Fractional ablative erbium YAG laser: histological characterization of relationships between laser settings and micropore dimensions.

Science.gov (United States)

Taudorf, Elisabeth H; Haak, Christina S; Erlendsson, Andrés M; Philipsen, Peter A; Anderson, R Rox; Paasch, Uwe; Haedersdal, Merete

2014-04-01

Treatment of a variety of skin disorders with ablative fractional lasers (AFXL) is driving the development of portable AFXLs. This study measures micropore dimensions produced by a small 2,940 nm AFXL using a variety of stacked pulses, and determines a model correlating laser parameters with tissue effects. Ex vivo pig skin was exposed to a miniaturized 2,940 nm AFXL, spot size 225 µm, density 5%, power levels 1.15-2.22 W, pulse durations 50-225 microseconds, pulse repetition rates 100-500 Hz, and 2, 20, or 50 stacked pulses, resulting in pulse energies of 2.3-12.8 mJ/microbeam and total energy levels of 4.6-640 mJ/microchannel. Histological endpoints were ablation depth (AD), coagulation zone (CZ) and ablation width (AW). Data were logarithmically transformed if required prior to linear regression analyses. Results for histological endpoints were combined in a mathematical model. In 138 sections from 91 biopsies, AD ranged from 16 to a maximum of 1,348 µm and increased linearly with the logarithm of total energy delivered by stacked pulses, but also depended on variations in power, pulse duration, pulse repetition rate, and pulse energy (r(2)  = 0.54-0.85, P micropores of specific ADs with an associated range of CZs and AWs, for example, 300 µm ADs were associated with CZs from 27 to 73 µm and AWs from 190 to 347 µm. Pulse stacking with a small, low power 2,940 nm AFXL created reproducible shallow to deep micropores, and influenced micropore configuration. Mathematical modeling established relations between laser settings and micropore dimensions, which assists in choosing laser settings for desired tissue effects. © 2014 Wiley Periodicals, Inc.

Large Signal Circuit Model of Two-Section Gain Lever Quantum Dot Laser

International Nuclear Information System (INIS)

Horri Ashkan; Mirmoeini Seyedeh Zahra; Faez Rahim

2012-01-01

An equivalent circuit model for the design and analysis of two-section gain lever quantum dot (QD) laser is presented. This model is based on the three level rate equations with two independent carrier populations and a single longitudinal optical mode. By using the presented model, the effect of gain lever on QD laser performances is investigated. The results of simulation show that the main characteristics of laser such as threshold current, transient response, output power and modulation response are affected by differential gain ratios between the two-sections

Application of a plasma-jet for skin antisepsis: analysis of the thermal action of the plasma by laser scanning microscopy

International Nuclear Information System (INIS)

Lademann, O; Kramer, A; Richter, H; Patzelt, A; Alborova, A; Humme, D; Weltmann, K-D; Hartmann, B; Hinz, P; Koch, S

2010-01-01

Recently, it was reported that a plasma-jet could be efficiently applied for the antisepsis of wounds. In this case, the discharge in an argon gas stream was used to produce a so-called ''cold plasma'' on the skin surface. The thermal action of the plasma on the skin was investigated in the present study by means of laser scanning microscopy (LSM) and by histological analysis. Consequently, the plasma beam was moved with a definite velocity at an optimal distance over the skin surface. The structural changes of the tissue were analyzed. It was found by LSM that a thermal damage could be detected only in the upper cell layers of the stratum corneum (SC) at moving velocities of the plasma beam, usually applied in clinical practice. Deeper parts of the SC were not damaged. The structural changes were so superficial that they could be detected only by LSM but not by analysis of the histological sections

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.

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

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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.

Combining confocal laser scanning microscopy with serial section reconstruction in the study of adult neurogenesis.

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Federico eLuzzati

2011-05-01

Full Text Available Current advances in imaging techniques have extended the possibility of visualizing small structures within large volumes of both fixed and live specimens without sectioning. These techniques have contributed valuable information to study neuronal plasticity in the adult brain. However, technical limits still hamper the use of these approaches to investigate neurogenic regions located far from the ventricular surface such as parenchymal neurogenic niches, or the scattered neuroblasts induced by brain lesions. Here, we present a method to combine confocal laser scanning microscopy (CLSM and serial section reconstruction in order to reconstruct large volumes of brain tissue at cellular resolution. In this method a series of thick sections are imaged with CLSM and the resulting stacks of images are registered and 3D reconstructed. This approach is based on existing freeware software and can be performed on ordinary laboratory personal computers (PC. By using this technique we have investigated the morphology and spatial organization of a group of doublecortin (DCX+ neuroblasts located in the lateral striatum of the late post-natal guinea pig. The 3D study unravelled a complex network of long and poorly ramified cell processes, often fascicled and mostly oriented along the internal capsule fibre bundles. These data support CLSM serial section reconstruction as a reliable alternative to the whole mount approaches to analyze cyto-architectural features of adult germinative niches.

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).

Long-term efficacy of linear-scanning 808 nm diode laser for hair removal compared to a scanned alexandrite laser.

Science.gov (United States)

Grunewald, Sonja; Bodendorf, Marc Oliver; Zygouris, Alexander; Simon, Jan Christoph; Paasch, Uwe

2014-01-01

Alexandrite and diode lasers are commonly used for hair removal. To date, the available spot sizes and repetition rates are defining factors in terms of penetration depth, treatment speed, and efficacy. Still, larger treatment areas and faster systems are desirable. To compare the efficacy, tolerability, and subject satisfaction of a continuously linear-scanning 808 nm diode laser with an alexandrite 755 nm laser for axillary hair removal. A total of 31 adults with skin types I-IV received 6 treatments at 4-week intervals with a 755 nm alexandrite laser (right axilla) and a continuously linear-scanning 808 nm diode laser (left axilla). Axillary hair density was assessed using a computerized hair detection system. There was a significant reduction in axillary hair after the 6th treatment (P lasers was not significant, but both were persistant at 18 months follow-up (left: hair clearance of 73.71%; right: hair clearance of 71.90%). Erythema and perifollicular edema were more common after alexandrite laser treatment, but all side effects were transient. While 62.50% of patients reported more pain in response to treatment with the new diode laser, all patients rated treatment with either laser tolerable. Treatment with either the alexandrite or the linear-scanning diode laser results in significant, comparable, persistent (at least 18 months) axillary hair reduction among individuals with skin types I-IV. © 2013 Wiley Periodicals, Inc.

Gambaran CT Scan Toraks Sesuai dengan Jenis Sitologi/Histologi pada Pasien Kanker Paru yang Merokok

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Rosa Tatun

2016-03-01

Full Text Available Kanker paru merupakan  penyebab kematian paling banyak akibat keganasan. Kanker paru memberikan gambaran CT scan yang berbeda sesuai dengan jenis sitologi/histologinya. Pemeriksaan CT scan  toraksdengan teknik high resolution computed tomography (HRCT dapat memperlihatkan kelainan kanker parusecara rinci. Penelitian dilakukan di Instalasi Radiologi RSU Persahabatan, Jakarta bekerja sama denganDepartemen Pulmonologi dan Respirasi RSU Persahabatan terhadap 100 sampel yang diperoleh pada bulanNovember 2014 hingga Maret 2015. Berdasarkan jenis sitologi/histologi kanker paru (adenokarsinoma dankarsinoma sel skuamosa/KSS tidak ditemukan  variabel yang bermakna secara statistik  (bentuk, letak, tepispikulasi, tepi lobulasi, nodul satelit. Variabel yang paling banyak ditemukan pada adenokarsinoma maupunKSS adalah bentuk massa, lokasi di sentral dan paru sebelah kanan. Gambaran kanker paru adenokarsinomadan KSS pada pasien merokok paling banyak berupa massa, lokasi di sentral dan lobus kanan paru. Kata kunci: kanker paru, merokok, CT scan toraks   Lung Cancer CT Scan Findings in Smoker Patients Basedon Cytology/Histology Abstract Lung cancer is the leading cause of most deaths due to malignancy. Lung cancer CT scan provides an overview according to the type of cytology / histology. Thorax CT scan with high resolution technique (HRCT may revealdetail lung cancer abnormalities. This study was conducted between Department of Radiology and Departmentof Pulmonology Respiratory, Persahabatan Hospital Jakarta based on 100 samples, November 2014 until March2015. Based on cytological/histological type (adenocarcinoma and squamous cell carcinoma/KSS, it was not found significant meaningfull variables (shape, location, spiculate edge, lobulate edge, satellite nodules. Most commonly variables found in adenocarcinomas and KSS were mass forming, central location, right lung location.Most of adenocarcinoma and SCC in smoked patients were mass forming, central

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.

Utilizing 3D Printing Technology to Merge MRI with Histology: A Protocol for Brain Sectioning

Science.gov (United States)

Luciano, Nicholas J; Sati, Pascal; Nair, Govind; Guy, Joseph R; Ha, Seung-Kwon; Absinta, Martina; Chiang, Wen-Yang; Leibovitch, Emily C; Jacobson, Steven; Silva, Afonso C; Reich, Daniel S.

2016-01-01

Magnetic resonance imaging (MRI) allows for the delineation between normal and abnormal tissue on a macroscopic scale, sampling an entire tissue volume three-dimensionally. While MRI is an extremely sensitive tool for detecting tissue abnormalities, association of signal changes with an underlying pathological process is usually not straightforward. In the central nervous system, for example, inflammation, demyelination, axonal damage, gliosis, and neuronal death may all induce similar findings on MRI. As such, interpretation of MRI scans depends on the context, and radiological-histopathological correlation is therefore of the utmost importance. Unfortunately, traditional pathological sectioning of brain tissue is often imprecise and inconsistent, thus complicating the comparison between histology sections and MRI. This article presents novel methodology for accurately sectioning primate brain tissues and thus allowing precise matching between histology and MRI. The detailed protocol described in this article will assist investigators in applying this method, which relies on the creation of 3D printed brain slicers. Slightly modified, it can be easily implemented for brains of other species, including humans. PMID:28060281

Utilizing 3D Printing Technology to Merge MRI with Histology: A Protocol for Brain Sectioning.

Science.gov (United States)

Luciano, Nicholas J; Sati, Pascal; Nair, Govind; Guy, Joseph R; Ha, Seung-Kwon; Absinta, Martina; Chiang, Wen-Yang; Leibovitch, Emily C; Jacobson, Steven; Silva, Afonso C; Reich, Daniel S

2016-12-06

Magnetic resonance imaging (MRI) allows for the delineation between normal and abnormal tissue on a macroscopic scale, sampling an entire tissue volume three-dimensionally. While MRI is an extremely sensitive tool for detecting tissue abnormalities, association of signal changes with an underlying pathological process is usually not straightforward. In the central nervous system, for example, inflammation, demyelination, axonal damage, gliosis, and neuronal death may all induce similar findings on MRI. As such, interpretation of MRI scans depends on the context, and radiological-histopathological correlation is therefore of the utmost importance. Unfortunately, traditional pathological sectioning of brain tissue is often imprecise and inconsistent, thus complicating the comparison between histology sections and MRI. This article presents novel methodology for accurately sectioning primate brain tissues and thus allowing precise matching between histology and MRI. The detailed protocol described in this article will assist investigators in applying this method, which relies on the creation of 3D printed brain slicers. Slightly modified, it can be easily implemented for brains of other species, including humans.

Structural monitoring of tunnels using terrestrial laser scanning

NARCIS (Netherlands)

Lindenbergh, R.C.; Uchanski, L.; Bucksch, A.; Van Gosliga, R.

2009-01-01

In recent years terrestrial laser scanning is rapidly evolving as a surveying technique for the monitoring of engineering objects like roof constructions, mines, dams, viaducts and tunnels. The advantage of laser scanning above traditional surveying methods is that it allows for the rapid

Early human bone response to laser metal sintering surface topography: a histologic report.

Science.gov (United States)

Mangano, Carlo; Piattelli, Adriano; d'Avila, Susana; Iezzi, Giovanna; Mangano, Francesco; Onuma, Tatiana; Shibli, Jamil Awad

2010-01-01

This histologic report evaluated the early human bone response to a direct laser metal sintering implant surface retrieved after a short period of healing. A selective laser sintering procedure using a Ti-6Al-4V alloy powder with a particle size of 25-45 microm prepared this surface topography. One experimental microimplant was inserted into the anterior mandible of a patient during conventional implant surgery of the jaw. The microimplant and surrounding tissues were removed after 2 months of unloaded healing and were prepared for histomorphometric analysis. Histologically, the peri-implant bone appeared in close contact with the implant surface, whereas marrow spaces could be detected in other areas along with prominently stained cement lines. The mean of bone-to-implant contact was 69.51%. The results of this histologic report suggest that the laser metal sintering surface could be a promising alternative to conventional implant surface topographies.

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

A New Multichannel Spectral Imaging Laser Scanning Confocal Microscope

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Yunhai Zhang

2013-01-01

Full Text Available We have developed a new multichannel spectral imaging laser scanning confocal microscope for effective detection of multiple fluorescent labeling in the research of biological tissues. In this paper, the design and key technologies of the system are introduced. Representative results on confocal imaging, 3-dimensional sectioning imaging, and spectral imaging are demonstrated. The results indicated that the system is applicable to multiple fluorescent labeling in biological experiments.

Forest Inventory with Terrestrial LiDAR: A Comparison of Static and Hand-Held Mobile Laser Scanning

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Sébastien Bauwens

2016-06-01

Full Text Available The application of static terrestrial laser scanning (TLS in forest inventories is becoming more effective. Nevertheless, the occlusion effect is still limiting the processing efficiency to extract forest attributes. The use of a mobile laser scanner (MLS would reduce this occlusion. In this study, we assessed and compared a hand-held mobile laser scanner (HMLS with two TLS approaches (single scan: SS, and multi scan: MS for the estimation of several forest parameters in a wide range of forest types and structures. We found that SS is competitive to extract the ground surface of forest plots, while MS gives the best result to describe the upper part of the canopy. The whole cross-section at 1.3 m height is scanned for 91% of the trees (DBH > 10 cm with the HMLS leading to the best results for DBH estimates (bias of −0.08 cm and RMSE of 1.11 cm, compared to no fully-scanned trees for SS and 42% fully-scanned trees for MS. Irregularities, such as bark roughness and non-circular cross-section may explain the negative bias encountered for all of the scanning approaches. The success of using MLS in forests will allow for 3D structure acquisition on a larger scale and in a time-efficient manner.

HistoStitcher© : An Interactive Program for Accurate and Rapid Reconstruction of Digitized Whole Histological Sections from Tissue Fragments

Science.gov (United States)

Chappelow, Jonathan; Tomaszewski, John E.; Feldman, Michael; Shih, Natalie; Madabhushi, Anant

2011-01-01

We present an interactive program called HistoStitcher© for accurate and rapid reassembly of histology fragments into a pseudo-whole digitized histological section. HistoStitcher© provides both an intuitive graphical interface to assist the operator in performing the stitch of adjacent histology fragments by selecting pairs of anatomical landmarks, and a set of computational routines for determining and applying an optimal linear transformation to generate the stitched image. Reconstruction of whole histological sections from images of slides containing smaller fragments is required in applications where preparation of whole sections of large tissue specimens is not feasible or efficient, and such whole mounts are required to facilitate (a) disease annotation and (b) image registration with radiological images. Unlike manual reassembly of image fragments in a general purpose image editing program (such as Photoshop), HistoStitcher© provides memory efficient operation on high resolution digitized histology images and a highly flexible stitching process capable of producing more accurate results in less time. Further, by parameterizing the series of transformations determined by the stitching process, the stitching parameters can be saved, loaded at a later time, refined, or reapplied to multi-resolution scans, or quickly transmitted to another site. In this paper, we describe in detail the design of HistoStitcher© and the mathematical routines used for calculating the optimal image transformation, and demonstrate its operation for stitching high resolution histology quadrants of a prostate specimen to form a digitally reassembled whole histology section, for 8 different patient studies. To evaluate stitching quality, a 6 point scoring scheme, which assesses the alignment and continuity of anatomical structures important for disease annotation, is employed by three independent expert pathologists. For 6 studies compared with this scheme, reconstructed sections

Development of Large Concrete Object Geometrical Model Based on Terrestrial Laser Scanning

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Zaczek-Peplinska Janina

2015-02-01

Full Text Available The paper presents control periodic measurements of movements and survey of concrete dam on Dunajec River in Rożnów, Poland. Topographical survey was conducted using laser scanning technique. The goal of survey was data collection and creation of a geometrical model. Acquired cross- and horizontal sections were utilised to create a numerical model of object behaviour at various load depending of changing level of water in reservoir. Modelling was accomplished using finite elements technique. During the project an assessment was conducted to terrestrial laser scanning techniques for such type of research of large hydrotechnical objects such as gravitational water dams. Developed model can be used to define deformations and displacement prognosis.

Histological evaluation of vertical laser channels from ablative fractional resurfacing: an ex vivo pig skin model.

Science.gov (United States)

Skovbølling Haak, Christina; Illes, Monica; Paasch, Uwe; Hædersdal, Merete

2011-07-01

Ablative fractional resurfacing (AFR) represents a new treatment potential for various skin conditions and new laser devices are being introduced. It is important to gain information about the impact of laser settings on the dimensions of the created laser channels for obtaining a safe and efficient treatment outcome. The aim of this study was to establish a standard model to document the histological tissue damage profiles after AFR and to test a new laser device at diverse settings. Ex vivo abdominal pig skin was treated with a MedArt 620, prototype fractional carbon dioxide (CO(2)) laser (Medart, Hvidovre, Denmark) delivering single microbeams (MB) with a spot size of 165 μm. By using a constant pulse duration of 2 ms, intensities of 1-18 W, single and 2-4 stacked pulses, energies were delivered in a range from 2-144 mJ/MB. Histological evaluations included 3-4 high-quality histological measurements for each laser setting (n = 28). AFR created cone-shaped laser channels. Ablation depths varied from reaching the superficial dermis (2 mJ, median 41 μm) to approaching the subcutaneous fat (144 mJ, median 1,943 μm) and correlated to the applied energy levels in an approximate linear relation (r(2) = 0.84, p skin model to characterize AFR laser channels histologically.

Scanning laser microscope for imaging nanostructured superconductors

International Nuclear Information System (INIS)

Ishida, Takekazu; Arai, Kohei; Akita, Yukio; Miyanari, Mitsunori; Minami, Yusuke; Yotsuya, Tsutomu; Kato, Masaru; Satoh, Kazuo; Uno, Mayumi; Shimakage, Hisashi; Miki, Shigehito; Wang, Zhen

2010-01-01

The nanofabrication of superconductors yields various interesting features in superconducting properties. A variety of different imaging techniques have been developed for probing the local superconducting profiles. A scanning pulsed laser microscope has been developed by the combination of the XYZ piezo-driven stages and an optical fiber with an aspheric focusing lens. The scanning laser microscope is used to understand the position-dependent properties of a superconducting MgB 2 stripline of length 100 μm and width of 3 μm under constant bias current. Our results show that the superconducting stripline can clearly be seen in the contour image of the scanning laser microscope on the signal voltage. It is suggested from the observed image that the inhomogeneity is relevant in specifying the operating conditions such as detection efficiency of the sensor.

Scanning laser microscope for imaging nanostructured superconductors

Science.gov (United States)

Ishida, Takekazu; Arai, Kohei; Akita, Yukio; Miyanari, Mitsunori; Minami, Yusuke; Yotsuya, Tsutomu; Kato, Masaru; Satoh, Kazuo; Uno, Mayumi; Shimakage, Hisashi; Miki, Shigehito; Wang, Zhen

2010-10-01

The nanofabrication of superconductors yields various interesting features in superconducting properties. A variety of different imaging techniques have been developed for probing the local superconducting profiles. A scanning pulsed laser microscope has been developed by the combination of the XYZ piezo-driven stages and an optical fiber with an aspheric focusing lens. The scanning laser microscope is used to understand the position-dependent properties of a superconducting MgB 2 stripline of length 100 μm and width of 3 μm under constant bias current. Our results show that the superconducting stripline can clearly be seen in the contour image of the scanning laser microscope on the signal voltage. It is suggested from the observed image that the inhomogeneity is relevant in specifying the operating conditions such as detection efficiency of the sensor.

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

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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.

Histologic comparison of the pulsed dye laser and copper vapor laser effects on pig skin

Energy Technology Data Exchange (ETDEWEB)

Tan, O.T.; Stafford, T.J.; Murray, S.; Kurban, A.K. (Boston Univ. Medical Center, MA (USA))

1990-01-01

Albino pig skin was exposed to the copper vapor (CVL) and flash-lamp pulsed dye (PDL) lasers at 578 nm with a 3 mm diameter spotsize over a range of fluences until purpura and whitening were first established. The total irradiation time was the parameter that was varied in order for the CVL to reach the desired fluence. The lowest fluence producing each clinical endpoint was designated the threshold fluence: 34 J/cm{sup 2} was required to produce purpura using the CVL compared to 7.5 J/cm{sup 2} with the PDL laser. Histologically, skin exposed to purpura fluences from the CVL revealed the presence of constricted, disrupted papillary dermal blood vessels with trapped RBC's within them which were unlike those exposed to PDL where the irradiated vessels were dilated and packed with masses of intravascular agglutinated RBC's. The whitening threshold fluences for the CVL and PDL lasers were 67 J/cm{sup 2} and 29 J/cm{sup 2}, respectively. Streaming of epidermal cells and dermal collagen denaturation were observed in CVL irradiated skin, compared to occasional dyskeratotic epidermal cells and focal dermal collagen denaturation following PDL exposure. The mechanisms responsible for the clinical and histologic changes produced by the two laser systems are discussed.

BENCHMARKING MOBILE LASER SCANNING SYSTEMS USING A PERMANENT TEST FIELD

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H. Kaartinen

2012-07-01

Full Text Available The objective of the study was to benchmark the geometric accuracy of mobile laser scanning (MLS systems using a permanent test field under good coverage of GNSS. Mobile laser scanning, also called mobile terrestrial laser scanning, is currently a rapidly developing area in laser scanning where laser scanners, GNSS and IMU are mounted onboard a moving vehicle. MLS can be considered to fill the gap between airborne and terrestrial laser scanning. Data provided by MLS systems can be characterized with the following technical parameters: a point density in the range of 100-1000 points per m2 at 10 m distance, b distance measurement accuracy of 2-5 cm, and c operational scanning range from 1 to 100 m. Several commercial, including e.g. Riegl, Optech and others, and some research mobile laser scanning systems surveyed the test field using predefined driving speed and directions. The acquired georeferenced point clouds were delivered for analyzing. The geometric accuracy of the point clouds was determined using the reference targets that could be identified and measured from the point cloud. Results show that in good GNSS conditions most systems can reach an accuracy of 2 cm both in plane and elevation. The accuracy of a low cost system, the price of which is less than tenth of the other systems, seems to be within a few centimetres at least in ground elevation determination. Inaccuracies in the relative orientation of the instruments lead to systematic errors and when several scanners are used, in multiple reproductions of the objects. Mobile laser scanning systems can collect high density point cloud data with high accuracy. A permanent test field suits well for verifying and comparing the performance of different mobile laser scanning systems. The accuracy of the relative orientation between the mapping instruments needs more attention. For example, if the object is seen double in the point cloud due to imperfect boresight calibration between two

Scanning laser optical tomography for in toto imaging of the murine cochlea.

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Lena Nolte

Full Text Available The mammalian cochlea is a complex macroscopic structure due to its helical shape and the microscopic arrangements of the individual layers of cells. To improve the outcomes of hearing restoration in deaf patients, it is important to understand the anatomic structure and composition of the cochlea ex vivo. Hitherto, only one histological technique based on confocal laser scanning microscopy and optical clearing has been developed for in toto optical imaging of the murine cochlea. However, with a growing size of the specimen, e.g., human cochlea, this technique reaches its limitations. Here, we demonstrate scanning laser optical tomography (SLOT as a valuable imaging technique to visualize the murine cochlea in toto without any physical slicing. This technique can also be applied in larger specimens up to cm3 such as the human cochlea. Furthermore, immunolabeling allows visualization of inner hair cells (otoferlin or spiral ganglion cells (neurofilament within the whole cochlea. After image reconstruction, the 3D dataset was used for digital segmentation of the labeled region. As a result, quantitative analysis of position, length and curvature of the labeled region was possible. This is of high interest in order to understand the interaction of cochlear implants (CI and cells in more detail.

Stereological measures of trabecular bone structure: comparison of 3D micro computed tomography with 2D histological sections in human proximal tibial bone biopsies

DEFF Research Database (Denmark)

Thomsen, Jesper Skovhus; Laib, A.; Koller, B.

2005-01-01

Stereology applied on histological sections is the 'gold standard' for obtaining quantitative information on cancellous bone structure. Recent advances in micro computed tomography (microCT) have made it possible to acquire three-dimensional (3D) data non-destructively. However, before the 3D...... methods can be used as a substitute for the current 'gold standard' they have to be verified against the existing standard. The aim of this study was to compare bone structural measures obtained from 3D microCT data sets with those obtained by stereology performed on conventional histological sections...... tibial metaphysis. The biopsies were embedded in methylmetacrylate before microCT scanning in a Scanco microCT 40 scanner at a resolution of 20 x 20 x 20 microm3, and the 3D data sets were analysed with a computer program. After microCT scanning, 16 sections were cut from the central 2 mm of each biopsy...

Electro-optical equivalent calibration technology for high-energy laser energy meters

Energy Technology Data Exchange (ETDEWEB)

Wei, Ji Feng, E-mail: wjfcom2000@163.com [State Key Laboratory of Precision Measurement Technology and Instrument, Tsinghua University, Beijing 100084 (China); Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900 (China); Graduate School of China Academy of Engineering Physics, Beijing 100088 (China); Key Laboratory of Laser Science and Technology, China Academy of Engineering Physics, Mianyang 621900 (China); Chang, Yan; Zhang, Kai; Hu, Xiao Yang; Zhang, Wei [Institute of Applied Electronics, China Academy of Engineering Physics, Mianyang 621900 (China); Key Laboratory of Laser Science and Technology, China Academy of Engineering Physics, Mianyang 621900 (China); Sun, Li Qun [State Key Laboratory of Precision Measurement Technology and Instrument, Tsinghua University, Beijing 100084 (China)

2016-04-15

Electro-optical equivalent calibration with high calibration power and high equivalence is particularly well-suited to the calibration of high-energy laser energy meters. A large amount of energy is reserved during this process, however, which continues to radiate after power-off. This study measured the radiation efficiency of a halogen tungsten lamp during power-on and after power-off in order to calculate the total energy irradiated by a lamp until the high-energy laser energy meter reaches thermal equilibrium. A calibration system was designed based on the measurement results, and the calibration equivalence of the system was analyzed in detail. Results show that measurement precision is significantly affected by the absorption factor of the absorption chamber and by heat loss in the energy meter. Calibration precision is successfully improved by enhancing the equivalent power and reducing power-on time. The electro-optical equivalent calibration system, measurement uncertainty of which was evaluated as 2.4% (k = 2), was used to calibrate a graphite-cone-absorption-cavity absolute energy meter, yielding a calibration coefficient of 1.009 and measurement uncertainty of 3.5% (k = 2). A water-absorption-type high-energy laser energy meter with measurement uncertainty of 4.8% (k = 2) was considered the reference standard, and compared to the energy meter calibrated in this study, yielded a correction factor of 0.995 (standard deviation of 1.4%).

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.

Human Chorioretinal Layer Thicknesses Measured in Macula-wide, High-Resolution Histologic Sections

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Messinger, Jeffrey D.; Sloan, Kenneth R.; Mitra, Arnab; McGwin, Gerald; Spaide, Richard F.

2011-01-01

Purpose. To provide a comprehensive description of chorioretinal layer thicknesses in the normal human macula, including two-layer pairs that can produce a combined signal in some optical coherence tomography (OCT) devices (ganglion cell [GCL] and inner plexiform [IPL] layers and outer plexiform [OPL] and outer nuclear [ONL] layers). Methods. In 0.8-μm-thick, macula-wide sections through the foveola of 18 donors (age range, 40–92 years), 21 layers were measured at 25 locations by a trained observer and validated by a second observer. Tissue volume changes were assessed by comparing total retinal thickness in ex vivo OCT and in sections. Results. Median tissue shrinkage was 14.5% overall and 29% in the fovea. Histologic laminar boundaries resembled those in SD-OCT scans, but the shapes of the foveolar OPL and ONL differed. Histologic GCL, IPL, and OPLHenle were thickest at 0.8. to 1, 1.5, and 0.4 mm eccentricity, respectively. ONL was thickest in an inward bulge at the foveal center. At 1 mm eccentricity, GCL, INL, and OPLHenle represented 17.3% to 21.1%, 18.0% to 18.5%, and 14.2% to 16.6% of total retinal thickness, respectively. In donors ≥70 years of age, the RPE and choroid were 17.1% and 29.6% thinner and OPLHenle was 20.8% thicker than in donors macula were generated. Newer OCT systems can separate GCL from IPL and OPLHenle from ONL, with good agreement for the proportion of retinal thickness occupied by OPLHenle in OCT and histology. The thickening of OPLHenle in older eyes may reflect Müller cell hypertrophy associated with rod loss. PMID:21421869

HOVE-Wedge-Filtering of Geomorphologic Terrestrial Laser Scan Data

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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.

3D prostate histology image reconstruction: Quantifying the impact of tissue deformation and histology section location

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Eli Gibson

2013-01-01

Full Text Available Background: Guidelines for localizing prostate cancer on imaging are ideally informed by registered post-prostatectomy histology. 3D histology reconstruction methods can support this by reintroducing 3D spatial information lost during histology processing. The need to register small, high-grade foci drives a need for high accuracy. Accurate 3D reconstruction method design is impacted by the answers to the following central questions of this work. (1 How does prostate tissue deform during histology processing? (2 What spatial misalignment of the tissue sections is induced by microtome cutting? (3 How does the choice of reconstruction model affect histology reconstruction accuracy? Materials and Methods: Histology, paraffin block face and magnetic resonance images were acquired for 18 whole mid-gland tissue slices from six prostates. 7-15 homologous landmarks were identified on each image. Tissue deformation due to histology processing was characterized using the target registration error (TRE after landmark-based registration under four deformation models (rigid, similarity, affine and thin-plate-spline [TPS]. The misalignment of histology sections from the front faces of tissue slices was quantified using manually identified landmarks. The impact of reconstruction models on the TRE after landmark-based reconstruction was measured under eight reconstruction models comprising one of four deformation models with and without constraining histology images to the tissue slice front faces. Results: Isotropic scaling improved the mean TRE by 0.8-1.0 mm (all results reported as 95% confidence intervals, while skew or TPS deformation improved the mean TRE by <0.1 mm. The mean misalignment was 1.1-1.9΀ (angle and 0.9-1.3 mm (depth. Using isotropic scaling, the front face constraint raised the mean TRE by 0.6-0.8 mm. Conclusions: For sub-millimeter accuracy, 3D reconstruction models should not constrain histology images to the tissue slice front faces and

Histological evaluation of thyroid lesions using a scanning acoustic microscope

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Miura K

2014-02-01

Full Text Available Katsutoshi Miura,1 Hiroyuki Mineta2 1Department of Health Science, Pathology, and Anatomy, 2Department of Otorhinolaryngology, Hamamatsu University School of Medicine, Hamamatsu, Japan Purpose: A scanning acoustic microscope (SAM uses an ultrasound to image an object by plotting the speed-of-sound (SOS through tissues on screen. Because hard tissues result in great SOS, SAM can provide data on the tissue elasticity. This paper investigated the utility of SAM in evaluating thyroid lesions. Methods: Formalin-fixed, paraffin sections were scanned with a 120 MHz transducer. SOS through each area was calculated and plotted on the screen to provide histological images, and SOS of each lesion was compared and statistically analyzed. Results: High-concentrated colloids, red blood cells, and collagen fibers showed great SOS, while low-concentrated colloids, parathyroids, lymph follicles, and epithelial tissues including carcinomas demonstrated lower SOS. SAM clearly discriminated structure of thyroid components corresponding to low magnification of light microscopy. Thyroid tumors were classified into three groups by average SOS: the fast group consisted of follicular adenomas/carcinomas and malignant lymphomas; the slow group contained poorly differentiated/undifferentiated carcinomas; and the intermediate group comprised papillary/medullary carcinomas. Fragmented colloids, irregular-shaped follicles, and desmoplastic reactions were observed in the invasive area of surrounding carcinomas. Conclusion: The SAM imaging method had the following benefits: 1 precise images were acquired in a few minutes without special staining; 2 structural irregularity and desmoplastic reactions, which indicated malignancy, were detected; 3 images reflected tissue elasticity, which was statistically comparable among lesions by SOS; 4 follicular functional activity was predictable by converting colloid concentration to SOS; and 5 tumor classification was predictable by SOS

Three-Dimensional Laser Scanning for Geometry Documentation and Construction Management of Highway Tunnels during Excavation

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Gikas, Vassilis

2012-01-01

Driven by progress in sensor technology, computer software and data processing capabilities, terrestrial laser scanning has recently proved a revolutionary technique for high accuracy, 3D mapping and documentation of physical scenarios and man-made structures. Particularly, this is of great importance in the underground space and tunnel construction environment as surveying engineering operations have a great impact on both technical and economic aspects of a project. This paper discusses the use and explores the potential of laser scanning technology to accurately track excavation and construction activities of highway tunnels. It provides a detailed overview of the static laser scanning method, its principles of operation and applications for tunnel construction operations. Also, it discusses the planning, execution, data processing and analysis phases of laser scanning activities, with emphasis given on geo-referencing, mesh model generation and cross-section extraction. Specific case studies are considered based on two construction sites in Greece. Particularly, the potential of the method is examined for checking the tunnel profile, producing volume computations and validating the smoothness/thickness of shotcrete layers at an excavation stage and during the completion of excavation support and primary lining. An additional example of the use of the method in the geometric documentation of the concrete lining formwork is examined and comparisons against dimensional tolerances are examined. Experimental comparisons and analyses of the laser scanning method against conventional surveying techniques are also considered. PMID:23112655

Multicolor pattern scan laser for diabetic retinopathy with cataract

Institute of Scientific and Technical Information of China (English)

Takao; Hirano; Yasuhiro; Iesato; Toshinori; Murata

2014-01-01

· AIM: To evaluate the ability of various laser wavelengths in delivering sufficient burns to the retina in eyes with cataract using a new multicolor pattern scan laser with green(532 nm), yellow(577 nm), and red(647 nm)lasers.·METHODS: The relationship between the Emery-Little(EL) degree of cataract severity and the laser wavelength required to deliver adequate burns was investigated in102 diabetic eyes. Treatment time, total number of laser shots, and intra-operative pain were assessed as well.·RESULTS: All EL-1 grade eyes and 50% of EL-2 eyes were successfully treated with the green laser, while 50%of EL-2 eyes, 96% of EL-3 eyes, and 50% of EL-4 eyes required the yellow laser. The red laser was effective in the remaining 4% of EL-3 and 50% of EL-4 eyes.·CONCLUSION: Longer wavelength lasers are more effective in delivering laser burns through cataract when we use a multicolor pattern scan laser system.

Multiplatform Mobile Laser Scanning: Usability and Performance

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Yuwei Chen

2012-08-01

Full Text Available Mobile laser scanning is an emerging technology capable of capturing three-dimensional data from surrounding objects. With state-of-the-art sensors, the achieved point clouds capture object details with good accuracy and precision. Many of the applications involve civil engineering in urban areas, as well as traffic and other urban planning, all of which serve to make 3D city modeling probably the fastest growing market segment in this field. This article outlines multiplatform mobile laser scanning solutions such as vehicle- and trolley-operated urban area data acquisition, and boat-mounted equipment for fluvial environments. Moreover, we introduce a novel backpack version of mobile laser scanning equipment for surveying applications in the field of natural sciences where the requirements include precision and mobility in variable terrain conditions. In addition to presenting a technical description of the systems, we discuss the performance of the solutions in the light of various applications in the fields of urban mapping and modeling, fluvial geomorphology, snow-cover characterization, precision agriculture, and in monitoring the effects of climate change on permafrost landforms. The data performance of the mobile laser scanning approach is described by the results of an evaluation of the ROAMER on a permanent MLS test field. Furthermore, an in situ accuracy assessment using a field of spherical 3D targets for the newly-introduced Akhka backpack system is conducted and reported on.

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

Laser cutting of irregular shape object based on stereo vision laser galvanometric scanning system

Science.gov (United States)

Qi, Li; Zhang, Yixin; Wang, Shun; Tang, Zhiqiang; Yang, Huan; Zhang, Xuping

2015-05-01

Irregular shape objects with different 3-dimensional (3D) appearances are difficult to be shaped into customized uniform pattern by current laser machining approaches. A laser galvanometric scanning system (LGS) could be a potential candidate since it can easily achieve path-adjustable laser shaping. However, without knowing the actual 3D topography of the object, the processing result may still suffer from 3D shape distortion. It is desirable to have a versatile auxiliary tool that is capable of generating 3D-adjusted laser processing path by measuring the 3D geometry of those irregular shape objects. This paper proposed the stereo vision laser galvanometric scanning system (SLGS), which takes the advantages of both the stereo vision solution and conventional LGS system. The 3D geometry of the object obtained by the stereo cameras is used to guide the scanning galvanometers for 3D-shape-adjusted laser processing. In order to achieve precise visual-servoed laser fabrication, these two independent components are integrated through a system calibration method using plastic thin film target. The flexibility of SLGS has been experimentally demonstrated by cutting duck feathers for badminton shuttle manufacture.

Biopsy of Different Oral Soft Tissues Lesions by KTP and Diode Laser: Histological Evaluation

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Umberto Romeo

2014-01-01

Full Text Available Introduction. Oral biopsy aims to obtain clear and safe diagnosis; it can be performed by scalpel or laser. The controversy in this latter application is the thermal alteration due to tissue heating. The aim of this study is the histological evaluation of margins of “in vivo” biopsies collected by diode and KTP lasers. Material and Methods. 17 oral benign lesions biopsies were made by diode 808 nm (SOL, DenMatItalia, Italy and KTP 532 nm (SmartLite, DEKA, Italy. Samples were observed at OM LEICA DM 2000; margin alterations were evaluated through Leica Application Suite 3.4. Results. Epithelial and connective damages were assessed for each pathology with an average of 0.245 mm and a standard deviation of ±0.162 mm in mucoceles, 0.382 mm ± 0.149 mm in fibromas, 0.336 mm ± 0.106 mm in hyperkeratosis, 0.473 mm ± 0.105 mm in squamous hyperplasia, 0.182 mm in giant cell granuloma, and 0.149 mm in melanotic macula. Discussion. The histologic aspect of lesions influenced the response to laser, whereas the greater inflammation and cellularity were linked with the higher thermal signs. Many artifacts were also associated to histologic procedures. Conclusion. Both tested lasers permitted sure histologic diagnosis. However, it is suggested to enlarge biopsies of about 0.5 mm, to avoid thermal alterations, especially in inflammatory lesions like oral lichen planus.

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

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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.

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

Histologic evaluation of laser lipolysis comparing continuous wave vs pulsed lasers in an in vivo pig model.

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Levi, Jessica R; Veerappan, Anna; Chen, Bo; Mirkov, Mirko; Sierra, Ray; Spiegel, Jeffrey H

2011-01-01

To evaluate acute and delayed laser effects of subdermal lipolysis and collagen deposition using an in vivo pig model and to compare histologic findings in fatty tissue after continuous wave diode (CW) vs pulsed laser treatment. Three CW lasers (980, 1370, and 1470 nm) and 3 pulsed lasers (1064, 1320, and 1440 nm) were used to treat 4 Göttingen minipigs. Following administration of Klein tumescent solution, a laser cannula was inserted at the top of a 10 × 2.5-cm rectangle and was passed subdermally to create separate laser "tunnels." Temperatures at the surface and at intervals of 4-mm to 20-mm depths were recorded immediately after exposure and were correlated with skin injury. Full-thickness cutaneous biopsy specimens were obtained at 1 day, 1 week, and 1 month after exposure and were stained with hematoxylin-eosin and trichrome stain. Qualitative and semiquantitative histopathologic evaluations were performed with attention to vascular damage, lipolysis, and collagen deposition. Skin surface damage occurred at temperatures exceeding 46°C. Histologic examination at 1 day after exposure showed hemorrhage, fibrous collagen fiber coagulation, and adipocyte damage. Adipocytes surrounded by histiocytes, a marker of lipolysis, were present at 1 week and 1 month after exposure. Collagen deposition in subdermal fatty tissue and in reticular dermis of some specimens was noted at 1 week and had increased at 1 month. Tissue treated with CW laser at 1470 nm demonstrated greater hemorrhage and more histiocytes at damage sites than tissue treated with pulsed laser at 1440 nm. There was a trend toward more collagen deposition with pulsed lasers than with CW lasers, but this was not statistically significant. Histopathologic comparison between results of CW laser at 980 nm vs pulsed laser at 1064 nm showed the same trend. Hemorrhage differences may result from pulse duration variations. A theoretical calculation estimating temperature rise in vessels supported this

Evaluation of 3-D Laser Scanning Equipment : 2018 Final Report

Science.gov (United States)

2018-05-01

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 equ...

USE OF LASER SCANNING FOR CULTURAL HERITAGE DOCUMENTATION

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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.

Validation of optical coherence tomography in vivo using cryostat histology

International Nuclear Information System (INIS)

Gambichler, T; Moussa, G; Regeniter, P; Kasseck, C; Hofmann, M R; Bechara, F G; Sand, M; Altmeyer, P; Hoffmann, K

2007-01-01

We aimed to validate for the first time optical coherence tomography (OCT) measurements of epidermal thickness (ET) using cryopreparation for histology. OCT assessments of ET were performed on healthy skin using the algorithms as follows: first, peak-to-valley analysis of the A-scan (ET-OCT-V), second, line-traced image analysis of the B-scan (ET-OCT-IA). Histology was performed using cryostat sections which were also evaluated using the image analysis (ET-Histo). We selected 114 samples, including B-scans and corresponding histology, for method comparison between ET-OCT-IA and ET-Histo. Forty-two A-scans were available for method comparison between ET-OCT-V and ET-Histo. Bland and Altman plots revealed a marked bias with wide 95% limits of agreement for ET-OCT-V versus ET-Histo. Comparison of ET-OCT-IA versus ET-Histo revealed only a slight bias and narrow 95% limits of agreement. A-scan analysis for ET determination is linked to significant limitations and lacks agreement with histology. By contrast, we observed satisfactory agreement between ET-OCT-IA and ET-Histo indicating that both methods can be utilized interchangeably. OCT using the line-traced image analysis of the B-scan appears to be a valid and relatively practicable method for the determination of ET in vivo. Furthermore, the comparisons with the in vivo OCT profiles demonstrate that cryostat sectioning provides a better preservation of relative and absolute dimensions of skin layers than paraffin embedding. (note)

Histological and ultrastructural effect of an Nd:YAG pulsed laser beam on dental hard tissue and pulp

Science.gov (United States)

Vignato, Costantino; Vignato, Giuseppe; Nardelli, Antonella; Baldan, Arianna; Mason, Pier N.

1994-09-01

The purpose of this study was to determine histological and ultrastructural modifications produced by an Nd:YAG pulsed laser beam after an in vivo exposure of human molars. Using a Nd:YAG pulsed laser beam delivered by a 600 micrometers optical fiber and concurrent air and water cooling spray, 14 human third molars with artificial first class cavities were exposed at different power levels (6, 7, and 8 W). All the teeth were extracted at different time periods between 10 and 25 days and prepared for histological examination. The results of the histological examination showed no evidence of degeneration or necrosis of the pulpar tissue. Analysis of the dentinal surfaces after exposure demonstrated that the dentinal tubules are completely closed due to the melted dentin. In conclusion a Nd:YAG pulsed laser beam with an air and water cooling spray is safe for treatments of class I decay and no necrosis or degeneration of the pulp was found for laser powers of 6, 7, and 8 W.

Centimeter-scale MEMS scanning mirrors for high power laser application

Science.gov (United States)

Senger, F.; Hofmann, U.; v. Wantoch, T.; Mallas, C.; Janes, J.; Benecke, W.; Herwig, Patrick; Gawlitza, P.; Ortega-Delgado, M.; Grune, C.; Hannweber, J.; Wetzig, A.

2015-02-01

A higher achievable scan speed and the capability to integrate two scan axes in a very compact device are fundamental advantages of MEMS scanning mirrors over conventional galvanometric scanners. There is a growing demand for biaxial high speed scanning systems complementing the rapid progress of high power lasers for enabling the development of new high throughput manufacturing processes. This paper presents concept, design, fabrication and test of biaxial large aperture MEMS scanning mirrors (LAMM) with aperture sizes up to 20 mm for use in high-power laser applications. To keep static and dynamic deformation of the mirror acceptably low all MEMS mirrors exhibit full substrate thickness of 725 μm. The LAMM-scanners are being vacuum packaged on wafer-level based on a stack of 4 wafers. Scanners with aperture sizes up to 12 mm are designed as a 4-DOF-oscillator with amplitude magnification applying electrostatic actuation for driving a motor-frame. As an example a 7-mm-scanner is presented that achieves an optical scan angle of 32 degrees at 3.2 kHz. LAMM-scanners with apertures sizes of 20 mm are designed as passive high-Q-resonators to be externally excited by low-cost electromagnetic or piezoelectric drives. Multi-layer dielectric coatings with a reflectivity higher than 99.9 % have enabled to apply cw-laser power loads of more than 600 W without damaging the MEMS mirror. Finally, a new excitation concept for resonant scanners is presented providing advantageous shaping of intensity profiles of projected laser patterns without modulating the laser. This is of interest in lighting applications such as automotive laser headlights.

Comparison of tissue damage caused by various laser systems with tissue tolerable plasma by light and laser scan microscopy

International Nuclear Information System (INIS)

Vandersee, Staffan; Lademann, Jürgen; Richter, Heike; Patzelt, Alexa; Lange-Asschenfeldt, Bernhard

2013-01-01

Tissue tolerable plasma (TTP) represents a novel therapeutic method with promising capabilities in the field of dermatological interventions, in particular disinfection but also wound antisepsis and regeneration. The energy transfer by plasma into living tissue is not easily educible, as a variety of features such as the medium’s actual molecule-stream, the ions, electrons and free radicals involved, as well as the emission of ultraviolet, visible and infrared light contribute to its increasingly well characterized effects. Thus, relating possible adversary effects, especially of prolonged exposure to a single component of the plasma’s mode of action, is difficult. Until now, severe adverse events connected to plasma exposure have not been reported when conducted according to existing therapeutic protocols. In this study, we have compared the tissue damage-potential of CO 2 and dye lasers with TTP in a porcine model. After exposure of pig ear skin to the three treatment modalities, all specimens were examined histologically and by means of laser scan microscopy (LSM). Light microscopical tissue damage could only be shown in the case of the CO 2 laser, whereas dye laser and plasma treatment resulted in no detectable impairment of the specimens. In the case of TTP, LSM examination revealed only an impairment of the uppermost corneal layers of the skin, thus stressing its safety when used in vivo. (letter)

Analysis of the melanin distribution in different ethnic groups by in vivo laser scanning microscopy

International Nuclear Information System (INIS)

Antoniou, C; Lademann, J; Richter, H; Patzelt, A; Sterry, W; Astner, S; Zastrow, L; Koch, S

2009-01-01

The aim of this study was to determine whether Laser scanning confocal microscopy (LSM) is able to visualize differences in melanin content and distribution in different Skin Phototypes. The investigations were carried out on six healthy volunteers with Skin Phototypes II, IV, and VI. Representative skin samples of Skin Phototypes II, V, and VI were obtained for histological analysis from remaining tissue of skin grafts and were used for LSM-pathologic correlation. LSM evaluation showed significant differences in melanin distribution in Skin Phototypes II, IV, and VI, respectively. Based on the differences in overall reflectivity and image brightness, a visual evaluation scheme showed increasing brightness of the basal and suprabasal layers with increasing Skin Phototypes. The findings correlated well with histological analysis. The results demonstrate that LSM may serve as a promising adjunctive tool for real time assessment of melanin content and distribution in human skin, with numerous clinical applications and therapeutic and preventive implications

Application of Confocal Laser Scanning Microscopy in Biology and Medicine

OpenAIRE

I. A. Volkov; N. V. Frigo; L. F. Znamenskaya; O. R. Katunina

2014-01-01

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...

Photonic generation of ultra-wideband signals by direct current modulation on SOA section of an SOA-integrated SGDBR laser.

Science.gov (United States)

Lv, Hui; Yu, Yonglin; Shu, Tan; Huang, Dexiu; Jiang, Shan; Barry, Liam P

2010-03-29

Photonic ultra-wideband (UWB) pulses are generated by direct current modulation of a semiconductor optical amplifier (SOA) section of an SOA-integrated sampled grating distributed Bragg reflector (SGDBR) laser. Modulation responses of the SOA section of the laser are first simulated with a microwave equivalent circuit model. Simulated results show a resonance behavior indicating the possibility to generate UWB signals with complex shapes in the time domain. The UWB pulse generation is then experimentally demonstrated for different selected wavelength channels with an SOA-integrated SGDBR laser.

Safety, efficacy, predictability and stability of laser in situ keratomileusis (LASIK) with a 1000-Hz scanning spot excimer laser.

Science.gov (United States)

Khoramnia, Ramin; Salgado, Josefina P; Wuellner, Christian; Donitzky, Christof; Lohmann, Chris P; Winkler von Mohrenfels, Christoph

2012-09-01

To evaluate the safety, efficacy, predictability and stability of laser in situ keratomileusis (LASIK) with a 1000-Hz scanning spot excimer laser (Concept System 1000; WaveLight GmbH, Erlangen, Germany). LASIK was performed on twenty eyes with myopia or myopic astigmatism (mean spherical equivalent refraction: -3.97±1.72 dioptres (D); mean cylinder: -0.84±0.77 D) using a microkeratome for flap creation and the Concept System 1000 for photoablation. Patients were examined preoperatively as well as 1, 3 and 6 months after the treatment. Manifest sphere and cylinder, uncorrected (UCDVA) and best corrected (BCDVA) distance visual acuity, corneal topography and pachymetry were analysed. We observed no adverse events that might have been associated with the use of a repetition rate of 1000 Hz. All eyes maintained or had improved BCDVA at 6 months after treatment when compared to preoperative values. Six months after LASIK, UCDVA was 20/20 or better in 85% and 20/25 or better in 100% of the eyes. The spherical equivalent refraction was within ±0.50 D in 95% of the eyes at 6 months after surgery. The refraction stayed stable over time; 95% of the eyes changedLASIK with the prototype 1000-Hz excimer laser was safe, efficient and predictable. The postoperative refraction was stable over time. There were no specific clinical side-effects that might be associated with the use of such a high repetition rate. © 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.

Modifying a Rodenstock scanning laser ophthalmoscope for imaging densitometry.

Science.gov (United States)

Tornow, R P; Beuel, S; Zrenner, E

1997-08-01

The necessary modifications and technical requirements are described for using a commercially available scanning laser ophthalmoscope (Rodenstock Model 101 SLO) as an imaging densitometer to assess human photopigment distribution. The main requirements are a linear detector amplifier, fast shutters for the laser beams, and a trigger unit. Images must be compensated for varying laser intensity. Both rod and cone photopigments are measured with the 514-nm argon laser of the SLO. Discrimination is possible owing to the different spatial distribution. The cone pigment density peaks in the foveal center (D = 0.40) with a steep decrease with increasing eccentricity E (full width at half-maximum, 2.5 degrees ). Rod photopigment increases with increasing eccentricity (D = 0.23 for E = 11 degrees ). These values are in agreement with previous reported results obtained with scanning laser ophthalmoscopes specially designed for retinal densitometry and high stability.

Performance comparison of CO2 and diode lasers for deep-section concrete cutting

International Nuclear Information System (INIS)

Crouse, Philip L.; Li, Lin; Spencer, Julian T.

2004-01-01

Layer-by-layer laser machining with mechanical removal of vitrified dross between passes is a new technique with a demonstrated capability for deep-section cutting, not only of concrete, but of ceramic and refractory materials in general. For this application fairly low power densities are required. A comparison of experimental results using high-power CO 2 and diode lasers under roughly equivalent experimental conditions, cutting to depths of >100 mm, is presented. A marked improvement in cutting depth per pass is observed for the case of the diode laser. The increased cutting rate is rationalized in terms of the combined effects of coupling efficiency and beam shape

Histologic analyses on the response of the skin to 1,927-nm fractional thulium fiber laser treatment.

Science.gov (United States)

Kwon, In Ho; Bae, Youin; Yeo, Un-Cheol; Lee, Jin Yong; Kwon, Hyuck Hoon; Choi, Young Hee; Park, Gyeong-Hun

2018-02-01

The histologic responses to varied parameters of 1,927-nm fractional thulium fiber laser treatment have not yet been sufficiently elucidated. This study sought to evaluate histologic changes immediately after 1,927-nm fractional thulium fiber laser session at various parameters. The dorsal skin of Yucatan mini-pig was treated with 1,927-nm fractional thulium fiber laser at varied parameters, with or without skin drying. The immediate histologic changes were evaluated to determine the effects of varying laser parameters on the width and the depth of treated zones. The increase in the level of pulse energy widened the area of epidermal changes in the low power level, but increased the dermal penetration depth in the high power level. As the pulse energy level increased, the increase in the power level under the given pulse energy level more evidently made dermal penetration deeper and the treatment area smaller. Skin drying did not show significant effects on epidermal changes, but evidently increased the depth of dermal denaturation under both high and low levels of pulse energy. These results may provide important information to establish treatment parameters of the 1,927-nm fractional thulium fiber laser for various skin conditions.

SOME ASPECTS OF SCANNING LASER OPHTHALMOSCOPY IN THE DIAGNOSTICS OF OPHTHALMOPATHOLOGY

Directory of Open Access Journals (Sweden)

S. A. Kochergin

2017-01-01

Full Text Available The exact diagnosis of the fundus pathology requires the most modern equipment use. This is mandatory for the selection of the most complete therapy and monitoring of ongoing treatment. At present, the method of scanning laser ophthalmoscopy is widely spread. However, for the earliest detection of the smallest pathological changes, data of the normal ocular fundus state using a scanning laser ophthalmoscope is necessary. Thus, the purpose of our research becomes relevant. Purpose: to give a characteristic of the fundus in patients without concomitant pathology with using various modes of a scanning laser ophthalmoscope. Patients and methods. 116 people (232 eyes at the age from 17 to 71 years (mean age 32.5±12 years were examined. The patients were divided into two groups. Group I: 81 patients (162 eyes with different ophthalmopathology. Group II: 35 people (70 eyes — practically healthy and did not have an anamnesis of consulting an ophthalmologist. Diagnosis of the patients’ fundus was performed using a scanning laser ophthalmoscopy with retro-mode imaging and autofluorescence registration. Results. After the conducted research features and regularities of the reflectivity distribution of laser beams from the fundus structures are revealed. Also a characteristic of various anatomical formations and zones of the fundus in the normal conditions is given when examined by a scanning laser ophthalmoscope. An algorithm for examining patients and analyzing the images was developed. Conclusion. The use of scanning laser ophthalmoscopy made possible to take a fresh look at the algorithms of diagnosing patients with fundus pathology. Understanding the normal conditions ofundus allowed an earlier detection of the smallest pathological changes in the retina. 

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.

PINPIN a-Si:H based structures for X-ray image detection using the laser scanning technique

Energy Technology Data Exchange (ETDEWEB)

Fernandes, M., E-mail: mfernandes@isel.pt [Electronics Telecommunication and Computer Dept., ISEL, R.Conselheiro Emídio Navarro, 1959-007 Lisboa (Portugal); CTS-UNINOVA Quinta da Torre, Monte da Caparica, 2829-516 Caparica (Portugal); Vygranenko, Y.; Vieira, M. [Electronics Telecommunication and Computer Dept., ISEL, R.Conselheiro Emídio Navarro, 1959-007 Lisboa (Portugal); CTS-UNINOVA Quinta da Torre, Monte da Caparica, 2829-516 Caparica (Portugal)

2015-05-01

Highlights: • We present novel structure for X-ray image sensor based on the laser scanned technique. • Amorphous silicon based tandem structure characterization results are presented and discussed. • Results from preliminary tests of the imaging application are promising for very large area image sensing. - Abstract: Conventional film based X-ray imaging systems are being replaced by their digital equivalents. Different approaches are being followed by considering direct or indirect conversion, with the later technique dominating. The typical, indirect conversion, X-ray panel detector uses a phosphor for X-ray conversion coupled to a large area array of amorphous silicon based optical sensors and a couple of switching thin film transistors (TFT). The pixel information can then be readout by switching the correspondent line and column transistors, routing the signal to an external amplifier. In this work we follow an alternative approach, where the electrical switching performed by the TFT is replaced by optical scanning using a low power laser beam and a sensing/switching PINPIN structure, thus resulting in a simpler device. The optically active device is a PINPIN array, sharing both front and back electrical contacts, deposited over a glass substrate. During X-ray exposure, each sensing side photodiode collects photons generated by the scintillator screen (560 nm), charging its internal capacitance. Subsequently a laser beam (445 nm) scans the switching diodes (back side) retrieving the stored charge in a sequential way, reconstructing the image. In this paper we present recent work on the optoelectronic characterization of the PINPIN structure to be incorporated in the X-ray image sensor. The results from the optoelectronic characterization of the device and the dependence on scanning beam parameters are presented and discussed. Preliminary results of line scans are also presented.

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)

Practicable methods for histological section thickness measurement in quantitative stereological analyses.

Science.gov (United States)

Matenaers, Cyrill; Popper, Bastian; Rieger, Alexandra; Wanke, Rüdiger; Blutke, Andreas

2018-01-01

The accuracy of quantitative stereological analysis tools such as the (physical) disector method substantially depends on the precise determination of the thickness of the analyzed histological sections. One conventional method for measurement of histological section thickness is to re-embed the section of interest vertically to its original section plane. The section thickness is then measured in a subsequently prepared histological section of this orthogonally re-embedded sample. However, the orthogonal re-embedding (ORE) technique is quite work- and time-intensive and may produce inaccurate section thickness measurement values due to unintentional slightly oblique (non-orthogonal) positioning of the re-embedded sample-section. Here, an improved ORE method is presented, allowing for determination of the factual section plane angle of the re-embedded section, and correction of measured section thickness values for oblique (non-orthogonal) sectioning. For this, the analyzed section is mounted flat on a foil of known thickness (calibration foil) and both the section and the calibration foil are then vertically (re-)embedded. The section angle of the re-embedded section is then calculated from the deviation of the measured section thickness of the calibration foil and its factual thickness, using basic geometry. To find a practicable, fast, and accurate alternative to ORE, the suitability of spectral reflectance (SR) measurement for determination of plastic section thicknesses was evaluated. Using a commercially available optical reflectometer (F20, Filmetrics®, USA), the thicknesses of 0.5 μm thick semi-thin Epon (glycid ether)-sections and of 1-3 μm thick plastic sections (glycolmethacrylate/ methylmethacrylate, GMA/MMA), as regularly used in physical disector analyses, could precisely be measured within few seconds. Compared to the measured section thicknesses determined by ORE, SR measures displayed less than 1% deviation. Our results prove the applicability

Fractional CO₂ laser treatment of caesarean section scars

DEFF Research Database (Denmark)

Karmisholt, Katrine E; Taudorf, Elisabeth H; Wulff, Camilla B

2017-01-01

BACKGROUND AND OBJECTIVES: Caesarean section (c-section) scars can be pose functional and cosmetic challenges and ablative fractional laser (AFXL) treatment may offer benefit to patients. We evaluated textural and color changes over time in AFXL-treated versus untreated control scars. MATERIALS...... AND METHODS: A randomized, controlled, intra-individual split-scar trial with three sessions of AFXL-treatments for mature c-section scars. Settings of AFXL were adjusted to each individual scar. End-points were blinded on-site clinical evaluations at 1, 3, and 6 months follow-up (Patient and Observer Scar...... Assessment Scale [POSAS] and Vancouver Scar Scale [VSS]), blinded photo-evaluations, reflectance measurements, tissue histology, and patients satisfaction. RESULTS: Eleven of 12 patients completed the study. At 1 month follow-up, AFXL-treated scars were significantly improved in pliability (POSAS P = 0...

Volumetry of human taste buds using laser scanning microscopy.

Science.gov (United States)

Just, T; Srur, E; Stachs, O; Pau, H W

2009-10-01

In vivo laser scanning confocal microscopy is a relatively new, non-invasive method for assessment of oral cavity epithelia. The penetration depth of approximately 200-400 microm allows visualisation of fungiform papillae and their taste buds. This paper describes the technique of in vivo volumetry of human taste buds. Confocal laser scanning microscopy used a diode laser at 670 nm for illumination. Digital laser scanning confocal microscopy equipment consisted of the Heidelberg Retina Tomograph HRTII and the Rostock Cornea Module. Volume scans of fungiform papillae were used for three-dimensional reconstruction of the taste bud. This technique supplied information on taste bud structure and enabled measurement and calculation of taste bud volume. Volumetric data from a 23-year-old man over a nine-day period showed only a small deviation in values. After three to four weeks, phenomenological changes in taste bud structures were found (i.e. a significant increase in volume, followed by disappearance of the taste bud and appearance of a new taste bud). The data obtained indicate the potential application of this non-invasive imaging modality: to evaluate variation of taste bud volume in human fungiform papillae with ageing; to study the effects of chorda tympani nerve transection on taste bud volume; and to demonstrate recovery of taste buds in patients with a severed chorda tympani nerve who show recovery of gustatory sensibility after surgery.

Distance measurement using frequency scanning interferometry with mode-hoped laser

Science.gov (United States)

Medhat, M.; Sobee, M.; Hussein, H. M.; Terra, O.

2016-06-01

In this paper, frequency scanning interferometry is implemented to measure distances up to 5 m absolutely. The setup consists of a Michelson interferometer, an external cavity tunable diode laser, and an ultra-low expansion (ULE) Fabry-Pérot (FP) cavity to measure the frequency scanning range. The distance is measured by acquiring simultaneously the interference fringes from, the Michelson and the FP interferometers, while scanning the laser frequency. An online fringe processing technique is developed to calculate the distance from the fringe ratio while removing the parts result from the laser mode-hops without significantly affecting the measurement accuracy. This fringe processing method enables accurate distance measurements up to 5 m with measurements repeatability ±3.9×10-6 L. An accurate translation stage is used to find the FP cavity free-spectral-range and therefore allow accurate measurement. Finally, the setup is applied for the short distance calibration of a laser distance meter (LDM).

Continuous section extraction and over-underbreak detection of tunnel based on 3D laser technology and image analysis

Science.gov (United States)

Wang, Weixing; Wang, Zhiwei; Han, Ya; Li, Shuang; Zhang, Xin

2015-03-01

Over Underbreak detection of road and solve the problemof the roadway data collection difficulties, this paper presents a new method of continuous section extraction and Over Underbreak detection of road based on 3D laser scanning technology and image processing, the method is divided into the following three steps: based on Canny edge detection, local axis fitting, continuous extraction section and Over Underbreak detection of section. First, after Canny edge detection, take the least-squares curve fitting method to achieve partial fitting in axis. Then adjust the attitude of local roadway that makes the axis of the roadway be consistent with the direction of the extraction reference, and extract section along the reference direction. Finally, we compare the actual cross-sectional view and the cross-sectional design to complete Overbreak detected. Experimental results show that the proposed method have a great advantage in computing costs and ensure cross-section orthogonal intercept terms compared with traditional detection methods.

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...... procedure for the sFPI-LDV and investigate the effect of different degrees of laser frequency noise between the FL and the SL on the velocimeter’s performance...

Scanning electron microscopy of vascular corrosion casts and histologic examination of pulmonary microvasculature in dogs with dirofilariosis.

Science.gov (United States)

Ninomiya, Hiroyoshi; Wakao, Yoshito

2002-11-01

To characterize structural changes in pulmonary vessels of dogs with dirofilariosis. 8 dogs with dirofilariosis and 2 unaffected control dogs. Pulmonary artery pressure was measured in affected dogs, and dogs then were euthanatized. Scanning electron microscopy was used to examine vascular corrosion casts of pulmonary vasculature. Tissue sections of pulmonary vasculature were evaluated by use of histologic examination. Pulmonary artery pressure was higher in dogs with severely affected pulmonary vessels. In tissue sections, dilatation, as well as lesions in the tunica intima and proliferative lesions resulting in constriction or obstruction, were frequently observed in branches of the pulmonary artery. Numerous dilated bronchial arteries were observed around affected pulmonary arteries. Hyperplastic venous sphincters were observed in small pulmonary veins and venules. In corrosion casts, affected pulmonary lobar arteries had dilatation, pruning, abnormal tapering, constriction, and obstruction. In small arteries and arterioles, surface structures representing aneurisms and edema were seen. Bronchial arteries were well developed and extremely dilated, and they formed numerous anastomoses with pulmonary arteries at all levels, from the pulmonary trunk to peripheral vessels. Capillaries in the lungs were dilated with little structural change. Small pulmonary veins and venules had irregular annular constrictions that were caused by hyperplastic smooth muscle cells of venous sphincters. Scanning electron microscopy of microvascular casts delineated links between the bronchial and pulmonary circulations in dogs with dirofilariosis. Results of scanning electron microscopy provided a structural explanation for the development of pulmonary circulatory disturbances and pulmonary hypertension in dogs affected by dirofilariosis.

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.

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.

An Equivalent cross-section Framework for improving computational efficiency in Distributed Hydrologic Modelling

Science.gov (United States)

Khan, Urooj; Tuteja, Narendra; Ajami, Hoori; Sharma, Ashish

2014-05-01

While the potential uses and benefits of distributed catchment simulation models is undeniable, their practical usage is often hindered by the computational resources they demand. To reduce the computational time/effort in distributed hydrological modelling, a new approach of modelling over an equivalent cross-section is investigated where topographical and physiographic properties of first-order sub-basins are aggregated to constitute modelling elements. To formulate an equivalent cross-section, a homogenization test is conducted to assess the loss in accuracy when averaging topographic and physiographic variables, i.e. length, slope, soil depth and soil type. The homogenization test indicates that the accuracy lost in weighting the soil type is greatest, therefore it needs to be weighted in a systematic manner to formulate equivalent cross-sections. If the soil type remains the same within the sub-basin, a single equivalent cross-section is formulated for the entire sub-basin. If the soil type follows a specific pattern, i.e. different soil types near the centre of the river, middle of hillslope and ridge line, three equivalent cross-sections (left bank, right bank and head water) are required. If the soil types are complex and do not follow any specific pattern, multiple equivalent cross-sections are required based on the number of soil types. The equivalent cross-sections are formulated for a series of first order sub-basins by implementing different weighting methods of topographic and physiographic variables of landforms within the entire or part of a hillslope. The formulated equivalent cross-sections are then simulated using a 2-dimensional, Richards' equation based distributed hydrological model. The simulated fluxes are multiplied by the weighted area of each equivalent cross-section to calculate the total fluxes from the sub-basins. The simulated fluxes include horizontal flow, transpiration, soil evaporation, deep drainage and soil moisture. To assess

Additive Manufacturing of IN100 Superalloy Through Scanning Laser Epitaxy for Turbine Engine Hot-Section Component Repair: Process Development, Modeling, Microstructural Characterization, and Process Control

Science.gov (United States)

Acharya, Ranadip; Das, Suman

2015-09-01

This article describes additive manufacturing (AM) of IN100, a high gamma-prime nickel-based superalloy, through scanning laser epitaxy (SLE), aimed at the creation of thick deposits onto like-chemistry substrates for enabling repair of turbine engine hot-section components. SLE is a metal powder bed-based laser AM technology developed for nickel-base superalloys with equiaxed, directionally solidified, and single-crystal microstructural morphologies. Here, we combine process modeling, statistical design-of-experiments (DoE), and microstructural characterization to demonstrate fully metallurgically bonded, crack-free and dense deposits exceeding 1000 μm of SLE-processed IN100 powder onto IN100 cast substrates produced in a single pass. A combined thermal-fluid flow-solidification model of the SLE process compliments DoE-based process development. A customized quantitative metallography technique analyzes digital cross-sectional micrographs and extracts various microstructural parameters, enabling process model validation and process parameter optimization. Microindentation measurements show an increase in the hardness by 10 pct in the deposit region compared to the cast substrate due to microstructural refinement. The results illustrate one of the very few successes reported for the crack-free deposition of IN100, a notoriously "non-weldable" hot-section alloy, thus establishing the potential of SLE as an AM method suitable for hot-section component repair and for future new-make components in high gamma-prime containing crack-prone nickel-based superalloys.

Lidar cross-sections of soot fractal aggregates: Assessment of equivalent-sphere models

Science.gov (United States)

Ceolato, Romain; Gaudfrin, Florian; Pujol, Olivier; Riviere, Nicolas; Berg, Matthew J.; Sorensen, Christopher M.

2018-06-01

This work assesses the ability of equivalent-sphere models to reproduce the optical properties of soot aggregates relevant for lidar remote sensing, i.e. the backscattering and extinction cross sections. Lidar cross-sections are computed with a spectral discrete dipole approximation model over the visible-to-infrared (400-5000 nm) spectrum and compared with equivalent-sphere approximations. It is shown that the equivalent-sphere approximation, applied to fractal aggregates, has a limited ability to calculate such cross-sections well. The approximation should thus be used with caution for the computation of broadband lidar cross-sections, especially backscattering, at small and intermediate wavelengths (e.g. UV to visible).

Extracting Rail Track Geometry from Static Terrestrial Laser Scans for Monitoring Purposes

Directory of Open Access Journals (Sweden)

A. Soni

2014-06-01

Full Text Available This paper presents the capabilities of detecting relevant geometry of railway track for monitoring purposes from static terrestrial laser scanning (TLS systems at platform level. The quality of the scans from a phased based scanner (Scanner A and a hybrid timeof- flight scanner (Scanner B are compared by fitting different sections of the track profile to its matching standardised rail model. The various sections of track investigated are able to fit to the model with an RMS of less than 3 mm. Both scanners show that once obvious noise and artefacts have been removed from the data, the most confident fit of the point cloud to the model is the section closest to the scanner position. The results of the fit highlight the potential to use this method as a bespoke track monitoring tool during major redevelopment projects where traditional methods, such as robotic total stations, results in missed information, for example due to passing trains or knocked prisms and must account for offset target locations to compute track parameters.

PINPIN a-Si:H based structures for X-ray image detection using the laser scanning technique

Science.gov (United States)

Fernandes, M.; Vygranenko, Y.; Vieira, M.

2015-05-01

Conventional film based X-ray imaging systems are being replaced by their digital equivalents. Different approaches are being followed by considering direct or indirect conversion, with the later technique dominating. The typical, indirect conversion, X-ray panel detector uses a phosphor for X-ray conversion coupled to a large area array of amorphous silicon based optical sensors and a couple of switching thin film transistors (TFT). The pixel information can then be readout by switching the correspondent line and column transistors, routing the signal to an external amplifier. In this work we follow an alternative approach, where the electrical switching performed by the TFT is replaced by optical scanning using a low power laser beam and a sensing/switching PINPIN structure, thus resulting in a simpler device. The optically active device is a PINPIN array, sharing both front and back electrical contacts, deposited over a glass substrate. During X-ray exposure, each sensing side photodiode collects photons generated by the scintillator screen (560 nm), charging its internal capacitance. Subsequently a laser beam (445 nm) scans the switching diodes (back side) retrieving the stored charge in a sequential way, reconstructing the image. In this paper we present recent work on the optoelectronic characterization of the PINPIN structure to be incorporated in the X-ray image sensor. The results from the optoelectronic characterization of the device and the dependence on scanning beam parameters are presented and discussed. Preliminary results of line scans are also presented.

Bus bays inventory using a terrestrial laser scanning system

Directory of Open Access Journals (Sweden)

Bobkowska Katarzyna

2017-01-01

Full Text Available This article presents the use of laser scanning technology for the assessment of bus bay geo-location. Ground laser scanning is an effective tool for collecting three-dimensional data. Moreover, the analysis of a point cloud dataset can be a source of a lot of information. The authors have outlined an innovative use of data collection and analysis using the TLS regarding information on the flatness of bus bays. The results were finalized in the form of colour three-dimensional maps of deviations and pavement type.

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.

Safety, efficacy, and predictability of laser in situ keratomileusis to correct myopia or myopic astigmatism with a 750 Hz scanning-spot laser system.

Science.gov (United States)

Tomita, Minoru; Watabe, Miyuki; Yukawa, Satoshi; Nakamura, Nobuo; Nakamura, Tadayuki; Magnago, Thomas

2014-02-01

To evaluate the clinical outcomes of laser in situ keratomileusis (LASIK) to correct myopia or myopic astigmatism using the Amaris 750S 750 Hz excimer laser. Private LASIK center, Tokyo, Japan. Case series. Patients with myopia or myopic astigmatism (spherical equivalent -0.50 to -11.63 diopters [D]), a corrected distance visual acuity (CDVA) of 20/20 or better, and an estimated residual bed thickness of 300 μm or more had LASIK using the aspheric aberration-free ablation profile of the 750 Hz scanning-spot laser and the Femto LDV Crystal Line femtosecond laser for flap creation. Study parameters included uncorrected distance visual acuity (UDVA), CDVA, manifest refraction, astigmatism, and higher-order aberrations (HOAs). The study included 1280 eyes (685 patients). At 3 months, 96.6% of eyes had a UDVA of 20/20 or better and 99.1% had 20/32 or better; 94.1% of eyes were within ± 0.50 D of the intended correction and 98.9% were within ± 1.00 D; 89.7% of eyes had no residual cylinder and 96.0% had a postoperative astigmatism of less than 0.50 D. All eyes had a postoperative CDVA of 20/20 or better. The HOAs increased postoperatively (PLaser in situ keratomileusis with the 750 Hz scanning-spot laser was safe, effective, and predictable. No specific clinical side effects that might be associated with a high repetition rate occurred. Mr. Magnago is an employee of Schwind eye-tech-solutions GmbH. No other author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

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.

Section Preequating under the Equivalent Groups Design without IRT

Science.gov (United States)

Guo, Hongwen; Puhan, Gautam

2014-01-01

In this article, we introduce a section preequating (SPE) method (linear and nonlinear) under the randomly equivalent groups design. In this equating design, sections of Test X (a future new form) and another existing Test Y (an old form already on scale) are administered. The sections of Test X are equated to Test Y, after adjusting for the…

Fluence scan: an unexplored property of a laser beam

International Nuclear Information System (INIS)

Chalupsky, Jaromir; Hajkova, Vera; Burian, Tomas; Juha, Libor; Polcar, Tomas; Gaudin, Jerome; Nagasono, Mitsuru; Yabashi, Makina; Sobierajski, Ryszard; Krzywinski, Jacek

2013-01-01

We present an extended theoretical background of so-called fluence scan (f-scan or F-scan) method, which is frequently being used for offline characterization of focused short-wavelength (EUV, soft X-ray, and hard X-ray) laser beams [J. Chalupsky et al., Opt. Express 18, 27836 (2010)]. The method exploits ablative imprints in various solids to visualize iso-fluence beam contours at different fluence and/or clip levels. An f-scan curve (clip level as a function of the corresponding iso-fluence contour area) can be generated for a general non-Gaussian beam. As shown in this paper, fluence scan encompasses important information about energy distribution within the beam profile, which may play an essential role in laser-matter interaction research employing intense non-ideal beams. Here we for the first time discuss fundamental properties of the f-scan function and its inverse counterpart (if-scan). Furthermore, we extensively elucidate how it is related to the effective beam area, energy distribution, and to the so called Liu's dependence [J.M. Liu, Opt. Lett. 7, 196 (1982)]. A new method of the effective area evaluation based on weighted inverse f-scan fit is introduced and applied to real data obtained at the SCSS (SPring-8 Compact SASE Source) facility. (authors)

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.

AUTOMATIC RAILWAY POWER LINE EXTRACTION USING MOBILE LASER SCANNING DATA

Directory of Open Access Journals (Sweden)

S. Zhang

2016-06-01

Full Text Available Research on power line extraction technology using mobile laser point clouds has important practical significance on railway power lines patrol work. In this paper, we presents a new method for automatic extracting railway power line from MLS (Mobile Laser Scanning data. Firstly, according to the spatial structure characteristics of power-line and trajectory, the significant data is segmented piecewise. Then, use the self-adaptive space region growing method to extract power lines parallel with rails. Finally use PCA (Principal Components Analysis combine with information entropy theory method to judge a section of the power line whether is junction or not and which type of junction it belongs to. The least squares fitting algorithm is introduced to model the power line. An evaluation of the proposed method over a complicated railway point clouds acquired by a RIEGL VMX450 MLS system shows that the proposed method is promising.

RADIOMETRIC CALIBRATION OF AIRBORNE LASER SCANNING DATA

OpenAIRE

Pilarska Magdalena

2016-01-01

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) th...

High-resolution adaptive optics scanning laser ophthalmoscope with multiple deformable mirrors

Science.gov (United States)

Chen, Diana C.; Olivier, Scot S.; Jones; Steven M.

2010-02-23

An adaptive optics scanning laser ophthalmoscopes is introduced to produce non-invasive views of the human retina. The use of dual deformable mirrors improved the dynamic range for correction of the wavefront aberrations compared with the use of the MEMS mirror alone, and improved the quality of the wavefront correction compared with the use of the bimorph mirror alone. The large-stroke bimorph deformable mirror improved the capability for axial sectioning with the confocal imaging system by providing an easier way to move the focus axially through different layers of the retina.

Quality Assurance By Laser Scanning And Imaging Techniques

Science.gov (United States)

SchmalfuB, Harald J.; Schinner, Karl Ludwig

1989-03-01

Laser scanning systems are well established in the world of fast industrial in-process quality inspection systems. The materials inspected by laser scanning systems are e.g. "endless" sheets of steel, paper, textile, film or foils. The web width varies from 50 mm up to 5000 mm or more. The web speed depends strongly on the production process and can reach several hundred meters per minute. The continuous data flow in one of different channels of the optical receiving system exceeds ten Megapixels/sec. Therefore it is clear that the electronic evaluation system has to process these data streams in real time and no image storage is possible. But sometimes (e.g. first installation of the system, change of the defect classification) it would be very helpful to have the possibility for a visual look on the original, i.e. not processed sensor data. At first we show the principle set up of a standard laser scanning system. Then we will introduce a large image memory especially designed for the needs of high-speed inspection sensors. This image memory co-operates with the standard on-line evaluation electronics and provides therefore an easy comparison between processed and non-processed data. We will discuss the basic system structure and we will show the first industrial results.

Examination of the skin barrier repair/wound healing process using a living skin equivalent model and matrix-assisted laser desorption-ionization-mass spectrometry imaging.

Science.gov (United States)

Lewis, E E L; Barrett, M R T; Freeman-Parry, L; Bojar, R A; Clench, M R

2018-04-01

Examination of the skin barrier repair/wound healing process using a living skin equivalent (LSE) model and matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to identify lipids directly involved as potential biomarkers. These biomarkers may be used to determine whether an in vivo wound is going to heal for example if infected. An in vitro LSE model was wounded with a scalpel blade and assessed at day 4 post-wounding by histology and MALDI-MSI. Samples were sectioned at wound site and were either formalin-fixed paraffin-embedded (FFPE) for histology or snapped frozen (FF) for MSI analysis. The combination of using an in vitro wounded skin model with MSI allowed the identification of lipids involved in the skin barrier repair/wound healing process. The technique was able to highlight lipids directly in the wound site and distinguish differences in lipid distribution between the epidermis and wound site. This novel method of coupling an in vitro LSE with MSI allowed in-depth molecular analysis of the skin barrier repair/wound healing process. The technique allowed the identification of lipids directly involved in the skin barrier repair/wound healing process, indicating these biomarkers may be potentially be used within the clinic. These biomarkers will help to determine, which stage of the skin barrier repair/wound healing process the wound is in to provide the best treatment. © 2018 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Method for accurate registration of tissue autofluorescence imaging data with corresponding histology: a means for enhanced tumor margin assessment

Science.gov (United States)

Unger, Jakob; Sun, Tianchen; Chen, Yi-Ling; Phipps, Jennifer E.; Bold, Richard J.; Darrow, Morgan A.; Ma, Kwan-Liu; Marcu, Laura

2018-01-01

An important step in establishing the diagnostic potential for emerging optical imaging techniques is accurate registration between imaging data and the corresponding tissue histopathology typically used as gold standard in clinical diagnostics. We present a method to precisely register data acquired with a point-scanning spectroscopic imaging technique from fresh surgical tissue specimen blocks with corresponding histological sections. Using a visible aiming beam to augment point-scanning multispectral time-resolved fluorescence spectroscopy on video images, we evaluate two different markers for the registration with histology: fiducial markers using a 405-nm CW laser and the tissue block's outer shape characteristics. We compare the registration performance with benchmark methods using either the fiducial markers or the outer shape characteristics alone to a hybrid method using both feature types. The hybrid method was found to perform best reaching an average error of 0.78±0.67 mm. This method provides a profound framework to validate diagnostical abilities of optical fiber-based techniques and furthermore enables the application of supervised machine learning techniques to automate tissue characterization.

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.

Laser sintering of metal powders on top of sintered layers under multiple-line laser scanning

International Nuclear Information System (INIS)

Xiao Bin; Zhang Yuwen

2007-01-01

A three-dimensional numerical model for multiple-line sintering of loose powders on top of multiple sintered layers under the irradiation of a moving Gaussian laser beam is carried out. The overlaps between vertically deposited layers and adjacent lines which strengthen bonding are taken into account. The energy equation is formulated using the temperature transforming model and solved by the finite volume method. The effects of the number of the existing sintered layers, porosity and initial temperature coupled with the optimal combination laser intensity and scanning velocity are presented. The results show that the liquid pool moves slightly towards the negative scanning direction and the shape of the liquid pool becomes shallower with higher scanning velocity. A higher laser intensity is needed to achieve the required overlaps when the number of the existing sintered layers increases. Increasing porosity or initial temperature enhances the sintering process and thus less intensity is needed for the overlap requirement

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

Scanning laser ophthalmoscope design with adaptive optics

OpenAIRE

Laut, SP; Jones, SM; Olivier, SS; Werner, JS

2005-01-01

A design for a high-resolution scanning instrument is presented for in vivo imaging of the human eye at the cellular scale. This system combines adaptive optics technology with a scanning laser ophthalmoscope (SLO) to image structures with high lateral (∼2 μm) resolution. In this system, the ocular wavefront aberrations that reduce the resolution of conventional SLOs are detected by a Hartmann-Shack wavefront sensor, and compensated with two deformable mirrors in a closed-loop for dynamic cor...

Recommendations for the design and the installation of large laser scanning microscopy systems

Science.gov (United States)

Helm, P. Johannes

2012-03-01

Laser Scanning Microscopy (LSM) has since the inventions of the Confocal Scanning Laser Microscope (CLSM) and the Multi Photon Laser Scanning Microscope (MPLSM) developed into an essential tool in contemporary life science and material science. The market provides an increasing number of turn-key and hands-off commercial LSM systems, un-problematic to purchase, set up and integrate even into minor research groups. However, the successful definition, financing, acquisition, installation and effective use of one or more large laser scanning microscopy systems, possibly of core facility character, often requires major efforts by senior staff members of large academic or industrial units. Here, a set of recommendations is presented, which are helpful during the process of establishing large systems for confocal or non-linear laser scanning microscopy as an effective operational resource in the scientific or industrial production process. Besides the description of technical difficulties and possible pitfalls, the article also illuminates some seemingly "less scientific" processes, i.e. the definition of specific laboratory demands, advertisement of the intention to purchase one or more large systems, evaluation of quotations, establishment of contracts and preparation of the local environment and laboratory infrastructure.

Research on Radar Cross Section Measurement Based on Near-field Imaging of Cylindrical Scanning

Directory of Open Access Journals (Sweden)

Xing Shu-guang

2015-04-01

Full Text Available A new method of Radar Cross Section (RCS measurement based on near-field imaging of cylindrical scanning surface is proposed. The method is based on the core assumption that the target consists of ideal isotropic scattered centers. Three-dimensional radar scattered images are obtained by using the proposed method, and then to obtain the RCS of the target, the scattered far field is calculated by summing the fields generated by the equivalent scattered centers. Not only three dimensional radar reflectivity images but also the RCS of targets in certain three dimensional angle areas can be obtained. Compared with circular scanning that can only obtain twodimensional radar reflectivity images and RCS results in two-dimensional angle areas, cylindrical scanning can provide more information about the scattering properties of the targets. The method has strong practicability and its validity is verified by simulations.

Early intraocular pressure change after peripheral iridotomy with ultralow fluence pattern scanning laser and Nd:YAG laser in primary angle-closure suspect: Kowloon East Pattern Scanning Laser Study Report No. 3.

Science.gov (United States)

Chan, Jeffrey Chi Wang; Choy, Bonnie Nga Kwan; Chan, Orlando Chia Chieh; Li, Kenneth Kai Wang

2018-02-01

Our purpose was to assess the early intraocular pressure (IOP) changes of ultralow fluence laser iridotomy using pattern scanning laser followed by neodymium:yttrium-aluminum-gamet (Nd:YAG) laser. This is a prospective interventional study. Thirty-three eyes of 33 adult Chinese primary angle-closure suspect subjects were recruited for prophylactic laser peripheral iridotomy. Sequential laser peripheral iridotomy was performed using pattern scanning laser followed by Nd:YAG laser. Visual acuity (VA) and IOP were measured before treatment, at 1 h, 1 day, 1 week, 1 month, 3 months and 6 months after laser. Laser energy used and complications were documented. Corneal endothelial cell count was examined at baseline and 6 months. Patency of the iridotomy was assessed at each follow-up visit. All subjects achieved patent iridotomy in a single session. The mean energy used was 0.335+/-0.088 J for the pattern scanning laser, and 4.767+/-5.780 mJ for the Nd:YAG laser. The total mean energy was 0.339+/-0.089 J. None of the eyes developed a clinically significant IOP spike (≥ 8 mmHg) at 1 h and 1 day after laser use. Only four eyes developed higher IOP at 1 h and all were ≤3 mmHg compared to baseline. The mean IOP was 13.8+/-2.5 mmHg at 1 h and 11.5+/-2.2 mmHg at 1 day, both were significantly lower than baseline (15.8+/-2.1 mmHg) (P laser compared to baseline (0.23 vs 0.26). There was also no statistically significant difference in mean VA at other follow-up visits compared to baseline. Peripheral iridotomy closure was encountered in two (6.1%) eyes, one at 1 month and another at 6 months follow-up. There were no complications including hyphema, peripheral anterior synechia formation nor prolonged inflammation throughout the follow-up period. There was no significant loss in corneal endothelial cell counts at 6 months (2255+/-490) compared to baseline (2303+/-386) (P = 0.347). Sequential LPI using an ultralow fluence pattern scanning laser

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...

Improved method of producing satisfactory sections of whole eyeball by routine histology.

Science.gov (United States)

Arko-Boham, Benjamin; Ahenkorah, John; Hottor, Bismarck Afedo; Dennis, Esther; Addai, Frederick Kwaku

2014-02-01

To overcome the loss of structural integrity when eyeball sections are prepared by wax embedding, we experimentally modified the routine histological procedure and report satisfactorily well-preserved antero-posterior sections of whole eyeballs for teaching/learning purposes. Presently histological sections of whole eyeballs are not readily available because substantial structural distortions attributable to variable consistency of tissue components (and their undesired differential shrinkage) result from routine processing. Notably, at the dehydration stage of processing, the soft, gel-like vitreous humor considerably shrinks relative to the tough fibrous sclera causing collapse of the ocular globe. Additionally, the combined effects of fixation, dehydration, and embedding at 60°C renders the eye lens too hard for microtome slicing at thicknesses suitable for light microscopy. We satisfactorily preserved intact antero-posterior sections of eyeballs via routine paraffin wax processing procedure entailing two main modifications; (i) careful needle aspiration of vitreous humor and replacement with molten wax prior to wax infiltration; (ii) softening of lens in trimmed wax block by placing a drop of concentrated liquid phenol on it for 3 h during microtomy. These variations of the routine histological method produced intact whole eyeball sections with retinal detachment as the only structural distortion. Intact sections of the eyeball obtained compares well with the laborious, expensive, and 8-week long celloidin method. Our method has wider potential usability than costly freeze drying method which requires special skills and equipment (cryotome) and does not produce whole eyeball sections. Copyright © 2013 Wiley Periodicals, Inc.

Codification of scan path parameters and development of perimeter scan strategies for 3D bowl-shaped laser forming

Science.gov (United States)

Tavakoli, A.; Naeini, H. Moslemi; Roohi, Amir H.; Gollo, M. Hoseinpour; Shahabad, Sh. Imani

2018-01-01

In the 3D laser forming process, developing an appropriate laser scan pattern for producing specimens with high quality and uniformity is critical. This study presents certain principles for developing scan paths. Seven scan path parameters are considered, including: (1) combined linear or curved path; (2) type of combined linear path; (3) order of scan sequences; (4) the position of the start point in each scan; (5) continuous or discontinuous scan path; (6) direction of scan path; and (7) angular arrangement of combined linear scan paths. Regarding these path parameters, ten combined linear scan patterns are presented. Numerical simulations show continuous hexagonal, scan pattern, scanning from outer to inner path, is the optimized. In addition, it is observed the position of the start point and the angular arrangement of scan paths is the most effective path parameters. Also, further experimentations show four sequences due to creat symmetric condition enhance the height of the bowl-shaped products and uniformity. Finally, the optimized hexagonal pattern was compared with the similar circular one. In the hexagonal scan path, distortion value and standard deviation rather to edge height of formed specimen is very low, and the edge height despite of decreasing length of scan path increases significantly compared to the circular scan path. As a result, four-sequence hexagonal scan pattern is proposed as the optimized perimeter scan path to produce bowl-shaped product.

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.

Histological Ex Vivo Evaluation of Peri-Incisional Thermal Effect Created by a New-Generation CO2 Superpulsed Laser

Directory of Open Access Journals (Sweden)

G. Palaia

2014-01-01

Full Text Available The purpose of this study is the evaluation of the histological effects of a new-generation superpulsed CO2 laser through an “ex vivo” study. A CO2 (λ = 10,600 nm ultra-speed laser (SmartUS20D, DEKA, Florence, Italy has been used at different parameters from 2 to 4 watt in Continuous Wave (CW and Pulsed Wave (PW, 50 Hz to obtain 30 samples from pig cadaver tongues. All the specimens have been subdivided into 6 groups (from A to F and each group consisted of 5 samples. A final specimen has been taken by scalpel and used as control group. Histological analysis has been performed using an optical microscope (Leica DM 2000 at a magnification of ×40. Results showed that histological readability was optimal in all the samples. The thermal damage has been negligible in all the groups. Furthermore, the average of thermal damage was 0,095 mm in the epithelial, while it was 0.245 mm in the connective tissue. Statistical analysis using Graphpad Prism 5 software showed no significant differences among the groups. CO2 laser demonstrated a good surgical effectiveness provoking little peripheral damage onto the cut edges and allowing a safe histological diagnosis.

a New Approach for Subway Tunnel Deformation Monitoring: High-Resolution Terrestrial Laser Scanning

Science.gov (United States)

Li, J.; Wan, Y.; Gao, X.

2012-07-01

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.

Preliminary testing of the Scanning Laser Environmental Airborne Fluorosensor

International Nuclear Information System (INIS)

Brown, C.E.; Marois, R.; Fingas, M.F.; Mullin, J.V.

2000-01-01

The installation and testing program of the Scanning Laser Environmental Airborne Fluorosensor (SLEAF) on Environment Canada's DC-3 aircraft was described and the capabilities of the new system were presented. SLEAF is a new generation of laser fluorosensor designed to provide prompt reliable detection and mapping of oil pollution in different marine and terrestrial environments. It consists of a high-power excimer laser, high-resolution range-gated intensified diode-array spectrometer, and a pair of variable speed and angular displacement scanning mirrors. SLEAF is capable of detecting narrow bands of oil that can pile up along the high tide lines of beaches and shorelines, including those that contain ice and snow. It also has the added benefit of providing real-time detection. SLEAF will be declared operational for emergency response personnel when the initial test flight program will be completed in the near future. 9 refs., 2 figs

[Results of therapy of children with amblyopia by scanning stimulating laser].

Science.gov (United States)

Chentsova, O B; Magaramova, M D; Grechanyĭ, M P

1997-01-01

A new effective method for the treatment of amblyopia was used in 113 children: stimulation with ophthalmological SLSO-208A scanning laser by two methods differing by the transmission coefficient and scanning pattern. Good results were attained, the best when laser exposure was combined with traditional therapy for amblyopia and in the patients with the central fixation. The results were assessed by the main parameters of visual functions and the stability of the effect.

A method to obtain new cross-sections transport equivalent

International Nuclear Information System (INIS)

Palmiotti, G.

1988-01-01

We present a method, that allows the calculation, by the mean of variational principle, of equivalent cross-sections in order to take into account the transport and mesh size effects on reactivity variation calculations. The method validation has been made in two and three dimensions geometries. The reactivity variations calculated in three dimensional hexagonal geometry with seven points by subassembly using two sets of equivalent cross-sections for control rods are in a very good agreement with the ones of a transport, extrapolated to zero mesh size, calculation. The difficulty encountered in obtaining a good flux distribution has lead to the utilisation of a single set of equivalent cross-sections calculated by starting from an appropriated R-Z model that allows to take into account also the axial transport effects for the control rod followers. The global results in reactivity variations are still satisfactory with a good performance for the flux distribution. The main interest of the proposed method is the possibility to simulate a full 3D transport calculation, with fine mesh size, using a 3D diffusion code, with a larger mesh size. The results obtained should be affected by uncertainties, which do not exceed ± 4% for a large LMFBR control rod worth and for very different rod configurations. This uncertainty is by far smaller than the experimental uncertainties. (author). 5 refs, 8 figs, 9 tabs

Probing defect states in polycrystalline GaN grown on Si(111) by sub-bandgap laser-excited scanning tunneling spectroscopy

Science.gov (United States)

Hsiao, F.-M.; Schnedler, M.; Portz, V.; Huang, Y.-C.; Huang, B.-C.; Shih, M.-C.; Chang, C.-W.; Tu, L.-W.; Eisele, H.; Dunin-Borkowski, R. E.; Ebert, Ph.; Chiu, Y.-P.

2017-01-01

We demonstrate the potential of sub-bandgap laser-excited cross-sectional scanning tunneling microscopy and spectroscopy to investigate the presence of defect states in semiconductors. The characterization method is illustrated on GaN layers grown on Si(111) substrates without intentional buffer layers. According to high-resolution transmission electron microscopy and cathodoluminescence spectroscopy, the GaN layers consist of nanoscale wurtzite and zincblende crystallites with varying crystal orientations and hence contain high defect state densities. In order to discriminate between band-to-band excitation and defect state excitations, we use sub-bandgap laser excitation. We probe a clear increase in the tunnel current at positive sample voltages during sub-bandgap laser illumination for the GaN layer with high defect density, but no effect is found for high quality GaN epitaxial layers. This demonstrates the excitation of free charge carriers at defect states. Thus, sub-bandgap laser-excited scanning tunneling spectroscopy is a powerful complimentary characterization tool for defect states.

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.

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.

Facial recognition and laser surface scan: a pilot study

DEFF Research Database (Denmark)

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

2009-01-01

Surface scanning of the face of a suspect is presented as a way to better match the facial features with those of a perpetrator from CCTV footage. We performed a simple pilot study where we obtained facial surface scans of volunteers and then in blind trials tried to match these scans with 2D...... photographs of the faces of the volunteers. Fifteen male volunteers were surface scanned using a Polhemus FastSCAN Cobra Handheld Laser Scanner. Three photographs were taken of each volunteer's face in full frontal, profile and from above at an angle of 45 degrees and also 45 degrees laterally. Via special...

Terrestrial Laser Scanning-Based Bridge Structural Condition Assessment : Tech Transfer Summaries

Science.gov (United States)

2016-05-01

Problem Statement : While several state departments of transportation (DOTs) have used : terrestrial laser scanning (TLS) in the project planning phase, limited : research has been conducted on employing laser scanners to detect : cracks for bridge c...

Histological staining methods preparatory to laser capture microdissection significantly affect the integrity of the cellular RNA.

Science.gov (United States)

Wang, Hongyang; Owens, James D; Shih, Joanna H; Li, Ming-Chung; Bonner, Robert F; Mushinski, J Frederic

2006-04-27

Gene expression profiling by microarray analysis of cells enriched by laser capture microdissection (LCM) faces several technical challenges. Frozen sections yield higher quality RNA than paraffin-imbedded sections, but even with frozen sections, the staining methods used for histological identification of cells of interest could still damage the mRNA in the cells. To study the contribution of staining methods to degradation of results from gene expression profiling of LCM samples, we subjected pellets of the mouse plasma cell tumor cell line TEPC 1165 to direct RNA extraction and to parallel frozen sectioning for LCM and subsequent RNA extraction. We used microarray hybridization analysis to compare gene expression profiles of RNA from cell pellets with gene expression profiles of RNA from frozen sections that had been stained with hematoxylin and eosin (H&E), Nissl Stain (NS), and for immunofluorescence (IF) as well as with the plasma cell-revealing methyl green pyronin (MGP) stain. All RNAs were amplified with two rounds of T7-based in vitro transcription and analyzed by two-color expression analysis on 10-K cDNA microarrays. The MGP-stained samples showed the least introduction of mRNA loss, followed by H&E and immunofluorescence. Nissl staining was significantly more detrimental to gene expression profiles, presumably owing to an aqueous step in which RNA may have been damaged by endogenous or exogenous RNAases. RNA damage can occur during the staining steps preparatory to laser capture microdissection, with the consequence of loss of representation of certain genes in microarray hybridization analysis. Inclusion of RNAase inhibitor in aqueous staining solutions appears to be important in protecting RNA from loss of gene transcripts.

In situ laser processing in a scanning electron microscope

Energy Technology Data Exchange (ETDEWEB)

Roberts, Nicholas A.; Magel, Gregory A.; Hartfield, Cheryl D.; Moore, Thomas M.; Fowlkes, Jason D.; Rack, Philip D. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States) and Omniprobe, Inc., an Oxford Instruments Company, 10410 Miller Rd., Dallas, Texas 75238 (United States); Omniprobe, Inc., an Oxford Instruments Company, 10410 Miller Rd., Dallas, Texas 75238 (United States); Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States) and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2012-07-15

Laser delivery probes using multimode fiber optic delivery and bulk focusing optics have been constructed and used for performing materials processing experiments within scanning electron microscope/focused ion beam instruments. Controlling the current driving a 915-nm semiconductor diode laser module enables continuous or pulsed operation down to sub-microsecond durations, and with spot sizes on the order of 50 {mu}m diameter, achieving irradiances at a sample surface exceeding 1 MW/cm{sup 2}. Localized laser heating has been used to demonstrate laser chemical vapor deposition of Pt, surface melting of silicon, enhanced purity, and resistivity via laser annealing of Au deposits formed by electron beam induced deposition, and in situ secondary electron imaging of laser induced dewetting of Au metal films on SiO{sub x}.

Fluence scan: an unexplored property of a laser beam

Czech Academy of Sciences Publication Activity Database

Chalupský, Jaromír; Burian, Tomáš; Hájková, Věra; Juha, Libor; Polcar, T.; Gaudin, J.; Nagasono, M.; Sobierajski, R.; Yabashi, M.; Krzywinski, J.

2013-01-01

Roč. 21, č. 22 (2013), s. 26363-26375 ISSN 1094-4087 R&D Projects: GA ČR(CZ) GAP108/11/1312; GA ČR GA13-28721S; GA MŠk(CZ) LG13029; GA ČR GAP208/10/2302; GA ČR GAP205/11/0571; GA MŠk EE2.3.30.0057 Grant - others:AVČR(CZ) M100101221; OP VK 4 POSTDOK(XE) CZ.1.07/2.3.00/30.0057 Institutional support: RVO:68378271 Keywords : free-electron lasers (FELs) * UV * EUV * x-ray lasers * laser beam characterization * F-scan Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.525, year: 2013

Imaging retinal degeneration in mice by combining Fourier domain optical coherence tomography and fluorescent scanning laser ophthalmoscopy

Science.gov (United States)

Hossein-Javaheri, Nima; Molday, Laurie L.; Xu, Jing; Molday, Robert S.; Sarunic, Marinko V.

2009-02-01

Visualization of the internal structures of the retina is critical for clinical diagnosis and monitoring of pathology as well as for medical research investigating the root causes of retinal degeneration. Optical Coherence Tomography (OCT) is emerging as the preferred technique for non-contact sub-surface depth-resolved imaging of the retina. The high resolution cross sectional images acquired in vivo by OCT can be compared to histology to visually delineate the retinal layers. The recent demonstration of the significant sensitivity increase obtained through use of Fourier domain (FD) detection with OCT has been used to facilitate high speed scanning for volumetric reconstruction of the retina in software. The images acquired by OCT are purely structural, relying on refractive index differences in the tissue for contrast, and do not provide information on the molecular content of the sample. We have constructed a FDOCT prototype and combined it with a fluorescent Scanning Laser Ophthalmoscope (fSLO) to permit real time alignment of the field of view on the retina. The alignment of the FDOCT system to the specimen is crucial for the registration of measurements taken throughout longitudinal studies. In addition, fluorescence detection has been integrated with the SLO to enable the en face localization of a molecular contrast signal, which is important for retinal angiography, and also for detection of autofluorescence associated with some forms of retinal degeneration, for example autofluorescence lipofuscin accumulations are associated with Stargardt's Macular Dystrophy. The integrated FD OCT/fSLO system was investigated for imaging the retina of the mice in vivo.

Atomic force microscopy of histological sections using a chemical etching method

International Nuclear Information System (INIS)

Tiribilli, B.; Bani, D.; Quercioli, F.; Ghirelli, A.; Vassalli, M.

2005-01-01

Physiology and pathology have a big deal on tissue morphology, and the intrinsic spatial resolution of an atomic force microscope (AFM) is able to observe ultrastructural details. In order to investigate cellular and subcellular structures in histological sections with the AFM, we used a new simple method for sample preparation, i.e. chemical etching of semithin sections from epoxy resin-embedded specimens: such treatment appears to melt the upper layers of the embedding resin; thus, removing the superficial roughness caused by the edge of the microtome knife and bringing into high relief the biological structures hidden in the bulk. Consecutive ultrathin sections embedded in epoxy resin were observed with a transmission electron microscope (TEM) to compare the different imaging properties on the same specimen sample. In this paper we report, as an example, our AFM and TEM images of two different tissue specimens, rat pancreas and skeletal muscle fibres, showing that most of the inner details are visible with the AFM. These results suggest that chemical etching of histological sections may be a simple, fast and cost-effective method for AFM imaging with ultrastructural resolution

Land-Based Mobile Laser Scanning Systems: a Review

Science.gov (United States)

Puente, I.; González-Jorge, H.; Arias, P.; Armesto, J.

2011-09-01

Mobile mapping has been using various photogrammetric techniques for many years. In recent years, there has been an increase in the number of mobile mapping systems using laser scanners available in the market, partially because of the improvement in GNSS/INS performance for direct georeferencing. In this article, some of the most important land-based mobile laser scanning (MLS) systems are reviewed. Firstly, the main characteristics of MLS systems vs. airborne (ALS) and terrestrial laser scanning (TLS) systems are compared. Secondly, a short overview of the mobile mapping technology is also provided so that the reader can fully grasp the complexity and operation of these devices. As we put forward in this paper, a comparison of different systems is briefly carried out regarding specifications provided by the manufacturers. Focuses on the current research are also addressed with emphasis on the practical applications of these systems. Most of them have been utilized for data collection on road infrastructures or building façades. This article shows that MLS technology is nowadays well established and proven, since the demand has grown to the point that there are several systems suppliers offering their products to satisfy this particular market.

scanning speed influence on the physical properties of laser metal

African Journals Online (AJOL)

user

2017-01-01

Jan 1, 2017 ... result of the preliminary study that produces full dense and pore free deposits. ... Keywords: Additive manufacturing, Laser metal deposition (LMD), Material efficiency, Titanium alloy. 1. ... parts. Ti6Al4V is the most commonly produced titanium alloy ... In this study, effect of laser transverse speed or scanning.

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.

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.

3D laser scanning in civil engineering - measurements of volume of earth masses

Science.gov (United States)

Pawłowicz, J. A.; Szafranko, E.; Harasymiuk, J.

2018-03-01

Considering the constant drive to improve and accelerate building processes as well as possible applications of the latest technological achievements in civil engineering practice, the author has proposed to use 3D laser scanning in the construction industry. For example, data achieved through a 3D laser scanning process will facilitate making inventories of parameters of buildings in a very short time, will enable one to check irregularly shaped masses of earth, heavy and practically impossible to calculate precisely using traditional techniques. The other part of the research, performed in the laboratory, consisted of measurements of a model mound of earth. All the measurements were made with a 3D SkanStation C10 laser scanner manufactured by Leica. The data were analyzed. The results suggest that there are great opportunities for using the laser scanning technology in civil engineering

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.

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.

ELABORATION OF THE 3D MODEL AND SURVEY OF THE POWER LINES USING DATA FROM AIRBORNE LASER SCANNING

Directory of Open Access Journals (Sweden)

Bogusława Kwoczyńska

2016-09-01

Full Text Available One of the methods of obtaining highly accurate and current spatial data about the terrain, as well as objects situated on it, is laser scanning. LIDAR (Light Detection and Ranging is among the most modern, dynamically developing technologies and reveals in surveying new capabilities that have been unachievable in a traditional way so far. The aim of the publication is to show the possibilities of using data from airborne laser scanning to perform the survey and visualization of the energy network, and also identification of hazards which the present network constitutes for the immediate environment using the TerraSolid software package. The survey was conducted for two independent sections of the power line, on the basis of two different clouds of points obtained from the airborne laser scanning. The first one had a density of 16 points/m2, while the other 22 pts/m2. The project was created in an environment of MicroStation V8i software using special overlays – TerraScan and TerraModeler of Finnish TerraSolid Company. The use of the test clouds of different densities was intended to indicate an optimal density of the cloud of points, which allows carrying out a survey and visualization of the energy network based on data derived from airborne laser scanning. The publication presents on particular examples the procedure of vectorization and visualization of the power line and detection of objects within a dangerous distance from it. The possibility of using applied LIDAR data, meeting the industry requirements, to the survey of power lines has been also confirmed.

Effects of a pulsed Nd:YAG laser on enamel and dentin

Science.gov (United States)

Myers, Terry D.

1990-06-01

Enamel and dentin samples were exposed extraorally to a pulsed neodymium yttriuma1uminumgarnet (Nd:YAG) laser. The lased samples were observed using both scanning electron microscopy and histological techniques to determine the effects of the laser. The present study has provided the following points: (1) Properly treated, enamel can be 1aser etched to a depth comparable to that achieved with phosphoric acid etching; and (2) both carious and noncarious dentin can be vaporized by the Nd:YAG laser. No cracking or chipping of any enamel or dentin sample was observed histologically or under the SEM.

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

Verification of computed tomographic estimates of cochlear implant array position: a micro-CT and histologic analysis.

Science.gov (United States)

Teymouri, Jessica; Hullar, Timothy E; Holden, Timothy A; Chole, Richard A

2011-08-01

To determine the efficacy of clinical computed tomographic (CT) imaging to verify postoperative electrode array placement in cochlear implant (CI) patients. Nine fresh cadaver heads underwent clinical CT scanning, followed by bilateral CI insertion and postoperative clinical CT scanning. Temporal bones were removed, trimmed, and scanned using micro-CT. Specimens were then dehydrated, embedded in either methyl methacrylate or LR White resin, and sectioned with a diamond wafering saw. Histology sections were examined by 3 blinded observers to determine the position of individual electrodes relative to soft tissue structures within the cochlea. Electrodes were judged to be within the scala tympani, scala vestibuli, or in an intermediate position between scalae. The position of the array could be estimated accurately from clinical CT scans in all specimens using micro-CT and histology as a criterion standard. Verification using micro-CT yielded 97% agreement, and histologic analysis revealed 95% agreement with clinical CT results. A composite, 3-dimensional image derived from a patient's preoperative and postoperative CT images using a clinical scanner accurately estimates the position of the electrode array as determined by micro-CT imaging and histologic analyses. Information obtained using the CT method provides valuable insight into numerous variables of interest to patient performance such as surgical technique, array design, and processor programming and troubleshooting.

In-vivo study and histological examination of laser reshaping of cartilage

Science.gov (United States)

Sviridov, Alexander P.; Sobol, Emil N.; Bagratashvili, Victor N.; Omelchenko, Alexander I.; Ovchinnikov, Yuriy M.; Shekhter, Anatoliy B.; Svistushkin, Valeriy M.; Shinaev, Andrei A.; Nikiforova, G.; Jones, Nicholas

1999-06-01

The results of recent study of cartilage reshaping in vivo are reported. The ear cartilage of piglets of 8-12 weeks old have been reshaped in vivo using the radiation of a holmium laser. The stability of the shape and possible side effects have been examined during four months. Histological investigation shown that the healing of irradiated are could accompany by the regeneration of ear cartilage. Finally, elastic type cartilage has been transformed into fibrous cartilage or cartilage of hyaline type.

A Combination of Stop-and-Go and Electro-Tricycle Laser Scanning Systems for Rural Cadastral Surveys

Directory of Open Access Journals (Sweden)

Liang Zhong

2016-09-01

Full Text Available Over the past decade, land-based laser scanning technologies have been actively studied and implemented, in response to the need for detailed three-dimensional (3D data about our rural and urban environment for topographic mapping, cadastral mapping, and other street-level features, which are difficult and time consuming to measure by other instruments. For rural areas in China, the complex terrain and poor planning limit the applicability of this advanced technology. To improve the efficiency of rural surveys, we present two SSW (Shoushi and SiWei laser scanning systems for rapid topographic mapping: stop-and-go and electro-tricycle laser scanning systems. The objective of this paper is to evaluate whether laser scanning data collected by the developed SSW systems meet the accuracy requirements for rural homestead mapping. We investigated the performance of the two laser scanning systems on Ma’anshan Village, a small, typical village in Hubei Province, China. To obtain full coverage of the village, we fused the stop-and-go and electro-tricycle laser scanning data. The performance of the developed SSW systems is described by the results of building contours extracted from the fused data against the established building vector map.

Fine Deformation Monitoring of Ancient Building Based on Terrestrial Laser Scanning Technologies

International Nuclear Information System (INIS)

Wei, Zhou; Huadong, Guo; Qi, Li; Tianhua, Hong

2014-01-01

Laser scanning technology has been widely used to build high-precision three dimensional models in the preservation of ancient buildings. In this paper, we take the Tower of Buddhist Incense in the Summer Palace as our research subject. Combining laser scanning technologies with close-range photogrammetry, GIS and virtual reality technologies, we acquired comprehensive and high accuracy geospatial data of the tower, and built the 3D models with an average measurement error of a single point less than 2 millimeters and a registration error of 3D data less than 5 millimeters. After data registration of the whole tower with high-precision, deformation monitoring was conducted. Having been repaired many times, the cross-sections of the tower's pillars are not in a circular shape. In order to know the dip and dip direction of each pillar exactly, ellipse fitting algorithm was used to calculate the location of the centre of every pillar. And then, the coordinates of the pillars' centre points, the major and minor axes of the ellipses, and rotation angles were calculated. The technologies and methodology used in this paper could significantly contribute towards the long-term protection of endangered cultural relics using measurements and modelling with high-levels of scientific precision

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.

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.

Approach to quantify human dermal skin aging using multiphoton laser scanning microscopy

Science.gov (United States)

Puschmann, Stefan; Rahn, Christian-Dennis; Wenck, Horst; Gallinat, Stefan; Fischer, Frank

2012-03-01

Extracellular skin structures in human skin are impaired during intrinsic and extrinsic aging. Assessment of these dermal changes is conducted by subjective clinical evaluation and histological and molecular analysis. We aimed to develop a new parameter for the noninvasive quantitative determination of dermal skin alterations utilizing the high-resolution three-dimensional multiphoton laser scanning microscopy (MPLSM) technique. To quantify structural differences between chronically sun-exposed and sun-protected human skin, the respective collagen-specific second harmonic generation and the elastin-specific autofluorescence signals were recorded in young and elderly volunteers using the MPLSM technique. After image processing, the elastin-to-collagen ratio (ELCOR) was calculated. Results show that the ELCOR parameter of volar forearm skin significantly increases with age. For elderly volunteers, the ELCOR value calculated for the chronically sun-exposed temple area is significantly augmented compared to the sun-protected upper arm area. Based on the MPLSM technology, we introduce the ELCOR parameter as a new means to quantify accurately age-associated alterations in the extracellular matrix.

Continuous-scanning laser Doppler vibrometry: Extensions to arbitrary areas, multi-frequency and 3D capture

International Nuclear Information System (INIS)

Weekes, B.; Ewins, D.; Acciavatti, F.

2014-01-01

To date, differing implementations of continuous scan laser Doppler vibrometry have been demonstrated by various academic institutions, but since the scan paths were defined using step or sine functions from function generators, the paths were typically limited to 1D line scans or 2D areas such as raster paths or Lissajous trajectories. The excitation was previously often limited to a single frequency due to the specific signal processing performed to convert the scan data into an ODS. In this paper, a configuration of continuous-scan laser Doppler vibrometry is demonstrated which permits scanning of arbitrary areas, with the benefit of allowing multi-frequency/broadband excitation. Various means of generating scan paths to inspect arbitrary areas are discussed and demonstrated. Further, full 3D vibration capture is demonstrated by the addition of a range-finding facility to the described configuration, and iteratively relocating a single scanning laser head. Here, the range-finding facility was provided by a Microsoft Kinect, an inexpensive piece of consumer electronics

The effect of green helium-neon laser on the healing of extraction wounds: histological study in rats

International Nuclear Information System (INIS)

Nicolli Filho, Walter Domingos; Picon, Luciana Christofolini; Okamoto, Tetuo; Cardenuto, Ney

1993-01-01

A histological study on healing of extraction wounds following laser irradiation, using a green He-Ne laser, was carried out in rats. The results suggest that this kind of treatment has no significant beneficial effect on bony wound healing. Proliferation of fibroblasts and formation of trabecular osteoid were found to be not more pro eminent within the irradiated group. (author)

Histological staining methods preparatory to laser capture microdissection significantly affect the integrity of the cellular RNA

Directory of Open Access Journals (Sweden)

Li Ming-Chung

2006-04-01

Full Text Available Abstract Background Gene expression profiling by microarray analysis of cells enriched by laser capture microdissection (LCM faces several technical challenges. Frozen sections yield higher quality RNA than paraffin-imbedded sections, but even with frozen sections, the staining methods used for histological identification of cells of interest could still damage the mRNA in the cells. To study the contribution of staining methods to degradation of results from gene expression profiling of LCM samples, we subjected pellets of the mouse plasma cell tumor cell line TEPC 1165 to direct RNA extraction and to parallel frozen sectioning for LCM and subsequent RNA extraction. We used microarray hybridization analysis to compare gene expression profiles of RNA from cell pellets with gene expression profiles of RNA from frozen sections that had been stained with hematoxylin and eosin (H&E, Nissl Stain (NS, and for immunofluorescence (IF as well as with the plasma cell-revealing methyl green pyronin (MGP stain. All RNAs were amplified with two rounds of T7-based in vitro transcription and analyzed by two-color expression analysis on 10-K cDNA microarrays. Results The MGP-stained samples showed the least introduction of mRNA loss, followed by H&E and immunofluorescence. Nissl staining was significantly more detrimental to gene expression profiles, presumably owing to an aqueous step in which RNA may have been damaged by endogenous or exogenous RNAases. Conclusion RNA damage can occur during the staining steps preparatory to laser capture microdissection, with the consequence of loss of representation of certain genes in microarray hybridization analysis. Inclusion of RNAase inhibitor in aqueous staining solutions appears to be important in protecting RNA from loss of gene transcripts.

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.

Evaluation of retinal nerve fiber layer thickness parameters in myopic population using scanning laser polarimetry (GDxVCC).

Science.gov (United States)

Dada, Tanuj; Aggarwal, A; Bali, S J; Sharma, A; Shah, B M; Angmo, D; Panda, A

2013-01-01

Myopia presents a significant challenge to the ophthalmologist as myopic discs are often large, tilted, with deep cups and have a thinner neuroretinal rim all of which may mimic glaucomatous optic nerve head changes causing an error in diagnosis. To evaluate the retinal fiber layer (RNFL) thickness in low, moderate and high myopia using scanning laser polarimetry with variable corneal compensation (GDxVCC). One hundred eyes of 100 emmetropes, 30 eyes of low myopes (0 to - 4 D spherical equivalent(SE), 45 eyes with moderate myopia (- 4 to - 8D SE), and 30 eyes with high myopia (- 8 to - 15D SE) were subjected to retinal nerve fiber layer assessment using the scanning laser polarimetry (GDxVCC) in all subjects using the standard protocol. Subjects with IOP > 21 mm Hg, optic nerve head or visual field changes suggestive of glaucoma were excluded from the study. The major outcome parameters were temporal-superior-nasal-inferiortemporal (TSNIT) average, the superior and inferior average and the nerve fibre indicator (NFI). The TSNIT average (p = 0.009), superior (p = 0.001) and inferior average (p = 0.008) were significantly lower; the NFI was higher (P less than 0.001) in moderate myopes as compared to that in emmetropes. In high myopia the RNFL showed supranormal values; the TSNIT average, superior and inferior average was significantly higher(p less than 0.001) as compared to that in emmetropes. The RNFL measurements on scanning laser polarimetry are affected by the myopic refractive error. Moderate myopes show a significant thinning of the RNFL. In high myopia due to peripapillary chorioretinal atrophy and contribution of scleral birefringence, the RNFL values are abnormally high. These findings need to be taken into account while assessing and monitoring glaucoma damage in moderate to high myopes on GDxVCC. © NEPjOPH.

In vitro histological evaluation of the surgical margins made by different laser wavelengths in tongue tissues

Science.gov (United States)

Azevedo, Ana-Salvaterra; Ferreira, Fernando; Delgado, Maria-Leonor; Garcês, Fernanda; Carreira, Sofia; Martins, Marco; Suarez-Quintanilla, Juan

2016-01-01

Background Lasers have become standard tools for the surgical treatment of oral lesions. The purpose of this study is to determine the surgical margins and histologically evaluate the tissue thermal effects induced by different types of surgical instruments. Material and Methods Cuts were made in pork tongues’ mucosa with different lasers (Er:YAG at 2W with and without air / water spray and at 4W with and without air / water spray; CO2 at 3.5W and 7W in pulsed mode and at 7W in continuous mode; the diode laser at 3.5W and boost 3.5W in pulsed mode; Nd:YAG at 6W, 40Hz and electroscalpel at 5W and conventional scalpel as control. Macroscopic and microscopic morphological changes were evaluated. Results The results of this study showed that the surgical instruments that caused greater tissue damage extension were: the Nd:YAG laser (670.68μm), the diode 3.5W and boost PW (626.82μm), the CO2 7W CW (571.18μm), the CO2 at 7W PW (485.45μm), the diode 3.5W PW (456.15μm), the electroscalpel (409.57μm) and lastly the CO2 laser 3.5W PW (306.19μm) and Er:YAG (74.66μm) laser, regardless of power, mode or air / water spray used. An association between the Tissue Damage Extension and the Degree of Carbonization (r = 0.789; P = 0.01), and an association between the Tissue Damage Extension and Regularity of the Incision were found (r = -, 299; P = 0.01). Conclusions The results of this study suggest that lasers can be used in soft tissues biopsies of the oral cavity, enabling a correct histopathological analysis, as long as the biological effects of each laser type are considered. The Er:YAG laser revealed its potential for biopsies of the oral mucosa ensuring a successful histological evaluation and the CO2 laser at 3,5W in pulsed mode presented itself as the best choice for surgeries with hemostasis. Key words:CO2 laser, diode laser, Er:YAG laser, laser surgery, Nd:YAG laser, oral mucosa, thermal effect. PMID:27703606

Inspection of float glass using a novel retroreflective laser scanning system

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Holmes, Jonathan D.

1997-07-01

Since 1988, Image Automation has marketed a float glass inspection system using a novel retro-reflective laser scanning system. The (patented) instrument scans a laser beam by use of a polygon through the glass onto a retro-reflective screen, and collects the retro-reflected light off the polygon, such that a stationary image of the moving spot on the screen is produced. The spot image is then analyzed for optical effects introduced by defects within the glass, which typically distort and attenuate the scanned laser beam, by use of suitable detectors. The inspection system processing provides output of defect size, shape and severity, to the factory network for use in rejection or sorting of glass plates to the end customer. This paper briefly describes the principles of operation, the system architecture, and limitations to sensitivity and measurement repeatability. New instruments based on the retro-reflective scanning method have recently been developed. The principles and implementation are described. They include: (1) Simultaneous detection of defects within the glass and defects in a mirror coating on the glass surface using polarized light. (2) A novel distortion detector for very dark glass. (3) Measurement of optical quality (flatness/refractive homogeneity) of the glass using a position sensitive detector.

Measurement Axis Searching Model for Terrestrial Laser Scans Registration

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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.

Structured-Light Based 3d Laser Scanning of Semi-Submerged Structures

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van der Lucht, J.; Bleier, M.; Leutert, F.; Schilling, K.; Nüchter, A.

2018-05-01

In this work we look at 3D acquisition of semi-submerged structures with a triangulation based underwater laser scanning system. The motivation is that we want to simultaneously capture data above and below water to create a consistent model without any gaps. The employed structured light scanner consist of a machine vision camera and a green line laser. In order to reconstruct precise surface models of the object it is necessary to model and correct for the refraction of the laser line and camera rays at the water-air boundary. We derive a geometric model for the refraction at the air-water interface and propose a method for correcting the scans. Furthermore, we show how the water surface is directly estimated from sensor data. The approach is verified using scans captured with an industrial manipulator to achieve reproducible scanner trajectories with different incident angles. We show that the proposed method is effective for refractive correction and that it can be applied directly to the raw sensor data without requiring any external markers or targets.

STRUCTURED-LIGHT BASED 3D LASER SCANNING OF SEMI-SUBMERGED STRUCTURES

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J. van der Lucht

2018-05-01

Full Text Available In this work we look at 3D acquisition of semi-submerged structures with a triangulation based underwater laser scanning system. The motivation is that we want to simultaneously capture data above and below water to create a consistent model without any gaps. The employed structured light scanner consist of a machine vision camera and a green line laser. In order to reconstruct precise surface models of the object it is necessary to model and correct for the refraction of the laser line and camera rays at the water-air boundary. We derive a geometric model for the refraction at the air-water interface and propose a method for correcting the scans. Furthermore, we show how the water surface is directly estimated from sensor data. The approach is verified using scans captured with an industrial manipulator to achieve reproducible scanner trajectories with different incident angles. We show that the proposed method is effective for refractive correction and that it can be applied directly to the raw sensor data without requiring any external markers or targets.

Automatic concrete cracks detection and mapping of terrestrial laser scan data

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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.

Deriving structural forest parameters using airborne laser scanning

International Nuclear Information System (INIS)

Morsdorf, F.

2011-01-01

Airborne laser scanning is a relatively young and precise technology to directly measure surface elevations. With today's high scanning rates, dense 3-D pointclouds of coordinate triplets (xyz) can be provided, in which many structural aspects of the vegetation are contained. The challenge now is to transform this data, as far as possible automatically, into manageable information relevant to the user. In this paper we present two such methods: the first extracts automatically the geometry of individual trees, with a recognition rate of over 70% and a systematic underestimation of tree height of only 0.6 metres. The second method derives a pixel map of the canopy density from the pointcloud, in which the spatial patterns of vegetation cover are represented. These patterns are relevant for habitat analysis and ecosystem studies. The values derived by this method correlate well with field measurements, giving a measure of certainty (R 2 ) of 0.8. The greatest advantage of airborne laser scanning is that it provides spatially extensive, direct measurements of vegetation structure which show none of the extrapolation errors of spot measurements. A large challenge remains in integrating these new products into the user's processing chains and workflows, be it in the realm of forestry or in that of ecosystem research. (author) [de

Improving Completeness of Geometric Models from Terrestrial Laser Scanning Data

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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.

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

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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.

Capturing and modelling high-complex alluvial topography with UAS-borne laser scanning

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Mandlburger, Gottfried; Wieser, Martin; Pfennigbauer, Martin

2015-04-01

Due to fluvial activity alluvial forests are zones of highest complexity and relief energy. Alluvial forests are dominated by new and pristine channels in consequence of current and historic flood events. Apart from topographic features, the vegetation structure is typically very complex featuring, both, dense under story as well as high trees. Furthermore, deadwood and debris carried from upstream during periods of high discharge within the river channel are deposited in these areas. Therefore, precise modelling of the micro relief of alluvial forests using standard tools like Airborne Laser Scanning (ALS) is hardly feasible. Terrestrial Laser Scanning (TLS), in turn, is very time consuming for capturing larger areas as many scan positions are necessary for obtaining complete coverage due to view occlusions in the forest. In the recent past, the technological development of Unmanned Arial Systems (UAS) has reached a level that light-weight survey-grade laser scanners can be operated from these platforms. For capturing alluvial topography this could bridge the gap between ALS and TLS in terms of providing a very detailed description of the topography and the vegetation structure due to the achievable very high point density of >100 points per m2. In our contribution we demonstrate the feasibility to apply UAS-borne laser scanning for capturing and modelling the complex topography of the study area Neubacher Au, an alluvial forest at the pre-alpine River Pielach (Lower Austria). The area was captured with Riegl's VUX-1 compact time-of-flight laser scanner mounted on a RiCopter (X-8 array octocopter). The scanner features an effective scan rate of 500 kHz and was flown in 50-100 m above ground. At this flying height the laser footprint is 25-50 mm allowing mapping of very small surface details. Furthermore, online waveform processing of the backscattered laser energy enables the retrieval of multiple targets for single laser shots resulting in a dense point cloud of

Evolution of laser skin resurfacing: from scanning to fractional technology.

Science.gov (United States)

Aslam, Arif; Alster, Tina S

2014-11-01

Laser skin resurfacing was popularized for photoaged and scarred skin 2 decades ago. Since then, several technologic advancements have led to a new generation of delivery systems that produce excellent clinical outcomes with reduced treatment risks and faster recovery times. To review the evolution of laser skin resurfacing from pulsed and scanned infrared laser technology to the latest techniques of nonablative and ablative fractional photothermolysis. All published literature regarding laser skin resurfacing was analyzed and collated. A comprehensive review of laser skin resurfacing was outlined and future developments in the field of fractionated laser skin treatment were introduced. Laser skin resurfacing has evolved such that excellent clinical outcomes in photodamaged and scarred skin are achieved with rapid wound healing. As newer devices are developed, the applications of this technology will have a dramatic effect on the delivery of medical and aesthetic dermatology.

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

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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.

Single scan femtosecond laser transverse writing of depressed cladding waveguides enabled by three-dimensional focal field engineering.

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Zhang, Qian; Yang, Dong; Qi, Jia; Cheng, Ya; Gong, Qihuang; Li, Yan

2017-06-12

We report single scan transverse writing of depressed cladding waveguides inside ZBLAN glass with the longitudinally oriented annular ring-shaped focal intensity distribution of the femtosecond laser. The entire region of depressed cladding at the cross section, where a negative change of refraction index is induced, can be modified simultaneously with the ring-shaped focal intensity profile. The fabricated waveguides exhibit good single guided mode.

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

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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.

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.

ANALYSIS OF TERRESTRIAL LASER SCANNING AND PHOTOGRAMMETRY DATA FOR DOCUMENTATION OF HISTORICAL ARTIFACTS

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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.

A walk by the river: three-dimensional reconstruction of surface sedimentology and topography using wearable laser scanning

Science.gov (United States)

Williams, R.; Lamy, M. L.; Stott, E.; Maniatis, G.

2017-12-01

In the last two decades, quantification of fluvial topography has been transformed by a number of geomatics technologies that have enabled the acquisition of data with unprecedented spatial resolution. Hyperscale surveys with spatial extents of <1 km2 have been widely demonstrated, by means of Terrestrial Laser Scanning (TLS) and Structure-from-Motion (SfM) photogrammetry. Recent advances in the development and integration of GNSS, IMU, lightweight laser scanning and SLAM technologies are now resulting in the emergence of wearable, mobile laser scanning systems that have the potential to increase data acquisition and processing rates by 1-2 orders of magnitude compared to TLS/SfM, and thus challenge the recent dominance of these two geomatics technologies. In this study we describe the methods and results of a comparison between a wearable laser scanning survey, using a Leica Pegasus Backpack, and a multi-station static TLS survey, using a Riegl VZ-1000 scanner. The evaluation is undertaken on a 600 m long reach of the braided River Feshie, Scotland, using data acquired in June 2017. Comparison between the DEMs produced from static and mobile laser scanning, across non-vegetated areas, revealed a Mean Error (ME) of -0.002 m and a Standard Deviation Error (SDE) of 0.109 m. Comparison to 100 independent check point resulted in a similar ME and SDE for static (ME = 0.061m; SDE = 0.030 m) and mobile (ME = 0.044 m; SDE = 0.029 m) laser scanning. Empirical relationships between sub-metre topographic variability and median sediment grain size (10-100 mm), across 14 grid-by-number samples, were similar and demonstrate that surface roughness from wearable laser scanning can be used to derive reach-scale maps of median grain size. These results demonstrate that wearable laser scanning generates hyperscale topographic models that are comparable in quality to more time-consuming multi-station TLS setups. Wearable laser scanning is likely to be commonly adopted for fluvial

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

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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.

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.

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.

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.

INITIAL TESTS AND ACCURACY ASSESMENT OF A COMPACT MOBILE LASER SCANNING SYSTEM

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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.

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.

In-vivo imaging of retinal nerve fiber layer vasculature: imaging – histology comparison

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Libby Richard T

2009-08-01

Full Text Available Abstract Background Although it has been suggested that alterations of nerve fiber layer vasculature may be involved in the etiology of eye diseases, including glaucoma, it has not been possible to examine this vasculature in-vivo. This report describes a novel imaging method, fluorescence adaptive optics (FAO scanning laser ophthalmoscopy (SLO, that makes possible for the first time in-vivo imaging of this vasculature in the living macaque, comparing in-vivo and ex-vivo imaging of this vascular bed. Methods We injected sodium fluorescein intravenously in two macaque monkeys while imaging the retina with an FAO-SLO. An argon laser provided the 488 nm excitation source for fluorescence imaging. Reflectance images, obtained simultaneously with near infrared light, permitted precise surface registration of individual frames of the fluorescence imaging. In-vivo imaging was then compared to ex-vivo confocal microscopy of the same tissue. Results Superficial focus (innermost retina at all depths within the NFL revealed a vasculature with extremely long capillaries, thin walls, little variation in caliber and parallel-linked structure oriented parallel to the NFL axons, typical of the radial peripapillary capillaries (RPCs. However, at a deeper focus beneath the NFL, (toward outer retina the polygonal pattern typical of the ganglion cell layer (inner and outer retinal vasculature was seen. These distinguishing patterns were also seen on histological examination of the same retinas. Furthermore, the thickness of the RPC beds and the caliber of individual RPCs determined by imaging closely matched that measured in histological sections. Conclusion This robust method demonstrates in-vivo, high-resolution, confocal imaging of the vasculature through the full thickness of the NFL in the living macaque, in precise agreement with histology. FAO provides a new tool to examine possible primary or secondary role of the nerve fiber layer vasculature in retinal

Surface modification of ceramic and metallic alloy substrates by laser raster-scanning

Science.gov (United States)

Ramos Grez, Jorge Andres

This work describes the feasibility of continuous wave laser-raster scan-processing under controlled atmospheric conditions as employed in three distinct surface modification processes: (a) surface roughness reduction of indirect-Selective Laser Sintered 420 martensitic stainless steel-40 wt. % bronze infiltrated surfaces; (b) Si-Cr-Hf-C coating consolidation over 3D carbon-carbon composites cylinders; (c) dendritic solidification structures of Mar-M 247 confined powder precursor grown from polycrystalline Alloy 718 substrates. A heat transfer model was developed to illustrate that the aspect ratio of the laser scanned pattern and the density of scanning lines play a significant role in determining peak surface temperature, heating and cooling rates and melt resident times. Comprehensive characterization of the surface of the processed specimens was performed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), optical metallography, X-ray diffraction (XRD), and, in certain cases, tactile profilometry. In Process (a), it was observed that a 24% to 37% roughness Ra reduction could be accomplished from the as-received value of 2.50+/-0.10 microns for laser energy densities ranging from 350 to 500 J/cm2. In Process (b), complete reactive wetting of carbon-carbon composite cylinders surface was achieved by laser melting a Si-Cr-Hf-C slurry. Coatings showed good thermal stability at 1000°C in argon, and, when tested in air, a percent weight reduction rate of -6.5 wt.%/hr was achieved. A soda-glass overcoat applied over the coated specimens by conventional means revealed a percent weight reduction rate between -1.4 to -2.2 wt.%/hr. Finally, in Process (c), microstructure of the Mar-M 247 single layer deposits, 1 mm in height, grown on Alloy 718 polycrystalline sheets, resulted in a sound metallurgical bond, low porosity, and uniform thickness. Polycrystalline dendrites grew preferentially along the [001] direction from the substrate up to 400

UTILIZATION OF 940 NM WAVELENGTH DIODE LASERS AND THE MORPHO‐HISTOLOGICAL MODIFICATIONS IN PERIODONTAL TISSUES

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I. LUCHIAN

2013-07-01

Full Text Available Introduction: Non‐conventional techniques represent a more and more frequently employed alternative in medi‐ cine, firstly due to their minimally invasive character. Laser technologies represent forward‐looking methods to which numerous stomatologists resort, mainly because of their multiple applications in periodontology.The scope of the study was to identify the possible morpho‐histological differences on microscopic preparati‐ ons obtained by the two ‐ conventional and non‐conventi‐ onal – laser‐assisted techniques.Materials and method: Gingivectomies have been rea‐ lized on a mandible of freshly sacrificed pig, by the classi‐ cal surgical technique, 10 tissue samples of comparable size being taken over. On the same mandible, in the opposite quadrant, gingivectomies were realized by means of a diode‐type laser with a wavelength of 940 nm, followed by taking over of other 10 tissue samples. All specimens were conserved in a fixing solution and histological cups were obtained for subsequent analysis in the laboratory of pathological anatomy.Results and discussion: Histological evaluation evi‐ denced no significant morpho‐histological differences between the two techniques applied. The clinical advanta‐ ges of the photo‐mecanical interactions provided by laser‐assisted periodontal surgery include mainly reduc‐ tion of bleeding, absence of oedema, a higher confort for the patient (who suffers less pain and a much more rapid healing (by a faster tissular repair.Conclusions: Laser‐assisted technologies may be the‐ refore viewed as extremely useful alternatives in the new periodontal therapies, which recommends their applica‐ tion in periodontal surgery for at least three reasons: they are minimally invasive, they induce minor morpho‐histo‐ logical modifications and the technique of their application is simple to learn.

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.

D Model of AL Zubarah Fortress in Qatar - Terrestrial Laser Scanning VS. Dense Image Matching

Science.gov (United States)

Kersten, T.; Mechelke, K.; Maziull, L.

2015-02-01

In September 2011 the fortress Al Zubarah, built in 1938 as a typical Arabic fortress and restored in 1987 as a museum, was recorded by the HafenCity University Hamburg using terrestrial laser scanning with the IMAGER 5006h and digital photogrammetry for the Qatar Museum Authority within the framework of the Qatar Islamic Archaeology and Heritage Project. One goal of the object recording was to provide detailed 2D/3D documentation of the fortress. This was used to complete specific detailed restoration work in the recent years. From the registered laser scanning point clouds several cuttings and 2D plans were generated as well as a 3D surface model by triangle meshing. Additionally, point clouds and surface models were automatically generated from digital imagery from a Nikon D70 using the open-source software Bundler/PMVS2, free software VisualSFM, Autodesk Web Service 123D Catch beta, and low-cost software Agisoft PhotoScan. These outputs were compared with the results from terrestrial laser scanning. The point clouds and surface models derived from imagery could not achieve the same quality of geometrical accuracy as laser scanning (i.e. 1-2 cm).

Fabrication of rectangular cross-sectional microchannels on PMMA with a CO2 laser and underwater fabricated copper mask

Science.gov (United States)

Prakash, Shashi; Kumar, Subrata

2017-09-01

CO2 lasers are commonly used for fabricating polymer based microfluidic devices. Despite several key advantages like low cost, time effectiveness, easy to operate and no requirement of clean room facility, CO2 lasers suffer from few disadvantages like thermal bulging, improper dimensional control, difficulty to produce microchannels of other than Gaussian cross sectional shapes and inclined surface walls. Many microfluidic devices require square or rectangular cross-sections which are difficult to produce using normal CO2 laser procedures. In this work, a thin copper sheet of 40 μm was used as a mask above the PMMA (Polymethyl-methacrylate) substrate while fabricating the microchannels utilizing the raster scanning feature of the CO2 lasers. Microchannels with different width dimensions were fabricated utilizing a CO2 laser in with mask and without-mask conditions. A comparison of both the fabricating process has been made. It was found that microchannels with U shape cross section and rectangular cross-section can efficiently be produced using the with mask technique. In addition to this, this technique can provide perfect dimensional control and better surface quality of the microchannel walls. Such a microchannel fabrication process do not require any post-processing. The fabrication of mask using a nanosecond fiber laser has been discussed in details. An underwater laser fabrication method was adopted to overcome heat related defects in mask preparation. Overall, the technique was found to be easy to adopt and significant improvements were observed in microchannel fabrication.

Slice-to-Volume Nonrigid Registration of Histological Sections to MR Images of the Human Brain

Science.gov (United States)

Osechinskiy, Sergey; Kruggel, Frithjof

2011-01-01

Registration of histological images to three-dimensional imaging modalities is an important step in quantitative analysis of brain structure, in architectonic mapping of the brain, and in investigation of the pathology of a brain disease. Reconstruction of histology volume from serial sections is a well-established procedure, but it does not address registration of individual slices from sparse sections, which is the aim of the slice-to-volume approach. This study presents a flexible framework for intensity-based slice-to-volume nonrigid registration algorithms with a geometric transformation deformation field parametrized by various classes of spline functions: thin-plate splines (TPS), Gaussian elastic body splines (GEBS), or cubic B-splines. Algorithms are applied to cross-modality registration of histological and magnetic resonance images of the human brain. Registration performance is evaluated across a range of optimization algorithms and intensity-based cost functions. For a particular case of histological data, best results are obtained with a TPS three-dimensional (3D) warp, a new unconstrained optimization algorithm (NEWUOA), and a correlation-coefficient-based cost function. PMID:22567290

Slice-to-Volume Nonrigid Registration of Histological Sections to MR Images of the Human Brain

Directory of Open Access Journals (Sweden)

Sergey Osechinskiy

2011-01-01

Full Text Available Registration of histological images to three-dimensional imaging modalities is an important step in quantitative analysis of brain structure, in architectonic mapping of the brain, and in investigation of the pathology of a brain disease. Reconstruction of histology volume from serial sections is a well-established procedure, but it does not address registration of individual slices from sparse sections, which is the aim of the slice-to-volume approach. This study presents a flexible framework for intensity-based slice-to-volume nonrigid registration algorithms with a geometric transformation deformation field parametrized by various classes of spline functions: thin-plate splines (TPS, Gaussian elastic body splines (GEBS, or cubic B-splines. Algorithms are applied to cross-modality registration of histological and magnetic resonance images of the human brain. Registration performance is evaluated across a range of optimization algorithms and intensity-based cost functions. For a particular case of histological data, best results are obtained with a TPS three-dimensional (3D warp, a new unconstrained optimization algorithm (NEWUOA, and a correlation-coefficient-based cost function.

Nitinol laser cutting: microstructure and functional properties of femtosecond and continuous wave laser processing

Science.gov (United States)

Biffi, C. A.; Tuissi, A.

2017-03-01

Thermal processing can affect the properties of smart materials, and the correct selection of the best manufacturing technology is fundamental for producing high tech smart devices, containing embedded functional properties. In this work cutting of thin superelastic Nitinol plates using a femtosecond (fs) and continuous wave (CW) laser was studied. Diamond shaped elements were cut to characterize the kerf qualitative features; microstructural analysis of the cross sections allowed identification of thermal damage characteristics introduced into the material during the laser processes. A thermally undamaged microstructure was observed for fs laser cutting, while CW was seen to be characterized by a large heat-affected zone. Functional properties were investigated by differential scanning calorimetry and tensile testing of laser cut microelements and of the reference material. It was seen that the martensitic transformation behavior of Nitinol is not affected by fs regime, while cw cutting provokes an effect equivalent to a high temperature thermal treatment in the material surrounding the cutting kerf, degradating the material properties. Finally, tensile testing indicated that superelastic performances were guaranteed by fs regime, while strong reduction of the recoverable strain was detected in the CW processed sample.

Elemental mapping and quantitative analysis of Cu, Zn, and Fe in rat brain sections by laser ablation ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Jackson, Brian [Dartmouth College, Departments of Earth Sciences and Chemistry, Hanover, NH (United States); Harper, Steve [University of Georgia, Savannah River Ecology Laboratory, Aiken, SC (United States); Smith, Laura; Flinn, Jane [George Mason University, Department of Psychology, Fairfax, VA (United States)

2006-02-15

This report details the application of laser ablation quadrupole ICP-MS for the (multi)elemental mapping of 100-{mu}m-thick sections of rat brain. The laser spot size used was 60 {mu}m, and the laser scan speed was 120 {mu}m s{sup -1}. The analysis was relatively rapid, allowing mapping of a whole brain thin section ({approx}1 cm{sup 2}) in about 2 h. Furthermore, the method was amenable to multi-element data collection including the physiologically important elements P and S and afforded sub {mu}g g{sup -1} detection limits for the important trace elements Cu and Zn. Calibrations were performed with pressed pellets of biological certified reference materials, and the elemental distributions and concentrations of Cu, Zn, and Fe were determined in whole rat brain sections. The distributions and concentration ranges for these elements were consistent with previous studies and demonstrate the utility of this technique for rapid mapping of brain thin sections. (orig.)

Function analysis of working integrated circuit with scanning laser microscope. Laser kenbikyo ni yoru IC no dosa kansatsu

Energy Technology Data Exchange (ETDEWEB)

Ode, T. (Lasertec Corp., Kanagawa (Japan))

1992-10-20

By scanning a laser light, the reaction of a specimen against the light is detected in some means. The optical effect can be visualized by displaying that on the CRT or the like in synchronism with the scanning. Among these, an image formed and visualized by internal photoelectric effect by light is called OBIC image, and chiefly used for evaluating and analyzing semiconductor devices. Observing this OBIC image by a high speed scanning laser microscope has been spotlighted these days as an effective means for observing the state of p-n junction of an IC in operation. This paper descries the principle, the observing method, the detecting circuit, etc. of the semiconductor observing method using a laser microscope. Further, actual examples of detecting defects of an IC by means of OBIC image are shown. As for the problem, since leak parts are displayed as negative contrast in the OBIC image to affect finding work of leak part, the necessity of improvement is pointed out. 39 refs., 11 figs.

Integrated two-section discrete mode laser

NARCIS (Netherlands)

Anandarajah, P.M.; Latkowski, S.; Browning, C.; Zhou, R.; O'Carroll, J.; Phelan, R.; Kelly, B.; O'Gorman, J.; Barry, L.P.

2012-01-01

The authors present the design and characterization of a novel integrated two-section discrete mode index patterned diode laser source. The two slotted regions etched into the laser ridge waveguide are formed in the same fabrication step as the ridge, thus avoiding the requirement for complex

Effect of Laser Power and Scan Speed on Melt Pool Characteristics of Commercially Pure Titanium (CP-Ti)

Science.gov (United States)

Kusuma, Chandrakanth; Ahmed, Sazzad H.; Mian, Ahsan; Srinivasan, Raghavan

2017-07-01

Selective laser melting (SLM) is an additive manufacturing technique that creates complex parts by selectively melting metal powder layer-by-layer using a laser. In SLM, the process parameters decide the quality of the fabricated component. In this study, single beads of commercially pure titanium (CP-Ti) were melted on a substrate of the same material using an in-house built SLM machine. Multiple combinations of laser power and scan speed were used for single bead fabrication, while the laser beam diameter and powder layer thickness were kept constant. This experimental study investigated the influence of laser power, scan speed, and laser energy density on the melt pool formation, surface morphology, geometry (width and height), and hardness of solidified beads. In addition, the observed unfavorable effect such as inconsistency in melt pool width formation is discussed. The results show that the quality, geometry, and hardness of solidified melt pool are significantly affected by laser power, scanning speed, and laser energy density.

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.

Optomechatronics Design and Control for Confocal Laser Scanning Microscopy

NARCIS (Netherlands)

Yoo, H.W.

2015-01-01

Confocal laser scanning microscopy (CLSM) is considered as one of the major advancements in microscopy in the last century and is widely accepted as a 3D fluorescence imaging tool for biological studies. For the emerging biological questions CLSM requires fast imaging to detect rapid biological

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.

Histological study on the effect of He-Ne laser on the compound eyes of the locust Schistocerca Gregaria Forsk (Orthoptera-Acridiidae)

International Nuclear Information System (INIS)

Abd El-Meguid, A.; El-Gundi, A.M.; Osiris, W.G.; El-Kes, N.

1996-01-01

In the present study, the effect of the He-Ne laser beam at different exposure periods (10,30 and 60 minutes) on the histological structure of the compound eyes of Schistocerca Gregaria Forsk is investigated. This study shows that various remarkable changes occurred in the histological structure of the right exposed eye (R) as in the left eye (L) (unexposed eye of the same insect), which may be due to a change in the micro-environment of the compound eyes, affected by the laser beam, furthermore, damage in the photoreceptors of the compound eyes of the insect was observed. 23 figs

Experimental validation of a newly designed 6 degrees of freedom scanning laser head: Application to three-dimensional beam structure

International Nuclear Information System (INIS)

Di Maio, D.; Copertaro, E.

2013-01-01

A new scanning laser head is designed to use single Laser Doppler Vibrometer (LDV) for performing measurements up to 6 degrees of freedom (DOF) at a target. The scanning head is supported by a rotating hollow shaft, which allows the laser beam to travel up to the scanning head from an opposite direction where an LDV is set up. The scanning head is made of a set of two mirrors, which deflects the laser beam with an angle so that the rotation of the scanning head produces a conical scan. When measurements are performed at the focal point of the conical scan then three translational vibration components can be measured, otherwise the very small circle scan, before and after the focal point, can measure up to 6 degrees of freedom, including three translations and three rotations. This paper presents the 6DOF scanning head and the measurements of 3D operational deflection shapes of a test structure

Acetylcholinesterase and Nissl staining in the same histological section.

Science.gov (United States)

Shipley, M T; Ennis, M; Behbehani, M M

1989-12-18

Acetylcholinesterase (AChE) enzyme histochemistry and Nissl staining are commonly utilized in neural architectonic studies. However, the opaque reaction deposit produced by the most commonly used AChE histochemical methods is not compatible with satisfactory Nissl staining. As a result, precise correlation of AChE and Nissl staining necessitates time-consuming comparisons of adjacent sections which may have differential shrinkage. Here, we have modified the Koelle-Friedenwald histochemical reaction for AChE by omitting the final intensification steps. The modified reaction yields a non-opaque reaction product that is selectively visualized by darkfield illumination. This non-intensified darkfield AChE (NIDA) reaction allows clear visualization of Nissl staining in the same histological section. This combined AChE-Nissl method greatly facilitates detailed correlation of enzyme and cytoarchitectonic organization.

Semi-Automatic Registration of Airborne and Terrestrial Laser Scanning Data Using Building Corner Matching with Boundaries as Reliability Check

Directory of Open Access Journals (Sweden)

Liang Cheng

2013-11-01

Full Text Available Data registration is a prerequisite for the integration of multi-platform laser scanning in various applications. A new approach is proposed for the semi-automatic registration of airborne and terrestrial laser scanning data with buildings without eaves. Firstly, an automatic calculation procedure for thresholds in density of projected points (DoPP method is introduced to extract boundary segments from terrestrial laser scanning data. A new algorithm, using a self-extending procedure, is developed to recover the extracted boundary segments, which then intersect to form the corners of buildings. The building corners extracted from airborne and terrestrial laser scanning are reliably matched through an automatic iterative process in which boundaries from two datasets are compared for the reliability check. The experimental results illustrate that the proposed approach provides both high reliability and high geometric accuracy (average error of 0.44 m/0.15 m in horizontal/vertical direction for corresponding building corners for the final registration of airborne laser scanning (ALS and tripod mounted terrestrial laser scanning (TLS data.

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 countrywid...

The equivalent width as a figure of merit for XPS narrow scans

International Nuclear Information System (INIS)

Singh, Bhupinder; Velázquez, Daniel; Terry, Jeff; Linford, Matthew R.

2014-01-01

Highlights: • We introduce a new figure of merit for XPS narrow scans: the equivalent width (EW XPS ). • EW XPS is less subjective and involves lesser user bias than traditional peak fitting. • EW XPS is responsive to changes in chemical states of materials. • EW XPS could be used for quality control and comparing spectra from similar samples. • EW XPS has the potential to be part of an expert software system for machine interpretation of spectra. - Abstract: X-ray Photoelectron Spectroscopy (XPS) is a widely used surface analytical tool that provides information about the near surface regions of materials. And while indispensable for XPS data analysis, peak fitting of narrow scans is often a fairly subjective exercise. Herein we introduce the equivalent width (EW) as an additional and less subjective figure of merit for XPS narrow scans. We believe that this parameter will prove particularly useful for analyzing series of similar or nominally identical spectra, perhaps as a component of an expert software system for the machine interpretation of spectra. It also appears to be useful, shedding light on the chemical state of materials, when additional information about a sample is known. The EW XPS is simply defined as the area of a narrow scan divided by the height of the maximum of its peak envelope. To limit any ambiguity in EW XPS for a series of spectra, we may also list the peak position of the maximum of the envelope (PE max ). The potential usefulness and limitations of the EW XPS and PE max parameters are demonstrated by their application to the narrow scans of: (i) four sets of ozone-treated carbon nanotubes (EW XPS ∼ 2.11–2.16 eV for a Shirley background, and up to 2.88 eV for no background, PE max ∼ 284.4–284.5 eV), (ii) a series of silicon wafers with different oxide thicknesses (EW XPS ∼ 1.5–2.8 eV, PE max ∼ 99–103 eV), (iii) hydrogen-terminated silicon before and after derivatization with pentyl groups, and after annealing of

[Application Progress of Three-dimensional Laser Scanning Technology in Medical Surface Mapping].

Science.gov (United States)

Zhang, Yonghong; Hou, He; Han, Yuchuan; Wang, Ning; Zhang, Ying; Zhu, Xianfeng; Wang, Mingshi

2016-04-01

The booming three-dimensional laser scanning technology can efficiently and effectively get spatial three-dimensional coordinates of the detected object surface and reconstruct the image at high speed,high precision and large capacity of information.Non-radiation,non-contact and the ability of visualization make it increasingly popular in three-dimensional surface medical mapping.This paper reviews the applications and developments of three-dimensional laser scanning technology in medical field,especially in stomatology,plastic surgery and orthopedics.Furthermore,the paper also discusses the application prospects in the future as well as the biomedical engineering problems it would encounter with.

Characterization of the host response to the myxosporean parasite, Ceratomyxa shasta (Noble), by histology, scanning electron microscopy, and immunological techniques

Science.gov (United States)

Bartholomew, J.L.; Smith, C.E.; Rohovec, J.S.; Fryer, J.L.

1989-01-01

The tissue response of Salmo gairdneri Richardson, against the myxosporean parasite. Ceratomyxa shasta (Noble), was investigated using histological techniques, scanning electron microscopy and immunological methods. The progress of infection in C. shasta-susceptible and resistant steelhead and rainbow trout was examined by standard histological techniques and by indirect fluorescent antibody methods using monoclonal antibodies directed against C. shasta antigens. Trophozoite stages were first observed in the posterior intestine and there was indication that resistance was due to the inability of the parasite to penetrate this tissue rather than to an inflammatory response. Examination of a severely infected intestine by scanning electron microscopy showed extensive destruction of the mucosal folds of the posterior intestine. Western blotting and indirect fluorescent antibody techniques were used to investigate the immunological component of the host response. No antibodies specific for C. shasta were detected by either method.

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

Correlation among ultrasound, cross-sectional anatomy, and histology of the sciatic nerve: a review.

Science.gov (United States)

Moayeri, Nizar; van Geffen, Geert J; Bruhn, Jörgen; Chan, Vincent W; Groen, Gerbrand J

2010-01-01

Efficient identification of the sciatic nerve (SN) requires a thorough knowledge of its topography in relation to the surrounding structures. Anatomic cross sections in similar oblique planes as observed during SN ultrasonography are lacking. A survey of sonoanatomy matched with ultrasound views of the major SN block sites will be helpful in pattern recognition, especially when combined with images that show the internal architecture of the nerve. From 1 cadaver, consecutive parts of the upper leg corresponding to the 4 major blocks sites were sectioned and deeply frozen. Using cryomicrotomy, consecutive transverse sections were acquired and photographed at 78-microm intervals, along with histologic sections at 5-mm intervals. Multiplanar reformatting was done to reconstruct the optimal planes for an accurate comparison of ultrasonography and gross anatomy. The anatomic and histologic images were matched with ultrasound images that were obtained from 2 healthy volunteers. By simulating the exact position and angulation as in the ultrasonographic images, detailed anatomic overviews of SN and adjacent structures were reconstructed in the gluteal, subgluteal, midfemoral, and popliteal regions. Throughout its trajectory, SN contains numerous fascicles with connective and adipose tissues. In this study, we provide an optimal matching between histology, anatomic cross sections, and short-axis ultrasound images of SN. Reconstructing ultrasonographic planes with this high-resolution digitized anatomy not only enables an overview but also shows detailed views of the architecture of internal SN. The undulating course of the nerve fascicles within SN may explain its varying echogenic appearance during probe manipulation.

Towards Robust Self-Calibration for Handheld 3d Line Laser Scanning

Science.gov (United States)

Bleier, M.; Nüchter, A.

2017-11-01

This paper studies self-calibration of a structured light system, which reconstructs 3D information using video from a static consumer camera and a handheld cross line laser projector. Intersections between the individual laser curves and geometric constraints on the relative position of the laser planes are exploited to achieve dense 3D reconstruction. This is possible without any prior knowledge of the movement of the projector. However, inaccurrately extracted laser lines introduce noise in the detected intersection positions and therefore distort the reconstruction result. Furthermore, when scanning objects with specular reflections, such as glossy painted or metalic surfaces, the reflections are often extracted from the camera image as erroneous laser curves. In this paper we investiagte how robust estimates of the parameters of the laser planes can be obtained despite of noisy detections.

Efficient green lasers for high-resolution scanning micro-projector displays

Science.gov (United States)

Bhatia, Vikram; Bauco, Anthony S.; Oubei, Hassan M.; Loeber, David A. S.

2010-02-01

Laser-based projectors are gaining increased acceptance in mobile device market due to their low power consumption, superior image quality and small size. The basic configuration of such micro-projectors is a miniature mirror that creates an image by raster scanning the collinear red, blue and green laser beams that are individually modulated on a pixel-bypixel basis. The image resolution of these displays can be limited by the modulation bandwidth of the laser sources, and the modulation speed of the green laser has been one of the key limitations in the development of these displays. We will discuss how this limitation is fundamental to the architecture of many laser designs and then present a green laser configuration which overcomes these difficulties. In this green laser architecture infra-red light from a distributed Bragg-reflector (DBR) laser diode undergoes conversion to green light in a waveguided second harmonic generator (SHG) crystal. The direct doubling in a single pass through the SHG crystal allows the device to operate at the large modulation bandwidth of the DBR laser. We demonstrate that the resultant product has a small footprint (9% electrical-to-optical conversion) and large modulation bandwidth (>100 MHz).

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...

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.

Real-time depth monitoring and control of laser machining through scanning beam delivery system

International Nuclear Information System (INIS)

Ji, Yang; Grindal, Alexander W; Fraser, James M; Webster, Paul J L

2015-01-01

Scanning optics enable many laser applications in manufacturing because their low inertia allows rapid movement of the process beam across the sample. We describe our method of inline coherent imaging for real-time (up to 230 kHz) micron-scale (7–8 µm axial resolution) tracking and control of laser machining depth through a scanning galvo-telecentric beam delivery system. For 1 cm trench etching in stainless steel, we collect high speed intrapulse and interpulse morphology which is useful for further understanding underlying mechanisms or comparison with numerical models. We also collect overall sweep-to-sweep depth penetration which can be used for feedback depth control. For trench etching in silicon, we show the relationship of etch rate with average power and scan speed by computer processing of depth information without destructive sample post-processing. We also achieve three-dimensional infrared continuous wave (modulated) laser machining of a 3.96 × 3.96 × 0.5 mm 3 (length × width × maximum depth) pattern on steel with depth feedback. To the best of our knowledge, this is the first successful demonstration of direct real-time depth monitoring and control of laser machining with scanning optics. (paper)

Q-switched ruby laser irradiation of normal human skin. Histologic and ultrastructural findings.

Science.gov (United States)

Hruza, G J; Dover, J S; Flotte, T J; Goetschkes, M; Watanabe, S; Anderson, R R

1991-12-01

The Q-switched ruby laser is used for treatment of tatoos. The effects of Q-switched ruby laser pulses on sun-exposed and sun-protected human skin, as well as senile lentigines, were investigated with clinical observation, light microscopy, and transmission electron microscopy. A pinpricklike sensation occurred at radiant exposures as low as 0.2 J/cm2. Immediate erythema, delayed edema, and immediate whitening occurred with increasing radiant exposure. The threshold for immediate whitening varied inversely with skin pigmentation, ranging from a mean of 1.4 J/cm2 in lentigines to 3.1 J/cm2 in sun-protected skin. Transmission electron microscopy showed immediate alteration of mature melanosomes and nuclei within keratinocytes and melanocytes, but stage I and II melanosomes were unaffected. Histologically, immediate injury was confined to the epidermis. There was minimal inflammatory response 1 day after exposure. After 1 week, subthreshold exposures induced hyperpigmentation, with epidermal hyperplasia and increased melanin staining noted histologically. At higher radiant exposures, hypopigmentation occurred with desquamation of a pigmented scale/crust. All sites returned to normal skin color and texture without scarring within 3 to 6 months. These observations suggest that the human skin response to selective photothermolysis of pigmented cells is similar to that reported in animal models, including low radiant exposure stimulation of melanogenesis and high radiant exposure lethal injury to pigmented epidermal cells.

Laser Scanning in Engineering Surveying: Methods of Measurement and Modeling of Structures

Directory of Open Access Journals (Sweden)

Lenda Grzegorz

2016-06-01

Full Text Available The study is devoted to the uses of laser scanning in the field of engineering surveying. It is currently one of the main trends of research which is developed at the Department of Engineering Surveying and Civil Engineering at the Faculty of Mining Surveying and Environmental Engineering of AGH University of Science and Technology in Krakow. They mainly relate to the issues associated with tower and shell structures, infrastructure of rail routes, or development of digital elevation models for a wide range of applications. These issues often require the use of a variety of scanning techniques (stationary, mobile, but the differences also regard the planning of measurement stations and methods of merging point clouds. Significant differences appear during the analysis of point clouds, especially when modeling objects. Analysis of the selected parameters is already possible basing on ad hoc measurements carried out on a point cloud. However, only the construction of three-dimensional models provides complete information about the shape of structures, allows to perform the analysis in any place and reduces the amount of the stored data. Some structures can be modeled in the form of simple axes, sections, or solids, for others it becomes necessary to create sophisticated models of surfaces, depicting local deformations. The examples selected for the study allow to assess the scope of measurement and office work for a variety of uses related to the issue set forth in the title of this study. Additionally, the latest, forward-looking technology was presented - laser scanning performed from Unmanned Aerial Vehicles (drones. Currently, it is basically in the prototype phase, but it might be expected to make a significant progress in numerous applications in the field of engineering surveying.

A multiphoton laser scanning microscope setup for transcranial in vivo brain imaging on mice

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Nase, Gabriele; Helm, P. Johannes; Reppen, Trond; Ottersen, Ole Petter

2005-12-01

We describe a multiphoton laser scanning microscope setup for transcranial in vivo brain imaging in mice. The modular system is based on a modified industrial standard Confocal Scanning Laser Microscope (CSLM) and is assembled mainly from commercially available components. A special multifunctional stage, which is optimized for both laser scanning microscopic observation and preparative animal surgery, has been developed and built. The detection unit includes a highly efficient photomultiplier tube installed in a Peltier-cooled thermal box shielding the detector from changes in room temperature and from distortions caused by external electromagnetic fields. The images are recorded using a 12-bit analog-to-digital converter. Depending on the characteristics of the staining, individual nerve cells can be imaged down to at least 100μm below the intact cranium and down to at least 200μm below the opened cranium.

Can Low-Resolution Airborne Laser Scanning Data Be Used to Model Stream Rating Curves?

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Steve W. Lyon

2015-03-01

Full Text Available This pilot study explores the potential of using low-resolution (0.2 points/m2 airborne laser scanning (ALS-derived elevation data to model stream rating curves. Rating curves, which allow the functional translation of stream water depth into discharge, making them integral to water resource monitoring efforts, were modeled using a physics-based approach that captures basic geometric measurements to establish flow resistance due to implicit channel roughness. We tested synthetically thinned high-resolution (more than 2 points/m2 ALS data as a proxy for low-resolution data at a point density equivalent to that obtained within most national-scale ALS strategies. Our results show that the errors incurred due to the effect of low-resolution versus high-resolution ALS data were less than those due to flow measurement and empirical rating curve fitting uncertainties. As such, although there likely are scale and technical limitations to consider, it is theoretically possible to generate rating curves in a river network from ALS data of the resolution anticipated within national-scale ALS schemes (at least for rivers with relatively simple geometries. This is promising, since generating rating curves from ALS scans would greatly enhance our ability to monitor streamflow by simplifying the overall effort required.

Can low-resolution airborne laser scanning data be used to model stream rating curves?

Science.gov (United States)

Lyon, Steve; Nathanson, Marcus; Lam, Norris; Dahlke, Helen; Rutzinger, Martin; Kean, Jason W.; Laudon, Hjalmar

2015-01-01

This pilot study explores the potential of using low-resolution (0.2 points/m2) airborne laser scanning (ALS)-derived elevation data to model stream rating curves. Rating curves, which allow the functional translation of stream water depth into discharge, making them integral to water resource monitoring efforts, were modeled using a physics-based approach that captures basic geometric measurements to establish flow resistance due to implicit channel roughness. We tested synthetically thinned high-resolution (more than 2 points/m2) ALS data as a proxy for low-resolution data at a point density equivalent to that obtained within most national-scale ALS strategies. Our results show that the errors incurred due to the effect of low-resolution versus high-resolution ALS data were less than those due to flow measurement and empirical rating curve fitting uncertainties. As such, although there likely are scale and technical limitations to consider, it is theoretically possible to generate rating curves in a river network from ALS data of the resolution anticipated within national-scale ALS schemes (at least for rivers with relatively simple geometries). This is promising, since generating rating curves from ALS scans would greatly enhance our ability to monitor streamflow by simplifying the overall effort required.

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.

Comparison of bone-implant contact and bone-implant volume between 2D-histological sections and 3D-SRµCT slices

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R Bernhardt

2012-04-01

Full Text Available Histological imaging is still considered the gold standard for analysing bone formation around metallic implants. Generally, a limited number of histological sections per sample are used for the approximation of mean values of peri-implant bone formation. In this study we compared statistically the results of bone-implant contact (BIC and bone-implant volume (BIV obtained by histological sections, with those obtained by X-ray absorption images from synchrotron radiation micro-computed tomography (SRµCT using osseointegrated screw-shaped implants from a mini-pig study. Comparing the BIC results of 3-4 histological sections per implant sample with the appropriate 3-4 SRµCT slices showed a non-significant difference of 1.9 % (p = 0.703. The contact area assessed by the whole 3D information from the SRµCT measurement in comparison to the histomorphometric results showed a non-significant difference in BIC of 4.9 % (p = 0.171. The amount of the bone-implant volume in the histological sections and the appropriate SRµCT slices showed a non-significant difference by only 1.4 % (p = 0.736 and also remains non-significant with 2.6 % (p = 0.323 using the volumetric SRµCT information. We conclude that for a clinical evaluation of implant osseointegration with histological imaging at least 3-4 sections per sample are sufficient to represent the BIC or BIV for a sample. Due to the fact that in this study we have found a significant intra-sample variation in BIC of up to ± 35 % the selection of only one or two histological sections per sample may strongly influence the determined BIC.

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

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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.

Assessment of Relative Accuracy of AHN-2 Laser Scanning Data Using Planar Features

NARCIS (Netherlands)

Khoshelham, K.; Soudarissanane, S.; Van der Sande, C.

2010-01-01

AHN-2 is the second part of the Actueel Hoogtebestand Nederland project, which concerns the acquisition of high-resolution altimetry data over the entire Netherlands using airborne laser scanning. The accuracy assessment of laser altimetry data usually relies on comparing corresponding tie elements,

Scanning pattern angle effect on the resulting properties of selective laser sintered monolayers of Cu-Sn-Ni powder

Science.gov (United States)

Sabelle, Matías; Walczak, Magdalena; Ramos-Grez, Jorge

2018-01-01

Laser-based layer manufacturing of metals, also known as additive manufacturing, is a growing research field of academic and industrial interest. However, in the associated laser-driven processes (i.e. selective laser sintering (SLS) or melting (SLM)), optimization of some parameters has not been fully explored. This research aims at determining how the angle of laser scanning pattern (i.e. build orientation) in SLS affects the mechanical properties and structure of an individual Cu-Sn-Ni alloy metallic layer sintered in the process. Experiments consist in varying the angle of the scanning pattern (0°, 30°, 45° 60° and 90° relative to the transverse dimension of the piece), at constant scanning speed and laser beam power, producing specimens of different thicknesses. A noticeable effect of the scan angle on the mechanical strength and degree of densification of the sintered specimens is found. Thickness of the resulting monolayer correlates negatively with increasing scan angle, whereas relative density correlates positively. A minimum porosity and maximum UTS are found at the angle of 60°. It is concluded that angle of the scanning pattern angle plays a significant role in SLS of metallic monolayers.

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.

Action of diode laser (830 nm) on cutaneous wound healing process: biometrical and histological study in rats

International Nuclear Information System (INIS)

Rezende, Sandra Bastos

2001-01-01

In this research, it was analyzed the acceleration of the healing process of cutaneous lesions in mice, using a diode laser emitting in 830 nm. The 64 selected animals in this study were randomically divided into four groups of 16 animals each (G1, G2, G3 and G4). Biometric and histological comparisons were accomplished in the following periods: 3, 7 and 14 days after the surgery and laser application. Three laser irradiation configurations were used: a punctual contact (G2) and two non-contact and uniform (G3 and G4). For group G2, the laser intensity was 428 mW/cm 2 , and for groups G3 and G4 it was 53 mW/cm 2 . The total doses were D = 3 J/cm 2 for groups G2 and G4, and D = 1,3 J/cm 2 for G3. The first group, G1, was considered control and thus not submitted to any treatment after the surgery. All irradiated lesions presented acceleration of the healing process with regard to the control group. However, our results clearly indicate that the smaller laser intensity (uniform irradiation) leaded to the best results. On the other hand, the smaller used dose also leaded to the more significant and expressive results. The combination of the intensity value of 53 mW/cm 2 and the dose of 1,3 J/cm 2 leaded to optimal results, regarding the Biometric and histological analysis, presenting faster lesion contraction, quicker neoformation of epithelial and conjunctive tissue (with more collagen fibers ). (author)

Clinical and histological evaluation of laser therapy in the treatment of oral mucositis in an animal model

Science.gov (United States)

Vitória, L. A.; Machado, R. M.; Oliveira, C. R. B.; Rodriguez, T. T.; Cangussu, M. C. T.; Mathias, C. C.; Ramalho, L. M. P.

2018-04-01

Oral mucositis (MO) is considered to be the most severe stomatologic complication associated with antineoplastic treatment, which may lead to its interruption. Several current clinical protocols have aproven the benefits of Laser Photobiomodulation (LP) in the prevention and control of MO, due to its analgesic and anti-inflammatory effects and its stimulation of mesenchymal cells proliferation. The objective of this study was to evaluate the action of laser in initial events of chemo-induced MO. Eight Hamsters were divided into 2 groups (G): GI positive control (induction of MO) and GII Laser (induction of MO + Laser therapy). MO was induced by two injections of 5-Fluorouracil followed by grooves in the mucosa of the cheek pouch. The PL (Diode Laser of Gallium and Aluminum Arsenide, λ660nm, 40mW, 2,4J/cm2 ) was performed on day 0 of the experiment and every 48 hours until day 6. On day 7 the mucosa was photographed for clinical analysis according to Lima et al., 2005 and the animals were killed, for bag removal and histological processing for Hematoxylin and Eosin (H / E) staining. After statistical analysis (Fischer's Exact) with a significance level 0.5%, it was concluded that the LP, according to the adopted protocol, was able to prevent MO, and most hamsters showed no visible clinical changes in the cheek pouch. Histologically, it was observed that LP reduced angiogenesis and recruitment of inflammatory cells in G2. According to the results obtained LP was effective in preventing and reducing the severity of oral mucositis.

An Autonomous Ultra-Wide Band-Based Attitude and Position Determination Technique for Indoor Mobile Laser Scanning

Directory of Open Access Journals (Sweden)

Lawrence Lau

2018-04-01

Full Text Available Mobile laser scanning (MLS has been widely used in three-dimensional (3D city modelling data collection, such as Google cars for Google Map/Earth. Building Information Modelling (BIM has recently emerged and become prominent. 3D models of buildings are essential for BIM. Static laser scanning is usually used to generate 3D models for BIM, but this method is inefficient if a building is very large, or it has many turns and narrow corridors. This paper proposes using MLS for BIM 3D data collection. The positions and attitudes of the mobile laser scanner are important for the correct georeferencing of the 3D models. This paper proposes using three high-precision ultra-wide band (UWB tags to determine the positions and attitudes of the mobile laser scanner. The accuracy of UWB-based MLS 3D models is assessed by comparing the coordinates of target points, as measured by static laser scanning and a total station survey.

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.

Laser scanning confocal microscope with programmable amplitude, phase, and polarization of the illumination beam.

Science.gov (United States)

Boruah, B R; Neil, M A A

2009-01-01

We describe the design and construction of a laser scanning confocal microscope with programmable beam forming optics. The amplitude, phase, and polarization of the laser beam used in the microscope can be controlled in real time with the help of a liquid crystal spatial light modulator, acting as a computer generated hologram, in conjunction with a polarizing beam splitter and two right angled prisms assembly. Two scan mirrors, comprising an on-axis fast moving scan mirror for line scanning and an off-axis slow moving scan mirror for frame scanning, configured in a way to minimize the movement of the scanned beam over the pupil plane of the microscope objective, form the XY scan unit. The confocal system, that incorporates the programmable beam forming unit and the scan unit, has been implemented to image in both reflected and fluorescence light from the specimen. Efficiency of the system to programmably generate custom defined vector beams has been demonstrated by generating a bottle structured focal volume, which in fact is the overlap of two cross polarized beams, that can simultaneously improve both the lateral and axial resolutions if used as the de-excitation beam in a stimulated emission depletion confocal microscope.

Accuracy assessment of airborne laser scanning strips using planar features

NARCIS (Netherlands)

Soudarissanane, S.S.; Van der Sande, C.J.; Khoshelham, K.

2010-01-01

Airborne Laser Scanning (ALS) is widely used in many applications for its high measurement accuracy, fast acquisition capability, and large spatial coverage. Accuracy assessment of the ALS data usually relies on comparing corresponding tie elements, often points or lines, in the overlapping strips.

Scanning vs. single spot laser ablation (λ=213 nm) inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Gonzalez, Jhanis J.; Fernandez, Alberto; Mao Xianglei; Russo, Richard E.

2004-01-01

Sampling strategy is defined in this work as the interaction of a repetitively pulsed laser beam with a fixed position on a sample (single spot) or with a moving sample (scan). Analytical performance of these sampling strategies was compared by using 213 nm laser ablation ICP-MS. A geological rock (Tuff) was quantitatively analyzed based on NIST series 610-616 glass standard reference materials. Laser ablation data were compared to ICP-MS analysis of the dissolved samples. The scan strategy (50 μm/s) produced a flat, steady temporal ICP-MS response whereas the single spot strategy produced a signal that decayed with time (after 60 s). Single-spot sampling provided better accuracy and precision than the scan strategy when the first 15 s of the sampling time was eliminated from the data analysis. In addition, the single spot strategy showed less matrix dependence among the four NIST glasses

The equivalent width as a figure of merit for XPS narrow scans

Energy Technology Data Exchange (ETDEWEB)

Singh, Bhupinder [Department of Chemistry and Biochemistry, C-100 BNSN, Brigham Young University, Provo, UT 84602 (United States); Velázquez, Daniel [Department of Physics, Illinois Institute of Technology, Chicago, IL 60616 (United States); Terry, Jeff, E-mail: terryj@iit.edu [Department of Physics, Illinois Institute of Technology, Chicago, IL 60616 (United States); Linford, Matthew R., E-mail: mrlinford@chem.byu.edu [Department of Chemistry and Biochemistry, C-100 BNSN, Brigham Young University, Provo, UT 84602 (United States)

2014-12-15

Highlights: • We introduce a new figure of merit for XPS narrow scans: the equivalent width (EW{sub XPS}). • EW{sub XPS} is less subjective and involves lesser user bias than traditional peak fitting. • EW{sub XPS} is responsive to changes in chemical states of materials. • EW{sub XPS} could be used for quality control and comparing spectra from similar samples. • EW{sub XPS} has the potential to be part of an expert software system for machine interpretation of spectra. - Abstract: X-ray Photoelectron Spectroscopy (XPS) is a widely used surface analytical tool that provides information about the near surface regions of materials. And while indispensable for XPS data analysis, peak fitting of narrow scans is often a fairly subjective exercise. Herein we introduce the equivalent width (EW) as an additional and less subjective figure of merit for XPS narrow scans. We believe that this parameter will prove particularly useful for analyzing series of similar or nominally identical spectra, perhaps as a component of an expert software system for the machine interpretation of spectra. It also appears to be useful, shedding light on the chemical state of materials, when additional information about a sample is known. The EW{sub XPS} is simply defined as the area of a narrow scan divided by the height of the maximum of its peak envelope. To limit any ambiguity in EW{sub XPS} for a series of spectra, we may also list the peak position of the maximum of the envelope (PE{sub max}). The potential usefulness and limitations of the EW{sub XPS} and PE{sub max} parameters are demonstrated by their application to the narrow scans of: (i) four sets of ozone-treated carbon nanotubes (EW{sub XPS} ∼ 2.11–2.16 eV for a Shirley background, and up to 2.88 eV for no background, PE{sub max} ∼ 284.4–284.5 eV), (ii) a series of silicon wafers with different oxide thicknesses (EW{sub XPS} ∼ 1.5–2.8 eV, PE{sub max} ∼ 99–103 eV), (iii) hydrogen-terminated silicon before

Metabolite localization by atmospheric pressure high-resolution scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging in whole-body sections and individual organs of the rove beetle Paederus riparius.

Science.gov (United States)

Bhandari, Dhaka Ram; Schott, Matthias; Römpp, Andreas; Vilcinskas, Andreas; Spengler, Bernhard

2015-03-01

Mass spectrometry imaging provides for non-targeted, label-free chemical imaging. In this study, atmospheric pressure high-resolution scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging (AP-SMALDI MSI) was used for the first time to describe the chemical distribution of the defensive compounds pederin, pseudopederin, and pederon in tissue sections (16 μm thick) of the rove beetle Paederus riparius. The whole-insect tissue section was scanned with a 20-μm step size. Mass resolution of the orbital trapping mass spectrometer was set to 100,000 at m/z 200. Additionally, organ-specific compounds were identified for brain, nerve cord, eggs, gut, ovaries, and malpighian tubules. To confirm the distribution of the specific compounds, individual organs from the insect were dissected, and MSI experiments were performed on the dissected organs. Three ganglia of the nerve cord, with a dimension of 250-500 μm, were measured with 10-μm spatial resolution. High-quality m/z images, based on high spatial resolution and high mass accuracy were generated. These features helped to assign mass spectral peaks with high confidence. Mass accuracy of the imaging experiments was section. Without any labeling, we assigned key lipids for specific organs to describe their location in the body and to identify morphological structures with a specificity higher than with staining or immunohistology methods.

When machine vision meets histology: A comparative evaluation of model architecture for classification of histology sections.

Science.gov (United States)

Zhong, Cheng; Han, Ju; Borowsky, Alexander; Parvin, Bahram; Wang, Yunfu; Chang, Hang

2017-01-01

Classification of histology sections in large cohorts, in terms of distinct regions of microanatomy (e.g., stromal) and histopathology (e.g., tumor, necrosis), enables the quantification of tumor composition, and the construction of predictive models of genomics and clinical outcome. To tackle the large technical variations and biological heterogeneities, which are intrinsic in large cohorts, emerging systems utilize either prior knowledge from pathologists or unsupervised feature learning for invariant representation of the underlying properties in the data. However, to a large degree, the architecture for tissue histology classification remains unexplored and requires urgent systematical investigation. This paper is the first attempt to provide insights into three fundamental questions in tissue histology classification: I. Is unsupervised feature learning preferable to human engineered features? II. Does cellular saliency help? III. Does the sparse feature encoder contribute to recognition? We show that (a) in I, both Cellular Morphometric Feature and features from unsupervised feature learning lead to superior performance when compared to SIFT and [Color, Texture]; (b) in II, cellular saliency incorporation impairs the performance for systems built upon pixel-/patch-level features; and (c) in III, the effect of the sparse feature encoder is correlated with the robustness of features, and the performance can be consistently improved by the multi-stage extension of systems built upon both Cellular Morphmetric Feature and features from unsupervised feature learning. These insights are validated with two cohorts of Glioblastoma Multiforme (GBM) and Kidney Clear Cell Carcinoma (KIRC). Copyright © 2016 Elsevier B.V. All rights reserved.

Histological study of subcutaneous fat at NIR laser treatment of the rat skin in vivo

Science.gov (United States)

Yanina, I. Y.; Svenskaya, Yu. I.; Navolokin, N. A.; Matveeva, O. V.; Bucharskaya, A. B.; Maslyakova, G. N.; Gorin, D. A.; Sukhorukov, G. B.; Tuchin, V. V.

2015-07-01

The goal of this work is to quantify impact of in vivo photochemical treatment using indocyanine green (ICG) or encapsulated ICG and NIR laser irradiation through skin of rat with obesity by the follow up tissue sampling and histochemistry. After 1 hour elapsed since 1-min light exposure samples of rat skin with subcutaneous tissue of thickness of 1.5-2.5 mm were taken by surgery from rats within marked 4-zones of the skin site. For hematoxylin-eosin histological examination of excised tissue samples, fixation was carried out by 10%-formaldehyde solution. For ICG and encapsulated ICG subcutaneous injection and subsequent 1-min diode laser irradiation with power density of 8 W/cm2, different necrotic regions with lipolysis of subcutaneous fat were observed. The obtained data can be used for safe layer-by-layer laser treatment of obesity and cellulite.

Histological examination of the oral mucosa after fractional diode laser irradiation with different power and pulse duration

Science.gov (United States)

Belikov, Andrey V.; Ermolaeva, Ludmila A.; Korzhevsky, Dmitriy E.; Sergeeva, Elena S.; Semyashkina, Yulia V.; Antropova, Maria M.; Fedotov, Denis Y.; Zaitseva, Maria A.; Kashina, Tatiana V.

2018-04-01

Optical and histological methods were used to examination of influence the power and pulse duration of 980-nm diode laser to the dimensions and morphology of tissue around fractional micro injuries created by the radiation of that laser in the oral mucosa of rats in vivo. The power of laser radiation (P) varied in the range of 1÷21 W, and its pulse duration (tp) - in the range 50÷500 ms. Histological examination showed that in the mucosa of the oral cavity after the laser fractional irradiation, there following effects are found: a tissue defect, a transudate in the lumen of ablative micro injury, stretching and compacting effect of the nuclei of the basal epithelium, the disappearance of granules of the keratohialin, destroying the structure of the connective tissue, erythrocyte stasis in the vessels, the disappearance of transverse striation in the muscle fibers in muscle layer. It has been found that ablative micro injury begins to form up at P = 5 W, tp = 100 ms and affects only the epithelial layer of the mucosa. At P = 7 W, tp = 120 ms, the ratio of width to depth of ablative micro injury is 1 : 1, and at P = 10 W, tp = 100 ms, an ablative micro column with ratio of 1 : 1.5 is formed in the epithelial and submucosal layers of the mucosa. The laser effect with P = 15 W, tp = 200 ms leads to lengthening of the ablation micro-column to 1 : 2, with the bottom of the ablative micro column reaching the muscular layer. With a further growth of laser power or pulse duration, the width of the micro injury increases, and the growth of the micro injury depth is slowed down so that the micro column buildup is ceased.

Multi-Resolution Wavelet-Transformed Image Analysis of Histological Sections of Breast Carcinomas

Directory of Open Access Journals (Sweden)

Hae-Gil Hwang

2005-01-01

Full Text Available Multi-resolution images of histological sections of breast cancer tissue were analyzed using texture features of Haar- and Daubechies transform wavelets. Tissue samples analyzed were from ductal regions of the breast and included benign ductal hyperplasia, ductal carcinoma in situ (DCIS, and invasive ductal carcinoma (CA. To assess the correlation between computerized image analysis and visual analysis by a pathologist, we created a two-step classification system based on feature extraction and classification. In the feature extraction step, we extracted texture features from wavelet-transformed images at 10× magnification. In the classification step, we applied two types of classifiers to the extracted features, namely a statistics-based multivariate (discriminant analysis and a neural network. Using features from second-level Haar transform wavelet images in combination with discriminant analysis, we obtained classification accuracies of 96.67 and 87.78% for the training and testing set (90 images each, respectively. We conclude that the best classifier of carcinomas in histological sections of breast tissue are the texture features from the second-level Haar transform wavelet images used in a discriminant function.

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

Pattern scan laser versus single spot laser in panretinal photocoagulation treatment for proliferative diabetic retinopathy

Directory of Open Access Journals (Sweden)

Shu Zhang

2017-02-01

Full Text Available AIM: To investigate the efficacy of 577-nm pattern scan laser in panretinal photocoagulation(PRPtreatment in newly diagnosed proliferative diabetic retinopathy(PDR.METHODS:Prospective and comparative observation was performed in totally 32 patients with high-risk PDR. They were randomly divided into group 1(using pattern scan laser, PSLand 2(using single spot laser, SSL, each containing 16 subjects to which totally 20 eyes received PRP. Non-perfusion region was identified with fundus fluorescein angiography(FFAbefore and 3mo after final PRP. The advantage of PSL was verified in terms of the number and the duration of PRP sessions needed for satisfactory outcomes, and the pain score.RESULTS: Three PRP sessions were needed for each eye to complete the treatment using PSL, while 4 sessions were needed using SSL. The duration of each session with PSL in group 1 was 7.3±2.3min, which was significantly shorter than that with SSL in group 2(13.2±4.1, t38=5.596, PPCONCLUSION: PSL showed clear advantages over SSL in the PRP treatment of PDR, not only in the improved efficacy, but also in the reduction of pain and the improvement of effectiveness.

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 is to dev......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......, the problem is a combination of combinatorial and choice optimization, which makes the problem difficult to solve. On a process simulation domain consisting of 32 cells, our multi-objective evolutionary method is able to find a set of trade-off solutions for the defined conflicting objectives, which cannot...

Application of the laser scanning confocal microscope in fluorescent film sensor research

Science.gov (United States)

Zhang, Hongyan; Liu, Wei-Min; Zhao, Wen-Wen; Dai, Qing; Wang, Peng-Fei

2010-10-01

Confocal microscopy offers several advantages over conventional optical microscopy; we show an experimental investigation laser scanning confocal microscope as a tool to be used in cubic boron nitride (cBN) film-based fluorescent sensor research. Cubic boron nitride cBN film sensors are modified with dansyl chloride and rhodamine B isothiocyanate respectively. Fluorescent modification quality on the cubic boron nitride film is clearly express and the sensor ability to Hg2+ cations and pH are investigated in detail. We evidence the rhodamine B isothiocyanate modified quality on cBN surface is much better than that of dansyl chloride. And laser scanning confocal microscope has potential application lighttight fundus film fluorescent sensor research.

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.

Data acquisition considerations for Terrestrial Laser Scanning of forest plots

NARCIS (Netherlands)

Wilkes, Phil; Lau Sarmiento, Alvaro; Disney, Mathias; Calders, Kim; Burt, Andrew; Gonzalez De Tanago Meñaca, J.; Bartholomeus, Harm; Brede, Benjamin; Herold, Martin

2017-01-01

The poor constraint of forest Above Ground Biomass (AGB) is responsible, in part, for large uncertainties in modelling future climate scenarios. Terrestrial Laser Scanning (TLS) can be used to derive unbiased and non-destructive estimates of tree structure and volume and can, therefore, be used to

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.

Axial Fan Blade Vibration Assessment under Inlet Cross-Flow Conditions Using Laser Scanning Vibrometry

Directory of Open Access Journals (Sweden)

Till Heinemann

2017-08-01

Full Text Available In thermal power plants equipped with air-cooled condensers (ACCs, axial cooling fans operate under the influence of ambient flow fields. Under inlet cross-flow conditions, the resultant asymmetric flow field is known to introduce additional harmonic forces to the fan blades. This effect has previously only been studied numerically or by using blade-mounted strain gauges. For this study, laser scanning vibrometry (LSV was used to assess fan blade vibration under inlet cross-flow conditions in an adapted fan test rig inside a wind tunnel test section. Two co-rotating laser beams scanned a low-pressure axial fan, resulting in spectral, phase-resolved surface vibration patterns of the fan blades. Two distinct operating points with flow coefficients of 0.17 and 0.28 were examined, with and without inlet cross-flow influence. While almost identical fan vibration patterns were found for both reference operating points, the overall blade vibration increased by 100% at the low fan flow rate as a result of cross-flow, and by 20% at the high fan flow rate. While numerically predicted natural frequency modes could be confirmed from experimental data as minor peaks in the vibration amplitude spectrum, they were not excited significantly by cross-flow. Instead, primarily higher rotation-rate harmonics were amplified; that is, a synchronous blade-tip flapping was strongly excited at the blade-pass frequency.

Acquiring a 2D rolled equivalent fingerprint image from a non-contact 3D finger scan

Science.gov (United States)

Fatehpuria, Abhishika; Lau, Daniel L.; Hassebrook, Laurence G.

2006-04-01

The use of fingerprints as a biometric is both the oldest mode of computer aided personal identification and the most relied-upon technology in use today. But current fingerprint scanning systems have some challenging and peculiar difficulties. Often skin conditions and imperfect acquisition circumstances cause the captured fingerprint image to be far from ideal. Also some of the acquisition techniques can be slow and cumbersome to use and may not provide the complete information required for reliable feature extraction and fingerprint matching. Most of the difficulties arise due to the contact of the fingerprint surface with the sensor platen. To attain a fast-capture, non-contact, fingerprint scanning technology, we are developing a scanning system that employs structured light illumination as a means for acquiring a 3-D scan of the finger with sufficiently high resolution to record ridge-level details. In this paper, we describe the postprocessing steps used for converting the acquired 3-D scan of the subject's finger into a 2-D rolled equivalent image.

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.

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

International Nuclear Information System (INIS)

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

2017-01-01

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. (paper)

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.

Histological Evidence of the Osseointegration of Fractured Direct Metal Laser Sintering Implants Retrieved after 5 Years of Function

Directory of Open Access Journals (Sweden)

Francesco Mangano

2017-01-01

Full Text Available Background. Direct metal laser sintering (DMLS is an additive manufacturing technique that allows the fabrication of dental implants layer by layer through the laser fusion of titanium microparticles. The surface of DMLS implants is characterized by a high open porosity with interconnected pores of different sizes; therefore, it has the potential to enhance and accelerate bone healing. To date, however, there are no histologic/histomorphometric studies in the literature evaluating the interface between bone and DMLS implants in the long-term. Purpose. To evaluate the interface between bone and DMLS implants retrieved after 5 years of functional loading. Methods. Two fractured DMLS implants were retrieved from the human jaws, using a 5 mm trephine bur. Both the implants were clinically stable and functioned regularly before fracture. The specimens were processed for histologic/histomorphometric evaluation; the bone-to-implant contact (BIC% was calculated. Results. Compact, mature lamellar bone was found over most of the DMLS implants in close contact with the implant surface; the histomorphometric evaluation showed a mean BIC% of 66.1% (±4.5%. Conclusions. The present histologic/histomorphometric study showed that DMLS implants were well integrated in bone, after 5 years of loading, with the peri-implant bone undergoing continuous remodeling at the interface.

Histological Evidence of the Osseointegration of Fractured Direct Metal Laser Sintering Implants Retrieved after 5 Years of Function

Science.gov (United States)

Piattelli, Adriano

2017-01-01

Background Direct metal laser sintering (DMLS) is an additive manufacturing technique that allows the fabrication of dental implants layer by layer through the laser fusion of titanium microparticles. The surface of DMLS implants is characterized by a high open porosity with interconnected pores of different sizes; therefore, it has the potential to enhance and accelerate bone healing. To date, however, there are no histologic/histomorphometric studies in the literature evaluating the interface between bone and DMLS implants in the long-term. Purpose To evaluate the interface between bone and DMLS implants retrieved after 5 years of functional loading. Methods Two fractured DMLS implants were retrieved from the human jaws, using a 5 mm trephine bur. Both the implants were clinically stable and functioned regularly before fracture. The specimens were processed for histologic/histomorphometric evaluation; the bone-to-implant contact (BIC%) was calculated. Results Compact, mature lamellar bone was found over most of the DMLS implants in close contact with the implant surface; the histomorphometric evaluation showed a mean BIC% of 66.1% (±4.5%). Conclusions The present histologic/histomorphometric study showed that DMLS implants were well integrated in bone, after 5 years of loading, with the peri-implant bone undergoing continuous remodeling at the interface. PMID:28929117

Histological Evidence of the Osseointegration of Fractured Direct Metal Laser Sintering Implants Retrieved after 5 Years of Function.

Science.gov (United States)

Mangano, Francesco; Mangano, Carlo; Piattelli, Adriano; Iezzi, Giovanna

2017-01-01

Direct metal laser sintering (DMLS) is an additive manufacturing technique that allows the fabrication of dental implants layer by layer through the laser fusion of titanium microparticles. The surface of DMLS implants is characterized by a high open porosity with interconnected pores of different sizes; therefore, it has the potential to enhance and accelerate bone healing. To date, however, there are no histologic/histomorphometric studies in the literature evaluating the interface between bone and DMLS implants in the long-term. To evaluate the interface between bone and DMLS implants retrieved after 5 years of functional loading. Two fractured DMLS implants were retrieved from the human jaws, using a 5 mm trephine bur. Both the implants were clinically stable and functioned regularly before fracture. The specimens were processed for histologic/histomorphometric evaluation; the bone-to-implant contact (BIC%) was calculated. Compact, mature lamellar bone was found over most of the DMLS implants in close contact with the implant surface; the histomorphometric evaluation showed a mean BIC% of 66.1% (±4.5%). The present histologic/histomorphometric study showed that DMLS implants were well integrated in bone, after 5 years of loading, with the peri-implant bone undergoing continuous remodeling at the interface.

Scanning thin-sheet laser imaging microscopy (sTSLIM) with structured illumination and HiLo background rejection.

Science.gov (United States)

Schröter, Tobias J; Johnson, Shane B; John, Kerstin; Santi, Peter A

2012-01-01

We report replacement of one side of a static illumination, dual sided, thin-sheet laser imaging microscope (TSLIM) with an intensity modulated laser scanner in order to implement structured illumination (SI) and HiLo image demodulation techniques for background rejection. The new system is equipped with one static and one scanned light-sheet and is called a scanning thin-sheet laser imaging microscope (sTSLIM). It is an optimized version of a light-sheet fluorescent microscope that is designed to image large specimens (HiLo image demodulation. The static light-sheet has a thickness of 3.2 µm; whereas, the scanned side has a light-sheet thickness of 4.2 µm. The scanned side images specimens with subcellular resolution (HiLo produce superior contrast compared to both the uniform static and scanned light-sheets. HiLo contrast was greater than SI and is faster and more robust than SI because as it produces images in two-thirds of the time and exhibits fewer intensity streaking artifacts. 2011 Optical Society of America

3D laser scanning and modelling of the Dhow heritage for the Qatar National Museum

Science.gov (United States)

Wetherelt, A.; Cooper, J. P.; Zazzaro, C.

2014-08-01

Curating boats can be difficult. They are complex structures, often demanding to conserve whether in or out of the water; they are usually large, difficult to move on land, and demanding of gallery space. Communicating life on board to a visiting public in the terra firma context of a museum can be difficult. Boats in their native environment are inherently dynamic artifacts. In a museum they can be static and divorced from the maritime context that might inspire engagement. New technologies offer new approaches to these problems. 3D laser scanning and digital modeling offers museums a multifaceted means of recording, monitoring, studying and communicating watercraft in their care. In this paper we describe the application of 3D laser scanning and subsequent digital modeling. Laser scans were further developed using computer-generated imagery (CGI) modeling techniques to produce photorealistic 3D digital models for development into interactive, media-based museum displays. The scans were also used to generate 2D naval lines and orthographic drawings as a lasting curatorial record of the dhows held by the National Museum of Qatar.

Wafer-level vacuum packaged resonant micro-scanning mirrors for compact laser projection displays

Science.gov (United States)

Hofmann, Ulrich; Oldsen, Marten; Quenzer, Hans-Joachim; Janes, Joachim; Heller, Martin; Weiss, Manfred; Fakas, Georgios; Ratzmann, Lars; Marchetti, Eleonora; D'Ascoli, Francesco; Melani, Massimiliano; Bacciarelli, Luca; Volpi, Emilio; Battini, Francesco; Mostardini, Luca; Sechi, Francesco; De Marinis, Marco; Wagner, Bernd

2008-02-01

Scanning laser projection using resonant actuated MEMS scanning mirrors is expected to overcome the current limitation of small display size of mobile devices like cell phones, digital cameras and PDAs. Recent progress in the development of compact modulated RGB laser sources enables to set up very small laser projection systems that become attractive not only for consumer products but also for automotive applications like head-up and dash-board displays. Within the last years continuous progress was made in increasing MEMS scanner performance. However, only little is reported on how mass-produceability of these devices and stable functionality even under harsh environmental conditions can be guaranteed. Automotive application requires stable MEMS scanner operation over a wide temperature range from -40° to +85°Celsius. Therefore, hermetic packaging of electrostatically actuated MEMS scanning mirrors becomes essential to protect the sensitive device against particle contamination and condensing moisture. This paper reports on design, fabrication and test of a resonant actuated two-dimensional micro scanning mirror that is hermetically sealed on wafer level. With resonant frequencies of 30kHz and 1kHz, an achievable Theta-D-product of 13mm.deg and low dynamic deformation <20nm RMS it targets Lissajous projection with SVGA-resolution. Inevitable reflexes at the vacuum package surface can be seperated from the projection field by permanent inclination of the micromirror.

Defining the Cubature Changes of Historic St. Kinga Chamber in Bochnia Salt Mine, Using Laser Scanning Technology

Science.gov (United States)

Szafarczyk, Anna; Gawałkiewicz, Rafał

2018-03-01

In Poland, there are many mining enterprises, of historic character registered in the UNESCO World Heritage List. One of the oldest mining enterprises in Poland is the Salt Mine in Bochnia. The processes inside the rock mass require that surveying services carry out regular geometric control of the cavities. A particular attention should be paid (due to its sacral function) on St. Kinga Chamber, located 195 metres below the surface, on the mine level "August". So far measurement technologies have been connected with the studies on changes in the geometry of cavities and based on linear bases used to measure convergence. This only provides discrete information (in a point) and not always presents a real state of deformation. In the scanning method, in practice a three dimension image of changes (structural deformations) is obtained, impossible to determine with the application of measurement methods, applied to measure the value of linear convergence (the method with a limited number of bases). Laser scanning, apart from determining the value of volume convergence, gives also the possibility of the visualization of 3D cavern. Moreover, it provides direct information to update mining numerical maps and make it possible to generate various cross-sections through the cavern. The authors analysed the possibility of the application of laser scanning (scanner Faro Focus 3D), as a modern tool allowing the measuring of the value of volume convergence.

Effect of laser power and scanning speed on laser deposited Ti6Al4V/TiB2 matrix composites

CSIR Research Space (South Africa)

Mokgalaka, MN

2012-10-01

Full Text Available Additive Manufacturing in Industry Conference, Kwa Maritane, Pilanesberg National Park, 31 October-2 November 2012 EFFECT OF LASER POWER AND SCANNING SPEED ON LASER DEPOSITED Ti6Al4V/TiB2 MATRIX COMPOSITES M.N. Mokgalaka2,1, S.L. Pityana1,2, A.P.I...

Multiphoton microscopic imaging of histological sections without hematoxylin and eosin staining differentiates carcinoma in situ lesion from normal oesophagus

Science.gov (United States)

Chen, Jianxin; Xu, Jian; Kang, Deyong; Xu, Meifang; Zhuo, Shuangmu; Zhu, Xiaoqin; Jiang, Xingshan

2013-10-01

Multiphoton microscopy (MPM) has become a powerful, important tool for tissues imaging at the molecular level. In this paper, this technique was extended to histological investigations, differentiating carcinoma in situ (CIS) lesion from normal oesophagus by imaging histological sections without hematoxylin and eosin (H&E) staining. The results show that the histology procedures of dehydration, paraffin embedding, and de-paraffinizing highlighted two photon excited fluorescence of cytoplasm and nucleolus of epithelial cell and collagen in stroma. MPM has the ability to identify the characteristics of CIS lesion including changes of squamous cells and full epithelium, identification of basement membrane, especially prominent nucleolus. The studies described here show that MPM has the potential for future retrospective studies of tumor staging by employing on histological section specimens without H&E staining.

Endoanal MRI of the anal sphincter complex: correlation with cross-sectional anatomy and histology

NARCIS (Netherlands)

S.M. Hussain (Shahid); J. Stoker (Jacob); A.W. Zwamborn; J.C. den Hollander (Jan); J.-W. Kuiper (Jan-Willem); C.A. Entius; J.S. Lameris

1996-01-01

textabstractThe purpose of this study was to correlate the in vivo endoanal MRI findings of the anal sphincter with the cross-sectional anatomy and histology. Fourteen patients with rectal tumours were examined with a rigid endoanal MR coil before undergoing

Influence of laser ablation parameters on trueness of imaging

International Nuclear Information System (INIS)

Vaculovič, T.; Warchilová, T.; Čadková, Z.; Száková, J.; Tlustoš, P.; Otruba, V.; Kanický, V.

2015-01-01

Highlights: • Laser ablation conditions vs. quality of LA-ICP-MS imaging (resolution, detection). • Increase in laser spot size improves detection limit, while deteriorates resolution. • Decrease in scan speed improves resolution but prolongs time of analysis. • Compromise spot size and scan speed meet required quality of imaging. • Metal-enriched/depleted zones in tapeworm sections were resolved by LA-ICP-MS. - Abstract: Influence of laser ablation conditions on limit of detection, spatial resolution and time of analysis was studied for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) applied to elemental mapping. Laser repetition rate and laser fluence were investigated in tapeworm thin section to attain optimum ablation rate, yielding appropriately low detection limit which complies with elemental contents in the tissue. Effect of combinations of laser spot size and scan speed on relative broadening (Δw rel ) of image of the ablated pattern (line) was investigated with the aim to quantify the trueness of imaging. Ink lines printed on paper were employed for the study of influence of spot size and scan speed on limit of detection, relative broadening of elemental image and duration of elemental mapping. An uneven distribution of copper in a printed line (coffee stain effect) was observed. The Δw rel is strongly reduced (down to 2%) at low scan speed (10 μm s −1 ) and laser spot diameter of 10 μm but resulting in unacceptably long time of mapping (up to 3000 min). Finally, tapeworm thin-section elemental maps (4 mm × 5 mm) were obtained at the laser spot diameter of 65 μm and the scan speed of 65 μm s −1 within 100 min. A dissimilar lateral distribution of Pb was observed in comparison with that of Cu or Zn due to different pathways of element uptake

Influence of laser ablation parameters on trueness of imaging

Energy Technology Data Exchange (ETDEWEB)

Vaculovič, T.; Warchilová, T. [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, Brno 61137 (Czech Republic); CEITEC, Masaryk University, Kamenice 5, Brno 62500 (Czech Republic); Čadková, Z.; Száková, J.; Tlustoš, P. [Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcka 129, Praha 16521 (Czech Republic); Otruba, V. [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, Brno 61137 (Czech Republic); Kanický, V., E-mail: viktork@chemi.muni.cz [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, Brno 61137 (Czech Republic); CEITEC, Masaryk University, Kamenice 5, Brno 62500 (Czech Republic)

2015-10-01

Highlights: • Laser ablation conditions vs. quality of LA-ICP-MS imaging (resolution, detection). • Increase in laser spot size improves detection limit, while deteriorates resolution. • Decrease in scan speed improves resolution but prolongs time of analysis. • Compromise spot size and scan speed meet required quality of imaging. • Metal-enriched/depleted zones in tapeworm sections were resolved by LA-ICP-MS. - Abstract: Influence of laser ablation conditions on limit of detection, spatial resolution and time of analysis was studied for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) applied to elemental mapping. Laser repetition rate and laser fluence were investigated in tapeworm thin section to attain optimum ablation rate, yielding appropriately low detection limit which complies with elemental contents in the tissue. Effect of combinations of laser spot size and scan speed on relative broadening (Δw{sub rel}) of image of the ablated pattern (line) was investigated with the aim to quantify the trueness of imaging. Ink lines printed on paper were employed for the study of influence of spot size and scan speed on limit of detection, relative broadening of elemental image and duration of elemental mapping. An uneven distribution of copper in a printed line (coffee stain effect) was observed. The Δw{sub rel} is strongly reduced (down to 2%) at low scan speed (10 μm s{sup −1}) and laser spot diameter of 10 μm but resulting in unacceptably long time of mapping (up to 3000 min). Finally, tapeworm thin-section elemental maps (4 mm × 5 mm) were obtained at the laser spot diameter of 65 μm and the scan speed of 65 μm s{sup −1} within 100 min. A dissimilar lateral distribution of Pb was observed in comparison with that of Cu or Zn due to different pathways of element uptake.

Test field for airborne laser scanning in Finland

Science.gov (United States)

Ahokas, E.; Kaartinen, H.; Kukko, A.; Litkey, P.

2014-11-01

Airborne laser scanning (ALS) is a widely spread operational measurement tool for obtaining 3D coordinates of the ground surface. There is a need for calibrating the ALS system and a test field for ALS was established at the end of 2013. The test field is situated in the city of Lahti, about 100 km to the north of Helsinki. The size of the area is approximately 3.5 km × 3.2 km. Reference data was collected with a mobile laser scanning (MLS) system assembled on a car roof. Some streets were measured both ways and most of them in one driving direction only. The MLS system of the Finnish Geodetic Institute (FGI) consists of a navigation system (NovAtel SPAN GNSS-IMU) and a laser scanner (FARO Focus3D 120). In addition to the MLS measurements more than 800 reference points were measured using a Trimble R8 VRS-GNSS system. Reference points are along the streets, on parking lots, and white pedestrian crossing line corners which can be used as reference targets. The National Land Survey of Finland has already used this test field this spring for calibrating their Leica ALS-70 scanner. Especially it was easier to determine the encoder scale factor parameter using this test field. Accuracy analysis of the MLS points showed that the point height RMSE is 2.8 cm and standard deviation is 2.6 cm. Our purpose is to measure both more MLS data and more reference points in the test field area to get a better spatial coverage. Calibration flight heights are planned to be 1000 m and 2500 m above ground level. A cross pattern, southwest-northeast and northwest-southeast, will be flown both in opposite directions.

Integrating Airborne and Terrestrial Laser Scanning data to monitor active landsliding

Science.gov (United States)

Székely, B.; Molnár, G.; Roncat, A.; Lehner, H.; Gaisecker, Th.; Drexel, P.

2009-04-01

Active slope processes often endanger various built-up objects and, as a consequence, sometimes human lives as well. Data acquision on the status and evolution of such slopes, especially those that had already affected by landsliding, therefore is a primary target for engineering geomorphic research. The method of laser scanning provides an appropriate data collection technique with the requested accuracy. Data from repeated Airborne Laser Scanning (ALS) campaigns are suitable to be analysed for the slow, incipient movements of the slope. The problem of this surveying technique is that repetition time is strongly dependent on the financial resources of the monitoring project, and often the requested recurrence of flight campaigns cannot be achieved. A possible solution to densify the data acquisition in time is the application of Terrestrial Laser Scanning (TLS) and intergration of its data with ALS data sets. TLS has the advantage of flexibility and shorter observation distances compared to ALS. This technique needs special considerations and tedious processing since the geometric setting of the data acquision considerably differ in TLS and ALS. Furthermore, obstacles in the landscape may partly hamper the data acqusition which rarely the case in ALS. Our case study area is a several-decade-long active landsliding in Doren (Federal State Vorarlberg, Austria) that as it develops, it is about to endangers houses of the locality. The site is especially suitable for the project, because multi-temporal data sets (from ALS flight campaigns in 2003, 2006 and 2007, respectively) of this area are available. The data integration is carried out in the form of production of point clouds (sensed from various points of the valley sides) and we compared the results with the results of the previous ALS campaigns. With the planned repetition of the TLS measurements new and detailed insights can be achieved concerning the evolution of the incipient and on-going slow motions. This

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 ...

Mechanism of equivalent electric dipole oscillation for high-order harmonic generation from grating-structured solid-surface by femtosecond laser pulse

Energy Technology Data Exchange (ETDEWEB)

Wang, Yang; Song, Hai-Ying; Liu, H.Y.; Liu, Shi-Bing, E-mail: sbliu@bjut.edu.cn

2017-07-12

Highlights: • Proposed a valid mechanism of high harmonic generation by laser grating target interaction: oscillation of equivalent electric dipole (OEED). • Found that there also exist harmonic emission at large emission angle but not just near-surface direction as the former researches had pointed out. • Show the process of the formation and motion of electron bunches at the grating-target surface irradiating with femtosecond laser pulse. - Abstract: We theoretically study high-order harmonic generation (HHG) from relativistically driven overdense plasma targets with rectangularly grating-structured surfaces by femtosecond laser pulses. Our particle-in-cell (PIC) simulations show that, under the conditions of low laser intensity and plasma density, the harmonics emit principally along small angles deviating from the target surface. Further investigation of the surface electron dynamics reveals that the electron bunches are formed by the interaction between the laser field and the target surface, giving rise to the oscillation of equivalent electric-dipole (OEED), which enhances specific harmonic orders. Our work helps understand the mechanism of harmonic emissions from grating targets and the distinction from the planar harmonic scheme.

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.

Investigation of the petrophysical properties of a porous sandstone sample using confocal scanning laser microscopy

Energy Technology Data Exchange (ETDEWEB)

Petford, N. [Kingston Univ., Centre for Earth and Environmental Science Research, Kingston (United Kingdom); Davidson, G. [University Coll., Dept. of Electronic and Electrical Engineering, London (United Kingdom); Miller, J.A. [Cambridge Univ., Dept. of Earth Sciences, Cambridge (United Kingdom)

2001-05-01

Confocal scanning laser microscopy (CSLM) is used to produce images of the two- and three-dimensional distribution and geometry of pore space in a reservoir sandstone and measure the 2D distribution of pore throat radii. Non-destructive serial sectioning of the rock using laser light at 100% illumination, combined with image thresholding and histogram equalization techniques allow the pore volume structure of the uppermost 100 {mu}m of the sample to be reconstructed. Negative imaging of the pore volume gave superior depth and feature resolution compared to positive (reflection) imaging. Artefacts encountered in applying classical Medial Axial Transforms to CSLM images include branch networks dominated by coordination numbers of 3. Skeletonization using Euclidean distance maps gives increased accuracy in the description of the pore network. Measured pore throat size distribution in the rock is strongly exponential and described by the expression y 219e{sup -0.25x} where y is the number of pore throats. (Author)

Fractional CO2 laser resurfacing of photoaged facial and non-facial skin: histologic and clinical results and side effects.

Science.gov (United States)

Sasaki, Gordon H; Travis, Heather M; Tucker, Barbara

2009-12-01

CO(2) fractional ablation offers the potential for facial and non-facial skin resurfacing with minimal downtime and rapid recovery. The purpose of this study was (i) to document the average depths and density of adnexal structures in non-lasered facial and non-facial body skin; (ii) to determine injury in ex vivo human thigh skin with varying fractional laser modes; and (iii) to evaluate the clinical safety and efficacy of treatments. Histologies were obtained from non-lasered facial and non-facial skin from 121 patients and from 14 samples of excised lasered thigh skin. Seventy-one patients were evaluated after varying energy (mJ) and density settings by superficial ablation, deeper penetration, and combined treatment. Skin thickness and adnexal density in non-lasered skin exhibited variable ranges: epidermis (47-105 mum); papillary dermis (61-105 mum); reticular dermis (983-1986 mum); hair follicles (2-14/ HPF); sebaceous glands (2-23/HPF); sweat glands (2-7/HPF). Histological studies of samples from human thigh skin demonstrated that increased fluencies in the superficial, deep and combined mode resulted in predictable deeper levels of ablations and thermal injury. An increase in density settings results in total ablation of the epidermis. Clinical improvement of rhytids and pigmentations in facial and non-facial skin was proportional to increasing energy and density settings. Patient assessments and clinical gradings by the Wilcoxon's test of outcomes correlated with more aggressive settings. Prior knowledge of normal skin depths and adnexal densities, as well as ex vivo skin laser-injury profiles at varying fluencies and densities, improve the safety and efficiency of fractional CO(2) for photorejuvenation of facial and non-facial skin.

Laser scanning of a recirculation zone on the Bolund escarpment

DEFF Research Database (Denmark)

Mann, Jakob; Angelou, Nikolas; Sjöholm, Mikael

2012-01-01

Rapid variations in the height of the recirculation zone are measured with a scanning wind lidar over a small escarpment on the Bolund Peninsula. The lidar is essentially a continuous-wave laser Doppler anemometer with the capability of rapidly changing the focus distance and the beam direction....... The instrument measures the line-ofsight velocity 390 times per second and scans ten wind profiles from the ground up to seven meters per second. The results will be used to test computational fluid dynamics models for flow over terrain, and has relevance for wind energy. The development of multiple lidar...

Laser scanning of a recirculation zone on the Bolund escarpment

DEFF Research Database (Denmark)

Mann, Jakob; Angelou, Nikolas; Sjöholm, Mikael

2014-01-01

Rapid variations in the height of the recirculation zone are measured with a scanning wind lidar over a small escarpment on the Bolund Peninsula. The lidar is essentially a continuous-wave laser Doppler anemometer with the capability of rapidly changing the focus distance and the beam direction....... 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...

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.

Nonlinear multicontrast microscopy of hematoxylin-and-eosin-stained histological sections

Science.gov (United States)

Tuer, Adam; Tokarz, Danielle; Prent, Nicole; Cisek, Richard; Alami, Jennifer; Dumont, Daniel J.; Bakueva, Ludmila; Rowlands, John; Barzda, Virginijus

2010-03-01

Imaging hematoxylin-and-eosin-stained cancerous histological sections with multicontrast nonlinear excitation fluorescence, second- and third-harmonic generation (THG) microscopy reveals cellular structures with extremely high image contrast. Absorption and fluorescence spectroscopy together with second hyperpolarizability measurements of the dyes shows that strong THG appears due to neutral hemalum aggregation and is subsequently enhanced by interaction with eosin. Additionally, fluorescence lifetime imaging microscopy reveals eosin fluorescence quenching by hemalums, showing better suitability of only eosin staining for fluorescence microscopy. Multicontrast nonlinear microscopy has the potential to differentiate between cancerous and healthy tissue at a single cell level.

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.

Impact of multiple sub-melt laser scans on the activation and diffusion of shallow Boron junctions

DEFF Research Database (Denmark)

Rosseel, E.; Vandervorst, W.; Clarysse, T.

2008-01-01

, careful process optimization is required. While macroscopic variations can easily be addressed using the proper spatial power compensation it is more difficult to completely eliminate the micro scale non-uniformity which is intimately linked to the laser beam profile, the amount of overlaps and the scan...... pitch. In this work, we will present micro scale sheet resistance uniformity measurements for shallow 0.5 keV B junctions and zoom in on the underlying effect of multiple subsequent laser scans. A variety of characterization techniques are used to extract the relevant junction parameters and the role...... of different implantation and anneal parameters will be explored. It turns out that the observed sheet resistance decrease with increasing number of laser scans is caused on one hand by a temperature dependent increase of the activation level, and on the other hand, by a non-negligible temperature...

Effects of target shape and reflection on laser radar cross sections.

Science.gov (United States)

Steinvall, O

2000-08-20

Laser radar cross sections have been evaluated for a number of ideal targets such as cones, spheres, paraboloids, and cylinders by use of different reflection characteristics. The time-independent cross section is the ratio of the cross section of one of these forms to that of a plate with the same maximum radius. The time-dependent laser radar cross section involves the impulse response from the object shape multiplied by the beam's transverse profile and the surface bidirectional reflection distribution function. It can be clearly seen that knowledge of the combined effect of object shape and reflection characteristics is important for determining the shape and the magnitude of the laser radar return. The results of this study are of interest for many laser radar applications such as ranging, three-dimensional imaging-modeling, tracking, antisensor lasers, and target recognition.

Flexural Behavior of Concrete Beam Strengthened by Near-Surface Mounted CFRP Reinforcement Using Equivalent Section Model

Directory of Open Access Journals (Sweden)

Woo-tai Jung

2017-01-01

Full Text Available FRP (fiber reinforced polymer has found wide applications as an alternative to steel rebar not only for the repair and strengthening of existing structures but also for the erection of new structures. Near-surface mounted (NSM strengthening was introduced as an alternative of externally bonded reinforcement (EBR but this method also experiences early bond failure, which stresses the importance of predicting accurately the bond failure behavior in order to evaluate precisely the performance of NSM reinforcement. This study proposes the equivalent section model assuming monolithic behavior of the filler and CFRP reinforcement. This equivalent section model enables establishing a bond failure model applicable independently of the sectional shape of the CFRP reinforcement. This so-derived bond failure model is then validated experimentally by means of beams flexure-strengthened by NSM CFRP reinforcements with various cross-sections. Finally, analytical analysis applying the bond failure model considering the equivalent section and defined failure criteria is performed. The results show the accuracy of the prediction of the failure mode as well as the accurate prediction of the experimental results regardless of the sectional shape of the CFRP reinforcement.

How the confocal laser scanning microscope entered biological research.

Science.gov (United States)

Amos, W B; White, J G

2003-09-01

A history of the early development of the confocal laser scanning microscope in the MRC Laboratory of Molecular Biology in Cambridge is presented. The rapid uptake of this technology is explained by the wide use of fluorescence in the 80s. The key innovations were the scanning of the light beam over the specimen rather than vice-versa and a high magnification at the level of the detector, allowing the use of a macroscopic iris. These were followed by an achromatic all-reflective relay system, a non-confocal transmission detector and novel software for control and basic image processing. This design was commercialized successfully and has been produced and developed over 17 years, surviving challenges from alternative technologies, including solid-state scanning systems. Lessons are pointed out from the unusual nature of the original funding and research environment. Attention is drawn to the slow adoption of the instrument in diagnostic medicine, despite promising applications.

Endoanal MRI of the anal sphincter complex: correlation with cross-sectional anatomy and histology

NARCIS (Netherlands)

Hussain, S. M.; Stoker, J.; Zwamborn, A. W.; den Hollander, J. C.; Kuiper, J. W.; Entius, C. A.; Laméris, J. S.

1996-01-01

The purpose of this study was to correlate the in vivo endoanal MRI findings of the anal sphincter with the cross-sectional anatomy and histology. Fourteen patients with rectal tumours were examined with a rigid endoanal MR coil before undergoing abdominoperineal resection. In addition, 12 cadavers

A novel near real-time laser scanning device for geometrical determination of pleural cavity surface.

Science.gov (United States)

Kim, Michele M; Zhu, Timothy C

2013-02-02

During HPPH-mediated pleural photodynamic therapy (PDT), it is critical to determine the anatomic geometry of the pleural surface quickly as there may be movement during treatment resulting in changes with the cavity. We have developed a laser scanning device for this purpose, which has the potential to obtain the surface geometry in real-time. A red diode laser with a holographic template to create a pattern and a camera with auto-focusing abilities are used to scan the cavity. In conjunction with a calibration with a known surface, we can use methods of triangulation to reconstruct the surface. Using a chest phantom, we are able to obtain a 360 degree scan of the interior in under 1 minute. The chest phantom scan was compared to an existing CT scan to determine its accuracy. The laser-camera separation can be determined through the calibration with 2mm accuracy. The device is best suited for environments that are on the scale of a chest cavity (between 10cm and 40cm). This technique has the potential to produce cavity geometry in real-time during treatment. This would enable PDT treatment dosage to be determined with greater accuracy. Works are ongoing to build a miniaturized device that moves the light source and camera via a fiber-optics bundle commonly used for endoscopy with increased accuracy.

Tritium Removal from JET and TFTR Tiles by a Scanning Laser

International Nuclear Information System (INIS)

Skinner, C.H.; Bekris, N.; Coad, J.P.; Gentile, C.A.; Glugla, M.

2002-01-01

Fast and efficient tritium removal is needed for future D-T machines with carbon plasma-facing components. A novel method for tritium release has been demonstrated on co-deposited layers on tiles retrieved from the Tokamak Fusion Test Reactor (TFTR) and from the Joint European Torus (JET). A scanning continuous wave neodymium laser beam was focused to =100 W/mm2 and scanned at high speed over the co-deposits, heating them to temperatures =2000 C for about 10 ms in either air or argon atmospheres. Fiber optic coupling between the laser and scanner was implemented. Up to 87% of the co-deposited tritium was thermally desorbed from the JET and TFTR samples. This technique appears to be a promising in-situ method for tritium removal in a next-step D-T device as it avoids oxidation, the associated de-conditioning of the plasma-facing surfaces, and the expense of processing large quantities of tritium oxide

Confocal laser scanning microscopy in study of bone calcification

Science.gov (United States)

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

2012-12-01

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.

Scanning mid-IR laser apparatus with eye tracking for refractive surgery

Science.gov (United States)

Telfair, William B.; Yoder, Paul R., Jr.; Bekker, Carsten; Hoffman, Hanna J.; Jensen, Eric F.

1999-06-01

A robust, real-time, dynamic eye tracker has been integrated with the short pulse mid-infrared laser scanning delivery system previously described. This system employs a Q- switched Nd:YAG laser pumped optical parametric oscillator operating at 2.94 micrometers. Previous ablation studies on human cadaver eyes and in-vivo cat eyes demonstrated very smooth ablations with extremely low damage levels similar to results with an excimer. A 4-month healing study with cats indicated no adverse healing effects. In order to treat human eyes, the tracker is required because the eyes move during the procedure due to both voluntary and involuntary motions such as breathing, heartbeat, drift, loss of fixation, saccades and microsaccades. Eye tracking techniques from the literature were compared. A limbus tracking system was best for this application. Temporal and spectral filtering techniques were implemented to reduce tracking errors, reject stray light, and increase signal to noise ratio. The expanded-capability system (IRVision AccuScan 2000 Laser System) has been tested in the lab on simulated eye targets, glass eyes, cadaver eyes, and live human subjects. Circular targets ranging from 10-mm to 14-mm diameter were successfully tracked. The tracker performed beyond expectations while the system performed myopic photorefractive keratectomy procedures on several legally blind human subjects.

In-vivo study of adhesion and bone growth around implanted laser groove/RGD-functionalized Ti-6Al-4V pins in rabbit femurs

Energy Technology Data Exchange (ETDEWEB)

Chen, J., E-mail: jianboc@gmail.com [Princeton Institute of Science and Technology of Materials and Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Bly, R.A. [Princeton Institute of Science and Technology of Materials and Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Saad, M.M.; AlKhodary, M.A.; El-Backly, R.M. [Tissue Engineering laboratories, Faculty of Dentistry, Alexandria University, Alexandria (Egypt); Cohen, D.J.; Kattamis, N. [Princeton Institute of Science and Technology of Materials and Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Fatta, M.M.; Moore, W.A. [Tissue Engineering laboratories, Faculty of Dentistry, Alexandria University, Alexandria (Egypt); Arnold, C.B. [Princeton Institute of Science and Technology of Materials and Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Marei, M.K. [Tissue Engineering laboratories, Faculty of Dentistry, Alexandria University, Alexandria (Egypt); Soboyejo, W.O. [Princeton Institute of Science and Technology of Materials and Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

2011-07-20

Titanium surfaces were designed, produced, and evaluated for levels of osseointegration into the femurs of rabbits. A total of 36 Ti-6Al-4V pins (15 mm length, 1.64 mm diameter) were prepared into three experimental groups. These were designed to test the effects of osseointegration on laser grooved, RGD coated, and polished control surfaces, as well as combined effects. Circumferential laser grooves were introduced onto pin surfaces (40 {mu}m spacing) using a UV laser ({lambda} = 355 nm). The tripeptide sequence, Arginine-Glycine-Aspartic acid (RGD), was functionalized onto laser grooved surfaces. Of the prepared samples, surface morphology and chemistry were analyzed using scanning electron microscopy (SEM) and Immunoflourescence (IF) spectroscopy, respectively. The experimental pin surfaces were surgically implanted into rabbit femurs. The samples were then harvested and evaluated histologically. Sections of the sample were preserved in a methylmethacralate mold, sliced via a hard microtome, and polished systematically. In the case of the RGD coated and laser grooved surfaces, histological results showed accelerated bone growth into the implant, pull-out tests were also used to compare the adhesion between bone and the titanium pins with/without laser textures and/or RGD coatings. - Research highlights: {yields} Circumferential laser grooves were introduced onto pin surfaces using a UV laser. {yields} The tripeptide sequence, RGD, was functionalized onto laser grooved surfaces. {yields} The experimental pin surfaces were surgically implanted into rabbit femurs. {yields} RGD coated laser groove surfaces accelerated bone growth into the implant. {yields} RGD coated laser grooved surfaces enhanced the adhesion between the bone and implant.

In-vivo study of adhesion and bone growth around implanted laser groove/RGD-functionalized Ti-6Al-4V pins in rabbit femurs

International Nuclear Information System (INIS)

Chen, J.; Bly, R.A.; Saad, M.M.; AlKhodary, M.A.; El-Backly, R.M.; Cohen, D.J.; Kattamis, N.; Fatta, M.M.; Moore, W.A.; Arnold, C.B.; Marei, M.K.; Soboyejo, W.O.

2011-01-01

Titanium surfaces were designed, produced, and evaluated for levels of osseointegration into the femurs of rabbits. A total of 36 Ti-6Al-4V pins (15 mm length, 1.64 mm diameter) were prepared into three experimental groups. These were designed to test the effects of osseointegration on laser grooved, RGD coated, and polished control surfaces, as well as combined effects. Circumferential laser grooves were introduced onto pin surfaces (40 μm spacing) using a UV laser (λ = 355 nm). The tripeptide sequence, Arginine-Glycine-Aspartic acid (RGD), was functionalized onto laser grooved surfaces. Of the prepared samples, surface morphology and chemistry were analyzed using scanning electron microscopy (SEM) and Immunoflourescence (IF) spectroscopy, respectively. The experimental pin surfaces were surgically implanted into rabbit femurs. The samples were then harvested and evaluated histologically. Sections of the sample were preserved in a methylmethacralate mold, sliced via a hard microtome, and polished systematically. In the case of the RGD coated and laser grooved surfaces, histological results showed accelerated bone growth into the implant, pull-out tests were also used to compare the adhesion between bone and the titanium pins with/without laser textures and/or RGD coatings. - Research highlights: → Circumferential laser grooves were introduced onto pin surfaces using a UV laser. → The tripeptide sequence, RGD, was functionalized onto laser grooved surfaces. → The experimental pin surfaces were surgically implanted into rabbit femurs. → RGD coated laser groove surfaces accelerated bone growth into the implant. → RGD coated laser grooved surfaces enhanced the adhesion between the bone and implant.

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)

Laser melting treatment of Ni-P surface alloys on mild steel. Influence of initial coating thickness and laser scanning rate

Directory of Open Access Journals (Sweden)

García-Alonso, M. C.

1997-08-01

Full Text Available Different thickness Ni-P coatings deposited on mild steel are submitted to laser surface melting at different scanning rates. The microstructure of the alloys is characterized by optical and scanning electron microscopy and microprobe analysis. It is shown that both the initial coating thickness and the laser scanning rate have an influence on the shape, extent and size of the different structures resulting from the solidification process. Thus, when the laser scanning rate increases a progressive refinement of the structure takes place that could even totally block the dendritic growth produced during solidification for a high initial coating thickness.

Recubrimientos de Ni-P, con distinto espesor, depositados sobre un acero microaleado fueron tratados con láser a diferentes velocidades de barrido. La microestructura, tanto del recubrimiento como del acero base, ha sido caracterizada por microscopía óptica y electrónica y por microanálisis. En el proceso de solidificación se han obtenido distintas estructuras que varían en cuanto a la forma, extensión y tamaño dependiendo del espesor inicial de recubrimiento y de la velocidad de barrido del haz láser. A medida que la velocidad del haz aumenta, se produce un refinamiento progresivo de la microestructura dendrítica y, en casos extremos de alto espesor de recubrimiento y velocidades grandes, este crecimiento dendrítico se bloquea.

Histochemical study of trans-polyisoprene accumulation by spectral confocal laser scanning microscopy and a specific dye showing fluorescence solvatochromism in the rubber-producing plant, Eucommia ulmoides Oliver.

Science.gov (United States)

Nakazawa, Yoshihisa; Takeda, Tsuyoshi; Suzuki, Nobuaki; Hayashi, Tatsushi; Harada, Yoko; Bamba, Takeshi; Kobayashi, Akio

2013-09-01

A microscopic technique combining spectral confocal laser scanning microscopy with a lipophilic fluorescent dye, Nile red, which can emit trans-polyisoprene specific fluorescence, was developed, and unmixed images of synthesized trans-polyisoprene in situ in Eucommia ulmoides were successfully obtained. The images showed that trans-polyisoprene was initially synthesized as granules in non-articulated laticifers that changed shape to fibers during laticifer maturation. Non-articulated laticifers are developed from single laticiferous cells, which are differentiated from surrounding parenchyma cells in the cambium. Therefore, these observations suggested that trans-polyisoprene biosynthesis first started in laticifer cells as granules and then the granules accumulated and fused in the inner space of the laticifers over time. Finally, laticifers were filled with the synthesized trans-polyisoprene, which formed a fibrous structure fitting the laticifers shape. Both trans- and cis-polyisoprene are among the most important polymers naturally produced by plants, and this microscopic technique combined with histological study should provide useful information in the fields of plant histology, bioindustry and phytochemistry.

Defining the Cubature Changes of Historic St. Kinga Chamber in Bochnia Salt Mine, Using Laser Scanning Technology

Directory of Open Access Journals (Sweden)

Szafarczyk Anna

2018-01-01

Full Text Available In Poland, there are many mining enterprises, of historic character registered in the UNESCO World Heritage List. One of the oldest mining enterprises in Poland is the Salt Mine in Bochnia. The processes inside the rock mass require that surveying services carry out regular geometric control of the cavities. A particular attention should be paid (due to its sacral function on St. Kinga Chamber, located 195 metres below the surface, on the mine level “August”. So far measurement technologies have been connected with the studies on changes in the geometry of cavities and based on linear bases used to measure convergence. This only provides discrete information (in a point and not always presents a real state of deformation. In the scanning method, in practice a three dimension image of changes (structural deformations is obtained, impossible to determine with the application of measurement methods, applied to measure the value of linear convergence (the method with a limited number of bases. Laser scanning, apart from determining the value of volume convergence, gives also the possibility of the visualization of 3D cavern. Moreover, it provides direct information to update mining numerical maps and make it possible to generate various cross-sections through the cavern. The authors analysed the possibility of the application of laser scanning (scanner Faro Focus 3D, as a modern tool allowing the measuring of the value of volume convergence.

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

AN AUTOMATED ROAD ROUGHNESS DETECTION FROM MOBILE LASER SCANNING DATA

Directory of Open Access Journals (Sweden)

P. Kumar

2017-05-01

Full Text Available 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.

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.

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

Not all trees sleep the same - High temporal resolution terrestrial laser scanning shows differences in nocturnal plant movement

DEFF Research Database (Denmark)

Zlinszky, András; Barfod, Anders; Molnár, Bence

2017-01-01

Circadian leaf movements are widely known in plants, but nocturnal movement of tree branches were only recently discovered by using terrestrial laser scanning (TLS), a high resolution three-dimensional surveying technique. TLS uses a pulsed laser emitted in a regular scan pattern for rapid...... surveyed a series of 18 full scans over a 12-h night period to measure nocturnal changes in shape simultaneously for an experimental setup of 22 plants representing different species. Resulting point clouds were evaluated by comparing changes in height percentiles of laser scanning points belonging...... to the canopy. Changes in crown shape were observed for all studied trees, but clearly distinguishable sleep movements are apparently rare. Ambient light conditions were continuously dark between sunset (7:30 p.m.) and sunrise (6:00 a.m.), but most changes in movement direction occurred during this period, thus...

Self-mixing laser diode included in scanning microwave microscope to the control of probe nanodisplacement

Science.gov (United States)

Usanov, D. A.; Skripal, A. V.; Astakhov, E. I.; Dobdin, S. Y.

2018-04-01

The possibilities of self-mixing interferometry for measuring nanodisplacement of a probe included in a near-field scanning microwave microscope have been considered. The features of the formation of a laser interference signal at current modulation of the wavelength of laser radiation have been investigated. Experimental responses of a semiconductor laser system included in scanning microwave microscope to control nanodisplacement of the probe have been demonstrated.To register the nanodisplacement of the probe, it is proposed to use the method of determining the stationary phase of a laser interference signal by low-frequency spectrum of a semiconductor laser. The change of the amplitudes of the spectral components in the spectrum of the interference signal due to creation of the standing wave in the external resonator of the laser self-mixing system has been shown. The form of the interference signal at current modulation of the radiation wavelength was experimentally obtained when the probe moves with a step of 80 nm. The results of measuring nanodisplacements of an electromagnetic translator STANDA 8MVT40-13 have been demonstrated. Deviation of the nanodisplacement of the proposed method does not exceed 15%.

Rapid Prototyping — A Tool for Presenting 3-Dimensional Digital Models Produced by Terrestrial Laser Scanning

Directory of Open Access Journals (Sweden)

Juho-Pekka Virtanen

2014-07-01

Full Text Available Rapid prototyping has received considerable interest with the introduction of affordable rapid prototyping machines. These machines can be used to manufacture physical models from three-dimensional digital mesh models. In this paper, we compare the results obtained with a new, affordable, rapid prototyping machine, and a traditional professional machine. Two separate data sets are used for this, both of which were acquired using terrestrial laser scanning. Both of the machines were able to produce complex and highly detailed geometries in plastic material from models based on terrestrial laser scanning. The dimensional accuracies and detail levels of the machines were comparable, and the physical artifacts caused by the fused deposition modeling (FDM technique used in the rapid prototyping machines could be found in both models. The accuracy of terrestrial laser scanning exceeded the requirements for manufacturing physical models of large statues and building segments at a 1:40 scale.

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.

MICROSTRUCTURING OF SILICON SINGLE CRYSTALS BY FIBER LASER IN HIGH-SPEED SCANNING MODE

Directory of Open Access Journals (Sweden)

T. A. Trifonova

2015-11-01

Full Text Available Subject of Study. The surface structure of the silicon wafers (substrate with a thermally grown silicon dioxide on the surface (of SiO2/Si is studied after irradiation by pulse fiber laser of ILI-1-20 type. The main requirements for exposure modes of the system are: the preservation of the integrity of the film of silicon dioxide in the process of microstructuring and the absence of interference of surrounding irradiated areas of the substrate. Method. Studies were carried out on silicon wafers KEF-4,5 oriented in the crystallographic plane (111 with the source (natural silicon dioxide (SiO2 with thickness of about 4 nm, and SiO2 with 40 nm and 150 nm thickness, grown by thermal oxidation in moist oxygen. Also, wafers KHB-10 oriented in the plane (100 with 500 nm thickness of thermal oxide were investigated. Irradiation of SiO2/Si system was produced by laser complex based on ytterbium fiber pulse laser ILI-1-20. Nominal output power of the laser was 20 W, and the laser wavelength was λ = 1062 nm. Irradiation was carried out by a focused beam spot with a diameter of 25 microns and a pulse repetition rate of 99 kHz. The samples with 150 nm and 40 nm thickness of SiO2 were irradiated at a power density equal to 1,2·102 W/cm2, and the samples of SiO2 with 500 nm thickness were irradiated at a power density equal to 2,0·102 W/cm2. Scanning was performed using a two-axis Coordinate Scanning Device based on VM2500+ drives with control via a PC with the software package "SinMarkTM." Only one scan line was used at the maximum speed of the beam equal to 8750 mm/s. Morphology control of the irradiated samples was conducted by an optical microscope ZeissA1M with high-resolution CCD array. A scanning probe microscope Nanoedicator of the NT-MDT company was used for structural measurements. Main Results. It has been shown that at a single exposure of high-frequency pulsed laser radiation on SiO2/Si system, with maintaining the integrity of the SiO2 film

Quantification of aggregate grain shape characteristics using 3-D laser scanning technology

CSIR Research Space (South Africa)

Mgangira, Martin B

2013-07-01

Full Text Available to identify the differences between individual aggregates. It was possible to quantify differences in particle shape characteristics at the small particle scale. The study has demonstrated the advantages of the innovative 3-D laser scanning technology...

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 methods towards a more accurate and automated techniques to quantify aggregate shape properties. This paper validates a new flakiness index equation using three-dimensional (3-D) laser scanning data of aggregate and ballast materials obtained from...

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

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.

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

3D camera assisted fully automated calibration of scanning laser Doppler vibrometers

Energy Technology Data Exchange (ETDEWEB)

Sels, Seppe, E-mail: Seppe.Sels@uantwerpen.be; Ribbens, Bart; Mertens, Luc; Vanlanduit, Steve [Op3Mech Research Group, University of Antwerp, Salesianenlaan 90, 2660 Antwerp (Belgium)

2016-06-28

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

Electrochemical removal of metallic implants from Technovit 9100 New embedded hard and soft tissues prior to histological sectioning.

Science.gov (United States)

Willbold, Elmar; Reebmann, Mattias; Jeffries, Richard; Witte, Frank

2013-11-01

Solid metallic implants in soft or hard tissues are serious challenges for histological processing. However, metallic implants are more frequently used in e.g. cardiovascular or orthopaedic therapies. Before clinical use, these devices need to be tested thoroughly in a biological environment and histological analysis of their biocompatibility is a major requirement. To allow the histological analysis of metallic implants in tissues especially in calcified hard tissues, we describe a method for embedding these tissues in the resin Technovit 9100 New and removing the metallic implants by electrochemical dissolution. With the combination of these two processes, we are able to achieve 5 μm thick sections from soft or hard tissues with a superior preservation of tissue architecture and especially the implant-tissue interface. These sections can be stained by classical stainings, immunohistochemical and enzymehistochemical as well as DNA-based staining methods.

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.

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

2018-03-01

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.

A pulsated weak-resonant-cavity laser diode with transient wavelength scanning and tracking for injection-locked RZ transmission.

Science.gov (United States)

Lin, Gong-Ru; Chi, Yu-Chieh; Liao, Yu-Sheng; Kuo, Hao-Chung; Liao, Zhi-Wang; Wang, Hai-Lin; Lin, Gong-Cheng

2012-06-18

By spectrally slicing a single longitudinal-mode from a master weak-resonant-cavity Fabry-Perot laser diode with transient wavelength scanning and tracking functions, the broadened self-injection-locking of a slave weak-resonant-cavity Fabry-Perot laser diode is demonstrated to achieve bi-directional transmission in a 200-GHz array-waveguide-grating channelized dense-wavelength-division-multiplexing passive optical network system. Both the down- and up-stream slave weak-resonant-cavity Fabry-Perot laser diodes are non-return-to-zero modulated below threshold and coherently injection-locked to deliver the pulsed carrier for 25-km bi-directional 2.5 Gbits/s return-to-zero transmission. The master weak-resonant-cavity Fabry-Perot laser diode is gain-switched at near threshold condition and delivers an optical coherent pulse-train with its mode linewidth broadened from 0.2 to 0.8 nm by transient wavelength scanning, which facilitates the broadband injection-locking of the slave weak-resonant-cavity Fabry-Perot laser diodes with a threshold current reducing by 10 mA. Such a transient wavelength scanning induced spectral broadening greatly releases the limitation on wavelength injection-locking range required for the slave weak-resonant-cavity Fabry-Perot laser diode. The theoretical modeling and numerical simulation on the wavelength scanning and tracking effects of the master and slave weak-resonant-cavity Fabry-Perot laser diodes are performed. The receiving power sensitivity for back-to-back transmission at bit-error-rate transmission is less than 2 dB for all 16 channels.

Novel Infiltration Diagnostics based on Laser-line Scanning and Infrared Temperature Field Imaging

Energy Technology Data Exchange (ETDEWEB)

Wang, Xinwei [Iowa State Univ., Ames, IA (United States)

2017-12-08

This project targets the building energy efficiency problems induced by building infiltration/leaks. The current infiltration inspection techniques often require extensive visual inspection and/or whole building pressure test. These current techniques cannot meet more than three of the below five criteria of ideal infiltration diagnostics: 1. location and extent diagnostics, 2. building-level application, 3. least surface preparation, 4. weather-proof, and 5. non-disruption to building occupants. These techniques are either too expensive or time consuming, and often lack accuracy and repeatability. They are hardly applicable to facades/facades section. The goal of the project was to develop a novel infiltration diagnostics technology based on laser line-scanning and simultaneous infrared temperature imaging. A laboratory scale experimental setup was designed to mimic a model house of well-defined pressure difference below or above the outside pressure. Algorithms and Matlab-based programs had been developed for recognition of the hole location in infrared images. Our experiment based on laser wavelengths of 450 and 1550 nm and laser beam diameters of 4-25 mm showed that the location of the holes could be identified using laser heating; the diagnostic approach however could not readily distinguish between infiltration and non-infiltration points. To significantly improve the scanning throughput and recognition accuracy, a second approach was explored, developed, and extensively tested. It incorporates a liquid spray on the surface to induce extra phase change cooling effect. In this spray method, we termed it as PECIT (Phase-change Enhanced Cooling Infrared Thermography), phase-change enhanced cooling was used, which significantly amplifies the effect of air flow (infiltration and exfiltration). This heat transfer method worked extremely well to identify infiltration and exfiltration locations with high accuracy and increased throughput. The PECIT technique was

Low Cost Multi-Sensor Robot Laser Scanning System and its Accuracy Investigations for Indoor Mapping Application

Science.gov (United States)

Chen, C.; Zou, X.; Tian, M.; Li, J.; Wu, W.; Song, Y.; Dai, W.; Yang, B.

2017-11-01

In order to solve the automation of 3D indoor mapping task, a low cost multi-sensor robot laser scanning system is proposed in this paper. The multiple-sensor robot laser scanning system includes a panorama camera, a laser scanner, and an inertial measurement unit and etc., which are calibrated and synchronized together to achieve simultaneously collection of 3D indoor data. Experiments are undertaken in a typical indoor scene and the data generated by the proposed system are compared with ground truth data collected by a TLS scanner showing an accuracy of 99.2% below 0.25 meter, which explains the applicability and precision of the system in indoor mapping applications.

Application of terrestrial laser scanning for measuring tree crown structures

International Nuclear Information System (INIS)

Pretzsch, H.; Seifert, S.; Huang, P.

2011-01-01

This paper addresses the potential of terrestrial laser scanning (TLS) for describing and modelling of tree crown structure and dynamics. We first present a general approach for the metabolic and structural scaling of tree crowns. Out of this approach we emphasize those normalization and scaling parameters which become accessible by TLS. For example we show how the individual tree leaf area index, convex hull, and its space-filling by leaves can be extracted out of laser scan data. This contributes to a theoretical and empirical substantiation of crown structure models which were missing so far for e.g. quantification of structural and species diversity in forest stands, inventory of crown biomass, species detection by remote sensing, and understanding of self- and alien-thinning in pure and mixed stands. Up to now works on this topic delivered a rather scattered empirical knowledge mainly by single inventories of trees and stands. In contrast, we recommend to start with a model approach, and to complete existing data with repeated TLS inventories in order to come to a consistent and theoretically based model of tree crowns. (author) [de

Cone structure imaged with adaptive optics scanning laser ophthalmoscopy in eyes with nonneovascular age-related macular degeneration.

Science.gov (United States)

Zayit-Soudry, Shiri; Duncan, Jacque L; Syed, Reema; Menghini, Moreno; Roorda, Austin J

2013-11-15

To evaluate cone spacing using adaptive optics scanning laser ophthalmoscopy (AOSLO) in eyes with nonneovascular AMD, and to correlate progression of AOSLO-derived cone measures with standard measures of macular structure. Adaptive optics scanning laser ophthalmoscopy images were obtained over 12 to 21 months from seven patients with AMD including four eyes with geographic atrophy (GA) and four eyes with drusen. Adaptive optics scanning laser ophthalmoscopy images were overlaid with color, infrared, and autofluorescence fundus photographs and spectral domain optical coherence tomography (SD-OCT) images to allow direct correlation of cone parameters with macular structure. Cone spacing was measured for each visit in selected regions including areas over drusen (n = 29), at GA margins (n = 14), and regions without drusen or GA (n = 13) and compared with normal, age-similar values. Adaptive optics scanning laser ophthalmoscopy imaging revealed continuous cone mosaics up to the GA edge and overlying drusen, although reduced cone reflectivity often resulted in hyporeflective AOSLO signals at these locations. Baseline cone spacing measures were normal in 13/13 unaffected regions, 26/28 drusen regions, and 12/14 GA margin regions. Although standard clinical measures showed progression of GA in all study eyes, cone spacing remained within normal ranges in most drusen regions and all GA margin regions. Adaptive optics scanning laser ophthalmoscopy provides adequate resolution for quantitative measurement of cone spacing at the margin of GA and over drusen in eyes with AMD. Although cone spacing was often normal at baseline and remained normal over time, these regions showed focal areas of decreased cone reflectivity. These findings may provide insight into the pathophysiology of AMD progression. (ClinicalTrials.gov number, NCT00254605).

Brief communication "Application of mobile laser scanning in snow cover profiling"

Directory of Open Access Journals (Sweden)

S. Kaasalainen

2011-03-01

Full Text Available We present a snowmobile-based mobile mapping system and its first application to snow cover roughness and change detection measurement. The ROAMER mobile mapping system, constructed at the Finnish Geodetic Institute, consists of the positioning and navigating systems, a terrestrial laser scanner, and the carrying platform (a snowmobile sledge in this application. We demonstrate the applicability of the instrument to snow cover roughness profiling and change detection by presenting preliminary results from a mobile laser scanning (MLS campaign. The results show the potential of MLS for fast and efficient snow profiling from large areas in a millimetre scale.

Infrared scanning laser ophthalmoscope imaging of the macula and its correlation with functional loss and structural changes in patients with stargardt disease.

Science.gov (United States)

Anastasakis, Anastasios; Fishman, Gerald A; Lindeman, Martin; Genead, Mohamed A; Zhou, Wensheng

2011-05-01

To correlate the degree of functional loss with structural changes in patients with Stargardt disease. Eighteen eyes of 10 patients with Stargardt disease were studied. Scanning laser ophthalmoscope infrared images were compared with corresponding spectral-domain optical coherence tomography scans. Additionally, scanning laser ophthalmoscope microperimetry was performed, and results were superimposed on scanning laser ophthalmoscope infrared images and in selected cases on fundus autofluorescence images. Seventeen of 18 eyes showed a distinct hyporeflective foveal and/or perifoveal area with distinct borders on scanning laser ophthalmoscope infrared images, which was less evident on funduscopy and incompletely depicted in fundus autofluorescence images. This hyporeflective zone corresponded to areas of significantly elevated psychophysical thresholds on microperimetry testing, in addition to thinning of the retinal pigment epithelium and disorganization or loss of the photoreceptor cell inner segment-outer segment junction and external-limiting membrane on spectral-domain optical coherence tomography. Scanning laser ophthalmoscope infrared fundus images are useful for depicting retinal structural changes in patients with Stargardt disease. A spectral-domain optical coherence tomography/scanning laser ophthalmoscope microperimetry device allows for a direct correlation of structural abnormalities with functional defects that will likely be applicable for the determination of retinal areas for potential improvement of retinal function in these patients during future clinical trials and for the monitoring of the diseases' natural history.

Comparison of 3d Reconstruction Services and Terrestrial Laser Scanning for Cultural Heritage Documentation

Science.gov (United States)

Rasztovits, S.; Dorninger, P.

2013-07-01

Terrestrial Laser Scanning (TLS) is an established method to reconstruct the geometrical surface of given objects. Current systems allow for fast and efficient determination of 3D models with high accuracy and richness in detail. Alternatively, 3D reconstruction services are using images to reconstruct the surface of an object. While the instrumental expenses for laser scanning systems are high, upcoming free software services as well as open source software packages enable the generation of 3D models using digital consumer cameras. In addition, processing TLS data still requires an experienced user while recent web-services operate completely automatically. An indisputable advantage of image based 3D modeling is its implicit capability for model texturing. However, the achievable accuracy and resolution of the 3D models is lower than those of laser scanning data. Within this contribution, we investigate the results of automated web-services for image based 3D model generation with respect to a TLS reference model. For this, a copper sculpture was acquired using a laser scanner and using image series of different digital cameras. Two different webservices, namely Arc3D and AutoDesk 123D Catch were used to process the image data. The geometric accuracy was compared for the entire model and for some highly structured details. The results are presented and interpreted based on difference models. Finally, an economical comparison of the generation of the models is given considering the interactive and processing time costs.

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.

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.

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 features...

Effect of He-Ne laser beam on the ommatidia in Schistocerca Gregaria

International Nuclear Information System (INIS)

Abd El-Meguid, A.

1996-01-01

Exposing compound eye of Schistocerca Gregaria to He-Ne laser beam affected the micro-environment of the eye. The results indicated that the ionic content (Na, K and Ca) decreased and showed measurable percentage changes about 21.3, 45.9 and 14.9% (very high significant, VHS) in the right (R); and about 32.1, 71.4 and 9.4% (VHS) in the left (L) left (L) eyes. Respectively. As compared with control (Unexposed) eyes. Also protein content showed increase in concentrations about 70.2% (VHS) and 60.0% (Hs) in both right (R) and left (L) eyes. Respectively. While albumin content showed significant (S) decrease in concentrations about 34.6 and 26.3% in both right (R) and left (L) eyes. Respectively, as compared with the control ones. Histological sections as well as scanning electron micrographs showed that exposure of eyes to laser beam affected the structure of the eyes. 4 figs., 2 tabs

Remote defect imaging for plate-like structures based on the scanning laser source technique

Science.gov (United States)

Hayashi, Takahiro; Maeda, Atsuya; Nakao, Shogo

2018-04-01

In defect imaging with a scanning laser source technique, the use of a fixed receiver realizes stable measurements of flexural waves generated by laser at multiple rastering points. This study discussed the defect imaging by remote measurements using a laser Doppler vibrometer as a receiver. Narrow-band burst waves were generated by modulating laser pulse trains of a fiber laser to enhance signal to noise ratio in frequency domain. Averaging three images obtained at three different frequencies suppressed spurious distributions due to resonance. The experimental system equipped with these newly-devised means enabled us to visualize defects and adhesive objects in plate-like structures such as a plate with complex geometries and a branch pipe.

3D laser scanning in plant and pipeline engineering; 3D-Laserscanning im Anlagen- und Rohrleitungsbau

Energy Technology Data Exchange (ETDEWEB)

Weber, T. [Kaeser und Reiner, Ingenieurbuero fuer Vermessung und Geoinformation, Fellbach (Germany)

2006-05-15

3D laser scanning has been in use for a number of years now in the fields of surveying, building and factory planning. Laser scanning can, however, provide a highly supportive and helpful tool for the plant and piping designer, too. The benefits of this technology are relevant wherever the geometry of existing systems and subsystems needs to be registered and recorded. This may be the case in planning changes (basic and detail engineering), collision checks, documentation, plant relocations and visual?display projects. (orig.)

Transverse section scanning mechanism

International Nuclear Information System (INIS)

Doherty, E.J.

1978-01-01

Apparatus is described for scanning a transverse, radionuclide scan-field using an array of focussed collimators. The collimators are movable tangentially on rails, driven by a single motor via a coupled screw. The collimators are also movable in a radial direction on rails driven by a step motor via coupled screws and bevel gears. Adjacent bevel gears rotate in opposite directions so adjacent collimators move in radially opposite directions. In use, the focal point of each collimator scans at least half of the scan-field, e.g. a human head located in the central aperture, and the electrical outputs of detectors associated with each collimator are used to determine the distribution of radioactive emission intensity at a number of points in the scan-field. (author)

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.

Correlation between ultrasound imaging, cross-sectional anatomy, and histology of the brachial plexus: a review.

Science.gov (United States)

van Geffen, Geert J; Moayeri, Nizar; Bruhn, Jörgen; Scheffer, Gert J; Chan, Vincent W; Groen, Gerbrand J

2009-01-01

The anatomy of the brachial plexus is complex. To facilitate the understanding of the ultrasound appearance of the brachial plexus, we present a review of important anatomic considerations. A detailed correlation of reconstructed, cross-sectional gross anatomy and histology with ultrasound sonoanatomy is provided.

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

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.

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

Characterisation of Intensity Values on Terrestrial Laser Scanning for Recording Enhancement

Science.gov (United States)

Balaguer-Puig, M.; Molada-Tebar, A.; Marqués-Mateu, A.; Lerma, J. L.

2017-08-01

Mapping surveys based on terrestrial laser scanning (TLS) are common nowadays for different purposes such as documentation of cultural heritage assets. The chance to extract relevant information from TLS surveys depends not only on the fast acquisition of XYZ coordinates, but also on the meaningful intensity values of the fired objects. TLS behaviour depends on several known factors such as distance, texture, roughness, colour and albedo. This paper seeks to find out the mathematical relationship between the TLS intensity values and the colorimetric data using a colour chart. In order to do so, objective colour specification based on well-known colour spaces is needed. The approach used here started with scanning a colour chart containing a number of colour patches with known chromatic and reflection characteristics. After several transformations, the results allowed us to characterise the intensity behaviour of a time-of-flight laser scanner. The characterisation of the intensity values are tested indoor on the colour chart and outdoor on an archaeological shelter. Promising results are obtained to enhance the behaviour of the intensity values coming from the TLS.

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.

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

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

Detection, mapping, and quantification of single walled carbon nanotubes in histological specimens with photoacoustic microscopy.

Science.gov (United States)

Avti, Pramod K; Hu, Song; Favazza, Christopher; Mikos, Antonios G; Jansen, John A; Shroyer, Kenneth R; Wang, Lihong V; Sitharaman, Balaji

2012-01-01

In the present study, the efficacy of multi-scale photoacoustic microscopy (PAM) was investigated to detect, map, and quantify trace amounts [nanograms (ng) to micrograms (µg)] of SWCNTs in a variety of histological tissue specimens consisting of cancer and benign tissue biopsies (histological specimens from implanted tissue engineering scaffolds). Optical-resolution (OR) and acoustic-resolution (AR)--Photoacoustic microscopy (PAM) was employed to detect, map and quantify the SWCNTs in a variety of tissue histological specimens and compared with other optical techniques (bright-field optical microscopy, Raman microscopy, near infrared (NIR) fluorescence microscopy). Both optical-resolution and acoustic-resolution PAM, allow the detection and quantification of SWCNTs in histological specimens with scalable spatial resolution and depth penetration. The noise-equivalent detection sensitivity to SWCNTs in the specimens was calculated to be as low as ∼7 pg. Image processing analysis further allowed the mapping, distribution, and quantification of the SWCNTs in the histological sections. The results demonstrate the potential of PAM as a promising imaging technique to detect, map, and quantify SWCNTs in histological specimens, and could complement the capabilities of current optical and electron microscopy techniques in the analysis of histological specimens containing SWCNTs.

Detection, mapping, and quantification of single walled carbon nanotubes in histological specimens with photoacoustic microscopy.

Directory of Open Access Journals (Sweden)

Pramod K Avti

Full Text Available In the present study, the efficacy of multi-scale photoacoustic microscopy (PAM was investigated to detect, map, and quantify trace amounts [nanograms (ng to micrograms (µg] of SWCNTs in a variety of histological tissue specimens consisting of cancer and benign tissue biopsies (histological specimens from implanted tissue engineering scaffolds.Optical-resolution (OR and acoustic-resolution (AR--Photoacoustic microscopy (PAM was employed to detect, map and quantify the SWCNTs in a variety of tissue histological specimens and compared with other optical techniques (bright-field optical microscopy, Raman microscopy, near infrared (NIR fluorescence microscopy.Both optical-resolution and acoustic-resolution PAM, allow the detection and quantification of SWCNTs in histological specimens with scalable spatial resolution and depth penetration. The noise-equivalent detection sensitivity to SWCNTs in the specimens was calculated to be as low as ∼7 pg. Image processing analysis further allowed the mapping, distribution, and quantification of the SWCNTs in the histological sections.The results demonstrate the potential of PAM as a promising imaging technique to detect, map, and quantify SWCNTs in histological specimens, and could complement the capabilities of current optical and electron microscopy techniques in the analysis of histological specimens containing SWCNTs.

The reality of virtual anthropology: Comparing digitizer and laser scan data collection methods for the quantitative assessment of the cranium.

Science.gov (United States)

Algee-Hewitt, Bridget F B; Wheat, Amber D

2016-05-01

The use of geometric morphometry to study cranial variation has steadily grown in appeal over the past decade in biological anthropology. Publication trends suggest that the most popular methods for three-dimensional data acquisition involve landmark-based coordinate data collection using a digitizer. Newer laser scan approaches are seeing increasing use, owing to the benefits that densely sampled data offer. While both of these methods have their utility, research that investigates their compatibility is lacking. The purpose of this project is to compare, quantitatively, craniometrics collected with a digitizer against data extracted from laser scans using the same individuals and laboratory conditions. Three-dimensional (x,y,z) coordinates and traditional inter-landmark distances (ILDs) were obtained with a Microscribe digitizer and 360° color models produced from NextEngine laser scans for 38 adult crania representing five cemeteries from the ADBOU skeletal collection in Denmark. Variance-based tests were performed to evaluate the disagreement between data collected with a digitizer and from laser scan models. Consideration was given to differences among landmarks by type, between ILDs calculated from landmark coordinates, and in morphology for the cemetery populations. Further, the reliability of laser scan data collection was assessed by intra-observer error tests. Researchers should be aware of the potential error associated with the use of Types II and III landmarks and the limitations on reliability imposed by object-to-scanner placement. This project reveals how laser scans can provide a valuable digital archive of cranial material that can be reasonably exploited for the "virtual" collection of coordinates and the calculation of ILDs. © 2015 Wiley Periodicals, Inc.

Distribution Analysis of the Local Critical Temperature and Current Density in YBCO Coated Conductors using Low-temperature Scanning Laser and Hall Probe Microscopy

International Nuclear Information System (INIS)

Park, S. K.; Cho, B. R.; Park, H. Y.; Ri, H. C.

2011-01-01

Distribution of the local critical temperature and current density in YBCO coated conductors were analyzed using Low-temperature Scanning Laser and Hall Probe Microscopy (LTSLHPM). We prepared YBCO coated conductors of various bridge types to study the spatial distribution of the critical temperature and the current density in single and multi bridges. LTSLHPM system was modified for detailed linescan or two-dimensional scan both scanning laser and scanning Hall probe method simultaneously. We analyzed the local critical temperature of single and multi bridges from series of several linescans of scanning laser microscopy. We also investigated local current density and hysteresis curve of single bridge from experimental results of scanning Hall probe microscopy.

Low temperature laser scanning microscopy of a superconducting radio-frequency cavity

Science.gov (United States)

Ciovati, G.; Anlage, Steven M.; Baldwin, C.; Cheng, G.; Flood, R.; Jordan, K.; Kneisel, P.; Morrone, M.; Nemes, G.; Turlington, L.; Wang, H.; Wilson, K.; Zhang, S.

2012-03-01

An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about 2.4 mm and surface resistance resolution of ˜1 μΩ at 3.3 GHz. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in detail in this contribution.

Low temperature laser scanning microscopy of a superconducting radio-frequency cavity.

Science.gov (United States)

Ciovati, G; Anlage, Steven M; Baldwin, C; Cheng, G; Flood, R; Jordan, K; Kneisel, P; Morrone, M; Nemes, G; Turlington, L; Wang, H; Wilson, K; Zhang, S

2012-03-01

An apparatus was developed to obtain, for the first time, 2D maps of the surface resistance of the inner surface of an operating superconducting radio-frequency niobium cavity by a low-temperature laser scanning microscopy technique. This allows identifying non-uniformities of the surface resistance with a spatial resolution of about 2.4 mm and surface resistance resolution of ~1 μΩ at 3.3 GHz. A signal-to-noise ratio of about 10 dB was obtained with 240 mW laser power and 1 Hz modulation frequency. The various components of the apparatus, the experimental procedure and results are discussed in detail in this contribution.

Laser scanning measurements on trees for logging harvesting operations.

Science.gov (United States)

Zheng, Yili; Liu, Jinhao; Wang, Dian; Yang, Ruixi

2012-01-01

Logging harvesters represent a set of high-performance modern forestry machinery, which can finish a series of continuous operations such as felling, delimbing, peeling, bucking and so forth with human intervention. It is found by experiment that during the process of the alignment of the harvesting head to capture the trunk, the operator needs a lot of observation, judgment and repeated operations, which lead to the time and fuel losses. In order to improve the operation efficiency and reduce the operating costs, the point clouds for standing trees are collected with a low-cost 2D laser scanner. A cluster extracting algorithm and filtering algorithm are used to classify each trunk from the point cloud. On the assumption that every cross section of the target trunk is approximate a standard circle and combining the information of an Attitude and Heading Reference System, the radii and center locations of the trunks in the scanning range are calculated by the Fletcher-Reeves conjugate gradient algorithm. The method is validated through experiments in an aspen forest, and the optimized calculation time consumption is compared with the previous work of other researchers. Moreover, the implementation of the calculation result for automotive capturing trunks by the harvesting head during the logging operation is discussed in particular.

Tritium Removal from JET and TFTR Tiles by a Scanning Laser; TOPICAL

International Nuclear Information System (INIS)

C.H. Skinner; N. Bekris; J.P. Coad; C.A. Gentile; M. Glugla

2002-01-01

Fast and efficient tritium removal is needed for future D-T machines with carbon plasma-facing components. A novel method for tritium release has been demonstrated on co-deposited layers on tiles retrieved from the Tokamak Fusion Test Reactor (TFTR) and from the Joint European Torus (JET). A scanning continuous wave neodymium laser beam was focused to=100 W/mm2 and scanned at high speed over the co-deposits, heating them to temperatures=2000 C for about 10 ms in either air or argon atmospheres. Fiber optic coupling between the laser and scanner was implemented. Up to 87% of the co-deposited tritium was thermally desorbed from the JET and TFTR samples. This technique appears to be a promising in-situ method for tritium removal in a next-step D-T device as it avoids oxidation, the associated de-conditioning of the plasma-facing surfaces, and the expense of processing large quantities of tritium oxide

Distribution and avoidance of debris on epoxy resin during UV ns-laser scanning processes

Science.gov (United States)

Veltrup, Markus; Lukasczyk, Thomas; Ihde, Jörg; Mayer, Bernd

2018-05-01

In this paper the distribution of debris generated by a nanosecond UV laser (248 nm) on epoxy resin and the prevention of the corresponding re-deposition effects by parameter selection for a ns-laser scanning process were investigated. In order to understand the mechanisms behind the debris generation, in-situ particle measurements were performed during laser treatment. These measurements enabled the determination of the ablation threshold of the epoxy resin as well as the particle density and size distribution in relation to the applied laser parameters. The experiments showed that it is possible to reduce debris on the surface with an adapted selection of pulse overlap with respect to laser fluence. A theoretical model for the parameter selection was developed and tested. Based on this model, the correct choice of laser parameters with reduced laser fluence resulted in a surface without any re-deposited micro-particles.

Combined use of fine-needle aspiration biopsy, MIBI scans and frozen section biopsy offers the best diagnostic accuracy in the assessment of the hypofunctioning solitary thyroid nodule

International Nuclear Information System (INIS)

Hurtado-Lopez, Luis Mauricio; Arellano-Montano, Sara; Torres-Acosta, Evelyn Migdalia; Zaldivar-Ramirez, Felipe Rafael; Duarte-Torres, Reyna Margarita; Alonso-de-Ruiz, Patricia; Martinez-Duncker, Ivan; Martinez-Duncker, Carlos

2004-01-01

The probability of malignancy is increased in hypofunctioning solitary thyroid nodules (HFNs). Fine-needle aspiration biopsy (FNA), 99m Tc-methoxyisobutylisonitrile (MIBI) and frozen section biopsy (FS) have limited independent diagnostic accuracy for the differential diagnosis of HFNs. The goal of this study was to assess the accuracy of the three independent diagnostic methods in distinguishing between benign and malignant disease. A total of 130 patients with an HFN on the 99m Tc-pertechnetate scan were included in this study. FNA, MIBI scans, FS, thyroidectomy and histological analysis of surgical specimens for final diagnosis were performed in all patients. Of the 130 patients, 80 (61.54%) had benign lesions and 50 (38.46%), malignant lesions. FNA was diagnostic in 78/130 (60%) patients and non-diagnostic in 52/130 (40%) patients. None of the patients with a negative MIBI scan had a final histological diagnosis of malignancy, and MIBI scans were negative in 38.46% of patients with non-diagnostic FNA results. FS was diagnostic in 104/130 (80%) patients and non-diagnostic in 26/130 (20%) patients. Sensitivity, specificity, positive and negative predictive values and positive and negative likelihood ratios were 81.3%, 97.8%, 96%, 88%, 36.95 and 0.19 respectively for FNA; 100%, 61.3%, 61.7%, 100%, 2.58 and 0 respectively for MIBI; and 80.5%, 100%, 100%, 89%, 0 and 0.2 respectively for FS. Use of both MIBI scans and FS in patients with non-diagnostic FNA rendered a specificity and sensitivity of 100%. MIBI scans exclude malignancy in a significant proportion of patients with non-diagnostic FNAs (38% in this study). Cystic nodules with a positive MIBI scan should be further investigated even when the FNA result indicates a benign lesion. Combined use of FNA, MIBI and FS offers the best diagnostic accuracy. (orig.)

A spatio-temporal index for aerial full waveform laser scanning data

Science.gov (United States)

Laefer, Debra F.; Vo, Anh-Vu; Bertolotto, Michela

2018-04-01

Aerial laser scanning is increasingly available in the full waveform version of the raw signal, which can provide greater insight into and control over the data and, thus, richer information about the scanned scenes. However, when compared to conventional discrete point storage, preserving raw waveforms leads to vastly larger and more complex data volumes. To begin addressing these challenges, this paper introduces a novel bi-level approach for storing and indexing full waveform (FWF) laser scanning data in a relational database environment, while considering both the spatial and the temporal dimensions of that data. In the storage scheme's upper level, the full waveform datasets are partitioned into spatial and temporal coherent groups that are indexed by a two-dimensional R∗-tree. To further accelerate intra-block data retrieval, at the lower level a three-dimensional local octree is created for each pulse block. The local octrees are implemented in-memory and can be efficiently written to a database for reuse. The indexing solution enables scalable and efficient three-dimensional (3D) spatial and spatio-temporal queries on the actual pulse data - functionalities not available in other systems. The proposed FWF laser scanning data solution is capable of managing multiple FWF datasets derived from large flight missions. The flight structure is embedded into the data storage model and can be used for querying predicates. Such functionality is important to FWF data exploration since aircraft locations and orientations are frequently required for FWF data analyses. Empirical tests on real datasets of up to 1 billion pulses from Dublin, Ireland prove the almost perfect scalability of the system. The use of the local 3D octree in the indexing structure accelerated pulse clipping by 1.2-3.5 times for non-axis-aligned (NAA) polyhedron shaped clipping windows, while axis-aligned (AA) polyhedron clipping was better served using only the top indexing layer. The distinct

Improved resolution by mounting of tissue sections for laser microdissection.

Science.gov (United States)

van Dijk, M C R F; Rombout, P D M; Dijkman, H B P M; Ruiter, D J; Bernsen, M R

2003-08-01

Laser microbeam microdissection has greatly facilitated the procurement of specific cell populations from tissue sections. However, the fact that a coverslip is not used means that the morphology of the tissue sections is often poor. To develop a mounting method that greatly improves the morphological quality of tissue sections for laser microbeam microdissection purposes so that the identification of target cells can be facilitated. Fresh frozen tissue and formalin fixed, paraffin wax embedded tissue specimens were used to test the morphological quality of mounted and unmounted tissue. The mounting solution consisted of an adhesive gum and blue ink diluted in water. Interference of the mounting solution with DNA quality was analysed by the polymerase chain reaction using 10-2000 cells isolated by microdissection from mounted and unmounted tissue. The mounting solution greatly improved the morphology of tissue sections for laser microdissection purposes and had no detrimental effects on the isolation and efficiency of amplification of DNA. One disadvantage was that the mounting solution reduced the cutting efficiency of the ultraviolet laser. To minimise this effect, the mounting solution should be diluted as much as possible. Furthermore, the addition of blue ink to the mounting medium restores the cutting efficiency of the laser. The mounting solution is easy to prepare and apply and can be combined with various staining methods without compromising the quality of the DNA extracted.

Multimodal backside imaging of a microcontroller using confocal laser scanning and optical-beam-induced current imaging

Science.gov (United States)

Finkeldey, Markus; Göring, Lena; Schellenberg, Falk; Brenner, Carsten; Gerhardt, Nils C.; Hofmann, Martin

2017-02-01

Microscopy imaging with a single technology is usually restricted to a single contrast mechanism. Multimodal imaging is a promising technique to improve the structural information that could be obtained about a device under test (DUT). Due to the different contrast mechanisms of laser scanning microscopy (LSM), confocal laser scanning microscopy (CLSM) and optical beam induced current microscopy (OBICM), a combination could improve the detection of structures in integrated circuits (ICs) and helps to reveal their layout. While OBIC imaging is sensitive to the changes between differently doped areas and to semiconductor-metal transitions, CLSM imaging is mostly sensitive to changes in absorption and reflection. In this work we present the implementation of OBIC imaging into a CLSM. We show first results using industry standard Atmel microcontrollers (MCUs) with a feature size of about 250nm as DUTs. Analyzing these types of microcontrollers helps to improve in the field of side-channel attacks to find hardware Trojans, possible spots for laser fault attacks and for reverse engineering. For the experimental results the DUT is placed on a custom circuit board that allows us to measure the current while imaging it in our in-house built stage scanning microscope using a near infrared (NIR) laser diode as light source. The DUT is thinned and polished, allowing backside imaging through the Si-substrate. We demonstrate the possibilities using this optical setup by evaluating OBIC, LSM and CLSM images above and below the threshold of the laser source.

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

3-D reconstruction of neurons from multichannel confocal laser scanning image series.

Science.gov (United States)

Wouterlood, Floris G

2014-04-10

A confocal laser scanning microscope (CLSM) collects information from a thin, focal plane and ignores out-of-focus information. Scanning of a specimen, with stepwise axial (Z-) movement of the stage in between each scan, produces Z-series of confocal images of a tissue volume, which then can be used to 3-D reconstruct structures of interest. The operator first configures separate channels (e.g., laser, filters, and detector settings) for each applied fluorochrome and then acquires Z-series of confocal images: one series per channel. Channel signal separation is extremely important. Measures to avoid bleaching are vital. Post-acquisition deconvolution of the image series is often performed to increase resolution before 3-D reconstruction takes place. In the 3-D reconstruction programs described in this unit, reconstructions can be inspected in real time from any viewing angle. By altering viewing angles and by switching channels off and on, the spatial relationships of 3-D-reconstructed structures with respect to structures visualized in other channels can be studied. Since each brand of CLSM, computer program, and 3-D reconstruction package has its own proprietary set of procedures, a general approach is provided in this protocol wherever possible. Copyright © 2014 John Wiley & Sons, Inc.

Non-Linear Structural Dynamics Characterization using a Scanning Laser Vibrometer

Science.gov (United States)

Pai, P. F.; Lee, S.-Y.

2003-01-01

This paper presents the use of a scanning laser vibrometer and a signal decomposition method to characterize non-linear dynamics of highly flexible structures. A Polytec PI PSV-200 scanning laser vibrometer is used to measure transverse velocities of points on a structure subjected to a harmonic excitation. Velocity profiles at different times are constructed using the measured velocities, and then each velocity profile is decomposed using the first four linear mode shapes and a least-squares curve-fitting method. From the variations of the obtained modal \\ielocities with time we search for possible non-linear phenomena. A cantilevered titanium alloy beam subjected to harmonic base-excitations around the second. third, and fourth natural frequencies are examined in detail. Influences of the fixture mass. gravity. mass centers of mode shapes. and non-linearities are evaluated. Geometrically exact equations governing the planar, harmonic large-amplitude vibrations of beams are solved for operational deflection shapes using the multiple shooting method. Experimental results show the existence of 1:3 and 1:2:3 external and internal resonances. energy transfer from high-frequency modes to the first mode. and amplitude- and phase- modulation among several modes. Moreover, the existence of non-linear normal modes is found to be questionable.

Pedestrian Detection by Laser Scanning and Depth Imagery

Science.gov (United States)

Barsi, A.; Lovas, T.; Molnar, B.; Somogyi, A.; Igazvolgyi, Z.

2016-06-01

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).

Spatially resolved analyses of uranium species using a coupled system made up of confocal laser-scanning microscopy (CLSM) and laser induced fluorescence spectroscopy (LIFS); Ortsaufgeloeste Analyse von Uranspezies mittels einem Gekoppelten System aus Konfokaler Laser-Scanning Mikroskopie (CLSM) und Laser Induzierter Fluoreszenzspektroskopie (LIFS)

Energy Technology Data Exchange (ETDEWEB)

Brockmann, S. [Verein fuer Kernverfahrenstechnik und Analytik Rossendorf e.V. (VKTA), Dresden (Germany); Grossmann, K.; Arnold, T. [Helmholtz-Zentrum Dresden-Rossendorf e.V. (Germany). Inst. fuer Ressourcenoekologie

2014-01-15

The fluorescent properties of uranium when excited by UV light are used increasingly for spectroscope analyses of uranium species within watery samples. Here, alongside the fluorescent properties of the hexavalent oxidation phases, the tetra and pentavalent oxidation phases also play an increasingly important role. The detection of fluorescent emission spectrums on solid and biological samples using (time-resolved) laser induced fluorescence spectroscopy (TRLFS or LIFS respectively) has, however, the disadvantage that no statements regarding the spatial localisation of the uranium can be made. However, particularly in complex, biological samples, such statements on the localisation of the uranium enrichment in the sample are desired, in order to e.g. be able to distinguish between intra and extra-cellular uranium bonds. The fluorescent properties of uranium (VI) compounds and minerals can also be used to detect their localisation within complex samples. So the application of fluorescent microscopic methods represents one possibility to localise and visualise uranium precipitates and enrichments in biological samples, such as biofilms or cells. The confocal laser-scanning microscopy (CLSM) is especially well suited to this purpose. Coupling confocal laser-scanning microscopy (CLSM) with laser induced fluorescence spectroscopy (LIFS) makes it possible to localise and visualise fluorescent signals spatially and three-dimensionally, while at the same time being able to detect spatially resolved, fluorescent-spectroscopic data. This technology is characterised by relatively low detection limits from up to 1.10{sup -6} M for uranium (VI) compounds within the confocal volume. (orig.)

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

Musculature of Notholca acuminata (Rotifera : Ploima : Brachionidae) revealed by confocal scanning laser microscopy

DEFF Research Database (Denmark)

Sørensen, M.V.; Funch, P.; Hooge, M.

2003-01-01

The body-wall and visceral musculature of Notholca acuminata was visualized using phalloidin-linked fluorescent dye under confocal laser scanning microscopy. The body-wall musculature includes dorsal, lateral, and ventral pairs of longitudinally oriented body retractor muscles, two pairs of head...

Two-photon excitation laser scanning microscopy of rabbit nasal septal cartilage following Nd:YAG-laser-mediated stress relaxation

Science.gov (United States)

Kim, Charlton C.; Wallace, Vincent P.; Coleno, Mariah L.; Dao, Xavier; Tromberg, Bruce J.; Wong, Brian J.

2000-04-01

Laser irradiation of hyaline cartilage result in stable shape changes due to temperature dependent stress relaxation. In this study, we determined the structural changes in chondrocytes within rabbit nasal septal cartilage tissue over a 12-day period using a two-photon laser scanning microscope (TPM) following Nd:YAG laser irradiation. During laser irradiation surface temperature, stress relaxation, and diffuse reflectance, were measured dynamically. Each specimen received one or two sequential laser exposures. The cartilage reached a peak surface temperature of about 61 degrees C during irradiation. Cartilage denatured in 50 percent EtOH was used as a positive control. TPM was performed to detect the fluorescence emission from the chondrocytes. Images of chondrocytes were obtained at depths up to 150 microns, immediately following laser exposure, and also following 12 days in culture. Few differences in the pattern or intensity of fluorescence was observed between controls and irradiated specimens imaged immediately following exposure, regardless of the number of laser pulses. However, following twelve days in tissue culture, the irradiated specimens increase, whereas the native tissue diminishes, in intensity and distribution of fluorescence in the cytoplasm. In contrast, the positive control shows only extracellular matrices and empty lacuna, feature consistent with cell membrane lysis.

Design-based stereological estimation of the total number of cardiac myocytes in histological sections

DEFF Research Database (Denmark)

Brüel, Annemarie; Nyengaard, Jens Randel

2005-01-01

in LM sections using design-based stereology. MATERIALS AND METHODS: From formalin-fixed left rat ventricles (LV) isotropic uniformly random sections were cut. The total number of myocyte nuclei per LV was estimated using the optical disector. Two-microm-thick serial paraffin sections were stained......BACKGROUND: Counting the total number of cardiac myocytes has not previously been possible in ordinary histological sections using light microscopy (LM) due to difficulties in defining the myocyte borders properly. AIM: To describe a method by which the total number of cardiac myocytes is estimated...... with antibodies against cadherin and type IV collagen to visualise the intercalated discs and the myocyte membranes, respectively. Using the physical disector in "local vertical windows" of the serial sections, the average number of nuclei per myocyte was estimated.RESULTS: The total number of myocyte nuclei...

Sensor-Topology Based Simplicial Complex Reconstruction from Mobile Laser Scanning

Science.gov (United States)

Guinard, S.; Vallet, B.

2018-05-01

We propose a new method for the reconstruction of simplicial complexes (combining points, edges and triangles) from 3D point clouds from Mobile Laser Scanning (MLS). Our main goal is to produce a reconstruction of a scene that is adapted to the local geometry of objects. Our method uses the inherent topology of the MLS sensor to define a spatial adjacency relationship between points. We then investigate each possible connexion between adjacent points and filter them by searching collinear structures in the scene, or structures perpendicular to the laser beams. Next, we create triangles for each triplet of self-connected edges. Last, we improve this method with a regularization based on the co-planarity of triangles and collinearity of remaining edges. We compare our results to a naive simplicial complexes reconstruction based on edge length.

Special Section on Fusion Laser Engineering

International Nuclear Information System (INIS)

Murray, J. R.; Soures, J. M.

2004-01-01

The National Ignition Facility (NIF) now under construction at Lawrence Livermore National Laboratory contains a large frequency-tripled neodymium glass laser system designed to deliver approximately 2 megajoules of ultraviolet laser light in nanosecond pulses to targets for the study of high-energy-density physics and inertial confinement fusion. When all 192 laser beams are operational in 2008 it will dwarf any currently operating laser system, and even with only four beams now operating it is among the largest and most energetic of such systems. This special section is a collection of papers covering important issues in the optical engineering of large lasers such as NIF. A number of other papers on NIF engineering issues can be found in the Proceedings of SPIE, volume 5341. The first paper by Miller, Moses, and Wuest is an overview of the NIF project and the applications for which the facility was designed. The following papers discuss specific issues in greater depth. Spaeth, et al., discuss the NIF laser architecture, the effect of optical performance specifications on the focal spot size, and some aspects of cleanliness in large laser systems. Bonnano discusses the strategy for assembling NIF from ''line-replaceable units'' (LRU) that are assembled in a cleanroom and transported to the laser system in sealed containers that mate with the laser enclosures and allow clean installations without maintaining cleanroom standards throughout the facility. Zacharias, et al., discuss the alignment and wavefront control systems that allow beams to strike the target within ±50 microns after a beam path of about 350 meters. Shaw, et al., discuss a laser performance operations model that is used to set up the laser for a shot, and compare the predictions of the model to data from the first four operating beams. Ermolaeva, et al. discuss the design and performance of a custom optical fiber that was developed for use in NIF ultraviolet diagnostics. Finally, Honig discusses

Registration area and accuracy when integrating laser-scanned and maxillofacial cone-beam computed tomography images.

Science.gov (United States)

Sun, LiJun; Hwang, Hyeon-Shik; Lee, Kyung-Min

2018-03-01

The purpose of this study was to examine changes in registration accuracy after including occlusal surface and incisal edge areas in addition to the buccal surface when integrating laser-scanned and maxillofacial cone-beam computed tomography (CBCT) dental images. CBCT scans and maxillary dental casts were obtained from 30 patients. Three methods were used to integrate the images: R1, only the buccal and labial surfaces were used; R2, the incisal edges of the anterior teeth and the buccal and distal marginal ridges of the second molars were used; and R3, labial surfaces, including incisal edges of anterior teeth, and buccal surfaces, including buccal and distal marginal ridges of the second molars, were used. Differences between the 2 images were evaluated by color-mapping methods and average surface distances by measuring the 3-dimensional Euclidean distances between the surface points on the 2 images. The R1 method showed more discrepancies between the laser-scanned and CBCT images than did the other methods. The R2 method did not show a significant difference in registration accuracy compared with the R3 method. The results of this study indicate that accuracy when integrating laser-scanned dental images into maxillofacial CBCT images can be increased by including occlusal surface and incisal edge areas as registration areas. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Laser scanning cytometry (LCS) allows detailed analysis of the cell cycle in PI stained human fibroblasts (TIG-7).

Science.gov (United States)

Kawasaki, M; Sasaki, K; Satoh, T; Kurose, A; Kamada, T; Furuya, T; Murakami, T; Todoroki, T

1997-01-01

We have demonstrated a method for the in situ determination of the cell cycle phases of TIG-7 fibroblasts using a laser scanning cytometer (LSC) which has not only a function equivalent to flow cytometry (FCM) but also has a capability unique in itself. LSC allows a more detailed analysis of the cell cycle in cells stained with propidium iodide (PI) than FCM. With LSC it is possible to discriminate between mitotic cells and G2 cells, between post-mitotic cells and G1 cells, and between quiescent cells and cycling cells in a PI fluorescence peak (chromatin condensation) vs. fluorescence value (DNA content) cytogram for cells stained with PI. These were amply confirmed by experiments using colcemid and adriamycin. We were able to identify at least six cell subpopulations for PI stained cells using LSC; namely G1, S, G2, M, postmitotic and quiescent cell populations. LSC analysis facilitates the monitoring of effects of drugs on the cell cycle.

The Development of a Virtual 3D Model of the Renal Corpuscle from Serial Histological Sections for E-Learning Environments

Science.gov (United States)

Roth, Jeremy A.; Wilson, Timothy D.; Sandig, Martin

2015-01-01

Histology is a core subject in the anatomical sciences where learners are challenged to interpret two-dimensional (2D) information (gained from histological sections) to extrapolate and understand the three-dimensional (3D) morphology of cells, tissues, and organs. In gross anatomical education 3D models and learning tools have been associated…

Automatic Stem Mapping by Merging Several Terrestrial Laser Scans at the Feature and Decision Levels

Directory of Open Access Journals (Sweden)

Juha Hyyppä

2013-01-01

Full Text Available Detailed up-to-date ground reference data have become increasingly important in quantitative forest inventories. Field reference data are conventionally collected at the sample plot level by means of manual measurements, which are both labor-intensive and time-consuming. In addition, the number of attributes collected from the tree stem is limited. More recently, terrestrial laser scanning (TLS, using both single-scan and multi-scan techniques, has proven to be a promising solution for efficient stem mapping at the plot level. In the single-scan method, the laser scanner is placed at the center of the plot, creating only one scan, and all trees are mapped from the single-scan point cloud. Consequently, the occlusion of stems increases as the range of the scanner increases, depending on the forest’s attributes. In the conventional multi-scan method, several scans are made simultaneously inside and outside of the plot to collect point clouds representing all trees within the plot, and these scans are accurately co-registered by using artificial reference targets manually placed throughout the plot. The additional difficulty of applying the multi-scan method is due to the point-cloud registration of several scans not being fully automated yet. This paper proposes a multi-single-scan (MSS method to map the sample plot. The method does not require artificial reference targets placed on the plot or point-level registration. The MSS method is based on the fully automated processing of each scan independently and on the merging of the stem positions automatically detected from multiple scans to accurately map the sample plot. The proposed MSS method was tested on five dense forest plots. The results show that the MSS method significantly improves the stem-detection accuracy compared with the single-scan approach and achieves a mapping accuracy similar to that achieved with the multi-scan method, without the need for the point-level registration.

Histological observation on dental hard tissue irradiated by ultrashort-pulsed laser

Science.gov (United States)

Uchizono, Takeyuki; Awazu, Kunio; Igarashi, Akihiro; Kato, Junji; Hirai, Yoshito

2006-04-01

In the field of dentistry, effectiveness of USPL irradiation is researched because USPL has less thermal side effect to dental hard tissue. In this paper, we observed morphological change and optical change of dental hard tissue irradiated by USPL for discussing the safety and effectiveness of USPL irradiation to dental hard tissues. Irradiated samples were crown enamel and root dentin of bovine teeth. Lasers were Ti:sapphire laser, which had pulse duration (P d)of 130 fsec and pulse repetition rate (f) of 1kHz and wavelength (l) of 800nm, free electron laser (FEL), which had P d of 15 μsec and f of 10Hz and wavelength of 9.6μm, and Er:YAG laser, which had P d of 250 μsec and f of 10Hz and wavelength of 2.94μm. After laser irradiation, the sample surfaces and cross sections were examined with SEM and EDX. The optical change of samples was observed using FTIR. In SEM, the samples irradiated by USPL had sharp and accurate ablation with no crack and no carbonization. But, in FEL and Er:YAG laser, the samples has rough ablation with crack and carbonization. It was cleared that the P/Ca ratio of samples irradiated by USPL had same value as non-irradiated samples. There was no change in the IR absorption spectrum between samples irradiated by USPL and non-irradiated sample. But, they of samples irradiated by FEL and Er:YAG laser, however, had difference value as non-irradiated samples. These results showed that USPL might be effective to ablate dental hard tissue without thermal damage.

Transient gels in colloid-polymer mixtures studied with fluorescence confocal scanning laser microscopy

NARCIS (Netherlands)

Verhaegh, N.A.M.; Asnaghi, D.; Lekkerkerker, H.N.W.

1999-01-01

We study the structure and the time evolution of transient gels formed in colloid-polymer mixtures, by means of uorescence Confocal Scanning Laser Microscopy (CSLM). This technique is used in conjunction with novel colloidal silica particles containing a uorescent core. The confocal micrographs

Application of laser scan microscopy in vivo for wound healing characterization

International Nuclear Information System (INIS)

Czaika, V; Koch, S; Alborova, A; Sterry, W; Lademann, J

2010-01-01

Considering the advancing age of the population, wound healing disturbances are becoming increasingly important in clinical routine. The development of wound healing creams and lotions as well as therapy control require an objective evaluation of the wound healing process, which represents the destruction of the barrier. Therefore, transepidermal water loss measurements are often carried out. These measurements have the disadvantage that they are disturbed by the interstitial fluid, which is located on the surface of chronic wounds and also by water components of the creams and lotions. Additionally, the TEWL measurements are very sensitive to temperature changes and to the anxiety of the volunteers. In the present study, in vivo laser scanning microscopy was used to analyze the reepithelialization and barrier recovery of standardized wounds produced by the suction blister technique. It was demonstrated that this non-invasive, on-line spectroscopic method allows the evaluation of the wound healing process, without any disturbances. It was found that the wound healing starts not only from the edges of the wound, but also out of the hair follicles. The in vivo laser scanning microscopy is well suited to evaluate the efficacy of wound healing creams and for therapy control

Application of laser scan microscopy in vivo for wound healing characterization

Science.gov (United States)

Czaika, V.; Alborova, A.; Sterry, W.; Lademann, J.; Koch, S.

2010-09-01

Considering the advancing age of the population, wound healing disturbances are becoming increasingly important in clinical routine. The development of wound healing creams and lotions as well as therapy control require an objective evaluation of the wound healing process, which represents the destruction of the barrier. Therefore, transepidermal water loss measurements are often carried out. These measurements have the disadvantage that they are disturbed by the interstitial fluid, which is located on the surface of chronic wounds and also by water components of the creams and lotions. Additionally, the TEWL measurements are very sensitive to temperature changes and to the anxiety of the volunteers. In the present study, in vivo laser scanning microscopy was used to analyze the reepithelialization and barrier recovery of standardized wounds produced by the suction blister technique. It was demonstrated that this non-invasive, on-line spectroscopic method allows the evaluation of the wound healing process, without any disturbances. It was found that the wound healing starts not only from the edges of the wound, but also out of the hair follicles. The in vivo laser scanning microscopy is well suited to evaluate the efficacy of wound healing creams and for therapy control.

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.

Gallium scans in myasthenia gravis

International Nuclear Information System (INIS)

Swick, H.M.; Preston, D.F.; McQuillen, M.P.

1976-01-01

A study was conducted to determine whether 67 Ga scans could be used for the detection of thymomas and to investigate the activity of the thymus gland in patients with myasthenia gravis. Scans of the anterior mediastinum proved to be a reliable way to detect thymomas. The scans were positive in eight patients including three with myasthenia gravis and histologically proved thymomas, three others with severe myasthenia gravis and thymic tumors, and two with histologically proved thymomas not associated with myasthenia. Activity on 67 Ga scans was not directly related to the increased activity of the thymus gland that is presumed to be associated with myasthenia gravis

Gallium scans in myasthenia gravis

Energy Technology Data Exchange (ETDEWEB)

Swick, H.M. (Univ. of Kentucky, Lexington); Preston, D.F.; McQuillen, M.P.

1976-01-01

A study was conducted to determine whether /sup 67/Ga scans could be used for the detection of thymomas and to investigate the activity of the thymus gland in patients with myasthenia gravis. Scans of the anterior mediastinum proved to be a reliable way to detect thymomas. The scans were positive in eight patients including three with myasthenia gravis and histologically proved thymomas, three others with severe myasthenia gravis and thymic tumors, and two with histologically proved thymomas not associated with myasthenia. Activity on /sup 67/Ga scans was not directly related to the increased activity of the thymus gland that is presumed to be associated with myasthenia gravis. (HLW)

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.

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.

Scanning laser densitometry and color perimetry demonstrate reduced photopigment density and sensitivity in two patients with retinal degeneration.

Science.gov (United States)

Tornow, R P; Stilling, R; Zrenner, E

1999-10-01

To test the feasibility of scanning laser densitometry with a modified Rodenstock scanning laser ophthalmoscope (SLO) to measure the rod and cone photopigment distribution in patients with retinal diseases. Scanning laser densitometry was performed using a modified Rodenstock scanning laser ophthalmoscope. The distribution of the photopigments was calculated from dark adapted and bleached images taken with the 514 nm laser of the SLO. This wavelength is absorbed by rod and cone photopigments. Discrimination is possible due to their different spatial distribution. Additionally, to measure retinal sensitivity profiles, dark adapted two color static perimetry with a Tübinger manual perimeter was performed along the horizontal meridian with 1 degree spacing. A patient with retinitis pigmentosa had slightly reduced photopigment density within the central +/- 5 degrees but no detectable photopigment for eccentricities beyond 5 degrees. A patient with cone dystrophy had nearly normal pigment density beyond +/- 5 degrees, but considerably reduced photopigment density within the central +/- 5 degrees. Within the central +/- 5 degrees, the patient with retinitis pigmentosa had normal sensitivity for the red stimulus and reduced sensitivity for the green stimulus. There was no measurable function beyond 7 degrees. The patient with cone dystrophy had normal sensitivity for the green stimulus outside the foveal center and reduced sensitivity for the red stimulus at the foveal center. The results of color perimetry for this patient with a central scotoma were probably influenced by eccentric fixation. Scanning laser densitometry with a modified Rodenstock SLO is a useful method to assess the human photopigment distribution. Densitometry results were confirmed by dark adapted two color static perimetry. Photopigment distribution and retinal sensitivity profiles can be measured with high spatial resolution. This may help to measure exactly the temporal development of retinal

μCT of ex-vivo stained mouse hearts and embryos enables a precise match between 3D virtual histology, classical histology and immunochemistry

Science.gov (United States)

Larsson, Emanuel; Martin, Sabine; Lazzarini, Marcio; Tromba, Giuliana; Missbach-Guentner, Jeannine; Pinkert-Leetsch, Diana; Katschinski, Dörthe M.; Alves, Frauke

2017-01-01

The small size of the adult and developing mouse heart poses a great challenge for imaging in preclinical research. The aim of the study was to establish a phosphotungstic acid (PTA) ex-vivo staining approach that efficiently enhances the x-ray attenuation of soft-tissue to allow high resolution 3D visualization of mouse hearts by synchrotron radiation based μCT (SRμCT) and classical μCT. We demonstrate that SRμCT of PTA stained mouse hearts ex-vivo allows imaging of the cardiac atrium, ventricles, myocardium especially its fibre structure and vessel walls in great detail and furthermore enables the depiction of growth and anatomical changes during distinct developmental stages of hearts in mouse embryos. Our x-ray based virtual histology approach is not limited to SRμCT as it does not require monochromatic and/or coherent x-ray sources and even more importantly can be combined with conventional histological procedures. Furthermore, it permits volumetric measurements as we show for the assessment of the plaque volumes in the aortic valve region of mice from an ApoE-/- mouse model. Subsequent, Masson-Goldner trichrome staining of paraffin sections of PTA stained samples revealed intact collagen and muscle fibres and positive staining of CD31 on endothelial cells by immunohistochemistry illustrates that our approach does not prevent immunochemistry analysis. The feasibility to scan hearts already embedded in paraffin ensured a 100% correlation between virtual cut sections of the CT data sets and histological heart sections of the same sample and may allow in future guiding the cutting process to specific regions of interest. In summary, since our CT based virtual histology approach is a powerful tool for the 3D depiction of morphological alterations in hearts and embryos in high resolution and can be combined with classical histological analysis it may be used in preclinical research to unravel structural alterations of various heart diseases. PMID:28178293

2-photon laser scanning microscopy on native human cartilage

Science.gov (United States)

Martini, Joerg; Toensing, Katja; Dickob, Michael; Anselmetti, Dario

2005-08-01

Native hyaline cartilage from a human knee joint was directly investigated with laser scanning microscopy via 2-photon autofluorescence excitation with no additional staining or labelling protocols in a nondestructive and sterile manner. Using a femtosecond, near-infrared (NIR) Ti:Sa laser for 2-photon excitation and a dedicated NIR long distance objective, autofluorescence imaging and measurements of the extracellular matrix (ECM) tissue with incorporated chondrocytes were possible with a penetration depth of up to 460 μm inside the sample. Via spectral autofluorescence separation these experiments allowed the discrimination of chondrocytes from the ECM and therefore an estimate of chondrocytic cell density within the cartilage tissue to approximately 0.2-2•107cm3. Furthermore, a comparison of the relative autofluorescence signals between nonarthritic and arthritic cartilage tissue exhibited distinct differences in tissue morphology. As these morphological findings are in keeping with the macroscopic diagnosis, our measurement has the potential of being used in future diagnostic applications.

Effects of Laser Operating Parameters on Piezoelectric Substrates Micromachining with Picosecond Laser

Directory of Open Access Journals (Sweden)

Lamia EL Fissi

2014-12-01

Full Text Available Ten picoseconds (200 kHz ultrafast laser micro-structuring of piezoelectric substrates including AT-cut quartz, Lithium Niobate and Lithium Tantalate have been studied for the purpose of piezoelectric devices application ranging from surface acoustic wave devices, e.g., bandpass filters, to photonic devices such as optical waveguides and holograms. The study examines the impact of changing several laser parameters on the resulting microstructural shapes and morphology. The micromachining rate has been observed to be strongly dependent on the operating parameters, such as the pulse fluence, the scan speed and the scan number. The results specifically indicate that ablation at low fluence and low speed scan tends to form a U-shaped cross-section, while a V-shaped profile can be obtained by using a high fluence and a high scan speed. The evolution of surface morphology revealed that laser pulses overlap in a range around 93% for both Lithium Niobate (LiNbO3 and Lithium Tantalate (LiTaO3 and 98% for AT-cut quartz can help to achieve optimal residual surface roughness.

A simple but precise method for quantitative measurement of the quality of the laser focus in a scanning optical microscope.

Science.gov (United States)

Trägårdh, J; Macrae, K; Travis, C; Amor, R; Norris, G; Wilson, S H; Oppo, G-L; McConnell, G

2015-07-01

We report a method for characterizing the focussing laser beam exiting the objective in a laser scanning microscope. This method provides the size of the optical focus, the divergence of the beam, the ellipticity and the astigmatism. We use a microscopic-scale knife edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide, and a light-collecting optical fibre and photodiode underneath the specimen. By scanning the laser spot from a reflective to a transmitting part of the grid, a beam profile in the form of an error function can be obtained and by repeating this with the knife edge at different axial positions relative to the beam waist, the divergence and astigmatism of the postobjective laser beam can be obtained. The measured divergence can be used to quantify how much of the full numerical aperture of the lens is used in practice. We present data of the beam radius, beam divergence, ellipticity and astigmatism obtained with low (0.15, 0.7) and high (1.3) numerical aperture lenses and lasers commonly used in confocal and multiphoton laser scanning microscopy. Our knife-edge method has several advantages over alternative knife-edge methods used in microscopy including that the knife edge is easy to prepare, that the beam can be characterized also directly under a cover slip, as necessary to reduce spherical aberrations for objectives designed to be used with a cover slip, and it is suitable for use with commercial laser scanning microscopes where access to the laser beam can be limited. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

Validation of a new noniterative method for accurate position determination of a scanning laser vibrometer

Science.gov (United States)

Pauwels, Steven; Boucart, Nick; Dierckx, Benoit; Van Vlierberghe, Pieter

2000-05-01

The use of a scanning laser Doppler vibrometer for vibration testing is becoming a popular instrument. The scanning laser Doppler vibrometer is a non-contacting transducer that can measure many points at a high spatial resolution in a short time. Manually aiming the laser beam at the points that need to be measured is very time consuming. In order to use it effectively, the position of the laser Doppler vibrometer needs to be determined relative to the structure. If the position of the laser Doppler vibrometer is known, any visible point on the structure can be hit and measured automatically. A new algorithm for this position determination is developed, based on a geometry model of the structure. After manually aiming the laser beam at 4 or more known points, the laser position and orientation relative to the structure is determined. Using this calculated position and orientation a list with the mirror angles for every measurement point is generated, which is used during the measurement. The algorithm is validated using 3 practical cases. In the first case a plate is used of which the points are measured very accurately, so the geometry model is assumed to be perfect. The second case is a brake disc. Here the geometry points are measured with a ruler, thus not so accurate. The final validation is done on a body in white of a car. A reduced finite element model is used as geometry model. This calibration shows that the new algorithm is very effective and practically usable.

Investigating and understanding the effects of multiple femtosecond laser scans on the surface topography of stainless steel 304 and titanium

Energy Technology Data Exchange (ETDEWEB)

Ling, Edwin Jee Yang, E-mail: edwin.ling@mail.mcgill.ca [Department of Chemical Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada); Saïd, Julien, E-mail: julien.said@ecl2015.ec-lyon.fr [Department of Chemical Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada); Brodusch, Nicolas, E-mail: nicolas.brodusch@mcgill.ca [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada); Gauvin, Raynald, E-mail: raynald.gauvin@mcgill.ca [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada); Servio, Phillip, E-mail: phillip.servio@mcgill.ca [Department of Chemical Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada); Kietzig, Anne-Marie, E-mail: anne.kietzig@mcgill.ca [Department of Chemical Engineering, McGill University, 3610 University Street, Montréal, Québec, H3A 0C5 (Canada)

2015-10-30

Highlights: • Effect of multiple femtosecond laser scans on stainless steel. • Ellipsoidal cones, columnar and chaotic structures observed on irradiated surface. • Chemical, crystallographic, and topographical analyses of ellipsoidal cones. • Developed mechanism for formation and growth of ellipsoidal cones. - Abstract: The majority of studies performed on the formation of surface features by femtosecond laser radiation focuses on single scan procedures, i.e. manipulating the laser beam once over the target area to fabricate different surface topographies. In this work, the effect of scanning stainless steel 304 multiple times with femtosecond laser pulses is thoroughly investigated over a wide range of fluences. The resultant laser-induced surface topographies can be categorized into two different regimes. In the low fluence regime (F{sub Σline,max} < 130 J/cm{sup 2}), ellipsoidal cones (randomly distributed surface protrusions covered by several layers of nanoparticles) are formed. Based on chemical, crystallographic, and topographical analyses, we conclude that these ellipsoidal cones are composed of unablated steel whose conical geometry offers a significant degree of fluence reduction (35–52%). Therefore, the rest of the irradiated area is preferentially ablated at a higher rate than the ellipsoidal cones. The second, or high fluence regime (F{sub Σline,max} > 130 J/cm{sup 2}) consists of laser-induced surface patterns such as columnar and chaotic structures. Here, the surface topography showed little to no change even when the target was scanned repeatedly. This is in contrast to the ellipsoidal cones, which evolve and grow continuously as more laser passes are applied.

Measurement of shape property distributions of quartzite aggregate from different crushers using 3D laser scanning system

CSIR Research Space (South Africa)

Mgangira, MB

2016-01-01

Full Text Available four crushers. In this paper, a description is provided on the quantification of particle shapes using data from a 3-D laser scanning device. The images from the laser were fully utilized in quantifying the shape descriptors in order to identify...

INCREASE OF READABILITY AND ACCURACY OF 3D MODELS USING FUSION OF CLOSE RANGE PHOTOGRAMMETRY AND LASER SCANNING

Directory of Open Access Journals (Sweden)

M. Gašparović

2012-07-01

Full Text Available The development of laser scanning technology has opened a new page in geodesy and enabled an entirely new way of presenting data. Products obtained by the method of laser scanning are used in many sciences, as well as in archaeology. It should be noted that 3D models of archaeological artefacts obtained by laser scanning are fully measurable, written in 1:1 scale and have high accuracy. On the other hand, texture and RGB values of the surface of the object obtained by a laser scanner have lower resolution and poorer radiometric characteristics in relation to the textures captured with a digital camera. Scientific research and the goal of this paper are to increase the accuracy and readability of the 3D model with textures obtained with a digital camera. Laser scanning was performed with triangulation scanner of high accuracy, Vivid 9i (Konica Minolta, while for photogrammetric recording digital camera Nikon D90 with a lens of fixed focal length 20 mm, was used. It is important to stress that a posteriori accuracy score of the global registration of point clouds in the form of the standard deviation was ± 0.136 mm while the average distance was only ± 0.080 mm. Also research has proven that the quality projection texture model increases readability. Recording of archaeological artefacts and making their photorealistic 3D model greatly contributes to archaeology as a science, accelerates processing and reconstruction of the findings. It also allows the presentation of findings to the general public, not just to the experts.

Accuracy in estimation of timber assortments and stem distribution - A comparison of airborne and terrestrial laser scanning techniques

Science.gov (United States)

Kankare, Ville; Vauhkonen, Jari; Tanhuanpää, Topi; Holopainen, Markus; Vastaranta, Mikko; Joensuu, Marianna; Krooks, Anssi; Hyyppä, Juha; Hyyppä, Hannu; Alho, Petteri; Viitala, Risto

2014-11-01

Detailed information about timber assortments and diameter distributions is required in forest management. Forest owners can make better decisions concerning the timing of timber sales and forest companies can utilize more detailed information to optimize their wood supply chain from forest to factory. The objective here was to compare the accuracies of high-density laser scanning techniques for the estimation of tree-level diameter distribution and timber assortments. We also introduce a method that utilizes a combination of airborne and terrestrial laser scanning in timber assortment estimation. The study was conducted in Evo, Finland. Harvester measurements were used as a reference for 144 trees within a single clear-cut stand. The results showed that accurate tree-level timber assortments and diameter distributions can be obtained, using terrestrial laser scanning (TLS) or a combination of TLS and airborne laser scanning (ALS). Saw log volumes were estimated with higher accuracy than pulpwood volumes. The saw log volumes were estimated with relative root-mean-squared errors of 17.5% and 16.8% with TLS and a combination of TLS and ALS, respectively. The respective accuracies for pulpwood were 60.1% and 59.3%. The differences in the bucking method used also caused some large errors. In addition, tree quality factors highly affected the bucking accuracy, especially with pulpwood volume.

Heat profiles of laser-irradiated nails.

Science.gov (United States)

Paasch, Uwe; Nenoff, Pietro; Seitz, Anna-Theresa; Wagner, Justinus A; Kendler, Michael; Simon, Jan C; Grunewald, Sonja

2014-01-01

Onychomycosis is a worldwide problem with no tendency for self-healing, and existing systemic treatments achieve disease-free nails in only 35 to 76% of cases. Recently, treatment of nail fungus with a near-infrared laser has been introduced. It is assumed that fungal eradication is mediated by local heat. To investigate if laser treatment has the potential to eradicate fungal hyphae and arthrospores, laser heat application and propagation needs to be studied in detail. This study aimed to measure nail temperatures using real-time videothermography during laser irradiation. Treatment was performed using 808- and 980-nm linear scanning diode lasers developed for hair removal, enabling contact-free homogeneous irradiation of a human nail plate in one pass. Average and peak temperatures increased pass by pass, while the laser beam moved along the nail plates. The achieved mean peak temperatures (808 nm: 74.1 to 112.4°C, 980 nm: 45.8 to 53.5°C), as well as the elevation of average temperatures (808 nm: 29.5 to 38.2°C, 980 nm: 27.1 to 32.6°C) were associated with pain that was equivalent to that of hair removal procedures and was not significantly different for various wavelengths. The linear scanning laser devices provide the benefits of contact-free homogeneous heating of the human nail while ensuring adequate temperature rises.

A Visualization Method for Corrosion Damage on Aluminum Plates Using an Nd:YAG Pulsed Laser Scanning System.

Science.gov (United States)

Lee, Inbok; Zhang, Aoqi; Lee, Changgil; Park, Seunghee

2016-12-16

This paper proposes a non-contact nondestructive evaluation (NDE) technique that uses laser-induced ultrasonic waves to visualize corrosion damage in aluminum alloy plate structures. The non-contact, pulsed-laser ultrasonic measurement system generates ultrasonic waves using a galvanometer-based Q-switched Nd:YAG laser and measures the ultrasonic waves using a piezoelectric (PZT) sensor. During scanning, a wavefield can be acquired by changing the excitation location of the laser point and measuring waves using the PZT sensor. The corrosion damage can be detected in the wavefield snapshots using the scattering characteristics of the waves that encounter corrosion. The structural damage is visualized by calculating the logarithmic values of the root mean square (RMS), with a weighting parameter to compensate for the attenuation caused by geometrical spreading and dispersion of the waves. An intact specimen is used to conduct a comparison with corrosion at different depths and sizes in other specimens. Both sides of the plate are scanned with the same scanning area to observe the effect of the location where corrosion has formed. The results show that the damage can be successfully visualized for almost all cases using the RMS-based functions, whether it formed on the front or back side. Also, the system is confirmed to have distinguished corroded areas at different depths.

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

Science.gov (United States)

Zou, Ying; Celli, Anna; Zhu, Hanjiang; Elmahdy, Akram; Cao, Yachao; Hui, Xiaoying; Maibach, Howard

2017-01-01

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. 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. 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. 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.

SENSOR-TOPOLOGY BASED SIMPLICIAL COMPLEX RECONSTRUCTION FROM MOBILE LASER SCANNING

Directory of Open Access Journals (Sweden)

S. Guinard

2018-05-01

Full Text Available We propose a new method for the reconstruction of simplicial complexes (combining points, edges and triangles from 3D point clouds from Mobile Laser Scanning (MLS. Our main goal is to produce a reconstruction of a scene that is adapted to the local geometry of objects. Our method uses the inherent topology of the MLS sensor to define a spatial adjacency relationship between points. We then investigate each possible connexion between adjacent points and filter them by searching collinear structures in the scene, or structures perpendicular to the laser beams. Next, we create triangles for each triplet of self-connected edges. Last, we improve this method with a regularization based on the co-planarity of triangles and collinearity of remaining edges. We compare our results to a naive simplicial complexes reconstruction based on edge length.

Analysis of calibration-free wavelength-scanned wavelength modulation spectroscopy for practical gas sensing using tunable diode lasers

Science.gov (United States)

Sun, K.; Chao, X.; Sur, R.; Goldenstein, C. S.; Jeffries, J. B.; Hanson, R. K.

2013-12-01

A novel strategy has been developed for analysis of wavelength-scanned, wavelength modulation spectroscopy (WMS) with tunable diode lasers (TDLs). The method simulates WMS signals to compare with measurements to determine gas properties (e.g., temperature, pressure and concentration of the absorbing species). Injection-current-tuned TDLs have simultaneous wavelength and intensity variation, which severely complicates the Fourier expansion of the simulated WMS signal into harmonics of the modulation frequency (fm). The new method differs from previous WMS analysis strategies in two significant ways: (1) the measured laser intensity is used to simulate the transmitted laser intensity and (2) digital lock-in and low-pass filter software is used to expand both simulated and measured transmitted laser intensities into harmonics of the modulation frequency, WMS-nfm (n = 1, 2, 3,…), avoiding the need for an analytic model of intensity modulation or Fourier expansion of the simulated WMS harmonics. This analysis scheme is valid at any optical depth, modulation index, and at all values of scanned-laser wavelength. The method is demonstrated and validated with WMS of H2O dilute in air (1 atm, 296 K, near 1392 nm). WMS-nfm harmonics for n = 1 to 6 are extracted and the simulation and measurements are found in good agreement for the entire WMS lineshape. The use of 1f-normalization strategies to realize calibration-free wavelength-scanned WMS is also discussed.

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

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 mic...

Cryogen spray cooling during laser tissue welding.

Science.gov (United States)

Fried, N M; Walsh, J T

2000-03-01

Cryogen cooling during laser tissue welding was explored as a means of reducing lateral thermal damage near the tissue surface and shortening operative time. Two centimetre long full-thickness incisions were made on the epilated backs of guinea pigs, in vivo. India ink was applied to the incision edges then clamps were used to appose the edges. A 4 mm diameter beam of 16 W, continuous-wave, 1.06 microm, Nd:YAG laser radiation was scanned over the incisions, producing approximately 100 ms pulses. There was a delay of 2 s between scans. The total irradiation time was varied from 1-2 min. Cryogen was delivered to the weld site through a solenoid valve in spurt durations of 20, 60 and 100 ms. The time between spurts was either 2 or 4 s, corresponding to one spurt every one or two laser scans. Histology and tensile strength measurements were used to evaluate laser welds. Total irradiation times were reduced from 10 min without surface cooling to under 1 min with surface cooling. The thermal denaturation profile showed less denaturation in the papillary dermis than in the mid-dermis. Welds created using optimized irradiation and cooling parameters had significantly higher tensile strengths (1.7 +/- 0.4 kg cm(-2)) than measured in the control studies without cryogen cooling (1.0 +/- 0.2 kg cm(-2)) (p laser welding results in increased weld strengths while reducing thermal damage and operative times. Long-term studies will be necessary to determine weld strengths and the amount of scarring during wound healing.

Comparison of Pain Response of Patients Undergoing Panretinal Photocoagulation for Proliferative Diabetic Retinopathy: 532 nm Standard Laser vs. Multispot Pattern Scan Laser

Directory of Open Access Journals (Sweden)

Göktuğ Seymenoğlu

2013-08-01

Full Text Available Purpose: To compare pain response of patients undergoing panretinal photocoagulation (PRP for proliferative diabetic retinopathy (PDR using 532 nm standard laser versus multispot pattern scan laser and to evaluate the relationship between pain response and patient characteristics. Material and Method: Thirty-five patients had PRP with the Pascal system in a single session, while other 35 patients had PRP with conventional laser in 2 sessions. Parameters used in conventional laser were as follows: spot size 200 µm, exposure time 0.2 s, and power sufficient to produce visible grey-white burns. We used same spot size, 20-30 ms exposure time, and higher levels of laser power in order to get a similar endpoint in the Pascal system. The patients were required to evaluate the severity of pain on a visual analog scale (VAS and verbally 5 minutes after PRP with Pascal and 5 minutes after the first session of PRP with conventional laser. The relationship between pain experienced and patient characteristics was evaluated. Results: At baseline, both groups did not differ significantly (p >0.05, for all with respect to sex, age, duration of diabetes, most recent HbA1c, treatment regimen, or patient experience. The patients in the Pascal group had a mean pain score of 0.55±0.70 on verbal scale and 1.54±1.22 on VAS compared to 2.17±1.18 and 5.54±3.28, respectively in the conventional laser group which was, statistically, significantly different in both scales (p<0.05. Discussion: Our study confirms that new generation pattern scanning photocoagulators satisfactorily decrease the pain by shortening the exposure time while increasing the laser power. (Turk J Ophthalmol 2013; 43: 221-4

3D laser scanning techniques applying to tunnel documentation and geological mapping at Aespoe hard rock laboratory, Sweden

International Nuclear Information System (INIS)

Feng, Q.; Wang, G.; Roeshoff, K.

2008-01-01

3D terrestrial laser scanning is nowadays one of the most attractive methods to applying for 3D mapping and documentation of rock faces and tunnels, and shows the most potential to improve the data quality and provide some good solutions in rock engineering projects. In this paper, the state-of-the-art methods are described for different possibility to tunnel documentation and geological mapping based on 3D laser scanning data. Some results are presented from the case study performed at the Hard Rock Laboratory, Aespoe run by SKB, Swedish Nuclear Fuel and Waste Management Co. Comparing to traditional methods, 3D laser scanning techniques can not only provide us with a rapid and 3D digital way for tunnel documentation, but also create a potential chance to achieve high quality data, which might be beneficial to different rock engineering project procedures, including field data acquisition, data processing, data retrieving and management, and also modeling and design. (authors)

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.

Characterizing the geomorphic setting of precariously balanced rocks using terrestrial laser scanning technology

Science.gov (United States)

Haddad, D. E.; Arrowsmith, R.

2009-12-01

Terrestrial laser scanning (TLS) technology is rapidly becoming an effective three-dimensional imaging tool. Precariously balanced rocks are a subset of spheroidally weathered boulders. They are balanced on bedrock pedestals and are formed in upland drainage basins and pediments of exhumed plutons. Precarious rocks are used as negative evidence of earthquake-driven extreme ground motions. Field surveys of PBRs are coupled with cosmogenic radionuclide (CRN) surface exposure dating techniques to determine their exhumation rates. These rates are used in statistical simulations to estimate the magnitudes and recurrences of earthquake-generated extreme ground shaking as a means to physically validate seismic hazard analyses. However, the geomorphic setting of PBRs in the landscape is poorly constrained when interpreting their exhumation rates from CRN surface exposure dates. Are PBRs located on steep or gentle hillslopes? Are they located near drainages or hillslope crests? What geomorphic processes control the spatial distribution of PBRs in a landscape, and where do these processes dominate? Because the fundamental hillslope transport laws are largely controlled by local hillslope gradient and contributing area, the location of a PBR is controlled by the geomorphic agents and their rates acting on it. Our latest efforts involve using a combination of TLS and airborne laser swath mapping (ALSM) to characterize the geomorphic situation of PBRs. We used a Riegl LPM 800i (LPM 321) terrestrial laser scanner to scan a ~1.5 m tall by ~1 m wide precariously balanced rock in the Granite Dells, central Arizona. The PBR was scanned from six positions, and the scans were aligned to a point cloud totaling 3.4M points. We also scanned a ~50 m by ~150 m area covering PBR hillslopes from five scan positions. The resulting 5.5M points were used to create a digital terrain model of precarious rocks and their hillslopes. Our TLS- and ALSM-generated surface models and DEMs provide a

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.

A Classification-oriented Method of Feature Image Generation for Vehicle-borne Laser Scanning Point Clouds

Directory of Open Access Journals (Sweden)

YANG Bisheng

2016-02-01

Full Text Available An efficient method of feature image generation of point clouds to automatically classify dense point clouds into different categories is proposed, such as terrain points, building points. The method first uses planar projection to sort points into different grids, then calculates the weights and feature values of grids according to the distribution of laser scanning points, and finally generates the feature image of point clouds. Thus, the proposed method adopts contour extraction and tracing means to extract the boundaries and point clouds of man-made objects (e.g. buildings and trees in 3D based on the image generated. Experiments show that the proposed method provides a promising solution for classifying and extracting man-made objects from vehicle-borne laser scanning point clouds.

Generation of 3D Virtual Geographic Environment Based on Laser Scanning Technique

Institute of Scientific and Technical Information of China (English)

DU Jie; CHEN Xiaoyong; FumioYamazaki

2003-01-01

This paper demonstrates an experiment on the generation of 3D virtual geographic environment on the basis of experimental flight laser scanning data by a set of algorithms and methods that were developed to automatically interpret range images for extracting geo-spatial features and then to reconstruct geo-objects. The algorithms and methods for the interpretation and modeling of laser scanner data include triangulated-irregular-network (TIN)-based range image interpolation ; mathematical-morphology(MM)-based range image filtering,feature extraction and range image segmentation, feature generalization and optimization, 3D objects reconstruction and modeling; computergraphics (CG)-based visualization and animation of geographic virtual reality environment.

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.

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.

Comparison of 2 root surface area measurement methods: 3-dimensional laser scanning and cone-beam computed tomography

International Nuclear Information System (INIS)

Tasanapanont, Jintana; Apisariyakul, Janya; Wattanachai, Tanapan; Jotikasthira, Dhirawat; Sriwilas, Patiyut; Midtboe, Marit

2017-01-01

The aim of this study was to compare the use of 3-dimensional (3D) laser scanning and cone-beam computed tomography (CBCT) as methods of root surface measurement. Thirty teeth (15 maxillary first premolars and 15 mandibular first premolars) from 8 patients who required extractions for orthodontic treatment were selected. Before extraction, pre-treatment CBCT images of all the patients were recorded. First, a CBCT image was imported into simulation software (Mimics version 15.01; Materialise, Leuven, Belgium) and the root surface area of each tooth was calculated using 3-Matic (version 7.01, Materialise, Leuven, Belgium). After extraction, all the teeth were scanned and the root surface area of each extracted tooth was calculated. The root surface areas calculated using these 2 measurement methods were analyzed using the paired t-test (P<.05). Correlations between the 2 methods were determined by calculating the Pearson correlation coefficient. The intraclass correlation coefficient (ICC) was used to assess intraobserver reliability. The root surface area measurements (230.11±41.97 mm"2) obtained using CBCT were slightly greater than those (229.31±42.46 mm2) obtained using 3D laser scanning, but not significantly (P=.425). A high Pearson correlation coefficient was found between the CBCT and the 3D laser scanner measurements. The intraobserver ICC was 1.000 for 3D laser scanning and 0.990 for CBCT. This study presents a novel CBCT approach for measuring the root surface area; this technique can be used for estimating the root surface area of non-extracted teeth

Comparison of 2 root surface area measurement methods: 3-dimensional laser scanning and cone-beam computed tomography

Energy Technology Data Exchange (ETDEWEB)

Tasanapanont, Jintana; Apisariyakul, Janya; Wattanachai, Tanapan; Jotikasthira, Dhirawat [Dept. of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai (Thailand); Sriwilas, Patiyut [Dept. of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok (Thailand); Midtboe, Marit [Dept. of Clinical Dentistry - Orthodontics, Faculty of Medicine and Dentistry, University of Bergen, Bergen (Norway)

2017-06-15

The aim of this study was to compare the use of 3-dimensional (3D) laser scanning and cone-beam computed tomography (CBCT) as methods of root surface measurement. Thirty teeth (15 maxillary first premolars and 15 mandibular first premolars) from 8 patients who required extractions for orthodontic treatment were selected. Before extraction, pre-treatment CBCT images of all the patients were recorded. First, a CBCT image was imported into simulation software (Mimics version 15.01; Materialise, Leuven, Belgium) and the root surface area of each tooth was calculated using 3-Matic (version 7.01, Materialise, Leuven, Belgium). After extraction, all the teeth were scanned and the root surface area of each extracted tooth was calculated. The root surface areas calculated using these 2 measurement methods were analyzed using the paired t-test (P<.05). Correlations between the 2 methods were determined by calculating the Pearson correlation coefficient. The intraclass correlation coefficient (ICC) was used to assess intraobserver reliability. The root surface area measurements (230.11±41.97 mm{sup 2}) obtained using CBCT were slightly greater than those (229.31±42.46 mm2) obtained using 3D laser scanning, but not significantly (P=.425). A high Pearson correlation coefficient was found between the CBCT and the 3D laser scanner measurements. The intraobserver ICC was 1.000 for 3D laser scanning and 0.990 for CBCT. This study presents a novel CBCT approach for measuring the root surface area; this technique can be used for estimating the root surface area of non-extracted teeth.

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)

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

Determination of equivalent cross sections for representation of control rod regions in diffusion calculations

International Nuclear Information System (INIS)

Scherer, W.; Neef, H.J.

1976-07-01

The representation of control rod regions in reactor calculations requires a combination of transport and diffusion theory calculations. A method is described which produces equivalent cross sections for a rodded region. These cross sections used in a diffusion theory calcualtion yield the same rod efficiency and reaction rate distribution as the transport theory calculation for the explicit heterogeneous control rod. The description of the method is complemented by sample problems. (orig.) [de

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.

Photonic crystal fibre enables short-wavelength two-photon laser scanning fluorescence microscopy with fura-2

International Nuclear Information System (INIS)

McConnell, Gail; Riis, Erling

2004-01-01

We report on a novel and compact reliable laser source capable of short-wavelength two-photon laser scanning fluorescence microscopy based on soliton self-frequency shift effects in photonic crystal fibre. We demonstrate the function of the system by performing two-photon microscopy of smooth muscle cells and cardiac myocytes from the rat pulmonary vein and Chinese hamster ovary cells loaded with the fluorescent calcium indicator fura-2/AM

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.

Volumetric evolution of Surtsey, Iceland, from topographic maps and scanning airborne laser altimetry

Science.gov (United States)

Garvin, J.B.; Williams, R.S.; Frawley, J.J.; Krabill, W.B.

2000-01-01

The volumetric evolution of Surtsey has been estimated on the basis of digital elevation models derived from NASA scanning airborne laser altimeter surveys (20 July 1998), as well as digitized 1:5,000-scale topographic maps produced by the National Land Survey of Iceland and by Norrman. Subaerial volumes have been computed from co-registered digital elevation models (DEM's) from 6 July 1968, 11 July 1975, 16 July 1993, and 20 July 1998 (scanning airborne laser altimetry), as well as true surface area (above mean sea level). Our analysis suggests that the subaerial volume of Surtsey has been reduced from nearly 0.100 km3 on 6 July 1968 to 0.075 km3 on 20 July 1998. Linear regression analysis of the temporal evolution of Surtsey's subaerial volume indicates that most of its subaerial surface will be at or below mean sea-level by approximately 2100. This assumes a conservative estimate of continuation of the current pace of marine erosion and mass-wasting on the island, including the indurated core of the conduits of the Surtur I and Surtur II eruptive vents. If the conduits are relatively resistant to marine erosion they will become sea stacks after the rest of the island has become a submarine shoal, and some portions of the island could survive for centuries. The 20 July 1998 scanning laser altimeter surveys further indicate rapid enlargement of erosional canyons in the northeastern portion of the partial tephra ring associated with Surtur I. Continued airborne and eventually spaceborne topographic surveys of Surtsey are planned to refine the inter-annual change of its subaerial volume.

Mapping Vineyard Leaf Area Using Mobile Terrestrial Laser Scanners: Should Rows be Scanned On-the-Go or Discontinuously Sampled?

Directory of Open Access Journals (Sweden)

Ignacio del-Moral-Martínez

2016-01-01

Full Text Available The leaf area index (LAI is defined as the one-side leaf area per unit ground area, and is probably the most widely used index to characterize grapevine vigor. However, LAI varies spatially within vineyard plots. Mapping and quantifying this variability is very important for improving management decisions and agricultural practices. In this study, a mobile terrestrial laser scanner (MTLS was used to map the LAI of a vineyard, and then to examine how different scanning methods (on-the-go or discontinuous systematic sampling may affect the reliability of the resulting raster maps. The use of the MTLS allows calculating the enveloping vegetative area of the canopy, which is the sum of the leaf wall areas for both sides of the row (excluding gaps and the projected upper area. Obtaining the enveloping areas requires scanning from both sides one meter length section along the row at each systematic sampling point. By converting the enveloping areas into LAI values, a raster map of the latter can be obtained by spatial interpolation (kriging. However, the user can opt for scanning on-the-go in a continuous way and compute 1-m LAI values along the rows, or instead, perform the scanning at discontinuous systematic sampling within the plot. An analysis of correlation between maps indicated that MTLS can be used discontinuously in specific sampling sections separated by up to 15 m along the rows. This capability significantly reduces the amount of data to be acquired at field level, the data storage capacity and the processing power of computers.

Automatic segmentation of cell nuclei from confocal laser scanning microscopy images

International Nuclear Information System (INIS)

Kelemen, A.; Reist, H.W.

1997-01-01

A newly developed experimental method combines the possibility of irradiating more than a thousand cells simultaneous with an efficient colony-forming ability and with the capability of localizing a particle track through a cell nucleus together with the assessment of the energy transfer by digital superposition of the image containing the track with that of the cells. To assess the amount of energy deposition by particles traversing the cell nucleus the intersection lengths of the particle tracks have to be known. Intersection lengths can be obtained by determining the 3D surface contours of the irradiated cell nuclei. Confocal laser scanning microscopy using specific DNA fluorescent dye offers a possible way for the determination of the 3D shape of individual nuclei. Unfortunately, such experiments cannot be performed on living cells. One solution to this problem can be provided by building a statistical model of the shape of the nuclei of the exposed cells. In order to build such a statistical model, a large number of cell nuclei have to be identified and segmented from confocal laser scanning microscopy images. The present paper describes a method to perform this 3D segmentation in an automatic manner in order to create a solid basis for the statistical model. (author) 2 figs., 4 refs

Compact Multipurpose Mobile Laser Scanning System — Initial Tests and Results

Directory of Open Access Journals (Sweden)

Craig Glennie

2013-01-01

Full Text Available We describe a prototype compact mobile laser scanning system that may be operated from a backpack or unmanned aerial vehicle. The system is small, self-contained, relatively inexpensive, and easy to deploy. A description of system components is presented, along with the initial calibration of the multi-sensor platform. The first field tests of the system, both in backpack mode and mounted on a helium balloon for real-world applications are presented. For both field tests, the acquired kinematic LiDAR data are compared with highly accurate static terrestrial laser scanning point clouds. These initial results show that the vertical accuracy of the point cloud for the prototype system is approximately 4 cm (1σ in balloon mode, and 3 cm (1σ in backpack mode while horizontal accuracy was approximately 17 cm (1σ for the balloon tests. Results from selected study areas on the Sacramento River Delta and San Andreas Fault in California demonstrate system performance, deployment agility and flexibility, and potential for operational production of high density and highly accurate point cloud data. Cost and production rate trade-offs place this system in the niche between existing airborne and tripod mounted LiDAR systems.

Local annealing of shape memory alloys using laser scanning and computer vision

Science.gov (United States)

Hafez, Moustapha; Bellouard, Yves; Sidler, Thomas C.; Clavel, Reymond; Salathe, Rene-Paul

2000-11-01

A complete set-up for local annealing of Shape Memory Alloys (SMA) is proposed. Such alloys, when plastically deformed at a given low temperature, have the ability to recover a previously memorized shape simply by heating up to a higher temperature. They find more and more applications in the fields of robotics and micro engineering. There is a tremendous advantage in using local annealing because this process can produce monolithic parts, which have different mechanical behavior at different location of the same body. Using this approach, it is possible to integrate all the functionality of a device within one piece of material. The set-up is based on a 2W-laser diode emitting at 805nm and a scanner head. The laser beam is coupled into an optical fiber of 60(mu) in diameter. The fiber output is focused on the SMA work-piece using a relay lens system with a 1:1 magnification, resulting in a spot diameter of 60(mu) . An imaging system is used to control the position of the laser spot on the sample. In order to displace the spot on the surface a tip/tilt laser scanner is used. The scanner is positioned in a pre-objective configuration and allows a scan field size of more than 10 x 10 mm2. A graphical user interface of the scan field allows the user to quickly set up marks and alter their placement and power density. This is achieved by computer controlling X and Y positions of the scanner as well as the laser diode power. A SMA micro-gripper with a surface area less than 1 mm2 and an opening of the jaws of 200(mu) has been realized using this set-up. It is electrically actuated and a controlled force of 16mN can be applied to hold and release small objects such as graded index micro-lenses at a cycle time of typically 1s.