fiber amplifier (YDFA) system generates more than 1.5 W of 1034 nm light when seeded with a 15 mW diode laser. Using a periodically poled lithium niobate (PPLN) waveguide, we...

  9. Sensitive detection and separation of fluorescent derivatives using capillary electrophoresis with laser-induced fluorescence detection with 532nm Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Vrabel, Patrik [Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Taborsky, Petr [Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Ryvolova, Marketa [Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Havel, Josef [Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Preisler, Jan [Department of Analytical Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic)]. E-mail: preisler@chemi.muni.cz

    2006-06-15

    Capillary electrophoresis with laser-induced fluorescence detection (CELIF) is a powerful tool for separation and sensitive determination of fluorescent species. Biologically active compounds, such as amino acids, peptides and proteins may exhibit native fluorescence, which is however often low and/or an expensive laser is required for excitation in UV. Therefore, labelling of the analytes with a fluorescent dye is usually necessary. In this work, a home-built CELIF instrument with diode pumped frequency-doubled continuous wave Nd:YAG excitation laser with feedback power regulation (532nm) was constructed. The suitability of this type of laser for LIF detection in a separation method was found excellent. A limit of detection (LOD) (S/N=3) of 2x10{sup -13}mol/l was achieved with rhodamine B, which is comparable to those obtained using similar instruments with Ar{sup +} laser [Y.F. Cheng, N.J. Dovichi, Science 242 (1988) 562, E.S. Yeung et al., J. Chromatogr. 608 (1992) 73]. LOD of a protein derivatized according to modified procedures [M.J. Little et al., Anal. Chim. Acta 339 (1997) 279, A. Chersi et al., Biochim. Biophys. Acta 1336 (1997) 83] was determined. Detection of the derivatives was found to be limited by insufficient reaction recovery at low analyte concentration, chemical noise, separation efficiency and quality of the derivatizing reagent rather than by the detector performance. As a consequence, a huge gap between the detection ability of CELIF instruments and LOD determined in real samples is revealed.

  10. Control and analysis software for a laser scanning microdensitometer

    Indian Academy of Sciences (India)

    and 2D scans and analysis of spatial or spectral data on X-ray films, such as opti- cal density, intensity and ... ming language with very strong library functions and it also supports direct input/output programming. 5. ... next step” sequence, the spatial resolution remains unaffected by change of speed. Then the program ...

  11. Control and analysis software for a laser scanning microdensitometer

    Indian Academy of Sciences (India)

    ... a user-friendly Graphical User Interface (GUI) to analyse the scanned data and also store the analysed data/image in popular formats like data in Excel and images in jpeg. It has also on-line calibration facility with standard optical density tablets. The control software and data acquisition system is simple, inexpensive and ...

  12. In vitro performance of DIAGNOdent laser fluorescence device for dental calculus detection on human tooth root surfaces

    Directory of Open Access Journals (Sweden)

    Thomas E. Rams

    2017-10-01

    Conclusions: Excellent intra- and inter-examiner reproducibility of autofluorescence intensity measurements was obtained with the DIAGNOdent laser fluorescence device on human tooth roots. Calculus-positive root surfaces exhibited significantly greater DIAGNOdent laser autofluorescence than calculus-free tooth roots, even with the laser probe tip directed parallel to root surfaces. These findings provide further in vitro validation of the potential utility of a DIAGNOdent laser fluorescence device for identifying dental calculus on human tooth root surfaces.

  13. Metastable Magnesium fluorescence spectroscopy using a frequency-stabilized 517 nm laser

    DEFF Research Database (Denmark)

    He, Ming; Jensen, Brian B; Therkildsen, Kasper T

    2009-01-01

    We present a laser operating at 517 nm for our Magnesium laser-cooling and atomic clock project. A two-stage Yb-doped fiber amplifier (YDFA) system generates more than 1.5 W of 1034 nm light when seeded with a 15 mW diode laser. Using a periodically poled lithium niobate (PPLN) waveguide, we...... obtained more than 40 mW of 517 nm output power by single pass frequency doubling. In addition, fluorescence spectroscopy of metastable magnesium atoms could be used to stabilize the 517 nm laser to an absolute frequency within 1 MHz....

  14. Slope excavation quality assessment and excavated volume calculation in hydraulic projects based on laser scanning technology

    Directory of Open Access Journals (Sweden)

    Chao Hu

    2015-04-01

    Full Text Available Slope excavation is one of the most crucial steps in the construction of a hydraulic project. Excavation project quality assessment and excavated volume calculation are critical in construction management. The positioning of excavation projects using traditional instruments is inefficient and may cause error. To improve the efficiency and precision of calculation and assessment, three-dimensional laser scanning technology was used for slope excavation quality assessment. An efficient data acquisition, processing, and management workflow was presented in this study. Based on the quality control indices, including the average gradient, slope toe elevation, and overbreak and underbreak, cross-sectional quality assessment and holistic quality assessment methods were proposed to assess the slope excavation quality with laser-scanned data. An algorithm was also presented to calculate the excavated volume with laser-scanned data. A field application and a laboratory experiment were carried out to verify the feasibility of these methods for excavation quality assessment and excavated volume calculation. The results show that the quality assessment indices can be obtained rapidly and accurately with design parameters and scanned data, and the results of holistic quality assessment are consistent with those of cross-sectional quality assessment. In addition, the time consumption in excavation quality assessment with the laser scanning technology can be reduced by 70%–90%, as compared with the traditional method. The excavated volume calculated with the scanned data only slightly differs from measured data, demonstrating the applicability of the excavated volume calculation method presented in this study.

  15. Laser scanning graphic system for multimedia podium presentations

    Science.gov (United States)

    Gadhok, Jagmohan S.; Belur, Raghu R.; Strganac, Thomas W.; Junkins, John L.

    1997-07-01

    The present paper introduces new electro-optical sensing technology for electronic blackboard and related passive stereo measurement applications. The electronic blackboard enables real-time digitization of hand-written and hand-drawn information using a totally passive writing surface and writing instrument. Two resonant laser scanners sweep out a plane, the angular position of the two beams (at the instants that the beams are interrupted by the laser beams of a hand- held stylus such as a felt tip marker) are detected. These data are used to digitize coordinates along hand-drawn lines with high precision (approximately 1 part in 25,000) and digitization rates (approximately 160 Hz). The data input surface dimensions vary from small to large (permitting digitization on wall-sized writing surfaces as large as 2 meters by 6 meters) thus enabling a new family of applications. In particular, we discuss a novel application of this laser digitizing system to the automation of class or conference room presentations, and the authors describe a newly developed multimedia podium for classroom presentations. Other applications exist in emerging multi-media systems, manufacturing and robotics, large area digitizing for the drafting market, and automated note taking for the education market.

  16. Functional and ophthalmoscopic observations in human laser accident cases using scanning-laser ophthalmoscopy

    Science.gov (United States)

    Zwick, Harry; Lund, David J.; Gagliano, Donald A.; Stuck, Bruce E.

    1994-06-01

    A scanning laser ophthalmoscope (SLO) equipped with an acousto- optical modulator (ACM) was used to make focal acuity and contrast sensitivity measurements in individuals with macular damage. The depth of modulation achieved by the ACM was determined by imaging the SLO raster pattern onto a Pulnix TM 745 video camera and evaluating the intensity distribution with a Big Sky BVA10 beam view analyzer. Contrast levels remained approximately constant over the entire range of SLO input raster power settings. A delta Technologies image processing system produced Landolt ring test stimuli at the center of the raster pattern. Contrast thresholds were determined at various retinal locations by having subjects fixate a specific location on a fixed grid imaged on the raster pattern. This procedure insured that the test stimuli were always imaged in the center of the raster pattern thereby avoiding peripheral variations in the raster pattern intensity distribution. Measurements of contrast sensitivity where focal test targets fell within the macular damage area demonstrated elevated contrast thresholds relative to retinal locations where focal test targets evaluated the border regions between normal and pathological retina.

  17. A 3-d laser scanning system and scan data processing method for the monitoring of tunnel deformations

    Science.gov (United States)

    Chmelina, Klaus; Jansa, Josef; Hesina, Gerd; Traxler, Christoph

    2012-11-01

    The paper presents the mobile multi-sensor system Orthos Plus for the monitoring and mapping of tunnel walls, a scan data processing method for the evaluation of 3-d tunnel wall displacements from subsequent wall scans and, finally, a virtual reality tool supporting the interpretation of data. The measuring system consists of a 3-d laser scanner, a motorised total station and a digital camera that are integrated on a light metal frame that is installed on a mobile platform. It has been designed to perform tunnel measurements most efficiently and to meet the special requirements of tunnels under construction. The evaluation of 3-d displacements is based on a 3-d matching algorithm that takes advantage of the particular conditions of tunnel (shotcrete) surfaces. The virtual reality tool allows viewing of data in a 3-d virtual reality tunnel model and their animation in time and space in order supports understanding in an optimal way. The measuring system Orthos Plus has been developed in the course of a national research project, the 3-d matching method in the frame of the Austrian Christian Doppler Laboratory Spatial Data from Laser Scanning and Remote Sensing and the VR tool in the Austrian COMET K1 Competence Center VRVis Center (www.vrvis.at).

  18. Studies of the laser-induced fluorescence of explosives and explosive compositions.

    Energy Technology Data Exchange (ETDEWEB)

    Hargis, Philip Joseph, Jr. (,; .); Thorne, Lawrence R.; Phifer, Carol Celeste; Parmeter, John Ethan; Schmitt, Randal L.

    2006-10-01

    Continuing use of explosives by terrorists throughout the world has led to great interest in explosives detection technology, especially in technologies that have potential for standoff detection. This LDRD was undertaken in order to investigate the possible detection of explosive particulates at safe standoff distances in an attempt to identify vehicles that might contain large vehicle bombs (LVBs). The explosives investigated have included the common homogeneous or molecular explosives, 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), cyclonite or hexogen (RDX), octogen (HMX), and the heterogeneous explosive, ammonium nitrate/fuel oil (ANFO), and its components. We have investigated standard excited/dispersed fluorescence, laser-excited prompt and delayed dispersed fluorescence using excitation wavelengths of 266 and 355 nm, the effects of polarization of the laser excitation light, and fluorescence imaging microscopy using 365- and 470-nm excitation. The four nitro-based, homogeneous explosives (TNT, PETN, RDX, and HMX) exhibit virtually no native fluorescence, but do exhibit quenching effects of varying magnitude when adsorbed on fluorescing surfaces. Ammonium nitrate and fuel oil mixtures fluoresce primarily due to the fuel oil, and, in some cases, due to the presence of hydrophobic coatings on ammonium nitrate prill or impurities in the ammonium nitrate itself. Pure ammonium nitrate shows no detectable fluorescence. These results are of scientific interest, but they provide little hope for the use of UV-excited fluorescence as a technique to perform safe standoff detection of adsorbed explosive particulates under real-world conditions with a useful degree of reliability.

  19. Planarization Profile Measurement Using A Confocal Scanning Laser Microscope

    Science.gov (United States)

    Smith, Ian R.; Bennett, Simon D.; Lindow, James T.; Monahan, Kevin

    1986-08-01

    The use of planarizing layers to improve the performance of photolithography for micron and submicron devices is being actively explored by a number of semiconductor companies. The usefulness of the procedure depends critically upon the degree to which residual surface undulations can be controlled. This paper describes how a confocal scanning optical microscope may be used to measure surface profiles of planarizing layers and discusses the factors which influence the accuracy of measurement. Experimental measurements, using a SiScan-I system, of resist and P.S.G. planarizing layers are presented, demonstrating a sensitivity to surface height changes of 50 nm. The technique may be improved upon by careful design of the microscope and selection of the imaging wavelength. These factors are discussed.

  20. Il laser scanning e CloudCUBE per le grotte di Naica

    Directory of Open Access Journals (Sweden)

    Erminio Paolo Canevese

    2008-03-01

    Full Text Available Laser scanning and CloudCube for Naica caves On May 2007, Virtualgeo, a geomatic software development and communication company, took part in the first official expedition to Mexico. The Project, coined "Naica", involves researchers from ten universities, four companies and several laboratories. Virtualgeo carried out the survey by applying laser scanning technology to hypogeal caves covered with selenite crystals. The data was processed using CloudCUBE, a proprietary software designed to manage and model 3D point clouds. The first results of the laser scanning survey of a spectacular “forest of crystals” are presented here.

  1. Il laser scanning e CloudCUBE per le grotte di Naica

    Directory of Open Access Journals (Sweden)

    Erminio Paolo Canevese

    2008-03-01

    Full Text Available Laser scanning and CloudCube for Naica cavesOn May 2007, Virtualgeo, a geomatic software development and communication company, took part in the first official expedition to Mexico. The Project, coined "Naica", involves researchers from ten universities, four companies and several laboratories. Virtualgeo carried out the survey by applying laser scanning technology to hypogeal caves covered with selenite crystals. The data was processed using CloudCUBE, a proprietary software designed to manage and model 3D point clouds. The first results of the laser scanning survey of a spectacular “forest of crystals” are presented here.

  2. Studies of porphyrin-containing specimens using an optical spectrometer connected to a confocal scanning laser microscope.

    Science.gov (United States)

    Trepte, O; Rokahr, I; Andersson-Engels, S; Carlsson, K

    1994-12-01

    A spectrometer has been developed for use with a confocal scanning laser microscope. With this unit, spectral information from a single point or a user-defined region within the microscope specimen can be recorded. A glass prism is used to disperse the spectral components of the recorded light over a linear CCD photodiode array with 256 elements. A regulated cooling unit keeps the detector at 277 K, thereby allowing integration times of up to 60 s. The spectral resolving power, lambda/delta lambda, ranges from 350 at lambda = 400 nm to 100 at lambda = 700 nm. Since the entrance aperture of the spectrometer has the same size as the detector pinhole used during normal confocal scanning, the three-dimensional spatial resolution is equivalent to that of normal confocal scanning. Light from the specimen is deflected to the spectrometer by a solenoid controlled mirror, allowing fast and easy switching between normal confocal scanning and spectrometer readings. With this equipment, studies of rodent liver specimens containing porphyrins have been made. The subcellular localization is of interest for the mechanisms of photodynamic therapy (PDT) of malignant tumours. Spectroscopic detection is necessary to distinguish the porphyrin signal from other fluorescent components in the specimen. Two different substances were administered to the tissue, Photofrin, a haematoporphyrin derivative (HPD) and delta-amino levulinic acid (ALA), a precursor to protoporphyrin IX and haem in the haem cycle. Both are substances under clinical trials for PDT of malignant tumours. Following administration of these compounds to the tissue, the potent photosensitizer and fluorescent compound Photofrin, or protoporphyrin IX, respectively, is accumulated.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Automatic concrete cracks detection and mapping of terrestrial laser scan data

    Directory of Open Access Journals (Sweden)

    Mostafa Rabah

    2013-12-01

    The current paper submits a method for automatic concrete cracks detection and mapping from the data that was obtained during laser scanning survey. The method of cracks detection and mapping is achieved by three steps, namely the step of shading correction in the original image, step of crack detection and finally step of crack mapping and processing steps. The detected crack is defined in a pixel coordinate system. To remap the crack into the referred coordinate system, a reverse engineering is used. This is achieved by a hybrid concept of terrestrial laser-scanner point clouds and the corresponding camera image, i.e. a conversion from the pixel coordinate system to the terrestrial laser-scanner or global coordinate system. The results of the experiment show that the mean differences between terrestrial laser scan and the total station are about 30.5, 16.4 and 14.3 mms in x, y and z direction, respectively.

  4. Multibeam scanning optics with single laser source for full-color printers.

    Science.gov (United States)

    Maruo, S; Arimoto, A; Kobayashi, S

    1997-10-01

    In the novel optical system described here, four-color toners can be developed in one rotation of the photoconductor, and the color control information is given when the intensities of the laser power levels are changed and the two polarization directions are switched. A polarizing beam splitter between the common scanning optics and the photoconductor enables the laser beam to pass through a common scanning system and to illuminate two positions on the photoconductive material. The laser beam polarization direction is controlled by an electro-optical device immediately behind the laser. In each illuminated position, two-color toners are developed by a three-level (trilevel) photographic process. This simplified optical system eliminates the registration errors that occur with four-color information items and can be useful in high-speed printing systems.

  5. Graph Structure-Based Simultaneous Localization and Mapping Using a Hybrid Method of 2D Laser Scan and Monocular Camera Image in Environments with Laser Scan Ambiguity

    Directory of Open Access Journals (Sweden)

    Taekjun Oh

    2015-07-01

    Full Text Available Localization is an essential issue for robot navigation, allowing the robot to perform tasks autonomously. However, in environments with laser scan ambiguity, such as long corridors, the conventional SLAM (simultaneous localization and mapping algorithms exploiting a laser scanner may not estimate the robot pose robustly. To resolve this problem, we propose a novel localization approach based on a hybrid method incorporating a 2D laser scanner and a monocular camera in the framework of a graph structure-based SLAM. 3D coordinates of image feature points are acquired through the hybrid method, with the assumption that the wall is normal to the ground and vertically flat. However, this assumption can be relieved, because the subsequent feature matching process rejects the outliers on an inclined or non-flat wall. Through graph optimization with constraints generated by the hybrid method, the final robot pose is estimated. To verify the effectiveness of the proposed method, real experiments were conducted in an indoor environment with a long corridor. The experimental results were compared with those of the conventional GMappingapproach. The results demonstrate that it is possible to localize the robot in environments with laser scan ambiguity in real time, and the performance of the proposed method is superior to that of the conventional approach.

  6. Demonstration of up-conversion fluorescence from Ar clusters in intense free-electron-laser fields.

    Science.gov (United States)

    Iwayama, Hiroshi; Nagasono, Mitsuru; Harries, James R; Shigemasa, Eiji

    2012-10-08

    Extreme ultraviolet (EUV) fluorescence emitted from Ar clusters irradiated by intense EUV free electron laser (FEL) pulses has been investigated. The EUV fluorescence spectra display rich structure at wavelengths shorter than the incident FEL wavelength of 51 nm. The results suggest that multiply-charged ions are produced following the ion-electron recombination processes which occur in the nanoplasma created by multi-photon excitation during the intense EUV-FEL pulses.

  7. Analysis of laser-induced fluorescence spectra of in vitro plant tissue cultures

    Science.gov (United States)

    Muñoz-Muñoz, Ana Celia; Gutiérrez-Pulido, Humberto; Rodríguez-Domínguez, José Manuel; Gutiérrez-Mora, Antonia; Rodríguez-Garay, Benjamín; Cervantes-Martínez, Jesús

    2007-04-01

    We demonstrate the effectiveness of laser-induced fluorescence (LIF) for monitoring the development and stress detection of in vitro tissue cultures in a nondestructive and noninvasive way. The changes in LIF spectra caused by the induction of organogenesis, the increase of the F690/F740 ratio as a result of the stress originated in the organogenic explants due to shoot emergence, and the relationship between fluorescence spectra and shoot development were detected by LIF through closed containers of Saintpaulia ionantha.

  8. Laser fluorescence in monitoring the influence of targeted tooth brushing on remineralization of initial caries lesions on newly erupted molar teeth - RCT.

    Science.gov (United States)

    Laitala, M-L; Jaanti, E; Vähänikkilä, H; Määttä, T; Heikka, H; Hausen, H; Anttonen, V

    2017-11-01

    This study aimed to monitor mineralization changes in initial caries lesions on newly erupted second molars using laser fluorescence (LF) scanning after a 1-month targeted tooth brushing intervention. Altogether, 124 13- to 14-year-old school children were invited to participate. Of those who fulfilled the clinical criteria (at least one initial lesion with LF value >10 in second molars), 51 gave their written consent to participate. Laser fluorescence values were registered at baseline and after 1-month follow-up period. All participants were individually taught targeted tooth brushing of their second molars and randomly provided tooth paste with 0 or 1500 ppm fluoride. Brushing frequency was investigated at baseline and after the follow-up. Change in LF values was compared considering the tooth, content of fluoride in the paste and brushing frequency. In lesions with LF values ≤30 at baseline, change in LF values demonstrated improvement. Improvement was detected especially in upper molars. In lesions with LF values >30 at baseline, improvement was least detected. Brushing frequency increased slightly during the intervention. Laser fluorescence is a simple method and useful in monitoring remineralization of incipient lesions even in weeks. Targeted tooth brushing seems to induce remineralization even in weeks. Laser fluorescence could be a valuable motivating tool in promoting patients' self-care. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Three-dimensional laser-induced fluorescence measurements of turbulent chemical plumes

    Science.gov (United States)

    True, Aaron; Crimaldi, John

    2017-11-01

    In order to find prey, mates, and suitable habitat, many organisms must navigate through complex chemical plume structures in turbulent flow environments. In this context, we investigate the spatial and temporal structure of chemical plumes released isokinetically into fractal-grid-generated turbulence in an open channel flow. We first utilized particle image velocimetry (PIV) to characterize flow conditions (mean free stream velocities, turbulence intensities, turbulent kinetic energy dissipation rates, Taylor Reynolds numbers). We then implemented a newly developed high-resolution, high-speed, volumetric scanning laser-induced fluorescence (LIF) system for near time-resolved measurements of three-dimensional chemical plume structures. We investigated cases with and without a cylinder wake, and compare statistical (mean, variance, intermittency, probability density functions) and spectral (power spectrum of concentration fluctuations) characteristics of the chemical plume structure. Stretching and folding of complex three-dimensional filament structures during chaotic turbulent mixing is greatly enhanced in the cylinder wake case. In future experiments, we will implement simultaneous PIV and LIF, enabling computation of the covariance of the velocity and chemical concentration fluctuations and thus estimation of turbulent eddy diffusivities. NSF PHY 1555862.

  10. Investigation of lasers based on coupled waveguides by near-field scanning optical microscopy

    Science.gov (United States)

    Polubavkina, Yu S.; Gordeev, N. Yu; Payusov, A. S.; Kryzhanovskaya, N. V.; Moiseev, E. I.; Zubov, F. I.; Mintairov, S. A.; Kalyuzhnyy, N. A.; Kulagina, M. M.; Shernyakov, Yu M.; Maximov, M. V.; Zhukov, A. E.

    2017-11-01

    We have investigated near field intensity distributions of InGaAs/GaAs/AlGaAs lasers possessing broadened waveguides based on coupled large optical cavity structures (CLOC) by scanning near-field optical microscopy (SNOM). The concept allows effective suppressing of the transverse high-order mode lasing. The obtained results can be considered to be the direct proof of pure transverse single-mode emission of the CLOC lasers.

  11. Laser fluorescence determination of radioactive waste cotton fabric in the exploration of uranium content

    International Nuclear Information System (INIS)

    Wang Jiangong

    2010-01-01

    In order to meet the dosage test the operational needs of the laser fluorescence determination of trace radioactive waste cotton fabric uranium research and exploration, to determine the sample ashing time, measured dosage of acidity and digestion and other technical parameters, gives the laser fluorescence determination of radioactive abandoned cotton fabric of trace uranium method. Method of high sensitivity, strong anti-interference, the detection limit of 0.025μg/g(Burning down dregs), relative standard deviation was 3.96%, the mean recovery 93.3%-103% for masks, gloves and other radioactive waste to the determination of trace uranium. (authors)

  12. Determination of lead in clay enameled by X-ray fluorescence technique in Total reflection and by Scanning Electron Microscopy

    International Nuclear Information System (INIS)

    Zarazua O, G.; Carapia M, L.

    2000-01-01

    This work has the objective of determining lead free in the glazed commercial stewing pans using the X-ray fluorescence technique in Total reflection (FRX) and the observation and semiquantitative determination of lead by Analytical Scanning Electron Microscopy (ASEM). (Author)

  13. 3D imaging of cement-based materials at submicron resolution by combining laser scanning confocal microscopy with serial sectioning.

    Science.gov (United States)

    Yio, M H N; Mac, M J; Wong, H S; Buenfeld, N R

    2015-05-01

    In this paper, we present a new method to reconstruct large volumes of nontransparent porous materials at submicron resolution. The proposed method combines fluorescence laser scanning confocal microscopy with serial sectioning to produce a series of overlapping confocal z-stacks, which are then aligned and stitched based on phase correlation. The method can be extended in the XY plane to further increase the overall image volume. Resolution of the reconstructed image volume does not degrade with increase in sample size. We have used the method to image cementitious materials, hardened cement paste and concrete and the results obtained show that the method is reliable. Possible applications of the method such as three-dimensional characterization of the pores and microcracks in hardened concrete, three-dimensional particle shape characterization of cementitious materials and three-dimensional characterization of other porous materials such as rocks and bioceramics are discussed. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  14. Laser Induced Fluorescence For Measurement Of Lignin Concentrations In Pulping Liquors

    Science.gov (United States)

    Horvath, J. J.; Semerjian, H. G.; Biasca, K. L.; Attala, R.

    1988-11-01

    Laser excited fluorescence of pulping liquors was investigated for use in the pulp and paper industry for process measurement and control applications. Liquors from both mill and laboratory cooks were studied. A Nd-YAG pumped dye laser was used to generate the excitation wavelength of 280 nm; measurements were also performed using a commercially available fluorometer. Measurements on mill pulping liquors gave strong signals and showed changes in the fluorescence intensity during the cook. Absorption spectra of diluted mill liquor samples showed large changes during the cook. Samples from well controlled and characterized laboratory cooks showed fluorescence to be linear with concentration over two decades with an upper limit of approximately 1000 ppm dissolved lignin. At the end of these cooks a possible chemical change was indicated by an increase in the observed fluorescence intensity. Results indicate that lignin concentrations in pulping liquors can be accurately determined with fluorescence in the linear optical region over a greater dynamic range than absorption spectroscopy. Laser induced fluorescence may also provide an indication of chemical changes occurring in the lignin structure during a cook.

  15. MULTISPECTRAL AIRBORNE LASER SCANNING - A NEW TREND IN THE DEVELOPMENT OF LIDAR TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Bakuła Krzysztof

    2015-12-01

    Full Text Available Airborne laser scanning (ALS is the one of the most accurate remote sensing techniques for data acquisition where the terrain and its coverage is concerned. Modern scanners have been able to scan in two or more channels (frequencies of the laser recently. This gives the rise to the possibility of obtaining diverse information about an area with the different spectral properties of objects. The paper presents an example of a multispectral ALS system - Titan by Optech - with the possibility of data including the analysis of digital elevation models accuracy and data density. As a result of the study, the high relative accuracy of LiDAR acquisition in three spectral bands was proven. The mean differences between digital terrain models (DTMs were less than 0.03 m. The data density analysis showed the influence of the laser wavelength. The points clouds that were tested had average densities of 25, 23 and 20 points per square metre respectively for green (G, near-infrared (NIR and shortwave-infrared (SWIR lasers. In this paper, the possibility of the generation of colour composites using orthoimages of laser intensity reflectance and its classification capabilities using data from airborne multispectral laser scanning for land cover mapping are also discussed and compared with conventional photogrammetric techniques.

  16. A flexible 3D laser scanning system using a robotic arm

    Science.gov (United States)

    Fei, Zixuan; Zhou, Xiang; Gao, Xiaofei; Zhang, Guanliang

    2017-06-01

    In this paper, we present a flexible 3D scanning system based on a MEMS scanner mounted on an industrial arm with a turntable. This system has 7-degrees of freedom and is able to conduct a full field scan from any angle, suitable for scanning object with the complex shape. The existing non-contact 3D scanning system usually uses laser scanner that projects fixed stripe mounted on the Coordinate Measuring Machine (CMM) or industrial robot. These existing systems can't perform path planning without CAD models. The 3D scanning system presented in this paper can scan the object without CAD models, and we introduced this path planning method in the paper. We also propose a practical approach to calibrating the hand-in-eye system based on binocular stereo vision and analyzes the errors of the hand-eye calibration.

  17. Laser-excited atomic-fluorescence spectrometry with electrothermal tube atomization.

    Science.gov (United States)

    Vera, J A; Leong, M B; Stevenson, C L; Petrucci, G; Winefordner, J D

    1989-12-01

    The performance of graphite-tube electrothermal atomizers is evaluated for laser-excited atomic-fluorescence spectrometry for several elements. Three pulsed laser systems are used to pump tunable dye lasers which subsequently are used to excite Pb, Ga, In, Fe, Ir, and Tl atoms in the hot graphite tube. The dye laser systems used are pumped by nitrogen, copper vapour and Nd:YAG lasers. Detection limits in the femtogram and subfemtogram range are typically obtained for all elements. A commercial graphite-tube furnace is important for the successful utilization of the laser-based method when the determination of trace elements is intended, especially when complicated matrices may be present.

  18. Dynamic model of thermal reaction of biological tissues to laser-induced fluorescence and photodynamic therapy.

    Science.gov (United States)

    Seteikin, Alexey Yu; Krasnikov, Ilya V; Drakaki, Eleni; Makropoulou, Mersini

    2013-07-01

    The aim of this work was to evaluate the temperature fields and the dynamics of heat conduction into the skin tissue under several laser irradiation conditions with both a pulsed ultraviolet (UV) laser (λ=337  nm) and a continuous-wave (cw) visible laser beam (λ=632.8  nm) using Monte Carlo modeling. Finite-element methodology was used for heat transfer simulation. The analysis of the results showed that heat is not localized on the surface, but is collected inside the tissue in lower skin layers. The simulation was made with the pulsed UV laser beam (used as excitation source in laser-induced fluorescence) and the cw visible laser (used in photodynamic therapy treatments), in order to study the possible thermal effects.

  19. CTC staining and counting of actively respiring bacteria in natural stone using confocal laser scanning microscopy.

    Science.gov (United States)

    Bartosch, S; Mansch, R; Knötzsch, K; Bock, E

    2003-01-01

    A method was established for staining and counting of actively respiring bacteria in natural stone by using the tetrazolium salt 5-cyano-2,3-ditolyltetrazolium chloride (CTC) in combination with confocal laser scanning microscopy (CLSM). Applying 5 mM CTC for 2 h to pure cultures of representative stone-inhabiting microorganisms showed that chemoorganotrophic bacteria and fungi-in contrast to lithoautotrophic nitrifying bacteria-were able to reduce CTC to CTF, the red fluorescing formazan crystals of CTC. Optimal staining conditions for microorganisms in stone material were found to be 15 mM CTC applied for 24 h. The cells could be visualized on transparent and nontransparent mineral materials by means of CLSM. A semi-automated method was used to count the cells within the pore system of the stone. The percentage of CTC-stained bacteria was dependent on temperature and humidity of the material. At 28 degrees C and high humidity (maximum water holding capacity) in the laboratory, about 58% of the total bacterial microflora was active. On natural stone exposed for 9 years at an urban exposure site in Germany, 52-56% of the bacterial microflora was active at the east, west, and north side of the specimen, while only 18% cells were active at the south side. This is consistent with microclimatic differences on the south side which was more exposed to sunshine thus causing UV and water stress as well as higher temperatures on a microscale level. In combination with CLSM, staining by CTC can be used as a fast method for monitoring the metabolic activity of chemoorganotrophic bacteria in monuments, buildings of historic interest or any art objects of natural stone. Due to the small size of samples required, the damage to these objects and buildings can be minimized.

  20. ITSC08: IN SITU QUANTITATIVE IMMUNOPROFILING OF REGULATORY T CELLS USING LASER SCANNING CYTOMETRY

    Science.gov (United States)

    Takahashi, Hidenori; Ruiz, Phillip; Ricordi, Camillo; Miki, Atsushi; Mita, Atsuyoshi; Barker, Scott; Tzakis, Andreas; Ichii, Hirohito

    2013-01-01

    Laser scanning cytometry (iCys; CompuCyte) is recently developed methodology that utilizes fluorescence-based quantitative measurements on tissue sections or other cellular preparations at a single-cell level. The purpose of this study was to develop objective quantitative immunoprofiling of regulatory T cells (T regs) on formalin-fixed/paraffin embedded (FFPE) biopsy sample from transplanted allograft using iCys. We analyzed the population of CD4 (+) Foxp3 (+) T regs among the entire CD4 (+) T cells and the entire T cells (the total of CD4 (+) and CD8 (+)) in human intestinal allograft biopsy samples to evaluate the usefulness of iCys. Primary antibodies (Foxp3 and CD4) were incubated on one section. Foxp3 and CD4 were labeled by Alexa Fluoro 488 (Alexa488) and 647 (Alexa647) using polymer HRP and catalyzed signal amplification. On the other section, CD8 and CD4 were labeled by Alexa488 and Alexa647 using the same protocol. Data acquisition was performed using iCys. The signal intensity of Alexa488 and Alexa647 was sufficient to analyze by iCys. Distribution of the integrals of Alexa488 and Alexa647 visualize each cell population and enable to calculate the population of T reg among CD4 (+) T cell, CD4 (+) T cell among the total T cells and T reg among the entire T cells. iCys and signal amplified immunofluorescent staining allowed objective quantitative immunoprofiling of in situ T reg populations, with precise quantitative analysis at a single-cell level on FFPE section. This objective method can be applied on the biopsy sample from various transplant organs. PMID:19249524

  1. [Confocal laser scanning electron microscopy for assessment of vaginal Lactobacillus crispatus biofilm].

    Science.gov (United States)

    Wu, Li-jie; Wang, Ben; Liao, Qin-ping; Zhang, Rui

    2015-12-18

    To investigate the female vaginal Lactobacillus crispatus biofilm by using confocal laser scanning microscopy (CLSM),thus revealing the formation of biofilm. The cover slide biofilm culture approach in vitro was employed for induction of the vaginal Lactobacillus crispatus biofilm formation. Following the culture for 2, 4, 8, 12, 16, 20, 24, 48, 72, 96 and 120 hours, the cover slide was removed for subsequent staining with the fluoresce in isothiocyanate-conjugated concanavalin A(FITC-ConA) and propidium (PI).This was followed by determination of the formation and characteristics of the vaginal Lactobacillus crispatus biofilm by using CLSM. The CLSM images of biofilm formation at different time points were captured, suggesting that the vaginal Lactobacillus crispatus adhesion occurred at h 4, which was in reversible attachment, then more and more Lactobacillus crispatus aggregated at h 8 to h 20, which was in irreversible attachment.Lactobacillus crispatus clustered at h 20, with early development of biofilm architecture.Then the biofilm with extracellular matrix around the bacteria was set up at h 24,with gradual matureation at h 24 to h 48.The biofilm dispersed at h 72. The biofilm density of cultivating for 20 hours was 42.7 × 10⁻³ ± 6.8 × 10⁻³ ,and for 24 hours increased to 102.5 × 10⁻³ ± 23.1 × 10⁻³, suggesting a significant difference, PLactobacillus crispatus is able to form typical biofilm with distinct developmental phases and architecture characteristics.Mature biofilm is formed at h 24 to h 48, then the biofilm begins to disperse.

  2. Optical Design of Adaptive Optics Confocal Scanning Laser Ophthalmoscope with Two Deformable Mirrors.

    Science.gov (United States)

    Yang, Jinsheng; Wang, Yuanyuan; Rao, Xuejun; Wei, Ling; Li, Xiqi; He, Yi

    2017-01-01

    We describe the optical design of a confocal scanning laser ophthalmoscope with two deformable mirrors. Spherical mirrors are used for pupil relay. Defocus aberration of the human eye is corrected by a Badal focusing structure and astigmatism aberration is corrected by a deformable mirror. The main optical system achieves a diffraction-limited performance through the entire scanning field (6 mm pupil, 3 degrees on pupil plane). The performance of the optical system, with correction of defocus and astigmatism, is also evaluated.

  3. Surveying a fossil oyster reef using terrestrial laser scanning

    Science.gov (United States)

    Haring, A.; Exner, U.; Harzhauser, M.

    2009-04-01

    The Korneuburg Basin, situated north-west of Vienna, is well known to contain a rich variety of fossils from the Early Miocene (16.5 ma) and therefore has been investigated extensively by scientists in the past decades. An exceptional discovery was made in 2005: a large fossil oyster reef has been excavated and documented carefully during the last years. Aside from the giant-sized oyster (Crassostrea gryphoides), the excavation site contains numerous species of molluscs along with teeth of sharks and rays and even isolated bones of sea cows. The oysters, having lengths of up to 80 cm, are protruding from the ground surface, which is more or less a tilted plane (25˚ ) with a size of about 300 m2. The entire site is crosscut by a network of geological faults, often also offsetting individual oyster shells. Displacements along the normal faults do not exceed ~ 15 cm. The faulted fossils offer a unique opportunity to measure displacement distribution along the faults in great detail and provide insight in deformation mechanisms in porous, barely lithified sediments. In order to get a precise 3D model of the oyster reef, the terrestrial laser scanner system Leica HDS 6000 is used. It is a phase-based laser scanner, i.e. the distance measurement is performed using the phase-shift principle. Compared to the time-of-flight principle, this method is generally more appropriate to projects like this one, where the distances to be measured are relatively small (aligned randomly or if they show a systematic alignment, in order to draw conclusions on the ocean currents at that time. For data processing, we use the 3D modeling software Geomagic Studio and the DTM (Digital Terrain Model) software SCOP++. The entire site has also been systematically documented by a large number of digital photographs. The obtained texture information allows a visual interpretation of the underlying surface. We discuss in how far such a 3D model derived from terrestrial laser scanner data may be

  4. Teaching laser-induced fluorescence of plant leaves

    Science.gov (United States)

    Lenk, Sándor; Gádoros, Patrik; Kocsányi, László; Barócsi, Attila

    2016-11-01

    Plants convert carbon dioxide into sugars using the energy of sunlight. Absorbed light unused for conversion is dissipated primarily as heat with a small fraction re-emitted as fluorescence at longer wavelengths. One can use the latter to estimate photosynthetic activity. The illumination of intact leaves with strong light after keeping them in dark for tens of minutes results in a rapid increase followed by a slow decay of fluorescence emission from the fluorophore chlorophyll-a, called the Kautsky effect. This paper describes a laboratory practice that introduces students of physics or engineering into this research field. It begins with the spectral measurement of the fluorescence emitted by a plant leaf upon UV excitation. Then it focuses on the red and far-red components of the fluorescence emission spectrum characteristic to the chlorophyll-a molecule and presents an inexpensive demonstration of the Kautsky effect. As researchers use more complex measurement techniques and tools, the practice ends up with the demonstration of an intelligent fluorosensor, a compact tool developed for plant physiological research and horticulture applications together with a brief interpretation of some important fluorescence parameters.

  5. Teaching laser-induced fluorescence of plant leaves

    International Nuclear Information System (INIS)

    Lenk, Sándor; Gádoros, Patrik; Kocsányi, László; Barócsi, Attila

    2016-01-01

    Plants convert carbon dioxide into sugars using the energy of sunlight. Absorbed light unused for conversion is dissipated primarily as heat with a small fraction re-emitted as fluorescence at longer wavelengths. One can use the latter to estimate photosynthetic activity. The illumination of intact leaves with strong light after keeping them in dark for tens of minutes results in a rapid increase followed by a slow decay of fluorescence emission from the fluorophore chlorophyll -a , called the Kautsky effect. This paper describes a laboratory practice that introduces students of physics or engineering into this research field. It begins with the spectral measurement of the fluorescence emitted by a plant leaf upon UV excitation. Then it focuses on the red and far-red components of the fluorescence emission spectrum characteristic to the chlorophyll -a molecule and presents an inexpensive demonstration of the Kautsky effect. As researchers use more complex measurement techniques and tools, the practice ends up with the demonstration of an intelligent fluorosensor, a compact tool developed for plant physiological research and horticulture applications together with a brief interpretation of some important fluorescence parameters. (paper)

  6. Kinetics of proton transfer in a green fluorescent protein: A laser ...

    Indian Academy of Sciences (India)

    Unknown

    triggered by the UV laser shot through a photodiode; thus, the zero of time was deter- mined by the incoming laser flash. This instrument was calibrated by photoactivation of a solution containing 2 mM o-NBA and 1 µM of the fluorescent pH indicator fluorescein at pH 8 (figure 3). The pH jump-induced decrease in ...

  7. Light propagation studies on laser modified waveguides using scanning near-field optical microscopy

    DEFF Research Database (Denmark)

    Borrise, X.; Berini, Abadal Gabriel; Jimenez, D.

    2001-01-01

    microscope (SNOM) has been used. The laser modifications locally changes the optical properties of the waveguide. The change in the effective refractive index is attributed to a TE to TM mode conversion, Thus, the laser modification might be a new way to fabricate optical mode converters.......By means of direct laser writing on Al, a new method to locally modify optical waveguides is proposed. This technique has been applied to silicon nitride waveguides, allowing modifications of the optical propagation along the guide. To study the formed structures, a scanning near-held optical...

  8. Analysis of photoisomerizable dyes using laser absorption and fluorescence techniques

    International Nuclear Information System (INIS)

    Duchowicz, R.; Di Paolo, R.E.; Scaffardi, L.; Tocho, J.O.

    1992-01-01

    The attention of the present report has been directed mainly to the description of laser-based techniques developed in order to obtain kinetic and spectroscopic properties of polymethine cyanine dyes in solution. Special attention was dedicated to photoisomerizable molecules where the absorption spectra of both isomers are strongly overlapped. As an example, measurements of two different dyes of laser technological interest, DTCI and DODCI were performed. The developed methods provide a complete quantitative description of photophysical processes. (author). 14 refs, 6 figs

  9. Retrieval of Gap Fraction and Effective Plant Area Index from Phase-Shift Terrestrial Laser Scans

    Directory of Open Access Journals (Sweden)

    Pyare Pueschel

    2014-03-01

    Full Text Available The characterization of canopy structure is crucial for modeling eco-physiological processes. Two commonly used metrics for characterizing canopy structure are the gap fraction and the effective Plant Area Index (PAIe. Both have been successfully retrieved with terrestrial laser scanning. However, a systematic assessment of the influence of the laser scan properties on the retrieval of these metrics is still lacking. This study investigated the effects of resolution, measurement speed, and noise compression on the retrieval of gap fraction and PAIe from phase-shift FARO Photon 120 laser scans. We demonstrate that FARO’s noise compression yields gap fractions and PAIe that deviate significantly from those based on scans without noise compression and strongly overestimate Leaf Area Index (LAI estimates based on litter trap measurements. Scan resolution and measurement speed were also shown to impact gap fraction and PAIe, but this depended on leaf development phase, stand structure, and LAI calculation method. Nevertheless, PAIe estimates based on various scan parameter combinations without noise compression proved to be quite stable.

  10. Characterisation of estuarine intertidal macroalgae by laser-induced fluorescence

    DEFF Research Database (Denmark)

    Gameiro, Carla; Utkin, Andrei B.; Sousa Dias Cartaxana, Paulo Jorge

    2015-01-01

    . Three bands characterised the LIF spectra of red macroalgae with emission maxima in the ranges 577-583 nm, 621-642 nm and 705-731 nm. Green and brown macroalgae showed one emission maximum in the red region (687-690 nm) and/or one in the far-red region (726-732 nm). Characteristics of LIF emission...... spectra were determined by differences in the main fluorescing pigments: phycoerythrin, phycocyanin and chlorophyll a (Chl a). In the green and brown macroalgae groups, the relative significance of the two emission maxima seems to be related to the thickness of the photosynthetic layer. In thick...... macroalgae, like Codium tomentosum or Fucus vesiculosus, the contribution of the far-red emission fluorescence peak was more significant, most probably due to re-absorption of the emitted red Chl a fluorescence within the dense photosynthetic layer. Similarly, an increase in the number of layers of the thin...

  11. Laser scanning of a recirculation zone on the Bolund escarpment

    DEFF Research Database (Denmark)

    Mann, Jakob; Angelou, Nikolas; Sjöholm, Mikael

    2014-01-01

    . The instrument measures the line-of-sight velocity 390 times per second and scans ten wind profiles from the ground up to seven meters per second. We observe a sharp interface between slow and fast moving fluid after the escarpment, and the interface is moving rapidly up and down. This implies that the position...... of the maximum velocity standard deviation is elevated a few meters above the surface. Close to the ground the mean wind is reversed relative to the general flow. The results are used to test computational fluid dynamics models for flow over terrain, and has relevance for wind energy. The preliminary comparison...... shows that the models are incapable of reproducing the reversed flow close to the surface, but more works needs to be done....

  12. Topographic laser ranging and scanning principles and processing

    CERN Document Server

    Shan, Jie

    2008-01-01

    A systematic, in-depth introduction to theories and principles of Light Detection and Ranging (LiDAR) technology is long overdue, as it is the most important geospatial data acquisition technology to be introduced in recent years. An advanced discussion, this text fills the void.Professionals in fields ranging from geology, geography and geoinformatics to physics, transportation, and law enforcement will benefit from this comprehensive discussion of topographic LiDAR principles, systems, data acquisition, and data processing techniques. The book covers ranging and scanning fundamentals, and broad, contemporary analysis of airborne LiDAR systems, as well as those situated on land and in space. The authors present data collection at the signal level in terms of waveforms and their properties; at the system level with regard to calibration and georeferencing; and at the data level to discuss error budget, quality control, and data organization. They devote the bulk of the book to LiDAR data processing and inform...

  13. Geodetic Imaging of Marsh Surface Elevation with Terrestrial Laser Scanning

    Science.gov (United States)

    Nguyen, C. T.; Starek, M. J.; Gibeaut, J. C.; Lord, A.

    2015-12-01

    The resilience of marshes to a rising sea is dependent on their elevation response. Given the level of precision required to measure minute changes in marsh elevation over time, survey methods have to be adapted to minimize impacts to the sediment surface. Current approaches include Surface Elevation Tables (SETs), which are used to monitor wetland surface change with respect to an in situ vertical benchmark. Although SETs have been proven as an effective technique to track subtle sedimentation rates (RTK GPS for comparison. Grand Bay in Mississippi USA is one of the most biologically productive estuarine ecosystems in the Gulf of Mexico. The study region is covered by dense and tall saw-grass that makes it a challenging environment for bare-earth mapping. For this survey, a Riegl VZ-400 TLS (1550 nm wavelength) was utilized. The system is capable of recording multiple returns per a transmitted pulse (up to 15) and provides full-waveform output for signal post-processing to extract returns. The objectives of the study are twofold: 1) examine impacts of TLS survey design, scan angle and scan density on marsh elevation mapping; 2) assess the capabilities of multiple-echo and full-waveform TLS data to extract the bare-earth surface below the dense vegetation. This presentation will present results of the study including the developed TLS survey protocol and data processing workflow, details on waveform and multi-echo approaches for ground point detection, and a discussion on error analysis and challenges for measuring marsh surface elevation with TLS.

  14. Fluorescence line-narrowing studies of Nd:glass laser materials

    International Nuclear Information System (INIS)

    Riseberg, L.A.; Brecher, C.

    The increasing importance of Nd glass lasers in laser fusion technology has emphasized the inadequacy in the understanding of the optical properties of rare earth ions in glasses. Indeed, it has been difficult to generate models for the performance of these devices, and the selection of host glasses could be done by little more than a trial-and-error approach. The technique of laser-induced fluorescence line-narrowing developed within the last few years provides a new and powerful tool for the study of these systems. In this technique, a laser excites within the inhomogeneously broadened absorption bands a selected subgroup of the ions in the system, namely those whose absorption energy is resonant with the laser. If the excitation does not migrate among the entire collection of ions prior to fluorescence, the fluorescence that is observed is only from the group that was excited and is narrowed. This permits the selective study of classes of ion sites within the ensemble. The concept is indicated schematically. By the use of a tunable laser, such as a dye laser, it is possible to vary the class of sites, defined by energy, that is excited and thereby study the important spectroscopic properties and their variations, unclouded by the averaging that occurs under excitation of the entire system. Furthermore, it is then possible to use the spectroscopic information to infer a description of the variation of the microscopic environment, and a rationalization of the effects of compositional changes. Use of a pulsed dye laser and time-resolved detection permits the study of the dynamics, including, for example, the energy transfer among ions of different energies within the inhomogeneously-broadened spectrum. The goal of this project has been to apply such studies to glasses of interest to glass laser technology, providing information for device modeling, and establishing design criteria for glass selection

  15. Fan-beam scanning laser optical computed tomography for large volume dosimetry

    Science.gov (United States)

    Dekker, K. H.; Battista, J. J.; Jordan, K. J.

    2017-05-01

    A prototype scanning-laser fan beam optical CT scanner is reported which is capable of high resolution, large volume dosimetry with reasonable scan time. An acylindrical, asymmetric aquarium design is presented which serves to 1) generate parallel-beam scan geometry, 2) focus light towards a small acceptance angle detector, and 3) avoid interference fringe-related artifacts. Preliminary experiments with uniform solution phantoms (11 and 15 cm diameter) and finger phantoms (13.5 mm diameter FEP tubing) demonstrate that the design allows accurate optical CT imaging, with optical CT measurements agreeing within 3% of independent Beer-Lambert law calculations.

  16. Combined nonlinear laser imaging (two-photon excitation fluorescence, second and third-harmonic generation, and fluorescence lifetime imaging microscopies) in ovarian tumors

    Science.gov (United States)

    Adur, J.; Pelegati, V. B.; de Thomaz, A. A.; Bottcher-Luiz, F.; Andrade, L. A. L. A.; Almeida, D. B.; Carvalho, H. F.; Cesar, C. L.

    2012-03-01

    We applied Two-photon Excited Fluorescence (TPEF), Second/Third Harmonic Generation (SHG and THG) and Fluorescence Lifetime Imaging (FLIM) Non Linear Optics (NLO) Laser-Scanning Microscopy within the same imaging platform to evaluate their use as a diagnostic tool in ovarian tumors. We assess of applicability of this multimodal approach to perform a pathological evaluation of serous and mucinous tumors in human samples. The combination of TPEF-SHG-THG imaging provided complementary information about the interface epithelium/stromal, such as the transformation of epithelium surface (THG) and the overall fibrillar tissue architecture (SHG). The fact that H&E staining is the standard method used in clinical pathology and that the stored samples are usually fixed makes it important a re-evaluation of these samples with NLO microscopy to compare new results with a library of already existing samples. FLIM, however, depends on the chemical environment around the fluorophors that was completely changed after fixation; therefore it only makes sense in unstained samples. Our FLIM results in unstained samples demonstrate that it is possible to discriminate healthy epithelia from serous or mucinous epithelia. Qualitative and quantitative analysis of the different imaging modalities used showed that multimodal nonlinear microscopy has the potential to differentiate between cancerous and healthy ovarian tissue.

  17. Glacier Snowline Determination from Terrestrial Laser Scanning Intensity Data

    Directory of Open Access Journals (Sweden)

    Hannah Prantl

    2017-07-01

    Full Text Available Accurately identifying the extent of surface snow cover on glaciers is important for extrapolating end of year mass balance measurements, constraining the glacier surface radiative energy balance and evaluating model simulations of snow cover. Here, we use auxiliary information from Riegl VZ-6000 Terrestrial Laser Scanner (TLS return signals to accurately map the snow cover over a glacier throughout an ablation season. Three classification systems were compared, and we find that supervised classification based on TLS signal intensity alone is outperformed by a rule-based classification employing intensity, surface roughness and an associated optical image, which achieves classification accuracy of 68–100%. The TLS intensity signal shows no meaningful relationship with surface or bulk snow density. Finally, we have also compared our Snow Line Altitude (SLA derived from TLS with SLA derived from the model output, as well as one Landsat image. The results of the model output track the SLA from TLS well, however with a positive bias. In contrast, automatic Landsat-derived SLA slightly underestimates the SLA from TLS. To conclude, we demonstrate that the snow cover extent can be mapped successfully using TLS, although the snow mass remains elusive.

  18. Decoupling Electronic versus Nuclear Photoresponse of Isolated Green Fluorescent Protein Chromophores Using Short Laser Pulses

    Science.gov (United States)

    Kiefer, Hjalte V.; Pedersen, Henrik B.; Bochenkova, Anastasia V.; Andersen, Lars H.

    2016-12-01

    The photophysics of a deprotonated model chromophore for the green fluorescent protein is studied by femtosecond laser pulses in an electrostatic ion-storage ring. The laser-pulse duration is much shorter than the time for internal conversion, and, hence, contributions from sequential multiphoton absorption, typically encountered with ns-laser pulses, are avoided. Following single-photon excitation, the action-absorption maximum is shown to be shifted within the S0 to S1 band from its origin at about 490 to 450 nm, which is explained by the different photophysics involved in the detected action.

  19. a Study about Terrestrial Laser Scanning for Reconstruction of Precast Concrete to Support Qlassic Assessment

    Science.gov (United States)

    Aziz, M. A.; Idris, K. M.; Majid, Z.; Ariff, M. F. M.; Yusoff, A. R.; Luh, L. C.; Abbas, M. A.; Chong, A. K.

    2016-09-01

    Nowadays, terrestrial laser scanning shows the potential to improve construction productivity by measuring the objects changes using real-time applications. This paper presents the process of implementation of an efficient framework for precast concrete using terrestrial laser scanning that enables contractors to acquire accurate data and support Quality Assessment System in Construction (QLASSIC). Leica Scanstation C10, black/white target, Autodesk Revit and Cyclone software were used in this study. The results were compared with the dimensional of based model precast concrete given by the company as a reference with the AutoDesk Revit model from the terrestrial laser scanning data and conventional method (measuring tape). To support QLASSIC, the tolerance dimensions of cast in-situ & precast elements is +10mm / -5mm. The results showed that the root mean square error for a Revit model is 2.972mm while using measuring tape is 13.687mm. The accuracy showed that terrestrial laser scanning has an advantage in construction jobs to support QLASSIC.

  20. A STUDY ABOUT TERRESTRIAL LASER SCANNING FOR RECONSTRUCTION OF PRECAST CONCRETE TO SUPPORT QLASSIC ASSESSMENT

    Directory of Open Access Journals (Sweden)

    M. A. Aziz

    2016-09-01

    Full Text Available Nowadays, terrestrial laser scanning shows the potential to improve construction productivity by measuring the objects changes using real-time applications. This paper presents the process of implementation of an efficient framework for precast concrete using terrestrial laser scanning that enables contractors to acquire accurate data and support Quality Assessment System in Construction (QLASSIC. Leica Scanstation C10, black/white target, Autodesk Revit and Cyclone software were used in this study. The results were compared with the dimensional of based model precast concrete given by the company as a reference with the AutoDesk Revit model from the terrestrial laser scanning data and conventional method (measuring tape. To support QLASSIC, the tolerance dimensions of cast in-situ & precast elements is +10mm / -5mm. The results showed that the root mean square error for a Revit model is 2.972mm while using measuring tape is 13.687mm. The accuracy showed that terrestrial laser scanning has an advantage in construction jobs to support QLASSIC.

  1. Congenital optic tract syndrome: magnetic resonance imaging and scanning laser ophthalmoscopy findings.

    Science.gov (United States)

    Murphy, M A; Grosof, D H; Hart, W M

    1997-12-01

    Lesions of the optic tract produce a distinctive pattern of optic atrophy and visual field loss and may be due to either congenital or acquired causes. We report a case of a congenital optic tract syndrome and correlate the magnetic resonance imaging findings with the appearance of nerve fiber layer defects found by confocal scanning laser ophthalmoscopy.

  2. Laser Scanning Technology as Part of a Comprehensive Condition Assessment for Covered Bridges

    Science.gov (United States)

    Brian K. Brashaw; Samuel Anderson; Robert J. Ross

    2015-01-01

    New noncontact technologies have been developed and implemented for determining as-built condition and current dimensions for a wide variety of objects and buildings. In this study, a three-dimensional laser scanner was used to determine the dimensions and visual condition of a historic bridge in the Amnicon Falls State Park in northern Wisconsin. 3D scanning provides...

  3. THE APPLICATION OF 3D LASER SCANNING IN THE PROTECTION OF GROTTOES AND CARVINGS IN CHINA

    Directory of Open Access Journals (Sweden)

    L. Yumin

    2013-07-01

    Full Text Available With the development of 3D laser scanning technology, it has been widely used in the recording and conservation of stone cultural relics. A lot of grottoes and carvings in national key cultural heritage protection units in Shanxi, Gansu and Sichuan areas of China have been scanned by 3D laser scanner in their protection projects. In this paper, via these 3D laser scanning projects of the grottoes and carvings, technical essentials of indoor and field work in the 3D laser scanning technology of stone cultural relics are summarized. At the same time, different devices were selected and different device parameters were set on the basis of characteristics of specific relics. Thus the current situation of the relic was recorded precisely with the least storage space and the shortest working time. At last, digital results including 3D models, 2D drawings, the videos for exhibition and etc with powerful operability which meet different needs are obtained based on the original point cloud. This paper can provide some beneficial reference and experience for recording and conservation of the grottoes and carvings relics in the future.

  4. Confocal scanning laser microscopic study of the RDX defect structure in deformed polymer-bonded explosives

    NARCIS (Netherlands)

    Heijden, A.E.D.M. van der; Bouma, R.H.B.

    2016-01-01

    The influence of an explosion-driven deformation on the defect structure in RDX crystals embedded in a polymer-bonded explosive was investigated by means of confocal scanning laser microscopy. The images were compared to the defect structure in the as-received RDX grades, embedded

  5. The Application of 3d Laser Scanning in the Protection of Grottoes and Carvings in China

    Science.gov (United States)

    Yumin, L.; Rong, Z.; Yu, Z.

    2013-07-01

    With the development of 3D laser scanning technology, it has been widely used in the recording and conservation of stone cultural relics. A lot of grottoes and carvings in national key cultural heritage protection units in Shanxi, Gansu and Sichuan areas of China have been scanned by 3D laser scanner in their protection projects. In this paper, via these 3D laser scanning projects of the grottoes and carvings, technical essentials of indoor and field work in the 3D laser scanning technology of stone cultural relics are summarized. At the same time, different devices were selected and different device parameters were set on the basis of characteristics of specific relics. Thus the current situation of the relic was recorded precisely with the least storage space and the shortest working time. At last, digital results including 3D models, 2D drawings, the videos for exhibition and etc with powerful operability which meet different needs are obtained based on the original point cloud. This paper can provide some beneficial reference and experience for recording and conservation of the grottoes and carvings relics in the future.

  6. Application of 3D Laser Scanning Technology in Complex Rock Foundation Design

    Science.gov (United States)

    Junjie, Ma; Dan, Lu; Zhilong, Liu

    2017-12-01

    Taking the complex landform of Tanxi Mountain Landscape Bridge as an example, the application of 3D laser scanning technology in the mapping of complex rock foundations is studied in this paper. A set of 3D laser scanning technologies are formed and several key engineering problems are solved. The first is 3D laser scanning technology of complex landforms. 3D laser scanning technology is used to obtain a complete 3D point cloud data model of the complex landform. The detailed and accurate results of the surveying and mapping decrease the measuring time and supplementary measuring times. The second is 3D collaborative modeling of the complex landform. A 3D model of the complex landform is established based on the 3D point cloud data model. The super-structural foundation model is introduced for 3D collaborative design. The optimal design plan is selected and the construction progress is accelerated. And the last is finite-element analysis technology of the complex landform foundation. A 3D model of the complex landform is introduced into ANSYS for building a finite element model to calculate anti-slide stability of the rock, and provides a basis for the landform foundation design and construction.

  7. Better Visualisation of Air-borne Laser Scanning for geomorphological and archaeological interpretation

    DEFF Research Database (Denmark)

    Ljungberg, Thomas; Scott, D; Kristiansen, Søren Munch

    Digital elevation models derived from high-precision Air-borne Laser Scanning (ALS or LiDAR) point clouds are becoming increasingly available throughout the world. These elevation models presents a very valuable tool for locating and interpreting geomorphological as well as archaeological feature...

  8. INITIAL TESTS AND ACCURACY ASSESMENT OF A COMPACT MOBILE LASER SCANNING SYSTEM

    Directory of Open Access Journals (Sweden)

    K. Julge

    2016-06-01

    Full Text Available Mobile laser scanning (MLS is a faster and cost-effective alternative to static laser scanning, even though there is a slight trade-off in accuracy. This contribution describes a compact mobile laser scanning system mounted on a vehicle. The technical parameters of the used system components, i.e. a small LIDAR sensor Velodyne VLP-16 and a dual antenna GNSS/INS system Advanced Navigation Spatial Dual, are reviewed, along with the integration of these components for spatial data acquisition. Calculation principles of 3D coordinates from the real-time data of all the involved sensors are discussed. The field tests were carried out in a controlled environment of a parking lot and at different velocities. Experiments were carried out to test the ability of the GNSS/INS system to cope with difficult conditions, e.g. sudden movements due to cornering or swerving. The accuracy of the resulting MLS point cloud is evaluated with respect to high-accuracy static terrestrial laser scanning data. Problems regarding combining LIDAR, GNSS and INS sensors are outlined, as well as the initial accuracy assessments. Initial tests revealed errors related to insufficient quality of inertial data and a need for the trajectory post-processing calculations. Although this study was carried out while the system was mounted on a car, there is potential for operating the system on an unmanned aerial vehicle, all-terrain vehicle or in a backpack mode due to its relatively compact size.

  9. Initial Tests and Accuracy Assesment of a Compact Mobile Laser Scanning System

    Science.gov (United States)

    Julge, K.; Ellmann, A.; Vajakas, T.; Kolka, R.

    2016-06-01

    Mobile laser scanning (MLS) is a faster and cost-effective alternative to static laser scanning, even though there is a slight trade-off in accuracy. This contribution describes a compact mobile laser scanning system mounted on a vehicle. The technical parameters of the used system components, i.e. a small LIDAR sensor Velodyne VLP-16 and a dual antenna GNSS/INS system Advanced Navigation Spatial Dual, are reviewed, along with the integration of these components for spatial data acquisition. Calculation principles of 3D coordinates from the real-time data of all the involved sensors are discussed. The field tests were carried out in a controlled environment of a parking lot and at different velocities. Experiments were carried out to test the ability of the GNSS/INS system to cope with difficult conditions, e.g. sudden movements due to cornering or swerving. The accuracy of the resulting MLS point cloud is evaluated with respect to high-accuracy static terrestrial laser scanning data. Problems regarding combining LIDAR, GNSS and INS sensors are outlined, as well as the initial accuracy assessments. Initial tests revealed errors related to insufficient quality of inertial data and a need for the trajectory post-processing calculations. Although this study was carried out while the system was mounted on a car, there is potential for operating the system on an unmanned aerial vehicle, all-terrain vehicle or in a backpack mode due to its relatively compact size.

  10. Nondestructive estimates of above-ground biomass using terrestrial laser scanning

    NARCIS (Netherlands)

    Calders, K.; Newnham, G.; Burt, A.; Murphy, S.; Raumonen, P.; Herold, M.; Culvenor, D.; Avitabile, V.; Disney, M.; Armston, J.; Kaasalainen, M.

    2015-01-01

    Allometric equations are currently used to estimate above-ground biomass (AGB) based on the indirect relationship with tree parameters. Terrestrial laser scanning (TLS) can measure the canopy structure in 3D with high detail. In this study, we develop an approach to estimate AGB from TLS data, which

  11. Morphological changes along a dike landside slope sampled by 4D high resolution terrestrial laser scanning

    NARCIS (Netherlands)

    Herrero Huerta, M.; Lindenbergh, R.C.; Ponsioen, Luc; van Damme, M.

    2016-01-01

    Emergence of light detection and ranging (LiDAR) technology provides new tools for geomorphologic studies improving spatial and temporal resolution of data sampling hydrogeological instability phenomena. Specifically, terrestrial laser scanning (TLS) collects high resolution 3D point clouds

  12. Modeling of scanning laser polarimetry images of the human retina for progression detection of glaucoma

    NARCIS (Netherlands)

    Vermeer, Koen A.; Vos, Frans M.; Lo, Barrick; Zhou, Qienyuan; Lemij, Hans G.; Vossepoel, Albert M.; van Vliet, Lucas J.

    2006-01-01

    The development of methods to detect slowly progressing diseases is often hampered by the time-consuming acquisition of a sufficiently large data set. In this paper, a method is presented to model the change in images acquired by scanning laser polarimetry, for the detection of glaucomatous

  13. Imaging inclusion complex formation in starch granules using confocal laser scanning microscopy

    NARCIS (Netherlands)

    Manca, Marianna; Woortman, Albert J. J.; Loos, Katja; Loi, Maria A.

    The tendency of amylose to form inclusion complexes with guest molecules has been an object of wide interest due to its fundamental role in food processing. Here we investigated the features of starch granules from several botanical sources using confocal laser scanning microscopy (CLSM) and

  14. Boosting the predictive accuracy of urban hedonic house price models through airborne laser scanning

    NARCIS (Netherlands)

    Helbich, M.; Jochem, A.; Mücke, W.; Höfle, B.

    This paper introduces an integrative approach to hedonic house price modeling which utilizes high density 3D airborne laser scanning (ALS) data. In general, it is shown that extracting exploratory variables using 3D analysis – thus explicitly considering high-rise buildings, shadowing effects, etc.

  15. Multi-objective optimization of cellular scanning strategy in selective laser melting

    DEFF Research Database (Denmark)

    Ahrari, Ali; Deb, Kalyanmoy; Mohanty, Sankhya

    2017-01-01

    The scanning strategy for selective laser melting - an additive manufacturing process - determines the temperature fields during the manufacturing process, which in turn affects residual stresses and distortions, two of the main sources of process-induced defects. The goal of this study...

  16. Dynamic experimentation on the confocal laser scanning microscope : application to soft-solid, composite food materials

    NARCIS (Netherlands)

    Plucknett, K.P.; Pomfret, S.J.; Normand, V.; Ferdinando, D.; Veerman, C.; Frith, W.J.; Norton, I.T.

    2001-01-01

    Confocal laser scanning microscopy (CLSM) is used to follow the dynamic structural evolution of several phase-separated mixed biopolymer gel composites. Two protein/polysaccharide mixed gel systems were examined: gelatin/maltodextrin and gelatin/agarose. These materials exhibit 'emulsion-like'

  17. An evaluation of the efficiency of laser scanning technology in the ...

    African Journals Online (AJOL)

    Green-Blue (RGB) intensity values for each point. Point clouds of data can now be imported into a CAD package and compared to design specifications. In the case where “as-built” specifications differ for the initial design, laser scanning allows ...

  18. Flash scanning the CO2 laser: a revival of the CO2 laser in plastic surgery

    Science.gov (United States)

    Lach, Elliot

    1994-09-01

    The CO2 laser has broad clinical application yet also presents a number of practical disadvantages. These drawbacks have limited the success and utilization of this laser in plastic surgery. Flashscanner technology has recently been used for char-free CO2 laser surgery of the oropharynx, the external female genital tract, and perirectal mucosa. A commercially available optomechanical flashscanner unit `Swiftlase,' was adapted to a CO2 laser and used for treatment in numerous plastic surgical applications. Conditions and situations that were treated in this study included generalized neurofibromatosis, tuberous sclerosis, rhinophyma, viral warts, breast reconstruction, and deepithelialization prior to microsurgery or local flap transfer and/or skin graft placement. There were no significant wound healing complications. Some patients previously sustained undue scarring from conventional CO2 laser surgery. Conservative, primarily ablative CO2 laser surgery with the Swiftlase has usefulness for treatment of patients in plastic surgery including those that were previously unsuccessfully treated.

  19. ANALYSIS OF TERRESTRIAL LASER SCANNING AND PHOTOGRAMMETRY DATA FOR DOCUMENTATION OF HISTORICAL ARTIFACTS

    Directory of Open Access Journals (Sweden)

    R. A. Kuçak

    2016-10-01

    Full Text Available Historical artifacts living from the past until today exposed to many destructions non-naturally or naturally. For this reason, The protection and documentation studies of Cultural Heritage to inform the next generations are accelerating day by day in the whole world. The preservation of historical artifacts using advanced 3D measurement technologies becomes an efficient tool for mapping solutions. There are many methods for documentation and restoration of historic structures. In addition to traditional methods such as simple hand measurement and tachometry, terrestrial laser scanning is rapidly becoming one of the most commonly used techniques due to its completeness, accuracy and fastness characteristics. This study evaluates terrestrial laser scanning(TLS technology and photogrammetry for documenting the historical artifacts facade data in 3D Environment. PhotoModeler software developed by Eos System was preferred for Photogrammetric method. Leica HDS 6000 laser scanner developed by Leica Geosystems and Cyclone software which is the laser data evaluation software belonging to the company is preferred for Terrestrial Laser Scanning method. Taking into account the results obtained with this software product is intended to provide a contribution to the studies for the documentation of cultural heritage.

  20. Multimodal scanning laser ophthalmoscopy for image guided treatment of age-related macular degeneration

    Science.gov (United States)

    Hammer, Daniel X.; Ferguson, R. D.; Patel, Ankit H.; Iftimia, Nicusor V.; Mujat, Mircea; Husain, Deeba

    2009-02-01

    Subretinal neovascular membranes (SRNM) are a deleterious complication of laser eye injury and retinal diseases such as age-related macular degeneration (AMD), choroiditis, and myopic retinopathy. Photodynamic therapy (PDT) and anti-vascular endothelial growth factor (VEGF) drugs are approved treatment methods. PDT acts by selective dye accumulation, activation by laser light, and disruption and clotting of the new leaky vessels. However, PDT surgery is currently not image-guided, nor does it proceed in an efficient or automated manner. This may contribute to the high rate of re-treatment. We have developed a multimodal scanning laser ophthalmoscope (SLO) for automated diagnosis and image-guided treatment of SRNMs associated with AMD. The system combines line scanning laser ophthalmoscopy (LSLO), fluorescein angiography (FA), indocyanine green angiography (ICGA), PDT laser delivery, and retinal tracking in a compact, efficient platform. This paper describes the system hardware and software design, performance characterization, and automated patient imaging and treatment session procedures and algorithms. Also, we present initial imaging and tracking measurements on normal subjects and automated lesion demarcation and sizing analysis of previously acquired angiograms. Future pre-clinical testing includes line scanning angiography and PDT treatment of AMD subjects. The automated acquisition procedure, enhanced and expedited data post-processing, and innovative image visualization and interpretation tools provided by the multimodal retinal imager may eventually aid in the diagnosis, treatment, and prognosis of AMD and other retinal diseases.

  1. Rapid, k-space linear wavelength scanning laser source based on recirculating frequency shifter.

    Science.gov (United States)

    Wan, Minggui; Wang, Lin; Li, Feng; Cao, Yuan; Wang, Xudong; Feng, Xinhuan; Guan, Bai-Ou; Wai, P K A

    2016-11-28

    We propose and successfully demonstrate a k-space linear and self-clocked wavelength scanning fiber laser source based on recirculating frequency shifting (RFS). The RFS is realized with a high speed electro-optic dual parallel Mach-Zehnder modulator operating at the state of carrier suppressed single sideband modulation. A gated short pulse is injected into an amplified RFS loop to generate the wavelength scanning pulse train. We find that the accumulation of in-band amplified spontaneous emission (ASE) noise over multiple scanning periods will saturate the erbium-doped fiber amplifier and impede the amplification to the pulse signal in the RFS loop. To overcome the degradation of temporal signal due to the accumulation of ASE noise over multiple scanning periods, we insert a modulated optical switch into the RFS loop to completely attenuate the in-band ASE noise at the end of each scanning period. The signal to noise ratio of the temporal pulsed signal is greatly enhanced. K-space linear and self-clocked wavelength scanning fiber laser sources in 6.1 nm/7.2 nm scanning range with 20 GHz/30 GHz frequency shifting are successfully demonstrated.

  2. Speciation of actinides in aqueous solution by time-resolved laser-induced fluorescence spectroscopy (TRLFS)

    International Nuclear Information System (INIS)

    Kimura, Takaumi; Kato, Yoshiharu; Meinrath, G.; Yoshida, Zenko; Choppin, G.R.

    1995-01-01

    Time-resolved laser-induced fluorescence spectroscopy (TRLFS) as a sensitive and selective method has been applied to the speciation of actinides in aqueous solution. Studies on hydrolysis and carbonate complexation of U(VI) and on determination of hydration number of Cm(III) are reported. (author)

  3. Determination of heavy metals in polar snow and ice by laser-excited atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Bolshov, M.A.; Boutron, C.F.

    1994-01-01

    The new laser-excited atomic fluorescence spectrometry technique offers unrivalled sensitivity for the determination of trace metals in a wide variety of samples. This has allowed the direct determination of Pb, Cd and Bi in Antarctic and Greenland snow and ice down to the sub pg/g level. (authors). 11 refs., 2 figs

  4. Laser capture microdissection of bacterial cells targeted by fluorescence in situ hybridization

    DEFF Research Database (Denmark)

    Schou, Kirstine Klitgaard; Mølbak, Lars; Jensen, Tim Kåre

    2005-01-01

    . By this method, a potentially pathogenic strain of the genus Brachyspira from formalin-fixed human colonic biopsies were visualized by fluorescence in situ hybridization (FISH) with a 16S rRNA-targeting oligonucleotide probe, followed by laser capture microdissection (LCM) of the targeted cells. Direct 16S r...

  5. Capillary electrophoresis with laser-induced fluorescence detection for fast and reliable apolipoprotein E genotyping

    NARCIS (Netherlands)

    Somsen, GW; Welten, HTME; Mulder, FP; Swart, CW; Kema, IP; de Jong, GJ

    2002-01-01

    The use of capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection for the rapid determination of apolipoprotein E (apoE) genotypes was studied. High resolution and sensitive detection of the concerned DNA restriction fragments was achieved using CE buffers with

  6. Formation of nitric oxide in an industrial burner measured by 2-D laser induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, A.; Bombach, R.; Kaeppeli, B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    We have performed two-dimensional Laser Induced Fluorescence (2-D LIF) measurements of nitric oxide and hydroxyl radical distributions in an industrial burner at atmospheric pressure. The relative 2-D LIF data of NO were set to an absolute scale by calibration with probe sampling combined with gas analysis. (author) 3 figs., 7 refs.

  7. Tritium Removal from Codeposits on Carbon Tiles by a Scanning Laser

    International Nuclear Information System (INIS)

    C.H. Skinner; C.A. Gentile; A. Carpe; G. Guttadora; S. Langish; K.M. Young; W.M. Shu; H. Nakamura

    2001-01-01

    A novel method for tritium release has been demonstrated on codeposited layers on graphite and carbon-fiber-composite tiles from the Tokamak Fusion Test Reactor (TFTR). A scanning continuous wave Nd laser beam heated the codeposits to a temperature of 1200-2300 degrees C for 10 to 200 milliseconds in an argon atmosphere. The temperature rise of the codeposit was significantly higher than that of the manufactured tile material (e.g., 1770 degrees C cf. 1080 degrees C). A major fraction of tritium was thermally desorbed with minimal change to the surface appearance at a laser intensity of 8 kW/cm(superscript ''2''), peak temperatures above 1230 degrees C and heating duration 10-20 milliseconds. In two experiments, 46% and 84% of the total tritium was released during the laser scan. The application of this method for tritium removal from a tokamak reactor appears promising and has significant advantages over oxidative techniques

  8. Forest Resource Measurements by Combination of Terrestrial Laser Scanning and Drone Use

    Science.gov (United States)

    Cheung, K.; Katoh, M.; Horisawa, M.

    2017-10-01

    Using terrestrial laser scanning (TLS), forest attributes such as diameter at breast height (DBH) and tree location can be measured accurately. However, due to low penetration of laser pulses to tree tops, tree height measurements are typically underestimated. In this study, data acquired by TLS and drones were combined; DBH and tree locations were determined by TLS, and tree heights were measured by drone use. The average tree height error and root mean square error (RMSE) of tree height were 0.8 and 1.2 m, respectively, for the combined method, and -0.4 and 1.7 m using TLS alone. The tree height difference was compared using airborne laser scanning (ALS). Furthermore, a method to acquire 100 % tree detection rate based on TLS data is suggested in this study.

  9. Maintaining a stationary laser footprint during angular scan in internal-reflection experiments.

    Science.gov (United States)

    Fontana, Eduardo; Cavalcanti, Gustavo Oliveira

    2013-11-10

    In internal-reflection metrology using prisms, the prism is usually mounted on a rotation/translation stage to enable adjusting angle and location of the laser footprint on the surface. If a visual inspection method is used to find the laser footprint, the task becomes impossible if invisible radiation in the near infrared is employed. In addition, it may be desirable to perform angular scan experiments with a stationary footprint on the surface during scans, or even to automatically probe specific points on an extended prism face for predetermined incidence angles. In this paper, a formulation is developed to determine the required translation along the prism face to allow maintaining the laser footprint stationary under a given rotation. A web-based app developed under the scope of this work demonstrates the applicability of the approach for silica, BK7 and SF2 glasses, in the wavelength range from 500 to 1500 nm and for an arbitrary geometry of the glass prism.

  10. Standalone Terrestrial Laser Scanning for Efficiently Capturing Aec Buildings for As-Built Bim

    Science.gov (United States)

    Bassier, M.; Vergauwen, M.; Van Genechten, B.

    2016-06-01

    With the increasing popularity of as-built building models for the architectural, engineering and construction (AEC) industry, the demand for highly accurate and dense point cloud data is rising. The current data acquisition methods are labour intensive and time consuming. In order to compete with indoor mobile mapping systems (IMMS), surveyors are now opting to use terrestrial laser scanning as a standalone solution. However, there is uncertainty about the accuracy of this approach. The emphasis of this paper is to determine the scope for which terrestrial laser scanners can be used without additional control. Multiple real life test cases are evaluated in order to identify the boundaries of this technique. Furthermore, this research presents a mathematical prediction model that provides an indication of the data accuracy given the project dimensions. This will enable surveyors to make informed discussions about the employability of terrestrial laser scanning without additional control in mid to large-scale projects.

  11. FOREST RESOURCE MEASUREMENTS BY COMBINATION OF TERRESTRIAL LASER SCANNING AND DRONE USE

    Directory of Open Access Journals (Sweden)

    K. Cheung

    2017-10-01

    Full Text Available Using terrestrial laser scanning (TLS, forest attributes such as diameter at breast height (DBH and tree location can be measured accurately. However, due to low penetration of laser pulses to tree tops, tree height measurements are typically underestimated. In this study, data acquired by TLS and drones were combined; DBH and tree locations were determined by TLS, and tree heights were measured by drone use. The average tree height error and root mean square error (RMSE of tree height were 0.8 and 1.2 m, respectively, for the combined method, and –0.4 and 1.7 m using TLS alone. The tree height difference was compared using airborne laser scanning (ALS. Furthermore, a method to acquire 100 % tree detection rate based on TLS data is suggested in this study.

  12. Accuracy of computer-guided implant surgery by a CAD/CAM and laser scanning technique.

    Science.gov (United States)

    Zhao, Xue Zhu; Xu, Wei Hua; Tang, Zhi Hui; Wu, Min Jie; Zhu, Jie; Chen, Si

    2014-01-01

    To explore the method of manufacturing an implant surgery template with a computer-aided design/computer-aided manufacturing (CAD/CAM) technique and evaluate its precision in clinical cases. Patients referred to the 2nd Dental Center of Peking University who were partially edentulous, were enrolled and scanned with cone beam computed tomography (CBCT). Diagnostic casts were laser scanned to record the configuration of the patients' dentition and mucosae. CBCT and laser scanning data were subsequently loaded into Simplant software. Implant positions were planned in the software with a computer-aided design technique, and surgical templates were fabricated with a rapid prototyping technique. These templates were used to guide implant placement surgery. The mean value of linear deviation was 1.00 mm (range 0 to 2.16 mm) for implant shoulder and 1.26 mm (range 0.51 to 2.86 mm) for the implant apex. The mean angular deviation was 4.74 degress (0.37 to 10.28 degrees). Deviations were higher in the posterior region than anterior. The tooth-supported template provided higher precision than did the tooth/ mucosa-supported template, but no statistically significant difference was found. Computer-guided implant surgery with the CAD/CAM technique provides dentists with a good platform for preoperative planning, precise implant insertion, and ideal rehabilitation. The protocol of this three-dimensional laser scanning technique can provide precision comparable to that of double-scanning.

  13. Terrestrial Laser Scanning Intensity Correction by Piecewise Fitting and Overlap-Driven Adjustment

    Directory of Open Access Journals (Sweden)

    Teng Xu

    2017-10-01

    Full Text Available Terrestrial laser scanning sensors deliver not only three-dimensional geometric information of the scanned objects but also the intensity data of returned laser pulse. Recent studies have demonstrated potential applications of intensity data from Terrestrial Laser Scanning (TLS. However, the distance and incident angle effects distort the TLS raw intensity data. To overcome the distortions, a new intensity correction method by combining the piecewise fitting and overlap-driven adjustment approaches was proposed in this study. The distance effect is eliminated by the piecewise fitting approach. The incident angle effect is eliminated by overlap-driven adjustment using the Oren–Nayar model that employs the surface roughness parameter of the scanned object. The surface roughness parameter at a certain point in an overlapped region of the multi-station scans is estimated by using the raw intensity data from two different stations at the point rather than estimated by averaging the surface roughness at other positions for each kind of object, which eliminates the estimation deviation. Experimental results obtained by using a TLS sensor (Riegl VZ-400i demonstrate that the proposed method is valid and the deviations of the retrieved reflectance values from those measured by a spectrometer are all less than 3%.

  14. Error analysis of motion correction method for laser scanning of moving objects

    Science.gov (United States)

    Goel, S.; Lohani, B.

    2014-05-01

    The limitation of conventional laser scanning methods is that the objects being scanned should be static. The need of scanning moving objects has resulted in the development of new methods capable of generating correct 3D geometry of moving objects. Limited literature is available showing development of very few methods capable of catering to the problem of object motion during scanning. All the existing methods utilize their own models or sensors. Any studies on error modelling or analysis of any of the motion correction methods are found to be lacking in literature. In this paper, we develop the error budget and present the analysis of one such `motion correction' method. This method assumes availability of position and orientation information of the moving object which in general can be obtained by installing a POS system on board or by use of some tracking devices. It then uses this information along with laser scanner data to apply correction to laser data, thus resulting in correct geometry despite the object being mobile during scanning. The major application of this method lie in the shipping industry to scan ships either moving or parked in the sea and to scan other objects like hot air balloons or aerostats. It is to be noted that the other methods of "motion correction" explained in literature can not be applied to scan the objects mentioned here making the chosen method quite unique. This paper presents some interesting insights in to the functioning of "motion correction" method as well as a detailed account of the behavior and variation of the error due to different sensor components alone and in combination with each other. The analysis can be used to obtain insights in to optimal utilization of available components for achieving the best results.

  15. Femtosecond laser irradiation of the fluorescent molecules-loaded poly(lactic-co-glycolic acid)

    Science.gov (United States)

    Umemoto, Taiga; Shibata, Akimichi; Terakawa, Mitsuhiro

    2017-09-01

    Molecular release from scaffolds is desired for tailoring cell-compatible tissue engineering. Several methods have been proposed to control molecular release, such as annealing, plasma treatment, and laser processing. In this study, we describe the alteration of Rhodamine B (RhB)-loaded poly(lactic-co-glycolic acid) (PLGA) after femtosecond laser irradiation, which was evaluated on the basis of the water absorption and mass remaining. Fluorescence measurement of released RhB molecules revealed the acceleration of the molecular release upon 400-nm laser irradiation, whereas 800-nm laser irradiation did not induce a comparable degree of change compared with non-irradiated samples. The result of the water absorption measurement indicates that the large amount of water absorption of 400-nm laser-irradiated PLGA sample may accelerate the diffusion of the loaded molecules through absorbing water, which resulted in the faster molecular release.

  16. Estimation of forest resources from a country wide laser scanning survey and national forest inventory data

    DEFF Research Database (Denmark)

    Nord-Larsen, Thomas; Schumacher, Johannes

    2012-01-01

    Airborne laser scanning may provide a means for assessing local forest biomass resources. In this study, national forest inventory (NFI) data was used as reference data for modeling forest basal area, volume, aboveground biomass, and total biomass from laser scanning data obtained in a countrywide...... scanning survey. Data covered a wide range of forest ecotypes, stand treatments, tree species, and tree species mixtures. The four forest characteristics were modeled using nonlinear regression and generalized method-of-moments estimation to avoid biased and inefficient estimates. The coefficient...... for deciduous forest and negatively biased for coniferous forest. Species type specific (coniferous, deciduous, or mixed forest) models reduced root mean squared error by 3–12% and removed the bias. In application, model predictions will be improved by stratification into deciduous and coniferous forest using e...

  17. Automated inspection of gaps on the free-form shape parts by laser scanning technologies

    Science.gov (United States)

    Zhou, Sen; Xu, Jian; Tao, Lei; An, Lu; Yu, Yan

    2018-01-01

    In industrial manufacturing processes, the dimensional inspection of the gaps on the free-form shape parts is critical and challenging, and is directly associated with subsequent assembly and terminal product quality. In this paper, a fast measuring method for automated gap inspection based on laser scanning technologies is presented. The proposed measuring method consists of three steps: firstly, the relative position is determined according to the geometric feature of measuring gap, which considers constraints existing in a laser scanning operation. Secondly, in order to acquire a complete gap profile, a fast and effective scanning path is designed. Finally, the range dimension of the gaps on the free-form shape parts including width, depth and flush, correspondingly, is described in a virtual environment. In the future, an appliance machine based on the proposed method will be developed for the on-line dimensional inspection of gaps on the automobile or aerospace production line.

  18. Detection of bacterial infection of agave plants by laser-induced fluorescence

    Science.gov (United States)

    Cervantes-Martinez, Jesus; Flores-Hernandez, Ricardo; Rodriguez-Garay, Benjamin; Santacruz-Ruvalcaba, Fernando

    2002-05-01

    Greenhouse-grown plants of Agave tequilana Weber var. azul were inoculated with Erwinia carotovora, the causal agent of stem soft rot. We investigated the laser-induced fluorescence (LIF) of agave plants to determine whether LIF can be used as a noninvasive sensing tool for pathological studies. The LIF technique was also investigated as a means of detecting the effect of the polyamine biosynthesis inhibitor beta-hydroxyethylhydrazine as a bactericide against the pathogenic bacterium Erwinia carotovora. A He-Ne laser at 632.8 nm was used as the excitation source, and in vivo fluorescence emission spectra were recorded in the 660-790-range. Fluorescence maxima were at 690 and 740 nm. The infected plants that were untreated with the bactericide showed a definite increase in fluorescence intensity at both maxima within the first three days after infection. Beginning on the fifth day, a steady decrease in fluorescence intensity was observed, with a greater effect at 740 than at 690 nm. After 30 days there was no fluorescence. The infected plants that had been treated with the bactericide showed no significant change in fluorescence compared with that of the uninfected plants. The ratio of fluorescence intensities was determined to be F 690 nm/F 740 nm for all treatments. These studies indicate that LIF measurements of agave plants may be used for the early detection of certain types of disease and for determining the effect of a bactericide on bacteria. The results also showed that fluorescence intensity ratios can be used as a reliable indicator of the progress of disease.

  19. A confocal scanning laser ophthalmoscope for retinal vessel oximetry

    Science.gov (United States)

    Lompado, Arthur

    Measurement of a person's blood oxygen saturation has long been recognized as a useful metric for the characterizing ailments ranging from chronic respiratory disorders to acute, potentially life threatening, traumas. The ubiquity of oxygen saturation monitors in the medical field, including portable pulse oximeters and laboratory based CO-oximeters, is a testament to the importance of this technique. The work presented here documents the design, fabrication and development of a unique type of oxygen saturation monitor, a confocal scanning retinal vessel oximeter, with the potential to expand the usefulness of the present devices. A large part of the knowledge base required to construct the instrument comes from the consideration of light scattering by red blood cells in a blood vessel. Therefore, a substantial portion of this work is devoted to the process of light scattering by whole human blood and its effects on the development of a more accurate oximeter. This light scattering effect has been both measured and modeled stochastically to determine its contribution to the measured oximeter signal. It is shown that, although well accepted in the published literature, the model only correlates marginally to the measurements due to inherent limitations imposed by the model assumptions. Nonetheless, enough material has been learned about the scattering to allow development of a mathematical model for the interaction of light with blood in a vessel, and this knowledge has been applied to the data reduction of the present oximeter. This data reduction technique has been tested in a controlled experiment employing a model eye with a blood filled mock retinal vessel. It will be shown that the presently developed technique exhibited strong correlation between the known blood oxygen saturation and that calculated by the new system.

  20. Laser-induced fluorescence imaging for monitoring nitrogen fertilizing treatments of wheat

    Science.gov (United States)

    Heisel, Francine; Sowinska, Malgorzata; Khalili, Elisabeth; Eckert, Caroline; Miehe, Joseph-Albert; Lichtenthaler, Hartmut K.

    1997-07-01

    The laser-induced fluorescence imaging system allows the recording of spectrally selected fluorescence images of the whole leaves or plants which is better and in contrast to the so far applied spot spectrofluorometer measurements. The fluorescence images of leaves of winter wheat (Soissons variety, Alsace) have been recorded at the four characteristic emission bands (440, 520, 690 and 740 nm) with a high resolution imaging device consisting of a frequency triplet or doubled Nd:YAG source for 355 nm or 532 nm excitation and of an intensified and gated CCD digitized camera. The effect of four different nitrogen treatments (0, 100, 140 and 180 kg/ha) on the fluorescence parameters (intensities F440, F520, F690, F740 and ratios F440/F520, F440/F690, F440/F740 and F690/F740) obtained by image processing has been analyzed by statistical treatment, in a randomized blocks experiment. The measurements have been carried out on two leaf storeys weekly gathered during two months (May and June 1996). For 355 nm excitation, a significant decrease of the fluorescence ratios F440/F690 and F440/F740 was observed for increasing nitrogen concentration: the blue and green mean fluorescence intensities remained much the same, while the red and far-red chlorophyll fluorescence emissions were enhanced by the fertilization. The fluorescence results are in excellent correlation with the crop yields.

  1. Ultratrace analysis of actinides via coprecipitation/laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Miller, S.M.

    1982-01-01

    Actinides were selectively preconcentrated by coprecipitating each out of solution with a fluoride matrix and calcining each sample at 800 0 C. The fluorescence spectrum of each sample was recorded by illuminating the sample with laser light and detecting fluorescence with either a fluorescence/Raman spectrometer, an infrared spectrometer or in certain cases a filter fluorimeter. Three previously unobserved actinide spectra were recorded. Narrow lines at 546.9 nm, 564.6 nm, and 569.6 nm were found for CaF 2 :PuO 2++ at 10K. CaF 2 :Am + 3 displayed two broadband fluorescent peaks at 625 nm and 746 nm at room temperature and CaF 2 :Pu + 3 possessed a fluorescent peak at 1.22 microns at 10K. Energy transfer was observed in the form of Tb fluorescence quenching in TbF 3 :Pu + 3 when Pu was present in quantities of 10 ppM or more and in the form of Tb fluorescence enhancement in TbF 3 :Am + 3 when 1 ppM or more of Am was present. Careful sample preparation and the use of temporal as well as a spectral discrimination system extended the detection limit of U from 1 ml samples to the subfemtogram level. The fluorescence detection limits for Pu and Am were extended to 0.48 and 0.032 pg/ml. 39 figures, 9 tables

  2. Instantaneous imaging of ozone in a gliding arc discharge using photofragmentation laser-induced fluorescence

    Science.gov (United States)

    Larsson, Kajsa; Hot, Dina; Gao, Jinlong; Kong, Chengdong; Li, Zhongshan; Aldén, Marcus; Bood, Joakim; Ehn, Andreas

    2018-04-01

    Ozone vapor, O3, is here visualized in a gliding arc discharge using photofragmentation laser-induced fluorescence. Ozone is imaged by first photodissociating the O3 molecule into an O radical and a vibrationally hot O2 fragment by a pump photon. Thereafter, the vibrationally excited O2 molecule absorbs a second (probe) photon that further transits the O2-molecule to an excited electronic state, and hence, fluorescence from the deexcitation process in the molecule can be detected. Both the photodissociation and excitation processes are achieved within one 248 nm KrF excimer laser pulse that is formed into a laser sheet and the fluorescence is imaged using an intensified CCD camera. The laser-induced signal in the vicinity of the plasma column formed by the gliding arc is confirmed to stem from O3 rather than plasma produced vibrationally hot O2. While both these products can be produced in plasmas a second laser pulse at 266 nm was utilized to separate the pump- from the probe-processes. Such arrangement allowed lifetime studies of vibrationally hot O2, which under these conditions were several orders of magnitude shorter than the lifetime of plasma-produced ozone.

  3. Fluorescence study of some xanthine dyes under stepped laser excitation

    International Nuclear Information System (INIS)

    Chirkova, L.V.; Ketsle, G.A.; Ermagambetov, K.T.

    1996-01-01

    Paper is devoted to definition of triplet state in molecules of xanthine dyes and study of intramolecular energy circulation. Stepped two-quanta excitation of dyes has been carried out with help of experimental unit. Intensive luminescence activated by excitation of triplet molecules of dyes within triplet-triplet band with wave length of 1060 nm was registered for eosin. Given luminescence spectrally coincides with fast fluorescence. 5 refs., 6 figs

  4. Selective fluorescence functionalization of dye-doped polymerized structures fabricated by direct laser writing (DLW) lithography

    Science.gov (United States)

    de Miguel, Gustavo; Vicidomini, Giuseppe; Duocastella, Martí; Diaspro, Alberto

    2015-11-01

    The continuous development of the vast arsenal of fabrication techniques is a pivotal factor in the breakthrough of nanotechnology. Although the broad interest is generally focused on the reduction of the dimensions of the fabricated structures, localized functionalization of the nanomaterials emerges as a key factor closely linked to their potential applications. In particular, fabrication of spatially selective fluorescence nanostructures is highly demanded in nanophotonics, as for example in three-dimensional (3D) optical data storage (ODS), where massive storage capacity and fast writing-reading processes are promised. We have developed an innovative method to control the location and intensity of the fluorescence signal in dye-doped photopolymerized structures fabricated with Direct Laser Writing (DLW) lithography. Well-defined fluorescent pixels (area = 0.24 μm2) were written inside a polymer matrix with the help of a femtosecond pulsed laser (multiphoton absorption) via a thermally-induced di-aggregation of a fluorescent dye. Moreover, we have accomplished a fine control of the fluorescence intensity which can increase the storage capacity of ODS systems fabricated with this approach.The continuous development of the vast arsenal of fabrication techniques is a pivotal factor in the breakthrough of nanotechnology. Although the broad interest is generally focused on the reduction of the dimensions of the fabricated structures, localized functionalization of the nanomaterials emerges as a key factor closely linked to their potential applications. In particular, fabrication of spatially selective fluorescence nanostructures is highly demanded in nanophotonics, as for example in three-dimensional (3D) optical data storage (ODS), where massive storage capacity and fast writing-reading processes are promised. We have developed an innovative method to control the location and intensity of the fluorescence signal in dye-doped photopolymerized structures fabricated

  5. An enhanced method for registration of dental surfaces partially scanned by a 3D dental laser scanning.

    Science.gov (United States)

    Park, Seongjin; Kang, Ho Chul; Lee, Jeongjin; Shin, Juneseuk; Shin, Yeong Gil

    2015-01-01

    In this paper, we propose the fast and accurate registration method of partially scanned dental surfaces in a 3D dental laser scanning. To overcome the multiple point correspondence problems of conventional surface registration methods, we propose the novel depth map-based registration method to register 3D surface models. First, we convert a partially scanned 3D dental surface into a 2D image by generating the 2D depth map image of the surface model by applying a 3D rigid transformation into this model. Then, the image-based registration method using 2D depth map images accurately estimates the initial transformation between two consequently acquired surface models. To further increase the computational efficiency, we decompose the 3D rigid transformation into out-of-plane (i.e. x-, y-rotation, and z-translation) and in-plane (i.e. x-, y-translation, and z-rotation) transformations. For the in-plane transformation, we accelerate the transformation process by transforming the 2D depth map image instead of transforming the 3D surface model. For the more accurate registration of 3D surface models, we enhance iterative closest point (ICP) method for the subsequent fine registration. Our initial depth map-based registration well aligns each surface model. Therefore, our subsequent ICP method can accurately register two surface models since it is highly probable that the closest point pairs are the exact corresponding point pairs. The experimental results demonstrated that our method accurately registered partially scanned dental surfaces. Regarding the computational performance, our method delivered about 1.5 times faster registration than the conventional method. Our method can be successfully applied to the accurate reconstruction of 3D dental objects for orthodontic and prosthodontic treatment. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  6. Wavelength scanning interferometry using a Ti:Sapphire laser with wide tuning range

    Science.gov (United States)

    Davila, A.; Huntley, J. M.; Pallikarakis, C.; Ruiz, P. D.; Coupland, J. M.

    2012-08-01

    Wavelength scanning interferometry in the visible or near-infra red is normally restricted to relatively narrow wavelength tuning ranges, which results in poor depth resolution compared to related techniques such as scanning white light interferometry. We describe how a commercially-available Ti:Sapphire laser with>100 nm scan range has been customized to allow high speed scans of several tens of thousands of frames at rates of up to 30 frames s-1, with variable exposure time to compensate for wavelength variation of laser power output and camera sensitivity. Mode hops and other nonlinearities in the scans, which prevent successful depth reconstructions by the standard approach of temporal Fourier transformation, are handled by measuring phase changes in the interferograms from a set of four wedges, and resampling the intensity signals on a uniformly-spaced vector of wavenumbers. With these changes, the depth-resolution is improved by a factor of more than 100x, and is found to approach the theoretical limit for scan ranges of up to 37 nm.

  7. Keypoint-based 4-Points Congruent Sets - Automated marker-less registration of laser scans

    Science.gov (United States)

    Theiler, Pascal Willy; Wegner, Jan Dirk; Schindler, Konrad

    2014-10-01

    We propose a method to automatically register two point clouds acquired with a terrestrial laser scanner without placing any markers in the scene. What makes this task challenging are the strongly varying point densities caused by the line-of-sight measurement principle, and the huge amount of data. The first property leads to low point densities in potential overlap areas with scans taken from different viewpoints while the latter calls for highly efficient methods in terms of runtime and memory requirements. A crucial yet largely unsolved step is the initial coarse alignment of two scans without any simplifying assumptions, that is, point clouds are given in arbitrary local coordinates and no knowledge about their relative orientation is available. Once coarse alignment has been solved, scans can easily be fine-registered with standard methods like least-squares surface or Iterative Closest Point matching. In order to drastically thin out the original point clouds while retaining characteristic features, we resort to extracting 3D keypoints. Such clouds of keypoints, which can be viewed as a sparse but nevertheless discriminative representation of the original scans, are then used as input to a very efficient matching method originally developed in computer graphics, called 4-Points Congruent Sets (4PCS) algorithm. We adapt the 4PCS matching approach to better suit the characteristics of laser scans. The resulting Keypoint-based 4-Points Congruent Sets (K-4PCS) method is extensively evaluated on challenging indoor and outdoor scans. Beyond the evaluation on real terrestrial laser scans, we also perform experiments with simulated indoor scenes, paying particular attention to the sensitivity of the approach with respect to highly symmetric scenes.

  8. Raster image correlation spectroscopy (RICS) for measuring fast protein dynamics and concentrations with a commercial laser scanning confocal microscope.

    Science.gov (United States)

    Brown, C M; Dalal, R B; Hebert, B; Digman, M A; Horwitz, A R; Gratton, E

    2008-01-01

    Raster image correlation spectroscopy (RICS) is a new and novel technique for measuring molecular dynamics and concentrations from fluorescence confocal images. The RICS technique extracts information about molecular dynamics and concentrations from images of living cells taken on commercial confocal systems. Here we develop guidelines for performing the RICS analysis on an analogue commercial laser scanning confocal microscope. Guidelines for typical instrument settings, image acquisition settings and analogue detector characterization are presented. Using appropriate instrument/acquisition parameters, diffusion coefficients and concentrations can be determined, even for highly dynamic dye molecules in solution. Standard curves presented herein demonstrate the ability to detect protein concentrations as low as approximately 2 nM. Additionally, cellular measurements give accurate values for the diffusion of paxillin-enhanced-green fluorescent protein (EGFP), an adhesion adaptor molecule, in the cytosol of the cell and also show slower paxillin dynamics near adhesions where paxillin interacts with immobile adhesion components. Methods are presented to account for bright immobile structures within the cell that dominate spatial correlation functions; allowing the extraction of fast protein dynamics within and near these structures. A running average algorithm is also presented to address slow cellular movement or movement of cellular features such as adhesions. Finally, methods to determine protein concentration in the presence of immobile structures within the cell are presented. A table is presented giving guidelines for instrument and imaging setting when performing RICS on the Olympus FV300 confocal and these guidelines are a starting point for performing the analysis on other commercial confocal systems.

  9. Early diagnosis of melanotic melanoma based on laser-induced melanin fluorescence

    Science.gov (United States)

    Eichhorn, Reinhold; Wessler, Gerd; Scholz, Matthias; Leupold, Dieter; Stankovic, Goran; Buder, Susanne; Stücker, Markus; Hoffmann, Klaus

    2009-05-01

    Because of the increasing incidence of skin cancer, interest in using the autofluorescence of skin tissue as a noninvasive tool for early diagnosis is enforced. Focus is especially on malignant melanotic melanoma. On the basis of a newly developed method to selectively excite melanin fluorescence of skin tissue by stepwise two-photon excitation with nanosecond laser pulses at 810 nm, we have investigated information from this melanin fluorescence with respect to the differentiation of pigmented lesions. A distinct difference in the melanin fluorescence spectrum of malignant melanoma (including melanoma in situ) when compared to that of benign melanocytic lesions (i.e., common nevi) has been found for freshly excised samples as well as for histopathological samples. There is also specific fluorescence from dysplastic nevi. In this way, early detection of malignant melanoma is possible.

  10. Laser-induced fluorescence imaging of acetone inside evaporating and burning fuel droplets

    Science.gov (United States)

    Shringi, D. S.; Shaw, B. D.; Dwyer, H. A.

    2009-01-01

    Laser-induced fluorescence was used to visualize acetone fields inside individual droplets of pure acetone as well as droplets composed of methanol or 1-propanol initially mixed with acetone. Droplets were supported on a horizontal wire and two vaporization conditions were investigated: (1) slow evaporation in room air and (2) droplet combustion, which leads to substantially faster droplet surface regression rates. Acetone was preferentially gasified, causing its concentration in droplets to drop in time with resultant decreases in acetone fluorescence intensities. Slowly vaporizing droplets did not exhibit large spatial variations of fluorescence within droplets, indicating that these droplets were relatively well mixed. Ignition of droplets led to significant variations in fluorescence intensities within droplets, indicating that these droplets were not well mixed. Ignited droplets composed of mixtures of 1-propanol and acetone showed large time-varying changes in shapes for higher acetone concentrations, suggesting that bubble formation was occurring in these droplets.

  11. Rilievo laser scanning a lunga distanza su frana mediante ILRIS LR

    Directory of Open Access Journals (Sweden)

    Arianna Pesci

    2012-04-01

    Full Text Available I sistemi laser a scansione terrestre caratterizzati da una lunga portata, cioè capaci di rilevare su  distanze  fino a 3 km, sono oggi sempre più utilizzati nel monitoraggio del territorio e nel controllo del dissesto o, in generale, delle variazioni morfologiche. Laser scanning survey of landslides by means of long distance ILRIS LRTerrestrial laser scanning (TLS is a remote sensing technique for high density acquisition of the physical surface of scanned, currently used in geologic surveys, engineering practice, cultural heritage, and mobile mapping. The very long range scanners, allow the acquisition from distances of the order of about 1  km  with  material  characterized  by  medium/high  reflecting properties.  At  present,  the  efforts  in  technological  advancements are highly aimed at the extension of maximum range, at the reduction of acquisition time, and so on. The ILRIS LR laser  scanner,  provided  by  Optech,  is  used  to  survey  a  very dense populated landslide area in the Tuscany Apennines, in the frame of a scientific experiment planned by INGV to test its performances.

  12. Rilievo laser scanning a lunga distanza su frana mediante ILRIS LR

    Directory of Open Access Journals (Sweden)

    Arianna Pesci

    2012-04-01

    Full Text Available I sistemi laser a scansione terrestre caratterizzati da una lunga portata, cioè capaci di rilevare su  distanze  fino a 3 km, sono oggi sempre più utilizzati nel monitoraggio del territorio e nel controllo del dissesto o, in generale, delle variazioni morfologiche.   Laser scanning survey of landslides by means of long distance ILRIS LR Terrestrial laser scanning (TLS is a remote sensing technique for high density acquisition of the physical surface of scanned, currently used in geologic surveys, engineering practice, cultural heritage, and mobile mapping. The very long range scanners, allow the acquisition from distances of the order of about 1  km  with  material  characterized  by  medium/high  reflecting properties.  At  present,  the  efforts  in  technological  advancements are highly aimed at the extension of maximum range, at the reduction of acquisition time, and so on. The ILRIS LR laser  scanner,  provided  by  Optech,  is  used  to  survey  a  very dense populated landslide area in the Tuscany Apennines, in the frame of a scientific experiment planned by INGV to test its performances.

  13. Kerosene detection using laser induced fluorescence imaging for aeronautical engines application; Detection du kerozene par imagerie de fluorescence induite par laser, pour application sur foyer aeronautique

    Energy Technology Data Exchange (ETDEWEB)

    Baranger, Ph.

    2004-10-15

    The new concepts of aeronautical engines, developed to follow the evolution of the European standards of pollution, are generally based on an improvement of the processes of liquid fuel injection and mixture in the combustion chamber. There is currently no model mature enough to work without experimental validation. The purpose of this thesis is to assess the possibility of measuring the kerosene (Jet A1) vapour distribution by PLIF (Planar Laser Induced Fluorescence). That measurement technique must quantitatively image the instantaneous concentrations fields of the vaporized fuel in a spray. The implementation of such a technique needs an experimental spectroscopic study, which was realized on the vapour of fuel. First of all, this study allowed us to determine the properties of the kerosene fluorescence spectrum versus physical parameters such as temperature, pressure or gas mixture composition, especially in presence of oxygen molecules. Then, it was shown that the fluorescence spectrum of the fuel could be reproduce in all physical conditions by a single mixture of four aromatics. Their photophysical properties were also analyzed. Following this spectroscopic study, a phenomenological model for the fluorescence of the gaseous fuel was set up. This model led us to a protocol for an optical diagnostic on this fuel vapour. An experiment was set up to test the implementation and the limits of this technique in simple laboratory conditions. This experiment confirmed that this is indeed a promising technique for the diagnostic of the fuel vapour in aeronautical engine. (author)

  14. Entropy-Based Registration of Point Clouds Using Terrestrial Laser Scanning and Smartphone GPS

    Directory of Open Access Journals (Sweden)

    Maolin Chen

    2017-01-01

    Full Text Available Automatic registration of terrestrial laser scanning point clouds is a crucial but unresolved topic that is of great interest in many domains. This study combines terrestrial laser scanner with a smartphone for the coarse registration of leveled point clouds with small roll and pitch angles and height differences, which is a novel sensor combination mode for terrestrial laser scanning. The approximate distance between two neighboring scan positions is firstly calculated with smartphone GPS coordinates. Then, 2D distribution entropy is used to measure the distribution coherence between the two scans and search for the optimal initial transformation parameters. To this end, we propose a method called Iterative Minimum Entropy (IME to correct initial transformation parameters based on two criteria: the difference between the average and minimum entropy and the deviation from the minimum entropy to the expected entropy. Finally, the presented method is evaluated using two data sets that contain tens of millions of points from panoramic and non-panoramic, vegetation-dominated and building-dominated cases and can achieve high accuracy and efficiency.

  15. Strategies of fluorescence staining for trace total ribonucleic acid analysis by capillary electrophoresis with argon ion laser-induced fluorescence.

    Science.gov (United States)

    Chung, Yi-An; Chen, Yi-Hsin; Chang, Po-Ling

    2015-08-01

    In this work, five fluorescent dyes (SYTO-9, SYBR Green I, SYBR Green II, SYBR Safe, and SYBR Gold) were used as both on-column and precolumn stains for total RNA analysis by CE-LIF with Ar ion laser excitation. In the on-column RNA stain, the SYTO-9 provided the highest fluorescence intensity and the lowest detectable concentration, as low as 10 pg/μL, while the SYBR Green II and SYBR Gold were adsorbed on the poly(ethylene oxide) thus affected the separation efficiency. As a precolumn stain, SYBR Gold was the most sensitive among the five dyes due to the strong affinity between the dye and RNA molecules. As a result, a single-cell quantity of RNA (10-30 pg per cell) could be detected by CE-LIF with precolumn staining by SYBR Gold. Because of the great savings of fluorescent dye using precolumn stain (one button dye may use for one million stain), this method is the best strategy for RNA staining in terms of cost-effectiveness and sensitivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Detection of proximal caries using quantitative light-induced fluorescence-digital and laser fluorescence: a comparative study.

    Science.gov (United States)

    Yoon, Hyung-In; Yoo, Min-Jeong; Park, Eun-Jin

    2017-12-01

    The purpose of this study was to evaluate the in vitro validity of quantitative light-induced fluorescence-digital (QLF-D) and laser fluorescence (DIAGNOdent) for assessing proximal caries in extracted premolars, using digital radiography as reference method. A total of 102 extracted premolars with similar lengths and shapes were used. A single operator conducted all the examinations using three different detection methods (bitewing radiography, QLF-D, and DIAGNOdent). The bitewing x-ray scale, QLF-D fluorescence loss (ΔF), and DIAGNOdent peak readings were compared and statistically analyzed. Each method showed an excellent reliability. The correlation coefficient between bitewing radiography and QLF-D, DIAGNOdent were -0.644 and 0.448, respectively, while the value between QLF-D and DIAGNOdent was -0.382. The kappa statistics for bitewing radiography and QLF-D had a higher diagnosis consensus than those for bitewing radiography and DIAGNOdent. The QLF-D was moderately to highly accurate (AUC = 0.753 - 0.908), while DIAGNOdent was moderately to less accurate (AUC = 0.622 - 0.784). All detection methods showed statistically significant correlation and high correlation between the bitewing radiography and QLF-D. QLF-D was found to be a valid and reliable alternative diagnostic method to digital bitewing radiography for in vitro detection of proximal caries.

  17. [Observation and analysis of microstructure of dentin caries lesions through 3D laser scanning microscope].

    Science.gov (United States)

    Lixia, Xu; Hongmei, Xu; Xiaoying, Zhu; Limei, Sun

    2016-10-01

    Microstructural changes in dentin carious lesions were investigated using a 3D laser scanning microscope, which has a morphological theoretical foundation in the further study of clinical caries disease prevention and treatments. Six fresh extracted caries molars were prepared into cross-section specimens. The sections were examined by 3D and laser measuring morphology. Zones were identified in the lesions on the basis of their optical appearance. Two zones were identified in the lesions on the basis of their laser appearance. The microstructure showed that the tubular was partly closed in transparent dentin; peritubular and intertubular dentin were reduced in the zone of demineralization; peritubular and intertubular dentin were damaged and fused; a beaded sample and oval lesions formed in the zone of bacterial invasion; and abnormal dentin structure was present in the zone of destruction on the basis of their laser appearance. Four zones were iden-tified in the lesions according to their colors, as determined from their 3D appearance. 3D laser scanning micros-cope may be a powerful, accessible, and non-destructive technique, as it identified the lesion and tubular zones, as well as peritubular and intertubular dentin in the four zones' lesions. The microstructure of dentin caries lesions may have significant merit in the evaluation of clinical prevention and treatment.

  18. Nano-pulsed laser irradiation scanning system for phase-change materials

    International Nuclear Information System (INIS)

    Kim, Sookyung; Li Xuezhe; Lee, Sangbin; Kim, Kyung-Ho; Lee, Seung-Yop

    2008-01-01

    Recently, the demand of a laser irradiation tester is increasing for phase change random access memory (PRAM) as well as conventional optical storage media. In this study, a nano-pulsed laser irradiation system is developed to characterize the optical property and writing performance of phase-change materials, based on a commercially available digital versatile disk (DVD) optical pick-up. The precisely controlled focusing and scanning on the material's surface are implemented using the auto-focusing mechanism and a voice coil motor (VCM) of the commercial DVD pick-up. The laser irradiation system provides various writing and reading functions such as adjustable laser power, pulse duration, recording pattern (spot, line and area), and writing/reading repetition, phase transition, and in situ reflectivity measurement before/after irradiation. Measurements of power time effect (PTE) diagram and reflectivity map of Ge 2 Sb 2 Te 5 samples show that the proposed laser irradiation system provides the powerful scanning tool to quantify the optical characteristics of phase-change materials

  19. In vitro evaluation of laser fluorescence devices for caries detection through stereomicroscopic imaging.

    Science.gov (United States)

    Oancea, Roxana; Podariu, Angela Codruţa; Vasile, Liliana; Sava-Roşianu, Ruxandra; Folescu, Roxana

    2013-01-01

    The aims of this study were to determine the diagnostic accuracy and reproducibility of the laser fluorescence device (LF), and the relationship between laser fluorescence readings taken at the entrance of the fissure, ICDAS visual examination caries detection system and the histological depth of the lesion. Two hundred and forty teeth (122 human third molars and 118 bicuspids) were selected from 62 patients enrolled in the study. Visual and LF examinations (Diagnodent, Kavo, Biberach, Germany) of the occlusal surfaces were performed in vivo. After tooth extraction, histological sections were evaluated by stereomicroscopy in vitro. Statistical analysis was performed using multiple statistical methods (SPSS ver. 17). Intra-examiner reproducibility for the LF measurements was excellent: intra-class-correlation coefficient (ICC) for LF was 0.957. Kappa values for each examiner's reproducibility were 0.74-0.82. The diagnostic performance of the LF device gave a good overall diagnostic accuracy according to ICDAS II codes and histological values as indicated by the area under the ROC curve of 0.707 and 0.709 respectively. The results of the study showed acceptable diagnostic accuracy for the laser fluorescence device. This supports the view that dentists can be site specific in applying fluorescence-based devices to multiple discrete sites within the same surface. In conclusion, these diagnostic methods have different characteristics, indications and limitations for use. In order to detect caries on occlusal surfaces thoroughly, a combination of methods would be the best practice moderated by clinical knowledge and experience.

  20. Reaction-time-resolved measurements of laser-induced fluorescence in a shock tube with a single laser pulse

    Science.gov (United States)

    Zabeti, S.; Fikri, M.; Schulz, C.

    2017-11-01

    Shock tubes allow for the study of ultra-fast gas-phase reactions on the microsecond time scale. Because the repetition rate of the experiments is low, it is crucial to gain as much information as possible from each individual measurement. While reaction-time-resolved species concentration and temperature measurements with fast absorption methods are established, conventional laser-induced fluorescence (LIF) measurements with pulsed lasers provide data only at a single reaction time. Therefore, fluorescence methods have rarely been used in shock-tube diagnostics. In this paper, a novel experimental concept is presented that allows reaction-time-resolved LIF measurements with one single laser pulse using a test section that is equipped with several optical ports. After the passage of the shock wave, the reactive mixture is excited along the center of the tube with a 266-nm laser beam directed through a window in the end wall of the shock tube. The emitted LIF signal is collected through elongated sidewall windows and focused onto the entrance slit of an imaging spectrometer coupled to an intensified CCD camera. The one-dimensional spatial resolution of the measurement translates into a reaction-time-resolved measurement while the species information can be gained from the spectral axis of the detected two-dimensional image. Anisole pyrolysis was selected as the benchmark reaction to demonstrate the new apparatus.

  1. Three-dimensional hard and soft tissue imaging of the human cochlea by scanning laser optical tomography (SLOT.

    Directory of Open Access Journals (Sweden)

    Nadine Tinne

    Full Text Available The present study focuses on the application of scanning laser optical tomography (SLOT for visualization of anatomical structures inside the human cochlea ex vivo. SLOT is a laser-based highly efficient microscopy technique which allows for tomographic imaging of the internal structure of transparent specimens. Thus, in the field of otology this technique is best convenient for an ex vivo study of the inner ear anatomy. For this purpose, the preparation before imaging comprises decalcification, dehydration as well as optical clearing of the cochlea samples in toto. Here, we demonstrate results of SLOT imaging visualizing hard and soft tissue structures with an optical resolution of down to 15 μm using extinction and autofluorescence as contrast mechanisms. Furthermore, the internal structure can be analyzed nondestructively and quantitatively in detail by sectioning of the three-dimensional datasets. The method of X-ray Micro Computed Tomography (μCT has been previously applied to explanted cochlea and is solely based on absorption contrast. An advantage of SLOT is that it uses visible light for image formation and thus provides a variety of contrast mechanisms known from other light microscopy techniques, such as fluorescence or scattering. We show that SLOT data is consistent with μCT anatomical data and provides additional information by using fluorescence. We demonstrate that SLOT is applicable for cochlea with metallic cochlear implants (CI that would lead to significant artifacts in μCT imaging. In conclusion, the present study demonstrates the capability of SLOT for resolution visualization of cleared human cochleae ex vivo using multiple contrast mechanisms and lays the foundation for a broad variety of additional studies.

  2. Optical scanner system for high resolution measurement of lubricant distributions on metal strips based on laser induced fluorescence

    Science.gov (United States)

    Holz, Philipp; Lutz, Christian; Brandenburg, Albrecht

    2017-06-01

    We present a new optical setup, which uses scanning mirrors in combination with laser induced fluorescence to monitor the spatial distribution of lubricant on metal sheets. Current trends in metal processing industry require forming procedures with increasing deformations. Thus a welldefined amount of lubricant is necessary to prevent the material from rupture, to reduce the wearing of the manufacturing tool as well as to prevent problems in post-deforming procedures. Therefore spatial resolved analysis of the thickness of lubricant layers is required. Current systems capture the lubricant distribution by moving sensor heads over the object along a linear axis. However the spatial resolution of these systems is insufficient at high strip speeds, e.g. at press plants. The presented technology uses fast rotating scanner mirrors to deflect a laser beam on the surface. This 405 nm laser light excites the autofluorescence of the investigated lubricants. A coaxial optic collects the fluorescence signal which is then spectrally filtered and recorded using a photomultiplier. From the acquired signal a two dimensional image is reconstructed in real time. This paper presents the sensor setup as well as its characterization. For the calibration of the system reference targets were prepared using an ink jet printer. The presented technology for the first time allows a spatial resolution in the millimetre range at production speed. The presented test system analyses an area of 300 x 300 mm² at a spatial resolution of 1.1 mm in less than 20 seconds. Despite this high speed of the measurement the limit of detection of the system described in this paper is better than 0.05 g/m² for the certified lubricant BAM K-009.

  3. A novel laser-induced fluorescence scheme for Ar-I in a plasma.

    Science.gov (United States)

    Short, Zachary D; Siddiqui, M Umair; Henriquez, Miguel F; McKee, John S; Scime, Earl E

    2016-01-01

    Here we describe a novel infrared laser-induced fluorescence scheme for the 1s2 state of Ar-I using an 841.052 nm (vacuum) Sacher tunable diode laser oscillator and compare it to an established 667.913 nm (vacuum) 1s4-pumping Ar-I LIF scheme using a master oscillator power amplifier laser [A. M. Keesee et al. Rev. Sci. Instrum. 75, 4091 (2004)]. The novel scheme exhibits a significantly greater signal-to-noise ratio for a given injected laser power than the established scheme. We argue that this is caused by less intense spontaneous Ar-I radiation near the LIF emission wavelength for the 1s2 scheme as compared to the 1s4 scheme. In addition we present an updated iodine cell spectrum around the 1s4 LIF scheme pump wavelength.

  4. Novel xenon calibration scheme for two-photon absorption laser induced fluorescence of hydrogen

    International Nuclear Information System (INIS)

    Elliott, Drew; Scime, Earl; Short, Zachary

    2016-01-01

    Two photon absorption laser induced fluorescence (TALIF) measurements of neutral hydrogen and its isotopes are typically calibrated by performing TALIF measurements on krypton with the same diagnostic system and using the known ratio of the absorption cross sections [K. Niemi et al., J. Phys. D 34, 2330 (2001)]. Here we present the measurements of a new calibration method based on a ground state xenon scheme for which the fluorescent emission wavelength is nearly identical to that of hydrogen, thereby eliminating chromatic effects in the collection optics and simplifying detector calibration. We determine that the ratio of the TALIF cross sections of xenon and hydrogen is 0.024 ± 0.001.

  5. Laser-induced absorption and fluorescence studies of photochromic Schiff bases

    DEFF Research Database (Denmark)

    Kownacki, K.; Mordzinski, A.; Wilbrandt, R.

    1994-01-01

    Three photochromic Schiff bases: N-salicylideneaniline (SA), N-salicylidene-1-naphthylamine (SN), and N,N-bis-(salicylidene)-p-phenylenediamine (Bsp), were studied in acetonitrile by means of steady-state and time-resolved absorption and fluorescence spectroscopy, as well as semiempirical quantum...... chemical calculations. In all these molecules, the transient absorption and two-step laser-induced fluorescence spectra of long-lived transients are remarkably similar. The photochromic species is tentatively assigned to the non-hydrogen bonded form of the proton transfer reaction product...

  6. The Investigation of Accuracy of 3 Dimensional Models Generated From Point Clouds with Terrestrial Laser Scanning

    Science.gov (United States)

    Gumus, Kutalmis; Erkaya, Halil

    2013-04-01

    In Terrestrial laser scanning (TLS) applications, it is necessary to take into consideration the conditions that affect the scanning process, especially the general characteristics of the laser scanner, geometric properties of the scanned object (shape, size, etc.), and its spatial location in the environment. Three dimensional models obtained with TLS, allow determining the geometric features and relevant magnitudes of the scanned object in an indirect way. In order to compare the spatial location and geometric accuracy of the 3-dimensional model created by Terrestrial laser scanning, it is necessary to use measurement tools that give more precise results than TLS. Geometric comparisons are performed by analyzing the differences between the distances, the angles between surfaces and the measured values taken from cross-sections between the data from the 3-dimensional model created with TLS and the values measured by other measurement devices The performance of the scanners, the size and shape of the scanned objects are tested using reference objects the sizes of which are determined with high precision. In this study, the important points to consider when choosing reference objects were highlighted. The steps up to processing the point clouds collected by scanning, regularizing these points and modeling in 3 dimensions was presented visually. In order to test the geometric correctness of the models obtained by Terrestrial laser scanners, sample objects with simple geometric shapes such as cubes, rectangular prisms and cylinders that are made of concrete were used as reference models. Three dimensional models were generated by scanning these reference models with Trimble Mensi GS 100. The dimension of the 3D model that is created from point clouds was compared with the precisely measured dimensions of the reference objects. For this purpose, horizontal and vertical cross-sections were taken from the reference objects and generated 3D models and the proximity of

  7. Quasi-resonance enhancement of laser-induced-fluorescence diagnosis of endometriosis

    Science.gov (United States)

    Hill, Ralph H., Jr.; Vancaillie, Thierry G.

    1990-05-01

    Endometriosis, a common disease in women in the reproductive age group, is defined pathologically by the presence of endometrial tissue (inner lining of the uterus) outside the uterus. The displaced tissue is histologically identical to endometrium. In addition to being a highly prevalent disease, this disease is associated with many distressing and debilitating symptoms. Motivated by the need to improve diagnosis by endoscopic imaging instrumentation, we have previously used several drugs to cause selective laser-induced fluorescence of active surgically induced endometriosis in the rabbit model in vivo using ultraviolet-wavelength (351.1 and 363.8 nm) excitation from an argon-ion laser. In the present study we have investigated methods of enhancing differentiation between normal and abnormal tissue by using other excitation wavelengths. In addition to an enhanced capability for detecting abnormal tissue, there are several other advantages associated with using visible-wavelength excitation, such as deeper penetration into the tissue, as well as increased equipment performance, reliability, versatility, and availability. The disadvantage is that because only wavelengths longer than the excitation wavelength can be used for detection, some of the spectral information is lost. Because human endomeiriosis samples were somewhat limited in quantity, as well as specimen size, we used normal ovarian tissue for the laser-induced-fluorescence differentiation-enhancement studies. Positive enhancement of the laser-induced- fluorescence differentiation was found in human ovarian tissue in vitro utilizing 514.5-nm excitation from an argonion laser. Additionally, preliminary verification of this concept was accomplished in active surgically induced endometriosis in the rabbit model in vivo with visible argon-ion laser excitation of two tetracycline-based drugs. Future experiments with other drug treatments and excitation/detection parameters are planned.

  8. A novel cryogenic scanning laser microscope tested on Josephson tunnel junctions

    DEFF Research Database (Denmark)

    Holm, Jesper; Mygind, Jesper

    1995-01-01

    A novel cryogenic scanning laser microscope with a spatial resolution of less than 5 µm has been designed for on-chip in situ investigations of the working properties of normal and superconducting circuits and devices. The instrument relies on the detection of the electrical response of the circuit...... to a very localized heating induced by irradiation with 675 nm wavelength light from a semiconductor laser. The hot spot is moved by a specially designed piezoelectric scanner sweeping the tip of a single-mode optical fiber a few µm above the circuit. Depending on the scanner design the scanning area can...... be as large as 50×500 µm2 at 4.2 K. The microscope can be operated in the temperature range 2–300 K using a standard temperature controller. The central microscope body is mounted inside the vacuum can of a dip-stick-type cryoprobe. A damped spring system is used to reduce interference from extraneous...

  9. Damage Detection on Thin-walled Structures Utilizing Laser Scanning and Standing Waves

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Se Hyeok; Jeon, Jun Young; Kim, Du Hwan; Park, Gyuhae [Chonnam Nat’l Univ., Gwangju (Korea, Republic of); Kang, To; Han, Soon Woo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-05-15

    This paper describes wavenumber filtering for damage detection using single-frequency standing wave excitation and laser scanning sensing. An embedded piezoelectric sensor generates ultrasonic standing waves, and the responses are measured using a laser Doppler vibrometer and mirror tilting device. After scanning, newly developed damage detection techniques based on wavenumber filtering are applied to the full standing wave field. To demonstrate the performance of the proposed techniques, several experiments were performed on composite plates with delamination and aluminum plates with corrosion damage. The results demonstrated that the developed techniques could be applied to various structures to localize the damage, with the potential to improve the damage detection capability at a high interrogation speed.

  10. Microstructures and Microhardness Properties of CMSX-4® Additively Fabricated Through Scanning Laser Epitaxy (SLE)

    Science.gov (United States)

    Basak, Amrita; Holenarasipura Raghu, Shashank; Das, Suman

    2017-12-01

    Epitaxial CMSX-4® deposition is achieved on CMSX-4® substrates through the scanning laser epitaxy (SLE) process. A thorough analysis is performed using various advanced material characterization techniques, namely high-resolution optical microscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy, x-ray diffraction, and Vickers microhardness measurements, to characterize and compare the quality of the SLE-fabricated CMSX-4® deposits to the CMSX-4® substrates. The results show that the CMSX-4® deposits have smaller primary dendritic arm spacing, finer γ/ γ' size, weaker elemental segregation, and higher microhardness compared to the investment cast CMSX-4® substrates. The results presented here demonstrate that CMSX-4® is an attractive material for laser-based AM processing and, therefore, can be used in the fabrication of gas turbine hot-section components through AM processing.

  11. As- built inventory of the office building with the use of terrestrial laser scanning

    Directory of Open Access Journals (Sweden)

    Przyborski Marek

    2018-01-01

    Full Text Available Terrestrial Laser Scanning (TLS is an efficient tool for building inventories. Based on the red- laser beam technology it is possible to provide the high accuracy data with complete spatial information about a scanned object. In this article, authors present the solution of use a TLS in as-built inventory of the office building. Based on the provided data, it is possible to evaluate the correctness of built details of a building and provide information for further construction works, for example an area needed for Styrofoam installation. The biggest problem in this research is that an error which equals over 1cm could generate costs, which could be a problem to cover by a constructor. Based on a complicated place of the construction works (centre of a city it was a challenge to maintain the accuracy.

  12. As- built inventory of the office building with the use of terrestrial laser scanning

    Science.gov (United States)

    Przyborski, Marek; Tysiąc, Paweł

    2018-01-01

    Terrestrial Laser Scanning (TLS) is an efficient tool for building inventories. Based on the red- laser beam technology it is possible to provide the high accuracy data with complete spatial information about a scanned object. In this article, authors present the solution of use a TLS in as-built inventory of the office building. Based on the provided data, it is possible to evaluate the correctness of built details of a building and provide information for further construction works, for example an area needed for Styrofoam installation. The biggest problem in this research is that an error which equals over 1cm could generate costs, which could be a problem to cover by a constructor. Based on a complicated place of the construction works (centre of a city) it was a challenge to maintain the accuracy.

  13. Noninvasive multiphoton imaging of cardiovascular structures using NIR femtosecond laser scanning microscopy

    Science.gov (United States)

    Schenke-Layland, Katja; Riemann, Iris; Stock, Ulrich A.; Konig, Karsten

    2004-07-01

    Near infrared (NIR) femtosecond laser scanning microscopy represents a novel and very promising medical diagnostic imaging technology for non-invasive cross-sectional analysis of living biological tissues. In this study multiphoton imaging has been performed to analyze the structural features of extracellular matrix (ECM) components, e.g. collagen and elastin, of living pulmonary and aortic heart valves. High-resolution autofluorescence and second harmonic generation (SHG) images of collagenous and elastic fibers were demonstrated using multifluorophore, multiphoton excitation at two different wavelengths and non-invasive optical sectioning, without the need of embedding or staining. The quality of the resulting three-dimensional images allowed exact differentiation of the ECM components. These experimental results indicated that NIR femtosecond laser scanning microscopy may prove to be a useful tool for the non-destructive monitoring and characterization of cardiovascular structures.

  14. Three-Dimensional Digital Documentation of Heritage Sites Using Terrestrial Laser Scanning and Unmanned Aerial Vehicle Photogrammetry

    Science.gov (United States)

    Jo, Y. H.; Kim, J. Y.

    2017-08-01

    Three-dimensional digital documentation is an important technique for the maintenance and monitoring of cultural heritage sites. This study focuses on the three-dimensional digital documentation of the Magoksa Temple, Republic of Korea, using a combination of terrestrial laser scanning and unmanned aerial vehicle (UAV) photogrammetry. Terrestrial laser scanning mostly acquired the vertical geometry of the buildings. In addition, the digital orthoimage produced by UAV photogrammetry had higher horizontal data acquisition rate than that produced by terrestrial laser scanning. Thus, the scanning and UAV photogrammetry were merged by matching 20 corresponding points and an absolute coordinate system was established using seven ground control points. The final, complete threedimensional shape had perfect horizontal and vertical geometries. This study demonstrates the potential of integrating terrestrial laser scanning and UAV photogrammetry for three-dimensional digital documentation. This new technique is expected to contribute to the three-dimensional digital documentation and spatial analysis of cultural heritage sites.

  15. Selective removal of dental composite using a rapidly scanned carbon dioxide laser

    Science.gov (United States)

    Chan, Kenneth H.; Fried, Daniel

    2011-03-01

    Dental restorative materials are color matched to the tooth and are difficult to remove by mechanical means without excessive removal or damage to peripheral enamel and dentin. Lasers are ideally suited for selective ablation to minimize healthy tissue loss when replacing existing restorations, sealants or removing composite adhesives such as residual composite left after debonding orthodontic brackets. In this study a carbon dioxide laser operating at high laser pulse repetition rates integrated with a galvanometer based scanner was used to selectively remove composite from tooth surfaces. A diode array spectrometer was used to measure the plume emission after each laser pulse and determine if the ablated material was tooth mineral or composite. The composite was placed on tooth buccal and occlusal surfaces and the carbon dioxide laser was scanned across the surface to selectively remove the composite without excessive damage to the underlying sound enamel. The residual composite and the damage to the underlying enamel was evaluated using optical microscopy. The laser was able to rapidly remove the composites rapidly from both surfaces with minimal damage to the underlying sound enamel.

  16. Use of laser fluorescence in dental caries diagnosis: a fluorescence x biomolecular vibrational spectroscopic comparative study.

    Science.gov (United States)

    Carvalho, Fabíola Bastos de; Barbosa, Artur Felipe Santos; Zanin, Fátima Antonia Aparecida; Brugnera Júnior, Aldo; Silveira Júnior, Landulfo; Pinheiro, Antonio Luiz Barbosa

    2013-01-01

    The aim of this work was to verify the existence of correlation between Raman spectroscopy readings of phosphate apatite (~960 cm-1), fluoridated apatite (~575 cm-1) and organic matrix (~1450 cm-1) levels and Diagnodent® readings at different stages of dental caries in extracted human teeth. The mean peak value of fluorescence in the carious area was recorded and teeth were divided in enamel caries, dentin caries and sound dental structure. After fluorescence readings, Raman spectroscopy was carried out on the same sites. The results showed significant difference (ANOVA, pfluorescence readings for enamel (16.4 ± 2.3) and dentin (57.6 ± 23.7) on carious teeth. Raman peaks of enamel and dentin revealed that ~575 and ~960 cm-1 peaks were more intense in enamel caries. There was significant negative correlation (pfluorescence detected by Diagnodent the lower the peaks of phosphate apatite and fluoridated apatite. As the early diagnosis of caries is directly related to the identification of changes in the inorganic tooth components, Raman spectroscopy was more sensitive to variations of these components than Diagnodent.

  17. Laser excited nonresonant fluorescence spectroscopy. Second annual progress report

    International Nuclear Information System (INIS)

    Gelbwachs, J.A.; Frueholz, R.P.

    1980-01-01

    The relative populations of numerous tin levels populated by collisional energy transfer from an initially laser pumped level were obtained. These populations yield information concerning the relative rates of energy transfer for the various buffer gases studied. The results indicated two distinct energy transfer behaviors. First, for certain tin levels diatomic collision partners produce populations nearly two orders of magnitude higher than when rare gases are present. This behavior is attributed to the effects of near-resonant energy transfer pathways for the E → V/R and V/R → E processes found in the diatomic collision partners. Second, for other tin levels, diatomics and rare gases transfer population approximately at the same rates and more efficiently than in the former case. For these levels the near-resonant pathways can be obscured by means of a more effective energy transfer channel common to both diatomics and rare gases such as by curve crossing mechanisms

  18. Temperature measurements in hypersonic air flows using laser-induced O2 fluorescence

    Science.gov (United States)

    Laufer, Gabriel; Mckenzie, Robert L.

    1988-01-01

    An investigation is reported of the use of laser-induced fluorescence on oxygen for the measurement of air temperature and its fluctuations owing to turbulence in hypersonic wind tunnel flows. The results show that for temperatures higher than 60 K and densities higher than 0.01 amagat, the uncertainty in the temperature measurement can be less than 2 percent if it is limited by photon-statistical noise. The measurement is unaffected by collisional quenching and, if the laser fluence is kept below 1.5 J/sq cm, it is also unaffected by nonlinear effects which are associated with depletion of the absorbing states.

  19. Feasibility of measuring temperature and density fluctuations in air using laser-induced O2 fluorescence

    Science.gov (United States)

    Massey, G. A.; Lemon, C. J.

    1984-01-01

    A tunable line-narrowed ArF laser can selectively excite several rotation al lines of the Schumann-Runge band system of O2 in air. The resulting ultraviolet fluorescence can be monitored at 90 deg to the laser beam axis, permitting space and time resolved observation of density and temperature fluctuations in turbulence. Experiments and calculations show that + or - 1 K, + or - 1 percent density, 1 cu mm spatial, and 1 microsecond temporal resolution can be achieved simultaneously under some conditions.

  20. Assessing Metrics for Estimating Fire Induced Change in the Forest Understorey Structure Using Terrestrial Laser Scanning

    OpenAIRE

    Gupta, Vaibhav; Reinke, Karin; Jones, Simon; Wallace, Luke; Holden, Lucas

    2015-01-01

    Quantifying post-fire effects in a forested landscape is important to ascertain burn severity, ecosystem recovery and post-fire hazard assessments and mitigation planning. Reporting of such post-fire effects assumes significance in fire-prone countries such as USA, Australia, Spain, Greece and Portugal where prescribed burns are routinely carried out. This paper describes the use of Terrestrial Laser Scanning (TLS) to estimate and map change in the forest understorey following a prescribed bu...

  1. Functional characterization of planar sensors with active edges using laser and X-ray beam scans

    International Nuclear Information System (INIS)

    Povoli, M.; Bagolini, A.; Boscardin, M.; Dalla Betta, G.-F.; Giacomini, G.; Hasi, J.; Oh, A.; Zorzi, N.

    2013-01-01

    We report on the functional characterization of planar sensors with active edges fabricated at Fondazione Bruno Kessler (FBK), Trento, Italy. The measurements here reported were performed by means of laser and X-ray beam scans mainly focusing on the signal efficiency of the edge region of the devices. Results are very encouraging and show very good sensitivity up to few microns away from the device physical edge

  2. Functional characterization of planar sensors with active edges using laser and X-ray beam scans

    Energy Technology Data Exchange (ETDEWEB)

    Povoli, M., E-mail: povoli@disi.unitn.it [Dipartimento di Ingegneria e Scienza dell' Informazione, Università di Trento, Via Sommarive, 14, I-38123 Povo di Trento (Italy); INFN, Sezione di Padova (Gruppo Collegato di Trento),Via Sommarive, 14, I-38123 Povo di Trento (Italy); Bagolini, A.; Boscardin, M. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive, 18, I-38123 Povo di Trento (Italy); Dalla Betta, G.-F. [Dipartimento di Ingegneria e Scienza dell' Informazione, Università di Trento, Via Sommarive, 14, I-38123 Povo di Trento (Italy); INFN, Sezione di Padova (Gruppo Collegato di Trento),Via Sommarive, 14, I-38123 Povo di Trento (Italy); Giacomini, G. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive, 18, I-38123 Povo di Trento (Italy); Hasi, J. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025-7015 (United States); Oh, A. [The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Zorzi, N. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive, 18, I-38123 Povo di Trento (Italy)

    2013-08-01

    We report on the functional characterization of planar sensors with active edges fabricated at Fondazione Bruno Kessler (FBK), Trento, Italy. The measurements here reported were performed by means of laser and X-ray beam scans mainly focusing on the signal efficiency of the edge region of the devices. Results are very encouraging and show very good sensitivity up to few microns away from the device physical edge.

  3. Automatic Construction of Hypotheses for Linear Objects in Digital and Laser Scanning Images

    Directory of Open Access Journals (Sweden)

    Quintino Dalmolin

    2004-12-01

    Full Text Available This paper presents an automatic road hypotheses approach using digital image and laser scanning image combining various Digital Image Processing techniques. The semantic objects, in this work, are linear features, such as, roads and streets. The aim of this paper is extract automatically road hypotheses on image space and object space for use the information in automatic absolute orientation process. The results show that methodology is efficiency and the roads hypotheses are generate and validate.

  4. Using terrestrial laser scanning data to drive decimetric resolution urban inundation models

    Science.gov (United States)

    Fewtrell, Timothy; Duncan, Alastair; Horritt, Matthew; Bates, Paul

    2010-05-01

    The availability of LiDAR data has led to the proliferation a wide variety of research streams from DEM segmentation (Mason et al., 2007) to mapping the vertical profile of vegetation (Blair et al., 1999) and floodplain inundation modelling (Bates et al., 2003). As the specifications of LiDAR systems have improved, the vertical accuracy and spatial resolution of airborne systems have increased to ~5-10 cm and ~25 cm respectively (Baltsavias, 1999), giving highly resolved digital surface models (DSMs) of the urban environment (Mason et al., 2007). More recently, terrestrial laser scanners have started to be employed to capture even higher accuracy (i.e. ~1-3cm horizontal resolution) 3D point cloud data for applications in engineering, transportation, urban planning, among others (Lichti et al., 2008). Such very high resolution terrestrial laser scanning data have, however, yet to be used in urban hydraulic models, despite the fact that anecdotal and modelling evidence of the hydraulic process at work during urban floods suggests that features with very small horizontal and vertical length scales (i.e. walls, kerbs, steps, road cambers and storm drains) can have a significant impact on the flow development. In this paper we therefore investigate the potential utility of terrestrial laser scanning data for improving flood risk assessments in urban areas. To do this two key problems have to be dealt with. First, we require methods to process terrestrial laser scanning data in order to extract hydraulically relevant information. As such a number of processing steps are presented and a variety of resolution DEMs are derived. Second, we need to employ highly computationally efficient hydraulic algorithms in order to build models at the scale of the terrestrial laser scanner data and still simulate flows over spatial domains that are not trivially small. In this study, two state-of-the-art numerical models are used to demonstrate complex urban flood flows for pluvial and

  5. Close-range laser scanning in forests: towards physically based semantics across scales.

    Science.gov (United States)

    Morsdorf, F; Kükenbrink, D; Schneider, F D; Abegg, M; Schaepman, M E

    2018-04-06

    Laser scanning with its unique measurement concept holds the potential to revolutionize the way we assess and quantify three-dimensional vegetation structure. Modern laser systems used at close range, be it on terrestrial, mobile or unmanned aerial platforms, provide dense and accurate three-dimensional data whose information just waits to be harvested. However, the transformation of such data to information is not as straightforward as for airborne and space-borne approaches, where typically empirical models are built using ground truth of target variables. Simpler variables, such as diameter at breast height, can be readily derived and validated. More complex variables, e.g. leaf area index, need a thorough understanding and consideration of the physical particularities of the measurement process and semantic labelling of the point cloud. Quantified structural models provide a framework for such labelling by deriving stem and branch architecture, a basis for many of the more complex structural variables. The physical information of the laser scanning process is still underused and we show how it could play a vital role in conjunction with three-dimensional radiative transfer models to shape the information retrieval methods of the future. Using such a combined forward and physically based approach will make methods robust and transferable. In addition, it avoids replacing observer bias from field inventories with instrument bias from different laser instruments. Still, an intensive dialogue with the users of the derived information is mandatory to potentially re-design structural concepts and variables so that they profit most of the rich data that close-range laser scanning provides.

  6. Use of multi-photon laser-scanning microscopy to describe the distribution of xenobiotic chemicals in fish early life stages

    Energy Technology Data Exchange (ETDEWEB)

    Hornung, Michael W.; Cook, Philip M.; Flynn, Kevin M.; Lothenbach, Doug B.; Johnson, Rodney D.; Nichols, John W

    2004-03-30

    To better understand the mechanisms by which persistent bioaccumulative toxicants (PBTs) produce toxicity during fish early life stages (ELS), dose-response relationships need to be understood in relation to the dynamic distribution of chemicals in sensitive tissues. In this study, a multi-photon laser scanning microscope (MPLSM) was used to determine the multi-photon excitation spectra of several polyaromatic hydrocarbons (PAHs) and to describe chemical distribution among tissues during fish ELS. The multi-photon excitation spectra revealed intense fluorescent signal from the model fluorophore, pentamethyl-difluoro-boro-indacene (BODIPY[reg], less signal from benzo[a]pyrene and fluoranthene, and no detectable signal from pyrene. The imaging method was tested by exposing newly fertilized medaka (Oryzias latipes) eggs to BODIPY[reg] or fluoranthene for 6 h, followed by transfer to clean media. Embryos and larvae were then imaged through 5 days post-hatch. The two test chemicals partitioned similarly throughout development and differences in fluorescence intensity among tissues were evident to a depth of several hundred microns. Initially, the most intense signal was observed in the oil droplet within the yolk, while a moderate signal was seen in the portion of the yolk containing the yolk-platelets. As embryonic development progressed, the liver biliary system, gall bladder, and intestinal tract accumulated strong fluorescent signal. After hatch, once the gastrointestinal tract was completely developed, most of the fluorescent signal was cleared. The MPLSM is a useful tool to describe the tissue distribution of fluorescent PBTs during fish ELS.

  7. Detection of adherence of Enterococcus faecalis in infected dentin of extracted human teeth using confocal laser scanning microscope: An In vitro Study

    Directory of Open Access Journals (Sweden)

    V Siddharth Nair

    2017-01-01

    Full Text Available Aim: The aim of this study is to detect in vitro adherence of Enterococcus faecalis to the infected dentinal tubules of human extracted teeth using confocal laser scanning microscope. Subjects and Methods: Roots from human premolar teeth (n = 40 were infected with E. faecalis strain the American Type Culture Collection 29212 in brain heart infusion for 21 days. After the experimental period, specimens were divided into two groups, Group A (n = 20, Group B (n = 20, and Group A specimens were stained with fluorescein diacetate dye for the detection of viability and adherence Group B were stained with acridine orange dye for detection of metabolic activity and adherence. Samples were washed, thoroughly sectioned and examined by confocal laser scanning microscopy. Computer-assisted determinants of fluorescence, bacterial viability, metabolic activity, and adherence were compared statistically. Results: E. faecalis was able to invade the dentinal tubules to a depth of 1–400 μm and adhere to 1–200 μm depth. Adherence (90% was significantly higher in 1–100 μm using fluorescein diacetate and acridine orange dye. Conclusion: Adherence of E. faecalis as evaluated by confocal laser scanning microscope was highest at the depth of 1–100 μm which may have an impact on the shaping and cleaning procedures on the root canal.

  8. Experimentally studied laser fluorescence method for remote sensing of plant stress situation induced by improper plants watering

    Directory of Open Access Journals (Sweden)

    Yu. V. Fedotov

    2014-01-01

    Full Text Available Stressful situations of plants can be caused by a lack of nutrients; mechanical damages; diseases; low or high temperatures; lack of illumination; insufficient or excess humidity of the soil; soil salinization; soil pollution by oil products or heavy metals; the increased acidity of the soil; use of pesticides, herbicides, insecticides, etc.At early stages it is often difficult to detect seemingly that the plants are in stressful situations caused by adverse external factors. However, the fluorescent analysis potentially allows detection of the stressful situations of plants by deformation of laser-induced fluorescence spectra. The paper conducts experimental investigations to learn the capabilities of the laser fluorescent method to monitor plant situations at 532nm wavelength of fluorescence excitation in the stressful situations induced by improper watering (at excess of moisture in the soil and at a lack of moisture.Researches of fluorescence spectra have been conducted using a created laboratory installation. As a source to excite fluorescence radiation the second harmonica of YAG:Nd laser is used. The subsystem to record fluorescence radiation is designed using a polychromator and a highly sensitive matrix detector with the amplifier of brightness.Experimental investigations have been conducted for fast-growing and unpretentious species of plants, namely different sorts of salad.Experimental studies of laser-induced fluorescence spectra of plants for 532nm excitement wavelength show that the impact of stressful factors on a plant due to the improper watering, significantly distorts a fluorescence spectrum of plants. Influence of a stressful factor can be shown as a changing profile of a fluorescence spectrum (an identifying factor, here, is a relationship of fluorescence intensities at two wavelengths, namely 685 nm and 740 nm or (and as a changing level of fluorescence that can be the basis for the laser method for monitoring the plant

  9. Geometric validation of a mobile laser scanning system for urban applications

    Science.gov (United States)

    Guan, Haiyan; Li, Jonathan; Yu, Yongtao; Liu, Yan

    2016-03-01

    Mobile laser scanning (MLS) technologies have been actively studied and implemented over the past decade, as their application fields are rapidly expanding and extending beyond conventional topographic mapping. Trimble's MX-8, as one of the MLS systems in the current market, generates rich survey-grade laser and image data for urban surveying. The objective of this study is to evaluate whether Trimble MX-8 MLS data satisfies the accuracy requirements of urban surveying. According to the formula of geo-referencing, accuracies of navigation solution and laser scanner determines the accuracy of the collected LiDAR point clouds. Two test sites were selected to test the performance of Trimble MX-8. Those extensive tests confirm that Trimble MX-8 offers a very promising tool to survey complex urban areas.

  10. Atomic force microscopy and confocal laser scanning microscopy on the cytoskeleton of permeabilised and embedded cells

    International Nuclear Information System (INIS)

    Meller, Karl; Theiss, Carsten

    2006-01-01

    We describe a technical method of cell permeabilisation and embedding to study the organisation and distribution of intracellular proteins with aid of atomic force microscopy and confocal laser scanning microscopy in identical areas. While confocal laser scanning microscopy is useful for the identification of certain proteins subsequent labelling with markers or antibodies, atomic force microscopy allows the observation of macromolecular structures in fixed and living cells. To demonstrate the field of application of this preparatory technique, cells were permeabilised, fixed, and the actin cytoskeleton was stained with phalloidin-rhodamine. Confocal laser scanning microscopy was used to show the organisation of these microfilaments, e.g. geodesic dome structures. Thereafter, cells were embedded in Durcupan water-soluble resin, followed by UV-polymerisation of resin at 4 o C. This procedure allowed intracellular visualisation of the cell nucleus or cytoskeletal elements by atomic force microscopy, for instance to analyse the globular organisation of actin filaments. Therefore, this method offers a great potential to combine both microscopy techniques in order to understand and interpret intracellular protein relations, for example, the biochemical and morphological interaction of the cytoskeleton

  11. Visual and laser Doppler perfusion scanning assessments of Kathon CG patch test reactions.

    Science.gov (United States)

    Bjarnason, B; Fischer, T

    1998-12-01

    Testing procedure for Kathon CG (Diagnostics AB, Tygelsjö, Sweden) is not standardized. To improve test results for Kathon CG. Eleven subjects were tested with Kathon CG patch tests applied from 6 to 96 hours. Tests were read visually and by a laser Doppler perfusion scanning technique at time points ranging from 6 to 240 hours. There were large differences in the perfusion profiles of subjects tested in identical fashion. Beginning reactions were detected earlier with the laser Doppler scanning than with the visual assessment technique. There was no obvious agreement between peak perfusion values of reactions and application times. Both assessment techniques were effective at distinguishing between positive and negative subjects at an adequate dose and application time. This distinction was possible using a shorter reading time with the laser Doppler scanning for all subjects. Six-hour applications were sufficient to detect all positive subjects so tested regardless of assessment technique. With that application time, positive and negative subjects were most effectively identified using long reading times regardless of assessment technique. The shortest application time used on all subjects, 24 hours, was effective and 6-hour applications with long reading times for all subjects so tested. Doses lower than 0.0040 mg/cm2 resulted in false-negative tests.

  12. Auto-synchronized laser scanning range sensor for thermoplastic pavement marking material thickness measurement

    Science.gov (United States)

    Sun, Wei; Chen, Xuemin; Chen, Yuanhang; Ekbote, Aditya; Liu, Richard Ce

    2006-03-01

    Pavement marking materials provide delineation on highways around the world. The condition of the marking materials is very important for the driver's safety as well as the comfort and the driving expenses. Currently thermoplastic pavement marking materials (TPMM) are widely used in states. Measuring the thickness of TPMM on pavement is an essential index to monitor the contractors, calculate durability of marking materials, and provide better information for the pavement marking evaluation. In recent years to measure the thickness of TPMM, a procedure involving pre-embedded plates sprayed with the marking materials has been widely accepted. This method is labor intensive, and cannot obtain a continuous-thickness profile. Therefore there are demands to develop a high-speed automatic measuring system for determining the thickness and uniformity of marking materials. In this paper, a laser range sensor based on auto-synchronized laser scanning is proposed for the thermoplastic pavement marking material thickness measurement. Compare to classical triangulation method, this approach doesn't scarify the system resolution for large field of view and it is more suitable for highway speed measurement. To achieve high speed measurement, PSD (Position Sensitive Detector) is used in the prototype system instead of CCD (Charge Couple Device) in traditional auto-synchronized system. The standoff distance and transverse scan range of the prototype system both are 1 foot. The lab test results show that the prototype system can measure the thermoplastic type thickness with error in 5mil at laser scanning rate up to 50Hz.

  13. Directional radiative transfer by SCOPE, SLC and DART using laser scan derived structural forest parameters

    Science.gov (United States)

    Timmermans, Joris; Gastellu-Etchegorry, Jean Philippe; van der Tol, Christiaan; Verhoef, Wout; Vekerdy, Zoltan; Su, Zhongbo

    2017-04-01

    terrestrial laser scan of the Speulderbos in the Netherlands. The comparison between DART and SCOPE/SLC models showed a good match for the simple scenarios. Calculated rMSDs showed lower than 7.5% errors for crown coverage values lower than 0.87, with the Near-Hotspot viewing angles found to be the largest contributor to this deviation. For more complex scenarios (using Multiple Crowns), the comparison between SCOPE and DART showed mixed results. Good results were obtained for crown coverage values of 0.93, with rMSD (6.77% and 5.96%), lower than the defined threshold value, except near hotspot. For scenarios with crown coverages lower than 0.93 the rMSD were too large to validate the use of SCOPE model. When considering the Soil Leaf Canopy (SLC) model, an improved version of SAIL that considers the canopy clumping, better results were obtained for these complex scenarios, with good agreement for medium crown coverage values (0.93 and 0.87) with rMSD (6.33% and 5.99; 6.66% and 7.12%). This indicates that the radiative transfer model within SCOPE might be upgraded in the future.

  14. A total internal reflection-fluorescence correlation spectroscopy setup with pulsed diode laser excitation.

    Science.gov (United States)

    Weger, Lukas; Hoffmann-Jacobsen, Kerstin

    2017-09-01

    Fluorescence correlation spectroscopy (FCS) measures fluctuations in a (sub-)femtoliter volume to analyze the diffusive behavior of fluorescent particles. This highly sensitive method has proven to be useful for the analysis of dynamic biological systems as well as in chemistry, physics, and material sciences. It is routinely performed with commercial fluorescence microscopes, which provide a confined observation volume by the confocal technique. The evanescent wave of total internal reflectance (TIR) is used in home-built systems to permit a surface sensitive FCS analysis. We present a combined confocal and TIR-FCS setup which uses economic low-power pulsed diode lasers for excitation. Excitation and detection are coupled to time-correlated photon counting hardware. This allows simultaneous fluorescence lifetime and FCS measurements in a surface-sensitive mode. Moreover, the setup supports fluorescence lifetime correlation spectroscopy at surfaces. The excitation can be easily switched between TIR and epi-illumination to compare the surface properties with those in liquid bulk. The capabilities of the presented setup are demonstrated by measuring the diffusion coefficients of a free dye molecule, a labeled polyethylene glycol, and a fluorescent nanoparticle in confocal as well as in TIR-FCS.

  15. [Application of three-dimensional laser scanning-based maxillofacial soft tissue reconstruction in orthodontic treatment].

    Science.gov (United States)

    Tian, Hua; Wu, Bu-ling; Bi, Zhen-yu; Jiao, Pei-feng; Zhao, Wei-dong; Sun, Feng-yang; Xu, Hui-yong; Liu, Yang

    2011-05-01

    To establish a convenient and rapid method for constructing a digital model of the maxillofacial soft tissue based on three-dimensional laser surface scanning to allow direct and accurate observation of the soft tissue changes in the course of orthodontic treatment. The point cloud data of three-dimensional laser scanning of the maxillofacial region were acquired from a healthy woman with Angle Class I occlusion, who maintained a horizontal Frankfort plane during scanning with the scanner placed at a distance of 80 cm. The scanning was repeated twice after wearing the dental cast for an Angle Class I occlusion. The three-dimensional digital model of the maxillofacial soft tissue was constructed based on the point cloud using GeoMagic10.0 software. The high-resolution three-dimensional model of the maxillofacial soft tissue reconstructed allowed accurate observation of the distinct facial anatomical landmarks and represented directly the soft tissue changes in the process of orthodontic treatment by merging the models. Using the analytic tool provided by the software, this model also allowed direct quantitative measurement of the nasolabial angle and the distances from the esthetic plane to the upper lip, labral inferior, and mentolabial sulcus, which were 111.86°, -3.57 mm, -2.54 mm, and 3.95 mm before orthodontic treatment as compared to 114.31°, -2.73 mm, -1.06 mm, and 3.46 mm during treatment, and 116.53°, -0.15 mm, 0.64 mm, and 3.11 mm after the treatment, respectively. Three-dimensional laser surface scanning enables accurate and rapid construction of the digital model of the facial soft tissues, which may provide valuable assistance in orthodontic treatment.

  16. Automatic measuring method of catenary geometric parameters based on laser scanning and imaging

    Science.gov (United States)

    Fu, Luhua; Chang, Songhong; Liu, Changjie

    2018-01-01

    The catenary geometric parameters are important factors that affect the safe operation of the railway. Among them, height of conductor and stagger value are two key parameters. At present, the two parameters are mainly measured by laser distance sensor and angle measuring device with manual aiming method, with low measuring speed and poor efficiency. In order to improve the speed and accuracy of catenary geometric parameters detection, a new automatic measuring method of contact wire's parameters based on laser scanning and imaging is proposed. The DLT method is used to calibrate the parameters of the linear array CCD camera. The direction of the scanning laser beam and the spatial coordinate of the starting point of the beam are calculated by geometric method. Finally, the equation is established using the calibrated parameters and the imaginary coordinates of the imaging point, to solve the spatial coordinate of the measured point on the contact wire, so as to calculate height of conductor and stagger value. Different from the traditional hand-held laser phase measuring method, the new method can achieve measurement of the catenary geometric parameters automatically without manual aiming. Through measurement results, accuracy can reach 2mm.

  17. Clinical diagnosis of fissure caries with conventional and laser-induced fluorescence techniques

    OpenAIRE

    Chu, CH; Lo, ECM; You, DSH

    2010-01-01

    We studied the in vivo validity of dentinal fissure caries diagnosis by visual examination, bitewing radiography, and use of a laser-induced fluorescence device (DIAGNOdent). A total of 144 and second molars with macroscopically intact occlusal surfaces in 41 Chinese young adults were examined visually, by bitewing radiography, and by DIAGNOdent. Visual examination after pit and fissure opening was used as the reference standard. The sensitivity and specificity of detecting caries that had ex...

  18. Time-resolved laser-induced fluorescence in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Moulin, C.; Decambox, P.; Mauchien, P.; Petit, A.

    1995-01-01

    Time-Resolved Laser-Induced Fluorescence (TRLIF) is a very sensitive and selective method that has been used for actinides and lanthanides analysis in the nuclear fuel cycle. This technique has been used in different fields such as in geology, in the Purex process, in the environment, in the medical and in waste storage assessment. Spectroscopic data, limits of detection and results obtained in previously quoted fields are presented. (author)

  19. Composition measurement of bicomponent droplets using laser-induced fluorescence of acetone

    OpenAIRE

    Maqua , C.; Depredurand , V.; Castanet , G.; Wolff , M.; Lemoine , F.

    2007-01-01

    International audience; Commercial fuels are complex mixtures, the evaporation of which remains particularly difficult to model. Experimental characterization of the differential vaporization of the components is a problem that is seldom addressed. In this paper, the evaporation of binary droplets made of ethyl-alcohol and acetone is investigated using a technique of measurement of the droplet composition developed in purpose. This technique exploits the laser induced fluorescence of acetone ...

  20. Non-contact measurement of facial surface vibration patterns during singing by scanning laser Doppler vibrometer.

    Science.gov (United States)

    Kitamura, Tatsuya; Ohtani, Keisuke

    2015-01-01

    This paper presents a method of measuring the vibration patterns on facial surfaces by using a scanning laser Doppler vibrometer (LDV). The surfaces of the face, neck, and body vibrate during phonation and, according to Titze (2001), these vibrations occur when aerodynamic energy is efficiently converted into acoustic energy at the glottis. A vocalist's vibration velocity patterns may therefore indicate his or her phonatory status or singing skills. LDVs enable laser-based non-contact measurement of the vibration velocity and displacement of a certain point on a vibrating object, and scanning LDVs permit multipoint measurements. The benefits of scanning LDVs originate from the facts that they do not affect the vibrations of measured objects and that they can rapidly measure the vibration patterns across planes. A case study is presented herein to demonstrate the method of measuring vibration velocity patterns with a scanning LDV. The objective of the experiment was to measure the vibration velocity differences between the modal and falsetto registers while three professional soprano singers sang sustained vowels at four pitch frequencies. The results suggest that there is a possibility that pitch frequency are correlated with vibration velocity. However, further investigations are necessary to clarify the relationships between vibration velocity patterns and phonation status and singing skills.

  1. Detection of potassium deficiency on palm oil tree (Elaeis guineensis (jacq)) by laser induced fluorescence

    International Nuclear Information System (INIS)

    Diomande, K.; Konate, A.; Krou Adjo, V.; Soro, A.; Ebby, N.; Ballo, K.

    1998-02-01

    The potassium is the main nutrient element which plays a significant role on oil palm tree (Elaeis guineensis (jacq)) production and its resistance to the dry season. One can observe 30% decrease of the production in case of potassium deficiency. The potassium nutrition control of an oil palm tree field is a very important activity and leads to the fertilization policy. The Laser Induced Fluorescence (L.I.F.) is a fast and simple method compared to the classical one, ''Diagnostic Foliaire'', usually used in agronomy. We used the L.I.F. method to detect the oil palm tree stress caused by potassium deficiency, analysing the fluorescence spectrum of the chlorophyll a. We proved that the intensity ratio of the fluorescence spectrum R=F690/F73S is superior to 0.5 when the tree is under stress and its value is around 0.4 in case of intact tree. (author)

  2. Monitoring tissue metabolism via time-resolved laser fluorescence

    Science.gov (United States)

    Maerz, Holger K.; Buchholz, Rainer; Emmrich, Frank; Fink, Frank; Geddes, Clive L.; Pfeifer, Lutz; Raabe, Ferdinand; Marx, Uwe

    1999-05-01

    Most assays for drug screening are monitoring the metabolism of cells by detecting the NADH content, which symbolize its metabolic activity, indirectly. Nowadays, the performance of a LASER enables us to monitor the metabolic state of mammalian cells directly and on-line by using time-resolved autofluorescence detection. Therefore, we developed in combination with tissue engineering, an assay for monitoring minor toxic effects of volatile organic compounds (VOC), which are accused of inducing Sick Building Syndrome (SBS). Furthermore, we used the Laserfluoroscope (LF) for pharmacological studies on human bone marrow in vitro with special interest in chemotherapy simulation. In cancer research and therapy, the effect of chemostatica in vitro in the so-called oncobiogram is being tested; up to now without great success. However, it showed among other things that tissue structure plays a vital role. Consequently, we succeeded in simulating a chemotherapy in vitro on human bone marrow. Furthermore, after tumor ektomy we were able to distinguish between tumoric and its surrounding healthy tissue by using the LF. With its sensitive detection of metabolic changes in tissues the LF enables a wide range of applications in biotechnology, e.g. for quality control in artificial organ engineering or biocompatability testing.

  3. MODELING MAIN BODY OF OVERCROSSING BRIDGE BASED ON VEHICLE-BORNE LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    X. Chen

    2017-09-01

    Full Text Available Vehicle-borne laser scanning (VBLS is widely used to collect urban data for various mapping and modelling systems. This paper proposes a strategy of feature extraction and 3d model reconstruction for main body of overcrossing bridges based on VBLS point clouds. As the bridges usually have a large span, and the clouds data is often affected by obstacles, we have to use round-trip cloud data to avoid missing part. To begin with, pick out the cloud of the bridge body by an interactive clip-box, and group points by scan-line, then sort the points by scanning angle on each scan line. Since the position under the vehicle have a fixed scan-angle, a virtual path can be obtained. Secondly, extract horizontal line segments perpendicular to the virtual path along adjacent scan-lines, and then cluster line segments into long line-strings, which represent the top and bottom edge. Finally, regularize the line-strings and build 3d surface model of the bridge body. Experimental studies have demonstrated its efficiency and accuracy in case of building bridge model. Modelling the stairs at the both end of the bridge will be the direction of the next step.

  4. Modeling Main Body of Overcrossing Bridge Based on Vehicle-Borne Laser Scanning Data

    Science.gov (United States)

    Chen, X.; Chen, M.; Wei, Z.; Zhong, R.

    2017-09-01

    Vehicle-borne laser scanning (VBLS) is widely used to collect urban data for various mapping and modelling systems. This paper proposes a strategy of feature extraction and 3d model reconstruction for main body of overcrossing bridges based on VBLS point clouds. As the bridges usually have a large span, and the clouds data is often affected by obstacles, we have to use round-trip cloud data to avoid missing part. To begin with, pick out the cloud of the bridge body by an interactive clip-box, and group points by scan-line, then sort the points by scanning angle on each scan line. Since the position under the vehicle have a fixed scan-angle, a virtual path can be obtained. Secondly, extract horizontal line segments perpendicular to the virtual path along adjacent scan-lines, and then cluster line segments into long line-strings, which represent the top and bottom edge. Finally, regularize the line-strings and build 3d surface model of the bridge body. Experimental studies have demonstrated its efficiency and accuracy in case of building bridge model. Modelling the stairs at the both end of the bridge will be the direction of the next step.

  5. Laser-induced fluorescence of se, as, and sb in an electrothermal atomizer.

    Science.gov (United States)

    Swart, D J; Ezer, M; Pacquette, H L; Simeonsson, J B

    1998-04-01

    Trace detection of Se, As, and Sb atoms has been performed by electrothermal atomization laser-induced fluorescence (ETA-LIF) approaches. Production of far-UV radiation necessary for excitation of As atoms at 193.696 nm and Se atoms at 196.026 nm was accomplished by stimulated Raman shifting (SRS) of the output of a frequency-doubled dye laser operating near 230 nm. Both wavelengths were obtained as second-order anti-Stokes shifts of the dye laser radiation and provided up to 10 μJ/pulse, which was shown through power dependence studies to be sufficient for saturation in the ETA. An excited-state direct line fluorescence approach using excitation at 206.279 nm was also investigated for the LIF detection of Se. High-sensitivity LIF of Sb atoms was accomplished using 206.833-nm excitation and detection at 259.805 nm. The accuracy of the ETA-LIF approaches was demonstrated by determining the As and Se content of aqueous reference samples. The limits of detection (absolute mass) were 200 fg by ground-state LIF and 150 fg by excited-state direct line fluorescence for Se, 200 fg for As, and 10 fg for Sb; these LODs compare favorably with results reported previously in the literature for ETA-LIF, GFAAS, and ICP-MS methods.

  6. In vitro study of caries detection through sound dentin using a laser fluorescence device, DIAGNOdent.

    Science.gov (United States)

    Iwami, Yukiteru; Shimizu, Ayako; Yamamoto, Hiroko; Hayashi, Mikako; Takeshige, Fumio; Ebisu, Shigeyuki

    2003-02-01

    The objective of this study was to investigate the feasibility of proximal surface caries detection using a laser fluorescence device, DIAGNOdent, through the sound dentin surrounding the cavity wall after removal of occlusal caries. Extracted sound human molars were ground to prepare horizontal and vertical dentin plates 1.4 mm thick. Extracted carious human molars were reduced in thickness horizontally from the occlusal surfaces until exposure of the dentin caries. The dentin plate was placed on the carious tooth. Before and after gradual thinning of the dentin plate from approximately 1.4 mm to 0.2 mm thick, the dentin caries was measured 10 times through the plate by the laser fluorescence device with a cone-shaped tip or a broad tip. When the dentin plate was reduced to less than 0.3 mm thick (using a combination of a horizontal plate and cone-shaped tip) or 0.2 mm thick (using the other combinations), the values measured with the laser fluorescence device were significantly larger than the values before reducing the thickness of the dentin. Based on these results, the device offers potential use as one of the screening tests for proximal surface caries detection through sound dentin when the sound dentin between tip and caries is thin.

  7. Laser-induced fluorescence detection platform for point-of-care testing

    Science.gov (United States)

    Berner, Marcel; Hilbig, Urs; Schubert, Markus B.; Gauglitz, Günter

    2017-08-01

    Point-of-care testing (POCT) devices for continuous low-cost monitoring of critical patient parameters require miniaturized and integrated setups for performing quick high-sensitivity analyses, away from central clinical laboratories. This work presents a novel and promising laser-induced fluorescence platform for measurements in direct optical test formats that leads towards such powerful POCT devices based on fluorescence-labeled immunoassays. Ultimate sensitivity of thin film photodetectors, integrated with microfluidics, and a comprehensive optimization of all system components aim at low-level signal detection in the targeted biosensor application. The setup acquires fluorescence signals from the volume of a microfluidic channel. An innovative sandwiching process forms a flow channel in the microfluidic chips by embedding laser-cut double-sided adhesive tapes. The custom fit of amorphous silicon based photodiode arrays to the geometry of the flow channel enables miniaturization, fully adequate for POCT devices. A free-beam laser excitation with line focus provides excellent alignment stability, allows for easy and reliable swapping of the disposable microfluidic chips, and therewith greatly improves the ease of use of the resulting integrated device. As a proof-of-concept of this novel in-volume measurement approach, the limit of detection for the dye DY636-COOH in pure water as a model fluorophore is examined and found to be 26 nmol l-1 .

  8. Effective Data-Driven Calibration for a Galvanometric Laser Scanning System Using Binocular Stereo Vision.

    Science.gov (United States)

    Tu, Junchao; Zhang, Liyan

    2018-01-12

    A new solution to the problem of galvanometric laser scanning (GLS) system calibration is presented. Under the machine learning framework, we build a single-hidden layer feedforward neural network (SLFN)to represent the GLS system, which takes the digital control signal at the drives of the GLS system as input and the space vector of the corresponding outgoing laser beam as output. The training data set is obtained with the aid of a moving mechanism and a binocular stereo system. The parameters of the SLFN are efficiently solved in a closed form by using extreme learning machine (ELM). By quantitatively analyzing the regression precision with respective to the number of hidden neurons in the SLFN, we demonstrate that the proper number of hidden neurons can be safely chosen from a broad interval to guarantee good generalization performance. Compared to the traditional model-driven calibration, the proposed calibration method does not need a complex modeling process and is more accurate and stable. As the output of the network is the space vectors of the outgoing laser beams, it costs much less training time and can provide a uniform solution to both laser projection and 3D-reconstruction, in contrast with the existing data-driven calibration method which only works for the laser triangulation problem. Calibration experiment, projection experiment and 3D reconstruction experiment are respectively conducted to test the proposed method, and good results are obtained.

  9. Effective Data-Driven Calibration for a Galvanometric Laser Scanning System Using Binocular Stereo Vision

    Directory of Open Access Journals (Sweden)

    Junchao Tu

    2018-01-01

    Full Text Available A new solution to the problem of galvanometric laser scanning (GLS system calibration is presented. Under the machine learning framework, we build a single-hidden layer feedforward neural network (SLFN)to represent the GLS system, which takes the digital control signal at the drives of the GLS system as input and the space vector of the corresponding outgoing laser beam as output. The training data set is obtained with the aid of a moving mechanism and a binocular stereo system. The parameters of the SLFN are efficiently solved in a closed form by using extreme learning machine (ELM. By quantitatively analyzing the regression precision with respective to the number of hidden neurons in the SLFN, we demonstrate that the proper number of hidden neurons can be safely chosen from a broad interval to guarantee good generalization performance. Compared to the traditional model-driven calibration, the proposed calibration method does not need a complex modeling process and is more accurate and stable. As the output of the network is the space vectors of the outgoing laser beams, it costs much less training time and can provide a uniform solution to both laser projection and 3D-reconstruction, in contrast with the existing data-driven calibration method which only works for the laser triangulation problem. Calibration experiment, projection experiment and 3D reconstruction experiment are respectively conducted to test the proposed method, and good results are obtained.

  10. Does Pattern Scan Laser (PASCAL) photocoagulation really induce less VEGF expression in murine retina than conventional laser treatment?

    Science.gov (United States)

    Konac, Ece; Sonmez, Kenan; Bahcelioglu, Meltem; Kaplanoglu, Gulnur Take; Varol, Nuray; Sarac, Gulce Naz; Ozcan, P Yasin

    2014-10-01

    To investigate the differences in the mRNA and protein expression levels of vascular endothelial growth factor (VEGF) in murine retina between mice subjected to conventional laser (AG) and those subjected to Pattern Scan Laser (PASCAL) system. Male C57BL/6 mice were randomly assigned to one of three groups: Group 1 (G1) receiving retinal scatter laser photocoagulation using with AG photocoagulator (n=16), Group 2 (G2) receiving retinal scatter laser photocoagulation using with PASCAL (n=16) and Group 3 (G3) served as an untreated control group (n=6). Molecular and morphological analyses of VEGF were performed on days 1, 2 and 5 by ELISA, real-time PCR and immuno-histochemical analysis. In samples which underwent AG (G1), when compared with the control group (G3), VEGF mRNA level increased 2.4 folds on day 2, whereas it decreased on day 5 (p□0.001). In samples which underwent PASCAL (G2), on the other hand, VEGF mRNA level increased 1.8 folds on day 1 and 2.2 folds on day 5 when compared with the control group (G3). In samples which underwent AG (G1), when compared with the control group (G3), VEGF protein level increased significantly on day 2, whereas it decreased on day 5 (p□0.001). In group G2, the VEGF levels in the sensory retina significantly increased as compared to control groups at both 2 and 5 days after laser photocoagulation using PASCAL laser (p=0.012, both time points). The peak expressions of VEGF protein in samples which underwent PASCAL and conventional laser were found on day 5 and day 2 respectively. In retinas of PASCAL-treated mice, VEGF immunoreactivity gradually increased during the 5-day follow-up. However, in argon laser group, the strongest VEGF immunoreactivity was detected on day 2, then started to decrease on day 5. In summary, the expression of VEGF protein and mRNA gradually increase during a 5-day follow-up period in PASCAL-treated mouse eyes, whereas in AG group they reach their peak levels on the second day of follow-up and

  11. Novel 755-nm diode laser vs. conventional 755-nm scanned alexandrite laser: Side-by-side comparison pilot study for thorax and axillary hair removal.

    Science.gov (United States)

    Paasch, Uwe; Wagner, Justinus A; Paasch, Hartmut W

    2015-01-01

    Alexandrite (755 nm) and diode lasers (800-810 nm) are commonly used for hair removal. The alexandrite laser technology is somewhat cumbersome whereas new diode lasers are more robust. Recently, alexandrite-like 755 nm wavelength diodes became available. To compare the efficacy, tolerability, and subject satisfaction of a 755 nm diode laser operated in conventional (HR) and non-conventional in-motion (SHR) modes with a conventional scanned alexandrite 755 nm laser for chest and axillary hair removal. A prospective, single-center, proof of principle study was designed to evaluate the safety, efficacy and handling of a 755 nm diode laser system in comparison to a standard alexandrite 755 nm scanning hair removal laser. The new 755 nm diode is suitable to be used in SHR and HR mode and has been tested for its safety, efficacy and handling in a volunteer with success. Overall, both systems showed a high efficacy in hair reduction (88.8% 755 nm diode laser vs. 77.7% 755 nm alexandrite laser). Also, during the study period, no severe adverse effects were reported. The new 755 nm diode laser is as effective and safe as the traditional 755 nm alexandrite laser. Additionally, treatment with the 755 nm diode laser with HR and SHR modes was found to be less painful.

  12. Selective Removal of Residual Orthodontic Composite Using a Rapidly Scanned Carbon Dioxide Laser with Spectral Feedback

    Science.gov (United States)

    Hirasuna, Krista

    Background and Objective: Excessive heat accumulation within the tooth, incomplete removal of composite, and variable damage to the enamel are shortcomings of using conventional burs to remove residual orthodontic composite after debonding fixed appliances. The objective of this study was to determine if composite could be selectively removed from the enamel surface using a rapidly scanned carbon dioxide laser controlled by spectral feedback. Materials and Methods: A carbon dioxide laser operating at a wavelength of 9.3 microm with a pulse duration of 10-15 micros and a pulse repetition rate of ˜ 200 Hz was used to selectively remove composite from the buccal surfaces of 21 extracted teeth. GrenGloo(TM) composite was used to better visualize residual composite and the amount of enamel lost was measured with optical microscopy. A spectral feedback system utilizing a miniature spectrometer was used to control the laser scanning system. Pulpal temperature measurements were performed during composite removal to determine if there was excessive heat accumulation. Results: The amount of enamel lost averaged 22.7microm +/- 8.9 and 25.3 microm +/- 9.4 for removal at 3.8 and 4.2 J/cm2, respectively. An average maximum temperature rise of 1.9°C +/- 1.5 was recorded, with no teeth approaching the critical value of 5.5°C. The average time of composite removal was 19.3 +/- 4.1 seconds. Conclusions: Residual orthodontic composite can be rapidly removed from the tooth surface using a rapidly scanned CO2 laser with spectral feedback, with minimal temperature rise within the pulp and with minimal damage to the underlying enamel surface.

  13. FROM THE CONTINUOS TO THE DISCRETE MODEL: A LASER SCANNING APPLICATION TO CONSERVATION PROJECTS

    Directory of Open Access Journals (Sweden)

    A. Cardaci

    2012-09-01

    Full Text Available This paper aims to demonstrate the usage of laser scanning (in particular through a methodology based on the integrated use of the software "FARO© Scene" and "GEXCEL JRC-3D Reconstructor" as a valid alternative to traditional surveying techniques, especially when finalized to the restoration and conservation repair of historical buildings. The need to recreate the complex and often irregular shapes of the ancient architecture, by acting quickly and also being accurate, as well as the subsequent implementation of FEM (Finite Element Method for structural analysis, have made nowadays the laser scanning survey a very useful technique. The point cloud obtained by laser scanning can be a flexible tool for every need; not a finished product, but a huge database from which it is possible to extract different information at different times. The use of numerical methods in data processing allows wide opportunities of further investigations starting from the fitting equations. The numerical model lends by itself to the possibility of usage in many applications, such as modelization and structure analysis software. This paper presents the case study of the Church of the Assumption and Saint Michael the Archangel, located in Borgo di Terzo (Italy, a magnificent 18th century's building that presented several structural problems like as the overturning of the façade, the cracking of part of the vaulted ceiling. The survey, carried out by laser scanner (FARO© Photon 120 allowed the reconstruction of the exact geometry of the church, offering the basis for performing structural analysis supported by a realistic model (and not an idealized regular one, useful also in the design of repair interventions.

  14. Erosion rate diagnostics in ion thrusters using laser-induced fluorescence

    Science.gov (United States)

    Gaeta, C. J.; Matossian, J. N.; Turley, R. S.; Beattie, J. R.; Williams, J. D.; Williamson, W. S.

    1993-01-01

    We have used laser-induced fluorescence (LIF) to monitor the charge-exchange ion erosion of the molybdenum accelerator electrode in ion thrusters. This real-time, nonintrusive method was implemented by operating a 30cm-diam ring-cusp thruster using xenon propellant. With the thruster operating at a total power of 5 kW, laser radiation at a wavelength of 390 nm (corresponding to a ground state atomic transition of molybdenum) was directed through the extracted ion beam adjacent to the downstream surface of the molybdenum accelerator electrode. Molybdenum atoms, sputtered from this surface as a result of charge-exchange ion erosion, were excited by the laser radiation. The intensity of the laser-induced fluorescence radiation, which is proportional to the sputter rate of the molybdenum atoms, was measured and correlated with variations in thruster operating conditions such as accelerator electrode voltage, accelerator electrode current, and test facility background pressure. We also demonstrated that the LIF technique has sufficient sensitivity and spatial resolution to evaluate accelerator electrode lifetime in ground-based test facilities.

  15. Violet diode laser-induced chlorophyll fluorescence: a tool for assessing mosaic disease severity in cassava (Manihot esculenta Crantz) cultivars.

    Science.gov (United States)

    Anderson, Benjamin; Eghan, Moses J; Asare-Bediako, Elvis; Buah-Bassuah, Paul K

    2012-01-01

    Violet diode laser-induced chlorophyll fluorescence was used in agronomical assessment (disease severity and average yield per plant). Because cassava (Manihot esculenta Crantz) is of economic importance, improved cultivars with various levels of affinity for cassava mosaic disease were investigated. Fluorescence data correlated with cassava mosaic disease severity levels and with the average yield per plant.

  16. Homogenization optics to improve detectability of a fluorescence response to a single laser pulse: Detection of feces on apples

    Science.gov (United States)

    Fecal contamination of produce is a known food safety risk. Measuring fluorescence responses to UV excitation is an established method for detecting such contamination. One measurement system utilizes a pulsed UV laser to induce a fluorescence response from fecal material and a gated intensified cam...

  17. Sensitive detection of protein and miRNA cancer biomarkers using silicon-based photonic crystals and a resonance coupling laser scanning platform.

    Science.gov (United States)

    George, Sherine; Chaudhery, Vikram; Lu, Meng; Takagi, Miki; Amro, Nabil; Pokhriyal, Anusha; Tan, Yafang; Ferreira, Placid; Cunningham, Brian T

    2013-10-21

    Enhancement of the fluorescent output of surface-based fluorescence assays by performing them upon nanostructured photonic crystal (PC) surfaces has been demonstrated to increase signal intensities by >8000×. Using the multiplicative effects of optical resonant coupling to the PC in increasing the electric field intensity experienced by fluorescent labels ("enhanced excitation") and the spatially biased funneling of fluorophore emissions through coupling to PC resonances ("enhanced extraction"), PC enhanced fluorescence (PCEF) can be adapted to reduce the limits of detection of disease biomarker assays, and to reduce the size and cost of high sensitivity detection instrumentation. In this work, we demonstrate the first silicon-based PCEF detection platform for multiplexed biomarker assay. The sensor in this platform is a silicon-based PC structure, comprised of a SiO2 grating that is overcoated with a thin film of high refractive index TiO2 and is produced in a semiconductor foundry for low cost, uniform, and reproducible manufacturing. The compact detection instrument that completes this platform was designed to efficiently couple fluorescence excitation from a semiconductor laser to the resonant optical modes of the PC, resulting in elevated electric field strength that is highly concentrated within the region <100 nm from the PC surface. This instrument utilizes a cylindrically focused line to scan a microarray in <1 min. To demonstrate the capabilities of this sensor-detector platform, microspot fluorescent sandwich immunoassays using secondary antibodies labeled with Cy5 for two cancer biomarkers (TNF-α and IL-3) were performed. Biomarkers were detected at concentrations as low as 0.1 pM. In a fluorescent microarray for detection of a breast cancer miRNA biomarker miR-21, the miRNA was detectable at a concentration of 0.6 pM.

  18. High sensitivity detection of selenium by laser excited atomic fluorescence spectrometry using electrothermal atomization

    International Nuclear Information System (INIS)

    Heitmann, U.; Hese, A.; Schoknecht, G.; Gries, W.

    1995-01-01

    The high sensitivity detection of the trace element selenium is reported. The analytical method applied is Laser Excited Atomic Fluorescence Spectrometry using Electrothermal Atomization within a graphite furnace atomizer. For the production of tunable laser radiation in the VUV spectral region a laser system was developed which consists of two dye lasers pumped by a Nd:YAG laser. The laser radiations are subsequently frequency doubled and sum frequency mixed by nonlinear optical KDP or BBO crystals, respectively. The system works with a repetition rate of 20 Hz and provides output energies of up to 100 μJ in the VUV at a pulse duration of 5 ns. The analytical investigations were focused on the detection of selenium in aqueous solutions and samples of human whole blood. From measurements on aqueous standards detection limits of 1.5 ng/l for selenium were obtained, with corresponding absolute detected masses of only 15 fg. The linear dynamic range spanned six orders of magnitude and good precision was achieved. In case of human whole blood samples the recovery was found to be within the range of 96% to 104%. The determination of the selenium content yielded medians of [119.5 ± 17.3] μg/l for 200 frozen blood samples taken in 1988 and [109.1 ± 15.6] μg/l for 103 fresh blood samples. (author)

  19. High repetition rate laser induced fluorescence applied to Surfatron Induced Plasmas

    Science.gov (United States)

    van der Mullen, J. J. A. M.; Palomares, J. M.; Carbone, E. A. D.; Graef, W.; Hübner, S.

    2012-05-01

    The reaction kinetics in the excitation space of Ar and the conversion space of Ar-molecule mixtures are explored using a combination of high rep-rate YAG-Dye laser systems with a well defined and easily controllable Surfatron Induced Plasma set-up. Applying the method of Saturation Time Resolved Laser Induced Fluorescence (SaTiRe-LIF), we could trace excitation and conversion channels and determine rates of electron and heavy particle excitation kinetics. The time resolved density disturbances observed in the Ar excitation space, which are initiated by the laser, reveal the excitation channels and corresponding rates; responses of the molecular radiation in Ar-molecule mixtures corresponds to the presence of conversion processes induced by heavy particle excitation kinetics.

  20. Identification Of Natural Dyes On Archaeological Textile Objects Using Laser Induced Fluorescent Technique

    International Nuclear Information System (INIS)

    Abdel-Kareem, O.; Eltokhy, A.; Harith, M. A.

    2011-01-01

    This study aims to evaluate the use of Laser Fluorescent as a non-destructive technique for identification of natural dyes on archaeological textile objects. In this study wool textile samples were dyed with 10 natural dyes such as cochineal, cutch, henna, indigo, Lac, madder, safflower, saffron, sumac and turmeric. These dyes common present on archaeological textile objects to be used as standard dyed textile samples. These selected natural dyes will be used as known references that can be used a guide to identify unknown archaeological dyes. The dyed textile samples were investigated with laser radiation in different wavelengths to detect the best wavelengths for identification each dye. This study confirms that Laser Florescent is very useful and a rapid technique can be used as a non-destructive technique for identification of natural dyes on archaeological textile objects. The results obtained with this study can be a guide for all conservators in identification of natural organic dyes on archaeological textile objects.

  1. Identification Of Natural Dyes On Archaeological Textile Objects Using Laser Induced Fluorescent Technique

    Science.gov (United States)

    Abdel-Kareem, O.; Eltokhy, A.; Harith, M. A.

    2011-09-01

    This study aims to evaluate the use of Laser Fluorescent as a non-destructive technique for identification of natural dyes on archaeological textile objects. In this study wool textile samples were dyed with 10 natural dyes such as cochineal, cutch, henna, indigo, Lac, madder, safflower, saffron, sumac and turmeric. These dyes common present on archaeological textile objects to be used as standard dyed textile samples. These selected natural dyes will be used as known references that can be used a guide to identify unknown archaeological dyes. The dyed textile samples were investigated with laser radiation in different wavelengths to detect the best wavelengths for identification each dye. This study confirms that Laser Florescent is very useful and a rapid technique can be used as a non-destructive technique for identification of natural dyes on archaeological textile objects. The results obtained with this study can be a guide for all conservators in identification of natural organic dyes on archaeological textile objects.

  2. Parallel ion flow velocity measurement using laser induced fluorescence method in an electron cyclotron resonance plasma

    International Nuclear Information System (INIS)

    Yoshimura, Shinji; Okamoto, Atsushi; Terasaka, Kenichiro; Ogiwara, Kohei; Tanaka, Masayoshi Y.; Aramaki, Mitsutoshi

    2010-01-01

    Parallel ion flow velocity along a magnetic field has been measured using a laser induced fluorescence (LIF) method in an electron cyclotron resonance (ECR) argon plasma with a weakly-diverging magnetic field. To measure parallel flow velocity in a cylindrical plasma using the LIF method, the laser beam should be injected along device axis; however, the reflection of the incident beam causes interference between the LIF emission of the incident and reflected beams. Here we present a method of quasi-parallel laser injection at a small angle, which utilizes the reflected beam as well as the incident beam to obtain the parallel ion flow velocity. Using this method, we observed an increase in parallel ion flow velocity along the magnetic field. The acceleration mechanism is briefly discussed on the basis of the ion fluid model. (author)

  3. 3D camera assisted fully automated calibration of scanning laser Doppler vibrometers

    International Nuclear Information System (INIS)

    Sels, Seppe; Ribbens, Bart; Mertens, Luc; Vanlanduit, Steve

    2016-01-01

    Scanning laser Doppler vibrometers (LDV) are used to measure full-field vibration shapes of products and structures. In most commercially available scanning laser Doppler vibrometer systems the user manually draws a grid of measurement locations on a 2D camera image of the product. The determination of the correct physical measurement locations can be a time consuming and diffcult task. In this paper we present a new methodology for product testing and quality control that integrates 3D imaging techniques with vibration measurements. This procedure allows to test prototypes in a shorter period because physical measurements locations will be located automatically. The proposed methodology uses a 3D time-of-flight camera to measure the location and orientation of the test-object. The 3D image of the time-of-flight camera is then matched with the 3D-CAD model of the object in which measurement locations are pre-defined. A time of flight camera operates strictly in the near infrared spectrum. To improve the signal to noise ratio in the time-of-flight measurement, a time-of-flight camera uses a band filter. As a result of this filter, the laser spot of most laser vibrometers is invisible in the time-of-flight image. Therefore a 2D RGB-camera is used to find the laser-spot of the vibrometer. The laser spot is matched to the 3D image obtained by the time-of-flight camera. Next an automatic calibration procedure is used to aim the laser at the (pre)defined locations. Another benefit from this methodology is that it incorporates automatic mapping between a CAD model and the vibration measurements. This mapping can be used to visualize measurements directly on a 3D CAD model. Secondly the orientation of the CAD model is known with respect to the laser beam. This information can be used to find the direction of the measured vibration relatively to the surface of the object. With this direction, the vibration measurements can be compared more precisely with numerical

  4. Cooling and Laser-Induced Fluorescence of Electronically-Excited He2 in a Supersonic Microcavity Plasma Jet

    Science.gov (United States)

    Su, Rui; Mironov, Andrey; Houlahan, Thomas, Jr.; Eden, J. Gary; LaboratoryOptical Physics; Engineering Team

    2016-09-01

    Laser-induced fluorescence (LIF) resulting from transitions between different electronic states of helium dimers generated within a microcavity plasma jet was studied with rotational resolution. In particular, the d3Σu+ , e3Πg and f3Σu+ states, all having electronic energies above 24 eV, are populated by a microplasma in 4 bar of helium gas and rotationally cooled through supersonic expansion. Analysis of two dimensional maps (spectrograms) of dimer emission spectra as a function of distance from the nozzle orifice indicates collisional coupling during the expansion between the lowest rotational levels of the e3Πg , f3Σu+ states and high rotational levels (around N=11) of the d3Σu+ state (all of which are in the v = 0 vibrational state). In an attempt to verify the coupling, a scanning dye laser (centered near 596 nm) pumps the b3Πg -> f3Σu+ transition of the molecule several hundred micrometers downstream of the nozzle. As a result, the emission intensities of relevant rotational lines are observed to be enhanced. This research shows the potential of utilizing microcavity plasma jets as a tool to study and manipulate the collisional dynamics of highly-excited diatomic molecules.

  5. A LOW BUDGET MOBILE LASER SCANNING SOLUTION USING ON BOARD SENSORS AND FIELD BUS SYSTEMS OF TODAY'S CONSUMER AUTOMOBILES

    Directory of Open Access Journals (Sweden)

    D. M. M. Vock

    2012-09-01

    Full Text Available Mobile laser scanning systems (MLS offer a great potential for acquiring detailed point cloud data of urban and suburban surroundings with minimum effort. In this paper a new solution for MLSs is presented, requiring solely a combination of a profile laser scanning device and systems that are included in today's serialized end consumer vehicles. While today's mobile laser scan systems require different and expensive additional hardware that needs to be mounted onto the vehicle, the devices included within vehicle electronics offer good alternatives without additional costs.The actual scan consists of a continuous profile scan together with information gathered from on-board sensor modules. In a post- processing step, the sensor data is used to reconstruct the car's trajectory for the period of the scan and, based on this information, the track of the scan device for every measured laser pixel. Synchronization of pixel data and vehicle movement is realized via a timestamp signal which is transmitted to the car's field bus system and the scan device. To generate the final point cloud scenario, the trajectory is interpolated for every single scan point and used to convert its local position within the profile into the global coordinate system (Fig.1, Left.

  6. Development of laser-induced fluorescence for precombustion diagnostics in spark-ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Neij, H.

    1998-11-01

    Motivated by a desire to understand and optimize combustion in spark-ignition (SI) engines, laser techniques have been developed for measurement of fuel and residual gas, respectively, in the precombustion mixture of an operating SI engine. The primary objective was to obtain two-dimensional, quantitative data in the vicinity of the spark gap at the time of ignition. A laser-induced fluorescence (LIF) technique was developed for fuel visualization in engine environments. Since the fluorescence signal from any commercial gasoline fuel would be unknown to its origin, with an unpredictable dependence on collisional partners, pressure and temperature, a non-fluorescent base fuel - isooctane - was used. For LIF detection, a fluorescent species was added to the fuel. An additive not commonly used in this context - 3-pentanone - was chosen based on its suitable vaporization characteristics and fluorescent properties. The LIF technique was applied to an optically accessible research engine. By calibration, the fluorescence signal from the additive was converted to fuel-to-air equivalence ratio ({phi}). The accuracy and precision of the acquired data were assessed. A statistical evaluation revealed that the spatially averaged equivalence ratio around the spark plug had a significant impact on the combustion event. The strong correlation between these two quantities suggested that the early combustion was sensitive to large-scale inhomogeneities in the precombustion mixture. A similar LIF technique, using acetone as a fluorescent additive in methane, was applied to a combustion cell for ion current evaluation. The local equivalence ratio around the spark gap at the time of ignition was extracted from LIF data. Useful relations were identified between different ion current parameters and the local equivalence ratio, although the impact of the flow field, the fuel type, and the electrode geometry were identified as areas for future research. A novel fuel - dimethyl ether (DME

  7. Scanning electron microscopy and fluorescent in situ hybridization of experimental Brachyspira (Serpulina) pilosicoli infection in growing pigs

    DEFF Research Database (Denmark)

    Jensen, Tim Kåre; Møller, Kristian; Boye, Mette

    2000-01-01

    Two groups of six 8-week-old pigs were challenged with 1X10(9) cfu Brachyspira (Serpulina) pilosicoli or Serpulina intermedia daily for 3 consecutive days to study the pathology of porcine colonic spirochetosis by scanning electron microscopy (SEM) and fluorescent in situ hybridization (FISH......) with oligonucleotide probes targeting ribosomal RNA specific for B. pilosicoli and the genus Brachyspira/Serpulina. Six pigs served as noninoculated controls. The animals were euthanatized successively between postinoculation days 14 and 24. B. pilosicoli was reisolated in feces from all of the inoculated pigs...

  8. Comparison of visual, impedance spectroscopy and laser fluorescence methods in detecting early carious lesions on occlusal surfaces

    Directory of Open Access Journals (Sweden)

    Chalas Renata

    2014-06-01

    Full Text Available The diagnostic management is a very important and integral part of the entire treatment process and has a direct influence on the decision-taking on the choice of the most appropriate form of therapy consistent with current knowledge. Knowledge of the morphology of hard dental tissues lesions has led to the development of quantitative methods for diagnosis and monitoring of dental caries, which enabled the implementation of appropriate treatments aimed at repairing than replacing damaged tissue. The aim of the study was to compare selected diagnostic methods: visual (ICDAS, impedance spectroscopy (CarieScan PRO and laser fluorescence (Diagnodent Pen in detecting caries in grooves on the chewing surfaces of molars and premolars. The obtained results indicated a high concordance of measurements performed with the Diagnodent Pen with the results of visual examination and a lower compliance of visual examination with the results obtained using the CarieScan PRO. A combination of visual and tactile method with tests using advanced technology provides greater opportunity to confirm the diagnosis of carious lesions requiring medical intervention.

  9. 3D maxillofacial soft-tissue model in laser scanned head

    Science.gov (United States)

    Liang, Haidong; Hughes, Steven

    1998-05-01

    The purpose of this study is to incorporate thickness data into a soft tissue model in a laser scanned head data base, for use in FEA modeling of the behavior of the soft tissue layer under mechanical loads. Using a magnetic-based, spatial acquisition system (Polhemus) into which is incorporated an ultrasound sensor the position and orientation of tissue thickness vectors are obtained. By combining this with 3D high resolution head shape data from our laser scanner, a model of the head complete with soft tissue thickness is to be developed. We have implemented an initial version of software for the integration of laser scanning and facial soft tissue thickness measurement. The package displays facial images and performs basic imaging processing. The co-ordinate systems of the two methods are matched with the help of markers fixed on known head landmarks and a 3D digitiser (Polhemus). The computed source locations can be instantly superimposed on the facial images during the analysis.

  10. System to measure contrast-sensitivity function with a scanning-laser ophthalmoscope

    Science.gov (United States)

    Frambach, Donald A.; Sebag, Jerry; Lawton, Terry; Sadun, Alfredo

    1994-06-01

    A scanning laser ophthalmoscope (SLO) employs an extremely low power laser that is focused to a 10 micron spot on the human retina and scanned across the retina at the same rate and pattern that an electron beam travels across a television screen. An image is acquired by measuring the retina's reflectance along each raster. An acousto-optic modulator, in the path of the laser beam, can be used to write targets directly onto the retina. since the SLO can project targets onto the retina while simultaneously viewing the retina, retinal function at specific locations can be unambiguously assessed. We developed software so that sine wave contrast sensitivity gratings were projected onto subjects' retinas with contrasts ranging from 0 to 63.5%. Subjects determined whether the gratings tilted 45 degree(s) to the right or 45 degree(s) to the left. A staircase protocol using 6 reversals was employed to determine contrast sensitivity at each spatial frequency. In early work with the system, 16 eyes of 11 normal subjects were tested. For 8 eyes the intraclass correlation coefficient of reliability was 0.85. This system yields reproducible measures of contrast sensitivity. It may have advantages over other methods to measure contrast sensitivity because the location of tested retina can be unambiguously assessed and illumination levels from the instrument directly measured and controlled. In addition, the small entrance pupil of the SLO can reduce the effects of cataracts measurements of contrast sensitivity.

  11. Polarization modulation laser scanning microscopy: A powerful tool to image molecular orientation and order

    Science.gov (United States)

    Gupta, Vinay K.; Kornfield, Julia A.

    1994-09-01

    To image the orientational order in a broad class of biological and manufactured materials, a new microscope has been developed that integrates laser scanning microscopy with polarization modulation polarimetry. Polarimetry allows quantitative characterization of the molecular orientation and the degree of order through characterization of optical anisotropy. Combined with laser scanning microscopy, it is used here to image the anisotropy with high spatial resolution, sensitivity, and speed. The design of the microscope is presented; and the vast improvement in sensitivity achieved using PM-LSM over conventional polarization microscopy is illustrated by imaging the linear dichroism of ultrathin Langmuir-Blodgett polymer films. PM-LSM allows imaging of the magnitude and orientation of linear dichroism in films as thin as three molecular layers (˜66 Å) at high resolution by rastering a diffraction limited spot of laser light across the sample. The rate of image acquisition is over 2000 pixels/s, two to three orders of magnitude faster than the previous methods of imaging optical anisotropy.

  12. Additive Manufacturing of Nickel-Base Superalloy IN100 Through Scanning Laser Epitaxy

    Science.gov (United States)

    Basak, Amrita; Das, Suman

    2018-01-01

    Scanning laser epitaxy (SLE) is a laser powder bed fusion (LPBF)-based additive manufacturing process that uses a high-power laser to consolidate metal powders facilitating the fabrication of three-dimensional objects. In the present study, SLE is used to produce samples of IN100, a high-γ' non-weldable nickel-base superalloy on similar chemistry substrates. A thorough analysis is performed using various advanced material characterization techniques such as high-resolution optical microscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy, and Vickers microhardness measurements to characterize and compare the quality of the SLE-fabricated IN100 deposits with the investment cast IN100 substrates. The results show that the IN100 deposits have a finer γ/γ' microstructure, weaker elemental segregation, and higher microhardness compared with the substrate. Through this study, it is demonstrated that the SLE process has tremendous potential in the repair and manufacture of gas turbine hot-section components.

  13. High Heat Flux Interactions and Tritium Removal from Plasma Facing Components by a Scanning Laser

    Energy Technology Data Exchange (ETDEWEB)

    C.H. Skinner; C.A. Gentile; A. Hassanein

    2002-01-28

    A new technique for studying high heat flux interactions with plasma facing components is presented. The beam from a continuous wave 300 W neodymium laser was focused to 80 W/mm2 and scanned at high speed over the surface of carbon tiles. These tiles were previously used in the TFTR [Tokamak Fusion Test Reactor] inner limiter and have a surface layer of amorphous hydrogenated carbon that was codeposited during plasma operations. Laser scanning released up to 84% of the codeposited tritium. The temperature rise of the codeposit on the tiles was significantly higher than that of the manufactured material. In one experiment, the codeposit surface temperature rose to 1,770 C while for the same conditions, the manufactured surface increased to only 1,080 C. The peak temperature did not follow the usual square-root dependence on heat pulse duration. Durations of order 100 ms resulted in brittle destruction and material loss from the surface, while a duration of approximately 10 ms showed minimal change. A digital microscope imaged the codeposit before, during, and after the interaction with the laser and revealed hot spots on a 100-micron scale. These results will be compared to analytic modeling and are relevant to the response of plasma facing components to disruptions and vertical displacement events (VDEs) in next-step magnetic fusion devices.

  14. Laser-line scanning speckle reduction based on a one-dimensional beam homogenizer

    Science.gov (United States)

    Nelsen, B.; Jacobs, P.; Hartmann, P.

    2017-06-01

    Laser-line scanners have become ubiquitous in many forms of automation and measurement systems. Despite this fact, these systems are still susceptible to speckle or interference on rough scattering surfaces. Many scanning systems must be calibrated to the material being analyzed to obtain their full potential. In general, post-processing algorithms are used in most modern line-scanning devices in order to smooth out speckle and enhance the resolution through sub-pixel interpolation. However, these post-processing techniques come at a cost of increased CPU time and a subsequent decrease in bandwidth and resolution. in this paper, a low-cost, high-resolution solution to generating speckle-free sharply focused laser lines is presented. The key to this technique relies on only removing the spatial coherence in one dimension using a 1-D cylindrical lens array as a beam homogenizer. This beam homogenizer is then wrapped around and rotated about a central axis in order to remove the temporal component on the laser's coherence. Since the plane-wave-like behavior is maintained along one dimension, this beam can still be sharply focused to a line. however, the spatial coherence and temporal coherence are reduced to the point that speckle is minimally visible.

  15. Scanning laser-line source technique for nondestructive evaluation of cracks in human teeth.

    Science.gov (United States)

    Sun, Kaihua; Yuan, Ling; Shen, Zhonghua; Xu, Zhihong; Zhu, Qingping; Ni, Xiaowu; Lu, Jian

    2014-04-10

    This paper describes the first application of a remote nondestructive laser ultrasonic (LU) system for clinical diagnosis of cracks in human teeth, to our knowledge. It performs non-contact cracks detection on small-dimension teeth samples. Two extracted teeth with different types of cracks (cracked tooth and craze lines), which have different crack depths, are used as experimental samples. A series of ultrasonic waves were generated by a scanning laser-line source technique and detected with a laser-Doppler vibrometer on the two samples. The B-scan images and peak-to-peak amplitude variation curves of surface acoustic waves were obtained for evaluating the cracks' position and depth. The simulation results calculated by finite element method were combined with the experimental results for accurately measuring the depth of crack. The results demonstrate that this LU system has been successfully applied on crack evaluation of human teeth. And as a remote, nondestructive technique, it has great potential for early in vivo diagnosis of cracked tooth and even the future clinical dental tests.

  16. Fabrication of SLM NiTi Shape Memory Alloy via Repetitive Laser Scanning

    Science.gov (United States)

    Khoo, Zhong Xun; Liu, Yong; Low, Zhi Hong; An, Jia; Chua, Chee Kai; Leong, Kah Fai

    2018-01-01

    Additive manufacturing has the potential to overcome the poor machinability of NiTi shape-memory alloy in fabricating smart structures of complex geometry. In recent years, a number of research activities on selective laser melting (SLM) of NiTi have been carried out to explore the optimal parameters for producing SLM NiTi with the desired phase transformation characteristics and shape-memory properties. Different effects of energy density and processing parameters on the properties of SLM NiTi were reported. In this research, a new approach—repetitive laser scanning—is introduced to meet these objectives as well. The results suggested that the laser absorptivity and heat conductivity of materials before and after the first scan significantly influence the final properties of SLM NiTi. With carefully controlled repetitive scanning process, the fabricated samples have demonstrated shape-memory effect of as high as 5.11% (with an average value of 4.61%) and exhibited comparable transformation characteristics as the NiTi powder used. These results suggest the potential for fabricating complex NiTi structures with similar properties to that of the conventionally produced NiTi parts.

  17. High Heat Flux Interactions and Tritium Removal from Plasma Facing Components by a Scanning Laser

    International Nuclear Information System (INIS)

    Skinner, C.H.; Gentile, C.A.; Hassanein, A.

    2002-01-01

    A new technique for studying high heat flux interactions with plasma facing components is presented. The beam from a continuous wave 300 W neodymium laser was focused to 80 W/mm2 and scanned at high speed over the surface of carbon tiles. These tiles were previously used in the TFTR [Tokamak Fusion Test Reactor] inner limiter and have a surface layer of amorphous hydrogenated carbon that was codeposited during plasma operations. Laser scanning released up to 84% of the codeposited tritium. The temperature rise of the codeposit on the tiles was significantly higher than that of the manufactured material. In one experiment, the codeposit surface temperature rose to 1,770 C while for the same conditions, the manufactured surface increased to only 1,080 C. The peak temperature did not follow the usual square-root dependence on heat pulse duration. Durations of order 100 ms resulted in brittle destruction and material loss from the surface, while a duration of approximately 10 ms showed minimal change. A digital microscope imaged the codeposit before, during, and after the interaction with the laser and revealed hot spots on a 100-micron scale. These results will be compared to analytic modeling and are relevant to the response of plasma facing components to disruptions and vertical displacement events (VDEs) in next-step magnetic fusion devices

  18. Ar+ beam etched Ti:sapphire rib waveguides: a route for the development of broadband fluorescence and channel laser sources

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; May-Smith, T.C.; Eason, R.W.; Pollnau, Markus

    Ar+-beam-milled rib waveguides were fabricated in pulsed-laser-deposited Ti:sapphire films and overgrown by a 5 μm thick sapphire layer to further reduce losses. They show broadband single transverse mode fluorescence emission and the potential for the development of laser sources.

  19. Intercomparison of Terrestrial Laser Scanning Instruments for Assessing Forested Ecosystems: A Brisbane Field Experiment

    Science.gov (United States)

    Armston, J.; Newnham, G.; Strahler, A. H.; Schaaf, C.; Danson, M.; Gaulton, R.; Zhang, Z.; Disney, M.; Sparrow, B.; Phinn, S. R.; Schaefer, M.; Burt, A.; Counter, S.; Erb, A.; Goodwin, N.; Hancock, S.; Howe, G.; Johansen, K.; Li, Z.; Lollback, G.; Martel, J.; Muir, J.; Paynter, I.; Saenz, E.; Scarth, P.; Tindall, D.; Walker, L.; Witte, C.; Woodgate, W.; Wu, S.

    2013-12-01

    During 28th July - 3rd August, 2013, an international group of researchers brought five terrestrial laser scanners (TLS) to long-term monitoring plots in three eucalyptus-dominated woodland sites near Brisbane, Queensland, Australia, to acquire scans at common locations for calibration and intercomparison.They included: DWEL - a dual-wavelength full-waveform laser scanner (Boston U., U. Massachusetts Lowell, U. Massachusetts Boston, USA) SALCA - a dual-wavelength full-waveform laser scanner (U. Salford, UK) CBL - a canopy biomass lidar, a small ultraportable low-cost multiple discrete return scanner (U. Massachusetts Boston, USA) Riegl VZ400 - a survey-grade commercial waveform scanner (Queensland Government and TERN, U. Queensland, Australia) FARO Focus 3D - a lightweight commercial phase-shift ranging laser scanner (U. Southern Queensland) Two plots were scanned at Karawatha Forest Park, a Terrestrial Ecosystem Research Network (TERN) Supersite, and one plot at D'Aguilar National Park. At each 50 x 100 m plot, a center scan point was surrounded by four scan points located 25 m away in a cross pattern allowing for 3-D reconstructions of scan sites in the form of point clouds. At several center points, multiple instrument configurations (i.e. different beam divergence, angular resolution, pulse rate) were acquired to test the impact of instrument specifications on separation of woody and non-woody materials and estimation of vegetation structure parameters. Three-dimensional Photopoint photographic panoramas were also acquired, providing reconstructions of stems in the form of point clouds using photogrammetric correlation methods. Calibrated reflectance targets were also scanned to compare instrument geometric and radiometric performance. Ancillary data included hemispherical photos, TRAC LAI/clumping measurements, spectra of leaves, bark, litter, and other target components. Wet and dry leaf weights determined water content. Planned intercomparison topics and

  20. Highly Accurate Tree Models Derived from Terrestrial Laser Scan Data: A Method Description

    Directory of Open Access Journals (Sweden)

    Jan Hackenberg

    2014-05-01

    Full Text Available This paper presents a method for fitting cylinders into a point cloud, derived from a terrestrial laser-scanned tree. Utilizing high scan quality data as the input, the resulting models describe the branching structure of the tree, capable of detecting branches with a diameter smaller than a centimeter. The cylinders are stored as a hierarchical tree-like data structure encapsulating parent-child neighbor relations and incorporating the tree’s direction of growth. This structure enables the efficient extraction of tree components, such as the stem or a single branch. The method was validated both by applying a comparison of the resulting cylinder models with ground truth data and by an analysis between the input point clouds and the models. Tree models were accomplished representing more than 99% of the input point cloud, with an average distance from the cylinder model to the point cloud within sub-millimeter accuracy. After validation, the method was applied to build two allometric models based on 24 tree point clouds as an example of the application. Computation terminated successfully within less than 30 min. For the model predicting the total above ground volume, the coefficient of determination was 0.965, showing the high potential of terrestrial laser-scanning for forest inventories.

  1. Monostatic coaxial 1.5 μm laser Doppler velocimeter using a scanning Fabry-Perot interferometer

    DEFF Research Database (Denmark)

    Rodrigo, Peter John; Pedersen, Christian

    2013-01-01

    We present a laser Doppler velocimeter (LDV) in monostatic coaxial arrangement consisting of off-the-shelf telecom-grade components: a single frequency laser (wavelength λ = 1.5 μm) and a high-finesse scanning Fabry-Perot interferometer (sFPI). In contrast to previous 1.5 μm LDV systems based...

  2. On the utilization of novel spectral laser scanning for three-dimensional classification of vegetation elements.

    Science.gov (United States)

    Li, Zhan; Schaefer, Michael; Strahler, Alan; Schaaf, Crystal; Jupp, David

    2018-04-06

    The Dual-Wavelength Echidna Lidar (DWEL), a full waveform terrestrial laser scanner (TLS), has been used to scan a variety of forested and agricultural environments. From these scanning campaigns, we summarize the benefits and challenges given by DWEL's novel coaxial dual-wavelength scanning technology, particularly for the three-dimensional (3D) classification of vegetation elements. Simultaneous scanning at both 1064 nm and 1548 nm by DWEL instruments provides a new spectral dimension to TLS data that joins the 3D spatial dimension of lidar as an information source. Our point cloud classification algorithm explores the utilization of both spectral and spatial attributes of individual points from DWEL scans and highlights the strengths and weaknesses of each attribute domain. The spectral and spatial attributes for vegetation element classification each perform better in different parts of vegetation (canopy interior, fine branches, coarse trunks, etc.) and under different vegetation conditions (dead or live, leaf-on or leaf-off, water content, etc.). These environmental characteristics of vegetation, convolved with the lidar instrument specifications and lidar data quality, result in the actual capabilities of spectral and spatial attributes to classify vegetation elements in 3D space. The spectral and spatial information domains thus complement each other in the classification process. The joint use of both not only enhances the classification accuracy but also reduces its variance across the multiple vegetation types we have examined, highlighting the value of the DWEL as a new source of 3D spectral information. Wider deployment of the DWEL instruments is in practice currently held back by challenges in instrument development and the demands of data processing required by coaxial dual- or multi-wavelength scanning. But the simultaneous 3D acquisition of both spectral and spatial features, offered by new multispectral scanning instruments such as the DWEL, opens

  3. Image-based tracking system for vibration measurement of a rotating object using a laser scanning vibrometer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dongkyu, E-mail: akein@gist.ac.kr; Khalil, Hossam; Jo, Youngjoon; Park, Kyihwan, E-mail: khpark@gist.ac.kr [School of Mechatronics, Gwangju Institute of Science and Technology, Buk-gu, Gwangju, South Korea, 500-712 (Korea, Republic of)

    2016-06-28

    An image-based tracking system using laser scanning vibrometer is developed for vibration measurement of a rotating object. The proposed system unlike a conventional one can be used where the position or velocity sensor such as an encoder cannot be attached to an object. An image processing algorithm is introduced to detect a landmark and laser beam based on their colors. Then, through using feedback control system, the laser beam can track a rotating object.

  4. Image-based tracking system for vibration measurement of a rotating object using a laser scanning vibrometer

    International Nuclear Information System (INIS)

    Kim, Dongkyu; Khalil, Hossam; Jo, Youngjoon; Park, Kyihwan

    2016-01-01

    An image-based tracking system using laser scanning vibrometer is developed for vibration measurement of a rotating object. The proposed system unlike a conventional one can be used where the position or velocity sensor such as an encoder cannot be attached to an object. An image processing algorithm is introduced to detect a landmark and laser beam based on their colors. Then, through using feedback control system, the laser beam can track a rotating object.

  5. Efficacy of patterned scan laser in treatment of macular edema and retinal neovascularization

    Directory of Open Access Journals (Sweden)

    Dimple Modi

    2009-08-01

    -term follow-up. PASCAL® photocoagulation can be performed quicker with less discomfort for patients.Keywords: diabetic retinopathy, laser, macular edema, PASCAL, patterned scan laser, photocoagulation, retinal neovascularization

  6. The rf sigmameter: A digital phase-locked technique for accurate long-range laser scanning

    International Nuclear Information System (INIS)

    Zhu, M.; Hall, J.L.

    1986-01-01

    The authors use a new version of a sigmameter, the two-channel field-widened rf sigmameter, to map optical frequency into the phase of an rf signal. This enables them to lock the laser frequency on the interferometer by using a phase-locked loop (PLL). Controlling the reference phase of the PLL electronically, they are able to scan the laser frequency over a long range step by step or with substeps. The systematic error of each substep is cancelled automatically when the authors change one step (which is ten substeps, for example), and that of each step is cancelled when they change the reference phase by 2π (which corresponds to 256 steps in their scheme)

  7. Best ellipse and cylinder parameters estimation from laser profile scan sections

    Science.gov (United States)

    Rahayem, Mohamed; Werghi, Naoufel; Kjellander, Johan

    2012-09-01

    Industrial applications like robot-aided welding, automated inspection, and 3D measurements require 3D points to be captured from the surfaces of objects and processed to calculate the information-of-interest. The lack of research focused on fitting ellipses to 3D laser profile data, and the intrinsic features that distinguish it from 2D digital images, motivated us to conduct a comparative study involving the most popular ellipse-fitting methods. After describing our laser profile scanning system, and a survey of ellipse-fitting methods, we compare, using extensive experiments performed with synthetic and real data, the fitting algorithms in terms of stability and accuracy with respect to a variety of factors. The estimate obtained with the best method is used to initialize a robust non-linear iterative ellipse fitting method. Finally, we describe a novel method for the construction of cylindrical surfaces from estimated elliptical sections.

  8. Application of laser scanning technique in earthquake protection of Istanbul's historical heritage buildings

    Science.gov (United States)

    Çaktı, Eser; Ercan, Tülay; Dar, Emrullah

    2017-04-01

    Istanbul's vast historical and cultural heritage is under constant threat of earthquakes. Historical records report repeated damages to the city's landmark buildings. Our efforts towards earthquake protection of several buildings in Istanbul involve earthquake monitoring via structural health monitoring systems, linear and non-linear structural modelling and analysis in search of past and future earthquake performance, shake-table testing of scaled models and non-destructive testing. More recently we have been using laser technology in monitoring structural deformations and damage in five monumental buildings which are Hagia Sophia Museum and Fatih, Sultanahmet, Süleymaniye and Mihrimah Sultan Mosques. This presentation is about these efforts with special emphasis on the use of laser scanning in monitoring of edifices.

  9. Antibiofilm Activity of Five Different Endodontic Filling Materials Used in Primary Teeth Using Confocal Laser Scanning Microscopy.

    Science.gov (United States)

    Pilownic, Katerine Jahnecke; Carvalho, Ceci Nunes; Romano, Ana Regina; Morgental, Renata Dornelles; Shen, Ya; Haapasalo, Markus; Pappen, Fernanda Geraldo

    2017-03-15

    The purpose of this study was to evaluate the effect of five endodontic materials for primary teeth on in vitro mixed-species biofilms. Zinc oxide eugenol (ZOE) cement, Vitapex, Calen paste thickened with zinc oxide (ZO), pure calcium hydroxide (Ca(OH)2) paste, and iodoform were evaluated. Sterile water was used as a control. Mixed-species biofilm was incubated in anaerobic conditions for 21 days. The biofilm specimens were placed in contact with the endodontic materials for periods of seven and 30 days. The biofilm was studied by using confocal laser scanning microscopy. The cell viability ratio was calculated. The results were analyzed using analysis of variance and Tukey tests. There was a statistically significant difference between groups at both seven and 30 days (F equals 73,073, P=0.00). After 30 days, 69 percent, 51 percent, and 35 percent of the biofilm volume fluoresced red, indicating the proportion of bacteria killed by iodoform, Vitapex, and ZOE cement, respectively. Calen plus ZO and pure Ca(OH)2 paste were the least effective materials against the biofilms. Pure iodoform paste and iodoform containing Vitapex were the most effective materials against the biofilms. Vitapex appears to be a suitable endodontic material for primary teeth.

  10. Confocal laser scanning and electron microscopical studies on osmoregulatory epithelia in the branchial cavity of the lobster homarus gammarus

    Science.gov (United States)

    Haond; Flik; Charmantier

    1998-06-01

    The adult lobster Homarus gammarus is a weak hyper-regulator at low salinity. The objective of this study was to locate the ion-transporting tissues in the branchial chamber of this species, using electron microscopy and confocal laser scanning microscopy with a fluorescent vital stain for mitochondria, DASPMI, which is widely used to locate mitochondria-rich cells in ion-transporting epithelia of fish. A thick mitochondria-rich epithelium is present on the inner side of the branchiostegite and over the entire surface of the epipodites. Ultrastructural observations confirm that this tissue has features typical of an ion-transporting epithelium. When the lobster is transferred to low salinity, these epithelia undergo marked ultrastructural changes, such as an increase in thickness related to the development of basolateral infoldings, the appearance of numerous vesicles and an increase in height of the apical microvilli. In the gills, the branchial filaments are lined by a thin and poorly differentiated epithelium, containing numerous mitochondria; no significant ultrastructural changes were observed in the gills of animals acclimated to low salinity. In summary, in H. gammarus, no evidence of osmoregulatory structures was found in the gills. Differentiated ion-transporting epithelia are present in the branchial cavity, on the inner side of the branchiostegite and on the epipodites; these organs are probably involved in osmoregulation.

  11. Nano-zymography Using Laser-Scanning Confocal Microscopy Unmasks Proteolytic Activity of Cell-Derived Microparticles.

    Science.gov (United States)

    Briens, Aurélien; Gauberti, Maxime; Parcq, Jérôme; Montaner, Joan; Vivien, Denis; Martinez de Lizarrondo, Sara

    2016-01-01

    Cell-derived microparticles (MPs) are nano-sized vesicles released by activated cells in the extracellular milieu. They act as vectors of biological activity by carrying membrane-anchored and cytoplasmic constituents of the parental cells. Although detection and characterization of cell-derived MPs may be of high diagnostic and prognostic values in a number of human diseases, reliable measurement of their size, number and biological activity still remains challenging using currently available methods. In the present study, we developed a protocol to directly image and functionally characterize MPs using high-resolution laser-scanning confocal microscopy. Once trapped on annexin-V coated micro-wells, we developed several assays using fluorescent reporters to measure their size, detect membrane antigens and evaluate proteolytic activity (nano-zymography). In particular, we demonstrated the applicability and specificity of this method to detect antigens and proteolytic activities of tissue-type plasminogen activator (tPA), urokinase and plasmin at the surface of engineered MPs from transfected cell-lines. Furthermore, we were able to identify a subset of tPA-bearing fibrinolytic MPs using plasma samples from a cohort of ischemic stroke patients who received thrombolytic therapy and in an experimental model of thrombin-induced ischemic stroke in mice. Overall, this method is promising for functional characterization of cell-derived MPs.

  12. Molecular characterization and confocal laser scanning microscopic study of Pygidiopsis macrostomum (Trematoda: Heterophyidae) parasites of guppies Poecilia vivipara.

    Science.gov (United States)

    Borges, J N; Costa, V S; Mantovani, C; Barros, E; Santos, E G N; Mafra, C L; Santos, C P

    2017-02-01

    Pygidiopsis macrostomum and Ascocotyle (Phagicola) pindoramensis (Digenea: Heterophyidae) parasitize guppies as intermediate hosts and, respectively, fish-eating mammals or birds as definitive hosts. Heterophyids have zoonotic potential, and molecular studies associated with morphological and ecological aspects have helped to clarify their taxonomy and phylogeny. Poecilia vivipara naturally parasitized by metacercariae of both species (100% prevalence) exhibit no external signs of parasitism. In this work, four new sequences of P. macrostomum (18S rDNA, 28S rDNA and ITS2 rDNA) and one new sequence of A. (P.) pindoramensis (mtDNA cox-1) are presented. Phylogeny reconstructions linked P. macrostomum to other heterophyids, but the separation of the Heterophyidae and Opisthorchiidae remains unclear. Additionally, we used indirect immunocytochemistry and the phalloidin-fluorescence techniques allied with confocal laser scanning microscopy to describe muscular and neuronal structures of P. macrostomum. A complex arrangement of muscular fibres is associated with the tegument, suckers, gut and reproductive system. Radial fibres around the ventral sucker are thick, branched and extend to the body wall. High-resolution confocal imaging revealed a typical digenean muscular arrangement and important heterophyid morphological traits. These data will support future control measures to reduce the parasitism in guppies reared in fish farming systems, especially for aquarium and experimental purposes. © 2016 John Wiley & Sons Ltd.

  13. Methodological considerations of terrestrial laser scanning for vegetation monitoring in the sagebrush steppe

    Science.gov (United States)

    Anderson, Kyle E.; Glenn, Nancy; Spaete, Lucas; Shinneman, Douglas; Pilliod, David S.; Arkle, Robert; McIlroy, Susan; Derryberry, DeWayne R.

    2017-01-01

    Terrestrial laser scanning (TLS) provides fast collection of high-definition structural information, making it a valuable field instrument to many monitoring applications. A weakness of TLS collections, especially in vegetation, is the occurrence of unsampled regions in point clouds where the sensor’s line-of-sight is blocked by intervening material. This problem, referred to as occlusion, may be mitigated by scanning target areas from several positions, increasing the chance that any given area will fall within the scanner’s line-of-sight from at least one position. Because TLS collections are often employed in remote regions where the scope of sampling is limited by logistical factors such as time and battery power, it is important to design field protocols which maximize efficiency and support increased quantity and quality of the data collected. This study informs researchers and practitioners seeking to optimize TLS sampling methods for vegetation monitoring in dryland ecosystems through three analyses. First, we quantify the 2D extent of occluded regions based on the range from single scan positions. Second, we measure the efficacy of additional scan positions on the reduction of 2D occluded regions (area) using progressive configurations of scan positions in 1 ha plots. Third, we test the reproducibility of 3D sampling yielded by a 5-scan/ha sampling methodology using redundant sets of scans. Analyses were performed using measurements at analysis scales of 5 to 50 cm across the 1-ha plots, and we considered plots in grass and shrub-dominated communities separately. In grass-dominated plots, a center-scan configuration and 5 cm pixel size sampled at least 90% of the area up to 18 m away from the scanner. In shrub-dominated plots, sampling at least 90% of the area was only achieved within a distance of 12 m. We found that 3 and 5 scans/ha are needed to sample at least ~ 70% of the total area (1 ha) in the grass and shrub-dominated plots

  14. A NEW APPROACH FOR SUBWAY TUNNEL DEFORMATION MONITORING: HIGH-RESOLUTION TERRESTRIAL LASER SCANNING

    Directory of Open Access Journals (Sweden)

    J. Li

    2012-07-01

    Full Text Available With the improvement of the accuracy and efficiency of laser scanning technology, high-resolution terrestrial laser scanning (TLS technology can obtain high precise points-cloud and density distribution and can be applied to high-precision deformation monitoring of subway tunnels and high-speed railway bridges and other fields. In this paper, a new approach using a points-cloud segmentation method based on vectors of neighbor points and surface fitting method based on moving least squares was proposed and applied to subway tunnel deformation monitoring in Tianjin combined with a new high-resolution terrestrial laser scanner (Riegl VZ-400. There were three main procedures. Firstly, a points-cloud consisted of several scanning was registered by linearized iterative least squares approach to improve the accuracy of registration, and several control points were acquired by total stations (TS and then adjusted. Secondly, the registered points-cloud was resampled and segmented based on vectors of neighbor points to select suitable points. Thirdly, the selected points were used to fit the subway tunnel surface with moving least squares algorithm. Then a series of parallel sections obtained from temporal series of fitting tunnel surfaces were compared to analysis the deformation. Finally, the results of the approach in z direction were compared with the fiber optical displacement sensor approach and the results in x, y directions were compared with TS respectively, and comparison results showed the accuracy errors of x, y, z directions were respectively about 1.5 mm, 2 mm, 1 mm. Therefore the new approach using high-resolution TLS can meet the demand of subway tunnel deformation monitoring.

  15. Street-side vehicle detection, classification and change detection using mobile laser scanning data

    Science.gov (United States)

    Xiao, Wen; Vallet, Bruno; Schindler, Konrad; Paparoditis, Nicolas

    2016-04-01

    Statistics on street-side car parks, e.g. occupancy rates, parked vehicle types, parking durations, are of great importance for urban planning and policy making. Related studies, e.g. vehicle detection and classification, mostly focus on static images or video. Whereas mobile laser scanning (MLS) systems are increasingly utilized for urban street environment perception due to their direct 3D information acquisition, high accuracy and movability. In this paper, we design a complete system for car park monitoring, including vehicle recognition, localization, classification and change detection, from laser scanning point clouds. The experimental data are acquired by an MLS system using high frequency laser scanner which scans the streets vertically along the system's moving trajectory. The point clouds are firstly classified as ground, building façade, and street objects which are then segmented using state-of-the-art methods. Each segment is treated as an object hypothesis, and its geometric features are extracted. Moreover, a deformable vehicle model is fitted to each object. By fitting an explicit model to the vehicle points, detailed information, such as precise position and orientation, can be obtained. The model parameters are also treated as vehicle features. Together with the geometric features, they are applied to a supervised learning procedure for vehicle or non-vehicle recognition. The classes of detected vehicles are also investigated. Whether vehicles have changed across two datasets acquired at different times is detected to estimate the durations. Here, vehicles are trained pair-wisely. Two same or different vehicles are paired up as training samples. As a result, the vehicle recognition, classification and change detection accuracies are 95.9%, 86.0% and 98.7%, respectively. Vehicle modelling improves not only the recognition rate, but also the localization precision compared to bounding boxes.

  16. Fabrication of multifaceted, micropatterned surfaces and image-guided patterning using laser scanning lithography.

    Science.gov (United States)

    Slater, John H; West, Jennifer L

    2014-01-01

    This protocol describes the implementation of laser scanning lithography (LSL) for the fabrication of multifaceted, patterned surfaces and for image-guided patterning. This photothermal-based patterning technique allows for selective removal of desired regions of an alkanethiol self-assembled monolayer on a metal film through raster scanning a focused 532 nm laser using a commercially available laser scanning confocal microscope. Unlike traditional photolithography methods, this technique does not require the use of a physical master and instead utilizes digital "virtual masks" that can be modified "on the fly" allowing for quick pattern modifications. The process to create multifaceted, micropatterned surfaces, surfaces that display pattern arrays of multiple biomolecules with each molecule confined to its own array, is described in detail. The generation of pattern configurations from user-chosen images, image-guided LSL is also described. This protocol outlines LSL in four basic sections. The first section details substrate preparation and includes cleaning of glass coverslips, metal deposition, and alkanethiol functionalization. The second section describes two ways to define pattern configurations, the first through manual input of pattern coordinates and dimensions using Zeiss AIM software and the second via image-guided pattern generation using a custom-written MATLAB script. The third section describes the details of the patterning procedure and postpatterning functionalization with an alkanethiol, protein, and both, and the fourth section covers cell seeding and culture. We end with a general discussion concerning the pitfalls of LSL and present potential improvements that can be made to the technique. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. THE BENEFITS OF TERRESTRIAL LASER SCANNING AND HYPERSPECTRAL DATA FUSION PRODUCTS

    Directory of Open Access Journals (Sweden)

    S. J. Buckley

    2012-10-01

    Full Text Available Close range hyperspectral imaging is a developing method for the analysis and identification of material composition in many applications, such as in within the earth sciences. Using compact imaging devices in the field allows near-vertical topography to be imaged, thus bypassing the key limitations of viewing angle and resolution that preclude the use of airborne and spaceborne platforms. Terrestrial laser scanning allows 3D topography to be captured with high precision and spatial resolution. The combination of 3D geometry from laser scanning, and material properties from hyperspectral imaging allows new fusion products to be created, adding new information for solving application problems. This paper highlights the advantages of terrestrial lidar and hyperspectral integration, focussing on the qualitative and quantitative aspects, with examples from a geological field application. Accurate co-registration of the two data types is required. This allows 2D pixels to be linked to the 3D lidar geometry, giving increased quantitative analysis as classified material vectors are projected to 3D space for calculation of areas and examination of spatial relationships. User interpretation of hyperspectral results in a spatially-meaningful manner is facilitated using visual methods that combine the geometric and mineralogical products in a 3D environment. Point cloud classification and the use of photorealistic modelling enhance qualitative validation and interpretation, and allow image registration accuracy to be checked. A method for texture mapping of lidar meshes with multiple image textures, both conventional digital photos and hyperspectral results, is described. The integration of terrestrial laser scanning and hyperspectral imaging is a valuable means of providing new analysis methods, suitable for many applications requiring linked geometric and chemical information.

  18. Determining the 3-D structure and motion of objects using a scanning laser range sensor

    Science.gov (United States)

    Nandhakumar, N.; Smith, Philip W.

    1993-12-01

    In order for the EVAHR robot to autonomously track and grasp objects, its vision system must be able to determine the 3-D structure and motion of an object from a sequence of sensory images. This task is accomplished by the use of a laser radar range sensor which provides dense range maps of the scene. Unfortunately, the currently available laser radar range cameras use a sequential scanning approach which complicates image analysis. Although many algorithms have been developed for recognizing objects from range images, none are suited for use with single beam, scanning, time-of-flight sensors because all previous algorithms assume instantaneous acquisition of the entire image. This assumption is invalid since the EVAHR robot is equipped with a sequential scanning laser range sensor. If an object is moving while being imaged by the device, the apparent structure of the object can be significantly distorted due to the significant non-zero delay time between sampling each image pixel. If an estimate of the motion of the object can be determined, this distortion can be eliminated; but, this leads to the motion-structure paradox - most existing algorithms for 3-D motion estimation use the structure of objects to parameterize their motions. The goal of this research is to design a rigid-body motion recovery technique which overcomes this limitation. The method being developed is an iterative, linear, feature-based approach which uses the non-zero image acquisition time constraint to accurately recover the motion parameters from the distorted structure of the 3-D range maps. Once the motion parameters are determined, the structural distortion in the range images is corrected.

  19. Photogrammetry and Laser Scanning for the Earth Sciencesworking Group V6

    Science.gov (United States)

    Chandler, J. H.; Buckley, S. J.; Rieke-Zapp, D.; Wackrow, R.

    2012-07-01

    With the UK gaining responsibility for Commission V at the Beijing Congress in 2008, there was an opportunity to create a new working group focusing on earth science applications at close range. The earth science community has had a long tradition of using close range photogrammetry, and more recently laser scanning, and such opportunities have not been fully recognised by ISPRS in the past. Formation of a new ISPRS Working Group helps to bridge this gap and promotes the skills of ISPRS members more widely. The purpose of this paper is to justify the creation of Working Group V6 and identify some of the activities conducted over the last four years. In particular, reference will be made to the various technical sessions which have been organised and supported across the world, the first resulting in a Special Issue of The Photogrammetric Record published in September 2010. In addition, Working Group V6 has been responsible for the creation of two freely available guidance documents entitled "tips for the effective use of digital close range photogrammetry and terrestrial laser scanning". The former focuses on close range digital photogrammetry and has developed through several iterations with input from both academic and industrial users from around the world. For this reason it should be of distinct value to new and perhaps non-expert users interested in using photogrammetry for earth science applications. The paper includes a discussion which considers whether the initial four years of activity have been successful. A superficial assessment based upon the number of members attracted worldwide would suggest that this has indeed been the case. A deeper comparison between proposed activities and those actually achieved suggest some discrepancy, which is perhaps inevitable as Working Group Officers clearly have other responsibilities. However, examination of papers published in the earth surface journals reveal high incidence of photogrammetry and laser scanning

  20. ANALYSIS OF MOBILE LASER SCANNING DATA AND MULTI-VIEW IMAGE RECONSTRUCTION

    Directory of Open Access Journals (Sweden)

    C. Briese

    2012-07-01

    Full Text Available The combination of laser scanning (LS, active, direct 3D measurement of the object surface and photogrammetry (high geometric and radiometric resolution is widely applied for object reconstruction (e.g. architecture, topography, monitoring, archaeology. Usually the results are a coloured point cloud or a textured mesh. The geometry is typically generated from the laser scanning point cloud and the radiometric information is the result of image acquisition. In the last years, next to significant developments in static (terrestrial LS and kinematic LS (airborne and mobile LS hardware and software, research in computer vision and photogrammetry lead to advanced automated procedures in image orientation and image matching. These methods allow a highly automated generation of 3D geometry just based on image data. Founded on advanced feature detector techniques (like SIFT (Scale Invariant Feature Transform very robust techniques for image orientation were established (cf. Bundler. In a subsequent step, dense multi-view stereo reconstruction algorithms allow the generation of very dense 3D point clouds that represent the scene geometry (cf. Patch-based Multi-View Stereo (PMVS2. Within this paper the usage of mobile laser scanning (MLS and simultaneously acquired image data for an advanced integrated scene reconstruction is studied. For the analysis the geometry of a scene is generated by both techniques independently. Then, the paper focuses on the quality assessment of both techniques. This includes a quality analysis of the individual surface models and a comparison of the direct georeferencing of the images using positional and orientation data of the on board GNSS-INS system and the indirect georeferencing of the imagery by automatic image orientation. For the practical evaluation a dataset from an archaeological monument is utilised. Based on the gained knowledge a discussion of the results is provided and a future strategy for the integration of