Multichannel High Resolution Wide Swath SAR Imaging for Hypersonic Air Vehicle with Curved Trajectory

Directory of Open Access Journals (Sweden)

Rui Zhou

2018-01-01

Full Text Available Synthetic aperture radar (SAR equipped on the hypersonic air vehicle in near space has many advantages over the conventional airborne SAR. However, its high-speed maneuvering characteristics with curved trajectory result in serious range migration, and exacerbate the contradiction between the high resolution and wide swath. To solve this problem, this paper establishes the imaging geometrical model matched with the flight trajectory of the hypersonic platform and the multichannel azimuth sampling model based on the displaced phase center antenna (DPCA technology. Furthermore, based on the multichannel signal reconstruction theory, a more efficient spectrum reconstruction model using discrete Fourier transform is proposed to obtain the azimuth uniform sampling data. Due to the high complexity of the slant range model, it is difficult to deduce the processing algorithm for SAR imaging. Thus, an approximate range model is derived based on the minimax criterion, and the optimal second-order approximate coefficients of cosine function are obtained using the two-population coevolutionary algorithm. On this basis, aiming at the problem that the traditional Omega-K algorithm cannot compensate the residual phase with the difficulty of Stolt mapping along the range frequency axis, this paper proposes an Exact Transfer Function (ETF algorithm for SAR imaging, and presents a method of range division to achieve wide swath imaging. Simulation results verify the effectiveness of the ETF imaging algorithm.

Multichannel High Resolution Wide Swath SAR Imaging for Hypersonic Air Vehicle with Curved Trajectory.

Science.gov (United States)

Zhou, Rui; Sun, Jinping; Hu, Yuxin; Qi, Yaolong

2018-01-31

Synthetic aperture radar (SAR) equipped on the hypersonic air vehicle in near space has many advantages over the conventional airborne SAR. However, its high-speed maneuvering characteristics with curved trajectory result in serious range migration, and exacerbate the contradiction between the high resolution and wide swath. To solve this problem, this paper establishes the imaging geometrical model matched with the flight trajectory of the hypersonic platform and the multichannel azimuth sampling model based on the displaced phase center antenna (DPCA) technology. Furthermore, based on the multichannel signal reconstruction theory, a more efficient spectrum reconstruction model using discrete Fourier transform is proposed to obtain the azimuth uniform sampling data. Due to the high complexity of the slant range model, it is difficult to deduce the processing algorithm for SAR imaging. Thus, an approximate range model is derived based on the minimax criterion, and the optimal second-order approximate coefficients of cosine function are obtained using the two-population coevolutionary algorithm. On this basis, aiming at the problem that the traditional Omega-K algorithm cannot compensate the residual phase with the difficulty of Stolt mapping along the range frequency axis, this paper proposes an Exact Transfer Function (ETF) algorithm for SAR imaging, and presents a method of range division to achieve wide swath imaging. Simulation results verify the effectiveness of the ETF imaging algorithm.

Swath width study. A simulation assessment of costs and benefits of a sensor system for agricultural application

Science.gov (United States)

1979-01-01

Satellites provide an excellent platform from which to observe crops on the scale and frequency required to provide accurate crop production estimates on a worldwide basis. Multispectral imaging sensors aboard these platforms are capable of providing data from which to derive acreage and production estimates. The issue of sensor swath width was examined. The quantitative trade trade necessary to resolve the combined issue of sensor swath width, number of platforms, and their orbits was generated and are included. Problems with different swath width sensors were analyzed and an assessment of system trade-offs of swath width versus number of satellites was made for achieving Global Crop Production Forecasting.

Using High-Resolution Swath Mapping Data and Other Underway Geophysical Measurements Collected during Transit Cruises of RV Isabu to Map Deep Sea Floor of the Pacific and Indian Oceans

Science.gov (United States)

Hong, G. H.; Lee, S. M.; Kim, D. J.; Lee, Y. H.; Kim, S. S.

2017-12-01

Detail images of the seafloor are often the first collection of clues that set one towards a path that leads to a new discovery. The mapping of unchartered seafloor is like exploring the surface of an unknown planet for the first time. The launch of new global-ocean-class RV Isabu operated by Korea Institute of Ocean Science and Technology (KIOST) in November 2016 has reinvigorated the ongoing open ocean research in Korea. The location of the KIOST research vessels can be found at http://www.kiost.net/. Here we present a new collaborative research and education program which utilizes onboard measurements taken during the transit cruises. The measurements include high-resolution swath mapping bathymetric data, underway geophysical measurements (3.5 kHz subbottom profile, sea surface gravity and magnetic field) which are gathered semi-automatically during a scientific operation. The acquisition of data alone is not sufficient for meaningful scientific knowledge as the initial measurements must be cleaned and processed during or after the cruise. As in any scientific endeavor, planning is important. Prior to the cruise, preliminary study will be carried out by carefully examining the previously collected data from various global databases. Whenever possible, a small offset will be made of the ship track lines crossing the region so that important new measurements can be obtained systematically over the years. We anticipate that the program will not only contribute to fill the gap in the high-resolution bathymetry in some part of the Indian Ocean and Pacific. The processed and analyzed data will be available to other scientific communities for further understanding via download from KIOST website.

Bathymetry from fusion of airborne hyperspectral and laser data

Science.gov (United States)

Kappus, Mary E.; Davis, Curtiss O.; Rhea, W. Joseph

1998-10-01

Airborne hyperspectral and nadir-viewing laser data can be combined to ascertain shallow water bathymetry. The combination emphasizes the advances and overcomes the disadvantages of each method used alone. For laser systems, both the hardware and software for obtaining off-nadir measurement are complicated and expensive, while for the nadir view the conversion of laser pulse travel time to depth is straightforward. The hyperspectral systems can easily collect data in a full swath, but interpretation for water depth requires careful calibration and correction for transmittance through the atmosphere and water. Relative depths are apparent in displays of several subsets of hyperspectral data, for example, single blue-green wavelengths, endmembers that represent the pure water component of the data, or ratios of deep to shallow water endmembers. A relationship between one of these values and the depth measured by the aligned nadir laser can be determined, and then applied to the rest of the swath to obtain depth in physical units for the entire area covered. We demonstrate this technique using bathymetric charts as a proxy for laser data, and hyperspectral data taken by AVIRIS over Lake Tahoe and Key West.

The effect of wide swathing on wilting times and nutritive value of alfalfa haylage.

Science.gov (United States)

Kung, L; Stough, E C; McDonell, E E; Schmidt, R J; Hofherr, M W; Reich, L J; Klingerman, C M

2010-04-01

On 3 consecutive cuttings, alfalfa from a single field was mowed with a John Deere 946 mower-conditioner (4-m cut width; Moline, IL) to leave narrow swaths (NS) ranging from 1.2 to 1.52 m wide (30-37% of cutter bar width) and wide swaths (WS) ranging from 2.44 to 2.74 m wide (62-67% of cutter bar width). Samples were collected from windrows and dry matter (DM) was monitored during wilting until a target of 43 to 45% DM was obtained. Forage from random windrows (n=4-6) was harvested by hand, chopped through a forage harvester before being packed in replicated vacuum-sealed bags, and allowed to ensile for 65 d. There was no swath width x cutting interaction for any parameter tested. Over all cuttings, the resulting silage DM was not different between the NS silage (43.8%) and the WS silage (44.9%). However, wide swathing greatly reduced the time of wilting before making silage. The hours of wilting time needed to reach the targeted DM for the NS silage compared with the WS silage at cuttings 1, 2, and 3 were 50 versus 29, 54 versus 28, and 25 versus 6, respectively. At the time of ensiling, the WS silage had more water-soluble carbohydrates (5.1%) than did the NS silage (3.7%). The WS silage had a lower pH (4.58) than did the NS silage (4.66), but swath width did not affect fermentation end products (lactic acid, acetic acid, and ethanol). The NS silage had more NH(3)-N (0.26%) than did the WS silage (0.21%). Wide swathing did not affect the concentration of ash or the digestibility of NDF, but it lowered the N content (NS=3.45%; WS=3.23%) and increased the ADF content (NS=39.7%; WS=40.9%) of the resulting silage. Wide swathing can markedly reduce the time that alfalfa must wilt before it can be chopped for silage, but under good conditions, as in this study, the resulting silage quality was generally not improved. Copyright (c) 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Four-dimensional optoacoustic temperature mapping in laser-induced thermotherapy

Science.gov (United States)

Oyaga Landa, Francisco Javier; Deán-Ben, Xosé Luís.; Sroka, Ronald; Razansky, Daniel

2018-02-01

Photoablative laser therapy is in common use for selective destruction of malignant masses, vascular and brain abnormalities. Tissue ablation and coagulation are irreversible processes occurring shortly after crossing a certain thermal exposure threshold. As a result, accurate mapping of the temperature field is essential for optimizing the outcome of these clinical interventions. Here we demonstrate four-dimensional optoacoustic temperature mapping of the entire photoablated region. Accuracy of the method is investigated in tissue-mimicking phantom experiments. Deviations of the volumetric optoacoustic temperature readings provided at 40ms intervals remained below 10% for temperature elevations above 3°C, as validated by simultaneous thermocouple measurements. The excellent spatio-temporal resolution of the new temperature monitoring approach aims at improving safety and efficacy of laser-based photothermal procedures.

Retrieval Algorithms for Road Surface Modelling Using Laser-Based Mobile Mapping

Directory of Open Access Journals (Sweden)

Antero Kukko

2008-09-01

Full Text Available Automated processing of the data provided by a laser-based mobile mapping system will be a necessity due to the huge amount of data produced. In the future, vehiclebased laser scanning, here called mobile mapping, should see considerable use for road environment modelling. Since the geometry of the scanning and point density is different from airborne laser scanning, new algorithms are needed for information extraction. In this paper, we propose automatic methods for classifying the road marking and kerbstone points and modelling the road surface as a triangulated irregular network. On the basis of experimental tests, the mean classification accuracies obtained using automatic method for lines, zebra crossings and kerbstones were 80.6%, 92.3% and 79.7%, respectively.

Sub-nanometrically resolved chemical mappings of quantum-cascade laser active regions

International Nuclear Information System (INIS)

Pantzas, Konstantinos; Beaudoin, Grégoire; Patriarche, Gilles; Largeau, Ludovic; Mauguin, Olivia; Sagnes, Isabelle; Pegolotti, Giulia; Vasanelli, Angela; Calvar, Ariane; Amanti, Maria; Sirtori, Carlo

2016-01-01

A procedure that produces sub-nanometrically resolved chemical mappings of MOCVD-grown InGaAs/InAlAs/InP quantum cascade lasers is presented. The chemical mappings reveal that, although the structure is lattice-matched to InP, the InAlAs barriers do not attain the nominal aluminum content—48%—and are, in fact, InGaAlAs quaternaries. This information is used to adjust the aluminum precursor flow and fine-tune the composition of the barriers, resulting in a significant improvement of the fabricated lasers. (paper)

Forage intake and wastage by ewes in pea/hay barley swath grazing and bale feeding systems

Science.gov (United States)

Harvested feed costs, particularly during the winter, are traditionally the highest input associated with a ruminant livestock operation. Although swath grazing has been practiced for over 100 years and literature exists for cattle use of swath grazing, no published results are available on use of s...

Mapping GPS multipath: a case study for the lunar laser ranger ...

African Journals Online (AJOL)

We investigate and attempt to map multipath as part of the site investigation for the installation of the timing antenna for lunar laser ranging applications at the Hartebeesthoek Radio Astronomy Observatory (HartRAO). A high-resolution wavelet power spectrum and a standard deviation parameter are used to map multipath ...

ANTIMICROBIAL BIO-NONWOVEN FABRICS FOR EYES'S SWATH AND DIAPERS FOR INFANT'S INCUBATORS

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ElSayed A. ElNashar

2016-12-01

Full Text Available An infant incubator is a piece of equipment common to pediatric hospitals, birthing centers and neonatal intensive care units. While the unit may serve several specific functions, it is generally used to provide a safe and stable environment for newborn infants, often those who were born prematurely or with an illness or disability that makes them especially vulnerable for the first several months of life. The objective of this research was to gain a better understanding of New Approach for a Bio-Nonwoven fabrics and infant's incubator in terms of the specific materials as MaterBi/PCL® as Bioplastic and the elements of comfort, drivers associated with it and its waste biodegradation by different methods. Shortly after birth, the beginning in first hours of life babies with neonatal, a byproduct of the red blood cells decomposition. Many convenient features to consider with tow basic disposable eyes` swathe and diapers on infant’s incubator options: cloth of basic disposable eyes` swathe and diapers, with their end use properties. The form design of eyes` swathe® and diapers® shapes, for infant’s incubator stage then consider convenience, cost, and environmental waste.

ASTC-MIMO-TOPS Mode with Digital Beam-Forming in Elevation for High-Resolution Wide-Swath Imaging

Directory of Open Access Journals (Sweden)

Pingping Huang

2015-03-01

Full Text Available Future spaceborne synthetic aperture radar (SAR missions require complete and frequent coverage of the earth with a high resolution. Terrain Observation by Progressive Scans (TOPS is a novel wide swath mode but has impaired azimuth resolution. In this paper, an innovative extended TOPS mode named Alamouti Space-time Coding multiple-input multiple-output TOPS (ASTC-MIMO-TOPS mode combined with digital beam-forming (DBF in elevation and multi-aperture SAR signal reconstruction in azimuth is proposed. This innovative mode achieves wide-swath coverage with a high geometric resolution and also overcomes major drawbacks in conventional MIMO SAR systems. The data processing scheme of this imaging scheme is presented in detail. The designed system example of the proposed ASTC-MIMO-TOPS mode, which has the imaging capacity of a 400 km wide swath with an azimuth resolution of 3 m, is given. Its system performance analysis results and simulated imaging results on point targets demonstrate the potential of the proposed novel spaceborne SAR mode for high-resolution wide-swath (HRWS imaging.

Examination of Laser Microprobe Vacuum Ultraviolet Ionization Mass Spectrometry with Application to Mapping Mars Returned Samples

Science.gov (United States)

Burton, A. S.; Berger, E. L.; Locke, D. R.; Lewis, E. K.; Moore, J. F.

2018-04-01

Laser microprobe of surfaces utilizing a two laser setup whereby the desorption laser threshold is lowered below ionization, and the resulting neutral plume is examined using 157nm Vacuum Ultraviolet laser light for mass spec surface mapping.

MBARI Mapping AUV: A High-Resolution Deep Ocean Seafloor Mapping Capability

Science.gov (United States)

Caress, D. W.; Kirkwood, W. J.; Thomas, H.; McEwen, R.; Henthorn, R.; McGill, P.; Thompson, D.; Sibenac, M.; Jensen, S.; Shane, F.; Hamilton, A.

2005-05-01

The Monterey Bay Aquarium Research Institute (MBARI) is developing an autonomous seafloor mapping capability for deep ocean science applications. The MBARI Mapping AUV is a 0.53 m (21 in) diameter, 5.1 m (16.7 ft) long, Dorado-class vehicle designed to carry four mapping sonars. The primary sensor is a 200 kHz multibeam sonar producing swath bathymetry and sidescan. In addition, the vehicle carries 100 kHz and 410 kHz chirp sidescan sonars, and a 2-16 kHz sweep chirp subbottom profiler. Navigation and attitude data are obtained from an inertial navigation system (INS) incorporating a ring laser gyro and a 300 kHz Doppler velocity log (DVL). The vehicle also includes acoustic modem, ultra-short baseline navigation, and long-baseline navigation systems. The Mapping AUV is powered by 6 kWhr of Li-polymer batteries, providing expected mission duration of 12 hours at a typical speed of 1.5 m/s. All components of the vehicle are rated to 6000 m depth, allowing MBARI to conduct high-resolution mapping of the deep-ocean seafloor. The sonar package is also be mountable on ROV Ventana, allowing surveys at altitudes less than 20 m at topographically challenging sites. The vehicle was assembled and extensively tested during 2004; this year we are commencing operations for MBARI science projects while continuing the process of testing and integrating the complete suite of sensors and systems. MBARI is beginning to use this capability to observe the changing morphology of dynamic systems such as submarine canyons and active slumps, to map deep-water benthic habitats at resolutions comparable to ROV and submersible observations, to provide basemaps for ROV dives, and to provide high resolution bathymetry and subbottom profiles as part of a variety of projects requiring knowledge of the seafloor. We will present initial results from surveys in and around Monterey Canyon, including high resolution repeat surveys of four sites along the canyon axis.

Definition of a RACK1 Interaction Network in Drosophila melanogaster Using SWATH-MS.

Science.gov (United States)

Kuhn, Lauriane; Majzoub, Karim; Einhorn, Evelyne; Chicher, Johana; Pompon, Julien; Imler, Jean-Luc; Hammann, Philippe; Meignin, Carine

2017-07-05

Receptor for Activated protein C kinase 1 (RACK1) is a scaffold protein that has been found in association with several signaling complexes, and with the 40S subunit of the ribosome. Using the model organism Drosophila melanogaster , we recently showed that RACK1 is required at the ribosome for internal ribosome entry site (IRES)-mediated translation of viruses. Here, we report a proteomic characterization of the interactome of RACK1 in Drosophila S2 cells. We carried out Label-Free quantitation using both Data-Dependent and Data-Independent Acquisition (DDA and DIA, respectively) and observed a significant advantage for the Sequential Window Acquisition of all THeoretical fragment-ion spectra (SWATH) method, both in terms of identification of interactants and quantification of low abundance proteins. These data represent the first SWATH spectral library available for Drosophila and will be a useful resource for the community. A total of 52 interacting proteins were identified, including several molecules involved in translation such as structural components of the ribosome, factors regulating translation initiation or elongation, and RNA binding proteins. Among these 52 proteins, 15 were identified as partners by the SWATH strategy only. Interestingly, these 15 proteins are significantly enriched for the functions translation and nucleic acid binding. This enrichment reflects the engagement of RACK1 at the ribosome and highlights the added value of SWATH analysis. A functional screen did not reveal any protein sharing the interesting properties of RACK1, which is required for IRES-dependent translation and not essential for cell viability. Intriguingly however, 10 of the RACK1 partners identified restrict replication of Cricket paralysis virus (CrPV), an IRES-containing virus. Copyright © 2017 Kuhn et al.

Thermal Analysis and Microhardness Mapping in Hybrid Laser Welds in a Structural Steel

Science.gov (United States)

2003-01-01

conditions. Via the keyhole the laser beam brings about easier ignition of the arc, stabilization of the arc welding process, and penetration of the...with respect to the conventional GMAW or GTAW processes without the need for very close fit-up. This paper will compare an autogenous laser weld to a...UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP017864 TITLE: Thermal Analysis and Microhardness Mapping in Hybrid Laser

Mapping of lead, magnesium and copper accumulation in plant tissues by laser-induced breakdown spectroscopy and laser-ablation inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Kaiser, J. [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno (Czech Republic)], E-mail: kaiser@fme.vutbr.cz; Galiova, M.; Novotny, K.; Cervenka, R. [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Reale, L. [Faculty of Sciences, University of L' Aquila, Via Vetoio (Coppito 1), 67010 L' Aquila (Italy); Novotny, J.; Liska, M.; Samek, O. [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno (Czech Republic); Kanicky, V.; Hrdlicka, A. [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Stejskal, K.; Adam, V.; Kizek, R. [Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University of Agriculture and Forestry, Zemedelska 1, 613 00 Brno (Czech Republic)

2009-01-15

Laser-Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) were utilized for mapping the accumulation of Pb, Mg and Cu with a resolution up to 200 {mu}m in a up to cm x cm area of sunflower (Helianthus annuus L.) leaves. The results obtained by LIBS and LA-ICP-MS are compared with the outcomes from Atomic Absorption Spectrometry (AAS) and Thin-Layer Chromatography (TLC). It is shown that laser-ablation based analytical methods can substitute or supplement these techniques mainly in the cases when a fast multi-elemental mapping of a large sample area is needed.

MODIS/Aqua Aerosol 5-Min L2 Swath 10km V006

Data.gov (United States)

National Aeronautics and Space Administration — The MODIS/Aqua Aerosol 5-Min L2 Swath 10km (MYD04_L2) product continues to provide full global coverage of aerosol properties from the Dark Target (DT) and Deep Blue...

Smartphone snapshot mapping of skin chromophores under triple-wavelength laser illumination

Science.gov (United States)

Spigulis, Janis; Oshina, Ilze; Berzina, Anna; Bykov, Alexander

2017-09-01

Chromophore distribution maps are useful tools for skin malformation severity assessment and for monitoring of skin recovery after burns, surgeries, and other interactions. The chromophore maps can be obtained by processing several spectral images of skin, e.g., captured by hyperspectral or multispectral cameras during seconds or even minutes. To avoid motion artifacts and simplify the procedure, a single-snapshot technique for mapping melanin, oxyhemoglobin, and deoxyhemoglobin of in-vivo skin by a smartphone under simultaneous three-wavelength (448-532-659 nm) laser illumination is proposed and examined. Three monochromatic spectral images related to the illumination wavelengths were extracted from the smartphone camera RGB image data set with respect to crosstalk between the RGB detection bands. Spectral images were further processed accordingly to Beer's law in a three chromophore approximation. Photon absorption path lengths in skin at the exploited wavelengths were estimated by means of Monte Carlo simulations. The technique was validated clinically on three kinds of skin lesions: nevi, hemangiomas, and seborrheic keratosis. Design of the developed add-on laser illumination system, image-processing details, and the results of clinical measurements are presented and discussed.

Remote landslide mapping using a laser rangefinder binocular and GPS

Directory of Open Access Journals (Sweden)

M. Santangelo

2010-12-01

Full Text Available We tested a high-quality laser rangefinder binocular coupled with a GPS receiver connected to a Tablet PC running dedicated software to help recognize and map in the field recent rainfall-induced landslides. The system was tested in the period between March and April 2010, in the Monte Castello di Vibio area, Umbria, Central Italy. To test the equipment, we measured thirteen slope failures that were mapped previously during a visual reconnaissance field campaign conducted in February and March 2010. For reference, four slope failures were also mapped by walking the GPS receiver along the landslide perimeter. Comparison of the different mappings revealed that the geographical information obtained remotely for each landslide by the rangefinder binocular and GPS was comparable to the information obtained by walking the GPS around the landslide perimeter, and was superior to the information obtained through the visual reconnaissance mapping. Although our tests were not exhaustive, we maintain that the system is effective to map recent rainfall induced landslides in the field, and we foresee the possibility of using the same (or similar system to map landslides, and other geomorphological features, in other areas.

California State Waters Map Series: offshore of Refugio Beach, California

Science.gov (United States)

Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Krigsman, Lisa M.; Dieter, Bryan E.; Conrad, James E.; Greene, H. Gary; Seitz, Gordon G.; Endris, Charles A.; Sliter, Ray W.; Wong, Florence L.; Erdey, Mercedes D.; Gutierrez, Carlos I.; Yoklavich, Mary M.; East, Amy E.; Hart, Patrick E.; Johnson, Samuel Y.; Cochran, Susan A.

2015-01-01

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology.

California State Waters Map Series: offshore of San Francisco, California

Science.gov (United States)

Cochrane, Guy R.; Johnson, Samuel Y.; Dartnell, Peter; Greene, H. Gary; Erdey, Mercedes D.; Golden, Nadine E.; Hartwell, Stephen R.; Endris, Charles A.; Manson, Michael W.; Sliter, Ray W.; Kvitek, Rikk G.; Watt, Janet Tilden; Ross, Stephanie L.; Bruns, Terry R.; Cochrane, Guy R.; Cochran, Susan A.

2015-01-01

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology.

California State Waters Map Series: offshore of Pacifica, California

Science.gov (United States)

Edwards, Brian D.; Phillips, Eleyne L.; Dartnell, Peter; Greene, H. Gary; Bretz, Carrie K.; Kvitek, Rikk G.; Hartwell, Stephen R.; Johnson, Samuel Y.; Cochrane, Guy R.; Dieter, Bryan E.; Sliter, Ray W.; Ross, Stephanie L.; Golden, Nadine E.; Watt, Janet Tilden; Chinn, John L.; Erdey, Mercedes D.; Krigsman, Lisa M.; Manson, Michael W.; Endris, Charles A.; Cochran, Susan A.; Edwards, Brian D.

2015-01-01

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. 

Archive of side scan sonar and swath bathymetry data collected during USGS cruise 10CCT01 offshore of Cat Island, Gulf Islands National Seashore, Mississippi, March 2010

Science.gov (United States)

DeWitt, Nancy T.; Flocks, James G.; Pfeiffer, William R.; Wiese, Dana S.

2010-01-01

In March of 2010, the U.S. Geological Survey (USGS) conducted geophysical surveys east of Cat Island, Mississippi (fig. 1). The efforts were part of the USGS Gulf of Mexico Science Coordination partnership with the U.S. Army Corps of Engineers (USACE) to assist the Mississippi Coastal Improvements Program (MsCIP) and the Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazards Susceptibility Project by mapping the shallow geological stratigraphic framework of the Mississippi Barrier Island Complex. These geophysical surveys will provide the data necessary for scientists to define, interpret, and provide baseline bathymetry and seafloor habitat for this area and to aid scientists in predicting future geomorpholocial changes of the islands with respect to climate change, storm impact, and sea-level rise. Furthermore, these data will provide information for barrier island restoration, particularly in Camille Cut, and provide protection for the historical Fort Massachusetts. For more information refer to http://ngom.usgs.gov/gomsc/mscip/index.html. This report serves as an archive of the processed swath bathymetry and side scan sonar data (SSS). Data products herein include gridded and interpolated surfaces, surface images, and x,y,z data products for both swath bathymetry and side scan sonar imagery. Additional files include trackline maps, navigation files, GIS files, Field Activity Collection System (FACS) logs, and formal FGDC metadata. Scanned images of the handwritten FACS logs and digital FACS logs are also provided as PDF files. Refer to the Acronyms page for expansion of acronyms and abbreviations used in this report or hold the cursor over an acronym for a pop-up explanation. The USGS St. Petersburg Coastal and Marine Science Center assigns a unique identifier to each cruise or field activity. For example, 10CCT01 tells us the data were collected in 2010 for the Coastal Change and Transport (CCT) study and the data were collected during the first field

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.

Testing Suitability of Cell Cultures for SILAC-Experiments Using SWATH-Mass Spectrometry.

Science.gov (United States)

Reinders, Yvonne; Völler, Daniel; Bosserhoff, Anja-K; Oefner, Peter J; Reinders, Jörg

2016-01-01

Precise quantification is a major issue in contemporary proteomics. Both stable-isotope-labeling and label-free methods have been established for differential protein quantification and both approaches have different advantages and disadvantages. The present protocol uses the superior precision of label-free SWATH-mass spectrometry to test for suitability of cell lines for a SILAC-labeling approach as systematic regulations may be introduced upon incorporation of the "heavy" amino acids. The SILAC-labeled cell cultures can afterwards be used for further analyses where stable-isotope-labeling is mandatory or has substantial advantages over label-free approaches such as pulse-chase-experiments and differential protein interaction analyses based on co-immunoprecipitation. As SWATH-mass spectrometry avoids the missing-value-problem typically caused by undersampling in highly complex samples and shows superior precision for the quantification, it is better suited for the detection of systematic changes caused by the SILAC-labeling and thus, can serve as a useful tool to test cell lines for changes upon SILAC-labeling.

California State Waters Map Series: offshore of Tomales Point, California

Science.gov (United States)

Johnson, Samuel Y.; Dartnell, Peter; Golden, Nadine E.; Hartwell, Stephen R.; Greene, H. Gary; Erdey, Mercedes D.; Cochrane, Guy R.; Watt, Janet Tilden; Kvitek, Rikk G.; Manson, Michael W.; Endris, Charles A.; Dieter, Bryan E.; Krigsman, Lisa M.; Sliter, Ray W.; Lowe, Erik N.; Chinn, John L.; Johnson, Samuel Y.; Cochran, Susan A.

2015-01-01

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 200 m) subsurface geology.

Powder densification maps in Selective Laser Sintering

International Nuclear Information System (INIS)

Bourell, D.; Wohlert, M.; Harlan, N.; Beaman, J.; Das, S.

2002-01-01

Selective Laser Sintering (SLS) is a manufacturing process in which a part is produced without the need for part-specific tooling. It competes effectively with other manufacturing processes when part geometry is complex and the production run is not large. Traditionally, this was limited to prototype production, although tooling applications are now appearing. This paper describes several applications of powder densification maps to advance solutions in direct SLS of metallic and ceramic powders. Time-dependent plasticity issues arise in pre-processing of powder to make it suitable for SLS and in post-processing of SLS parts to obtain desired density. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

Mapping GPS Multipath: a Case Study for the Lunar Laser Ranger ...

African Journals Online (AJOL)

Cilence Munghemezulu

Mapping GPS Multipath: a Case Study for the Lunar Laser .... assess the level of multipath in the vicinity of the GNSS antenna by making use of ..... navigation in urban environment', Indian Journal of Radio and Space Physics, vol. ... Torrence C & Compo GP 1998, 'A practical guide to wavelet Analysis', Bulletin of the ...

MODIS/Aqua Raw Radiances in Counts 5-Min L1A Swath V006

Data.gov (United States)

National Aeronautics and Space Administration — The MODIS/Aqua Raw Radiances in Counts 5-Min L1A Swath (MYD01) product contains reformatted and packaged raw instrument data. MODIS instrument data, in packetized...

Return-map for low-frequency fluctuations in semiconductor lasers with optical feedback

DEFF Research Database (Denmark)

Mørk, Jesper; Sabbatier, H.; Sørensen, Mads Peter

1999-01-01

We show that the phenomenon of low-frequency fluctuations (LFF) , commonly observed in semiconductor lasers with optical feedback, can be explained by a simple return-map, implying a tremendous simplification in the description of the slow time-scale dynamics of the system. Experimentally observed...

Laser ablation of polymer coatings allows for electromagnetic field enhancement mapping around nanostructures

DEFF Research Database (Denmark)

Fiutowski, Jacek; Maibohm, Christian; Kjelstrup-Hansen, Jakob

2011-01-01

Subdiffraction spatially resolved, quantitative mapping of strongly localized field intensity enhancement on gold nanostructures via laser ablation of polymer thin films is reported. Illumination using a femtosecond laser scanning microscope excites surface plasmons in the nanostructures....... The accompanying field enhancement substantially lowers the ablation threshold of the polymer film and thus creates local ablation spots and corresponding topographic modifications of the polymer film. Such modifications are quantified straightforwardly via scanning electron microscopy and atomic force microscopy...

MODIS/Terra Calibrated Radiances 5-Min L1B Swath 1km V006

Data.gov (United States)

National Aeronautics and Space Administration — The MODIS/Terra Calibrated Radiances 5-Min L1B Swath 1km (MOD021KM) contains calibrated and geolocated at-aperture radiances for 36 discrete bands located in the 0.4...

Laser-Based Slam with Efficient Occupancy Likelihood Map Learning for Dynamic Indoor Scenes

Science.gov (United States)

Li, Li; Yao, Jian; Xie, Renping; Tu, Jinge; Feng, Chen

2016-06-01

Location-Based Services (LBS) have attracted growing attention in recent years, especially in indoor environments. The fundamental technique of LBS is the map building for unknown environments, this technique also named as simultaneous localization and mapping (SLAM) in robotic society. In this paper, we propose a novel approach for SLAMin dynamic indoor scenes based on a 2D laser scanner mounted on a mobile Unmanned Ground Vehicle (UGV) with the help of the grid-based occupancy likelihood map. Instead of applying scan matching in two adjacent scans, we propose to match current scan with the occupancy likelihood map learned from all previous scans in multiple scales to avoid the accumulation of matching errors. Due to that the acquisition of the points in a scan is sequential but not simultaneous, there unavoidably exists the scan distortion at different extents. To compensate the scan distortion caused by the motion of the UGV, we propose to integrate a velocity of a laser range finder (LRF) into the scan matching optimization framework. Besides, to reduce the effect of dynamic objects such as walking pedestrians often existed in indoor scenes as much as possible, we propose a new occupancy likelihood map learning strategy by increasing or decreasing the probability of each occupancy grid after each scan matching. Experimental results in several challenged indoor scenes demonstrate that our proposed approach is capable of providing high-precision SLAM results.

Mapping the seabed and habitats in National Marine Sanctuaries - Examples from the East, Gulf and West Coasts

Science.gov (United States)

Valentine, Page C.; Cochrane, Guy R.; Scanlon, Kathryn M.

2003-01-01

The National Marine Sanctuary System requires seabed and habitat maps to serve as a basis for managing sanctuary resources and for conducting research. NOAA, the agency that manages the sanctuaries, and the USGS have conducted mapping projects in three sanctuaries (Stellwagen Bank NMS, Flower Garden Banks NMS, and Channel Islands NMS) with an emphasis on collaboration of geologists and biologists from the two agencies and from academic institutions. Mapping of seabed habitats is a developing field that requires the integration of geologic and biologic studies and the use of swath imaging techniques such as multibeam and sidescan sonar. Major products of swath mapping are shaded-relief topographic imagery which shows seabed features in great detail, and backscatter imagery which provides an indication of the types of materials that constitute the seabed. Sea floor images provide an excellent basis for conducting the groundtruthing studies (using video, photo, and sampling techniques) that are required to collect the data necessary for making meaningful interpretative maps of the seabed. The compilation of interpretive maps showing seabed environments and habitats also requires the development of a sea floor classification system that will be a basis for comparing, managing, and researching characteristic areas of the seabed. Seabed maps of the sanctuaries are proving useful for management and research decisions that address commercial and recreational fishing, habitat disturbance, engineering projects, tourism, and cultural resources.

[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.

Possibilities of a Personal Laser Scanning System for Forest Mapping and Ecosystem Services

Science.gov (United States)

Liang, Xinlian; Kukko, Antero; Kaartinen, Harri; Hyyppä, Juha; Yu, Xiaowei; Jaakkola, Anttoni; Wang, Yunsheng

2014-01-01

A professional-quality, personal laser scanning (PLS) system for collecting tree attributes was demonstrated in this paper. The applied system, which is wearable by human operators, consists of a multi-constellation navigation system and an ultra-high-speed phase-shift laser scanner mounted on a rigid baseplate and consisting of a single sensor block. A multipass-corridor-mapping method was developed to process PLS data and a 2,000 m2 forest plot was utilized in the test. The tree stem detection accuracy was 82.6%; the root mean square error (RMSE) of the estimates of tree diameter at breast height (DBH) was 5.06 cm; the RMSE of the estimates of tree location was 0.38 m. The relative RMSE of the DBH estimates was 14.63%. The results showed, for the first time, the potential of the PLS system in mapping large forest plots. Further research on mapping accuracy in various forest conditions, data correction methods and multi-sensoral positioning techniques is needed. The utilization of this system in different applications, such as harvester operations, should also be explored. In addition to collecting tree-level and plot-level data for forest inventory, other possible applications of PLS for forest ecosystem services include mapping of canopy gaps, measuring leaf area index of large areas, documenting and visualizing forest routes feasible for recreation, hiking and berry and mushroom picking. PMID:24434879

Swath bathymetric investigation of the seamounts located in the Laxmi Basin, eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Bhattacharya, G.C.; Murty, G.P.S.; Srinivas, K.; Chaubey, A.K.; Sudhakar, T.; Nair, R.R.

Multibeam (hydrosweep) swath bathymetric investigations revealed the presence of a NNW trending linear seamount chain along the axial part of the Laxmi Basin in the eastern Arabian Sea, between 15~'N, 70~'15'E and 17~'20'N, 69~'E. This chain...

Application of terrestrial laser scanning to the development and updating of the base map

Directory of Open Access Journals (Sweden)

Klapa Przemysław

2017-06-01

Full Text Available The base map provides basic information about land to individuals, companies, developers, design engineers, organizations, and government agencies. Its contents include spatial location data for control network points, buildings, land lots, infrastructure facilities, and topographic features. As the primary map of the country, it must be developed in accordance with specific laws and regulations and be continuously updated. The base map is a data source used for the development and updating of derivative maps and other large scale cartographic materials such as thematic or topographic maps. Thanks to the advancement of science and technology, the quality of land surveys carried out by means of terrestrial laser scanning (TLS matches that of traditional surveying methods in many respects.

Technology Development for 3-D Wide Swath Imaging Supporting ACE

Science.gov (United States)

Racette, Paul; Heymsfield, Gerry; Li, Lihua; Mclinden, Matthew; Park, Richard; Cooley, Michael; Stenger, Pete; Hand, Thomas

2014-01-01

The National Academy of Sciences Decadal Survey (DS) Aerosol-Cloud-Ecosystems Mission (ACE) aims to advance our ability to observe and predict changes to the Earth's hydrological cycle and energy balance in response to climate forcing, especially those changes associated with the effects of aerosol on clouds and precipitation. ACE is focused on obtaining measurements to reduce the uncertainties in current climate models arising from the lack in understanding of aerosol-cloud interactions. As part of the mission instrument suite, a dual-frequency radar comprised of a fixed-beam 94 gigahertz (W-band) radar and a wide-swath 35 gigahertz (Ka-band) imaging radar has been recommended by the ACE Science Working Group.In our 2010 Instrument Incubator Program project, we've developed a radar architecture that addresses the challenge associated with achieving the measurement objectives through an innovative, shared aperture antenna that allows dual-frequency radar operation while achieving wide-swath (100 kilometers) imaging at Ka-band. The antenna system incorporates 2 key technologies; a) a novel dual-band reflectorreflectarray and b) a Ka-band Active Electronically Scanned Array (AESA) feed module. The dual-band antenna is comprised of a primary cylindrical reflectorreflectarray surface illuminated by a point-focus W-band feed (compatible with a quasi-optical beam waveguide feed, such as that employed on CloudSat); the Ka-band AESA line feed provides wide-swath across-track scanning. The benefits of this shared-aperture approach include significant reductions in ACE satellite payload size, weight, and cost, as compared to a two aperture approach. Four objectives were addressed in our project. The first entailed developing the tools for the analysis and design of reflectarray antennas, assessment of candidate reflectarray elements, and validation using test coupons. The second objective was to develop a full-scale aperture design utilizing the reflectarray surface and to

MODIS/Aqua Clouds 5-Min L2 Swath 1km and 5km V006

Data.gov (United States)

National Aeronautics and Space Administration — The MODIS/Aqua Clouds 5-Min L2 Swath 1km and 5km (MYD06_L2) product consists of cloud optical and physical parameters. These parameters are derived using remotely...

Precise mapping of annual river bed changes based on airborne laser bathymetry

Science.gov (United States)

Mandlburger, Gottfried; Wieser, Martin; Pfeifer, Norbert; Pfennigbauer, Martin; Steinbacher, Frank; Aufleger, Markus

2014-05-01

Airborne Laser Bathymtery (ALB) is a method for capturing relatively shallow water bodies from the air using a pulsed green laser (wavelength=532nm). While this technique was first used for mapping coastal waters only, recent progress in sensor technology has opened the field to apply ALB to running inland waters. Especially for alpine rivers the precise mapping of the channel topography is a challenging task as the flow velocities are often high and the area is difficult and/or dangerous to access by boat or by feet. Traditional mapping techniques like tachymetry or echo sounding fail in such situations while ALB provides, both, high spot position accuracy in the cm range and high spatial resolution in the dm range. Furthermore, state-of-the-art ALB systems allow simultaneous mapping of the river bed and the riparian area and, therefore, represent a comprehensive and efficient technology for mapping the entire floodplain area. The maximum penetration depth depends on, both, water turbidity and bottom reflectivity. Consequently, ALB provides the highest accuracy and resolution over bright gravel rivers with relatively clear water. We demonstrate the capability of ALB for precise mapping of river bed changes based on three flight campaigns in April, May and October 2013 at the River Pielach (Lower Austria) carried out with Riegl's VQ-820-G topo-bathymetric laser scanner. Operated at a flight height of 600m above ground with a pulse repetition rate of 510kHz (effective measurement rate 200kHz) this yielded a mean point spacing within the river bed of 20cm (i.e. point density: 25 points/m2). The positioning accuracy of the river bed points is approx. 2-5cm and depends on the overall ranging precision (20mm), the quality of the water surface model (derived from the ALB point cloud), and the signal intensity (decreasing with water depth). All in all, the obtained point cloud allowed the derivation of a dense grid model of the channel topography (0.25m cell size) for all

Possibilities of a Personal Laser Scanning System for Forest Mapping and Ecosystem Services

Directory of Open Access Journals (Sweden)

Xinlian Liang

2014-01-01

Full Text Available A professional-quality, personal laser scanning (PLS system for collecting tree attributes was demonstrated in this paper. The applied system, which is wearable by human operators, consists of a multi-constellation navigation system and an ultra-high-speed phase-shift laser scanner mounted on a rigid baseplate and consisting of a single sensor block. A multipass-corridor-mapping method was developed to process PLS data and a 2,000 m2 forest plot was utilized in the test. The tree stem detection accuracy was 82.6%; the root mean square error (RMSE of the estimates of tree diameter at breast height (DBH was 5.06 cm; the RMSE of the estimates of tree location was 0.38 m. The relative RMSE of the DBH estimates was 14.63%. The results showed, for the first time, the potential of the PLS system in mapping large forest plots. Further research on mapping accuracy in various forest conditions, data correction methods and multi-sensoral positioning techniques is needed. The utilization of this system in different applications, such as harvester operations, should also be explored. In addition to collecting tree-level and plot-level data for forest inventory, other possible applications of PLS for forest ecosystem services include mapping of canopy gaps, measuring leaf area index of large areas, documenting and visualizing forest routes feasible for recreation, hiking and berry and mushroom picking.

Mapping the Topography of Mercury with MESSENGER Laser Altimetry

Science.gov (United States)

Sun, Xiaoli; Cavanaugh, John F.; Neumann, Gregory A.; Smith, David E..; Zubor, Maria T.

2012-01-01

The Mercury Laser Altimeter onboard MESSENGER involves unique design elements that deal with the challenges of being in orbit around Mercury. The Mercury Laser Altimeter (MLA) is one of seven instruments on NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. MESSENGER was launched on 3 August 2004, and entered into orbit about Mercury on 18 March 2011 after a journey through the inner solar system. This involved six planetary flybys, including three of Mercury. MLA is designed to map the topography and landforms of Mercury's surface. It also measures the planet's forced libration (motion about the spin axis), which helps constrain the state of the core. The first science measurements from orbit taken with MLA were made on 29 March 2011 and continue to date. MLA had accumulated about 8.3 million laser ranging measurements to Mercury's surface, as of 31 July 2012, i.e., over six Mercury years (528 Earth days). Although MLA is the third planetary lidar built at the NASA Goddard Space Flight Center (GSFC), MLA must endure a much harsher thermal environment near Mercury than the previous instruments on Mars and Earth satellites. The design of MLA was derived in part from that of the Mars Orbiter Laser Altimeter on Mars Global Surveyor. However, MLA must range over greater distances and often in off-nadir directions from a highly eccentric orbit. In MLA we use a single-mode diode-pumped Nd:YAG (neodymium-doped yttrium aluminum garnet) laser that is highly collimated to maintain a small footprint on the planet. The receiver has both a narrow field of view and a narrow spectral bandwidth to minimize the amount of background light detected from the sunlit hemisphere of Mercury. We achieve the highest possible receiver sensitivity by employing the minimum receiver detection threshold.

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.)

Application of terrestrial laser scanning to the development and updating of the base map

Science.gov (United States)

Klapa, Przemysław; Mitka, Bartosz

2017-06-01

The base map provides basic information about land to individuals, companies, developers, design engineers, organizations, and government agencies. Its contents include spatial location data for control network points, buildings, land lots, infrastructure facilities, and topographic features. As the primary map of the country, it must be developed in accordance with specific laws and regulations and be continuously updated. The base map is a data source used for the development and updating of derivative maps and other large scale cartographic materials such as thematic or topographic maps. Thanks to the advancement of science and technology, the quality of land surveys carried out by means of terrestrial laser scanning (TLS) matches that of traditional surveying methods in many respects. This paper discusses the potential application of output data from laser scanners (point clouds) to the development and updating of cartographic materials, taking Poland's base map as an example. A few research sites were chosen to present the method and the process of conducting a TLS land survey: a fragment of a residential area, a street, the surroundings of buildings, and an undeveloped area. The entire map that was drawn as a result of the survey was checked by comparing it to a map obtained from PODGiK (pol. Powiatowy Ośrodek Dokumentacji Geodezyjnej i Kartograficznej - Regional Centre for Geodetic and Cartographic Records) and by conducting a field inspection. An accuracy and quality analysis of the conducted fieldwork and deskwork yielded very good results, which provide solid grounds for predicating that cartographic materials based on a TLS point cloud are a reliable source of information about land. The contents of the map that had been created with the use of the obtained point cloud were very accurately located in space (x, y, z). The conducted accuracy analysis and the inspection of the performed works showed that high quality is characteristic of TLS surveys. The

Airborne 3D Imaging Lidar for Contiguous Decimeter Resolution Terrain Mapping and Shallow Water Bathymetry

Science.gov (United States)

Degnan, J. J.; Wells, D. N.; Huet, H.; Chauvet, N.; Lawrence, D. W.; Mitchell, S. E.; Eklund, W. D.

2005-12-01

A 3D imaging lidar system, developed for the University of Florida at Gainesville and operating at the water transmissive wavelength of 532 nm, is designed to contiguously map underlying terrain and/or perform shallow water bathymetry on a single overflight from an altitude of 600 m with a swath width of 225 m and a horizontal spatial resolution of 20 cm. Each 600 psec pulse from a frequency-doubled, low power (~3 microjoules @ 8 kHz = 24 mW), passively Q-switched Nd:YAG microchip laser is passed through a holographic element which projects a 10x10 array of spots onto a 2m x 2m target area. The individual ground spots are then imaged onto individual anodes within a 10x10 segmented anode photomultiplier. The latter is followed by a 100 channel multistop ranging receiver with a range resolution of about 4 cm. The multistop feature permits single photon detection in daylight with wide range gates as well as multiple single photon returns per pixel per laser fire from volumetric scatterers such as tree canopies or turbid water columns. The individual single pulse 3D images are contiguously mosaiced together through the combined action of the platform velocity and a counter-rotating dual wedge optical scanner whose rotations are synchronized to the laser pulse train. The paper provides an overview of the lidar opto-mechanical design, the synchronized dual wedge scanner and servo controller, and the experimental results obtained to date.

Synchronized renal blood flow dynamics mapped with wavelet analysis of laser speckle flowmetry data

DEFF Research Database (Denmark)

Brazhe, Alexey R; Marsh, Donald J; von Holstein-Rathlou, Niels-Henrik

2014-01-01

of rat kidneys. The regulatory mechanism in the renal microcirculation generates oscillations in arterial blood flow at several characteristic frequencies. Our approach to laser speckle image processing allows detection of frequency and phase entrainments, visualization of their patterns, and estimation......Full-field laser speckle microscopy provides real-time imaging of superficial blood flow rate. Here we apply continuous wavelet transform to time series of speckle-estimated blood flow from each pixel of the images to map synchronous patterns in instantaneous frequency and phase on the surface...... of the extent of synchronization in renal cortex dynamics....

Mapping of elements at risk for landslides in the tropics using airborne laser scanning

NARCIS (Netherlands)

Razak, Khamarrul Azahari; van Westen, C.J.; Straatsma, Menno; ... [et al.],

2011-01-01

Mapping elements at risk for landslides in the tropics pose as a challenging task. Aerial-photograph, satellite imagery, and synthetic perture radar images are less effective to accurately provide physical presence of objects in a relatively short time. In this paper, we utilized an airborne laser

Coseismic slip in the 2010 Yushu earthquake (China, constrained by wide-swath and strip-map InSAR

Directory of Open Access Journals (Sweden)

Y. Wen

2013-01-01

Full Text Available On 14 April 2010, an M_w = 6.9 earthquake occurred in the Yushu county of China, which caused ~3000 people to lose their lives. Integrated with the information from the observed surface ruptures and aftershock locations, the faulting pattern of this earthquake is derived from the descending wide-swath and ascending strip mode PALSAR data collected by ALOS satellite. We used a layered crustal model and stress drop smoothing constraint to infer the coseismic slip distribution. Our model suggests that the earthquake fault can be divided into four segments and the slip mainly occurs within the upper 12 km with a maximum slip of 2.0 m at depth of 3 km on the Jiegu segment. The rupture of the upper 12 km is dominated by left-lateral strike-slip motion. The relatively small slip along the SE region of Yushu segment suggests a slip deficit there. The inverted geodetic moment is approximately M_w = 6.9, consistent with the seismological results. The average stress drop caused by the earthquake is about 2 MPa with a maximum stress drop of 8.3 MPa. Furthermore, the calculated static Coulomb stress changes in surrounding regions show increased Coulomb stress occurred in the SE region along the Yushu segment but with less aftershock, indicating an increased seismic hazard in this region after the earthquake.

MODIS/Aqua Temperature and Water Vapor Profiles 5-Min L2 Swath 5km V006

Data.gov (United States)

National Aeronautics and Space Administration — MODIS/Aqua Temperature and Water Vapor Profiles 5-Min L2 Swath 5km (MYD07_L2). MODIS was launched aboard the Aqua satellite on May 04, 2002 (1:30 pm equator crossing...

OMPS/NPP PCA SO2 Total Column 1-Orbit L2 Swath 50x50km NRT

Data.gov (United States)

National Aeronautics and Space Administration — The OMPS-NPP L2 NM Sulfur Dioxide (SO2) Total and Tropospheric Column swath orbital collection 2 version 2.0 product contains the retrieved sulfur dioxide (SO2)...

Mapping Ross Ice Shelf with ROSETTA-Ice airborne laser altimetry

Science.gov (United States)

Becker, M. K.; Fricker, H. A.; Padman, L.; Bell, R. E.; Siegfried, M. R.; Dieck, C. C. M.

2017-12-01

The Ross Ocean and ice Shelf Environment and Tectonic setting Through Aerogeophysical surveys and modeling (ROSETTA-Ice) project combines airborne glaciological, geological, and oceanographic observations to enhance our understanding of the history and dynamics of the large ( 500,000 square km) Ross Ice Shelf (RIS). Here, we focus on the Light Detection And Ranging (LiDAR) data collected in 2015 and 2016. This data set represents a significant advance in resolution: Whereas the last attempt to systematically map RIS (the surface-based RIGGS program in the 1970s) was at 55 km grid spacing, the ROSETTA-Ice grid has 10-20 km line spacing and much higher along-track resolution. We discuss two different strategies for processing the raw LiDAR data: one that requires proprietary software (Riegl's RiPROCESS package), and one that employs open-source programs and libraries. With the processed elevation data, we are able to resolve fine-scale ice-shelf features such as the "rampart-moat" ice-front morphology, which has previously been observed on and modeled for icebergs. This feature is also visible in the ROSETTA-Ice shallow-ice radar data; comparing the laser data with radargrams provides insight into the processes leading to their formation. Near-surface firn state and total firn air content can also be investigated through combined analysis of laser altimetry and radar data. By performing similar analyses with data from the radar altimeter aboard CryoSat-2, we demonstrate the utility of the ROSETTA-Ice LiDAR data set in satellite validation efforts. The incorporation of the LiDAR data from the third and final field season (December 2017) will allow us to construct a DEM and an ice thickness map of RIS for the austral summers of 2015-2017. These products will be used to validate and extend observations of height changes from satellite radar and laser altimetry, as well as to update regional models of ocean circulation and ice dynamics.

Geodetic Imaging for Rapid Assessment of Earthquakes: Airborne Laser Scanning (ALS)

Science.gov (United States)

Carter, W. E.; Shrestha, R. L.; Glennie, C. L.; Sartori, M.; Fernandez-Diaz, J.; National CenterAirborne Laser Mapping Operational Center

2010-12-01

To the residents of an area struck by a strong earthquake quantitative information on damage to the infrastructure, and its attendant impact on relief and recovery efforts, is urgent and of primary concern. To earth scientists a strong earthquake offers an opportunity to learn more about earthquake mechanisms, and to compare their models with the real world, in hopes of one day being able to accurately predict the precise locations, magnitudes, and times of large (and potentially disastrous) earthquakes. Airborne laser scanning (also referred to as airborne LiDAR or Airborne Laser Swath Mapping) is particularly well suited for rapid assessment of earthquakes, both for immediately estimating the damage to infrastructure and for providing information for the scientific study of earthquakes. ALS observations collected at low altitude (500—1000m) from a relatively slow (70—100m/sec) aircraft can provide dense (5—15 points/m2) sets of surface features (buildings, vegetation, ground), extending over hundreds of square kilometers with turn around times of several hours to a few days. The actual response time to any given event depends on several factors, including such bureaucratic issues as approval of funds, export license formalities, and clearance to fly over the area to be mapped, and operational factors such as the deployment of the aircraft and ground teams may also take a number of days for remote locations. Of course the need for immediate mapping of earthquake damage generally is not as urgent in remote regions with less infrastructure and few inhabitants. During August 16-19, 2010 the National Center for Airborne Laser Mapping (NCALM) mapped the area affected by the magnitude 7.2 El Mayor-Cucapah Earthquake (Northern Baja California Earthquake), which occurred on April 4, 2010, and was felt throughout southern California, Arizona, Nevada, and Baja California North, Mexico. From initial ground observations the fault rupture appeared to extend 75 km

Archive of Side Scan Sonar and Swath Bathymetry Data collected during USGS Cruise 10CCT02 Offshore of Petit Bois Island Including Petit Bois Pass, Gulf Islands National Seashore, Mississippi, March 2010

Science.gov (United States)

Pfeiffer, William R.; Flocks, James G.; DeWitt, Nancy T.; Forde, Arnell S.; Kelso, Kyle; Thompson, Phillip R.; Wiese, Dana S.

2011-01-01

In March of 2010, the U.S. Geological Survey (USGS) conducted geophysical surveys offshore of Petit Bois Island, Mississippi, and Dauphin Island, Alabama (fig. 1). These efforts were part of the USGS Gulf of Mexico Science Coordination partnership with the U.S. Army Corps of Engineers (USACE) to assist the Mississippi Coastal Improvements Program (MsCIP) and the Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazards Susceptibility Project by mapping the shallow geologic stratigraphic framework of the Mississippi Barrier Island Complex. These geophysical surveys will provide the data necessary for scientists to define, interpret, and provide baseline bathymetry and seafloor habitat for this area and to aid scientists in predicting future geomorphological changes of the islands with respect to climate change, storm impact, and sea-level rise. Furthermore, these data will provide information for barrier island restoration, particularly in Camille Cut, and protection for the historical Fort Massachusetts on Ship Island, Mississippi. For more information please refer to http://ngom.usgs.gov/gomsc/mscip/index.html. This report serves as an archive of the processed swath bathymetry and side scan sonar data (SSS). Data products herein include gridded and interpolated surfaces, seabed backscatter images, and ASCII x,y,z data products for both swath bathymetry and side scan sonar imagery. Additional files include trackline maps, navigation files, GIS files, Field Activity Collection System (FACS) logs, and formal FGDC metadata. Scanned images of the handwritten and digital FACS logs are also provided as PDF files. Refer to the Acronyms page for expansion of acronyms and abbreviations used in this report.

Geomorphometric analysis of cave ceiling channels mapped with 3-D terrestrial laser scanning

Science.gov (United States)

Gallay, Michal; Hochmuth, Zdenko; Kaňuk, Ján; Hofierka, Jaroslav

2016-05-01

The change of hydrological conditions during the evolution of caves in carbonate rocks often results in a complex subterranean geomorphology, which comprises specific landforms such as ceiling channels, anastomosing half tubes, or speleothems organized vertically in different levels. Studying such complex environments traditionally requires tedious mapping; however, this is being replaced with terrestrial laser scanning technology. Laser scanning overcomes the problem of reaching high ceilings, providing new options to map underground landscapes with unprecedented level of detail and accuracy. The acquired point cloud can be handled conveniently with dedicated software, but applying traditional geomorphometry to analyse the cave surface is limited. This is because geomorphometry has been focused on parameterization and analysis of surficial terrain. The theoretical and methodological concept has been based on two-dimensional (2-D) scalar fields, which are sufficient for most cases of the surficial terrain. The terrain surface is modelled with a bivariate function of altitude (elevation) and represented by a raster digital elevation model. However, the cave is a 3-D entity; therefore, a different approach is required for geomorphometric analysis. In this paper, we demonstrate the benefits of high-resolution cave mapping and 3-D modelling to better understand the palaeohydrography of the Domica cave in Slovakia. This methodological approach adopted traditional geomorphometric methods in a unique manner and also new methods used in 3-D computer graphics, which can be applied to study other 3-D geomorphological forms.

GEOMETRIC QUALITY ASSESSMENT OF LIDAR DATA BASED ON SWATH OVERLAP

Directory of Open Access Journals (Sweden)

A. Sampath

2016-06-01

Full Text Available This paper provides guidelines on quantifying the relative horizontal and vertical errors observed between conjugate features in the overlapping regions of lidar data. The quantification of these errors is important because their presence quantifies the geometric quality of the data. A data set can be said to have good geometric quality if measurements of identical features, regardless of their position or orientation, yield identical results. Good geometric quality indicates that the data are produced using sensor models that are working as they are mathematically designed, and data acquisition processes are not introducing any unforeseen distortion in the data. High geometric quality also leads to high geolocation accuracy of the data when the data acquisition process includes coupling the sensor with geopositioning systems. Current specifications (e.g. Heidemann 2014 do not provide adequate means to quantitatively measure these errors, even though they are required to be reported. Current accuracy measurement and reporting practices followed in the industry and as recommended by data specification documents also potentially underestimate the inter-swath errors, including the presence of systematic errors in lidar data. Hence they pose a risk to the user in terms of data acceptance (i.e. a higher potential for Type II error indicating risk of accepting potentially unsuitable data. For example, if the overlap area is too small or if the sampled locations are close to the center of overlap, or if the errors are sampled in flat regions when there are residual pitch errors in the data, the resultant Root Mean Square Differences (RMSD can still be small. To avoid this, the following are suggested to be used as criteria for defining the inter-swath quality of data: a Median Discrepancy Angle b Mean and RMSD of Horizontal Errors using DQM measured on sloping surfaces c RMSD for sampled locations from flat areas (defined as areas with less than 5

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)

MODIS/Aqua Clear Radiance Statistics Indexed to Global Grid 5-Min L2 Swath 10km V006

Data.gov (United States)

National Aeronautics and Space Administration — The MODIS/Aqua Clear Radiance Statistics Indexed to Global Grid 5-Min L2 Swath 10km (MYDCSR_G) provides a variety of statistical measures that characterize observed...

Small ships don't shine: classification of ocean vessels from low resolution, large swath area SAR acquisitions

CSIR Research Space (South Africa)

Meyer, Rory GV

2016-07-01

Full Text Available the Understanding of Our Living Planet, 10-15 July 2016, Beijing, China Small ships don't shine: Classification of ocean vessels from low resolution, large swath area SAR acquisitions R. G. V. Meyer ; W. Kleynhans ; C. P. Schwegmann Abstract: Monitoring...

Highly dissipative Hénon map behavior in the four-level model of the CO 2 laser with modulated losses

Science.gov (United States)

Pando L., C. L.; Acosta, G. A. Luna; Meucci, R.; Ciofini, M.

1995-02-01

We show that the four-level model for the CO 2 laser with modulated losses behaves in a qualitatively similar way as the highly dissipative Hénon map. The ubiquity of elements of the universal sequence, their related symbolic dynamics, and the presence of reverse bifurcations of chaotic bands in the model are reminiscent of the logistic map which is the limit of the Hénon map when the Jacobian equals zero. The coexistence of attractors, its dynamics related to contraction of volumes in phase space and the associated return maps can be correlated with those of the highly dissipative Hénon map.

Laser electro-optic system for rapid three-dimensional /3-D/ topographic mapping of surfaces

Science.gov (United States)

Altschuler, M. D.; Altschuler, B. R.; Taboada, J.

1981-01-01

It is pointed out that the generic utility of a robot in a factory/assembly environment could be substantially enhanced by providing a vision capability to the robot. A standard videocamera for robot vision provides a two-dimensional image which contains insufficient information for a detailed three-dimensional reconstruction of an object. Approaches which supply the additional information needed for the three-dimensional mapping of objects with complex surface shapes are briefly considered and a description is presented of a laser-based system which can provide three-dimensional vision to a robot. The system consists of a laser beam array generator, an optical image recorder, and software for controlling the required operations. The projection of a laser beam array onto a surface produces a dot pattern image which is viewed from one or more suitable perspectives. Attention is given to the mathematical method employed, the space coding technique, the approaches used for obtaining the transformation parameters, the optics for laser beam array generation, the hardware for beam array coding, and aspects of image acquisition.

The Surge, Wave, and Tide Hydrodynamics (SWaTH) network of the U.S. Geological Survey—Past and future implementation of storm-response monitoring, data collection, and data delivery

Science.gov (United States)

Verdi, Richard J.; Lotspeich, R. Russell; Robbins, Jeanne C.; Busciolano, Ronald J.; Mullaney, John R.; Massey, Andrew J.; Banks, William S.; Roland, Mark A.; Jenter, Harry L.; Peppler, Marie C.; Suro, Thomas P.; Schubert, Christopher E.; Nardi, Mark R.

2017-06-20

After Hurricane Sandy made landfall along the northeastern Atlantic coast of the United States on October 29, 2012, the U.S. Geological Survey (USGS) carried out scientific investigations to assist with protecting coastal communities and resources from future flooding. The work included development and implementation of the Surge, Wave, and Tide Hydrodynamics (SWaTH) network consisting of more than 900 monitoring stations. The SWaTH network was designed to greatly improve the collection and timely dissemination of information related to storm surge and coastal flooding. The network provides a significant enhancement to USGS data-collection capabilities in the region impacted by Hurricane Sandy and represents a new strategy for observing and monitoring coastal storms, which should result in improved understanding, prediction, and warning of storm-surge impacts and lead to more resilient coastal communities.As innovative as it is, SWaTH evolved from previous USGS efforts to collect storm-surge data needed by others to improve storm-surge modeling, warning, and mitigation. This report discusses the development and implementation of the SWaTH network, and some of the regional stories associated with the landfall of Hurricane Sandy, as well as some previous events that informed the SWaTH development effort. Additional discussions on the mechanics of inundation and how the USGS is working with partners to help protect coastal communities from future storm impacts are also included.

Velocity map imaging of attosecond and femtosecond dynamics in atoms and small molecules in strong laser fields

International Nuclear Information System (INIS)

Kling, M.F.; Ni, Yongfeng; Lepine, F.; Khan, J.I.; Vrakking, M.J.J.; Johnsson, P.; Remetter, T.; Varju, K.; Gustafsson, E.; L'Huillier, A.; Lopez-Martens, R.; Boutu, W.

2005-01-01

Full text: In the past decade, the dynamics of atomic and small molecular systems in strong laser fields has received enormous attention, but was mainly studied with femtosecond laser fields. We report on first applications of attosecond extreme ultraviolet (XUV) pulse trains (APTs) from high-order harmonic generation (HHG) for the study of atomic and molecular electron and ion dynamics in strong laser fields utilizing the Velocity Map Imaging Technique. The APTs were generated in argon from harmonics 13 to 35 of a 35 fs Ti:sapphire laser, and spatially and temporally overlapped with an intense IR laser field (up to 5x10 13 W/cm 2 ) in the interaction region of a Velocity Map Imaging (VMI) machine. In the VMI setup, electrons and ions that were created at the crossing point of the laser fields and an atomic or molecular beam were accelerated in a dc-electric field towards a two-dimensional position-sensitive detector, allowing to reconstruct the full initial three-dimensional velocity distribution. The poster will focus on results that were obtained for argon atoms. We recorded the velocity distribution of electron wave packets that were strongly driven in the IR laser field after their generation in Ar via single-photon ionization by attosecond XUV pulses. The 3D evolution of the electron wave packets was observed on an attosecond timescale. In addition to earlier experiments with APTs using a magnetic bottle electron time-of-flight spectrometers and with single attosecond pulses, the angular dependence of the electrons kinetic energies can give further insight into the details of the dynamics. Initial results that were obtained for molecular systems like H 2 , D 2 , N 2 , and CO 2 using the same powerful approach will be highlighted as well. We will show, that detailed insight into the dynamics of these systems in strong laser fields can be obtained (e.g. on the alignment, above-threshold ionization, direct vs. sequential two-photon ionization, dissociation, and

LIDAR AND INS FUSION IN PERIODS OF GPS OUTAGES FOR MOBILE LASER SCANNING MAPPING SYSTEMS

Directory of Open Access Journals (Sweden)

I. Klein

2012-09-01

Full Text Available Mobile laser scanning systems are becoming an increasingly popular means to obtain 3D coverage on a large scale. To perform the mapping, the exact position of the vehicle must be known throughout the trajectory. Exact position is achieved via integration of Global Positioning Systems (GPS and Inertial Navigation Systems (INS. Yet, in urban environments, cases of complete or even partial GPS outages may occur leaving the navigation solution to rely only on the INS. The INS navigation solution degrades with time as the Inertial Measurement Unit (IMU measurements contains noise, which permeates into the navigation equations. Degradation of the position determination leads to loss of data in such segments. To circumvent such drift and its effects, we propose fusing INS with lidar data by using building edges. This detection of edges is then translated into position data, which is used as an aiding to the INS. It thereby enables the determination of the vehicle position with a satisfactory level accuracy, sufficient to perform the laser-scanning based mapping in those outage periods.

Evaluating watershed protection programs in New York City's Cannonsville Reservoir source watershed using SWAT-HS

Science.gov (United States)

Hoang, L.; Mukundan, R.; Moore, K. E.; Owens, E. M.; Steenhuis, T. S.

2017-12-01

New York City (NYC)'s reservoirs supply over one billion gallons of drinking water each day to over nine million consumers in NYC and upstate communities. The City has invested more than $1.5 billion in watershed protection programs to maintain a waiver from filtration for the Catskill and Delaware Systems. In the last 25 years, the NYC Department of Environmental Protection (NYCDEP) has implemented programs in cooperation with upstate communities that include nutrient management, crop rotations, improvement of barnyards and manure storage, implementing tertiary treatment for Phosphorus (P) in wastewater treatment plants, and replacing failed septic systems in an effort to reduce P loads to water supply reservoirs. There have been several modeling studies evaluating the effect of agricultural Best Management Practices (BMPs) on P control in the Cannonsville watershed in the Delaware System. Although these studies showed that BMPs would reduce dissolved P losses, they were limited to farm-scale or watershed-scale estimates of reduction factors without consideration of the dynamic nature of overland flow and P losses from variable source areas. Recently, we developed the process-based SWAT-Hillslope (SWAT-HS) model, a modified version of the Soil and Water Assessment Tool (SWAT) that can realistically predict variable source runoff processes. The objective of this study is to use the SWAT-HS model to evaluate watershed protection programs addressing both point and non-point sources of P. SWAT-HS predicts streamflow very well for the Cannonsville watershed with a daily Nash Sutcliffe Efficiency (NSE) of 0.85 at the watershed outlet and NSE values ranging from 0.56 - 0.82 at five other locations within the watershed. Based on good hydrological prediction, we applied the model to predict P loads using detailed P inputs that change over time due to the implementation of watershed protection programs. Results from P model predictions provide improved projections of P

OMI/Aura and MODIS/Aqua Merged Cloud Product 1-Orbit L2 Swath 13x24 km V003

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura and MODIS/Aqua Merged Cloud Product 1-Orbit L2 Swath 13x24 km (OMMYDCLD) is a Level-2 orbital product that combines cloud parameters retrieved by the...

Effects of cross-education on the muscle after a period of unilateral limb immobilization using a shoulder sling and swathe.

Science.gov (United States)

Magnus, Charlene R A; Barss, Trevor S; Lanovaz, Joel L; Farthing, Jonathan P

2010-12-01

The purpose of this study was to apply cross-education during 4 wk of unilateral limb immobilization using a shoulder sling and swathe to investigate the effects on muscle strength, muscle size, and muscle activation. Twenty-five right-handed participants were assigned to one of three groups as follows: the Immob + Train group wore a sling and swathe and strength trained (n = 8), the Immob group wore a sling and swathe and did not strength train (n = 8), and the Control group received no treatment (n = 9). Immobilization was applied to the nondominant (left) arm. Strength training consisted of maximal isometric elbow flexion and extension of the dominant (right) arm 3 days/wk. Torque (dynamometer), muscle thickness (ultrasound), maximal voluntary activation (interpolated twitch), and electromyography (EMG) were measured. The change in right biceps and triceps brachii muscle thickness [7.0 ± 1.9 and 7.1 ± 2.2% (SE), respectively] was greater for Immob + Train than Immob (0.4 ± 1.2 and -1.9 ± 1.7%) and Control (0.8 ± 0.5 and 0.0 ± 1.1%, P effect on maximal voluntary activation or EMG. The cross-education effect on the immobilized limb was greater after elbow extension training. This study suggests that strength training the nonimmobilized limb benefits the immobilized limb for muscle size and strength.

Automatic camera to laser calibration for high accuracy mobile mapping systems using INS

Science.gov (United States)

Goeman, Werner; Douterloigne, Koen; Gautama, Sidharta

2013-09-01

A mobile mapping system (MMS) is a mobile multi-sensor platform developed by the geoinformation community to support the acquisition of huge amounts of geodata in the form of georeferenced high resolution images and dense laser clouds. Since data fusion and data integration techniques are increasingly able to combine the complementary strengths of different sensor types, the external calibration of a camera to a laser scanner is a common pre-requisite on today's mobile platforms. The methods of calibration, nevertheless, are often relatively poorly documented, are almost always time-consuming, demand expert knowledge and often require a carefully constructed calibration environment. A new methodology is studied and explored to provide a high quality external calibration for a pinhole camera to a laser scanner which is automatic, easy to perform, robust and foolproof. The method presented here, uses a portable, standard ranging pole which needs to be positioned on a known ground control point. For calibration, a well studied absolute orientation problem needs to be solved. In many cases, the camera and laser sensor are calibrated in relation to the INS system. Therefore, the transformation from camera to laser contains the cumulated error of each sensor in relation to the INS. Here, the calibration of the camera is performed in relation to the laser frame using the time synchronization between the sensors for data association. In this study, the use of the inertial relative movement will be explored to collect more useful calibration data. This results in a better intersensor calibration allowing better coloring of the clouds and a more accurate depth mask for images, especially on the edges of objects in the scene.

In-Field, In Situ, and In Vivo 3-Dimensional Elemental Mapping for Plant Tissue and Soil Analysis Using Laser-Induced Breakdown Spectroscopy

Directory of Open Access Journals (Sweden)

Chunjiang Zhao

2016-10-01

Full Text Available Sensing and mapping element distributions in plant tissues and its growth environment has great significance for understanding the uptake, transport, and accumulation of nutrients and harmful elements in plants, as well as for understanding interactions between plants and the environment. In this study, we developed a 3-dimensional elemental mapping system based on laser-induced breakdown spectroscopy that can be deployed in- field to directly measure the distribution of multiple elements in living plants as well as in the soil. Mapping is performed by a fast scanning laser, which ablates a micro volume of a sample to form a plasma. The presence and concentration of specific elements are calculated using the atomic, ionic, and molecular spectral characteristics of the plasma emission spectra. Furthermore, we mapped the pesticide residues in maize leaves after spraying to demonstrate the capacity of this method for trace elemental mapping. We also used the system to quantitatively detect the element concentrations in soil, which can be used to further understand the element transport between plants and soil. We demonstrate that this method has great potential for elemental mapping in plant tissues and soil with the advantages of 3-dimensional and multi-elemental mapping, in situ and in vivo measurement, flexible use, and low cost.

Performance analysis of a compact and low-cost mapping-grade mobile laser scanning system

Science.gov (United States)

Julge, Kalev; Vajakas, Toivo; Ellmann, Artu

2017-10-01

The performance of a low-cost, self-contained, compact, and easy to deploy mapping-grade mobile laser scanning (MLS) system, which is composed of a light detection and ranging sensor Velodyne VLP-16 and a dual antenna global navigation satellite system/inertial navigation system SBG Systems Ellipse-D, is analyzed. The field tests were carried out in car-mounted and backpack modes for surveying road engineering structures (such as roads, parking lots, underpasses, and tunnels) and coastal erosion zones, respectively. The impact of applied calculation principles on trajectory postprocessing, direct georeferencing, and the theoretical accuracy of the system is analyzed. A calibration method, based on Bound Optimization BY Quadratic Approximation, for finding the boresight angles of an MLS system is proposed. The resulting MLS point clouds are compared with high-accuracy static terrestrial laser scanning data and survey-grade MLS data from a commercially manufactured MLS system. The vertical, horizontal, and relative accuracy are assessed-the root-mean-square error (RMSE) values were determined to be 8, 15, and 3 cm, respectively. Thus, the achieved mapping-grade accuracy demonstrates that this relatively compact and inexpensive self-assembled MLS can be successfully used for surveying the geometry and deformations of terrain, buildings, road, and other engineering structures.

Object-based analysis of multispectral airborne laser scanner data for land cover classification and map updating

Science.gov (United States)

Matikainen, Leena; Karila, Kirsi; Hyyppä, Juha; Litkey, Paula; Puttonen, Eetu; Ahokas, Eero

2017-06-01

During the last 20 years, airborne laser scanning (ALS), often combined with passive multispectral information from aerial images, has shown its high feasibility for automated mapping processes. The main benefits have been achieved in the mapping of elevated objects such as buildings and trees. Recently, the first multispectral airborne laser scanners have been launched, and active multispectral information is for the first time available for 3D ALS point clouds from a single sensor. This article discusses the potential of this new technology in map updating, especially in automated object-based land cover classification and change detection in a suburban area. For our study, Optech Titan multispectral ALS data over a suburban area in Finland were acquired. Results from an object-based random forests analysis suggest that the multispectral ALS data are very useful for land cover classification, considering both elevated classes and ground-level classes. The overall accuracy of the land cover classification results with six classes was 96% compared with validation points. The classes under study included building, tree, asphalt, gravel, rocky area and low vegetation. Compared to classification of single-channel data, the main improvements were achieved for ground-level classes. According to feature importance analyses, multispectral intensity features based on several channels were more useful than those based on one channel. Automatic change detection for buildings and roads was also demonstrated by utilising the new multispectral ALS data in combination with old map vectors. In change detection of buildings, an old digital surface model (DSM) based on single-channel ALS data was also used. Overall, our analyses suggest that the new data have high potential for further increasing the automation level in mapping. Unlike passive aerial imaging commonly used in mapping, the multispectral ALS technology is independent of external illumination conditions, and there are

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.

GeoMapApp as a platform for visualizing marine data from Polar Regions

Science.gov (United States)

Nitsche, F. O.; Ryan, W. B.; Carbotte, S. M.; Ferrini, V.; Goodwillie, A. M.; O'hara, S. H.; Weissel, R.; McLain, K.; Chinhong, C.; Arko, R. A.; Chan, S.; Morton, J. J.; Pomeroy, D.

2012-12-01

To maximize the investment in expensive fieldwork the resulting data should be re-used as much as possible. In addition, unnecessary duplication of data collection effort should be avoided. This becomes even more important if access to field areas is as difficult and expensive as it is in Polar Regions. Making existing data discoverable in an easy to use platform is key to improve re-use and avoid duplication. A common obstacle is that use of existing data is often limited to specialists who know of the data existence and also have the right tools to view and analyze these data. GeoMapApp is a free, interactive, map based tool that allows users to discover, visualize, and analyze a large number of data sets. In addition to a global view, it provides polar map projections for displaying data in Arctic and Antarctic areas. Data that have currently been added to the system include Arctic swath bathymetry data collected from the USCG icebreaker Healy. These data are collected almost continuously including from cruises where bathymetry is not the main objective and for which existence of the acquired data may not be well known. In contrast, existence of seismic data from the Antarctic continental margin is well known in the seismic community. They are archived at and can be accessed through the Antarctic Seismic Data Library System (SDLS). Incorporating these data into GeoMapApp makes an even broader community aware of these data and the custom interface, which includes capabilities to visualize and explore these data, allows users without specific software or knowledge of the underlying data format to access the data. In addition to investigating these datasets, GeoMapApp provides links to the actual data sources to allow specialists the opportunity to re-use the original data. Important identification of data sources and data references are achieved on different levels. For access to the actual Antarctic seismic data GeoMapApp links to the SDLS site, where users have

Mapping the Antarctic grounding line with CryoSat-2 radar altimetry

Science.gov (United States)

Bamber, J. L.; Dawson, G. J.

2017-12-01

The grounding line, where grounded ice begins to float, is the boundary at which the ocean has the greatest influence on the ice-sheet. Its position and dynamics are critical in assessing the stability of the ice-sheet, for mass budget calculations and as an input into numerical models. The most reliable approaches to map the grounding line remotely are to measure the limit of tidal flexure of the ice shelf using differential synthetic aperture radar interferometry (DInSAR) or ICESat repeat-track measurements. However, these methods are yet to provide satisfactory spatial and temporal coverage of the whole of the Antarctic grounding zone. It has not been possible to use conventional radar altimetry to map the limit of tidal flexure of the ice shelf because it performs poorly near breaks in slope, commonly associated with the grounding zone. The synthetic aperture radar interferometric (SARin) mode of CryoSat-2, performs better over steeper margins of the ice sheet and allows us to achieve this. The SARin mode combines "delay Doppler" processing with a cross-track interferometer, and enables us to use elevations based on the first return (point of closest approach or POCA) and "swath processed" elevations derived from the time-delayed waveform beyond the first return, to significantly improve coverage. Here, we present a new method to map the limit of tidal motion from a combination of POCA and swath data. We test this new method on the Siple Coast region of the Ross Ice Shelf, and the mapped grounding line is in good agreement with previous observations from DinSAR and ICESat measurements. There is, however, an approximately constant seaward offset between these methods and ours, which we believe is due to the poorer precision of CryoSat-2. This new method has improved the coverage of the grounding zone across the Siple Coast, and can be applied to the rest of Antarctica.

Mapping of electromagnetic fields enhanced by gold nanostructures

DEFF Research Database (Denmark)

Fiutowski, Jacek; Maibohm, Christian; Kostiučenko, Oksana

2012-01-01

Laser ablation of an ‘imaging’ polymer layer allows near-field mapping of metal nanostructures with subdiffraction resolution......Laser ablation of an ‘imaging’ polymer layer allows near-field mapping of metal nanostructures with subdiffraction resolution...

Laser-beam-induced current mapping evaluation of porous silicon-based passivation in polycrystalline silicon solar cells

Energy Technology Data Exchange (ETDEWEB)

Rabha, M. Ben; Bessais, B. [Laboratoire de Nanomateriaux et des Systemes pour l' Energie, Centre de Recherches et des Technologies de l' Energie - Technopole de Borj-Cedria BP 95, 2050 Hammam-Lif (Tunisia); Dimassi, W.; Bouaicha, M.; Ezzaouia, H. [Laboratoire de photovoltaique, des semiconducteurs et des nanostructures, Centre de Recherches et des Technologies de l' Energie - Technopole de Borj-Cedria BP 95, 2050 Hammam-Lif (Tunisia)

2009-05-15

In the present work, we report on the effect of introducing a superficial porous silicon (PS) layer on the performance of polycrystalline silicon (pc-Si) solar cells. Laser-beam-induced current (LBIC) mapping shows that the PS treatment on the emitter of pc-Si solar cells improves their quantum response and reduce the grain boundaries (GBs) activity. After the porous silicon treatment, mapping investigation shows an enhancement of the LBIC and the internal quantum efficiency (IQE), due to an improvement of the minority carrier diffusion length and the passivation of recombination centers at the GBs as compared to the reference substrate. It was quantitatively shown that porous silicon treatment can passivate both the grains and GBs. (author)

Multitemporal ALSM change detection, sediment delivery, and process mapping at an active earthflow

Science.gov (United States)

DeLong, Stephen B.; Prentice, Carol S.; Hilley, George E.; Ebert, Yael

2012-01-01

Remote mapping and measurement of surface processes at high spatial resolution is among the frontiers in Earth surface process research. Remote measurements that allow meter-scale mapping of landforms and quantification of landscape change can revolutionize the study of landscape evolution on human timescales. At Mill Gulch in northern California, USA, an active earthflow was surveyed in 2003 and 2007 by airborne laser swath mapping (ALSM), enabling meter-scale quantification of landscape change. We calculate four-year volumetric flux from the earthflow and compare it to long-term catchment average erosion rates from cosmogenic radionuclide inventories from adjacent watersheds. We also present detailed maps of changing features on the earthflow, from which we can derive velocity estimates and infer dominant process. These measurements rely on proper digital elevation model (DEM) generation and a simple surface-matching technique to align the multitemporal data in a manner that eliminates systematic error in either dataset. The mean surface elevation of the earthflow and an opposite slope that was directly influenced by the earthflow decreased 14 ± 1 mm/yr from 2003 to 2007. By making the conservative assumption that these features were the dominant contributor of sediment flux from the entire Mill Gulch drainage basin during this time interval, we calculate a minimum catchment-averaged erosion rate of 0·30 ± 0·02 mm/yr. Analysis of beryllium-10 (10Be) concentrations in fluvial sand from nearby Russian Gulch and the South Fork Gualala River provide catchment averaged erosion rates of 0·21 ± 0·04 and 0·23 ± 0·03 mm/yr respectively. From translated landscape features, we can infer surface velocities ranging from 0·5 m/yr in the wide upper ‘source’ portion of the flow to 5 m/yr in the narrow middle ‘transport’ portion of the flow. This study re-affirms the importance of mass wasting processes in the sediment budgets of

Development of Kinematic 3D Laser Scanning System for Indoor Mapping and As-Built BIM Using Constrained SLAM

Directory of Open Access Journals (Sweden)

Jaehoon Jung

2015-10-01

Full Text Available The growing interest and use of indoor mapping is driving a demand for improved data-acquisition facility, efficiency and productivity in the era of the Building Information Model (BIM. The conventional static laser scanning method suffers from some limitations on its operability in complex indoor environments, due to the presence of occlusions. Full scanning of indoor spaces without loss of information requires that surveyors change the scanner position many times, which incurs extra work for registration of each scanned point cloud. Alternatively, a kinematic 3D laser scanning system, proposed herein, uses line-feature-based Simultaneous Localization and Mapping (SLAM technique for continuous mapping. Moreover, to reduce the uncertainty of line-feature extraction, we incorporated constrained adjustment based on an assumption made with respect to typical indoor environments: that the main structures are formed of parallel or orthogonal line features. The superiority of the proposed constrained adjustment is its reduction for uncertainties of the adjusted lines, leading to successful data association process. In the present study, kinematic scanning with and without constrained adjustment were comparatively evaluated in two test sites, and the results confirmed the effectiveness of the proposed system. The accuracy of the 3D mapping result was additionally evaluated by comparison with the reference points acquired by a total station: the Euclidean average distance error was 0.034 m for the seminar room and 0.043 m for the corridor, which satisfied the error tolerance for point cloud acquisition (0.051 m according to the guidelines of the General Services Administration for BIM accuracy.

Mapping Nearby Terrain in 3D by Use of a Grid of Laser Spots

Science.gov (United States)

Padgett, Curtis; Liebe, Carl; Chang, Johnny; Brown, Kenneth

2007-01-01

A proposed optoelectronic system, to be mounted aboard an exploratory robotic vehicle, would be used to generate a three-dimensional (3D) map of nearby terrain and obstacles for purposes of navigating the vehicle across the terrain and avoiding the obstacles. The difference between this system and the other systems would lie in the details of implementation. In this system, the illumination would be provided by a laser. The beam from the laser would pass through a two-dimensional diffraction grating, which would divide the beam into multiple beams propagating in different, fixed, known directions. These beams would form a grid of bright spots on the nearby terrain and obstacles. The centroid of each bright spot in the image would be computed. For each such spot, the combination of (1) the centroid, (2) the known direction of the light beam that produced the spot, and (3) the known baseline would constitute sufficient information for calculating the 3D position of the spot.

The beauty of being (label)-free: sample preparation methods for SWATH-MS and next-generation targeted proteomics

Science.gov (United States)

Campbell, Kate; Deery, Michael J.; Lilley, Kathryn S.; Ralser, Markus

2014-01-01

The combination of qualitative analysis with label-free quantification has greatly facilitated the throughput and flexibility of novel proteomic techniques. However, such methods rely heavily on robust and reproducible sample preparation procedures. Here, we benchmark a selection of in gel, on filter, and in solution digestion workflows for their application in label-free proteomics. Each procedure was associated with differing advantages and disadvantages. The in gel methods interrogated were cost effective, but were limited in throughput and digest efficiency. Filter-aided sample preparations facilitated reasonable processing times and yielded a balanced representation of membrane proteins, but led to a high signal variation in quantification experiments. Two in solution digest protocols, however, gave optimal performance for label-free proteomics. A protocol based on the detergent RapiGest led to the highest number of detected proteins at second-best signal stability, while a protocol based on acetonitrile-digestion, RapidACN, scored best in throughput and signal stability but came second in protein identification. In addition, we compared label-free data dependent (DDA) and data independent (SWATH) acquisition on a TripleTOF 5600 instrument. While largely similar in protein detection, SWATH outperformed DDA in quantification, reducing signal variation and markedly increasing the number of precisely quantified peptides. PMID:24741437

Characterization of hard coatings produced by laser cladding using laser-induced breakdown spectroscopy technique

Energy Technology Data Exchange (ETDEWEB)

Varela, J.A.; Amado, J.M.; Tobar, M.J.; Mateo, M.P.; Yañez, A.; Nicolas, G., E-mail: gines@udc.es

2015-05-01

Highlights: • Chemical mapping and profiling by laser-induced breakdown spectroscopy (LIBS) of coatings produced by laser cladding. • Production of laser clads using tungsten carbide (WC) and nickel based matrix (NiCrBSi) powders. • Calibration by LIBS of hardfacing alloys with different WC concentrations. - Abstract: Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. In this work, laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder have been produced on stainless steel substrates of austenitic type (AISI 304) in a first step and then chemically characterized by laser-induced breakdown spectroscopy (LIBS) technique. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks and on large areas with overlapped tracks. The results achieved by LIBS technique and applied for the first time to the analysis of laser clads provided the chemical composition of the tungsten carbides in metal alloy matrix. Different measurement modes (multiple point analyses, depth profiles and chemical maps) have been employed, demonstrating the usefulness of LIBS technique for the characterization of laser clads based on hardfacing alloys. The behavior of hardness can be explained by LIBS maps which evidenced the partial dilution of some WC spheres in the coating.

A novel gridding algorithm to create regional trace gas maps from satellite observations

Science.gov (United States)

Kuhlmann, G.; Hartl, A.; Cheung, H. M.; Lam, Y. F.; Wenig, M. O.

2014-02-01

The recent increase in spatial resolution for satellite instruments has made it feasible to study distributions of trace gas column densities on a regional scale. For this application a new gridding algorithm was developed to map measurements from the instrument's frame of reference (level 2) onto a longitude-latitude grid (level 3). The algorithm is designed for the Ozone Monitoring Instrument (OMI) and can easily be employed for similar instruments - for example, the upcoming TROPOspheric Monitoring Instrument (TROPOMI). Trace gas distributions are reconstructed by a continuous parabolic spline surface. The algorithm explicitly considers the spatially varying sensitivity of the sensor resulting from the instrument function. At the swath edge, the inverse problem of computing the spline coefficients is very sensitive to measurement errors and is regularised by a second-order difference matrix. Since this regularisation corresponds to the penalty term for smoothing splines, it similarly attenuates the effect of measurement noise over the entire swath width. Monte Carlo simulations are conducted to study the performance of the algorithm for different distributions of trace gas column densities. The optimal weight of the penalty term is found to be proportional to the measurement uncertainty and the width of the instrument function. A comparison with an established gridding algorithm shows improved performance for small to moderate measurement errors due to better parametrisation of the distribution. The resulting maps are smoother and extreme values are more accurately reconstructed. The performance improvement is further illustrated with high-resolution distributions obtained from a regional chemistry model. The new algorithm is applied to tropospheric NO2 column densities measured by OMI. Examples of regional NO2 maps are shown for densely populated areas in China, Europe and the United States of America. This work demonstrates that the newly developed gridding

A novel gridding algorithm to create regional trace gas maps from satellite observations

Directory of Open Access Journals (Sweden)

G. Kuhlmann

2014-02-01

Full Text Available The recent increase in spatial resolution for satellite instruments has made it feasible to study distributions of trace gas column densities on a regional scale. For this application a new gridding algorithm was developed to map measurements from the instrument's frame of reference (level 2 onto a longitude–latitude grid (level 3. The algorithm is designed for the Ozone Monitoring Instrument (OMI and can easily be employed for similar instruments – for example, the upcoming TROPOspheric Monitoring Instrument (TROPOMI. Trace gas distributions are reconstructed by a continuous parabolic spline surface. The algorithm explicitly considers the spatially varying sensitivity of the sensor resulting from the instrument function. At the swath edge, the inverse problem of computing the spline coefficients is very sensitive to measurement errors and is regularised by a second-order difference matrix. Since this regularisation corresponds to the penalty term for smoothing splines, it similarly attenuates the effect of measurement noise over the entire swath width. Monte Carlo simulations are conducted to study the performance of the algorithm for different distributions of trace gas column densities. The optimal weight of the penalty term is found to be proportional to the measurement uncertainty and the width of the instrument function. A comparison with an established gridding algorithm shows improved performance for small to moderate measurement errors due to better parametrisation of the distribution. The resulting maps are smoother and extreme values are more accurately reconstructed. The performance improvement is further illustrated with high-resolution distributions obtained from a regional chemistry model. The new algorithm is applied to tropospheric NO2 column densities measured by OMI. Examples of regional NO2 maps are shown for densely populated areas in China, Europe and the United States of America. This work demonstrates that the newly

Kadının ve Kaderin “Tırpan”ı Swath Of Woman And Fate

Directory of Open Access Journals (Sweden)

Salim DURUKOĞLU

2013-07-01

Full Text Available The novel Tırpan (Swath would be the most prominent outcome of a historical and literary brainstorming about the World Women’s Day in particular and the unfortunate faith of women in general. The novel Tırpan, which first merges and then separates the concepts of woman and faith, is one or probably the only work with a thesis that comes to the mind first in that it was written with the naïve belief that the faith will show up not before but after it is lived and generally all people particularly the women can write their faith; it questions the faith or the unfortunate faith of people, especially the that of women within the boundaries of the genre of novel, expanding to cover class clashes, the breaths of Marxist ideologies, and feminist viewpoints. Inherited from an image of old tool in our mind, accompanied with the motive of Azrael claiming lives with the swath in its hands, swath gains a function beyond that of an agricultural tool in this novel. Swath changes hand from Azrael to women and the woman punishes the man who disrespects her field of existence and freedom, thus reclaims and rewrites her faith with her own hands using the swath. Swath would preserve its function as a goal and an instrument in the writer’s hand, however, in terms of its consequences it will transform into a symbol of woman’s revolution as the hammer and sickle of the Bolshevist revolution. The author, who wants to create a resisting, active and activist women spirit and mentality instead of an understanding which takes it as an escape to commit suicide by hanging themselves when they are forced to get married as a passive reaction, tries to impose the fatalist Turkish society and Turkish women with the idea that they can reclaim their faiths and direct their own lives, offering and inspiring a shift of awareness through this novel. Özelde Dünya Kadınlar Günü ve genelde kadının makus talihi ve tarihi ekseninde ve edebiyat düzleminde yapaca

Wide area methane emissions mapping with airborne IPDA lidar

Science.gov (United States)

Bartholomew, Jarett; Lyman, Philip; Weimer, Carl; Tandy, William

2017-08-01

Methane emissions from natural gas production, storage, and transportation are potential sources of greenhouse gas emissions. Methane leaks also constitute revenue loss potential from operations. Since 2013, Ball Aerospace has been developing advanced airborne sensors using integrated path differential absorption (IPDA) LIDAR instrumentation to identify methane, propane, and longer-chain alkanes in the lowest region of the atmosphere. Additional funding has come from the U.S. Department of Transportation, Pipeline and Hazardous Materials Administration (PHMSA) to upgrade instrumentation to a broader swath coverage of up to 400 meters while maintaining high spatial sampling resolution and geolocation accuracy. Wide area coverage allows efficient mapping of emissions from gathering and distribution networks, processing facilities, landfills, natural seeps, and other distributed methane sources. This paper summarizes the benefits of advanced instrumentation for aerial methane emission mapping, describes the operating characteristics and design of this upgraded IPDA instrumentation, and reviews technical challenges encountered during development and deployment.

Test of the Capability of Laser Line Scan Technology to Support Benthic Habitat Mapping in Coral Reef Ecosystems, Maui Island, November 2006

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The utility of Laser Line Scan (LLS) Technology for optical validation of benthic habitat map data from coral reef ecosystems was tested with a deployment of a...

OMI/Aura and MODIS/Aqua Merged Cloud Product 1-Orbit L2 Swath 13x24 km V003 (OMMYDCLD) at GES DISC

Data.gov (United States)

National Aeronautics and Space Administration — The OMI/Aura and MODIS/Aqua Merged Cloud Product 1-Orbit L2 Swath 13x24 km (OMMYDCLD) is a Level-2 orbital product that combines cloud parameters retrieved by the...

High-resolution low-frequency fluctuation map of a multimode laser diode subject to filtered optical feedback via a fiber Bragg grating.

Science.gov (United States)

Baladi, Fadwa; Lee, Min Won; Burie, Jean-René; Bettiati, Mauro A; Boudrioua, Azzedine; Fischer, Alexis P A

2016-07-01

A highly detailed and extended map of low-frequency fluctuations is established for a high-power multi-mode 980 nm laser diode subject to filtered optical feedback from a fiber Bragg grating. The low-frequency fluctuations limits and substructures exhibit substantial differences with previous works.

Improvements to the swath-level near-surface atmospheric state parameter retrievals within the NRL Ocean Surface Flux System (NFLUX)

Science.gov (United States)

May, J. C.; Rowley, C. D.; Meyer, H.

2017-12-01

The Naval Research Laboratory (NRL) Ocean Surface Flux System (NFLUX) is an end-to-end data processing and assimilation system used to provide near-real-time satellite-based surface heat flux fields over the global ocean. The first component of NFLUX produces near-real-time swath-level estimates of surface state parameters and downwelling radiative fluxes. The focus here will be on the satellite swath-level state parameter retrievals, namely surface air temperature, surface specific humidity, and surface scalar wind speed over the ocean. Swath-level state parameter retrievals are produced from satellite sensor data records (SDRs) from four passive microwave sensors onboard 10 platforms: the Special Sensor Microwave Imager/Sounder (SSMIS) sensor onboard the DMSP F16, F17, and F18 platforms; the Advanced Microwave Sounding Unit-A (AMSU-A) sensor onboard the NOAA-15, NOAA-18, NOAA-19, Metop-A, and Metop-B platforms; the Advanced Technology Microwave Sounder (ATMS) sensor onboard the S-NPP platform; and the Advanced Microwave Scannin Radiometer 2 (AMSR2) sensor onboard the GCOM-W1 platform. The satellite SDRs are translated into state parameter estimates using multiple polynomial regression algorithms. The coefficients to the algorithms are obtained using a bootstrapping technique with all available brightness temperature channels for a given sensor, in addition to a SST field. For each retrieved parameter for each sensor-platform combination, unique algorithms are developed for ascending and descending orbits, as well as clear vs cloudy conditions. Each of the sensors produces surface air temperature and surface specific humidity retrievals. The SSMIS and AMSR2 sensors also produce surface scalar wind speed retrievals. Improvement is seen in the SSMIS retrievals when separate algorithms are used for the even and odd scans, with the odd scans performing better than the even scans. Currently, NFLUX treats all SSMIS scans as even scans. Additional improvement in all of

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

Directory of Open Access Journals (Sweden)

Taekjun Oh

2015-07-01

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

Mapping Forest Species Composition Using Imaging Spectrometry and Airborne Laser Scanner Data

Science.gov (United States)

Torabzadeh, H.; Morsdorf, F.; Leiterer, R.; Schaepman, M. E.

2013-09-01

Accurate mapping of forest species composition is an important aspect of monitoring and management planning related to ecosystem functions and services associated with water refinement, carbon sequestration, biodiversity, and wildlife habitats. Although different vegetation species often have unique spectral signatures, mapping based on spectral reflectance properties alone is often an ill-posed problem, since the spectral signature is as well influenced by age, canopy gaps, shadows and background characteristics. Thus, reducing the unknown variation by knowing the structural parameters of different species should improve determination procedures. In this study we combine imaging spectrometry (IS) and airborne laser scanning (ALS) data of a mixed needle and broadleaf forest to differentiate tree species more accurately as single-instrument data could do. Since forest inventory data in dense forests involve uncertainties, we tried to refine them by using individual tree crowns (ITC) position and shape, which derived from ALS data. Comparison of the extracted spectra from original field data and the modified one shows how ALS-derived shape and position of ITCs can improve separablity of the different species. The spatially explicit information layers containing both the spectral and structural components from the IS and ALS datasets were then combined by using a non-parametric support vector machine (SVM) classifier.

Automatic Mapping of Forest Stands Based on Three-Dimensional Point Clouds Derived from Terrestrial Laser-Scanning

Directory of Open Access Journals (Sweden)

Tim Ritter

2017-07-01

Full Text Available Mapping of exact tree positions can be regarded as a crucial task of field work associated with forest monitoring, especially on intensive research plots. We propose a two-stage density clustering approach for the automatic mapping of tree positions, and an algorithm for automatic tree diameter estimates based on terrestrial laser-scanning (TLS point cloud data sampled under limited sighting conditions. We show that our novel approach is able to detect tree positions in a mixed and vertically structured stand with an overall accuracy of 91.6%, and with omission- and commission error of only 5.7% and 2.7% respectively. Moreover, we were able to reproduce the stand’s diameter in breast height (DBH distribution, and to estimate single trees DBH with a mean average deviation of ±2.90 cm compared with tape measurements as reference.

A framework to quantify uncertainties of seafloor backscatter from swath mapping echosounders

Science.gov (United States)

Malik, Mashkoor; Lurton, Xavier; Mayer, Larry

2018-06-01

Multibeam echosounders (MBES) have become a widely used acoustic remote sensing tool to map and study the seafloor, providing co-located bathymetry and seafloor backscatter. Although the uncertainty associated with MBES-derived bathymetric data has been studied extensively, the question of backscatter uncertainty has been addressed only minimally and hinders the quantitative use of MBES seafloor backscatter. This paper explores approaches to identifying uncertainty sources associated with MBES-derived backscatter measurements. The major sources of uncertainty are catalogued and the magnitudes of their relative contributions to the backscatter uncertainty budget are evaluated. These major uncertainty sources include seafloor insonified area (1-3 dB), absorption coefficient (up to > 6 dB), random fluctuations in echo level (5.5 dB for a Rayleigh distribution), and sonar calibration (device dependent). The magnitudes of these uncertainty sources vary based on how these effects are compensated for during data acquisition and processing. Various cases (no compensation, partial compensation and full compensation) for seafloor insonified area, transmission losses and random fluctuations were modeled to estimate their uncertainties in different scenarios. Uncertainty related to the seafloor insonified area can be reduced significantly by accounting for seafloor slope during backscatter processing while transmission losses can be constrained by collecting full water column absorption coefficient profiles (temperature and salinity profiles). To reduce random fluctuations to below 1 dB, at least 20 samples are recommended to be used while computing mean values. The estimation of uncertainty in backscatter measurements is constrained by the fact that not all instrumental components are characterized and documented sufficiently for commercially available MBES. Further involvement from manufacturers in providing this essential information is critically required.

SWATHtoMRM: Development of High-Coverage Targeted Metabolomics Method Using SWATH Technology for Biomarker Discovery.

Science.gov (United States)

Zha, Haihong; Cai, Yuping; Yin, Yandong; Wang, Zhuozhong; Li, Kang; Zhu, Zheng-Jiang

2018-03-20

The complexity of metabolome presents a great analytical challenge for quantitative metabolite profiling, and restricts the application of metabolomics in biomarker discovery. Targeted metabolomics using multiple-reaction monitoring (MRM) technique has excellent capability for quantitative analysis, but suffers from the limited metabolite coverage. To address this challenge, we developed a new strategy, namely, SWATHtoMRM, which utilizes the broad coverage of SWATH-MS technology to develop high-coverage targeted metabolomics method. Specifically, SWATH-MS technique was first utilized to untargeted profile one pooled biological sample and to acquire the MS 2 spectra for all metabolites. Then, SWATHtoMRM was used to extract the large-scale MRM transitions for targeted analysis with coverage as high as 1000-2000 metabolites. Then, we demonstrated the advantages of SWATHtoMRM method in quantitative analysis such as coverage, reproducibility, sensitivity, and dynamic range. Finally, we applied our SWATHtoMRM approach to discover potential metabolite biomarkers for colorectal cancer (CRC) diagnosis. A high-coverage targeted metabolomics method with 1303 metabolites in one injection was developed to profile colorectal cancer tissues from CRC patients. A total of 20 potential metabolite biomarkers were discovered and validated for CRC diagnosis. In plasma samples from CRC patients, 17 out of 20 potential biomarkers were further validated to be associated with tumor resection, which may have a great potential in assessing the prognosis of CRC patients after tumor resection. Together, the SWATHtoMRM strategy provides a new way to develop high-coverage targeted metabolomics method, and facilitates the application of targeted metabolomics in disease biomarker discovery. The SWATHtoMRM program is freely available on the Internet ( http://www.zhulab.cn/software.php ).

Comparison of brass alloys composition by laser-induced breakdown spectroscopy and self-organizing maps

Energy Technology Data Exchange (ETDEWEB)

Pagnotta, Stefano; Grifoni, Emanuela; Legnaioli, Stefano [Applied and Laser Spectroscopy Laboratory, ICCOM-CNR, Research Area of Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); Lezzerini, Marco [Department of Earth Sciences, University of Pisa, Via S. Maria 53, 56126 Pisa (Italy); Lorenzetti, Giulia [Applied and Laser Spectroscopy Laboratory, ICCOM-CNR, Research Area of Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); Palleschi, Vincenzo, E-mail: vincenzo.palleschi@cnr.it [Applied and Laser Spectroscopy Laboratory, ICCOM-CNR, Research Area of Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); Department of Civilizations and Forms of Knowledge, University of Pisa, Via L. Galvani 1, 56126 Pisa (Italy)

2015-01-01

In this paper we face the problem of assessing similarities in the composition of different metallic alloys, using the laser-induced breakdown spectroscopy technique. The possibility of determining the degree of similarity through the use of artificial neural networks and self-organizing maps is discussed. As an example, we present a case study involving the comparison of two historical brass samples, very similar in their composition. The results of the paper can be extended to many other situations, not necessarily associated with cultural heritage and archeological studies, where objects with similar composition have to be compared. - Highlights: • A method for assessing the similarity of materials analyzed by LIBS is proposed. • Two very similar fragments of historical brass were analyzed. • Using a simple artificial neural network the composition of the two alloys was determined. • The composition of the two brass alloys was the same within the experimental error. • Using self-organizing maps, the probability of the alloys to have the same composition was assessed.

Comparison of brass alloys composition by laser-induced breakdown spectroscopy and self-organizing maps

International Nuclear Information System (INIS)

Pagnotta, Stefano; Grifoni, Emanuela; Legnaioli, Stefano; Lezzerini, Marco; Lorenzetti, Giulia; Palleschi, Vincenzo

2015-01-01

In this paper we face the problem of assessing similarities in the composition of different metallic alloys, using the laser-induced breakdown spectroscopy technique. The possibility of determining the degree of similarity through the use of artificial neural networks and self-organizing maps is discussed. As an example, we present a case study involving the comparison of two historical brass samples, very similar in their composition. The results of the paper can be extended to many other situations, not necessarily associated with cultural heritage and archeological studies, where objects with similar composition have to be compared. - Highlights: • A method for assessing the similarity of materials analyzed by LIBS is proposed. • Two very similar fragments of historical brass were analyzed. • Using a simple artificial neural network the composition of the two alloys was determined. • The composition of the two brass alloys was the same within the experimental error. • Using self-organizing maps, the probability of the alloys to have the same composition was assessed

Quantification of Lysine Acetylation and Succinylation Stoichiometry in Proteins Using Mass Spectrometric Data-Independent Acquisitions (SWATH)

Science.gov (United States)

Meyer, Jesse G.; D'Souza, Alexandria K.; Sorensen, Dylan J.; Rardin, Matthew J.; Wolfe, Alan J.; Gibson, Bradford W.; Schilling, Birgit

2016-11-01

Post-translational modification of lysine residues by NƐ-acylation is an important regulator of protein function. Many large-scale protein acylation studies have assessed relative changes of lysine acylation sites after antibody enrichment using mass spectrometry-based proteomics. Although relative acylation fold-changes are important, this does not reveal site occupancy, or stoichiometry, of individual modification sites, which is critical to understand functional consequences. Recently, methods for determining lysine acetylation stoichiometry have been proposed based on ratiometric analysis of endogenous levels to those introduced after quantitative per-acetylation of proteins using stable isotope-labeled acetic anhydride. However, in our hands, we find that these methods can overestimate acetylation stoichiometries because of signal interferences when endogenous levels of acylation are very low, which is especially problematic when using MS1 scans for quantification. In this study, we sought to improve the accuracy of determining acylation stoichiometry using data-independent acquisition (DIA). Specifically, we use SWATH acquisition to comprehensively collect both precursor and fragment ion intensity data. The use of fragment ions for stoichiometry quantification not only reduces interferences but also allows for determination of site-level stoichiometry from peptides with multiple lysine residues. We also demonstrate the novel extension of this method to measurements of succinylation stoichiometry using deuterium-labeled succinic anhydride. Proof of principle SWATH acquisition studies were first performed using bovine serum albumin for both acetylation and succinylation occupancy measurements, followed by the analysis of more complex samples of E. coli cell lysates. Although overall site occupancy was low (<1%), some proteins contained lysines with relatively high acetylation occupancy.

Wavelet analysis of polarization azimuths maps for laser images of myocardial tissue for the purpose of diagnosing acute coronary insufficiency

Science.gov (United States)

Wanchuliak, O. Ya.; Peresunko, A. P.; Bakko, Bouzan Adel; Kushnerick, L. Ya.

2011-09-01

This paper presents the foundations of a large scale - localized wavelet - polarization analysis - inhomogeneous laser images of histological sections of myocardial tissue. Opportunities were identified defining relations between the structures of wavelet coefficients and causes of death. The optical model of polycrystalline networks of myocardium protein fibrils is presented. The technique of determining the coordinate distribution of polarization azimuth of the points of laser images of myocardium histological sections is suggested. The results of investigating the interrelation between the values of statistical (statistical moments of the 1st-4th order) parameters are presented which characterize distributions of wavelet - coefficients polarization maps of myocardium layers and death reasons.

Evaluation of the optical design of laser Thomson scattering diagnostics for high-temperature EAST tokamak and low-temperature MAP-II divertor simulator

International Nuclear Information System (INIS)

Kado, Shinichiro; Scotti, Filippo; Xi Xiaoqi; Zhao Junyu

2009-01-01

The optical design of the laser Thomson scattering (LTS) system for EAST tokamak is now on-going. Based on the Visible YAG laser TVTS system developed in the MAP-II (material and plasma) steady-state linear divertor/edge plasma simulator at the University of Tokyo, the required specification and the applicability of the VIS-YAG-TVTS system was evaluated in terms of the photon number to be collected by the fiber light-guide to a spectrometer and the reciprocal linear dispersion of the spectrometer. Then, the possible design of the optical system was proposed. (author)

Improving maps of ice-sheet surface elevation change using combined laser altimeter and stereoscopic elevation model data

DEFF Research Database (Denmark)

Fredenslund Levinsen, Joanna; Howat, I. M.; Tscherning, C. C.

2013-01-01

We combine the complementary characteristics of laser altimeter data and stereoscopic digital elevation models (DEMs) to construct high-resolution (_100 m) maps of surface elevations and elevation changes over rapidly changing outlet glaciers in Greenland. Measurements from spaceborne and airborne...... laser altimeters have relatively low errors but are spatially limited to the ground tracks, while DEMs have larger errors but provide spatially continuous surfaces. The principle of our method is to fit the DEM surface to the altimeter point clouds in time and space to minimize the DEM errors and use...... that surface to extrapolate elevations away from altimeter flight lines. This reduces the DEM registration errors and fills the gap between the altimeter paths. We use data from ICESat and ATM as well as SPOT 5 DEMs from 2007 and 2008 and apply them to the outlet glaciers Jakobshavn Isbræ (JI...

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.

Visualizing fossilization using laser ablation-inductively coupled plasma-mass spectrometry maps of trace elements in Late Cretaceous bones

Science.gov (United States)

Koenig, A.E.; Rogers, R.R.; Trueman, C.N.

2009-01-01

Elemental maps generated by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) provide a previously unavailable high-resolution visualization of the complex physicochemical conditions operating within individual bones during the early stages of diagenesis and fossilization. A selection of LA-ICP-MS maps of bones collected from the Late Cretaceous of Montana (United States) and Madagascar graphically illustrate diverse paths to recrystallization, and reveal unique insights into geochemical aspects of taphonomic history. Some bones show distinct gradients in concentrations of rare earth elements and uranium, with highest concentrations at external bone margins. Others exhibit more intricate patterns of trace element uptake related to bone histology and its control on the flow paths of pore waters. Patterns of element uptake as revealed by LA-ICP-MS maps can be used to guide sampling strategies, and call into question previous studies that hinge upon localized bulk samples of fossilized bone tissue. LA-ICP-MS maps also allow for comparison of recrystallization rates among fossil bones, and afford a novel approach to identifying bones or regions of bones potentially suitable for extracting intact biogeochemical signals. ?? 2009 Geological Society of America.

Geologic Mapping of the Olympus Mons Volcano, Mars

Science.gov (United States)

Bleacher, J. E.; Williams, D. A.; Shean, D.; Greeley, R.

2012-01-01

We are in the third year of a three-year Mars Data Analysis Program project to map the morphology of the Olympus Mons volcano, Mars, using ArcGIS by ESRI. The final product of this project is to be a 1:1,000,000-scale geologic map. The scientific questions upon which this mapping project is based include understanding the volcanic development and modification by structural, aeolian, and possibly glacial processes. The project s scientific objectives are based upon preliminary mapping by Bleacher et al. [1] along a approx.80-km-wide north-south swath of the volcano corresponding to High Resolution Stereo Camera (HRSC) image h0037. The preliminary project, which covered approx.20% of the volcano s surface, resulted in several significant findings, including: 1) channel-fed lava flow surfaces are areally more abundant than tube-fed surfaces by a ratio of 5:1, 2) channel-fed flows consistently embay tube-fed flows, 3) lava fans appear to be linked to tube-fed flows, 4) no volcanic vents were identified within the map region, and 5) a Hummocky unit surrounds the summit and is likely a combination of non-channelized flows, dust, ash, and/or frozen volatiles. These results led to the suggestion that the volcano had experienced a transition from long-lived tube-forming eruptions to more sporadic and shorter-lived, channel-forming eruptions, as seen at Hawaiian volcanoes between the tholeiitic shield building phase (Kilauea to Mauna Loa) and alkalic capping phase (Hualalai and Mauna Kea).

Supporting autonomous vehicles by creating HD maps

Directory of Open Access Journals (Sweden)

Arpad Barsi

2017-10-01

Full Text Available Maps are constantly developing, also, the newly defined High Definition (HD maps increase the map content remarkably. They are based on three-dimensional survey, like laser scanning, and then stored in a fully new structured way to be able to support modern-day vehicles. Beyond the traditional lane based map content, they contain information about the roads’ neighbourhood. The goal of these maps is twofold. Primarily, they store the connections where the vehicles can travel with the description of the road-environment. Secondly, they efficiently support the exact vehicle positioning. The paper demonstrates the first results of a pilot study in the creation of HD map of an urban and a rural environment. The applied data collection technology was the terrestrial laser scanning, where the obtained point cloud was evaluated. The data storage has been solved by an in-house developed information storage model with the ability to help in vehicle control processes.

A hybrid structured-light measurement using a laser projector

Science.gov (United States)

Guo, Jiayu; Zhou, Xiang; Li, Dong; Wang, Chao; Fei, Zixuan; Li, Huanhuan

2017-06-01

The Fringe Projection System (FPS) and the Laser Stripe Projection System (LSPS) both have the limitations in 3D measurements. For a shiny and diffusive surface with complex shape, neither of the systems could manage it individually at a low cost. To overcome these difficulties, we propose a method combining these two ways of projections together using a laser projector, which could project fringe patterns and scanning-laser-stripes both. In this method, we obtain two disparity maps and two quality maps by FPS and LSPS, respectively. Then combine two disparity maps together by quality maps and reconstruct the surface of the object with the combined disparity map. Real experiments are carried out to verify the proposed method and to evaluate the system performance. The plain, the colored and the metal plastic mixed objects are all reconstructed successfully in the proposed method.

Near-field mapping by laser ablation of PMMA coatings

DEFF Research Database (Denmark)

Fiutowski, J.; Maibohm, C.; Kostiucenko, O.

2011-01-01

The optical near-field of lithography-defined gold nanostructures, arranged into regular arrays on a gold film, is characterized via ablation of a polymer coating by laser illumination. The method utilizes femto-second laser pulses from a laser scanning microscope which induces electrical field...... that the different stages in the ablation process can be controlled and characterized making the technique suitable for characterizing optical near-fields of metal nanostructures....

Acoustic mapping of shallow water gas releases using shipborne multibeam systems

Science.gov (United States)

Urban, Peter; Köser, Kevin; Weiß, Tim; Greinert, Jens

2015-04-01

Water column imaging (WCI) shipborne multibeam systems are effective tools for investigating marine free gas (bubble) release. Like single- and splitbeam systems they are very sensitive towards gas bubbles in the water column, and have the advantage of the wide swath opening angle, 120° or more allowing a better mapping and possible 3D investigations of targets in the water column. On the downside, WCI data are degraded by specific noise from side-lobe effects and are usually not calibrated for target backscattering strength analysis. Most approaches so far concentrated on manual investigations of bubbles in the water column data. Such investigations allow the detection of bubble streams (flares) and make it possible to get an impression about the strength of detected flares/the gas release. Because of the subjective character of these investigations it is difficult to understand how well an area has been investigated by a flare mapping survey and subjective impressions about flare strength can easily be fooled by the many acoustic effects multibeam systems create. Here we present a semi-automated approach that uses the behavior of bubble streams in varying water currents to detect and map their exact source positions. The focus of the method is application of objective rules for flare detection, which makes it possible to extract information about the quality of the seepage mapping survey, perform automated noise reduction and create acoustic maps with quality discriminators indicating how well an area has been mapped.

Multi-omic network-based interrogation of rat liver metabolism following gastric bypass surgery featuring SWATH proteomics.

Science.gov (United States)

Sridharan, Gautham Vivek; D'Alessandro, Matthew; Bale, Shyam Sundhar; Bhagat, Vicky; Gagnon, Hugo; Asara, John M; Uygun, Korkut; Yarmush, Martin L; Saeidi, Nima

2017-09-01

Morbidly obese patients often elect for Roux-en-Y gastric bypass (RYGB), a form of bariatric surgery that triggers a remarkable 30% reduction in excess body weight and reversal of insulin resistance for those who are type II diabetic. A more complete understanding of the underlying molecular mechanisms that drive the complex metabolic reprogramming post-RYGB could lead to innovative non-invasive therapeutics that mimic the beneficial effects of the surgery, namely weight loss, achievement of glycemic control, or reversal of non-alcoholic steatohepatitis (NASH). To facilitate these discoveries, we hereby demonstrate the first multi-omic interrogation of a rodent RYGB model to reveal tissue-specific pathway modules implicated in the control of body weight regulation and energy homeostasis. In this study, we focus on and evaluate liver metabolism three months following RYGB in rats using both SWATH proteomics, a burgeoning label free approach using high resolution mass spectrometry to quantify protein levels in biological samples, as well as MRM metabolomics. The SWATH analysis enabled the quantification of 1378 proteins in liver tissue extracts, of which we report the significant down-regulation of Thrsp and Acot13 in RYGB as putative targets of lipid metabolism for weight loss. Furthermore, we develop a computational graph-based metabolic network module detection algorithm for the discovery of non-canonical pathways, or sub-networks, enriched with significantly elevated or depleted metabolites and proteins in RYGB-treated rat livers. The analysis revealed a network connection between the depleted protein Baat and the depleted metabolite taurine, corroborating the clinical observation that taurine-conjugated bile acid levels are perturbed post-RYGB.

Characterization of hard coatings produced by laser cladding using laser-induced breakdown spectroscopy technique

Science.gov (United States)

Varela, J. A.; Amado, J. M.; Tobar, M. J.; Mateo, M. P.; Yañez, A.; Nicolas, G.

2015-05-01

Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. In this work, laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder have been produced on stainless steel substrates of austenitic type (AISI 304) in a first step and then chemically characterized by laser-induced breakdown spectroscopy (LIBS) technique. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks and on large areas with overlapped tracks. The results achieved by LIBS technique and applied for the first time to the analysis of laser clads provided the chemical composition of the tungsten carbides in metal alloy matrix. Different measurement modes (multiple point analyses, depth profiles and chemical maps) have been employed, demonstrating the usefulness of LIBS technique for the characterization of laser clads based on hardfacing alloys. The behavior of hardness can be explained by LIBS maps which evidenced the partial dilution of some WC spheres in the coating.

Laser-Assisted Field Evaporation and Three-Dimensional Atom-by-Atom Mapping of Diamond Isotopic Homojunctions.

Science.gov (United States)

Mukherjee, Samik; Watanabe, Hideyuki; Isheim, Dieter; Seidman, David N; Moutanabbir, Oussama

2016-02-10

It addition to its high evaporation field, diamond is also known for its limited photoabsorption, strong covalent bonding, and wide bandgap. These characteristics have been thought for long to also complicate the field evaporation of diamond and make its control hardly achievable on the atomistic-level. Herein, we demonstrate that the unique behavior of nanoscale diamond and its interaction with pulsed laser lead to a controlled field evaporation thus enabling three-dimensional atom-by-atom mapping of diamond (12)C/(13)C homojunctions. We also show that one key element in this process is to operate the pulsed laser at high energy without letting the dc bias increase out of bounds for diamond nanotip to withstand. Herein, the role of the dc bias in evaporation of diamond is essentially to generate free charge carriers within the nanotip via impact ionization. The mobile free charges screen the internal electric field, eventually creating a hole rich surface where the pulsed laser is effectively absorbed leading to an increase in the nanotip surface temperature. The effect of this temperature on the uncertainty in the time-of-flight of an ion, the diffusion of atoms on the surface of the nanotip, is also discussed. In addition to paving the way toward a precise manipulation of isotopes in diamond-based nanoscale and quantum structures, this result also elucidates some of the basic properties of dielectric nanostructures under high electric field.

METH-33 - Performance assessment for the high resolution and wide swath (HRWS) post-Sentinel-1 SAR system

DEFF Research Database (Denmark)

Zonno, Mariantonietta; Maria J., Sanjuan-Ferrer,; Lopez-Dekker, Paco

The next generation, post-Sentinel-1, ESA’s C-band synthetic aperture radar (SAR) system is conceived to provide simultaneously high azimuth resolution and wide swath width (HRWS).There are different ways in which the imaging capabilities of the HRWS SAR system can be exploited, which translate...... or numerical models and, if these are not available, real SAR images as well as numerical algorithms and some explicit simulations of the data and of the inversion process are employed. The tool uses as input the HRWS SAR instrument performance for the different applicable modes and produces as output results...

Impurity heterogeneity in natural pyrite and its relation to internal electric fields mapped using remote laser beam induced current

Energy Technology Data Exchange (ETDEWEB)

Laird, Jamie S., E-mail: csirojamie@gmail.com [CSIRO, Earth Science and Resource Engineering, Clayton, Victoria (Australia); Centre of Excellence in Ore Deposits (CODES), University of Tasmania, Hobart, Tasmania (Australia); School of Physics, University of Melbourne, Parkville 3010, Victoria (Australia); Large, Ross [Centre of Excellence in Ore Deposits (CODES), University of Tasmania, Hobart, Tasmania (Australia); Ryan, Chris G. [CSIRO, Earth Science and Resource Engineering, Clayton, Victoria (Australia); Centre of Excellence in Ore Deposits (CODES), University of Tasmania, Hobart, Tasmania (Australia); School of Physics, University of Melbourne, Parkville 3010, Victoria (Australia)

2013-07-01

Regions of band-bending in naturally occurring semiconducting sulfides are thought to drive electrochemical reactions with passing fluids. Metal bearing fluids within the right pH range interact with the electric fields at the surface resulting in precious metal ore genesis, even in under-saturated solutions. Metal reduction at the surface occurs via field assisted electron transfer from the semiconductor bulk to the ion in solution via surface states. Better understanding the role these regions and their texturing play on nucleating ore growth requires imaging of electric field distributions near the sulfide surface and correlation with underlying elemental heterogeneity. In this paper we discuss PIXE measurements made on the CSIRO Nuclear Microprobe and correlate elemental maps with laser beam induced current maps of the electric field distribution.

Fusion of Terrestrial and Airborne Laser Data for 3D modeling Applications

Science.gov (United States)

Mohammed, Hani Mahmoud

This thesis deals with the 3D modeling phase of the as-built large BIM projects. Among several means of BIM data capturing, such as photogrammetric or range tools, laser scanners have been one of the most efficient and practical tool for a long time. They can generate point clouds with high resolution for 3D models that meet nowadays' market demands. The current 3D modeling projects of as-built BIMs are mainly focused on using one type of laser scanner data, such as Airborne or Terrestrial. According to the literatures, no significant (few) efforts were made towards the fusion of heterogeneous laser scanner data despite its importance. The importance of the fusion of heterogeneous data arises from the fact that no single type of laser data can provide all the information about BIM, especially for large BIM projects that are existing on a large area, such as university buildings, or Heritage places. Terrestrial laser scanners are able to map facades of buildings and other terrestrial objects. However, they lack the ability to map roofs or higher parts in the BIM project. Airborne laser scanner on the other hand, can map roofs of the buildings efficiently and can map only small part of the facades. Short range laser scanners can map the interiors of the BIM projects, while long range scanners are used for mapping wide exterior areas in BIM projects. In this thesis the long range laser scanner data obtained in the Stop-and-Go mapping mode, the short range laser scanner data, obtained in a fully static mapping mode, and the airborne laser data are all fused together to bring a complete effective solution for a large BIM project. Working towards the 3D modeling of BIM projects, the thesis framework starts with the registration of the data, where a new fast automatic registration algorithm were developed. The next step is to recognize the different objects in the BIM project (classification), and obtain 3D models for the buildings. The last step is the development of an

Application of photoluminescence imaging and laser-beam-induced-current mapping in thin film solar cell characterization

Energy Technology Data Exchange (ETDEWEB)

Liu, Geyuan [Iowa State Univ., Ames, IA (United States)

2017-05-06

My research projects are focused on application of photonics, optics and micro- fabrication technology in energy related fields. Photonic crystal fabrication research has the potential to help us generate and use light more efficiently. In order to fabricate active 3D woodpile photonic structure devices, a woodpile template is needed to enable the crystal growth process. We developed a silica woodpile template fabrication process based on two polymer transfer molding technique. A silica woodpile template is demonstrated to work with temperature up to 900 C. It provides a more economical way to explore making better 3D active woodpile photonic devices like 3D photonic light emitting diodes (LED). Optical research on solar cell testing has the potential to make our energy generation more e cient and greener. PL imaging and LBIC mapping are used to measure CdTe solar cells with different back contacts. A strong correlation between PL image defects and LBIC map defects is observed. This opens up potential application for PL imaging in fast solar cell inspection. 2D laser IV scan shows its usage in 2D parameter mapping. We show its ability to generate important information about solar cell performance locally around PL image defects.

Asymptotic representation of relaxation oscillations in lasers

CERN Document Server

Grigorieva, Elena V

2017-01-01

In this book we analyze relaxation oscillations in models of lasers with nonlinear elements controlling light dynamics. The models are based on rate equations taking into account periodic modulation of parameters, optoelectronic delayed feedback, mutual coupling between lasers, intermodal interaction and other factors. With the aim to study relaxation oscillations we present the special asymptotic method of integration for ordinary differential equations and differential-difference equations. As a result, they are reduced to discrete maps. Analyzing the maps we describe analytically such nonlinear phenomena in lasers as multistability of large-amplitude relaxation cycles, bifurcations of cycles, controlled switching of regimes, phase synchronization in an ensemble of coupled systems and others. The book can be fruitful for students and technicians in nonlinear laser dynamics and in differential equations.

Lasers in medical applications: R and D mapping

International Nuclear Information System (INIS)

Deokattey, Sangeeta; Kalyane, V.L.; Kumar, Vijai; Phool Chand

2001-10-01

A study of the MEDLINE CDROM database, for the period 1969-2000 was undertaken. The purpose was, to identify core areas of research and development, in the field of applications of lasers to humans, along with other bibliometric indicators of research. A total of 34,833 records were retrieved, downloaded and analysed. The results indicate a steady increase in the number of publications every year, from 1970 onwards, with 1997 (2767 articles) and 1998 (2914 articles) being the most productive years. The most prolific contributors were J. Haut, with 95 publications to his credit, followed by M. Landthaler (82), G. Coscas (79), S.G. Bown (73) and P. Bjerring (70). Collaboration among the authors was high, with a maximum of 15 contributors observed in a few articles. The top ranking journal in the field was Ophthalmology, which published 769 articles starting from 1978. USA was way ahead as the country with the highest journal productivity (around 40% of the total number of records), followed by UK and Germany. A total of 103 articles were published from India. English was the preferred language of publication, with 75% of the records being published in English language. In the use of lasers for humans, maximum number of records were found for adult and middle aged populations. Research focussed on the eye and its various diseases. Lasers were found to be used for therapeutic purposes, in surgery and in the diagnosis of diseases. Carbon dioxide laser was most frequently used for medical applications. Though there were quite a few references on the adverse effects of lasers, the therapeutic effects far outweighed them. (author)

Mapping of the spatial distribution of silver nanoparticles in root tissues of Vicia faba by laser-induced breakdown spectroscopy (LIBS).

Science.gov (United States)

Krajcarová, L; Novotný, K; Kummerová, M; Dubová, J; Gloser, V; Kaiser, J

2017-10-01

The manuscript presents a procedure for optimal sample preparation and the mapping of the spatial distribution of metal ions and nanoparticles in plant roots using laser-induced breakdown spectroscopy (LIBS) in a double-pulse configuration (DP LIBS) in orthogonal reheating mode. Two Nd:YAG lasers were used; the first one was an ablation laser (UP-266 MACRO, New Wave, USA) with a wavelength of 266nm, and the second one (Brilliant, Quantel, France), with a fundamental wavelength of 1064nm, was used to reheat the microplasma. Seedlings of Vicia faba were cultivated for 7 days in CuSO 4 or AgNO 3 solutions with a concentration of 10µmoll -1 or in a solution of silver nanoparticles (AgNPs) with a concentration of 10µmoll -1 of total Ag, and in distilled water as a control. The total contents of the examined metals in the roots after sample mineralization as well as changes in the concentrations of the metals in the cultivation solutions were monitored by ICP-OES. Root samples embedded in the TissueTek medium and cut into 40µm thick cross sections using the Cryo-Cut Microtome proved to be best suited for an accurate LIBS analysis with a 50µm spatial resolution. 2D raster maps of elemental distribution were created for the emission lines of Cu(I) at 324.754nm and Ag(I) at 328.068nm. The limits of detection of DP LIBS for the root cross sections were estimated to be 4pg for Cu, 18pg for Ag, and 3pg for AgNPs. The results of Ag spatial distribution mapping indicated that unlike Ag + ions, AgNPs do not penetrate into the inner tissues of Vicia faba roots but stay in their outermost layers. The content of Ag in roots cultivated in the AgNP solution was one order of magnitude lower compared to roots cultivated in the metal ion solutions. The significantly smaller concentration of Ag in root tissues cultivated in the AgNP solution also supports the conclusion that the absorption and uptake of AgNPs by roots of Vicia faba is very slow. LIBS mapping of root sections

a Man-Portable Imu-Free Mobile Mapping System

Science.gov (United States)

Nüchter, A.; Borrmann, D.; Koch, P.; Kühn, M.; May, S.

2015-08-01

Mobile mapping systems are commonly mounted on cars, ships and robots. The data is directly geo-referenced using GPS data and expensive IMU (inertial measurement systems). Driven by the need for flexible, indoor mapping systems we present an inexpensive mobile mapping solution that can be mounted on a backpack. It combines a horizontally mounted 2D profiler with a constantly spinning 3D laser scanner. The initial system featuring a low-cost MEMS IMU was revealed and demonstrated at MoLaS: Technology Workshop Mobile Laser Scanning at Fraunhofer IPM in Freiburg in November 2014. In this paper, we present an IMU-free solution.

Evaluation of iTRAQ and SWATH-MS for the Quantification of Proteins Associated with Insulin Resistance in Human Duodenal Biopsy Samples.

Directory of Open Access Journals (Sweden)

Sylvie Bourassa

Full Text Available Insulin resistance (IR is associated with increased production of triglyceride-rich lipoproteins of intestinal origin. In order to assess whether insulin resistance affects the proteins involved in lipid metabolism, we used two mass spectrometry based quantitative proteomics techniques to compare the intestinal proteome of 14 IR patients to that of 15 insulin sensitive (IS control patients matched for age and waist circumference. A total of 3886 proteins were identified by the iTRAQ (Isobaric Tags for Relative and Absolute Quantitation mass spectrometry approach and 2290 by the SWATH-MS strategy (Serial Window Acquisition of Theoretical Spectra. Using these two methods, 208 common proteins were identified with a confidence corresponding to FDR < 1%, and quantified with p-value < 0.05. The quantification of those 208 proteins has a Pearson correlation coefficient (r2 of 0.728 across the two techniques. Gene Ontology analyses of the differentially expressed proteins revealed that annotations related to lipid metabolic process and oxidation reduction process are overly represented in the set of under-expressed proteins in IR subjects. Furthermore, both methods quantified proteins of relevance to IR. These data also showed that SWATH-MS is a promising and compelling alternative to iTRAQ for protein quantitation of complex mixtures.

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.

Multiple-Zone Diffractive Optic Element for Laser Ranging Applications

Science.gov (United States)

Ramos-Izquierdo, Luis A.

2011-01-01

A diffractive optic element (DOE) can be used as a beam splitter to generate multiple laser beams from a single input laser beam. This technology has been recently used in LRO s Lunar Orbiter Laser Altimeter (LOLA) instrument to generate five laser beams that measure the lunar topography from a 50-km nominal mapping orbit (see figure). An extension of this approach is to use a multiple-zone DOE to allow a laser altimeter instrument to operate over a wider range of distances. In particular, a multiple-zone DOE could be used for applications that require both mapping and landing on a planetary body. In this case, the laser altimeter operating range would need to extend from several hundred kilometers down to a few meters. The innovator was recently involved in an investigation how to modify the LOLA instrument for the OSIRIS asteroid mapping and sample return mission. One approach is to replace the DOE in the LOLA laser beam expander assembly with a multiple-zone DOE that would allow for the simultaneous illumination of the asteroid with mapping and landing laser beams. The proposed OSIRIS multiple-zone DOE would generate the same LOLA five-beam output pattern for high-altitude topographic mapping, but would simultaneously generate a wide divergence angle beam using a small portion of the total laser energy for the approach and landing portion of the mission. Only a few percent of the total laser energy is required for approach and landing operations as the return signal increases as the inverse square of the ranging height. A wide divergence beam could be implemented by making the center of the DOE a diffractive or refractive negative lens. The beam energy and beam divergence characteristics of a multiple-zone DOE could be easily tailored to meet the requirements of other missions that require laser ranging data. Current single-zone DOE lithographic manufacturing techniques could also be used to fabricate a multiple-zone DOE by masking the different DOE zones during

Precise Temporal Profiling of Signaling Complexes in Primary Cells Using SWATH Mass Spectrometry

Directory of Open Access Journals (Sweden)

Etienne Caron

2017-03-01

Full Text Available Spatiotemporal organization of protein interactions in cell signaling is a fundamental process that drives cellular functions. Given differential protein expression across tissues and developmental stages, the architecture and dynamics of signaling interaction proteomes is, likely, highly context dependent. However, current interaction information has been almost exclusively obtained from transformed cells. In this study, we applied an advanced and robust workflow combining mouse genetics and affinity purification (AP-SWATH mass spectrometry to profile the dynamics of 53 high-confidence protein interactions in primary T cells, using the scaffold protein GRB2 as a model. The workflow also provided a sufficient level of robustness to pinpoint differential interaction dynamics between two similar, but functionally distinct, primary T cell populations. Altogether, we demonstrated that precise and reproducible quantitative measurements of protein interaction dynamics can be achieved in primary cells isolated from mammalian tissues, allowing resolution of the tissue-specific context of cell-signaling events.

An overview of the laser ranging method of space laser altimeter

Science.gov (United States)

Zhou, Hui; Chen, Yuwei; Hyyppä, Juha; Li, Song

2017-11-01

Space laser altimeter is an active remote sensing instrument to measure topographic map of Earth, Moon and planetary. The space laser altimeter determines the range between the instrument and laser footprint by measuring round trip time of laser pulse. The return pulse reflected from ground surface is gathered by the receiver of space laser altimeter, the pulsewidth and amplitude of which are changeable with the variability of the ground relief. Meantime, several kinds of noise overlapped on the return pulse signal affect its signal-to-noise ratio. To eliminate the influence of these factors that cause range walk and range uncertainty, the reliable laser ranging methods need to be implemented to obtain high-precision range results. Based on typical space laser altimeters in the past few decades, various ranging methods are expounded in detail according to the operational principle of instruments and timing method. By illustrating the concrete procedure of determining time of flight of laser pulse, this overview provides the comparison of the employed technologies in previous and undergoing research programs and prospect innovative technology for space laser altimeters in future.

Return-map for semiconductor lasers with optical feedback

DEFF Research Database (Denmark)

Mørk, Jesper; Tromborg, Bjarne; Sabbatier, H.

1999-01-01

It is well known that a semiconductor laser exposed to moderate optical feedback and biased near threshold exhibits the phenomenon of low-frequency intensity fluctuations (LFF). While this behavior can be numerically simulated using the so-called Lang-Kobayshi model, the interpretation of the phe......It is well known that a semiconductor laser exposed to moderate optical feedback and biased near threshold exhibits the phenomenon of low-frequency intensity fluctuations (LFF). While this behavior can be numerically simulated using the so-called Lang-Kobayshi model, the interpretation...

3D mapping of turbulence: a laboratory experiment

Science.gov (United States)

Le Louarn, Miska; Dainty, Christopher; Paterson, Carl; Tallon, Michel

2000-07-01

In this paper, we present the first experimental results of the 3D mapping method. 3D mapping of turbulence is a method to remove the cone effect with multiple laser guide stars and multiple deformable mirrors. A laboratory experiment was realized to verify the theoretical predictions. The setup consisted of two turbulent phase screens (made with liquid crystal devices) and a Shack-Hartmann wavefront sensor. We describe the interaction matrix involved in reconstructing Zernike commands for multiple deformable mirror from the slope measurements made from laser guide stars. It is shown that mirror commands can indeed be reconstructed with the 3D mapping method. Limiting factors of the method, brought to light by this experiment are discussed.

Surface registration technique for close-range mapping applications

Science.gov (United States)

Habib, Ayman F.; Cheng, Rita W. T.

2006-08-01

Close-range mapping applications such as cultural heritage restoration, virtual reality modeling for the entertainment industry, and anatomical feature recognition for medical activities require 3D data that is usually acquired by high resolution close-range laser scanners. Since these datasets are typically captured from different viewpoints and/or at different times, accurate registration is a crucial procedure for 3D modeling of mapped objects. Several registration techniques are available that work directly with the raw laser points or with extracted features from the point cloud. Some examples include the commonly known Iterative Closest Point (ICP) algorithm and a recently proposed technique based on matching spin-images. This research focuses on developing a surface matching algorithm that is based on the Modified Iterated Hough Transform (MIHT) and ICP to register 3D data. The proposed algorithm works directly with the raw 3D laser points and does not assume point-to-point correspondence between two laser scans. The algorithm can simultaneously establish correspondence between two surfaces and estimates the transformation parameters relating them. Experiment with two partially overlapping laser scans of a small object is performed with the proposed algorithm and shows successful registration. A high quality of fit between the two scans is achieved and improvement is found when compared to the results obtained using the spin-image technique. The results demonstrate the feasibility of the proposed algorithm for registering 3D laser scanning data in close-range mapping applications to help with the generation of complete 3D models.

Femtosecond laser-induced herringbone patterns

Science.gov (United States)

Garcell, Erik M.; Lam, Billy; Guo, Chunlei

2018-06-01

Femtosecond laser-induced herringbone patterns are formed on copper (Cu). These novel periodic structures are created following s-polarized, large incident angle, femtosecond laser pulses. Forming as slanted and axially symmetric laser-induced periodic surface structures along the side walls of ablated channels, the result is a series of v-shaped structures that resemble a herringbone pattern. Fluence mapping, incident angle studies, as well as polarization studies have been conducted and provide a clear understanding of this new structure.

The Surface Water and Ocean Topography Satellite Mission - An Assessment of Swath Altimetry Measurements of River Hydrodynamics

Science.gov (United States)

Wilson, Matthew D.; Durand, Michael; Alsdorf, Douglas; Chul-Jung, Hahn; Andreadis, Konstantinos M.; Lee, Hyongki

2012-01-01

The Surface Water and Ocean Topography (SWOT) satellite mission, scheduled for launch in 2020 with development commencing in 2015, will provide a step-change improvement in the measurement of terrestrial surface water storage and dynamics. In particular, it will provide the first, routine two-dimensional measurements of water surface elevations, which will allow for the estimation of river and floodplain flows via the water surface slope. In this paper, we characterize the measurements which may be obtained from SWOT and illustrate how they may be used to derive estimates of river discharge. In particular, we show (i) the spatia-temporal sampling scheme of SWOT, (ii) the errors which maybe expected in swath altimetry measurements of the terrestrial surface water, and (iii) the impacts such errors may have on estimates of water surface slope and river discharge, We illustrate this through a "virtual mission" study for a approximately 300 km reach of the central Amazon river, using a hydraulic model to provide water surface elevations according to the SWOT spatia-temporal sampling scheme (orbit with 78 degree inclination, 22 day repeat and 140 km swath width) to which errors were added based on a two-dimension height error spectrum derived from the SWOT design requirements. Water surface elevation measurements for the Amazon mainstem as may be observed by SWOT were thereby obtained. Using these measurements, estimates of river slope and discharge were derived and compared to those which may be obtained without error, and those obtained directly from the hydraulic model. It was found that discharge can be reproduced highly accurately from the water height, without knowledge of the detailed channel bathymetry using a modified Manning's equation, if friction, depth, width and slope are known. Increasing reach length was found to be an effective method to reduce systematic height error in SWOT measurements.

Terrain Mapping and Classification in Outdoor Environments Using Neural Networks

OpenAIRE

Alberto Yukinobu Hata; Denis Fernando Wolf; Gustavo Pessin; Fernando Osório

2009-01-01

This paper describes a three-dimensional terrain mapping and classification technique to allow the operation of mobile robots in outdoor environments using laser range finders. We propose the use of a multi-layer perceptron neural network to classify the terrain into navigable, partially navigable, and non-navigable. The maps generated by our approach can be used for path planning, navigation, and local obstacle avoidance. Experimental tests using an outdoor robot and a laser sensor demonstra...

Laser Pyrometer For Spot Temperature Measurements

Science.gov (United States)

Elleman, D. D.; Allen, J. L.; Lee, M. C.

1988-01-01

Laser pyrometer makes temperature map by scanning measuring spot across target. Scanning laser pyrometer passively measures radiation emitted by scanned spot on target and calibrated by similar passive measurement on blackbody of known temperature. Laser beam turned on for active measurements of reflectances of target spot and reflectance standard. From measurements, temperature of target spot inferred. Pyrometer useful for non-contact measurement of temperature distributions in processing of materials.

Chinese HJ-1C SAR And Its Wind Mapping Capability

Science.gov (United States)

Huang, Weigen; Chen, Fengfeng; Yang, Jingsong; Fu, Bin; Chen, Peng; Zhang, Chan

2010-04-01

Chinese Huan Jing (HJ)-1C synthetic aperture radar (SAR) satellite has been planed to be launched in 2010. HJ-1C satellite will fly in a sun-synchronous polar orbit of 500-km altitude. SAR will be the only sensor on board the satellite. It operates in S band with VV polarization. Its image mode has the incidence angles 25°and 47°at the near and far sides of the swath respectively. There are two selectable SAR modes of operation, which are fine resolution beams and standard beams respectively. The sea surface wind mapping capability of the SAR has been examined using M4S radar imaging model developed by Romeiser. The model is based on Bragg scattering theory in a composite surface model expansion. It accounts for contributions of the full ocean wave spectrum to the radar backscatter from ocean surface. The model reproduces absolute normalized radar cross section (NRCS) values for wide ranges of wind speeds. The model results of HJ-1C SAR have been compared with the model results of Envisat ASAR. It shows that HJ-1C SAR is as good as Envisat ASAR at sea surface wind mapping.

Probabilistic mapping of flood-induced backscatter changes in SAR time series

Science.gov (United States)

Schlaffer, Stefan; Chini, Marco; Giustarini, Laura; Matgen, Patrick

2017-04-01

The information content of flood extent maps can be increased considerably by including information on the uncertainty of the flood area delineation. This additional information can be of benefit in flood forecasting and monitoring. Furthermore, flood probability maps can be converted to binary maps showing flooded and non-flooded areas by applying a threshold probability value pF = 0.5. In this study, a probabilistic change detection approach for flood mapping based on synthetic aperture radar (SAR) time series is proposed. For this purpose, conditional probability density functions (PDFs) for land and open water surfaces were estimated from ENVISAT ASAR Wide Swath (WS) time series containing >600 images using a reference mask of permanent water bodies. A pixel-wise harmonic model was used to account for seasonality in backscatter from land areas caused by soil moisture and vegetation dynamics. The approach was evaluated for a large-scale flood event along the River Severn, United Kingdom. The retrieved flood probability maps were compared to a reference flood mask derived from high-resolution aerial imagery by means of reliability diagrams. The obtained performance measures indicate both high reliability and confidence although there was a slight under-estimation of the flood extent, which may in part be attributed to topographically induced radar shadows along the edges of the floodplain. Furthermore, the results highlight the importance of local incidence angle for the separability between flooded and non-flooded areas as specular reflection properties of open water surfaces increase with a more oblique viewing geometry.

Fluorescence imaging of lattice re-distribution on step-index direct laser written Nd:YAG waveguide lasers

Energy Technology Data Exchange (ETDEWEB)

Martínez de Mendívil, Jon; Pérez Delgado, Alberto; Lifante, Ginés; Jaque, Daniel [Departamento de Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid 28049 (Spain); Ródenas, Airán [Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona 43007 (Spain); Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Benayas, Antonio, E-mail: antonio.benayas@emt.inrs.ca [Departamento de Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid 28049 (Spain); Institut National de la Recherche Scientifique, Centre – Énergie Matériaux et Télécommunications, 1650, Boul. Lionel Boulet Varennes, Quebec J3X 1S2 (Canada); Aguiló, Magdalena; Diaz, Francesc [Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona 43007 (Spain); Kar, Ajoy K. [Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)

2015-01-14

The laser performance and crystalline micro-structural properties of near-infrared step-index channel waveguides fabricated inside Neodymium doped YAG laser ceramics by means of three-dimensional sub-picosecond pulse laser direct writing are reported. Fluorescence micro-mapping of the waveguide cross-sections reveals that an essential crystal lattice re-distribution has been induced after short pulse irradiation. Such lattice re-distribution is evidenced at the waveguide core corresponding to the laser written refractive index increased volume. The waveguides core surroundings also present diverse changes including slight lattice disorder and bi-axial strain fields. The step-index waveguide laser performance is compared with previous laser fabricated waveguides with a stress-optic guiding mechanism in absence of laser induced lattice re-distribution.

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.

Temperature mapping of laser-induced hyperthermia in an ocular phantom using magnetic resonance thermography.

Science.gov (United States)

Maswadi, Saher M; Dodd, Stephen J; Gao, Jia-Hong; Glickman, Randolph D

2004-01-01

Laser-induced heating in an ocular phantom is measured with magnetic resonance thermography (MRT) using temperature-dependent phase changes in proton resonance frequency. The ocular phantom contains a layer of melanosomes isolated from bovine retinal pigment epithelium. The phantom is heated by the 806-nm output of a continuous wave diode laser with an irradiance of 2.4 to 21.6 W/cm2 in a beam radius of 0.8 or 2.4 mm, depending on the experiment. MRT is performed with a 2 T magnet, and a two-turn, 6-cm-diam, circular radio frequency coil. Two-dimensional temperature gradients are measured within the plane of the melanin layer, as well as normal to it, with a temperature resolution of 1 degrees C or better. The temperature gradients extending within the melanin layer are broader than those orthogonal to the layer, consistent with the higher optical absorption and consequent heating in the melanin. The temperature gradients in the phantom measured by MRT closely approximate the predictions of a classical heat diffusion model. Three-dimensional temperature maps with a spatial resolution of 0.25 mm in all directions are also made. Although the temporal resolution is limited in the prototype system (22.9 s for a single image "slice"), improvements in future implementations are likely. These results indicate that MRT has sufficient spatial and temperature resolution to monitor target tissue temperature during transpupillary thermotherapy in the human eye.

THE RAILMAPPER – A DEDICATED MOBILE LIDAR MAPPING SYSTEM FOR RAILWAY NETWORKS

Directory of Open Access Journals (Sweden)

J. Kremer

2012-07-01

Full Text Available The Mobile LiDAR Mapping System StreetMapper from IGI and 3D Laser Mapping (Bingham Nottingham, UK is mounted on a large variety of road vehicles to cover different mission specifications. In addition to the operation on the road, the system finds its applications on other kinds of vehicles, like boats or trains. The modular and flexible system concept even allows utilizing the same LiDAR Mapping system for Mobile Mapping on the ground and for airborne missions on helicopters, respectively. Besides this general flexibility, each application has its own special requirements. Special hardware and software components are needed to complete the core components, like the laser scanner and the GNSS/IMU systems, to build a dedicated system for the chosen task. Compared to the typical dynamics of a road vehicle mounted Mobile Mapping system, a dedicated rail mapping system operates under conditions that are much more challenging for a high accuracy GNSS/IMU trajectory determination. Furthermore, the typical rail mapping tasks, like the exact measurement of the rail track geometry, require the operation of the most accurate laser scanners and of specialized post-processing software. In this paper, the RailMapper, a specialized Mobile Mapping system for railway surveys is presented. The system is described with focus on the railway specific requirements and results of practical surveys are given.

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.

A versatile interaction chamber for laser-based spectroscopic applications, with the emphasis on Laser-Induced Breakdown Spectroscopy

International Nuclear Information System (INIS)

Novotný, J.; Brada, M.; Petrilak, M.; Prochazka, D.; Novotný, K.; Hrdička, A.; Kaiser, J.

2014-01-01

The technical note describes the interaction chamber developed particularly for the laser spectroscopy technique applications, such as Laser-Induced Breakdown Spectroscopy (LIBS), Raman Spectroscopy and Laser-Induced Fluorescence. The chamber was designed in order to provide advanced possibilities for the research in mentioned fields and to facilitate routine research procedures. Parameters and the main benefits of the chamber are described, such as the built-in module for automatic 2D chemical mapping and the possibility to set different ambient gas conditions (pressure value and gas type). Together with the chamber description, selected LIBS application examples benefiting from chamber properties are described. - Highlights: • Development of the interaction chamber for LIBS applications • Example of automated chemical mapping of lead in a chalcopyrite sample • Example of LIBS measurement of fluorine in underpressure • Overview of chamber benefits

NASA Space Laser Technology

Science.gov (United States)

Krainak, Michael A.

2015-01-01

Over the next two decades, the number of space based laser missions for mapping, spectroscopy, remote sensing and other scientific investigations will increase several fold. The demand for high wall-plug efficiency, low noise, narrow linewidth laser systems to meet different systems requirements that can reliably operate over the life of a mission will be high. The general trends will be for spatial quality very close to the diffraction limit, improved spectral performance, increased wall-plug efficiency and multi-beam processing. Improved spectral performance will include narrower spectral width (very near the transform limit), increased wavelength stability and or tuning (depending on application) and lasers reaching a wider range of wavelengths stretching into the mid-infrared and the near ultraviolet. We are actively developing high efficiency laser transmitter and high-sensitivity laser receiver systems that are suitable for spaceborne applications.

Progress in diode-pumped alexandrite lasers as a new resource for future space lidar missions

Science.gov (United States)

Damzen, M. J.; Thomas, G. M.; Teppitaksak, A.; Minassian, A.

2017-11-01

Satellite-based remote sensing using laser-based lidar techniques provides a powerful tool for global 3-D mapping of atmospheric species (e.g. CO2, ozone, clouds, aerosols), physical attributes of the atmosphere (e.g. temperature, wind speed), and spectral indicators of Earth features (e.g. vegetation, water). Such information provides a valuable source for weather prediction, understanding of climate change, atmospheric science and health of the Earth eco-system. Similarly, laser-based altimetry can provide high precision ground topography mapping and more complex 3-D mapping (e.g. canopy height profiling). The lidar technique requires use of cutting-edge laser technologies and engineered designs that are capable of enduring the space environment over the mission lifetime. The laser must operate with suitably high electrical-to-optical efficiency and risk reduction strategy adopted to mitigate against laser failure or excessive operational degradation of laser performance.

Studies into laser ignition of confined pyrotechnics

Energy Technology Data Exchange (ETDEWEB)

Ahmad, S.R.; Russell, D.A. [Centre for Applied Laser Spectroscopy, DASSR, Defence Academy, Cranfield University, Shrivenham, Swindon (United Kingdom)

2008-10-15

Ignition tests were carried out on three different pyrotechnics using laser energy from the multimode output from an Ar-Ion laser (av) at 500 nm and a near-IR diode laser pigtailed to a fibre optic cable and operating at 808 nm. The pyrotechnics investigated were: G20 black powder, SR44 and SR371C. The confined ignition tests were conducted in a specially designed ignition chamber. Pyrotechnics were ignited by a free space beam entering the chamber through an industrial sapphire window in the case of the Ar-ion laser. For the NIR diode laser, fibre was ducted through a block into direct contact with the pyrotechnic. The Ar-Ion laser was chosen as this was found to ignite all three pyrotechnics in the unconfined condition. It also allowed for a direct comparison of confined/unconfined results to be made. The threshold laser flux densities to initiate reproducible ignitions at this wavelength were found to be between {proportional_to}12.7 and {proportional_to}0.16 kW cm{sup -2}. Plotted on the ignition maps are the laser flux densities versus the start of ignition times for the three confined pyrotechnics. It was found from these maps that the times for confined ignition were substantially lower than those obtained for unconfined ignition under similar experimental conditions. For the NIR diode laser flux densities varied between {proportional_to}6.8 and {proportional_to}0.2 kW cm{sup -2}. The minimum ignition times for the NIR diode laser for SR371C ({proportional_to}11.2 ms) and G20 ({proportional_to}17.1 ms) were faster than those achieved by the use of the Ar-ion laser. However, the minimum ignition time was shorter ({proportional_to}11.7 ms) with the Ar-ion laser for SR44. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

A tool for NDVI time series extraction from wide-swath remotely sensed images

Science.gov (United States)

Li, Zhishan; Shi, Runhe; Zhou, Cong

2015-09-01

Normalized Difference Vegetation Index (NDVI) is one of the most widely used indicators for monitoring the vegetation coverage in land surface. The time series features of NDVI are capable of reflecting dynamic changes of various ecosystems. Calculating NDVI via Moderate Resolution Imaging Spectrometer (MODIS) and other wide-swath remotely sensed images provides an important way to monitor the spatial and temporal characteristics of large-scale NDVI. However, difficulties are still existed for ecologists to extract such information correctly and efficiently because of the problems in several professional processes on the original remote sensing images including radiometric calibration, geometric correction, multiple data composition and curve smoothing. In this study, we developed an efficient and convenient online toolbox for non-remote sensing professionals who want to extract NDVI time series with a friendly graphic user interface. It is based on Java Web and Web GIS technically. Moreover, Struts, Spring and Hibernate frameworks (SSH) are integrated in the system for the purpose of easy maintenance and expansion. Latitude, longitude and time period are the key inputs that users need to provide, and the NDVI time series are calculated automatically.

OMNIDIRECTIONAL PERCEPTION FOR LIGHTWEIGHT UAVS USING A CONTINUOUSLY ROTATING 3D LASER SCANNER

Directory of Open Access Journals (Sweden)

D. Droeschel

2013-08-01

Full Text Available Many popular unmanned aerial vehicles (UAV are restricted in their size and weight, making the design of sensory systems for these robots challenging. We designed a small and lightweight continuously rotating 3D laser scanner – allowing for environment perception in a range of 30 m in almost all directions. This sensor it well suited for applications such as 3D obstacle detection, 6D motion estimation, localization, and mapping. We aggregate the distance measurements in a robot-centric grid-based map. To estimate the motion of our multicopter, we register 3D laser scans towards this local map. In experiments, we compare the laser-based ego-motion estimate with ground-truth from a motion capture system. Overall, we can build an accurate 3D obstacle map and can estimate the vehicle's trajectory by 3D scan registration.

Design and optimisation of a pulsed CO2 laser for laser ultrasonics

CSIR Research Space (South Africa)

Forbes, A

2006-02-01

Full Text Available , resulting in a response at the material surface. This is detected and converted into a defect map across the aircraft. In this paper the authors consider the design and optimisation of a laser system for this application, and cover the basic science...

Mapping of multi-floor buildings: A barometric approach

DEFF Research Database (Denmark)

Özkil, Ali Gürcan; Fan, Zhun; Xiao, Jizhong

2011-01-01

This paper presents a new method for mapping multi5floor buildings. The method combines laser range sensor for metric mapping and barometric pressure sensor for detecting floor transitions and map segmentation. We exploit the fact that the barometric pressure is a function of the elevation......, and it varies between different floors. The method is tested with a real robot in a typical indoor environment, and the results show that physically consistent multi5floor representations are achievable....

Multi-sensors multi-baseline mapping system for mobile robot using stereovision camera and laser-range device

Directory of Open Access Journals (Sweden)

Mohammed Faisal

2016-06-01

Full Text Available Countless applications today are using mobile robots, including autonomous navigation, security patrolling, housework, search-and-rescue operations, material handling, manufacturing, and automated transportation systems. Regardless of the application, a mobile robot must use a robust autonomous navigation system. Autonomous navigation remains one of the primary challenges in the mobile-robot industry; many control algorithms and techniques have been recently developed that aim to overcome this challenge. Among autonomous navigation methods, vision-based systems have been growing in recent years due to rapid gains in computational power and the reliability of visual sensors. The primary focus of research into vision-based navigation is to allow a mobile robot to navigate in an unstructured environment without collision. In recent years, several researchers have looked at methods for setting up autonomous mobile robots for navigational tasks. Among these methods, stereovision-based navigation is a promising approach for reliable and efficient navigation. In this article, we create and develop a novel mapping system for a robust autonomous navigation system. The main contribution of this article is the fuse of the multi-baseline stereovision (narrow and wide baselines and laser-range reading data to enhance the accuracy of the point cloud, to reduce the ambiguity of correspondence matching, and to extend the field of view of the proposed mapping system to 180°. Another contribution is the pruning the region of interest of the three-dimensional point clouds to reduce the computational burden involved in the stereo process. Therefore, we called the proposed system multi-sensors multi-baseline mapping system. The experimental results illustrate the robustness and accuracy of the proposed system.

Temperature mapping using proton phase shift on a 0.3 T permanent magnet open MRI system

International Nuclear Information System (INIS)

Komura, Kazumi; Takahashi, Tetsuhiko; Dohi, Michiko; Harada, Junta

2000-01-01

Temperature mapping using proton phase shift (PPS) was evaluated for ex vivo objects. The evaluation was done on a 0.3 T permanent magnet open magnetic resonance imaging (MRI) machine, like those widely used for clinical diagnosis. Temperature maps were acquired using a gradient echo sequence (TR/TE =80/30 ms, flip angle =60 degrees, field of view =200 x 200 mm, slice thickness =8 mm, matrix size =128 x 128, data acquisition number =1, and imaging time =10.2 s). Specific first order data correction was performed to eliminate calculated temperature fluctuation due to magnetic field instability. A ham, 10 cm in diameter, was heated with a Nd: YAG laser with a wavelength of 1064 nm. The laser fiber was inserted into the ham to a depth of 3 cm. The laser power was 5, 8, or 10 W. Magnetic resonance images were taken continually during and after irradiation. Temperature maps were taken every 15 s. The maps taken during laser ablation showed color changes for the heated areas. Temperatures measured by the MRI and thermocouple had a linear relationship of r 2 =0.80. The inter-image standard deviation of the temperature maps of a non-heated object was 2.07 degrees for a 4.68 x 4.68 x 8 mm volume. This value is negligible for a monitored laser heating process since temperature rise is typically larger than 30 degrees. These results show that temperature mapping based on PPS is feasible for a 0.3 T permanent magnet open MRI system. (author)

Insertion, Validation, and Application of Barotropic and Baroclinic Tides in 1/12 and 1/25 Degree Global HYCOM

Science.gov (United States)

2013-09-30

implications for the development of the proposed wide-swath satellite altimeter (NASA/CNES SWOT mission). Three-dimensional maps of internal-wave driven...planned wide-swath satellite altimeter mission ( SWOT ). 4 --Conrad Luecke, graduate student in the UM Department of Earth and Environmental Sciences...harmonic analysis . If instead they are mostly non-stationary, then harmonic analysis will not suffice. In Figure 2 we display the non-stationarity as

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

Integrating laser-range finding, electronic compass measurements and GPS to rapidly map vertical changes in volcanic stratigraphy and constrain unit thicknesses and volumes: two examples from the northern Cordilleran volcanic province

Science.gov (United States)

Nogier, M.; Edwards, B. R.; Wetherell, K.

2005-12-01

We present preliminary results of laser-range finding-GPS surveys from two separate locations in northern British Columbia, in the south-central northern Cordilleran volcanic province: Hoodoo Mountain volcano and Craven Lake cone. This technique, described in detail below, is appropriate for rapidly measuring changes in vertical thicknesses of units that either would be difficult or impossible to measure by most other techniques. The ability to accurately measure thicknesses of geologic units in otherwise difficult-to-access locations will aide in generating better quantitative estimates of deposit geometries and eruption volumes. Such data is particularly important for constraining quantitative models of magma production and eruption dynamics. The deposits of interest in this study comprised at least partly inaccessible, largely pyroclastic units, although the technique could be used to map any vertical surfaces. The first field location was the northern side of Hoodoo Mountain volcano (56deg47'23.72'N/131deg17'36.97'W/1208m-asl), where a sequence of welded to unwelded, trachytic-phonolitic tephra was deposited in a paleovalley. This deposit is informally referred to as the Pointer Ridge deposit, and it comprises at least 7 distinct subunits. The horizontal limit of the exposures is approximately 1.5km, and the vertical limit is approximately 250m. Three different GPS base stations were used to map the lateral and vertical variations in the deposit. The second field location is north of Craven Lake (56deg54'44.55'N/129deg21'42.17'W/1453m-asl), along Craven Creek, where a sequence of basaltic tephra is overlain by pillow lava and glacial diamicton. This exposure is 200m long and approximately 30m high, much smaller than the area mapped at Hoodoo Mountain. The basaltic tephra appears to comprise 4 distinct sequences (measured thicknesses vary from 3-4m) not including the overlying pillow lava (measured thickness varies from 2 to 10m), and measurements of the

Geologic Map of the Greenaway Quadrangle (V-24), Venus

Science.gov (United States)

Lang, Nicholas P.; Hansen, Vicki L.

2010-01-01

The Greenaway quadrangle (V-24; lat 0 degrees -25 degrees N., long 120 degrees -150 degrees E.), Venus, derives its name from the impact crater Greenaway, centered at lat 22.9 degrees N., long 145.1 degrees E., in the northeastern part of the quadrangle. Greenaway was a well-noted writer and illustrator of children`s books in Britain during the nineteenth century. In Greenaway`s honor, the Library Association of Great Britain presents the annual Kate Greenaway Medal to an illustrator living and publishing in Britain who has produced the most distinguished children`s book illustrations for that year. The Greenaway quadrangle occupies an 8,400,000 km2 equatorial swath of lowlands and highlands. The map area is bounded by the crustal plateau, Thetis Regio, to the south and Gegute Tessera to the west. The rest of the quadrangle consists of part of Llorona Planitia, which is part of the vast lowlands that cover about 80 percent of Venus` surface. The southern map area marks the north edge of Aphrodite Terra, including Thetis Regio, that includes the highest topography in the quadrangle with elevations reaching >1 km above the Mean Planetary Radius (MPR; 6,051.84 km). Northern Aphrodite Terra abruptly slopes north to Llorona Planitia. A broad northeast-trending topographic arch pocked with coronae separates two northeast-trending elongate basins, Llorona Planitia on the east, that form depositional centers for shield and coronae-sourced materials; both basins drop to elevations of history for this region, which in turn provides insights into volcanic and tectonic processes that shaped the Venusian surface. Map relations illustrate that aerially expansive shield terrain (unit st) played a primary role and coronae played a secondary role in volcanic resurfacing across the map area.

CERES Clouds and Radiative Swath (CRS) data in HDF (CER_CRS_TRMM-PFM-VIRS_Edition2C)

Science.gov (United States)

Wielicki, Bruce A. (Principal Investigator)

The Clouds and Radiative Swath (CRS) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The CRS contains all of the CERES SSF product data. For each CERES footprint on the SSF the CRS also contains vertical flux profiles evaluated at four levels in the atmosphere: the surface, 500-, 70-, and 1-hPa. The CRS fluxes and cloud parameters are adjusted for consistency with a radiative transfer model and adjusted fluxes are evaluated at the four atmospheric levels for both clear-sky and total-sky. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2000-03-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

Field enhancement induced laser ablation

DEFF Research Database (Denmark)

Fiutowski, Jacek; Maibohm, Christian; Kjelstrup-Hansen, Jakob

Sub-diffraction spatially resolved, quantitative mapping of strongly localized field intensity enhancement on gold nanostructures via laser ablation of polymer thin films is reported. Illumination using a femtosecond laser scanning microscope excites surface plasmons in the nanostructures....... The accompanying field enhancement substantially lowers the ablation threshold of the polymer film and thus creates local ablation spots and corresponding topographic modifications of the polymer film. Such modifications are quantified straightforwardly via scanning electron and atomic force microscopy. Thickness...

Flying Fast and High: Operational Flight Planning for Maximum Data Return for Airborne Snow Observatory Mountain Surveys

Science.gov (United States)

Berisford, D. F.; Painter, T. H.; Richardson, M.; Wallach, A.; Deems, J. S.; Bormann, K. J.

2017-12-01

The Airborne Snow Observatory (ASO - http://aso.jpl.nasa.gov) uses an airborne laser scanner to map snow depth, and imaging spectroscopy to map snow albedo in order to estimate snow water equivalent and melt rate over mountainous, hydrologic basin-scale areas. Optimization of planned flight lines requires the balancing of many competing factors, including flying altitude and speed, bank angle limitation, laser pulse rate and power level, flightline orientation relative to terrain, surface optical properties, and data output requirements. These variables generally distill down to cost vs. higher resolution data. The large terrain elevation variation encountered in mountainous terrain introduces the challenge of narrow swath widths over the ridgetops, which drive tight flightline spacing and possible dropouts over the valleys due to maximum laser range. Many of the basins flown by ASO exceed 3,000m of elevation relief, exacerbating this problem. Additionally, sun angle may drive flightline orientations for higher-quality spectrometer data, which may change depending on time of day. Here we present data from several ASO missions, both operational and experimental, showing the lidar performance and accuracy limitations for a variety of operating parameters. We also discuss flightline planning strategies to maximize data density return per dollar, and a brief analysis on the effect of short turn times/steep bank angles on GPS position accuracy.

Imaging trench-line disruptions: Swath mapping of subduction zone

Digital Repository Service at National Institute of Oceanography (India)

Chakraborty, B.; Mukhopadhyay, R.

of the surveyed area. Generally, low b corr e sponds to rough seafloor, while S quantifies overall energy at a given area, i .e. for profiles ha v ing similar b but higher S will correspond to rougher profile. We extracted four evenly spaced depth... simulating reflector (BSR), often associated with the base of hydrate stability field. Physical parameters like porosity, density, thermal conductivity, temper a- ture, geothermal gradient, hydrate saturation, electr i- cal resistivity and heat flow...

Design and optimisation of a pulsed CO2 laser for laser ultrasonic applications

CSIR Research Space (South Africa)

Forbes, A

2006-07-01

Full Text Available at the material surface is detected and converted into a defect map across the aircraft. The design and optimization of a laser system for this application, together with the basic science involved, is reviewed in this paper. This includes the optimization...

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.

An Approach for High-Resolution Mapping of Hawaiian Metrosideros Forest Mortality Using Laser-Guided Imaging Spectroscopy

Directory of Open Access Journals (Sweden)

Nicholas R. Vaughn

2018-03-01

Full Text Available Rapid ‘Ōhi‘a Death (ROD is a disease aggressively killing large numbers of Metrosideros polymorpha (‘ōhi‘a, a native keystone tree species on Hawaii Island. This loss threatens to deeply alter the biological make-up of this unique island ecosystem. Spatially explicit information about the present and past advancement of the disease is essential for its containment; yet, currently such data are severely lacking. To this end, we used the Carnegie Airborne Observatory to collect Laser-Guided Imaging Spectroscopy data and high-resolution digital imagery across >500,000 ha of Hawaii Island in June–July 2017. We then developed a method to map individual tree crowns matching the symptoms of both active (brown; desiccated ‘ōhi‘a crowns and past (leafless tree crowns ROD infection using an ensemble of two distinct machine learning approaches. Employing a very conservative classification scheme for minimizing false-positives, model sensitivity rates were 86.9 and 82.5, and precision rates were 97.4 and 95.3 for browning and leafless crowns, respectively. Across the island of Hawaii, we found 43,134 individual crowns suspected of exhibiting the active (browning stage of ROD infection. Hotspots of potential ROD infection are apparent in the maps. The peninsula on the eastern side of Hawaii known as the Puna district, where the ROD outbreak likely originated, contained a particularly high density of brown crown detections. In comparison, leafless crown detections were much more numerous (547,666 detected leafless crowns in total and more dispersed across the island. Mapped hotspots of likely ROD incidence across the island will enable scientists, administrators, and land managers to better understand both where and how ROD spreads and how to apply limited resources to limiting this spread.

Using Terrestrial Laser Scanners to Calculate and Map Vertical Bridge Clearance

Science.gov (United States)

Zhang, C.; Arditi, D.; Chen, Z.

2013-08-01

The vertical clearance of a bridge over a highway is important in preventing oversized vehicles from hitting the bridge. The vertical clearance of a bridge is traditionally measured by using surveying equipment such as leveling rods and total stations. Typically, measurements are taken at multiple locations in order to determine the minimum vertical clearance under the bridge. This process is time and labor consuming. Also, these measurements may not be accurate because of the traffic, the uneven surface, and the reading error caused by the surveyor. Additionally, when one is faced with a multitude of reports especially in large projects with multiple ramps and bridges, it is not easy and it often takes a long time to find the bridge under study. This research provides a highly accurate measurement of the vertical bridge clearance by using terrestrial laser scanners. The clearance can be measured in the office by processing the collected point cloud data. The minimum vertical clearance is easily identified and the measurement is visualized and geo-referenced. An approach to reduce data noise caused by traffic is also introduced in this study. In addition, to help reduce the confusion of finding the bridge under study and to facilitate access to the clearance data, the clearance measurements are geo-referenced to an online mapping system. This system allows access to the final deliverable very easily through a single web portal. Finally, Illinois Department of Transportation's Circle Interchange is used to demonstrate this new method.

X-UV lasers and their promising applications

International Nuclear Information System (INIS)

Ros, D.

2004-01-01

The author reviews 30 years of research and achievements concerning X-UV lasers. Typical features of X-UV lasers are: a large number of photons emitted per impulse (between 10 12 and 10 14 ) and very short impulses (between 1 and 100 ps). When a crystal is irradiated by a X-UV laser, these features favor new physical processes that did not appear when the irradiation was performed with other X-UV sources like synchrotron radiation for instance. Their high brilliance and coherence properties make them efficient means as irradiating sources or imaging tools. X-UV laser interferometry allows the mapping of a surface at the nano-metric scale without any interaction between the laser beam and the surface. (A.C.)

Liquid chromatography, in combination with a quadrupole time-of-flight instrument (LC QTOF), with sequential window acquisition of all theoretical fragment-ion spectra (SWATH) acquisition: systematic studies on its use for screenings in clinical and forensic toxicology and comparison with information-dependent acquisition (IDA).

Science.gov (United States)

Roemmelt, Andreas T; Steuer, Andrea E; Poetzsch, Michael; Kraemer, Thomas

2014-12-02

Forensic and clinical toxicological screening procedures are employing liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques with information-dependent acquisition (IDA) approaches more and more often. It is known that the complexity of a sample and the IDA settings might prevent important compounds from being triggered. Therefore, data-independent acquisition (DIA) methods should be more suitable for systematic toxicological analysis (STA). The DIA method sequential window acquisition of all theoretical fragment-ion spectra (SWATH), which uses Q1 windows of 20-35 Da for data-independent fragmentation, was systematically investigated for its suitability for STA. Quality of SWATH-generated mass spectra were evaluated with regard to mass error, relative abundance of the fragments, and library hits. With the Q1 window set to 20-25 Da, several precursors pass Q1 at the same time and are fragmented, thus impairing the library search algorithms to a different extent: forward fit was less affected than reverse fit and purity fit. Mass error was not affected. The relative abundance of the fragments was concentration dependent for some analytes and was influenced by cofragmentation, especially of deuterated analogues. Also, the detection rate of IDA compared to SWATH was investigated in a forced coelution experiment (up to 20 analytes coeluting). Even using several different IDA settings, it was observed that IDA failed to trigger relevant compounds. Screening results of 382 authentic forensic cases revealed that SWATH's detection rate was superior to IDA, which failed to trigger ∼10% of the analytes.

High resolution laser beam induced current images under trichromatic laser radiation: approximation to the solar irradiation.

Science.gov (United States)

Navas, F J; Alcántara, R; Fernández-Lorenzo, C; Martín-Calleja, J

2010-03-01

A laser beam induced current (LBIC) map of a photoactive surface is a very useful tool when it is necessary to study the spatial variability of properties such as photoconverter efficiency or factors connected with the recombination of carriers. Obtaining high spatial resolution LBIC maps involves irradiating the photoactive surface with a photonic beam with Gaussian power distribution and with a low dispersion coefficient. Laser emission fulfils these characteristics, but against it is the fact that it is highly monochromatic and therefore has a spectral distribution different to solar emissions. This work presents an instrumental system and procedure to obtain high spatial resolution LBIC maps in conditions approximating solar irradiation. The methodology developed consists of a trichromatic irradiation system based on three sources of laser excitation with emission in the red, green, and blue zones of the electromagnetic spectrum. The relative irradiation powers are determined by either solar spectrum distribution or Planck's emission formula which provides information approximate to the behavior of the system if it were under solar irradiation. In turn, an algorithm and a procedure have been developed to be able to form images based on the scans performed by the three lasers, providing information about the photoconverter efficiency of photovoltaic devices under the irradiation conditions used. This system has been checked with three photosensitive devices based on three different technologies: a commercial silicon photodiode, a commercial photoresistor, and a dye-sensitized solar cell. These devices make it possible to check how the superficial quantum efficiency has areas dependent upon the excitation wavelength while it has been possible to measure global incident photon-to-current efficiency values approximating those that would be obtained under irradiation conditions with sunlight.

CERES Clouds and Radiative Swath (CRS) data in HDF. (CER_CRS_Terra-FM2-MODIS_Edition2B)

Science.gov (United States)

Wielicki, Bruce A. (Principal Investigator)

The Clouds and Radiative Swath (CRS) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The CRS contains all of the CERES SSF product data. For each CERES footprint on the SSF the CRS also contains vertical flux profiles evaluated at four levels in the atmosphere: the surface, 500-, 70-, and 1-hPa. The CRS fluxes and cloud parameters are adjusted for consistency with a radiative transfer model and adjusted fluxes are evaluated at the four atmospheric levels for both clear-sky and total-sky. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2001-10-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

CERES Clouds and Radiative Swath (CRS) data in HDF. (CER_CRS_Terra-FM2-MODIS_Edition2A

Science.gov (United States)

Wielicki, Bruce A. (Principal Investigator)

The Clouds and Radiative Swath (CRS) product contains one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The CRS contains all of the CERES SSF product data. For each CERES footprint on the SSF the CRS also contains vertical flux profiles evaluated at four levels in the atmosphere: the surface, 500-, 70-, and 1-hPa. The CRS fluxes and cloud parameters are adjusted for consistency with a radiative transfer model and adjusted fluxes are evaluated at the four atmospheric levels for both clear-sky and total-sky. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2001-10-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

Technology Development of a Fiber Optic-Coupled Laser Ignition System for Multi-Combustor Rocket Engines

Science.gov (United States)

Trinh, Huu P.; Early, Jim; Osborne, Robin; Thomas, Matthew E.; Bossard, John A.

2002-01-01

This paper addresses the progress of technology development of a laser ignition system at NASA Marshall Space Flight Center (MSFC). The first two years of the project focus on comprehensive assessments and evaluations of a novel dual-pulse laser concept, flight- qualified laser system, and the technology required to integrate the laser ignition system to a rocket chamber. With collaborations of the Department of Energy/Los Alamos National Laboratory (LANL) and CFD Research Corporation (CFDRC), MSFC has conducted 26 hot fire ignition tests with lab-scale laser systems. These tests demonstrate the concept feasibility of dual-pulse laser ignition to initiate gaseous oxygen (GOX)/liquid kerosene (RP-1) combustion in a rocket chamber. Presently, a fiber optic- coupled miniaturized laser ignition prototype is being implemented at the rocket chamber test rig for future testing. Future work is guided by a technology road map that outlines the work required for maturing a laser ignition system. This road map defines activities for the next six years, with the goal of developing a flight-ready laser ignition system.

Amplitude-modulated fiber-ring laser

DEFF Research Database (Denmark)

Caputo, J. G.; Clausen, Carl A. Balslev; Sørensen, Mads Peter

2000-01-01

Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self......-starting of stable solitonic pulses from small random noise, provided the modulation depth is small. The perturbative analysis leads to a nonlinear coupled return map for the amplitude, phase, and position of the soliton pulses circulating in the fiber-ring laser. We established the validity of this approach...

New Approaches to the Sea-Floor Mapping: Results From the GEBCO-NF Alumni Team's Technique Developments in Preparation to the Shell Ocean Discovery XPRIZE 2017.

Science.gov (United States)

Bazhenova, E.; Zarayskaya, Y.; Wigley, R. A.; Anderson, R.; Falconer, R. K. H.; Kearns, T.; Martin, T.; Minami, H.; Roperez, J.; Rosedee, A.; Sade, H.; Seeboruth, S.; Simpson, B.; Sumiyoshi, M.; Tinmouth, N.; Zwolak, K.

2017-12-01

In preparation for the XPRIZE 2017 Round 1, a new sea-floor mapping system has been assembled based on an Unmanned Surface Vessel (USV) coupled with an Autonomous Underwater Vehicle (AUV). USV operation allows reducing logistics costs, while the AUV provides enhanced maneuverability and high accuracy of stabilization for the mapping missions. The AUV is equipped with a high-resolution interferometric synthetic aperture sonar (HISAS) and a multibeam sonar (MBES), covering a wide bathymetry swath and the nadir, respectively. Typically operating at 20 to 40 m altitude, the HISAS is capable of providing SAS imagery with 4 x 4 cm resolution and bathymetry with 40 x 40 cm resolution throughout the swath. Smaller areas of interest (50 x 50 m) can be further examined using the Spot processing technique, to produce SAS imagery with 2 x 2 cm resolution and high- resolution SAS bathymetry with 5 x 5 cm resolution. This allows multi-aspect imaging and examination of seabed geological features at different scales. Advanced data post-processing can be performed to produce 3D images of objects and explore their structure using the shadow contrast and shape. Being an interferometric system, the HISAS collects data for both imagery and bathymetry in the same swath. This improves the robustness for SAS in areas with significant relief. In the standard survey mode, the HISAS can typically collect SAS data at 2.6 km2/hr over relatively flat ground. Another limiting factor to the HISAS data coverage and quality is the vehicle stability influenced by downslope and cross currents and the resulting vehicle's speed. From experience, the best coverage occurs at a vehicle speed of around 2 m/s. At slower speeds the vehicle starts to lose steerage leading to degradation of tracking and navigation performance, which harms the focusing algorithm that creates the SAS data. For the AUV mission planning in unknown areas or in case of highly variable conditions at the study site, MBES

Small signal gain measurements in a small scale HF overtone laser

Energy Technology Data Exchange (ETDEWEB)

Wisniewski, C.F.; Hewett, K.B.; Manke, G.C. II; Hager, G.D. [Air Force Research Laboratory, Directed Energy Directorate, 3550 Aberdeen Ave SE, Kirtland AFB, NM 87117-5776 (United States); Crowell, P.G. [Northrup Grumman Information Technology, Science and Technology Operating Unit, Advanced Technology Division, P.O. Box 9377, Albuquerque, NM 87119-9377 (United States); Truman, C.R. [Mechanical Engineering Department, University of New Mexico, Albuquerque, NM 87131 (United States)

2003-07-01

The overtone gain medium of a small-scale HF overtone laser was probed using a sub-Doppler tunable diode laser. Two-dimensional spatially resolved small signal gain and temperature maps were generated for several ro-vibrational transitions in the HF (v=2{yields}v=0) overtone band. Our results compare well with previous measurements of the overtone gain in a similar HF laser device. (orig.)

The California Seafloor Mapping Program — Providing science and geospatial data for California's State Waters

Science.gov (United States)

Johnson, S. Y.; Cochrane, G. R.; Golden, N. E.; Dartnell, P.; Hartwell, S. R.; Cochran, S. A.; Watt, J. T.

2017-12-01

The California Seafloor Mapping Program (CSMP) is a collaborative effort to develop comprehensive bathymetric, geologic, and habitat maps and data for California's State Waters, which extend for 1,350 km from the shoreline to 5.6 km offshore. CSMP began in 2007 when the California Ocean Protection Council and NOAA allocated funding for high-resolution bathymetric mapping to support the California Marine Life Protection Act and update nautical charts. Collaboration and support from the USGS and other partners has led to development and dissemination of one of the world's largest seafloor-mapping datasets. CSMP data collection includes: (1) High-resolution bathymetric and backscatter mapping using swath sonar sensors; (2) "Ground-truth" imaging from a sled mounted with video and still cameras; (3) High-resolution seismic-reflection profiling at 1 km line spacing. Processed data are all publicly available. Additionally, 25 USGS map and datasets covering one third of California's coast have been published. Each publication contains 9 to 12 pdf map sheets (1:24,000 scale), an explanatory pamphlet, and a catalog of digital geospatial data layers (about 15 to 25 per map area) with web services. Map sheets display bathymetry, backscatter, perspective views, habitats, groundtruth imagery, seismic profiles, sediment distribution and thickness, and onshore-offshore geology. The CSMP goal is to serve a large constituency, ranging from senior GIS analysts in large agencies, to local governments with limited resources, to non-governmental organizations, the private sector, and concerned citizens. CSMP data and publications provide essential science and data for ocean and coastal management, stimulate and enable research, and raise public education and awareness of coastal and ocean issues. Specific applications include: Delineation and designation of marine protected areas Characterization and modeling of benthic habitats and ecosystems Updating nautical charts Earthquake hazard

Status of mapping for pre-detailing and projects of pipelines

Energy Technology Data Exchange (ETDEWEB)

Gil, Fabio Vinicius Fontoura; Paoletto, Bonatto Silvia M. [ESTEIO Engenharia e Aerolevantamentos S.A, Curitiba, PR (Brazil)

2009-07-01

Considering the ever growing need for widening and supplying of the national energy matrix, ESTEIO Engenharia e Aerolevantamentos SA presents its participation in the Pipeline area, through Cartography activities, pointing out the performance on strips yet to be implanted, with activities as aerial survey, laser surveys, creation of orthophotomap, tracing definition, rivers crossing, geotechnical surveys, cadaster, creation of cadaster maps, strips, basic project drawings, imagery maps, as well as activities for existing strips, such as: aerial survey, laser surveys, strips enlargements, new property surveys, detection of pipelines through PCM technology, planimetric survey of equipment, besides activities for Pipeline Strips Geometry - FEED - pointing out the detailing of the areas which will be used for the dumping of the digging material and definition of accesses to the pipeline strips. We shall also present the technological evolution and consequent product improvements, considering surveys performed with conventional and digital aerial survey cameras, besides laser data. (author)

Coherent Doppler Laser Radar: Technology Development and Applications

Science.gov (United States)

Kavaya, Michael J.; Arnold, James E. (Technical Monitor)

2000-01-01

NASA's Marshall Space Flight Center has been investigating, developing, and applying coherent Doppler laser radar technology for over 30 years. These efforts have included the first wind measurement in 1967, the first airborne flights in 1972, the first airborne wind field mapping in 1981, and the first measurement of hurricane eyewall winds in 1998. A parallel effort at MSFC since 1982 has been the study, modeling and technology development for a space-based global wind measurement system. These endeavors to date have resulted in compact, robust, eyesafe lidars at 2 micron wavelength based on solid-state laser technology; in a factor of 6 volume reduction in near diffraction limited, space-qualifiable telescopes; in sophisticated airborne scanners with full platform motion subtraction; in local oscillator lasers capable of rapid tuning of 25 GHz for removal of relative laser radar to target velocities over a 25 km/s range; in performance prediction theory and simulations that have been validated experimentally; and in extensive field campaign experience. We have also begun efforts to dramatically improve the fundamental photon efficiency of the laser radar, to demonstrate advanced lower mass laser radar telescopes and scanners; to develop laser and laser radar system alignment maintenance technologies; and to greatly improve the electrical efficiency, cooling technique, and robustness of the pulsed laser. This coherent Doppler laser radar technology is suitable for high resolution, high accuracy wind mapping; for aerosol and cloud measurement; for Differential Absorption Lidar (DIAL) measurements of atmospheric and trace gases; for hard target range and velocity measurement; and for hard target vibration spectra measurement. It is also suitable for a number of aircraft operations applications such as clear air turbulence (CAT) detection; dangerous wind shear (microburst) detection; airspeed, angle of attack, and sideslip measurement; and fuel savings through

Laser microirradiation of cells

International Nuclear Information System (INIS)

Berns, M.W.; Kitzes, M.; Rattner, J.B.; Burt, J.; Meredith, S.

1979-01-01

The brief review outlines the technique of laser microbeam irradiation (260 - 700 nm) of cells to study ultrastructural changes. In combination with other techniques such as optical microscopy, electron microscopy and autoradiography structure and organization of chromosomes and nucleoli, chromosome stability, mechanisms of mitosis, gene mapping, cytoplasmic functions, and structure of nucleic acids are investigated

Applications of lasers in nuclear power plants

International Nuclear Information System (INIS)

Raj, Rupam; Sanyal, D.N.; Sil, Jaydeb

2013-01-01

Applications of lasers in nuclear power plants: Bellow lip cutting and high pressure feeder coupling stud (HPFC) cutting during en-masse coolant channel replacement (EMCCR) campaign at Narora Atomic Power Station Reactor 1 in May 2006; cutting of pressure tubes from Madras Atomic Power Station 1 (MAPS-1) for easy storage in April 2005; In-situ cutting of selected coolant channel S-7 at Kakrapar Atomic Power Station (KAPS-2) (cutting of 12 mm thick end fitting and 4 mm thick liner tube of stainless steel from inside) in January 2005; Development of a miniature cutting mechanism for steam generator tubes (14 mm i.d.) from inside, In-situ bellow repair for secondary shutdown system; LASER welding may be deployed for End shield of MAPS-1 leak repair

Mapping of electrophysiological response to transcranial infrared laser stimulation on the human brain in vivo measured by electroencephalography (Conference Presentation)

Science.gov (United States)

Wang, Xinlong; Reddy, Divya Dhandapani; Gonzalez-Lima, F.; Liu, Hanli

2017-02-01

Transcranial infrared laser stimulation (TILS) is a non-destructive and non-thermal photobiomodulation therapy or process on the human brain; TILS uses infrared light from lasers or LEDs and has gained increased recognition for its beneficial effects on a variety of neurological and psychological conditions. While the mechanism of TILS has been assumed to stem from cytochrome-c-oxidase (CCO), which is the last enzyme in the electron transportation chain and is the primary photoacceptor, no literature is found to report electrophysiological response to TILS. In this study, a 64-channel electroencephalography (EEG) system was employed to monitor electrophysiological activities from 15 healthy human participants before, during and after TILS. A placebo experimental protocol was also applied for rigorous comparison. After recording a 3-minute baseline, we applied a 1064-nm laser with a power of 3.5W on the right forehead of each human participant for 8 minutes, followed by a 5-minute recovery period. In 64-channel EEG data analysis, we utilized several methods (root mean square, principal component analysis followed by independent component analysis, permutation conditional mutual information, and time-frequency wavelet analysis) to reveal differences in electrophysiological response to TILS between the stimulated versus placebo group. The analyzed results were further investigated using general linear model and paired t-test to reveal statistically meaningful responses induced by TILS. Moreover, this study will provide spatial mapping of human electrophysiological and possibly neural network responses to TILS for first time, indicating the potential of EEG to be an effective method for monitoring neurological improvement induced by TILS.

Laser mobile mapping standards and applications in transportation.

Science.gov (United States)

2015-11-01

This report describes the work that was done to support the development of a chapter for the INDOT Survey Manual on Mobile : Mapping. The work includes experiments that were done, data that was collected, analysis that was carried out, and conclusion...

Use of roughness maps in visualisation of surfaces

DEFF Research Database (Denmark)

Seitavuopio, Paulus; Rantanen, Jukka; Yliruusi, Jouko

2005-01-01

monohydrate, theophylline anhydrate, sodium chloride and potassium chloride. The roughness determinations were made by a laser profilometer. The new matrix method gives detailed roughness maps, which are able to show local variations in surface roughness values and provide an illustrative picture...

High-resolution three-dimensional compositional imaging by double-pulse laser-induced breakdown spectroscopy

International Nuclear Information System (INIS)

Schiavo, C.; Grifoni, E.; Legnaioli, S.; Lorenzetti, G.; Poggialini, F.; Pagnotta, S.; Palleschi, V.; Menichetti, L.

2016-01-01

In this paper we present a new instrument specifically realized for high-resolution three-dimensional compositional analysis and mapping of materials. The instrument is based on the coupling of a Double-Pulse Laser-Induced Breakdown Spectroscopy (LIBS) instrument with an optical microscope. The compositional mapping of the samples is obtained by scanning the laser beam across the surface of the sample, while the in depth analysis is performed by sending multiple laser pulses on the same point. Depths of analysis of several tens of microns can be obtained. The instrument presented has definite advantages with respect to Laser Ablation-ICP Mass Spectrometry in many applications related to material analysis, biomedicine and environmental diagnostics. An application to the diagnostics of industrial ceramics is presented, demonstrating the feasibility of Double-Pulse LIBS Imaging and its advantages with respect to conventional single-pulse LIBS imaging.

Laser process for extended silicon thin film solar cells

International Nuclear Information System (INIS)

Hessmann, M.T.; Kunz, T.; Burkert, I.; Gawehns, N.; Schaefer, L.; Frick, T.; Schmidt, M.; Meidel, B.; Auer, R.; Brabec, C.J.

2011-01-01

We present a large area thin film base substrate for the epitaxy of crystalline silicon. The concept of epitaxial growth of silicon on large area thin film substrates overcomes the area restrictions of an ingot based monocrystalline silicon process. Further it opens the possibility for a roll to roll process for crystalline silicon production. This concept suggests a technical pathway to overcome the limitations of silicon ingot production in terms of costs, throughput and completely prevents any sawing losses. The core idea behind these thin film substrates is a laser welding process of individual, thin silicon wafers. In this manuscript we investigate the properties of laser welded monocrystalline silicon foils (100) by micro-Raman mapping and spectroscopy. It is shown that the laser beam changes the crystalline structure of float zone grown silicon along the welding seam. This is illustrated by Raman mapping which visualizes compressive stress as well as tensile stress in a range of - 147.5 to 32.5 MPa along the welding area.

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.

Comparison of the laser ablation process on Zn and Ti using pulsed digital holographic interferometry

Energy Technology Data Exchange (ETDEWEB)

Amer, E., E-mail: eynas.amer@ltu.se [Department of Applied Physics and Mechanical Engineering, Lulea University of Technology, SE-971 87 Lulea (Sweden); Gren, P.; Kaplan, A.F.H.; Sjoedahl, M. [Department of Applied Physics and Mechanical Engineering, Lulea University of Technology, SE-971 87 Lulea (Sweden); El Shaer, M. [Department of Engineering Physics and Mathematics, Faculty of Engineering, Zagazig University, Zagazig (Egypt)

2010-05-01

Pulsed digital holographic interferometry has been used to compare the laser ablation process of a Q-switched Nd-YAG laser pulse (wavelength 1064 nm, pulse duration 12 ns) on two different metals (Zn and Ti) under atmospheric air pressure. Digital holograms were recorded for different time delays using collimated laser light (532 nm) passed through the volume along the target. Numerical data of the integrated refractive index field were calculated and presented as phase maps. Intensity maps were calculated from the recorded digital holograms and are used to calculate the attenuation of the probing laser beam by the ablated plume. The different structures of the plume, namely streaks normal to the surface for Zn in contrast to absorbing regions for Ti, indicates that different mechanisms of laser ablation could happen for different metals for the same laser settings and surrounding gas. At a laser fluence of 5 J/cm{sup 2}, phase explosion appears to be the ablation mechanism in case of Zn, while for Ti normal vaporization seems to be the dominant mechanism.

Laser radar: historical prospective-from the East to the West

Science.gov (United States)

Molebny, Vasyl; McManamon, Paul; Steinvall, Ove; Kobayashi, Takao; Chen, Weibiao

2017-03-01

This article discusses the history of laser radar development in America, Europe, and Asia. Direct detection laser radar is discussed for range finding, designation, and topographic mapping of Earth and of extraterrestrial objects. Coherent laser radar is discussed for environmental applications, such as wind sensing and for synthetic aperture laser radar development. Gated imaging is discussed through scattering layers for military, medical, and security applications. Laser microradars have found applications in intravascular studies and in ophthalmology for vision correction. Ghost laser radar has emerged as a new technology in theoretical and simulation applications. Laser radar is now emerging as an important technology for applications such as self-driving cars and unmanned aerial vehicles. It is also used by police to measure speed, and in gaming, such as the Microsoft Kinect.

Delineating Beach and Dune Morphology from Massive Terrestrial Laser Scanning Data Using the Generic Mapping Tools

Science.gov (United States)

Zhou, X.; Wang, G.; Yan, B.; Kearns, T.

2016-12-01

Terrestrial laser scanning (TLS) techniques have been proven to be efficient tools to collect three-dimensional high-density and high-accuracy point clouds for coastal research and resource management. However, the processing and presenting of massive TLS data is always a challenge for research when targeting a large area with high-resolution. This article introduces a workflow using shell-scripting techniques to chain together tools from the Generic Mapping Tools (GMT), Geographic Resources Analysis Support System (GRASS), and other command-based open-source utilities for automating TLS data processing. TLS point clouds acquired in the beach and dune area near Freeport, Texas in May 2015 were used for the case study. Shell scripts for rotating the coordinate system, removing anomalous points, assessing data quality, generating high-accuracy bare-earth DEMs, and quantifying beach and sand dune features (shoreline, cross-dune section, dune ridge, toe, and volume) are presented in this article. According to this investigation, the accuracy of the laser measurements (distance from the scanner to the targets) is within a couple of centimeters. However, the positional accuracy of TLS points with respect to a global coordinate system is about 5 cm, which is dominated by the accuracy of GPS solutions for obtaining the positions of the scanner and reflector. The accuracy of TLS-derived bare-earth DEM is primarily determined by the size of grid cells and roughness of the terrain surface for the case study. A DEM with grid cells of 4m x 1m (shoreline by cross-shore) provides a suitable spatial resolution and accuracy for deriving major beach and dune features.

Geologic map of the Nepenthes Planum Region, Mars

Science.gov (United States)

Skinner, James A.; Tanaka, Kenneth L.

2018-03-26

This map product contains a map sheet at 1:1,506,000 scale that shows the geology of the Nepenthes Planum region of Mars, which is located between the cratered highlands that dominate the southern hemisphere and the less-cratered sedimentary plains that dominate the northern hemisphere.  The map region contains cone- and mound-shaped landforms as well as lobate materials that are morphologically similar to terrestrial igneous or mud vents and flows. This map is part of an informal series of small-scale (large-area) maps aimed at refining current understanding of the geologic units and structures that make up the highland-to-lowland transition zone. The map base consists of a controlled Thermal Emission Imaging System (THEMIS) daytime infrared image mosaic (100 meters per pixel resolution) supplemented by a Mars Orbiter Laser Altimeter (MOLA) digital elevation model (463 meters per pixel resolution). The map includes a Description of Map Units and a Correlation of Map Units that describes and correlates units identified across the entire map region. The geologic map was assembled using ArcGIS software by Environmental Systems Research Institute (http://www.esri.com). The ArcGIS project, geodatabase, base map, and all map components are included online as supplemental data.

Laser induced breakdown spectroscopy for applications in nuclear industry

International Nuclear Information System (INIS)

Suri, B.M.

2010-01-01

There are several analytical techniques employing laser spectroscopy - each with its own distinctive potential. Laser Induced Breakdown Spectroscopy (LIBS) is one such technique which is attractive in view of its relative compactness and simplicity (in configuration), remote and online analysis (with no sample handling requirement) and high spatial resolution allowing compositional map or homogeneity analysis. In this technique, a high power pulsed (mostly nanosecond) laser is employed to irradiate the sample causing spark emission, characteristics of the sample composition, which is collected using suitable optics and analysed spectroscopically. Remote and online capability is derived from long distance delivery of laser beams and collection of emitted light by fibres or conventional optics. Since laser can be focused sharply on the target, it can facilitate compositional mapping. Beam Technology Development Group at BARC had initiated work on LIBS of nuclear materials several years ago. Recently the challenge of online monitoring of radioactive waste vitrification plant in a hot cell has been taken up. The theoretical and experimental work done by the group related to instrument development, plasma characterization, quantitative compositional analysis of ternary alloys and uranium vitrified glass samples (comprising more than dozen elements) are described. The future plans for setting up online glass homogeneity monitoring facility are also described. This should fulfill an important demand for optimization of vitrification process. Various other demands of nuclear industry are also reviewed

Utilizing laser spectroscopy of noble gas tracers for mapping oil and gas deposits. Final technical report

International Nuclear Information System (INIS)

Schuessler, H.A.

1998-01-01

The research results have demonstrated that extending collinear fast beam laser spectroscopy to resonance-excitation field-ionization spectroscopy yielded a novel ultrasensitive method to identify minute amounts of radioactive and stable isotopes. The authors have mainly performed measurements involving the trace detection of the various isotopes of Kr, Tl and Xe. In particular the technique is capable to monitor the long-lived radioactive isotopes used as tracers in the well logging industry and also in the biosphere in a range, where nuclear radiation counting techniques do not have the required isotopic selectivity and sensitivity. The authors are working in two directions. Both applications are based on the ultra sensitive detection of 85 Kr, namely: trace detection of 85 Kr to map the reservoir structure of large oil fields; trace detection of 85 Kr in environmental air samples to monitor nuclear activities and nuclear materials processing on a global scale. The authors are in contact with the BP company for practically implementing the oil field related work and have asked for samples from their Alaskan fields

Local-scale flood mapping on vegetated floodplains from radiometrically calibrated airborne LiDAR data

DEFF Research Database (Denmark)

Malinowski, Radoslaw; Höfle, Bernhard; König, Kristina

2016-01-01

that can be used for classification of water surfaces. Following the laser footprint analysis, three classifiers, namely AdaBoost with Decision Tree, Naïve Bayes and Random Forest, were utilised to classify laser points into flooded and non-flooded classes and to derive the map of flooding extent...

Evaluating MERIS-Based Aquatic Vegetation Mapping in Lake Victoria

NARCIS (Netherlands)

Cheruiyot, E.K.; Mito, C.; Menenti, M.; Gorte, B.G.H.; Koenders, R.; Akdim, N.

2014-01-01

Delineation of aquatic plants and estimation of its surface extent are crucial to the efficient control of its proliferation, and this information can be derived accurately with fine resolution remote sensing products. However, small swath and low observation frequency associated with them may be

Texturing of polypropylene (PP) with nanosecond lasers

Science.gov (United States)

Riveiro, A.; Soto, R.; del Val, J.; Comesaña, R.; Boutinguiza, M.; Quintero, F.; Lusquiños, F.; Pou, J.

2016-06-01

Polypropylene (PP) is a biocompatible and biostable polymer, showing good mechanical properties that has been recently introduced in the biomedical field for bone repairing applications; however, its poor surface properties due to its low surface energy limit their use in biomedical applications. In this work, we have studied the topographical modification of polypropylene (PP) laser textured with Nd:YVO4 nanosecond lasers emitting at λ = 1064 nm, 532 nm, and 355 nm. First, optical response of this material under these laser wavelengths was determined. The application of an absorbing coating was also studied. The influence of the laser processing parameters on the surface modification of PP was investigated by means of statistically designed experiments. Processing maps to tailor the roughness, and wettability, the main parameters affecting cell adhesion characteristics of implants, were also determined. Microhardness measurements were performed to discern the impact of laser treatment on the final mechanical properties of PP.

A laser calibration system for the STAR TPC

CERN Document Server

Lebedev, A

2002-01-01

A Time Projection Chamber (TPC) is the primary tracking detector for the STAR experiment at RHIC. A laser calibration system was built to calibrate and monitor the TPC tracking performance. The laser system uses a novel design which produces approx 500 thin, ionizing beams distributed throughout the tracking volume. This new approach is significantly simpler than the traditional ones, and provides complete TPC coverage at a reduced cost. The laser system was used during the RHIC 2000 summer run to measure drift velocities with about 0.02% accuracy and to monitor the TPC performance. Calibration runs were made with and without a magnetic field to check B field map corrections.

Mapping lake level changes using ICESat/GLAS satellite laser altimetry data: a case study in arid regions of central Asia

Science.gov (United States)

Li, JunLi; Fang, Hui; Yang, Liao

2011-12-01

Lakes in arid regions of Central Asia act as essential components of regional water cycles, providing sparse but valuable water resource for the fragile ecological environments and human lives. Lakes in Central Asia are sensitive to climate change and human activities, and great changes have been found since 1960s. Mapping and monitoring these inland lakes would improve our understanding of mechanism of lake dynamics and climatic impacts. ICESat/GLAS satellite laser altimetry provides an efficient tool of continuously measuring lake levels in these poorly surveyed remote areas. An automated mapping scheme of lake level changes is developed based on GLAS altimetry products, and the spatial and temporal characteristics of 9 typical lakes in Central Asia are analyzed to validate the level accuracies. The results show that ICESat/GLAS has a good performance of lake level monitoring, whose patterns of level changes are the same as those of field observation, and the max differences between GLAS and field data is 3cm. Based on the results, it is obvious that alpine lakes are increasing greatly in lake levels during 2003-2009 due to climate change, while open lakes with dams and plain endorheic lakes decrease dramatically in water levels due to human activities, which reveals the overexploitation of water resource in Central Asia.

Thermoreflectance spectroscopy—Analysis of thermal processes in semiconductor lasers

Science.gov (United States)

Pierścińska, D.

2018-01-01

This review focuses on theoretical foundations, experimental implementation and an overview of experimental results of the thermoreflectance spectroscopy as a powerful technique for temperature monitoring and analysis of thermal processes in semiconductor lasers. This is an optical, non-contact, high spatial resolution technique providing high temperature resolution and mapping capabilities. Thermoreflectance is a thermometric technique based on measuring of relative change of reflectivity of the surface of laser facet, which provides thermal images useful in hot spot detection and reliability studies. In this paper, principles and experimental implementation of the technique as a thermography tool is discussed. Some exemplary applications of TR to various types of lasers are presented, proving that thermoreflectance technique provides new insight into heat management problems in semiconductor lasers and in particular, that it allows studying thermal degradation processes occurring at laser facets. Additionally, thermal processes and basic mechanisms of degradation of the semiconductor laser are discussed.

Laser irradiation of carbon–tungsten materials

International Nuclear Information System (INIS)

Marcu, A; Lungu, C P; Ursescu, D; Porosnicu, C; Grigoriu, C; Avotina, L; Kizane, G; Marin, A; Osiceanu, P; Grigorescu, C E A; Demitri, N

2014-01-01

Carbon–tungsten layers deposited on graphite by thermionic vacuum arc (TVA) were directly irradiated with a femtosecond terawatt laser. The morphological and structural changes produced in the irradiated area by different numbers of pulses were systematically explored, both along the spots and in their depths. Although micro-Raman and Synchrotron-x-ray diffraction investigations have shown no carbide formation, they have shown the unexpected presence of embedded nano-diamonds in the areas irradiated with high fluencies. Scanning electron microscopy images show a cumulative effect of the laser pulses on the morphology through the ablation process. The micro-Raman spatial mapping signalled an increased percentage of sp 3 carbon bonding in the areas irradiated with laser fluencies around the ablation threshold. In-depth x-ray photoelectron spectroscopy investigations suggested a weak cumulative effect on the percentage increase of the sp 2 -sp 3 transitions with the number of laser pulses just for nanometric layer thicknesses. (paper)

Semiconductor and ceramic microstructure made by single mode fiber laser

International Nuclear Information System (INIS)

Pawlak, R; Tomczyk, M; Walczak, M; Domagalski, P

2014-01-01

In the paper the results of micromachining of 3D microstructures of microsystems made from silicon and alumina ceramic using a single mode fiber laser (1064 nm) are presented. The quality of obtained structures and its smallest dimensions with acceptable maintained quality were examined. The influence of variable parameters of laser processing with changing of mapping scale on geometrical features of structures was identified.

Laser tracker error determination using a network measurement

International Nuclear Information System (INIS)

Hughes, Ben; Forbes, Alistair; Lewis, Andrew; Sun, Wenjuan; Veal, Dan; Nasr, Karim

2011-01-01

We report on a fast, easily implemented method to determine all the geometrical alignment errors of a laser tracker, to high precision. The technique requires no specialist equipment and can be performed in less than an hour. The technique is based on the determination of parameters of a geometric model of the laser tracker, using measurements of a set of fixed target locations, from multiple locations of the tracker. After fitting of the model parameters to the observed data, the model can be used to perform error correction of the raw laser tracker data or to derive correction parameters in the format of the tracker manufacturer's internal error map. In addition to determination of the model parameters, the method also determines the uncertainties and correlations associated with the parameters. We have tested the technique on a commercial laser tracker in the following way. We disabled the tracker's internal error compensation, and used a five-position, fifteen-target network to estimate all the geometric errors of the instrument. Using the error map generated from this network test, the tracker was able to pass a full performance validation test, conducted according to a recognized specification standard (ASME B89.4.19-2006). We conclude that the error correction determined from the network test is as effective as the manufacturer's own error correction methodologies

Synchronisation in the phase model of three coupled lasers

International Nuclear Information System (INIS)

Kuznetsov, A P; Sataev, I R; Tyuryukina, L V; Chernyshov, N Yu

2014-01-01

The problem of synchronisation of three lasers is considered within the phase approximation. The domains of complete synchronisation, partial synchronisation, two-frequency resonant regimes, and three-frequency quasi-periodicity have been found using bifurcation analysis, the method of Lyapunov exponent maps, and construction of phase portraits. The differences in the properties of a three-element chain and ring, as well as the influence of the coupling type, are discussed. (control of laser radiation parameters)

Forest biomass mapping from fusion of GEDI Lidar data and TanDEM-X InSAR data

Science.gov (United States)

Qi, W.; Hancock, S.; Armston, J.; Marselis, S.; Dubayah, R.

2017-12-01

Mapping forest above-ground biomass (hereafter biomass) can significantly improve our ability to assess the role of forest in terrestrial carbon budget and to analyze the ecosystem productivity. Global Ecosystem Dynamic Investigation (GEDI) mission will provide the most complete lidar observations of forest vertical structure and has the potential to provide global-scale forest biomass data at 1-km resolution. However, GEDI is intrinsically a sampling mission and will have a between-track spacing of 600 m. An increase in adjacent-swath distance and the presence of cloud cover may also lead to larger gaps between GEDI tracks. In order to provide wall-to-wall forest biomass maps, fusion algorithms of GEDI lidar data and TanDEM-X InSAR data were explored in this study. Relationship between biomass and lidar RH metrics was firstly developed and used to derive biomass values over GEDI tracks which were simulated using airborne lidar data. These GEDI biomass values were then averaged in each 1-km cell to represent the biomass density within that cell. Whereas for cells without any GEDI observations, regression models developed between GEDI-derived biomass and TDX InSAR variables were applied to predict biomass over those places. Based on these procedures, contiguous biomass maps were finally generated at 1-km resolution over three representative forest types. Uncertainties for these biomass maps were also estimated at 1 km following methods developed in Saarela et al. (2016). Our results indicated great potential of GEDI/TDX fusion for large-scale biomass mapping. Saarela, S., Holm, S., Grafstrom, A., Schnell, S., Naesset, E., Gregoire, T.G., Nelson, R.F., & Stahl, G. (2016). Hierarchical model-based inference for forest inventory utilizing three sources of information. Annals of Forest Science, 73, 895-910

3D Mapping for Urban and Regional Planning

DEFF Research Database (Denmark)

Bodum, Lars

2002-01-01

The process of mapping in 3D for urban and regional planning purposes is not an uncomplicated matter. It involves both the construction of a new data-model and new routines for the geometric modeling of the physical objects. This is due to the fact that most of the documentation until now has been...... registered and georeferenced to the 2D plan. This paper will outline a new method for 3D mapping where new LIDAR (laser-scanning) technology and additional 2D maps with attributes will be combined to create a 3D map of an urban area. The 3D map will afterwards be used in a real-time simulation system (also...... known as Virtual Reality system) for urban and regional planning purposes. This initiative will be implemented in a specific geographic region (North Jutland County in Denmark) by a new research centre at Aalborg University called Centre for 3D GeoInformation. The key question for this research team...

Performance Analysis of the Microsoft Kinect Sensor for 2D Simultaneous Localization and Mapping (SLAM Techniques

Directory of Open Access Journals (Sweden)

Kamarulzaman Kamarudin

2014-12-01

Full Text Available This paper presents a performance analysis of two open-source, laser scanner-based Simultaneous Localization and Mapping (SLAM techniques (i.e., Gmapping and Hector SLAM using a Microsoft Kinect to replace the laser sensor. Furthermore, the paper proposes a new system integration approach whereby a Linux virtual machine is used to run the open source SLAM algorithms. The experiments were conducted in two different environments; a small room with no features and a typical office corridor with desks and chairs. Using the data logged from real-time experiments, each SLAM technique was simulated and tested with different parameter settings. The results show that the system is able to achieve real time SLAM operation. The system implementation offers a simple and reliable way to compare the performance of Windows-based SLAM algorithm with the algorithms typically implemented in a Robot Operating System (ROS. The results also indicate that certain modifications to the default laser scanner-based parameters are able to improve the map accuracy. However, the limited field of view and range of Kinect’s depth sensor often causes the map to be inaccurate, especially in featureless areas, therefore the Kinect sensor is not a direct replacement for a laser scanner, but rather offers a feasible alternative for 2D SLAM tasks.

Covariance mapping of two-photon double core hole states in C 2 H 2 and C 2 H 6 produced by an x-ray free electron laser

International Nuclear Information System (INIS)

Mucke, M; Motomura, K; Bozek, J D; Schorb, S; Messerschmidt, M; Glownia, J M; Cryan, J P; Coffee, R N; Takahashi, O; Prince, K C; Feifel, R; Univ. of Gothenburg

2015-01-01

Few-photon ionization and relaxation processes in acetylene (C 2 H 2 ) and ethane (C 2 H 6 ) were investigated at the linac coherent light source x-ray free electron laser (FEL) at SLAC, Stanford using a highly efficient multi-particle correlation spectroscopy technique based on a magnetic bottle. The analysis method of covariance mapping has been applied and enhanced, allowing us to identify electron pairs associated with double core hole (DCH) production and competing multiple ionization processes including Auger decay sequences. The experimental technique and the analysis procedure are discussed in the light of earlier investigations of DCH studies carried out at the same FEL and at third generation synchrotron radiation sources. In particular, we demonstrate the capability of the covariance mapping technique to disentangle the formation of molecular DCH states which is barely feasible with conventional electron spectroscopy methods

A unified modeling approach for physical experiment design and optimization in laser driven inertial confinement fusion

Energy Technology Data Exchange (ETDEWEB)

Li, Haiyan [Mechatronics Engineering School of Guangdong University of Technology, Guangzhou 510006 (China); Huang, Yunbao, E-mail: Huangyblhy@gmail.com [Mechatronics Engineering School of Guangdong University of Technology, Guangzhou 510006 (China); Jiang, Shaoen, E-mail: Jiangshn@vip.sina.com [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Jing, Longfei, E-mail: scmyking_2008@163.com [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Tianxuan, Huang; Ding, Yongkun [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China)

2015-11-15

Highlights: • A unified modeling approach for physical experiment design is presented. • Any laser facility can be flexibly defined and included with two scripts. • Complex targets and laser beams can be parametrically modeled for optimization. • Automatically mapping of laser beam energy facilitates targets shape optimization. - Abstract: Physical experiment design and optimization is very essential for laser driven inertial confinement fusion due to the high cost of each shot. However, only limited experiments with simple structure or shape on several laser facilities can be designed and evaluated in available codes, and targets are usually defined by programming, which may lead to it difficult for complex shape target design and optimization on arbitrary laser facilities. A unified modeling approach for physical experiment design and optimization on any laser facilities is presented in this paper. Its core idea includes: (1) any laser facility can be flexibly defined and included with two scripts, (2) complex shape targets and laser beams can be parametrically modeled based on features, (3) an automatically mapping scheme of laser beam energy onto discrete mesh elements of targets enable targets or laser beams be optimized without any additional interactive modeling or programming, and (4) significant computation algorithms are additionally presented to efficiently evaluate radiation symmetry on the target. Finally, examples are demonstrated to validate the significance of such unified modeling approach for physical experiments design and optimization in laser driven inertial confinement fusion.

Design and spectroscopic reflectometry characterization of pulsed laser deposition combinatorial libraries

International Nuclear Information System (INIS)

Schenck, Peter K.; Bassim, Nabil D.; Otani, Makoto; Oguchi, Hiroyuki; Green, Martin L.

2007-01-01

The goal of the design of pulsed laser deposition (PLD) combinatorial library films is to optimize the compositional coverage of the films while maintaining a uniform thickness. The deposition pattern of excimer laser PLD films can be modeled with a bimodal cos n distribution. Deposited films were characterized using a spectroscopic reflectometer (250-1000 nm) to map the thickness of both single composition calibration films and combinatorial library films. These distribution functions were used to simulate the composition and thickness of multiple target combinatorial library films. The simulations were correlated with electron-probe microanalysis wavelength-dispersive spectroscopy (EPMA-WDS) composition maps. The composition and thickness of the library films can be fine-tuned by adjusting the laser spot size, fluence, background gas pressure, target geometry and other processing parameters which affect the deposition pattern. Results from compositionally graded combinatorial library films of the ternary system Al 2 O 3 -HfO 2 -Y 2 O 3 are discussed

Determining position inside building via laser rangefinder and handheld computer

Science.gov (United States)

Ramsey, Jr James L. [Albuquerque, NM; Finley, Patrick [Albuquerque, NM; Melton, Brad [Albuquerque, NM

2010-01-12

An apparatus, computer software, and a method of determining position inside a building comprising selecting on a PDA at least two walls of a room in a digitized map of a building or a portion of a building, pointing and firing a laser rangefinder at corresponding physical walls, transmitting collected range information to the PDA, and computing on the PDA a position of the laser rangefinder within the room.

Applying field mapping refractive beam shapers to improve holographic techniques

Science.gov (United States)

Laskin, Alexander; Williams, Gavin; McWilliam, Richard; Laskin, Vadim

2012-03-01

Performance of various holographic techniques can be essentially improved by homogenizing the intensity profile of the laser beam with using beam shaping optics, for example, the achromatic field mapping refractive beam shapers like πShaper. The operational principle of these devices presumes transformation of laser beam intensity from Gaussian to flattop one with high flatness of output wavefront, saving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field, negligible residual wave aberration, and achromatic design provides capability to work with several laser sources with different wavelengths simultaneously. Applying of these beam shapers brings serious benefits to the Spatial Light Modulator based techniques like Computer Generated Holography or Dot-Matrix mastering of security holograms since uniform illumination of an SLM allows simplifying mathematical calculations and increasing predictability and reliability of the imaging results. Another example is multicolour Denisyuk holography when the achromatic πShaper provides uniform illumination of a field at various wavelengths simultaneously. This paper will describe some design basics of the field mapping refractive beam shapers and optical layouts of their applying in holographic systems. Examples of real implementations and experimental results will be presented as well.

CMOS MAPS in a Homogeneous 3D Process for Charged Particle Tracking

CERN Document Server

Manazza, A; Manghisoni, M; Re, V; Traversi, G; Bettarini, S; Forti, F; Morsani, F; Rizzo, G; 10.1109/TNS.2014.2299341

2014-01-01

This work presents the characterization of deep n-well (DNW) CMOS monolithic active pixel sensors (MAPS) fabricated in a 130 nm homogeneous, vertically integrated technology. An evaluation of the 3D MAPS device performance, designed for application of the experiments at the future high luminosity colliders, is provided through the characterization of the prototypes, including tests with infrared (IR) laser, 55Fe and 90Sr sources. The radiation hardness study of the technology will also be presented together with its impact on 3D DNW MAPS performance.

Empirical evaluation of a practical indoor mobile robot navigation method using hybrid maps

DEFF Research Database (Denmark)

Özkil, Ali Gürcan; Fan, Zhun; Xiao, Jizhong

2010-01-01

This video presents a practical navigation scheme for indoor mobile robots using hybrid maps. The method makes use of metric maps for local navigation and a topological map for global path planning. Metric maps are generated as occupancy grids by a laser range finder to represent local information...... about partial areas. The global topological map is used to indicate the connectivity of the ‘places-of-interests’ in the environment and the interconnectivity of the local maps. Visual tags on the ceiling to be detected by the robot provide valuable information and contribute to reliable localization...... that the method is implemented successfully on physical robot in a hospital environment, which provides a practical solution for indoor navigation....

High-power laser source evaluation

International Nuclear Information System (INIS)

Back, C.A.; Decker, C.D.; Dipeso, G.J.; Gerassimenko, M.; Managan, R.A.; Serduke, F.J.D.; Simonson, G.F.; Suter, L.J.

1997-07-01

This document reports progress in these areas: EXPERIMENTAL RESULTS FROM NOVA: TAMPED XENON UNDERDENSE X-RAY EMITTERS; MODELING MULTI-KEV RADIATION PRODUCTION OF XENON-FILLED BERYLLIUM CANS; MAPPING A CALCULATION FROM LASNEX TO CALE; HOT X RAYS FROM SEEDED NIF CAPSULES; HOHLRAUM DEBRIS MEASUREMENTS AT NOVA; FOAM AND STRUCTURAL RESPONSE CALCULATIONS FOR NIF NEUTRON EXPOSURE SAMPLE CASE ASSEMBLY DESIGN; NON-IGNITION X-RAY SOURCE FLUENCE-AREA PRODUCTS FOR NUCLEAR EFFECTS TESTING ON NIF. Also appended are reprints of two papers. The first is on the subject of ''X-Ray Production in Laser-Heated Xe Gas Targets.'' The second is on ''Efficient Production and Applications of 2- to 10-keV X Rays by Laser-Heated Underdense Radiators.''

A technique for temperature mapping in fluorocarbon plasmas using planar laser-induced fluorescence of CF

International Nuclear Information System (INIS)

Steffens, Kristen L.; Sobolewski, Mark A.

2004-01-01

Planar laser-induced fluorescence measurements of CF A 2 Σ + -X 2 Π(1,0) were used to determine two-dimensional maps of rotational temperature in CF 4 plasmas. Measured rotational temperatures are expected to be in equilibrium with the gas temperature due to the long chemical lifetime of CF relative to the collision rate. Experiments were performed in the capacitively coupled Gaseous Electronics Conference rf reference cell at pressures from 26.7 Pa (200 mTorr) to 107 Pa (800 mTorr) and powers of 10 to 30 W deposited in the plasma. Temperatures, which ranged from 273±15 K to 480±15 K, were fairly axially symmetric and increased with pressure and power. All plasmas were coolest near the electrodes, which provided a substantial sink for heat in the plasma. Highest temperatures were found at a radial position near the edge of the electrodes. The strong temperature gradients observed in the plasmas can have serious effects on density measurements that probe a single rotational level, as well as on reaction rate constants and interpretation of density gradients. The effects of water-cooling the electrodes and the presence of a silicon wafer on temperature were also measured

Indoor radiation mapping using the Laser Assisted Ranging and Data System (LARADS). Innovative technology summary report

International Nuclear Information System (INIS)

1998-11-01

The US Department of Energy's (DOE's) nuclear facilities require characterization and documentation of the results as part of planning and decision-making for decontamination and decommissioning (D and D) projects and to release areas that have been cleaned up. Conducting radiation surveys of indoor and outdoor surfaces and generating accurate survey reports is an important component of the D and D program. The Laser Assisted Ranging and Data System (LARADS) is a characterization technology that provides real-time data on the location and concentration levels of radiological contamination. The system can be utilized with a number of available detection instruments and can be integrated with existing data analysis and mapping software technologies to generate superior quality survey data reports. This innovative technology is competitive with baseline technologies in terms of cost and survey times, but is much more flexible and provides more useful reports. The system also has the capability of electronically logging survey data, making it easy to store and retrieve. Such data are scientifically derived and not subject to interpretation. The LARADS is an extremely attractive alternative to manually generated survey data reports

Encoding and decoding messages with chaotic lasers

International Nuclear Information System (INIS)

Alsing, P.M.; Gavrielides, A.; Kovanis, V.; Roy, R.; Thornburg, K.S. Jr.

1997-01-01

We investigate the structure of the strange attractor of a chaotic loss-modulated solid-state laser utilizing return maps based on a combination of intensity maxima and interspike intervals, as opposed to those utilizing Poincare sections defined by the intensity maxima of the laser (I=0,Ie<0) alone. We find both experimentally and numerically that a simple, intrinsic relationship exists between an intensity maximum and the pair of preceding and succeeding interspike intervals. In addition, we numerically investigate encoding messages on the output of a chaotic transmitter laser and its subsequent decoding by a similar receiver laser. By exploiting the relationship between the intensity maxima and the interspike intervals, we demonstrate that the method utilized to encode the message is vital to the system close-quote s ability to hide the signal from unwanted deciphering. In this work alternative methods are studied in order to encode messages by modulating the magnitude of pumping of the transmitter laser and also by driving its loss modulation with more than one frequency. copyright 1997 The American Physical Society

Laser induced fluorescence of trapped molecular ions

International Nuclear Information System (INIS)

Winn, J.S.

1980-10-01

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

Plant equipment services with laser metrology

International Nuclear Information System (INIS)

Hayes, J.H.; Kreitman, P.J.

1995-01-01

A new industrial metrology process is now being applied to support PWR Nuclear Plant Steam Generator Replacement Projects. The method uses laser tracking interferometry to perform as built surveys of existing and replacement plant equipment. This method provides precision data with a minimum of setup when compared to alternative methods available. In addition there is no post processing required to ascertain validity. The data is obtained quickly, processed in real time and displayed during the survey in the desired coordinate system. These capabilities make this method of industrial measure ideal for various data acquisition needs throughout the power industry, from internal/external equipment templating to area mapping. Laser tracking interferometry is an improvement on the present use of optical instruments and surveying technique. In order to describe the laser tracking interferometry measurement process, previous methods of templating and surveying are first reviewed

Ferromanganese nodules from the Central Indian Ocean Basin

Digital Repository Service at National Institute of Oceanography (India)

Jauhari, P.; Pattan, J.N.

In order to delineate a mine site for ferromanganese nodules, extensive surveys were conducted in Central Indian Ocean Basin. Mapping of the basin by multibeam swath bathymetry (Hydrosweep) has revealed many new bottom relief features...

Distributed autonomous mapping of indoor environments

Science.gov (United States)

Rogers, J.; Paluri, M.; Cunningham, A.; Christensen, H. I.; Michael, N.; Kumar, V.; Ma, J.; Matthies, L.

2011-06-01

This paper describes the results of a Joint Experiment performed on behalf of the MAST CTA. The system developed for the Joint Experiment makes use of three robots which work together to explore and map an unknown environment. Each of the robots used in this experiment is equipped with a laser scanner for measuring walls and a camera for locating doorways. Information from both of these types of structures is concurrently incorporated into each robot's local map using a graph based SLAM technique. A Distributed-Data-Fusion algorithm is used to efficiently combine local maps from each robot into a shared global map. Each robot computes a compressed local feature map and transmits it to neighboring robots, which allows each robot to merge its map with the maps of its neighbors. Each robot caches the compressed maps from its neighbors, allowing it to maintain a coherent map with a common frame of reference. The robots utilize an exploration strategy to efficiently cover the unknown environment which allows collaboration on an unreliable communications channel. As each new branching point is discovered by a robot, it broadcasts the information about where this point is along with the robot's path from a known landmark to the other robots. When the next robot reaches a dead-end, new branching points are allocated by auction. In the event of communication interruption, the robot which observed the branching point will eventually explore it; therefore, the exploration is complete in the face of communication failure.

Mapping return currents in laser-generated Z-pinch plasmas using proton deflectometry

International Nuclear Information System (INIS)

Manuel, M. J.-E.; Sinenian, N.; Seguin, F. H.; Li, C. K.; Frenje, J. A.; Rinderknecht, H. G.; Casey, D. T.; Zylstra, A. B.; Petrasso, R. D.; Beg, F. N.

2012-01-01

Dynamic return currents and electromagnetic field structure in laser-generated Z-pinch plasmas have been measured using proton deflectometry. Experiments were modeled to accurately interpret deflections observed in proton radiographs. Current flow is shown to begin on axis and migrate outwards with the expanding coronal plasma. Magnetic field strengths of ∼1 T are generated by currents that increase from ∼2 kA to ∼7 kA over the course of the laser pulse. Proton deflectometry has been demonstrated to be a practical alternative to other magnetic field diagnostics for these types of plasmas.

SLAM-Aided Stem Mapping for Forest Inventory with Small-Footprint Mobile LiDAR

Directory of Open Access Journals (Sweden)

Jian Tang

2015-12-01

Full Text Available Accurately retrieving tree stem location distributions is a basic requirement for biomass estimation of forest inventory. Combining Inertial Measurement Units (IMU with Global Navigation Satellite Systems (GNSS is a commonly used positioning strategy in most Mobile Laser Scanning (MLS systems for accurate forest mapping. Coupled with a tactical or consumer grade IMU, GNSS offers a satisfactory solution in open forest environments, for which positioning accuracy better than one decimeter can be achieved. However, for such MLS systems, positioning in a mature and dense forest is still a challenging task because of the loss of GNSS signals attenuated by thick canopy. Most often laser scanning sensors in MLS systems are used for mapping and modelling rather than positioning. In this paper, we investigate a Simultaneous Localization and Mapping (SLAM-aided positioning solution with point clouds collected by a small-footprint LiDAR. Based on the field test data, we evaluate the potential of SLAM positioning and mapping in forest inventories. The results show that the positioning accuracy in the selected test field is improved by 38% compared to that of a traditional tactical grade IMU + GNSS positioning system in a mature forest environment and, as a result, we are able to produce a unambiguous tree distribution map.

A 2.5D Map-Based Mobile Robot Localization via Cooperation of Aerial and Ground Robots.

Science.gov (United States)

Nam, Tae Hyeon; Shim, Jae Hong; Cho, Young Im

2017-11-25

Recently, there has been increasing interest in studying the task coordination of aerial and ground robots. When a robot begins navigation in an unknown area, it has no information about the surrounding environment. Accordingly, for robots to perform tasks based on location information, they need a simultaneous localization and mapping (SLAM) process that uses sensor information to draw a map of the environment, while simultaneously estimating the current location of the robot on the map. This paper aims to present a localization method based in cooperation between aerial and ground robots in an indoor environment. The proposed method allows a ground robot to reach accurate destination by using a 2.5D elevation map built by a low-cost RGB-D (Red Green and Blue-Depth) sensor and 2D Laser sensor attached onto an aerial robot. A 2.5D elevation map is formed by projecting height information of an obstacle using depth information obtained by the RGB-D sensor onto a grid map, which is generated by using the 2D Laser sensor and scan matching. Experimental results demonstrate the effectiveness of the proposed method for its accuracy in location recognition and computing speed.

A 2.5D Map-Based Mobile Robot Localization via Cooperation of Aerial and Ground Robots

Directory of Open Access Journals (Sweden)

Tae Hyeon Nam

2017-11-01

Full Text Available Recently, there has been increasing interest in studying the task coordination of aerial and ground robots. When a robot begins navigation in an unknown area, it has no information about the surrounding environment. Accordingly, for robots to perform tasks based on location information, they need a simultaneous localization and mapping (SLAM process that uses sensor information to draw a map of the environment, while simultaneously estimating the current location of the robot on the map. This paper aims to present a localization method based in cooperation between aerial and ground robots in an indoor environment. The proposed method allows a ground robot to reach accurate destination by using a 2.5D elevation map built by a low-cost RGB-D (Red Green and Blue-Depth sensor and 2D Laser sensor attached onto an aerial robot. A 2.5D elevation map is formed by projecting height information of an obstacle using depth information obtained by the RGB-D sensor onto a grid map, which is generated by using the 2D Laser sensor and scan matching. Experimental results demonstrate the effectiveness of the proposed method for its accuracy in location recognition and computing speed.

Sensors Fusion based Online Mapping and Features Extraction of Mobile Robot in the Road Following and Roundabout

International Nuclear Information System (INIS)

Ali, Mohammed A H; Yussof, Wan Azhar B.; Hamedon, Zamzuri B; Yussof, Zulkifli B.; Majeed, Anwar P P; Mailah, Musa

2016-01-01

A road feature extraction based mapping system using a sensor fusion technique for mobile robot navigation in road environments is presented in this paper. The online mapping of mobile robot is performed continuously in the road environments to find the road properties that enable the robot to move from a certain start position to pre-determined goal while discovering and detecting the roundabout. The sensors fusion involving laser range finder, camera and odometry which are installed in a new platform, are used to find the path of the robot and localize it within its environments. The local maps are developed using camera and laser range finder to recognize the roads borders parameters such as road width, curbs and roundabout. Results show the capability of the robot with the proposed algorithms to effectively identify the road environments and build a local mapping for road following and roundabout. (paper)

LSNR Airborne LIDAR Mapping System Design and Early Results (Invited)

Science.gov (United States)

Shrestha, K.; Carter, W. E.; Slatton, K. C.

2009-12-01

Low signal-to-noise ratio (LSNR) detection techniques allow for implementation of airborne light detection and range (LIDAR) instrumentation aboard platforms with prohibitive power, size, and weight restrictions. The University of Florida has developed the Coastal Area Tactical-mapping System (CATS), a prototype LSNR LIDAR system capable of single photon laser ranging. CATS is designed to operate in a fixed-wing aircraft flying 600 m above ground level, producing 532 nm, 480 ps, 3 μJ output pulses at 8 kHz. To achieve continuous coverage of the terrain with 20 cm spatial resolution in a single pass, a 10x10 array of laser beamlets is scanned. A Risley prism scanner (two rotating V-coated optical wedges) allows the array of laser beamlets to be deflected in a variety of patterns, including conical, spiral, and lines at selected angles to the direction of flight. Backscattered laser photons are imaged onto a 100 channel (10x10 segmented-anode) photomultiplier tube (PMT) with a micro-channel plate (MCP) amplifier. Each channel of the PMT is connected to a multi-stop 2 GHz event timer. Here we report on tests in which ranges for known targets were accumulated for repeated laser shots and statistical analyses were applied to evaluate range accuracy, minimum separation distance, bathymetric mapping depth, and atmospheric scattering. Ground-based field test results have yielded 10 cm range accuracy and sub-meter feature identification at variable scan settings. These experiments also show that a secondary surface can be detected at a distance of 15 cm from the first. Range errors in secondary surface identification for six separate trials were within 7.5 cm, or within the timing resolution limit of the system. Operating at multi-photon sensitivity may have value for situations in which high ambient noise precludes single-photon sensitivity. Low reflectivity targets submerged in highly turbid waters can cause detection issues. CATS offers the capability to adjust the

Automatic Registration of Vehicle-borne Mobile Mapping Laser Point Cloud and Sequent Panoramas

Directory of Open Access Journals (Sweden)

CHEN Chi

2018-02-01

Full Text Available An automatic registration method of mobile mapping system laser point cloud and sequence panoramic image is proposed in this paper.Firstly,hierarchical object extraction method is applied on LiDAR data to extract the building façade and outline polygons are generated to construct the skyline vectors.A virtual imaging method is proposed to solve the distortion on panoramas and corners on skylines are further detected on the virtual images combining segmentation and corner detection results.Secondly,the detected skyline vectors are taken as the registration primitives.Registration graphs are built according to the extracted skyline vector and further matched under graph edit distance minimization criteria.The matched conjugate primitives are utilized to solve the 2D-3D rough registration model to obtain the initial transformation between the sequence panoramic image coordinate system and the LiDAR point cloud coordinate system.Finally,to reduce the impact of registration primitives extraction and matching error on the registration results,the optimal transformation between the multi view stereo matching dens point cloud generated from the virtual imaging of the sequent panoramas and the LiDAR point cloud are solved by a 3D-3D ICP registration algorithm variant,thus,refine the exterior orientation parameters of panoramas indirectly.Experiments are undertaken to validate the proposed method and the results show that 1.5 pixel level registration results are achieved on the experiment dataset.The registration results can be applied to point cloud and panoramas fusion applications such as true color point cloud generation.

Cyclone: A laser scanner for mobile robot navigation

Science.gov (United States)

Singh, Sanjiv; West, Jay

1991-09-01

Researchers at Carnegie Mellon's Field Robotics Center have designed and implemented a scanning laser rangefinder. The device uses a commercially available time-of-flight ranging instrument that is capable of making up to 7200 measurements per second. The laser beam is reflected by a rotating mirror, producing up to a 360 degree view. Mounted on a robot vehicle, the scanner can be used to detect obstacles in the vehicle's path or to locate the robot on a map. This report discusses the motivation, design, and some applications of the scanner.

Advanced wavefront measurement and analysis of laser system modeling

Energy Technology Data Exchange (ETDEWEB)

Wolfe, C.R.; Auerback, J.M. [Lawrence Livermore National Lab., CA (United States)

1994-11-15

High spatial resolution measurements of the reflected or transmitted wavefronts of large aperture optical components used in high peak power laser systems is now possible. These measurements are produced by phase shifting interferometry. The wavefront data is in the form of 3-D phase maps that reconstruct the wavefront shape. The emphasis of this work is on the characterization of wavefront features in the mid-spatial wavelength range (from 0.1 to 10.0 mm) and has been accomplished for the first time. Wavefront structure from optical components with spatial wavelengths in this range are of concern because their effects in high peak power laser systems. At high peak power, this phase modulation can convert to large magnitude intensity modulation by non-linear processes. This can lead to optical damage. We have developed software to input the measured phase map data into beam propagation codes in order to model this conversion process. We are analyzing this data to: (1) Characterize the wavefront structure produced by current optical components, (2) Refine our understanding of laser system performance, (3) Develop a database from which future optical component specifications can be derived.

Seafloor Mapping: We've Come a Long Way - But Still Have Far to Go……

Science.gov (United States)

Mayer, L. A.

2017-12-01

Our ability to map the seafloor has changed radically over the past century. For thousands of years a weight at the end of a rope (or wire) - a lead line - provided the only means to measure depth. By the end of the Second World War, single beam echo sounders had been perfected to the extent that they became common on oceanographic and other vessels providing more rapid but laterally averaged (typically over a distance commensurate with the water depth) measurements of seafloor depths. Towards the end of the 20th Century - two great advances were made in seafloor mapping - the development of techniques to use satellite altimetry to predict seafloor bathymetry and the evolution of multibeam sonar technology from classified military applications to the academic and commercial communities. Satellite-altimetry derived bathymetry provides an unprecedented view of seafloor topography and tremendous insight into tectonic-scale processes but is limited in achievable resolution. Multibeam sonars offer the potential of extremely high-resolution (a function of array size, beam footprint, and water depth), but are typically deployed from manned surface vessels that cover limited amount of seafloor at a relatively high daily cost. We have the technology to map the entire world ocean with multibeam sonar but It has been estimated that to map the world ocean deeper than about 150m (shallow water is very time-consuming and expensive because the coverage swath width is typically 3-5 times water) would take approximately 200 ship years and cost on the order of 3 billion dollars. We have demonstrated our willingness to spend billions to map other planets (e.g. Mars and the Moon) but for some reason, not our own. Recently, however, there has been growing momentum to see the entire world ocean mapped. The Nippon Foundation and GEBCO have recently announced the Seabed 2030 project with a goal of facilitating the mapping of the world ocean by 2030 and international agreements like The

Route to broadband chaos in a chaotic laser diode subject to optical injection.

Science.gov (United States)

Wang, An-Bang; Wang, Yun-Cai; Wang, Juan-Fen

2009-04-15

We experimentally and numerically demonstrate a route to bandwidth-enhanced chaos that is induced by an additional optical injection for a chaotic laser diode with optical feedback. The measured and calculated optical spectra consistently reveal that the mechanism of bandwidth enhancement is the interaction between the injection and chaotic laser field via beating. The bandwidth can be maximized only when the injected light is detuned into the edge of the optical spectrum of the chaotic laser field and the beating frequency exceeds the original bandwidth. The simulated dynamics maps indicate that 20 GHz broadband chaos can be obtained by commonly used laser diodes.

Exact extraction method for road rutting laser lines

Science.gov (United States)

Hong, Zhiming

2018-02-01

This paper analyzes the importance of asphalt pavement rutting detection in pavement maintenance and pavement administration in today's society, the shortcomings of the existing rutting detection methods are presented and a new rutting line-laser extraction method based on peak intensity characteristic and peak continuity is proposed. The intensity of peak characteristic is enhanced by a designed transverse mean filter, and an intensity map of peak characteristic based on peak intensity calculation for the whole road image is obtained to determine the seed point of the rutting laser line. Regarding the seed point as the starting point, the light-points of a rutting line-laser are extracted based on the features of peak continuity, which providing exact basic data for subsequent calculation of pavement rutting depths.

Laser altimeter measurements at Walnut Gulch Watershed, Arizona

International Nuclear Information System (INIS)

Ritchie, J.C.; Humes, K.S.; Weltz, M.A.

1995-01-01

Measurements of landscape surface roughness properties are necessary for understanding many watershed processes. This paper reviews the use of an airborne laser altimeter to measure topography and surface roughness properties of the landscape at Walnut Gulch Watershed in Arizona. Airborne laser data were used to measure macro and micro topography as well as canopy topography, height, cover, and distribution. Macro topography of landscape profiles for segments up to 5 km (3 mi) were measured and were in agreement with available topographic maps but provided more detail. Gullies and stream channel cross-sections and their associated floodplains were measured. Laser measurements of vegetation properties (height and cover) were highly correlated with ground measurements. Landscape segments for any length can be used to measure these landscape roughness properties. Airborne laser altimeter measurements of landscape profiles can provide detailed information on watershed surface properties for improving the management of watersheds. (author)

A multi-model ensemble approach to seabed mapping

Science.gov (United States)

Diesing, Markus; Stephens, David

2015-06-01

Seabed habitat mapping based on swath acoustic data and ground-truth samples is an emergent and active marine science discipline. Significant progress could be achieved by transferring techniques and approaches that have been successfully developed and employed in such fields as terrestrial land cover mapping. One such promising approach is the multiple classifier system, which aims at improving classification performance by combining the outputs of several classifiers. Here we present results of a multi-model ensemble applied to multibeam acoustic data covering more than 5000 km2 of seabed in the North Sea with the aim to derive accurate spatial predictions of seabed substrate. A suite of six machine learning classifiers (k-Nearest Neighbour, Support Vector Machine, Classification Tree, Random Forest, Neural Network and Naïve Bayes) was trained with ground-truth sample data classified into seabed substrate classes and their prediction accuracy was assessed with an independent set of samples. The three and five best performing models were combined to classifier ensembles. Both ensembles led to increased prediction accuracy as compared to the best performing single classifier. The improvements were however not statistically significant at the 5% level. Although the three-model ensemble did not perform significantly better than its individual component models, we noticed that the five-model ensemble did perform significantly better than three of the five component models. A classifier ensemble might therefore be an effective strategy to improve classification performance. Another advantage is the fact that the agreement in predicted substrate class between the individual models of the ensemble could be used as a measure of confidence. We propose a simple and spatially explicit measure of confidence that is based on model agreement and prediction accuracy.

Analysis of terrain map matching using multisensing techniques for applications to autonomous vehicle navigation

Science.gov (United States)

Page, Lance; Shen, C. N.

1991-01-01

This paper describes skyline-based terrain matching, a new method for locating the vantage point of laser range-finding measurements on a global map previously prepared by satellite or aerial mapping. Skylines can be extracted from the range-finding measurements and modelled from the global map, and are represented in parametric, cylindrical form with azimuth angle as the independent variable. The three translational parameters of the vantage point are determined with a three-dimensional matching of these two sets of skylines.

Beam shaping to provide round and square-shaped beams in optical systems of high-power lasers

Science.gov (United States)

Laskin, Alexander; Laskin, Vadim

2016-05-01

Optical systems of modern high-power lasers require control of irradiance distribution: round or square-shaped flat-top or super-Gaussian irradiance profiles are optimum for amplification in MOPA lasers and for thermal load management while pumping of crystals of solid-state ultra-short pulse lasers to control heat and minimize its impact on the laser power and beam quality while maximizing overall laser efficiency, variable profiles are also important in irradiating of photocathode of Free Electron lasers (FEL). It is suggested to solve the task of irradiance re-distribution using field mapping refractive beam shapers like piShaper. The operational principle of these devices presumes transformation of laser beam intensity from Gaussian to flat-top one with high flatness of output wavefront, saving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field, negligible residual wave aberration, and achromatic design provides capability to work with ultra-short pulse lasers having broad spectrum. Using the same piShaper device it is possible to realize beams with flat-top, inverse Gauss or super Gauss irradiance distribution by simple variation of input beam diameter, and the beam shape can be round or square with soft edges. This paper will describe some design basics of refractive beam shapers of the field mapping type and optical layouts of their applying in optical systems of high-power lasers. Examples of real implementations and experimental results will be presented as well.

Selective laser vaporization of polypropylene sutures and mesh

Science.gov (United States)

Burks, David; Rosenbury, Sarah B.; Kennelly, Michael J.; Fried, Nathaniel M.

2012-02-01

Complications from polypropylene mesh after surgery for female stress urinary incontinence (SUI) may require tedious surgical revision and removal of mesh materials with risk of damage to healthy adjacent tissue. This study explores selective laser vaporization of polypropylene suture/mesh materials commonly used in SUI. A compact, 7 Watt, 647-nm, red diode laser was operated with a radiant exposure of 81 J/cm2, pulse duration of 100 ms, and 1.0-mm-diameter laser spot. The 647-nm wavelength was selected because its absorption by water, hemoglobin, and other major tissue chromophores is low, while polypropylene absorption is high. Laser vaporization of ~200-μm-diameter polypropylene suture/mesh strands, in contact with fresh urinary tissue samples, ex vivo, was performed. Non-contact temperature mapping of the suture/mesh samples with a thermal camera was also conducted. Photoselective vaporization of polypropylene suture and mesh using a single laser pulse was achieved with peak temperatures of 180 and 232 °C, respectively. In control (safety) studies, direct laser irradiation of tissue alone resulted in only a 1 °C temperature increase. Selective laser vaporization of polypropylene suture/mesh materials is feasible without significant thermal damage to tissue. This technique may be useful for SUI procedures requiring surgical revision.

Technology Assessment of Laser-Assisted Materials Processing in Space

Science.gov (United States)

Nagarathnam, Karthik; Taminger, Karen M. B.

2001-01-01

Lasers are useful for performing operations such as joining, machining, built-up freeform fabrication, shock processing, and surface treatments. These attributes are attractive for the supportability of longer-term missions in space due to the multi-functionality of a single tool and the variety of materials that can be processed. However, current laser technology also has drawbacks for space-based applications, specifically size, power efficiency, lack of robustness, and problems processing highly reflective materials. A review of recent laser developments will be used to show how these issues may be reduced and indicate where further improvement is necessary to realize a laser-based materials processing capability in space. The broad utility of laser beams in synthesizing various classes of engineering materials will be illustrated using state-of-the art processing maps for select lightweight alloys typically found on spacecraft. With the advent of recent breakthroughs in diode-pumped solid-state lasers and fiber optic technologies, the potential to perform multiple processing techniques is increasing significantly. Lasers with suitable wavelengths and beam properties have tremendous potential for supporting future space missions to the moon, Mars and beyond.

Do rivers really obey power-laws? Using continuous high resolution measurements to define bankfull channel and evaluate downstream hydraulic-scaling over large changes in drainage area

Science.gov (United States)

Scher, C.; Tennant, C.; Larsen, L.; Bellugi, D. G.

2016-12-01

Advances in remote-sensing technology allow for cost-effective, accurate, high-resolution mapping of river-channel topography and shallow aquatic bathymetry over large spatial scales. A combination of near-infrared and green spectra airborne laser swath mapping was used to map river channel bathymetry and watershed geometry over 90+ river-kilometers (75-1175 km2) of the Greys River in Wyoming. The day of flight wetted channel was identified from green LiDAR returns, and more than 1800 valley-bottom cross-sections were extracted at regular 50-m intervals. The bankfull channel geometry was identified using a "watershed-based" algorithm that incrementally filled local minima to a "spill" point, thereby constraining areas of local convergence and delineating all the potential channels along the cross-section for each distinct "spill stage." Multiple potential channels in alluvial floodplains and lack of clearly defined channel banks in bedrock reaches challenge identification of the bankfull channel based on topology alone. Here we combine a variety of topological measures, geometrical considerations, and stage levels to define a stage-dependent bankfull channel geometry, and compare the results with day of flight wetted channel data. Initial results suggest that channel hydraulic geometry and basin hydrology power-law scaling may not accurately capture downstream channel adjustments for rivers draining complex mountain topography.

Breaking and Moving Hotspots in a Large Grain Nb Cavity with a Laser Beam

International Nuclear Information System (INIS)

Ciovati, G.; Cheng, G.; Flood, R. J.; Jordan, K.; Kneisel, P.; Morrone, M. L.; Turlington, L.; Wilson, K. M.; Zhang, S.; Anlage, S. M.; Gurevich, A. V.; Nemes, G.; Baldwin, C.

2011-01-01

Magnetic vortices pinned near the inner surface of SRF Nb cavities are a possible source of RF hotspots, frequently observed by temperature mapping of the cavities outer surface at RF surface magnetic fields of about 100 mT. Theoretically, we expect that the thermal gradient provided by a 10 W green laser shining on the inner cavity surface at the RF hotspot locations can move pinned vortices to different pinning locations. The experimental apparatus to send the beam onto the inner surface of a photoinjector-type large-grain Nb cavity is described. Preliminary results on the changes in thermal maps observed after applying the laser heating are also reported

Effect of deposition temperature on electron-beam evaporated polycrystalline silicon thin-film and crystallized by diode laser

Energy Technology Data Exchange (ETDEWEB)

Yun, J., E-mail: j.yun@unsw.edu.au; Varalmov, S.; Huang, J.; Green, M. A. [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales 2052 (Australia); Kim, K. [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales 2052 (Australia); Suntech R and D Australia, Botany, New South Wales 2019 (Australia)

2014-06-16

The effects of the deposition temperature on the microstructure, crystallographic orientation, and electrical properties of a 10-μm thick evaporated Si thin-film deposited on glass and crystallized using a diode laser, are investigated. The crystallization of the Si thin-film is initiated at a deposition temperature between 450 and 550 °C, and the predominant (110) orientation in the normal direction is found. Pole figure maps confirm that all films have a fiber texture and that it becomes stronger with increasing deposition temperature. Diode laser crystallization is performed, resulting in the formation of lateral grains along the laser scan direction. The laser power required to form lateral grains is higher in case of films deposited below 450 °C for all scan speeds. Pole figure maps show 75% occupancies of the (110) orientation in the normal direction when the laser crystallized film is deposited above 550 °C. A higher density of grain boundaries is obtained when the laser crystallized film is deposited below 450 °C, which limits the solar cell performance by n = 2 recombination, and a performance degradation is expected due to severe shunting.

Seep Detection using E/V Nautilus Integrated Seafloor Mapping and Remotely Operated Vehicles on the United States West Coast

Science.gov (United States)

Gee, L. J.; Raineault, N.; Kane, R.; Saunders, M.; Heffron, E.; Embley, R. W.; Merle, S. G.

2017-12-01

Exploration Vessel (E/V) Nautilus has been mapping the seafloor off the west coast of the United States, from Washington to California, for the past three years with a Kongsberg EM302 multibeam sonar. This system simultaneously collects bathymetry, seafloor and water column backscatter data, allowing an integrated approach to mapping to more completely characterize a region, and has identified over 1,000 seafloor seeps. Hydrographic multibeam sonars like the EM302 were designed for mapping the bathymetry. It is only in the last decade that major mapping projects included an integrated approach that utilizes the seabed and water column backscatter information in addition to the bathymetry. Nautilus mapping in the Eastern Pacific over the past three years has included a number of seep-specific expeditions, and utilized and adapted the preliminary mapping guidelines that have emerged from research. The likelihood of seep detection is affected by many factors: the environment: seabed geomorphology, surficial sediment, seep location/depth, regional oceanography and biology, the nature of the seeps themselves: size variation, varying flux, depth, and transience, the detection system: design of hydrographic multibeam sonars limits use for water column detection, the platform: variations in the vessel and operations such as noise, speed, and swath overlap. Nautilus integrated seafloor mapping provided multiple indicators of seep locations, but it remains difficult to assess the probability of seep detection. Even when seeps were detected, they have not always been located during ROV dives. However, the presence of associated features (methane hydrate and bacterial mats) serve as evidence of potential seep activity and reinforce the transient nature of the seeps. Not detecting a seep in the water column data does not necessarily indicate that there is not a seep at a given location, but with multiple passes over an area and by the use of other contextual data, an area may

Detection of laser damage by Raman microscopy

International Nuclear Information System (INIS)

Fauchet, P.M.; Campbell, I.H.; Adar, F.

1988-01-01

The authors demonstrate that Raman miroscopy is a sensitive and quantitative tool to detect and characterize laser-induced damage in solids. After damage is induced with single or multiple high power laser pulses, a Raman microprobe maps the surface of the sample with one micron spatial resolution. By performing accurate measurements of the Stokes line, the authors have been able to measure stress, strain and crystallinity in various samples which had been exposed to high intensity pulses. These results are compared to those obtained using conventional tools such as Nomarski microscopy. Major advantages of Raman microscopy include sensitivity to subtle structural modifications and the fact that it gives quantitative measurements

Snow and Ice Products from the Moderate Resolution Imaging Spectroradiometer

Science.gov (United States)

Hall, Dorothy K.; Salomonson, Vincent V.; Riggs, George A.; Klein, Andrew G.

2003-01-01

Snow and sea ice products, derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument, flown on the Terra and Aqua satellites, are or will be available through the National Snow and Ice Data Center Distributed Active Archive Center (DAAC). The algorithms that produce the products are automated, thus providing a consistent global data set that is suitable for climate studies. The suite of MODIS snow products begins with a 500-m resolution, 2330-km swath snow-cover map that is then projected onto a sinusoidal grid to produce daily and 8-day composite tile products. The sequence proceeds to daily and 8-day composite climate-modeling grid (CMG) products at 0.05 resolution. A daily snow albedo product will be available in early 2003 as a beta test product. The sequence of sea ice products begins with a swath product at 1-km resolution that provides sea ice extent and ice-surface temperature (IST). The sea ice swath products are then mapped onto the Lambert azimuthal equal area or EASE-Grid projection to create a daily and 8-day composite sea ice tile product, also at 1 -km resolution. Climate-Modeling Grid (CMG) sea ice products in the EASE-Grid projection at 4-km resolution are planned for early 2003.

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.

Printed organic smart devices characterized by ultra-short laser pulses

DEFF Research Database (Denmark)

Pastorelli, Francesco

Resume: In this study, we demonstrate that nonlinear optical microscopy is a promising technique to characterize organic printed electronics. Using ultrashort laser pulses we stimulate two-photon absorption in a roll coated polymer semiconductor and map the resulting two-photon induced...

Visual SLAM Using Variance Grid Maps

Science.gov (United States)

Howard, Andrew B.; Marks, Tim K.

2011-01-01

An algorithm denoted Gamma-SLAM performs further processing, in real time, of preprocessed digitized images acquired by a stereoscopic pair of electronic cameras aboard an off-road robotic ground vehicle to build accurate maps of the terrain and determine the location of the vehicle with respect to the maps. Part of the name of the algorithm reflects the fact that the process of building the maps and determining the location with respect to them is denoted simultaneous localization and mapping (SLAM). Most prior real-time SLAM algorithms have been limited in applicability to (1) systems equipped with scanning laser range finders as the primary sensors in (2) indoor environments (or relatively simply structured outdoor environments). The few prior vision-based SLAM algorithms have been feature-based and not suitable for real-time applications and, hence, not suitable for autonomous navigation on irregularly structured terrain. The Gamma-SLAM algorithm incorporates two key innovations: Visual odometry (in contradistinction to wheel odometry) is used to estimate the motion of the vehicle. An elevation variance map (in contradistinction to an occupancy or an elevation map) is used to represent the terrain. The Gamma-SLAM algorithm makes use of a Rao-Blackwellized particle filter (RBPF) from Bayesian estimation theory for maintaining a distribution over poses and maps. The core idea of the RBPF approach is that the SLAM problem can be factored into two parts: (1) finding the distribution over robot trajectories, and (2) finding the map conditioned on any given trajectory. The factorization involves the use of a particle filter in which each particle encodes both a possible trajectory and a map conditioned on that trajectory. The base estimate of the trajectory is derived from visual odometry, and the map conditioned on that trajectory is a Cartesian grid of elevation variances. In comparison with traditional occupancy or elevation grid maps, the grid elevation variance

Spectral and spatial resolving of photoelectric property of femtosecond laser drilled holes of GaSb(1-x)Bi(x).

Science.gov (United States)

Pan, C B; Zha, F X; Song, Y X; Shao, J; Dai, Y; Chen, X R; Ye, J Y; Wang, S M

2015-07-15

Femtosecond laser drilled holes of GaSbBi were characterized by the joint measurements of photoconductivity (PC) spectroscopy and laser-beam-induced current (LBIC) mapping. The excitation light in PC was focused down to 60 μm presenting the spectral information of local electronic property of individual holes. A redshift of energy band edge of about 6-8 meV was observed by the PC measurement when the excitation light irradiated on the laser drilled holes. The spatial resolving of photoelectric property was achieved by the LBIC mapping which shows "pseudo-holes" with much larger dimensions than the geometric sizes of the holes. The reduced LBIC current with the pseudo-holes is associated with the redshift effect indicating that the electronic property of the rim areas of the holes is modified by the femtosecond laser drilling.

Impact of an extended source in laser ablation using pulsed digital holographic interferometry and modelling

Energy Technology Data Exchange (ETDEWEB)

Amer, E., E-mail: eynas.amer@ltu.se [Lulea University of Technology, Department of Applied Physics and Mechanical Engineering, SE-971 87 Lulea (Sweden); Gren, P.; Kaplan, A.F.H.; Sjoedahl, M. [Lulea University of Technology, Department of Applied Physics and Mechanical Engineering, SE-971 87 Lulea (Sweden)

2009-08-15

Pulsed digital holographic interferometry has been used to study the effect of the laser spot diameter on the shock wave generated in the ablation process of an Nd:YAG laser pulse on a Zn target under atmospheric pressure. For different laser spot diameters and time delays, the propagation of the expanding vapour and of the shock wave were recorded by intensity maps calculated using the recorded digital holograms. From the latter, the phase maps, the refractive index and the density field can be derived. A model was developed that approaches the density distribution, in particular the ellipsoidal expansion characteristics. The induced shock wave has an ellipsoid shape that approaches a sphere for decreasing spot diameter. The ellipsoidal shock waves have almost the same centre offset towards the laser beam and the same aspect ratio for different time steps. The model facilitates the derivation of the particle velocity field. The method provides valuable quantitative results that are discussed, in particular in comparison with the simpler point source explosion theory.

Evidences of intraplate deformation in the West Madeira Abyssal Plain (eastern North Atlantic) from seismic reflection and multibeam swath bathymetry data

Science.gov (United States)

Roque, C.; Simões, M.; Lourenço, N.; Pinto de Abreu, M.

2009-04-01

The West Madeira Abyssal Plain is located in the eastern North Atlantic off Madeira Islands, forming part of the Canary Basin and reaching a mean water depth of 5300 m. This region is also located within Africa plate at about 500 km southwards from the Açores-Gibraltar plate boundary, and for that reason lacks seismic activity. Although this region being located in an intraplate setting, the presence of faulted sediments was reported in several works published during the eighties of last century following a study conducted in late 1970s to evaluate the feasibility of disposal of high-level radioactive wastes in the ocean. According these works, the Madeira Abyssal Plain sediments are cut by many normal growth faults and this deformation is a result of compaction and dewatering of the sediments. Evidences of tectonic deformation of oceanic sediments in intraplate settings are uncommon, but folded sediments and reverse faults extending into the basement, were recognized in the equatorial Indian Ocean and in the West African continental margin. Recently, during 2006 multi-channel seismic reflection and multibeam swath bathymetry surveys were carried out in the West Madeira Abyssal Plain by EMEPC in order to prepare the Portuguese proposal for the extension of the continental shelf. The seismic lines were acquired onboard R/V Akademik Shatskiy using a source of 5720 cu in bolt gun array, cable length of 7950 m and shot interval of 50.00 m. The multibeam swath bathymetry was acquired onboard NRP Gago Coutinho, and allowed a high resolution mapping of the main geomorphological features. The multichannel seismic lines, oriented WNW-ESE, image the Madeira island lower slope located at about 4000 m water depth and the almost flat abyssal plain at about 5300 m water depth. These seismic lines show a thick sedimentary succession that reaches a maximum thickness of about 1.5 sec twt in the deepest parts of the West Madeira Abyssal Plain, overlying an irregular diffractive

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

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.

Synchronous characterization of semiconductor microcavity laser beam.

Science.gov (United States)

Wang, T; Lippi, G L

2015-06-01

We report on a high-resolution double-channel imaging method used to synchronously map the intensity- and optical-frequency-distribution of a laser beam in the plane orthogonal to the propagation direction. The synchronous measurement allows us to show that the laser frequency is an inhomogeneous distribution below threshold, but that it becomes homogeneous across the fundamental Gaussian mode above threshold. The beam's tails deviations from the Gaussian shape, however, are accompanied by sizeable fluctuations in the laser wavelength, possibly deriving from manufacturing details and from the influence of spontaneous emission in the very low intensity wings. In addition to the synchronous spatial characterization, a temporal analysis at any given point in the beam cross section is carried out. Using this method, the beam homogeneity and spatial shape, energy density, energy center, and the defects-related spectrum can also be extracted from these high-resolution pictures.

Calculation of solidification microstructure maps for the system Al-Fe-Si

International Nuclear Information System (INIS)

Gilgien, P.

1996-01-01

Computer programs have been developed in order to calculate solidification microstructure maps for binary and ternary alloys. These programs are based on recent analytical models for the constrained growth of dendrites and eutectics. Due to the importance of phase diagrams data, programs for the calculation of growth kinetics are coupled with ThermoCalc, a commercial software for phase diagram calculations. These programs have been used to calculate a solidification microstructure map for the Al-Fe system from 0 to 4 at%Fe. Comparison of the calculated results with an experimental solidification microstructure map from the literature shows that all microstructure transitions were predicted. Nevertheless there remain significant discrepancies between some calculated and experimental transition velocities. The programs were also used to calculate solidification microstructure maps in the Al-rich corner of the Al-Fe-Si system (0 to 8 at% Fe and 0 to 8 at% Si). In this case also, calculated results were in satisfactory agreement with experimental solidification microstructure maps, although the comparison was only partial since experimental ternary microstructure maps are less complete than for the binary system, and because the available thermodynamic database does not, as yet, include metastable phases. Laser surface remelting experiments were carried out on an Al-4 at% Fe alloy in order to link results from the literature, obtained at high solidification rates by laser surface remelting and at low solidification rates by Bridman experiments. Finally, Bridman experiments were carried out with an Al-2.63 wt% Fe alloy in order to determine the critical velocity at which a planar Al-Al 13 Fe 4 eutectic front is destabilised in a cellular eutectic by a small amount of Si. The critical solidification velocity thus obtained was in agreement with a criterion of constitutional undercooling. (author) figs., tabs., refs

The OSIRIS-REx Laser Altimeter (OLA) Investigation and Instrument

Science.gov (United States)

Daly, M. G.; Barnouin, O. S.; Dickinson, C.; Seabrook, J.; Johnson, C. L.; Cunningham, G.; Haltigin, T.; Gaudreau, D.; Brunet, C.; Aslam, I.; Taylor, A.; Bierhaus, E. B.; Boynton, W.; Nolan, M.; Lauretta, D. S.

2017-10-01

The Canadian Space Agency (CSA) has contributed to the Origins Spectral Interpretation Resource Identification Security-Regolith Explorer (OSIRIS-REx) spacecraft the OSIRIS-REx Laser Altimeter (OLA). The OSIRIS-REx mission will sample asteroid 101955 Bennu, the first B-type asteroid to be visited by a spacecraft. Bennu is thought to be primitive, carbonaceous, and spectrally most closely related to CI and/or CM meteorites. As a scanning laser altimeter, the OLA instrument will measure the range between the OSIRIS-REx spacecraft and the surface of Bennu to produce digital terrain maps of unprecedented spatial scales for a planetary mission. The digital terrain maps produced will measure ˜7 cm per pixel globally, and ˜3 cm per pixel at specific sample sites. In addition, OLA data will be used to constrain and refine the spacecraft trajectories. Global maps and highly accurate spacecraft trajectory estimates are critical to infer the internal structure of the asteroid. The global and regional maps also are key to gain new insights into the surface processes acting across Bennu, which inform the selection of the OSIRIS-REx sample site. These, in turn, are essential for understanding the provenance of the regolith sample collected by the OSIRIS-REx spacecraft. The OLA data also are important for quantifying any hazards near the selected OSIRIS-REx sample site and for evaluating the range of tilts at the sampling site for comparison against the capabilities of the sample acquisition device.

Indoor Map Acquisition System Using Global Scan Matching Method and Laser Range Scan Data

Science.gov (United States)

Hisanaga, Satoshi; Kase, Takaaki

Simultaneous localization and mapping (SLAM) is the latest technique for constructing indoor maps. In indoor environment, a localization method using the features of the walls as landmarks has been studied in the past. The past study has a drawback. It cannot localize in spaces surrounded by featureless walls or walls on which similar features are repeated. To overcome this drawback, we developed an accuracy localization method that ignores the features of the walls. We noted the fact that the walls in a building are aligned along only two orthogonal directions. By considering a specific wall to be a reference wall, the location of a robot was expressed by using the distance between the robot and the reference wall. We developed the robot in order to evaluate the mapping accuracy of our method and carried out an experiment to map a corridor (40m long) that contained featureless parts. The map obtained had a margin of error of less than 2%.

Conversion efficiency of implanted ions by confocal micro-luminescence mapping

International Nuclear Information System (INIS)

Deshko, Y.; Huang, Mengbing; Gorokhovsky, A.A.

2013-01-01

We report on the further development of the statistical approach to determine the conversion efficiency of implanted ions into emitting centers and present the measurement method based on the confocal micro-luminescence mapping. It involves the micro-luminescence mapping with a narrow-open confocal aperture, followed by the statistical analysis of the photoluminescence signal from an ensemble of emitting centers. The confocal mapping method has two important advantages compared to the recently discussed aperture-free method (J. Lumin. 131 (2011) 489): it is less sensitive to errors in the laser spot size and has a well defined useful area. The confocal mapping has been applied to the Xe center in diamond. The conversion efficiency has been found to be about 0.28, which is in good agreement with the results of the aperture-free method. - Highlights: ► Conversion efficiency of implanted ions into emitting centers – statistical approach. ► Micro-luminescence mapping with open and narrow confocal aperture – comparison. ► Advantages of the confocal micro-luminescence mapping. ► Confocal micro-luminescence mapping has been applied to the Xe center in diamond. ► The conversion efficiency has been found to be about 0.28.

Development of a 2D laser ablation inductively coupled plasma mass spectrometry mapping procedure for mercury in maize (Zea mays L.) root cross-sections

Energy Technology Data Exchange (ETDEWEB)

Debeljak, Marta [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna Pot 111, SI-1000 Ljubljana (Slovenia); Elteren, Johannes T. van, E-mail: elteren@ki.si [Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Vogel-Mikuš, Katarina [Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna Pot 111, SI-1000 Ljubljana (Slovenia)

2013-07-17

Graphical abstract: -- Highlights: •LA-ICP-MS mapping to study the distribution of Hg in plant root cross-sections. •Sorption of LA-generated Hg vapour leads to serious memory effects. •Spot analysis with a delay time of 10 s in between spots alleviates memory effects. •Ablation straight through the sample simplifies calibration. •Hg{sup 2+} does not cross the endodermal root barrier of maize plants. -- Abstract: A LA-ICP-MS method based on a 213 nm Nd:YAG laser and a quadrupole ICP-MS has been developed for mapping of mercury in root cross-sections of maize (Zea mays L.) to investigate the mechanism of mercury uptake from soil and its potential translocation to the edible parts. Conventional rastering was found to be unusable due to sorption of mercury onto the internal parts of the LA device, giving rising to memory effects resulting in serious loss of resolution and inaccurate quantification. Spot analysis on a virtual grid on the surface of the root sections using washout times of 10 s in between spots greatly alleviated problems related to these memory effects. By ablating straight through the root sections on a poly(methyl methacrylate) support the calibration process was simplified as internal standardization and matrix-matching could be circumvented. Mercury-spiked freeze-drying embedding medium, sectioned similarly to the root sections, was used for the preparation of the standards. Standards and root sections were subjected to spot analysis using the following operational parameters: beam diameter, 15 μm; laser fluence, 2.5 J cm{sup −2}; repetition rate, 20 Hz; dwell time, 1 s; acquisition time, 0.1 s. The mercury peaks for standards and roots sections could be consistently integrated for quantification and construction of the 2D mercury maps for the root sections. This approach was successfully used to investigate the mercury distribution in root sections of maize grown in soil spiked to a level of 50 mg kg{sup −1} DW HgCl{sub 2}. It was

Development of a 2D laser ablation inductively coupled plasma mass spectrometry mapping procedure for mercury in maize (Zea mays L.) root cross-sections

International Nuclear Information System (INIS)

Debeljak, Marta; Elteren, Johannes T. van; Vogel-Mikuš, Katarina

2013-01-01

Graphical abstract: -- Highlights: •LA-ICP-MS mapping to study the distribution of Hg in plant root cross-sections. •Sorption of LA-generated Hg vapour leads to serious memory effects. •Spot analysis with a delay time of 10 s in between spots alleviates memory effects. •Ablation straight through the sample simplifies calibration. •Hg 2+ does not cross the endodermal root barrier of maize plants. -- Abstract: A LA-ICP-MS method based on a 213 nm Nd:YAG laser and a quadrupole ICP-MS has been developed for mapping of mercury in root cross-sections of maize (Zea mays L.) to investigate the mechanism of mercury uptake from soil and its potential translocation to the edible parts. Conventional rastering was found to be unusable due to sorption of mercury onto the internal parts of the LA device, giving rising to memory effects resulting in serious loss of resolution and inaccurate quantification. Spot analysis on a virtual grid on the surface of the root sections using washout times of 10 s in between spots greatly alleviated problems related to these memory effects. By ablating straight through the root sections on a poly(methyl methacrylate) support the calibration process was simplified as internal standardization and matrix-matching could be circumvented. Mercury-spiked freeze-drying embedding medium, sectioned similarly to the root sections, was used for the preparation of the standards. Standards and root sections were subjected to spot analysis using the following operational parameters: beam diameter, 15 μm; laser fluence, 2.5 J cm −2 ; repetition rate, 20 Hz; dwell time, 1 s; acquisition time, 0.1 s. The mercury peaks for standards and roots sections could be consistently integrated for quantification and construction of the 2D mercury maps for the root sections. This approach was successfully used to investigate the mercury distribution in root sections of maize grown in soil spiked to a level of 50 mg kg −1 DW HgCl 2 . It was found that at given

Hight Energy Fiber Laser Based Lidar Transmitter for Topographic Mapping, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This SBIR will develop core Yb laser technology that is higher than 50% optical to optical efficient with pulse energies up to 300uJ/pulse in the all fiber version...

Application of 3D laser scanning technology in historical building preservation: a case study of a Chinese temple

Science.gov (United States)

Chang, Yu Min; Lu, Nien Hua; Wu, Tsung Chiang

2005-06-01

This study applies 3D Laser scanning technology to develop a high-precision measuring system for digital survey of historical building. It outperformed other methods in obtaining abundant high-precision measuring points and computing data instantly. In this study, the Pei-tien Temple, a Chinese Taoism temple in southern Taiwan famous for its highly intricate architecture and more than 300-year history, was adopted as the target to proof the high accuracy and efficiency of this system. By using French made MENSI GS-100 Laser Scanner, numerous measuring points were precisely plotted to present the plane map, vertical map and 3D map of the property. Accuracies of 0.1-1 mm in the digital data have consistently been achieved for the historical heritage measurement.

Multi-Beam Surface Lidar for Lunar and Planetary Mapping

Science.gov (United States)

Bufton, Jack L.; Garvin, James B.

1998-01-01

Surface lidar techniques are now being demonstrated in low Earth orbit with a single beam of pulsed laser radiation at 1064 nm that profiles the vertical structure of Earth surface landforms along the nadir track of a spacecraft. In addition, a profiling laser altimeter, called MOLA, is operating in elliptical Martian orbit and returning surface topography data. These instruments form the basis for suggesting an improved lidar instrument that employs multiple beams for extension of sensor capabilities toward the goal of true, 3-dimensional mapping of the Moon or other similar planetary surfaces. In general the lidar waveform acquired with digitization of a laser echo can be used for laser distance measurement (i.e. range-to-the-surface) by time-of-flight measurement and for surface slope and shape measurements by examining the detailed lidar waveform. This is particularly effective when the intended target is the lunar surface or another planetary body free of any atmosphere. The width of the distorted return pulse is a first order measure of the surface incidence angle, a combination of surface slope and laser beam pointing. Assuming an independent and absolute (with respect to inertial space) measurement of laser beam pointing on the spacecraft, it is possible to derive a surface slope with-respect-to the mean planetary surface or its equipotential gravity surface. Higher-order laser pulse distortions can be interpreted in terms of the vertical relief of the surface or reflectivity variations within the area of the laser beam footprint on the surface.

Dynamic Mapping of Rice Growth Parameters Using HJ-1 CCD Time Series Data

Directory of Open Access Journals (Sweden)

Jing Wang

2016-11-01

Full Text Available The high temporal resolution (4-day charge-coupled device (CCD cameras onboard small environment and disaster monitoring and forecasting satellites (HJ-1A/B with 30 m spatial resolution and large swath (700 km have substantially increased the availability of regional clear sky optical remote sensing data. For the application of dynamic mapping of rice growth parameters, leaf area index (LAI and aboveground biomass (AGB were considered as plant growth indicators. The HJ-1 CCD-derived vegetation indices (VIs showed robust relationships with rice growth parameters. Cumulative VIs showed strong performance for the estimation of total dry AGB. The cross-validation coefficient of determination ( R C V 2 was increased by using two machine learning methods, i.e., a back propagation neural network (BPNN and a support vector machine (SVM compared with traditional regression equations of LAI retrieval. The LAI inversion accuracy was further improved by dividing the rice growth period into before and after heading stages. This study demonstrated that continuous rice growth monitoring over time and space at field level can be implemented effectively with HJ-1 CCD 10-day composite data using a combination of proper VIs and regression models.

Wide-area mapping of resting state hemodynamic correlations at microvascular resolution with multi-contrast optical imaging (Conference Presentation)

Science.gov (United States)

Senarathna, Janaka; Hadjiabadi, Darian; Gil, Stacy; Thakor, Nitish V.; Pathak, Arvind P.

2017-02-01

Different brain regions exhibit complex information processing even at rest. Therefore, assessing temporal correlations between regions permits task-free visualization of their `resting state connectivity'. Although functional MRI (fMRI) is widely used for mapping resting state connectivity in the human brain, it is not well suited for `microvascular scale' imaging in rodents because of its limited spatial resolution. Moreover, co-registered cerebral blood flow (CBF) and total hemoglobin (HbT) data are often unavailable in conventional fMRI experiments. Therefore, we built a customized system that combines laser speckle contrast imaging (LSCI), intrinsic optical signal (IOS) imaging and fluorescence imaging (FI) to generate multi-contrast functional connectivity maps at a spatial resolution of 10 μm. This system comprised of three illumination sources: a 632 nm HeNe laser (for LSCI), a 570 nm ± 5 nm filtered white light source (for IOS), and a 473 nm blue laser (for FI), as well as a sensitive CCD camera operating at 10 frames per second for image acquisition. The acquired data enabled visualization of changes in resting state neurophysiology at microvascular spatial scales. Moreover, concurrent mapping of CBF and HbT-based temporal correlations enabled in vivo mapping of how resting brain regions were linked in terms of their hemodynamics. Additionally, we complemented this approach by exploiting the transit times of a fluorescent tracer (Dextran-FITC) to distinguish arterial from venous perfusion. Overall, we demonstrated the feasibility of wide area mapping of resting state connectivity at microvascular resolution and created a new toolbox for interrogating neurovascular function.

Optical Performance Measurements of the BELA EQM and FM Transmitter Laser during AIV

Science.gov (United States)

Althaus, C.; Michaelis, H.; Lingenauber, K.; Behnke, T.; Togno, S. d.; Kallenbach, R.; Wickhusen, K.; Althaus, C.

2014-04-01

The BepiColombo Laser Altimeter (BELA) onboard the Mercury Planetary Orbiter is Europe's first built Laser Altimeter for a planetary mission. Its main objectives are global mapping of Mercury's topography as well as measuring its tidal deformations to learn about the internal structure of this small terrestrial planet [1]. Crucial part of the instrument for this task is the transmitter laser. It must withstand all mission phases till operation in orbit and work within tight parameter margins. To ensure this a dedicated verification program has been performed at DLR Institute for Planetary Research Berlin which is described in the present paper.

Output of CT images and treatment planning data to a laser printer

International Nuclear Information System (INIS)

Kleinschmidt, C.; Gfirtner, H.; Goetzfried, M.

1992-01-01

We introduce a program for the digital output of CT images with overlaid isodose maps to a laser printer. The high quality prints permit the additional output of treatment planning data on the same sheet. (orig.) [de

Non-Topographic Space-Based Laser Remote Sensing

Science.gov (United States)

Yu, Anthony W.; Abshire, James B.; Riris, Haris; Purucker, Michael; Janches, Diego; Getty, Stephanie; Krainak, Michael A.; Stephen, Mark A.; Chen, Jeffrey R.; Li, Steve X.;

UV laser interaction with a fluorescent dye solution studied using pulsed digital holography.

Science.gov (United States)

Amer, Eynas; Gren, Per; Sjödahl, Mikael

2013-10-21

A frequency tripled Q-switched Nd-YAG laser (wavelength 355 nm, pulse duration 12 ns) has been used to pump Coumarin 153 dye solved in ethanol. Simultaneously, a frequency doubled pulse (532 nm) from the same laser is used to probe the solvent perpendicularly resulting in a gain through stimulated laser induced fluorescence (LIF) emission. The resulting gain of the probe beam is recorded using digital holography by blending it with a reference beam on the detector. Two digital holograms without and with the pump beam were recorded. Intensity maps were calculated from the recorded digital holograms and used to calculate the gain of the probe beam due to the stimulated LIF. In addition numerical data of the local temperature rise was calculated from the corresponding phase maps using Radon inversion. It was concluded that about 15% of the pump beam energy is transferred to the dye solution as heat while the rest is consumed in the radiative process. The results show that pulsed digital holography is a promising technique for quantitative study of fluorescent species.

Vendor-based laser damage metrology equipment supporting the National Ignition Facility

International Nuclear Information System (INIS)

Campbell, J. H; Jennings, R. T.; Kimmons, J. F.; Kozlowski, M. R.; Mouser, R. P.; Schwatz, S.; Stolz, C. J.; Weinzapfel, C. L.

1998-01-01

A sizable laser damage metrology effort is required as part of optics production and installation for the 192 beam National Ignition Facility (NIF) laser. The large quantities, high damage thresholds, and large apertures of polished and coated optics necessitates vendor-based metrology equipment to assure component quality during production. This equipment must be optimized to provide the required information as rapidly as possible with limited operator experience. The damage metrology tools include: (1) platinum inclusion damage test systems for laser amplifier slabs, (2) laser conditioning stations for mirrors and polarizers, and (3) mapping and damage testing stations for UV transmissive optics. Each system includes a commercial Nd:YAG laser, a translation stage for the optics, and diagnostics to evaluate damage. The scanning parameters, optical layout, and diagnostics vary with the test fluences required and the damage morphologies expected. This paper describes the technical objectives and milestones involved in fulfilling these metrology requirements

Research of cartographer laser SLAM algorithm

Science.gov (United States)

Xu, Bo; Liu, Zhengjun; Fu, Yiran; Zhang, Changsai

2017-11-01

As the indoor is a relatively closed and small space, total station, GPS, close-range photogrammetry technology is difficult to achieve fast and accurate indoor three-dimensional space reconstruction task. LIDAR SLAM technology does not rely on the external environment a priori knowledge, only use their own portable lidar, IMU, odometer and other sensors to establish an independent environment map, a good solution to this problem. This paper analyzes the Google Cartographer laser SLAM algorithm from the point cloud matching and closed loop detection. Finally, the algorithm is presented in the 3D visualization tool RViz from the data acquisition and processing to create the environment map, complete the SLAM technology and realize the process of indoor threedimensional space reconstruction

A net normal dispersion all-fiber laser using a hybrid mode-locking mechanism

International Nuclear Information System (INIS)

Xu, Bo; Martinez, Amos; Yamashita, Shinji; Set, Sze Yun; Goh, Chee Seong

2014-01-01

We propose and demonstrate an all-fiber, dispersion-mapped, erbium-doped fiber laser with net normal dispersion generating dissipative solitons. The laser is mode-locked by a hybrid mode-locking mechanism consisting of a nonlinear amplifying loop mirror and a carbon nanotube saturable absorber. We achieve self-starting, mode-locked operation generating 2.75 nJ pulses at a fundamental repetition rate of 10.22 MHz with remarkable long term stability. (letter)

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

Harmonic mode-locking and sub-round-trip time nonlinear dynamics of electro-optically controlled solid state laser

Science.gov (United States)

Gorbunkov, M. V.; Maslova, Yu Ya; Petukhov, V. A.; Semenov, M. A.; Shabalin, Yu V.; Tunkin, V. G.

2018-03-01

Harmonic mode-locking in a solid state laser due to optoelectronic control is studied numerically on the basis of two methods. The first one is detailed numeric simulation taking into account laser radiation fine time structure. It is shown that optimally chosen feedback delay leads to self-started mode-locking with generation of desired number of pulses in the laser cavity. The second method is based on discrete maps for short laser pulse energy. Both methods show that the application of combination of positive and negative feedback loops allows to reduce the period of regular nonlinear dynamics down to a fraction of a laser cavity round trip time.

Laser-scanning astrocyte mapping reveals increased glutamate-responsive domain size and disrupted maturation of glutamate uptake following neonatal cortical freeze-lesion

Directory of Open Access Journals (Sweden)

Mortiz eArmbruster

2014-09-01

Full Text Available Astrocytic uptake of glutamate shapes extracellular neurotransmitter dynamics, receptor activation, and synaptogenesis. During development, glutamate transport becomes more robust. How neonatal brain insult affects the functional maturation of glutamate transport remains unanswered. Neonatal brain insult can lead to developmental delays, cognitive losses, and epilepsy; the disruption of glutamate transport is known to cause changes in synaptogenesis, receptor activation, and seizure. Using the neonatal freeze-lesion (FL model, we have investigated how insult affects the maturation of astrocytic glutamate transport. As lesioning occurs on the day of birth, a time when astrocytes are still functionally immature, this model is ideal for identifying changes in astrocyte maturation following insult. Reactive astrocytosis, astrocyte proliferation, and in vitro hyperexcitability are known to occur in this model. To probe astrocyte glutamate transport with better spatial precision we have developed a novel technique, Laser Scanning Astrocyte Mapping (LSAM, which combines glutamate transport current (TC recording from astrocytes with laser scanning glutamate photolysis. LSAM allows us to identify the area from which a single astrocyte can transport glutamate and to quantify spatial heterogeneity in the rate of glutamate clearance kinetics within that domain. Using LSAM, we report that cortical astrocytes have an increased glutamate-responsive area following FL and that TCs have faster decay times in distal, as compared to proximal processes. Furthermore, the developmental shift from GLAST- to GLT-1-dominated clearance is disrupted following FL. These findings introduce a novel method to probe astrocyte glutamate uptake and show that neonatal cortical FL disrupts the functional maturation of cortical astrocytes.

Measurement and interpretation of laser accelerated protons at GSI

International Nuclear Information System (INIS)

Al-Omari, Husam

2014-01-01

This thesis is structured into 7 chapters: - Chapter 2 gives an overview of the ultrashort high intensity laser interaction with matter. The laser interaction with an induced plasma is described, starting from the kinematics of single electron motion, followed by collective electron effects and the ponderamotive motion in the laser focus and the plasma transparency for the laser beam. The three different mechanisms prepared to accelerate and propagate electrons through matter are discussed. The following indirect acceleration of protons is explained by the Target Normal Sheath Acceleration (TNSA) mechanism. Finally some possible applications of laser accelerated protons are explained briefly. - Chapter 3 deals with the modeling of geometry and field mapping of magnetic lens. Initial proton and electron distributions, fitted to PHELIX measured data are generated, a brief description of employed codes and used techniques in simulation is given, and the aberrations at the solenoid focal spot is studied. - Chapter 4 presents a simulation study for suggested corrections to optimize the proton beam as a later beam source. Two tools have been employed in these suggested corrections, an aperture placed at the solenoid focal spot as energy selection tool, and a scattering foil placed in the proton beam to smooth the radial energy beam profile correlation at the focal spot due to chromatic aberrations. Another suggested correction has been investigated, to optimize the beam radius at the focal spot by lens geometry controlling. - Chapter 5 presents a simulation study for the de-neutralization problem in TNSA caused by the fringing fields of pulsed magnetic solenoid and quadrupole. In this simulation, we followed an electrostatic model, where the evolution of both, self and mutual fields through the pulsed magnetic solenoid could be found, which is not the case in the quadrupole and only the growth of self fields could be found. The field mapping of magnetic elements is

Measurement and interpretation of laser accelerated protons at GSI

Energy Technology Data Exchange (ETDEWEB)

Al-Omari, Husam

2014-04-28

This thesis is structured into 7 chapters: - Chapter 2 gives an overview of the ultrashort high intensity laser interaction with matter. The laser interaction with an induced plasma is described, starting from the kinematics of single electron motion, followed by collective electron effects and the ponderamotive motion in the laser focus and the plasma transparency for the laser beam. The three different mechanisms prepared to accelerate and propagate electrons through matter are discussed. The following indirect acceleration of protons is explained by the Target Normal Sheath Acceleration (TNSA) mechanism. Finally some possible applications of laser accelerated protons are explained briefly. - Chapter 3 deals with the modeling of geometry and field mapping of magnetic lens. Initial proton and electron distributions, fitted to PHELIX measured data are generated, a brief description of employed codes and used techniques in simulation is given, and the aberrations at the solenoid focal spot is studied. - Chapter 4 presents a simulation study for suggested corrections to optimize the proton beam as a later beam source. Two tools have been employed in these suggested corrections, an aperture placed at the solenoid focal spot as energy selection tool, and a scattering foil placed in the proton beam to smooth the radial energy beam profile correlation at the focal spot due to chromatic aberrations. Another suggested correction has been investigated, to optimize the beam radius at the focal spot by lens geometry controlling. - Chapter 5 presents a simulation study for the de-neutralization problem in TNSA caused by the fringing fields of pulsed magnetic solenoid and quadrupole. In this simulation, we followed an electrostatic model, where the evolution of both, self and mutual fields through the pulsed magnetic solenoid could be found, which is not the case in the quadrupole and only the growth of self fields could be found. The field mapping of magnetic elements is

Erosion can't hide from laser scanner

International Nuclear Information System (INIS)

Konstant, D.A.

1991-01-01

Particles of topsoil blown by wind will bounce along the soil surface and finally escape a field, leaving it less able to support crops. Water will wash away valuable topsoil and nutrients. And how rough the soil surface is influences whether the soil will erode. Until now, soil scientists have had no suitable technique to measure soil roughness - or microtopography - on the small scale. ARS soil scientists Joe M. Bradford and Chi-hua Huang, of the National Soil Erosion Research Laboratory in West Lafayette, Indiana, have developed a portable scanner that can. It measures the tiny ridges left in the soil by tilling or clods of soil particles that clump together naturally. What does the scanner do? It measures soil elevation by shining a low-power laser beam onto the surface and detecting the position of the laser spot reflected from the soil with a 35-mm camera. In place of film, the scanner camera uses electronic circuitry somewhat similar to that in a video camera to transmit the spot's position to a small computer about 30,000 times a minute. The laser and camera are mounted on the frame of a motor-driven carriage. The computer controls the carriage movement. At the end of a scan, a microtopographic map is stored in the computer. Scientists can analyze it immediately and can compare it to previous maps to see whether erosion has occurred

Building extraction for 3D city modelling using airborne laser ...

African Journals Online (AJOL)

Light detection and ranging (LiDAR) technology has become a standard tool for three-dimensional mapping because it offers fast rate of data acquisition with unprecedented level of accuracy. This study presents an approach to accurately extract and model building in three-dimensional space from airborne laser scanning ...

Frequency mixing in boron carbide laser ablation plasmas

Science.gov (United States)

Oujja, M.; Benítez-Cañete, A.; Sanz, M.; Lopez-Quintas, I.; Martín, M.; de Nalda, R.; Castillejo, M.

2015-05-01

Nonlinear frequency mixing induced by a bichromatic field (1064 nm + 532 nm obtained from a Q-switched Nd:YAG laser) in a boron carbide (B4C) plasma generated through laser ablation under vacuum is explored. A UV beam at the frequency of the fourth harmonic of the fundamental frequency (266 nm) was generated. The dependence of the efficiency of the process as function of the intensities of the driving lasers differs from the expected behavior for four-wave mixing, and point toward a six-wave mixing process. The frequency mixing process was strongly favored for parallel polarizations of the two driving beams. Through spatiotemporal mapping, the conditions for maximum efficiency were found for a significant delay from the ablation event (200 ns), when the medium is expected to be a low-ionized plasma. No late components of the harmonic signal were detected, indicating a largely atomized medium.

Elaboration of submicron structures on PEEK polymer by femtosecond laser

International Nuclear Information System (INIS)

Hammouti, S.; Beaugiraud, B.; Salvia, M.; Mauclair, C.; Pascale-Hamri, A.; Benayoun, S.; Valette, S.

2015-01-01

Highlights: • We compare PEEK polymer under two crystalline forms: semi-crystalline and amorphous. • We assess topographical modifications of surface morphologies after femtosecond laser irradiation. • At low laser energy regime, there is an influence of the crystallinity rate on topographical features of surface morphologies. • At high laser energy regime, the contribution of the crystallinity tends to disappear. - Abstract: In this work, laser parameters initiating the emergence of periodic structures, so-called ripples on poly (ether ether ketone) (PEEK) surfaces, are investigated. PEEK was used in its semi-crystalline and amorphous forms. Polymer surfaces were treated locally by performing a matrix of laser impacts to highlight the influence of the crystallinity in ultrashort laser interaction. Different surface morphologies or ripples were analyzed by atomic force microscopy and optical interferometry. A map of the presence of these different morphologies according to the laser fluence and the number of pulses was established. Analysis by optical interferometry was carried out and led to the calculations of ablation efficiency. Some significant differences were demonstrated between amorphous and semi-crystalline surfaces. This work revealed topographical information on the local behavior of the irradiated material. Finally, the crystallinity rate of polymer surface seems to be a determinant factor for the periodic nanostructured appearance

Elaboration of submicron structures on PEEK polymer by femtosecond laser

Energy Technology Data Exchange (ETDEWEB)

Hammouti, S., E-mail: sabrina.hammouti@ec-lyon.fr [LTDS, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); Beaugiraud, B.; Salvia, M. [LTDS, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); Mauclair, C. [LaHC, Université Jean Monnet, 18 rue du Professeur Benoît Lauras, 42000 Saint-Etienne (France); MANUTECH-USD, 20 rue du Professeur Benoît Lauras, 42000 Saint-Etienne (France); Pascale-Hamri, A. [MANUTECH-USD, 20 rue du Professeur Benoît Lauras, 42000 Saint-Etienne (France); Benayoun, S. [LTDS, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); Valette, S. [LTDS, Ecole Centrale de Lyon, 36 Avenue Guy de Collongue, 69134 Ecully (France); MANUTECH-USD, 20 rue du Professeur Benoît Lauras, 42000 Saint-Etienne (France)

2015-02-01

Highlights: • We compare PEEK polymer under two crystalline forms: semi-crystalline and amorphous. • We assess topographical modifications of surface morphologies after femtosecond laser irradiation. • At low laser energy regime, there is an influence of the crystallinity rate on topographical features of surface morphologies. • At high laser energy regime, the contribution of the crystallinity tends to disappear. - Abstract: In this work, laser parameters initiating the emergence of periodic structures, so-called ripples on poly (ether ether ketone) (PEEK) surfaces, are investigated. PEEK was used in its semi-crystalline and amorphous forms. Polymer surfaces were treated locally by performing a matrix of laser impacts to highlight the influence of the crystallinity in ultrashort laser interaction. Different surface morphologies or ripples were analyzed by atomic force microscopy and optical interferometry. A map of the presence of these different morphologies according to the laser fluence and the number of pulses was established. Analysis by optical interferometry was carried out and led to the calculations of ablation efficiency. Some significant differences were demonstrated between amorphous and semi-crystalline surfaces. This work revealed topographical information on the local behavior of the irradiated material. Finally, the crystallinity rate of polymer surface seems to be a determinant factor for the periodic nanostructured appearance.

Laser display system for multi-depth screen projection scenarios.

Science.gov (United States)

La Torre, J Pablo; Mayes, Nathan; Riza, Nabeel A

2017-11-10

Proposed is a laser projection display system that uses an electronically controlled variable focus lens (ECVFL) to achieve sharp and in-focus image projection over multi-distance three-dimensional (3D) conformal screens. The system also functions as an embedded distance sensor that enables 3D mapping of the multi-level screen platform before the desired laser scanned beam focused/defocused projected spot sizes are matched to the different localized screen distances on the 3D screen. Compared to conventional laser scanning and spatial light modulator (SLM) based projection systems, the proposed design offers in-focus non-distorted projection over a multi-distance screen zone with varying depths. An experimental projection system for a screen depth variation of 65 cm is demonstrated using a 633 nm laser beam, 3 KHz scan speed galvo-scanning mirrors, and a liquid-based ECVFL. As a basic demonstration, an in-house developed MATLAB based graphic user interface is deployed to work along with the laser projection display, enabling user inputs like text strings or predefined image projection. The user can specify projection screen distance, scanned laser linewidth, projected text font size, projected image dimensions, and laser scanning rate. Projected images are shown highlighting the 3D control capabilities of the display, including the production of a non-distorted image onto two-depths versus a distorted image via dominant prior-art projection methods.

Derivation of Ground Surface and Vegetation in a Coastal Florida Wetland with Airborne Laser Technology

Science.gov (United States)

Raabe, Ellen A.; Harris, Melanie S.; Shrestha, Ramesh L.; Carter, William E.

2008-01-01

The geomorphology and vegetation of marsh-dominated coastal lowlands were mapped from airborne laser data points collected on the Gulf Coast of Florida near Cedar Key. Surface models were developed using low- and high-point filters to separate ground-surface and vegetation-canopy intercepts. In a non-automated process, the landscape was partitioned into functional landscape units to manage the modeling of key landscape features in discrete processing steps. The final digital ground surface-elevation model offers a faithful representation of topographic relief beneath canopies of tidal marsh and coastal forest. Bare-earth models approximate field-surveyed heights by + 0.17 m in the open marsh and + 0.22 m under thick marsh or forest canopy. The laser-derived digital surface models effectively delineate surface features of relatively inaccessible coastal habitats with a geographic coverage and vertical detail previously unavailable. Coastal topographic details include tidal-creek tributaries, levees, modest topographic undulations in the intertidal zone, karst features, silviculture, and relict sand dunes under coastal-forest canopy. A combination of laser-derived ground-surface and canopy-height models and intensity values provided additional mapping capabilities to differentiate between tidal-marsh zones and forest types such as mesic flatwood, hydric hammock, and oak scrub. Additional derived products include fine-scale shoreline and topographic profiles. The derived products demonstrate the capability to identify areas of concern to resource managers and unique components of the coastal system from laser altimetry. Because the very nature of a wetland system presents difficulties for access and data collection, airborne coverage from remote sensors has become an accepted alternative for monitoring wetland regions. Data acquisition with airborne laser represents a viable option for mapping coastal topography and for evaluating habitats and coastal change on marsh

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.

Using focal mechanism solutions to correlate earthquakes with faults in the Lake Tahoe-Truckee area, California and Nevada, and to help design LiDAR surveys for active-fault reconnaissance

Science.gov (United States)

Cronin, V. S.; Lindsay, R. D.

2011-12-01

trace of both the Polaris fault and the Dog Valley fault system are within composite swaths defined by overlapping seismo-lineaments. Composite seismo-lineaments indicate that multiple historic earthquakes might be associated with a fault. This apparently successful correlation of earthquakes with faults in an area where geologic mapping is good suggests another use for SLAM in areas where fault mapping is incomplete, inadequate or made particularly difficult because of vegetative cover. If no previously mapped fault exists along a composite swath generated using well constrained focal mechanism solutions, the swath might be used to guide the design of a LiDAR survey in support of reconnaissance for the causative fault. The acquisition and geomorphic analysis of LiDAR data along a compound seismo-lineament swath might reveal geomorphic evidence of a previously unrecognized fault trace that is worthy of additional field study.

Dedicated Filter for Robust Occupancy Grid Mapping

Directory of Open Access Journals (Sweden)

KS Nagla

2015-03-01

Full Text Available Sensor based perception of the environment is an emerging area of the mobile robot research where sensors play a pivotal role. For autonomous mobile robots, the fundamental requirement is the convergent of the range information in to high level internal representation. Internal representation in the form of occupancy grid is commonly used in autonomous mobile robots due to its various advantages. There are several sensors such as vision sensor, laser rage finder, and ultrasonic and infrared sensors etc. play roles in mapping. However the sensor information failure, sensor inaccuracies, noise, and slow response are the major causes of an error in the mapping. To improve the reliability of the mobile robot mapping multisensory data fusion is considered as an optimal solution. This paper presents a novel architecture of sensor fusion frame work in which a dedicated filter (DF is proposed to increase the robustness of the occupancy grid for indoor environment. The technique has been experimentally verified for different indoor test environments. The proposed configuration shows improvement in the occupancy grid with the implementation of dedicated filters.

Photogrammetry and altimetry. Part A: Apollo 16 laser altimeter

Science.gov (United States)

Wollenhaupt, W. R.; Sjogren, W. L.

1972-01-01

The laser altimeter measures precise altitudes of the command and service module above the lunar surface and can function either with the metric (mapping) camera or independently. In the camera mode, the laser altimeter ranges at each exposure time, which varies between 20 and 28 sec (i.e., 30 to 43 km on the lunar surface). In the independent mode, the laser altimeter ranges every 20 sec. These altitude data and the spacecraft attitudes that are derived from simultaneous stellar photography are used to constrain the photogrammetric reduction of the lunar surface photographs when cartographic products are generated. In addition, the altimeter measurements alone provide broad-scale topographic relief around the entire circumference of the moon. These data are useful in investigating the selenodetic figure of the moon and may provide information regarding gravitational anomalies on the lunar far side.

Single photon laser altimeter simulator and statistical signal processing

Science.gov (United States)

Vacek, Michael; Prochazka, Ivan

2013-05-01

Spaceborne altimeters are common instruments onboard the deep space rendezvous spacecrafts. They provide range and topographic measurements critical in spacecraft navigation. Simultaneously, the receiver part may be utilized for Earth-to-satellite link, one way time transfer, and precise optical radiometry. The main advantage of single photon counting approach is the ability of processing signals with very low signal-to-noise ratio eliminating the need of large telescopes and high power laser source. Extremely small, rugged and compact microchip lasers can be employed. The major limiting factor, on the other hand, is the acquisition time needed to gather sufficient volume of data in repetitive measurements in order to process and evaluate the data appropriately. Statistical signal processing is adopted to detect signals with average strength much lower than one photon per measurement. A comprehensive simulator design and range signal processing algorithm are presented to identify a mission specific altimeter configuration. Typical mission scenarios (celestial body surface landing and topographical mapping) are simulated and evaluated. The high interest and promising single photon altimeter applications are low-orbit (˜10 km) and low-radial velocity (several m/s) topographical mapping (asteroids, Phobos and Deimos) and landing altimetry (˜10 km) where range evaluation repetition rates of ˜100 Hz and 0.1 m precision may be achieved. Moon landing and asteroid Itokawa topographical mapping scenario simulations are discussed in more detail.

Airborne laser altimeter measurements of landscape topography

International Nuclear Information System (INIS)

Ritchie, J.C.

1995-01-01

Measurements of topography can provide a wealth of information on landscape properties for managing hydrologic and geologic systems and conserving natural and agricultural resources. This article discusses the application of an airborne laser altimeter to measure topography and other landscape surface properties. The airborne laser altimeter makes 4000 measurements per second with a vertical recording resolution of 5 cm. Data are collected digitally with a personal computer. A video camera, borehole sighted with the laser, records an image for locating flight lines. GPS data are used to locate flight line positions on the landscape. Laser data were used to measure vegetation canopy topography, height, cover, and distribution and to measure microtopography of the land surface and gullies with depths of 15–20 cm. Macrotopography of landscape profiles for segments up to 4 km were in agreement with available topographic maps but provided more detail. Larger gullies with and without vegetation, and stream channel cross sections and their associated floodplains have also been measured and reported in other publications. Landscape segments for any length could be measured for either micro- or macrotopography. Airborne laser altimeter measurements of landscape profiles can provide detailed information on landscape properties or specific needs that will allow better decisions on the design and location of structures (i.e., roads, pipe, and power lines) and for improving the management and conservation of natural and agricultural landscapes. (author)

Reliability of Entire Corneal Thickness Mapping in Normal Post-Laser in situ Keratomileusis and Keratoconus Eyes Using Long Scan Depth Spectral Domain Optical Coherence Tomography.

Science.gov (United States)

Xu, Zhe; Chen, Sisi; Yang, Chun; Huang, Shenghai; Shen, Meixiao; Wang, Yuanyuan

2018-01-01

To investigate the repeatability and reproducibility of mapping the entire corneal thickness using spectral domain optical coherence tomography (SD-OCT). Thirty normal eyes, 30 post-laser in situ keratomileusis (LASIK) surgery eyes, and 30 keratoconus eyes were analyzed. A custom-built long scan depth SD-OCT device was used to obtain entire corneal images. Ten-millimeter-diameter corneal thickness maps were generated by an automated segmentation algorithm. Intraclass correlation coefficients of repeatability (ICC1) and reproducibility (ICC2), and coefficients of repeatability (CoR1) and reproducibility (CoR2), were calculated to quantify the precision and accuracy of corneal pachymetry measurements using the Bland-Altman method. For SD-OCT measurements in healthy subjects, CoR1 and CoR2 were less than 5.00 and 5.53 μm. ICC1 and ICC2 were more than 0.997 and 0.996. For SD-OCT measurements in LASIK patients, CoR1 and CoR2 were less than 5.09 and 5.34 μm. ICC1 and ICC2 were more than 0.997 and 0.996. For SD-OCT measurements in keratoconus patients, CoR1 and CoR2 were less than 11.57 and 10.92 μm. ICC1 and ICC2 were more than 0.995 and 0.996. The measurements of corneal pachymetric mapping by long scan depth SD-OCT can be assessed over the entire corneal area with good repeatability and reproducibility. © 2017 S. Karger AG, Basel.

Modelling the formation of nanostructures on metal surface induced by femtosecond laser ablation

International Nuclear Information System (INIS)

Djouder, M.; Itina, T.E.; Deghiche, D.; Lamrous, O.

2012-01-01

We employ the particle-in-cell method to simulate the mechanisms of femtosecond (fs) laser interactions with a metallic target. The theoretical approach considers the solid as a gas of free electrons in a lattice of immobile ions and the laser fluences close to the ablation threshold. At first moments of the interaction, our simulations mapped out different nanostructures. We carefully characterized the rippling phase and found that its morphology is dependent on the distribution of the electron density and the period of the ripples depends on the laser intensity. The simulation method provides new insights into the mechanisms that are responsible for surface grating formation.

Modelling the formation of nanostructures on metal surface induced by femtosecond laser ablation

Energy Technology Data Exchange (ETDEWEB)

Djouder, M. [Laboratoire de Physique et Chimie Quantique, Universite Mouloud Mammeri de Tizi-ouzou, BP 17 RP, 15000 Tizi-Ouzou (Algeria); Itina, T.E. [Laboratoire Hubert Curien, UMR CNRS 5516/Universite Jean Monnet, 18 rue de Professeur Benoit Lauras, 42000 Saint-Etienne (France); Deghiche, D. [Laboratoire de Physique et Chimie Quantique, Universite Mouloud Mammeri de Tizi-ouzou, BP 17 RP, 15000 Tizi-Ouzou (Algeria); Lamrous, O., E-mail: omarlamrous@mail.ummto.dz [Laboratoire de Physique et Chimie Quantique, Universite Mouloud Mammeri de Tizi-ouzou, BP 17 RP, 15000 Tizi-Ouzou (Algeria)

2012-01-15

We employ the particle-in-cell method to simulate the mechanisms of femtosecond (fs) laser interactions with a metallic target. The theoretical approach considers the solid as a gas of free electrons in a lattice of immobile ions and the laser fluences close to the ablation threshold. At first moments of the interaction, our simulations mapped out different nanostructures. We carefully characterized the rippling phase and found that its morphology is dependent on the distribution of the electron density and the period of the ripples depends on the laser intensity. The simulation method provides new insights into the mechanisms that are responsible for surface grating formation.

Roughness Mapping on Various Vertical Scales Based on Full-Waveform Airborne Laser Scanning Data

Directory of Open Access Journals (Sweden)

Wolfgang Wagner

2011-03-01

Full Text Available Roughness is an important input parameter for modeling of natural hazards such as floods, rock falls and avalanches, where it is basically assumed that flow velocities decrease with increasing roughness. Seeing roughness as a multi-scale level concept (i.e., ranging from fine-scale soil characteristics to description of understory and lower tree layer various roughness raster products were derived from the original full-waveform airborne laser scanning (FWF-ALS point cloud using two different types of roughness parameters, the surface roughness (SR and the terrain roughness (TR. For the calculation of the SR, ALS terrain points within a defined height range to the terrain surface are considered. For the parameterization of the SR, two approaches are investigated. In the first approach, a geometric description by calculating the standard deviation of plane fitting residuals of terrain points is used. In the second one, the potential of the derived echo widths are analyzed for the parameterization of SR. The echo width is an indicator for roughness and the slope of the target. To achieve a comparable spatial resolution of both SR layers, the calculation of the standard deviation of detrended terrain points requires a higher terrain point density than the SR parameterization using the echo widths. The TR describes objects (i.e., point clusters close but explicitly above the terrain surface, with 20 cm defined as threshold height value for delineation of the surface layer (i.e., forest floor layer. Two different empirically defined vegetation layers below the canopy layer were analyzed (TR I: 0.2 m to 1.0 m; TR II: 0.2 m to 3.0 m. A 1 m output grid cell size was chosen for all roughness parameters in order to provide consistency for further integration of high-resolution optical imagery. The derived roughness parameters were then jointly classified, together with a normalized Digital Surface Model (nDSM showing the height of objects (i

QUANTITATIVE FLOW-ANALYSIS AROUND AQUATIC ANIMALS USING LASER SHEET PARTICLE IMAGE VELOCIMETRY

NARCIS (Netherlands)

STAMHUIS, EJ; VIDELER, JJ

Two alternative particle image velocimetry (PIV) methods have been developed, applying laser light sheet illumination of particle-seeded flows around marine organisms, Successive video images, recorded perpendicular to a light sheet parallel to the main stream, were digitized and processed to map

Advanced mineral and lithological mapping using high spectral resolution TIR data from the active CO2 remote sensing system; CO2 laser wo mochiita kosupekutoru bunkaino netsusekigai remote sensing data no ganseki kobutsu shikibetsu eno oyo

Energy Technology Data Exchange (ETDEWEB)

Okada, K [Sumitomo Metal Mining Co. Ltd., Osaka (Japan); Hato, M [Earth Remote Sensing Data Analysis Center, Tokyo (Japan); Cudahy, T; Tapley, I

1997-05-27

A study was conducted on rock/mineral mapping technology for the metal ore deposit survey using MIRACO2LAS, an active type thermal infrared ray remote sensing system which was developed by CSIRO of Australia and is now the highest in spectral resolution in the world, and TIMS of NASA which is a passive type system. The area for the survey is the area of Olary/Broken Hill and Mt. Fitton of Australia. A good correlation is seen between the ground reflectance measured by MIRACO2LAS and the value measured by the chamber CO2 laser of rocks sampled at the above-mentioned area. In case that the width of spectral characteristics is below 300nm, the inspection ability by MIRACO2LAS`s high spectral resolution is more determined in mineral mapping as compared with TIMS which is large in band width. Minerals mapped using MIRACO2LAS are quartz, talc, amphibole, hornblende, garnet, supessartine, dolomite, magnesite, etc. 4 refs., 3 figs.

Photoinduced surface voltage mapping study for large perovskite single crystals

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiaojing; Liu, Yucheng; Gao, Fei; Yang, Zhou [Key Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, Shaanxi Engineering Laboratory for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi' an 710062 (China); Liu, Shengzhong, E-mail: liusz@snnu.edu.cn [Key Laboratory of Applied Surface and Colloid Chemistry, National Ministry of Education, Shaanxi Engineering Laboratory for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi' an 710062 (China); Dalian Institute of Chemical Physics, iChEM, Dalian National Laboratory for Clean Energy, Chinese Academy of Sciences, Dalian 116023 (China)

2016-05-02

Using a series of illumination sources, including white light (tungsten-halogen lamp), 445-nm, 532-nm, 635-nm, and 730-nm lasers, the surface photovoltage (SPV) images were mapped for centimeter-sized CH{sub 3}NH{sub 3}PbX{sub 3} (X = Cl, Br, I) perovskite single crystals using Kelvin probe force microscopy. The significant SPV signals were observed to be wavelength-dependent. We attribute the appreciable SPV to the built-in electric field in the space charge region. This study shines light into the understanding of photoinduced charge generation and separation processes at nanoscale to help advance the development of perovskite solar cells, optoelectronics, laser, photodetector, and light-emitting diode (LED).

Rapid Topographic Mapping Using TLS and UAV in a Beach-dune-wetland Environment: Case Study in Freeport, Texas, USA

Science.gov (United States)

Ding, J.; Wang, G.; Xiong, L.; Zhou, X.; England, E.

2017-12-01

Coastal regions are naturally vulnerable to impact from long-term coastal erosion and episodic coastal hazards caused by extreme weather events. Major geomorphic changes can occur within a few hours during storms. Prediction of storm impact, costal planning and resilience observation after natural events all require accurate and up-to-date topographic maps of coastal morphology. Thus, the ability to conduct rapid and high-resolution-high-accuracy topographic mapping is of critical importance for long-term coastal management and rapid response after natural hazard events. Terrestrial laser scanning (TLS) techniques have been frequently applied to beach and dune erosion studies and post hazard responses. However, TLS surveying is relatively slow and costly for rapid surveying. Furthermore, TLS surveying unavoidably retains gray areas that cannot be reached by laser pulses, particularly in wetland areas where lack of direct access in most cases. Aerial mapping using photogrammetry from images taken by unmanned aerial vehicles (UAV) has become a new technique for rapid topographic mapping. UAV photogrammetry mapping techniques provide the ability to map coastal features quickly, safely, inexpensively, on short notice and with minimal impact. The primary products from photogrammetry are point clouds similar to the LiDAR point clouds. However, a large number of ground control points (ground truth) are essential for obtaining high-accuracy UAV maps. The ground control points are often obtained by GPS survey simultaneously with the TLS survey in the field. The GPS survey could be a slow and arduous process in the field. This study aims to develop methods for acquiring a huge number of ground control points from TLS survey and validating point clouds obtained from photogrammetry with the TLS point clouds. A Rigel VZ-2000 TLS scanner was used for developing laser point clouds and a DJI Phantom 4 Pro UAV was used for acquiring images. The aerial images were processed with the

Hybrid Map-Based Navigation Method for Unmanned Ground Vehicle in Urban Scenario

Directory of Open Access Journals (Sweden)

Huiyan Chen

2013-07-01

Full Text Available To reduce the data size of metric map and map matching computational cost in unmanned ground vehicle self-driving navigation in urban scenarios, a metric-topological hybrid map navigation system is proposed in this paper. According to the different positioning accuracy requirements, urban areas are divided into strong constraint (SC areas, such as roads with lanes, and loose constraint (LC areas, such as intersections and open areas. As direction of the self-driving vehicle is provided by traffic lanes and global waypoints in the road network, a simple topological map is fit for the navigation in the SC areas. While in the LC areas, the navigation of the self-driving vehicle mainly relies on the positioning information. Simultaneous localization and mapping technology is used to provide a detailed metric map in the LC areas, and a window constraint Markov localization algorithm is introduced to achieve accurate position using laser scanner. Furthermore, the real-time performance of the Markov algorithm is enhanced by using a constraint window to restrict the size of the state space. By registering the metric maps into the road network, a hybrid map of the urban scenario can be constructed. Real unmanned vehicle mapping and navigation tests demonstrated the capabilities of the proposed method.

Instruments and Methods: A Low-Cost Glacier-Mapping System

DEFF Research Database (Denmark)

Christensen, Erik Lintz; Reeh, Niels; Forsberg, René

2000-01-01

the capability of acquiring accurate data on location and ice-surface elevation, and adequate-quality data on ice thickness. The system has been applied successfully in mapping the Nioghalvfjerdsfjorden glacier, northeast Greenland, in spite of the difficult conditions with melting water on the glacier surface....... The measurements from the floating part of the glacier have been evaluated by comparison of radar data with laser-altimeter and in situ measurements....

Implementation of laser speckle contrast analysis as connection kit for mobile phone for assessment of skin blood flow

Science.gov (United States)

Jakovels, Dainis; Saknite, Inga; Spigulis, Janis

2014-05-01

Laser speckle contrast analysis (LASCA) offers a non-contact, full-field, and real-time mapping of capillary blood flow and can be considered as an alternative method to Laser Doppler perfusion imaging. LASCA technique has been implemented in several commercial instruments. However, these systems are still too expensive and bulky to be widely available. Several optical techniques have found new implementations as connection kits for mobile phones thus offering low cost screening devices. In this work we demonstrate simple implementation of LASCA imaging technique as connection kit for mobile phone for primary low-cost assessment of skin blood flow. Stabilized 650 nm and 532 nm laser diode modules were used for LASCA illumination. Dual wavelength illumination could provide additional information about skin hemoglobin and oxygenation level. The proposed approach was tested for arterial occlusion and heat test. Besides, blood flow maps of injured and provoked skin were demonstrated.

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

TESTING OF LAND COVER CLASSIFICATION FROM MULTISPECTRAL AIRBORNE LASER SCANNING DATA

Directory of Open Access Journals (Sweden)

K. Bakuła

2016-06-01

Full Text Available Multispectral Airborne Laser Scanning provides a new opportunity for airborne data collection. It provides high-density topographic surveying and is also a useful tool for land cover mapping. Use of a minimum of three intensity images from a multiwavelength laser scanner and 3D information included in the digital surface model has the potential for land cover/use classification and a discussion about the application of this type of data in land cover/use mapping has recently begun. In the test study, three laser reflectance intensity images (orthogonalized point cloud acquired in green, near-infrared and short-wave infrared bands, together with a digital surface model, were used in land cover/use classification where six classes were distinguished: water, sand and gravel, concrete and asphalt, low vegetation, trees and buildings. In the tested methods, different approaches for classification were applied: spectral (based only on laser reflectance intensity images, spectral with elevation data as additional input data, and spectro-textural, using morphological granulometry as a method of texture analysis of both types of data: spectral images and the digital surface model. The method of generating the intensity raster was also tested in the experiment. Reference data were created based on visual interpretation of ALS data and traditional optical aerial and satellite images. The results have shown that multispectral ALS data are unlike typical multispectral optical images, and they have a major potential for land cover/use classification. An overall accuracy of classification over 90% was achieved. The fusion of multi-wavelength laser intensity images and elevation data, with the additional use of textural information derived from granulometric analysis of images, helped to improve the accuracy of classification significantly. The method of interpolation for the intensity raster was not very helpful, and using intensity rasters with both first and

New solid laser: Ceramic laser. From ultra stable laser to ultra high output laser

International Nuclear Information System (INIS)

Ueda, Kenichi

2006-01-01

An epoch-making solid laser is developed. It is ceramic laser, polycrystal, which is produced as same as glass and shows ultra high output. Ti 3+ :Al 2 O 3 laser crystal and the CPA (chirped pulse amplification) technique realized new ultra high output lasers. Japan has developed various kinds of ceramic lasers, from 10 -2 to 67 x 10 3 w average output, since 1995. These ceramic lasers were studied by gravitational radiation astronomy. The scattering coefficient of ceramic laser is smaller than single crystals. The new fast ignition method is proposed by Institute of Laser Engineering of Osaka University, Japan. Ultra-intense short pulse laser can inject the required energy to the high-density imploded core plasma within the core disassembling time. Ti 3+ :Al 2 O 3 crystal for laser, ceramic YAG of large caliber for 100 kW, transparent laser ceramic from nano-crystals, crystal grain and boundary layer between grains, the scattering coefficient of single crystal and ceramic, and the derived release cross section of Yb:YAG ceramic are described. (S.Y.)

Crystal Structure and Functional Characterization of the Complement Regulator Mannose-binding Lectin (MBL)/Ficolin-associated Protein-1 (MAP-1)

DEFF Research Database (Denmark)

Skjoedt, M.-o.; Roversi, P.; Hummelshoj, T.

2012-01-01

.5 nM, respectively. We studied structural aspects of MAP-1 and could show by multi-angle laser light scattering that MAP-1 forms a calcium-dependent homo-dimer in solution. We were able to determine the crystal structure of MAP-1, which also contains a head-to-tail dimer approximately 146 Angstrom...... long. This structure of MAP-1 also enables modeling and assembly of the MASP-1 molecule in its entirety. Finally we found that MAP-1 competes with all three MASPs for ligand binding and is able to mediate a strong dose dependent inhibitory effect on the lectin pathway activation, as measured by levels...

Photodissociation of Small Molecules and Photoionization of Free Radicals Using the VUV Velocity-Map Imaging Photoion and Photoelectron Method

Science.gov (United States)

Gao, Hong

The tunable vacuum ultraviolet (VUV) laser generated through the two-photon resonance-enhanced four-wave mixing scheme is combined with the newly developed time-slice velocity map imaging photoion method to study the photodissociation of small molecules in the VUV region, and with the velocity map imaging photoelectron method to study the photoionization of free radicals. The photodissociation dynamics of NO in the energy region around 13.5 eV has been investigated. Branching ratios of the three lowest dissociation channels of 12C 16O that produce C(3P) + O(3P), C( 1D) + O(3P) and C(3P) + O(1D) are measured for the first time in the VUV region from 102,500 cm-1 to 110,500 cm-1, valuable information of the dissociation dynamics for this prototype system has been deduced. We demonstrated an experiment that has two independently tunable VUV lasers and a time-slice velocity map imaging setup, this provides us a global way to perform systematic state-selected photodissociation of small molecules via state-selected detection of the atomic products in the VUV region. The velocity map imaging photoelectron method was successfully used to obtain the photoelectron spectrum of the propargyl radical (C3H3) via a single VUV photoionization process. The propargyl radical is generated by the 193 nm laser photodissociation of the precursor C3H3Cl. This is the first time that the velocity map imaging photoelectron method is used to get the photoelectron spectra of free radicals, indicating that it is a powerful technique for studying the photoionization of free radicals which are always hard to be produced with high enough number densities for spectroscopic studies. This dissertation is mainly based on the following peer-reviewed journal articles: 1. Hong Gao, Yang Pan, Lei Yang, Jingang Zhou, C. Y. Ng and William M. Jackson. "Time-slice velocity-map ion imaging studies of the Photodissociation of NO in the vacuum ultraviolet region", the Journal of Chemical Physics, 136, 134302

Characterization of HR coatings for the megajoule laser transport mirrors

International Nuclear Information System (INIS)

Fornier, A.; Cordillot, C.; Bernardino, D.; Lam, O.; Roussel, A.

1997-01-01

One of the concerns with the Megajoule Laser design is the laser-induced damage threshold of the transport mirrors. Earlier studies have shown that the main constraint on the laser damage threshold comes from nodules at the mirror surface. It is therefore important to restrict the number of such nodules. SFIM-ODS, in close collaboration with CEL-V, has initiated a special study to characterize these nodules as precisely as possible. The objective of the study is twofold: (1) to determine the origin of the nodules and subsequently to adapt the mirror fabrication process in order to limit their formation, (2) to analyze their shapes and dimensions in order to ascertain which nodules are critical for laser-induced damage. To understand the origin of the nodules and their effect on the laser damage threshold, the mirrors are characterized using various methods, (3) absorption and scatter mapping: does the presence of nodules result in specific absorption patterns? (4) surface analysis by atomic force microscopy: to characterize nodule shape and dimensions, (5) Focused Ion Beam (FIB) cutting of nodules: to locate the seed initiating the nodule (on the substrate or in the stack), and to characterize the seed shape and composition (contamination, material spatter during evaporation, etc.), and (6) laser damage threshold measurements: to determine the laser damage threshold of the mirror and study the behavior of nodules under laser irradiation depending on their dimensions and shape

Fatigue properties of dissimilar metal laser welded lap joints

Science.gov (United States)

Dinsley, Christopher Paul

This work involves laser welding austenitic and duplex stainless steel to zinc-coated mild steel, more specifically 1.2mm V1437, which is a Volvo Truck Coiporation rephosphorised mild steel. The work investigates both tensile and lap shear properties of similar and dissimilar metal laser welded butt and lap joints, with the majority of the investigation concentrating on the fatigue properties of dissimilar metal laser welded lap joints. The problems encountered when laser welding zinc-coated steel are addressed and overcome with regard to dissimilar metal lap joints with stainless steel. The result being the production of a set of guidelines for laser welding stainless steel to zinc-coated mild steel. The stages of laser welded lap joint fatigue life are defined and the factors affecting dissimilar metal laser welded lap joint fatigue properties are analysed and determined; the findings suggesting that dissimilar metal lap joint fatigue properties are primarily controlled by the local stress at the internal lap face and the early crack growth rate of the material at the internal lap face. The lap joint rotation, in turn, is controlled by sheet thickness, weld width and interfacial gap. Laser welded lap joint fatigue properties are found to be independent of base material properties, allowing dissimilar metal lap joints to be produced without fatigue failure occurring preferentially in the weaker parent material, irrespective of large base material property differences. The effects of Marangoni flow on the compositions of the laser weld beads are experimentally characterised. The results providing definite proof of the stirring mechanism within the weld pool through the use of speeds maps for chromium and nickel. Keywords: Laser welding, dissimilar metal, Zinc-coated mild steel, Austenitic stainless steel, Duplex stainless steel, Fatigue, Lap joint rotation, Automotive.

A Radar/Radiometer Instrument for Mapping Soil Moisture and Ocean Salinity

Science.gov (United States)

Hildebrand, Peter H.; Hilliard, Laurence; Rincon, Rafael; LeVine, David; Mead, James

2003-01-01

The RadSTAR instrument combines an L-band, digital beam-forming radar with an L-band synthetic aperture, thinned array (STAR) radiometer. The RadSTAR development will support NASA Earth science goals by developing a novel, L-band scatterometer/ radiometer that measures Earth surface bulk material properties (surface emissions and backscatter) as well as surface characteristics (backscatter). Present, real aperture airborne L-Band active/passive measurement systems such as the JPUPALS (Wilson, et al, 2000) provide excellent sampling characteristics, but have no scanning capabilities, and are extremely large; the huge JPUPALS horn requires a the C-130 airborne platform, operated with the aft loading door open during flight operation. The approach used for the upcoming Aquarius ocean salinity mission or the proposed Hydros soil mission use real apertures with multiple fixed beams or scanning beams. For real aperture instruments, there is no upgrade path to scanning over a broad swath, except rotation of the whole aperture, which is an approach with obvious difficulties as aperture size increases. RadSTAR will provide polarimetric scatterometer and radiometer measurements over a wide swath, in a highly space-efficient configuration. The electronic scanning approaches provided through STAR technology and digital beam forming will enable the large L-band aperture to scan efficiently over a very wide swath. RadSTAR technology development, which merges an interferometric radiometer with a digital beam forming scatterometer, is an important step in the path to space for an L-band scatterometer/radiometer. RadSTAR couples a patch array antenna with a 1.26 GHz digital beam forming radar scatterometer and a 1.4 GHz STAR radiometer to provide Earth surface backscatter and emission measurements in a compact, cross-track scanning instrument with no moving parts. This technology will provide the first L-band, emission and backscatter measurements in a compact aircraft instrument

Transverse Laser Beam Shaping in High Brightness Electron Gun at ATF

CERN Document Server

Roychowdhury, S

2005-01-01

The brightness of electron beams from a photo injector is influenced by the transverse and longitudinal distribution of the laser beam illuminating the cathode. Previous studies at Brookhaven Accelerator Test Facility have shown that formation of an ideal e-beam with lowest transverse emittance requires uniform circular distribution of the emitted electrons. The use of the uniformly distributed power of the laser beam may not lead to that of the emitted electrons because of the non-uniform quantum efficiency. A proper shaping of the laser beam can compensate for this non-uniformity. In this paper we describe the use of digital light processing (DLP) technique based on digital mirror device (DMD) for spatial modulation of the laser beam, for measurements of the quantum efficiency map, and for creating the desirable e-beam density profiles. A DMD is aμelectronic mechanical system (MEMS) comprising of millions of highly reflectiveμmirrors controlled by underlying electronics. We present exper...

[Study on the change of optical zone after femtosecond laser assisted laser in situ keratomileusis].

Science.gov (United States)

Li, H; Chen, M; Tian, L; Li, D W; Peng, Y S; Zhang, F F

2018-01-11

Objective: To explore the change of optical zone after femtosecond laser assisted laser in sitn keratomileusis(FS-LASIK) so as to provide the reference for measurement and design of clinical optical zone. Methods: This retrospective case series study covers 41 eyes of 24 patients (7 males and 17 females, aged from 18 to 42 years old) with myopia and myopic astigmatism who have received FS-LASIK surgery at Corneal Refractive Department of Qingdao Eye Hospital and completed over 6 months of clinical follow-up. Pentacam system (with the application of 6 corneal topographic map modes including: the pure axial curvature topographic map, the pure tangential curvature topographic map, the axial curvature difference topographic map, the tangential curvature difference topographic map, the postoperative front elevation map and the corneal thickness difference topographic map), combined with transparent concentric software (a system independently developed by Qingdao Eye Hospital) was used to measure the optical zone at 1, 3 and 6 months postoperatively, the optical zone diameters measurement results among different follow-up times in group were analyzed with the repeated measures analysis of variance, and the actual measured values and the theoretical design values of the optical zone were analyzed with independent-samples t-testing. Spearman correlation coefficient ( r(s) ) have been applied to evaluate the relationship between postoperative optical zone measurement values and the potential influencing factors. Results: The optical zone diameters measured by pure axial curvature topographic map at 1, 3 and 6 months after FS-LASIK showed (6.55±0.50)mm, (6.50±0.53)mm and (6.48±0.53)mm respectively. The differences between values are of no statistical significance ( F= 1.60, P= 0.21), the optical zone diameter measured by pure tangential curvature topographic map at 1, 3 and 6 months after FS-LASIK showed (5.44±0.46)mm, (5.46±0.52)mm and (5.44±0.50)mm respectively, the

IMPROVED UAV-BORNE 3D MAPPING BY FUSING OPTICAL AND LASERSCANNER DATA

Directory of Open Access Journals (Sweden)

B. Jutzi

2013-08-01

Full Text Available In this paper, a new method for fusing optical and laserscanner data is presented for improved UAV-borne 3D mapping. We propose to equip an unmanned aerial vehicle (UAV with a small platform which includes two sensors: a standard low-cost digital camera and a lightweight Hokuyo UTM-30LX-EW laserscanning device (210 g without cable. Initially, a calibration is carried out for the utilized devices. This involves a geometric camera calibration and the estimation of the position and orientation offset between the two sensors by lever-arm and bore-sight calibration. Subsequently, a feature tracking is performed through the image sequence by considering extracted interest points as well as the projected 3D laser points. These 2D results are fused with the measured laser distances and fed into a bundle adjustment in order to obtain a Simultaneous Localization and Mapping (SLAM. It is demonstrated that an improvement in terms of precision for the pose estimation is derived by fusing optical and laserscanner data.

Disruptive laser diode source for embedded LIDAR sensors

Science.gov (United States)

Canal, Celine; Laugustin, Arnaud; Kohl, Andreas; Rabot, Olivier

2017-02-01

Active imaging based on laser illumination is used in various fields such as medicine, security, defense, civil engineering and in the automotive sector. In this last domain, research and development to bring autonomous vehicles on the roads has been intensified these last years with an emphasis on lidar technology that is probably the key to achieve full automation level. Based on time-of-flight measurements, the profile of objects can be measured together with their location in various conditions, creating a 3D mapping of the environment. To be embedded on a vehicle as advanced driver assistance systems (ADAS), these sensors require compactness, low-cost and reliability, as it is provided by a flash lidar. An attractive candidate, especially with respect to cost reduction, for the laser source integrated in these devices is certainly laser diodes as long as they can provide sufficiently short pulses with a high energy. A recent breakthrough in laser diode and diode driver technology made by Quantel (Les Ulis, France) now allows laser emission higher than 1 mJ with pulses as short as 12 ns in a footprint of 4x5 cm2 (including both the laser diode and driver) and an electrical-to-optical conversion efficiency of the whole laser diode source higher than 25% at this level of energy. The components used for the laser source presented here can all be manufactured at low cost. In particular, instead of having several individual laser diodes positioned side by side, the laser diodes are monolithically integrated on a single semiconductor chip. The chips are then integrated directly on the driver board in a single assembly step. These laser sources emit in the range of 800-1000 nm and their emission is considered to be eye safe when taking into account the high divergence of the output beam and the aperture of possible macro lenses so that they can be used for end consumer applications. Experimental characterization of these state-of-the-art pulsed laser diode sources

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.

Mapping of aggregated floodplain plant communities using image fusion of CASI and LiDAR data

NARCIS (Netherlands)

Verrelst, J.; Geerling, G.W.; Sykora, K.V.; Clevers, J.G.P.W.

2009-01-01

Combined optical and laser altimeter data offer the potential to map and monitor plant communities based on their spectral and structural characteristics. A problem unresolved is, however, that narrowly defined plant communities, i.e. plant communities at a low hierarchical level of classification

Oil spill sensing in marine and coastal environments using laser-based sensors

International Nuclear Information System (INIS)

Brown, C. E.; Fingas, M. F.

1998-01-01

A prototype laser environmental airborne fluorosensor (LEAF) under development by the Environmental Protection Service of Environment Canada, which has the ability to detect and classify oil on water, land and conditions of snow and ice, real-time from an airborne platform, was described. Also under development are a scanning laser environmental airborne fluorosensor (SLEAF) to detect and map oil in complex marine and shoreline environments where other nonspecific sensors are not effective, and a laser ultrasonic remote sensing of oil thickness (LURSOT) sensor, which is expected to provide a measurement of oil thickness from an airborne platform. Details of each of these remote sensing technologies are provided, along with a discussion of expected benefits to the oil spill response community. 12 refs

Altimetric surveying with airborne laser system; Medicao altimetrica utilizando sistema a laser aerotransportado

Energy Technology Data Exchange (ETDEWEB)

Sallem Filho, Silas; Paoletto, Silvia M.; Bonatto, Amarildo [Esteio Engenharia, Curitiba, PR (Brazil)

2003-07-01

Airborne Laser Scanning (ALS) makes faster and more accurate the obtaining of Digital Elevation Model and Digital Terrain Model compared to conventional photogrammetry. The system generates Laser pulses towards the terrain, perpendicular to the flight line, scanning the terrain surface and recording the distances from the sensor to the soil for each pulse . The main characteristics of the system is the measurement of the first and the last return for each pulse, allowing the objects identification that are above the ground like vegetation. With this function it is possible the determination of volumes and biomass estimate, besides the virtual removal of vegetation covering. The Digital Terrain Models are used for Digital Orthophotos rectification and to obtain contour lines for topography maps. The correct points classification according the elevation, allows the identification of man-made features road and river crossings and human use in the the pipeline corridor. Some additional products, as hypsometric images and intensity images helps in the identification of features on pipeline projects as well as the obtaining of the obstacles height. (author)

Creep deformation behavior in eutectic Sn-Ag solder joints using a novel mapping technique

Energy Technology Data Exchange (ETDEWEB)

Lucas, J.P.; Guo, F.; McDougall, J.; Bieler, T.R.; Subramanian, K.N.; Park, J.K.

1999-11-01

Creep deformation behavior was measured for 60--100 {micro}m thick solder joints. The solder joints investigated consisted of: (1) non-composite solder joints made with eutectic Sn-Ag solder, and (2) composite solder joints with eutectic Sn-Ag solder containing 20 vol.%, 5 {micro}m diameter in-situ Cu{sub 6}Sn{sub 5} intermetallic reinforcements. All creep testing in this study was carried out at room temperature. Qualitative and quantitative assessment of creep deformation was characterized on the solder joints. Creep deformation was analyzed using a novel mapping technique where a geometrical-regular line pattern was etched over the entire solder joint using excimer laser ablation. During creep, the laser-ablation (LA) pattern becomes distorted due to deformation in the solder joint. By imaging the distortion of laser-ablation patterns using the SEM, actual deformation mapping for the entire solder joint is revealed. The technique involves sequential optical/digital imaging of the deformation versus time history during creep. By tracing and recording the deformation of the LA patterns on the solder over intervals of time, local creep data are obtained in many locations in the joint. This analysis enables global and localized creep shear strains and strain rate to be determined.

Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle's Mapping and Quantification in Organ Tissue

Science.gov (United States)

Sancey, Lucie; Motto-Ros, Vincent; Kotb, Shady; Wang, Xiaochun; Lux, François; Panczer, Gérard; Yu, Jin; Tillement, Olivier

2014-01-01

Emission spectroscopy of laser-induced plasma was applied to elemental analysis of biological samples. Laser-induced breakdown spectroscopy (LIBS) performed on thin sections of rodent tissues: kidneys and tumor, allows the detection of inorganic elements such as (i) Na, Ca, Cu, Mg, P, and Fe, naturally present in the body and (ii) Si and Gd, detected after the injection of gadolinium-based nanoparticles. The animals were euthanized 1 to 24 hr after intravenous injection of particles. A two-dimensional scan of the sample, performed using a motorized micrometric 3D-stage, allowed the infrared laser beam exploring the surface with a lateral resolution less than 100 μm. Quantitative chemical images of Gd element inside the organ were obtained with sub-mM sensitivity. LIBS offers a simple and robust method to study the distribution of inorganic materials without any specific labeling. Moreover, the compatibility of the setup with standard optical microscopy emphasizes its potential to provide multiple images of the same biological tissue with different types of response: elemental, molecular, or cellular. PMID:24962015

Laser wafering for silicon solar

International Nuclear Information System (INIS)

Friedmann, Thomas Aquinas; Sweatt, William C.; Jared, Bradley Howell

2011-01-01

Current technology cuts solar Si wafers by a wire saw process, resulting in 50% 'kerf' loss when machining silicon from a boule or brick into a wafer. We want to develop a kerf-free laser wafering technology that promises to eliminate such wasteful wire saw processes and achieve up to a ten-fold decrease in the g/W p (grams/peak watt) polysilicon usage from the starting polysilicon material. Compared to today's technology, this will also reduce costs (∼20%), embodied energy, and green-house gas GHG emissions (∼50%). We will use short pulse laser illumination sharply focused by a solid immersion lens to produce subsurface damage in silicon such that wafers can be mechanically cleaved from a boule or brick. For this concept to succeed, we will need to develop optics, lasers, cleaving, and high throughput processing technologies capable of producing wafers with thicknesses < 50 (micro)m with high throughput (< 10 sec./wafer). Wafer thickness scaling is the 'Moore's Law' of silicon solar. Our concept will allow solar manufacturers to skip entire generations of scaling and achieve grid parity with commercial electricity rates. Yet, this idea is largely untested and a simple demonstration is needed to provide credibility for a larger scale research and development program. The purpose of this project is to lay the groundwork to demonstrate the feasibility of laser wafering. First, to design and procure on optic train suitable for producing subsurface damage in silicon with the required damage and stress profile to promote lateral cleavage of silicon. Second, to use an existing laser to produce subsurface damage in silicon, and third, to characterize the damage using scanning electron microscopy and confocal Raman spectroscopy mapping.

Laser wafering for silicon solar.

Energy Technology Data Exchange (ETDEWEB)

Friedmann, Thomas Aquinas; Sweatt, William C.; Jared, Bradley Howell

2011-03-01

Current technology cuts solar Si wafers by a wire saw process, resulting in 50% 'kerf' loss when machining silicon from a boule or brick into a wafer. We want to develop a kerf-free laser wafering technology that promises to eliminate such wasteful wire saw processes and achieve up to a ten-fold decrease in the g/W{sub p} (grams/peak watt) polysilicon usage from the starting polysilicon material. Compared to today's technology, this will also reduce costs ({approx}20%), embodied energy, and green-house gas GHG emissions ({approx}50%). We will use short pulse laser illumination sharply focused by a solid immersion lens to produce subsurface damage in silicon such that wafers can be mechanically cleaved from a boule or brick. For this concept to succeed, we will need to develop optics, lasers, cleaving, and high throughput processing technologies capable of producing wafers with thicknesses < 50 {micro}m with high throughput (< 10 sec./wafer). Wafer thickness scaling is the 'Moore's Law' of silicon solar. Our concept will allow solar manufacturers to skip entire generations of scaling and achieve grid parity with commercial electricity rates. Yet, this idea is largely untested and a simple demonstration is needed to provide credibility for a larger scale research and development program. The purpose of this project is to lay the groundwork to demonstrate the feasibility of laser wafering. First, to design and procure on optic train suitable for producing subsurface damage in silicon with the required damage and stress profile to promote lateral cleavage of silicon. Second, to use an existing laser to produce subsurface damage in silicon, and third, to characterize the damage using scanning electron microscopy and confocal Raman spectroscopy mapping.

Novel short-pulse laser diode source for high-resolution 3D flash lidar

Science.gov (United States)

Canal, Celine; Laugustin, Arnaud; Kohl, Andreas; Rabot, Olivier

2017-06-01

Imaging based on laser illumination is present in various fields of applications such as medicine, security, defense, civil engineering and in the automotive sector. In this last domain, research and development to bring autonomous vehicles on the roads has been intensified the recent years. Among the various technologies currently studied, automotive lidars are a fast-growing one due to their accuracy to detect a wide range of objects at distances up to a few hundreds of meters in various weather conditions. First commercialized devices for ADAS were laser scanners. Since then, new architectures have recently appeared such as solid-state lidar and flash lidar that offer a higher compactness, robustness and a cost reduction. Flash lidars are based on time-of-flight measurements, with the particularity that they do not require beam scanners because only one short laser pulse with a large divergence is used to enlighten the whole scene. Depth of encountered objects can then be recovered from measurement of echoed light at once, hence enabling real-time 3D mapping of the environment. This paper will bring into the picture a cutting edge laser diode source that can deliver millijoule pulses as short as 12 ns, which makes them highly suitable for integration in flash lidars. They provide a 100-kW peak power highly divergent beam in a footprint of 4x5 cm2 (including both the laser diode and driver) and with a 30-% electrical-to-optical efficiency, making them suitable for integration in environments in which compactness and power consumption are a priority. Their emission in the range of 800-1000 nm is considered to be eye safe when taking into account the high divergence of the output beam. An overview of architecture of these state-of-the-art pulsed laser diode sources will be given together with some solutions for their integration in 3D mapping systems. Future work leads will be discussed for miniaturization of the laser diode and drastic cost reduction.

The Ganymede Laser Altimeter (GALA)

Science.gov (United States)

Hussmann, H.

2015-12-01

The Ganymede Laser Altimeter (GALA) is one of the instruments selected for ESA's Jupiter Icy Moons Explorer (JUICE). A fundamental goal of any exploratory space mission is to characterize and measure the shape, topography, and rotation of the target bodies. A state of the art tool for this task is laser altimetry because it can provide absolute topographic height and position with respect to a body centered reference system. With respect to Ganymede, the GALA instrument aims at mapping of global, regional and local topography; confirming the global subsurface ocean and further characterization of the water-ice/liquid shell by monitoring the dynamic response of the ice shell to tidal forces; providing constraints on the forced physical librations and spin-axis obliquity; determining Ganymede's shape; obtaining detailed topographic profiles across the linear features of grooved terrain, impact structures, possible cryo-volcanic features and other different surface units; providing information about slope, roughness and albedo (at 1064nm) of Ganymede's surface. GALA uses the direct-detection (classical) approach of laser altimetry. Laser pulses are emitted at a wavelength of 1064 nm by using an actively Q-switched Nd:Yag laser. The pulse energy and pulse repetition frequency are 17 mJ at 30 Hz, respectively. The emission time of each pulse is measured by the detector. The beam is reflected from the surface and received at a 25 cm diameter F/1 telescope. The returning laser pulse is refocused onto a silicon avalanche photodiode (APD) through back-end optics including a narrow bandpass interference filter for isolating the 1064 nm wavelength. The APD-signal is then amplified, sampled and fed to a digital range finder. The minimum acceptable SNR is approx. 1.2. This system determines the time of flight, pulse intensity, width and full shape. The GALA instrument is developed in collaboration of institutes and industry from Germany, Japan, Switzerland and Spain.

A novel fiber laser development for photoacoustic microscopy

Science.gov (United States)

Yavas, Seydi; Aytac-Kipergil, Esra; Arabul, Mustafa U.; Erkol, Hakan; Akcaalan, Onder; Eldeniz, Y. Burak; Ilday, F. Omer; Unlu, Mehmet B.

2013-03-01

Photoacoustic microscopy, as an imaging modality, has shown promising results in imaging angiogenesis and cutaneous malignancies like melanoma, revealing systemic diseases including diabetes, hypertension, tracing drug efficiency and assessment of therapy, monitoring healing processes such as wound cicatrization, brain imaging and mapping. Clinically, photoacoustic microscopy is emerging as a capable diagnostic tool. Parameters of lasers used in photoacoustic microscopy, particularly, pulse duration, energy, pulse repetition frequency, and pulse-to-pulse stability affect signal amplitude and quality, data acquisition speed and indirectly, spatial resolution. Lasers used in photoacoustic microscopy are typically Q-switched lasers, low-power laser diodes, and recently, fiber lasers. Significantly, the key parameters cannot be adjusted independently of each other, whereas microvasculature and cellular imaging, e.g., have different requirements. Here, we report an integrated fiber laser system producing nanosecond pulses, covering the spectrum from 600 nm to 1100 nm, developed specifically for photoacoustic excitation. The system comprises of Yb-doped fiber oscillator and amplifier, an acousto-optic modulator and a photonic-crystal fiber to generate supercontinuum. Complete control over the pulse train, including generation of non-uniform pulse trains, is achieved via the AOM through custom-developed field-programmable gate-array electronics. The system is unique in that all the important parameters are adjustable: pulse duration in the range of 1-3 ns, pulse energy up to 10 μJ, repetition rate from 50 kHz to 3 MHz. Different photocoustic imaging probes can be excited with the ultrabroad spectrum. The entire system is fiber-integrated; guided-beam-propagation rendersit misalignment free and largely immune to mechanical perturbations. The laser is robust, low-cost and built using readily available components.

2D elemental mapping of sections of human kidney stones using laser ablation inductively-coupled plasma-mass spectrometry: Possibilities and limitations

Energy Technology Data Exchange (ETDEWEB)

Vašinová Galiová, Michaela [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno (Czech Republic); Čopjaková, Renata; Škoda, Radek [Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Štěpánková, Kateřina; Vaňková, Michaela [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Kuta, Jan [Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 126/3, 625 00 Brno (Czech Republic); Prokeš, Lubomír [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Kynický, Jindřich [Department of Pedology and Geology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno (Czech Republic); and others

2014-10-01

A 213 nm Nd:YAG-based laser ablation (LA) system coupled to quadrupole-based inductively coupled plasma-mass spectrometer and an ArF* excimer-based LA-system coupled to a double-focusing sector field inductively coupled plasma-mass spectrometer were employed to study the spatial distribution of various elements in kidney stones (uroliths). Sections of the surfaces of uroliths were ablated according to line patterns to investigate the elemental profiles for the different urolith growth zones. This exploratory study was mainly focused on the distinguishing of the main constituents of urinary calculus fragments by means of LA-ICP-mass spectrometry. Changes in the ablation rate for oxalate and phosphate phases related to matrix density and hardness are discussed. Elemental association was investigated on the basis of 2D mapping. The possibility of using NIST SRM 1486 Bone Meal as an external standard for calibration was tested. It is shown that LA-ICP-MS is helpful for determination of the mineralogical composition and size of all phases within the analyzed surface area, for tracing down elemental associations and for documenting the elemental content of urinary stones. LA-ICP-MS results (elemental contents and maps) are compared to those obtained with electron microprobe analysis and solution analysis ICP-MS. - Highlights: • Elements in phosphate and oxalate urolith phases were quantified by LA-ICP-MS. • SRM NIST 1486 Bone Meal was proved suitable for quantification in uroliths. • Different ablation rates in particular phases were included at quantification. • Oxalate and apatite phases show opposite hardness order to natural minerals. • Uroliths were classified according to elemental association to phases.

Spatiotemporal hazard mapping of a flood event "migration" in a transboundary river basin as an operational tool in flood risk management

Science.gov (United States)

Perrou, Theodora; Papastergios, Asterios; Parcharidis, Issaak; Chini, Marco

2017-10-01

Flood disaster is one of the heaviest disasters in the world. It is necessary to monitor and evaluate the flood disaster in order to mitigate the consequences. As floods do not recognize borders, transboundary flood risk management is imperative in shared river basins. Disaster management is highly dependent on early information and requires data from the whole river basin. Based on the hypothesis that the flood events over the same area with same magnitude have almost identical evolution, it is crucial to develop a repository database of historical flood events. This tool, in the case of extended transboundary river basins, could constitute an operational warning system for the downstream area. The utility of SAR images for flood mapping, was demonstrated by previous studies but the SAR systems in orbit were not characterized by high operational capacity. Copernicus system will fill this gap in operational service for risk management, especially during emergency phase. The operational capabilities have been significantly improved by newly available satellite constellation, such as the Sentinel-1A AB mission, which is able to provide systematic acquisitions with a very high temporal resolution in a wide swath coverage. The present study deals with the monitoring of a transboundary flood event in Evros basin. The objective of the study is to create the "migration story" of the flooded areas on the basis of the evolution in time for the event occurred from October 2014 till May 2015. Flood hazard maps will be created, using SAR-based semi-automatic algorithms and then through the synthesis of the related maps in a GIS-system, a spatiotemporal thematic map of the event will be produced. The thematic map combined with TanDEM-X DEM, 12m/pixel spatial resolution, will define the non- affected areas which is a very useful information for the emergency planning and emergency response phases. The Sentinels meet the main requirements to be an effective and suitable

Laser assisted fabrication of random rough surfaces for optoelectronics

Energy Technology Data Exchange (ETDEWEB)

Brissonneau, V., E-mail: vincent.brissonneau@im2np.fr [Thales Optronique SA, Avenue Gay-Lussac, 78995 Elancourt (France); Institut Materiaux Microelectronique Nanosciences de Provence, Aix Marseille Universite, Avenue Escadrille Normandie Niemen, 13397 Marseille (France); Escoubas, L. [Institut Materiaux Microelectronique Nanosciences de Provence, Aix Marseille Universite, Avenue Escadrille Normandie Niemen, 13397 Marseille (France); Flory, F. [Institut Materiaux Microelectronique Nanosciences de Provence, Ecole Centrale Marseille, Marseille (France); Berginc, G. [Thales Optronique SA, Avenue Gay-Lussac, 78995 Elancourt (France); Maire, G.; Giovannini, H. [Institut Fresnel, Aix Marseille Universite, Avenue Escadrille Normandie Niemen, 13397 Marseille (France)

2012-09-15

Highlights: Black-Right-Pointing-Pointer Random rough surfaces are photofabricated using an argon ion laser. Black-Right-Pointing-Pointer Speckle and surface correlation function are linked. Black-Right-Pointing-Pointer Exposure beam is modified allowing tuning the correlation. Black-Right-Pointing-Pointer Theoretical examples are presented. Black-Right-Pointing-Pointer Experimental results are compared with theoretical expectation. - Abstract: Optical surface structuring shows great interest for antireflective or scattering properties. Generally, fabricated surface structures are periodical but random surfaces that offer new degrees of freedom and possibilities by the control of their statistical properties. We propose an experimental method to create random rough surfaces on silicon by laser processing followed by etching. A photoresist is spin coated onto a silicon substrate and then exposed to the scattering of a modified laser beam. The beam modification is performed by using a micromirror matrix allowing laser beam shaping. An example of tuning is presented. An image composed of two white circles with a black background is displayed and the theoretical shape of the correlation is calculated. Experimental surfaces are elaborated and the correlation function calculated from height mapping. We finally compared the experimental and theoretical correlation functions.

Aespoe Hard Rock Laboratory. The TASS-tunnel. Geological mapping

Energy Technology Data Exchange (ETDEWEB)

Hardenby, Carljohan (Vattenfall Power Consultant AB (Sweden)); Sigurdsson, Oskar (HAskGeokonsult AB (Sweden))

2010-12-15

The project entitled 'Sealing of tunnel at great depth' (Fintaetning av tunnel paa stort djup) needed a new tunnel in an area as undisturbed as possible and with cross-cutting water-bearing structures. The new tunnel, which was given the name TASS, was excavated on the -450 m level of SKB's Aespoe Hard Rock Laboratory (Aespoe HRL). The length of the tunnel is approximately 80 m and the theoretical tunnel area 19 m2. As is the case with all the other tunnels of the Aespoe HRL, the new tunnel has been geologically mapped. In addition, laser scanning combined with digital photography has been carried out. The tunnel was also used to test various types of explosives, borehole layouts and drilling techniques. The geological mapping of tunnel floor, walls and roof took place on four major occasions when a halt was made in tunnel excavation to allow for various tests. Before the mapping started on these occasions, laser scanning took place. The tunnel faces were mapped after each round (drilling, blasting and unloading). The present report describes the geological features of the tunnel and briefly how the laser scanning was performed. Water-bearing structures have been compared to similar structures in the neighbouring tunnels. The rock type names used here follow the old established Aespoe HRL nomenclature. Narrow (<0.1 m wide) dykes are normally mapped as fracture fillings. The dominating rock type is Aespoe diorite, which constitutes some 90 % of the rock mass. It is mostly mapped as fresh rock. . Minor constituents of the rock mass are fine-grained granite, hybrid rock, pegmatite, quartz veins/lenses and undifferentiated mafic rock. The mapping of fractures and deformation zones considers a number of parameters such as number of fractures, open/healed, width, length, description of fracture surfaces (roughness, planarity, etc), fracture filling, alteration and water. The deformation zones are discriminated into two main categories (&apos

Aespoe Hard Rock Laboratory. The TASS-tunnel. Geological mapping

International Nuclear Information System (INIS)

Hardenby, Carljohan; Sigurdsson, Oskar

2010-12-01

The project entitled 'Sealing of tunnel at great depth' (Fintaetning av tunnel paa stort djup) needed a new tunnel in an area as undisturbed as possible and with cross-cutting water-bearing structures. The new tunnel, which was given the name TASS, was excavated on the -450 m level of SKB's Aespoe Hard Rock Laboratory (Aespoe HRL). The length of the tunnel is approximately 80 m and the theoretical tunnel area 19 m 2 . As is the case with all the other tunnels of the Aespoe HRL, the new tunnel has been geologically mapped. In addition, laser scanning combined with digital photography has been carried out. The tunnel was also used to test various types of explosives, borehole layouts and drilling techniques. The geological mapping of tunnel floor, walls and roof took place on four major occasions when a halt was made in tunnel excavation to allow for various tests. Before the mapping started on these occasions, laser scanning took place. The tunnel faces were mapped after each round (drilling, blasting and unloading). The present report describes the geological features of the tunnel and briefly how the laser scanning was performed. Water-bearing structures have been compared to similar structures in the neighbouring tunnels. The rock type names used here follow the old established Aespoe HRL nomenclature. Narrow (<0.1 m wide) dykes are normally mapped as fracture fillings. The dominating rock type is Aespoe diorite, which constitutes some 90 % of the rock mass. It is mostly mapped as fresh rock. . Minor constituents of the rock mass are fine-grained granite, hybrid rock, pegmatite, quartz veins/lenses and undifferentiated mafic rock. The mapping of fractures and deformation zones considers a number of parameters such as number of fractures, open/healed, width, length, description of fracture surfaces (roughness, planarity, etc), fracture filling, alteration and water. The deformation zones are discriminated into two main categories ('increased fracturing' and

High repetition ration solid state switched CO2 TEA laser employed in industrial ultrasonic testing of aircraft parts

Science.gov (United States)

von Bergmann, Hubertus; Morkel, Francois; Stehmann, Timo

2015-02-01

Laser Ultrasonic Testing (UT) is an important technique for the non-destructive inspection of composite parts in the aerospace industry. In laser UT a high power, short pulse probe laser is scanned across the material surface, generating ultrasound waves which can be detected by a second low power laser system and are used to draw a defect map of the part. We report on the design and testing of a transversely excited atmospheric pressure (TEA) CO2 laser system specifically optimised for laser UT. The laser is excited by a novel solid-state switched pulsing system and utilises either spark or corona preionisation. It provides short output pulses of less than 100 ns at repetition rates of up to 1 kHz, optimised for efficient ultrasonic wave generation. The system has been designed for highly reliable operation under industrial conditions and a long term test with total pulse counts in excess of 5 billion laser pulses is reported.

Mapping out Map Libraries

Directory of Open Access Journals (Sweden)

Ferjan Ormeling

2008-09-01

Full Text Available Discussing the requirements for map data quality, map users and their library/archives environment, the paper focuses on the metadata the user would need for a correct and efficient interpretation of the map data. For such a correct interpretation, knowledge of the rules and guidelines according to which the topographers/cartographers work (such as the kind of data categories to be collected, and the degree to which these rules and guidelines were indeed followed are essential. This is not only valid for the old maps stored in our libraries and archives, but perhaps even more so for the new digital files as the format in which we now have to access our geospatial data. As this would be too much to ask from map librarians/curators, some sort of web 2.0 environment is sought where comments about data quality, completeness and up-to-dateness from knowledgeable map users regarding the specific maps or map series studied can be collected and tagged to scanned versions of these maps on the web. In order not to be subject to the same disadvantages as Wikipedia, where the ‘communis opinio’ rather than scholarship, seems to be decisive, some checking by map curators of this tagged map use information would still be needed. Cooperation between map curators and the International Cartographic Association ( ICA map and spatial data use commission to this end is suggested.

An ML-Based Radial Velocity Estimation Algorithm for Moving Targets in Spaceborne High-Resolution and Wide-Swath SAR Systems

Directory of Open Access Journals (Sweden)

Tingting Jin

2017-04-01

Full Text Available Multichannel synthetic aperture radar (SAR is a significant breakthrough to the inherent limitation between high-resolution and wide-swath (HRWS compared with conventional SAR. Moving target indication (MTI is an important application of spaceborne HRWS SAR systems. In contrast to previous studies of SAR MTI, the HRWS SAR mainly faces the problem of under-sampled data of each channel, causing single-channel imaging and processing to be infeasible. In this study, the estimation of velocity is equivalent to the estimation of the cone angle according to their relationship. The maximum likelihood (ML based algorithm is proposed to estimate the radial velocity in the existence of Doppler ambiguities. After that, the signal reconstruction and compensation for the phase offset caused by radial velocity are processed for a moving target. Finally, the traditional imaging algorithm is applied to obtain a focused moving target image. Experiments are conducted to evaluate the accuracy and effectiveness of the estimator under different signal-to-noise ratios (SNR. Furthermore, the performance is analyzed with respect to the motion ship that experiences interference due to different distributions of sea clutter. The results verify that the proposed algorithm is accurate and efficient with low computational complexity. This paper aims at providing a solution to the velocity estimation problem in the future HRWS SAR systems with multiple receive channels.

The Hydrosphere State (Hydros) Satellite Mission: An Earth System Pathfinder for Global Mapping of Soil Moisture and Land Freeze/Thaw

Science.gov (United States)

Entekhabi, D.; Njoku, E. G.; Spencer, M.; Kim, Y.; Smith, J.; McDonald, K. C.; vanZyl, J.; Houser, P.; Dorion, T.; Koster, R.;

High-energy harmonic mode-locked 2 μm dissipative soliton fiber lasers

International Nuclear Information System (INIS)

Yang, Nan; Tang, Yulong; Xu, Jianqiu

2015-01-01

High-pulse-energy harmonic mode-locking in 2 μm Tm-doped fiber lasers (TDFLs) is realized, for the first time, by using a short piece of anomalous dispersion gain fiber and the dissipative soliton mode-locking mechanism. Appropriately designing the cavity dispersion map and adjusting the cavity gain, stable harmonic mode-locking of the dissipative soliton TDFL from the 2nd to the 4th order is achieved, with the pulsing repetition rates and pulse energy being 43.4, 65.1, 86.8 MHz, and 6.27, 4.32 and 3.29 nJ, respectively. The harmonic laser pulse has a pulse width of ∼30 ps and a center wavelength of ∼1929 nm with a spectral bandwidth of ∼3.26 nm, giving a highly chirped laser pulse. Two types of soliton molecules are also observed in this laser system. (letter)

Stability diagrams for continuous wide-range control of two mutually delay-coupled semiconductor lasers

International Nuclear Information System (INIS)

Junges, Leandro; Gallas, Jason A C

2015-01-01

The dynamics of two mutually delay-coupled semiconductor lasers has been frequently studied experimentally, numerically, and analytically either for weak or strong detuning between the lasers. Here, we present a systematic numerical investigation spanning all detuning ranges. We report high-resolution stability diagrams for wide ranges of the main control parameters of the laser, as described by the Lang–Kobayashi model. In particular, we detail the parameter influence on dynamical performance and map the distribution of chaotic pulsations and self-generated periodic spiking with arbitrary periodicity. Special attention is given to the unfolding of regular pulse packages for both symmetric and non-symmetric configurations with respect to detuning. The influence of the delay –time on the self-organization of periodic and chaotic laser phases as a function of the coupling and detuning is also described in detail. (paper)

New developments in short-pulse eye safe lasers pay the way for future LADARs and 3D mapping performances

Science.gov (United States)

Pasmanik, Guerman; Latone, Kevin; Shilov, Alex; Shklovsky, Eugeni; Spiro, Alex; Tiour, Larissa

2005-06-01

We have demonstrated that direct excitation of 3rd Stokes Raman emission in crystal can produce short (few nanosecond) eye-safe pulses. Produced beam has very high quality and the pulse energy can be as high as tens of millijoules. For pulsed diode pumped solid state lasers the demonstrated repetition rate was 250 Hz but higher repetition rates are certainly achievable. It is important that tested schemes do not have strict requirements on laser pump parameters, namely beam divergence and frequency bandwidth. The obtained results are very relevant to the development of eye-safe lasers, such as the new generation of rangefinders, target designators, and laser tracking and pin-pointing devices, as well as remote 2D and 3D imaging systems.

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.

Analysis and Validation of ZY-3 02 Satellite Laser Altimetry Data

Directory of Open Access Journals (Sweden)

LI Guoyuan

2017-12-01

Full Text Available ZY-3 02 satellite loaded with Chinese first earth observing satellite laser altimeter,and has been launched successfully on 30th May,2016. In this paper,the theoretical accuracy of the laser altimeter is analyzed,and several experimental areas are used to verify the actual accuracy. At the same time,the application of the laser altimetry data in the field of space-borne photogrammetry is tested. The laser altimetry theoretical accuracy of ZY-3 02 satellite in the flat area (slope less than 2 degrees is about 0.85 m and 14.2 m in the elevation and planimetry direction,respectively. The effective laser altimetry data account for about 23.89%,and near the calibration field the elevation accuracy is 0.89 m,and planimetry accuracy is about 14.76 m. Moreover,the verified elevation accuracy is 1.09 m in the North China by high precision DSM terrain data,and laser footprint points accuracy on the surface of the Bohai inland sea is about 0.47 m. When the laser foot print point is used as elevation control point,the elevation accuracy of the ZY-3 02 satellite stereo images in Shaanxi Weinan can be increased from 11.54 m to 1.90 m without GCPs. Although ZY3-02 satellite laser altimeter is just a test,the results proved that the domestic satellite laser altimetry data can effectively improve the stereo images without GCPs,which will be valuable in the global mapping project. It is suggest that operational laser altimeter equip on the next satellite of ZY-3 serials.

An Integrated GNSS/INS/LiDAR-SLAM Positioning Method for Highly Accurate Forest Stem Mapping

Directory of Open Access Journals (Sweden)

Chuang Qian

2016-12-01

Full Text Available Forest mapping, one of the main components of performing a forest inventory, is an important driving force in the development of laser scanning. Mobile laser scanning (MLS, in which laser scanners are installed on moving platforms, has been studied as a convenient measurement method for forest mapping in the past several years. Positioning and attitude accuracies are important for forest mapping using MLS systems. Inertial Navigation Systems (INSs and Global Navigation Satellite Systems (GNSSs are typical and popular positioning and attitude sensors used in MLS systems. In forest environments, because of the loss of signal due to occlusion and severe multipath effects, the positioning accuracy of GNSS is severely degraded, and even that of GNSS/INS decreases considerably. Light Detection and Ranging (LiDAR-based Simultaneous Localization and Mapping (SLAM can achieve higher positioning accuracy in environments containing many features and is commonly implemented in GNSS-denied indoor environments. Forests are different from an indoor environment in that the GNSS signal is available to some extent in a forest. Although the positioning accuracy of GNSS/INS is reduced, estimates of heading angle and velocity can maintain high accurate even with fewer satellites. GNSS/INS and the LiDAR-based SLAM technique can be effectively integrated to form a sustainable, highly accurate positioning and mapping solution for use in forests without additional hardware costs. In this study, information such as heading angles and velocities extracted from a GNSS/INS is utilized to improve the positioning accuracy of the SLAM solution, and two information-aided SLAM methods are proposed. First, a heading angle-aided SLAM (H-aided SLAM method is proposed that supplies the heading angle from GNSS/INS to SLAM. Field test results show that the horizontal positioning accuracy of an entire trajectory of 800 m is 0.13 m and is significantly improved (by 70% compared to that

Shift of critical points in the parametrically modulated Henon map with coexisting attractors

International Nuclear Information System (INIS)

Saucedo-Solorio, J.M.; Pisarchik, A.N.; Aboites, V.

2002-01-01

We study how the critical point positions change in the parametrically modulated Henon map with coexisting period-1 and period-3 attractors. In particular, a new type of scaling law is found coinciding with that evidenced by laser experiments. We show that resonance phenomena play a crucial role in deformation of attractors and their basins of attraction

Large-Scale Mixed Temperate Forest Mapping at the Single Tree Level using Airborne Laser Scanning

Science.gov (United States)

Scholl, V.; Morsdorf, F.; Ginzler, C.; Schaepman, M. E.

2017-12-01

Monitoring vegetation on a single tree level is critical to understand and model a variety of processes, functions, and changes in forest systems. Remote sensing technologies are increasingly utilized to complement and upscale the field-based measurements of forest inventories. Airborne laser scanning (ALS) systems provide valuable information in the vertical dimension for effective vegetation structure mapping. Although many algorithms exist to extract single tree segments from forest scans, they are often tuned to perform well in homogeneous coniferous or deciduous areas and are not successful in mixed forests. Other methods are too computationally expensive to apply operationally. The aim of this study was to develop a single tree detection workflow using leaf-off ALS data for the canton of Aargau in Switzerland. Aargau covers an area of over 1,400km2 and features mixed forests with various development stages and topography. Forest type was classified using random forests to guide local parameter selection. Canopy height model-based treetop maxima were detected and maintained based on the relationship between tree height and window size, used as a proxy to crown diameter. Watershed segmentation was used to generate crown polygons surrounding each maximum. The location, height, and crown dimensions of single trees were derived from the ALS returns within each polygon. Validation was performed through comparison with field measurements and extrapolated estimates from long-term monitoring plots of the Swiss National Forest Inventory within the framework of the Swiss Federal Institute for Forest, Snow, and Landscape Research. This method shows promise for robust, large-scale single tree detection in mixed forests. The single tree data will aid ecological studies as well as forest management practices. Figure description: Height-normalized ALS point cloud data (top) and resulting single tree segments (bottom) on the Laegeren mountain in Switzerland.

Towards Automation in Landcover Mapping from LiDAR Data in Alpine Environment

Science.gov (United States)

Dorninger, Peter; Briese, Christian; Nothegger, Clemens; Klauser, Armin

2010-05-01

Digital terrain models derived from airborne LiDAR (often referred to as airborne laser scanning) are commonly used for various applications in geomorphology. The ongoing development in sensor technology makes flight campaigns with some 10 points per square meter economically feasible for large areas. Simultaneously, the achievable accuracy of the originally acquired points as well as those of the derived products increases due to improved measurement techniques. Additionally, full-waveform (FWF) laser scanning systems record the time-dependent strength of the backscattered signal. This allows for the determination of numerous points (i.e. echoes) for one emitted laser beam hitting multiple targets within its footprint. Practically, about five echoes may be determined from the digitized signal form. Furthermore, additional attributes can be determined for each echo. These are, for example, a reflectivity measure (amplitude), the widening of the echo (echo width), or the sequence of the echoes of a single shot. By considering the polar measurement range and atmospheric conditions, a physical calibration of such measurements is possible. The application of FWF information to increase the accuracy and the reliability of digital terrain models especially in areas with dense vegetation was shown by Doneus & Briese (2006). However, these additional attributes are rarely used for object or landcover classification. This is still the domain of automated image interpretation (e.g. Zebedin et al., 2006). Nevertheless, image interpretation has well known deficiencies in areas with vegetation or if shadows occur. Therefore, we tested a hybrid approach which uses conventional first echo / last echo (FE/LE) airborne laser scanning data (first and last pulse) and an RGB-orthophoto. The testing site is located in an alpine area in Tyrol, Austria. For the classification, topographic models, a slope map, a local roughness measure and a penetration ratio were determined from the

Assessment of Hydrogen Sulfide Minimum Detection Limits of an Open Path Tunable Diode Laser

Science.gov (United States)

During June 2007, U.S. EPA conducted a feasibility study to determine whether the EPA OTM 10 measurement approach, also known as radial plume mapping (RPM), was feasible. A Boreal open-path tunable diode laser (OP-TDL) to collect path-integrated hydrogen sulfide measurements alon...

Laser speckle imaging: a novel method for detecting dental erosion.

Directory of Open Access Journals (Sweden)

Nelson H Koshoji

Full Text Available Erosion is a highly prevalent condition known as a non-carious lesion that causes progressive tooth wear due to chemical processes that do not involve the action of bacteria. Speckle images proved sensitive to even minimal mineral loss from the enamel. The aim of the present study was to investigate the use of laser speckle imaging analysis in the spatial domain to quantify shifts in the microstructure of the tooth surface in an erosion model. 32 fragments of the vestibular surface of bovine incisors were divided in for groups (10 min, 20 min. 30 min and 40 min of acid etching immersed in a cola-based beverage (pH approximately 2.5 twice a day during 7 days to create an artificial erosion. By analyzing the laser speckle contrast map (LASCA in the eroded region compared to the sound it was observed that the LASCA map shifts, proportionally to the acid each duration, by: 18%; 23%; 39% and 44% for the 10 min; 20 min; 30 min and 40 min groups, respectively. To the best of our knowledge, this is the first study to demonstrate the correlation between speckle patterns and erosion progression.

An improved triangulation laser rangefinder using a custom CMOS HDR linear image sensor

Science.gov (United States)

Liscombe, Michael

3-D triangulation laser rangefinders are used in many modern applications, from terrain mapping to biometric identification. Although a wide variety of designs have been proposed, laser speckle noise still provides a fundamental limitation on range accuracy. These works propose a new triangulation laser rangefinder designed specifically to mitigate the effects of laser speckle noise. The proposed rangefinder uses a precision linear translator to laterally reposition the imaging system (e.g., image sensor and imaging lens). For a given spatial location of the laser spot, capturing N spatially uncorrelated laser spot profiles is shown to improve range accuracy by a factor of N . This technique has many advantages over past speckle-reduction technologies, such as a fixed system cost and form factor, and the ability to virtually eliminate laser speckle noise. These advantages are made possible through spatial diversity and come at the cost of increased acquisition time. The rangefinder makes use of the ICFYKWG1 linear image sensor, a custom CMOS sensor developed at the Vision Sensor Laboratory (York University). Tests are performed on the image sensor's innovative high dynamic range technology to determine its effects on range accuracy. As expected, experimental results have shown that the sensor provides a trade-off between dynamic range and range accuracy.

Laser-diode pumped Nd:YAG lasers; Laser diode reiki Nd:YAG lasear

Energy Technology Data Exchange (ETDEWEB)

Yuasa, H.; Akiyama, Y.; Nakayama, M. [Toshiba Corp., Tokyo (Japan)

2000-04-01

Laser-diode pumped Nd:YAG lasers are expected to be applied to laser processing fields such as welding, cutting, drilling, and marking due to their potential for high efficiency and compactness. We are designing and developing laser-diode pumped Nd:YAG lasers using numerical analysis simulation techniques such as ray tracing and thermal analysis. We have succeeded in achieving a laser power of more than 3 kW with 20% efficiency, which is the best ever obtained. In addition, we have developed a laser-diode pumped green laser by second harmonic generation, for precision machining on silicon wafers. (author)

Mode-selective mapping and control of vectorial nonlinear-optical processes in multimode photonic-crystal fibers.

Science.gov (United States)

Hu, Ming-Lie; Wang, Ching-Yue; Song, You-Jian; Li, Yan-Feng; Chai, Lu; Serebryannikov, Evgenii; Zheltikov, Aleksei

2006-02-06

We demonstrate an experimental technique that allows a mapping of vectorial nonlinear-optical processes in multimode photonic-crystal fibers (PCFs). Spatial and polarization modes of PCFs are selectively excited in this technique by varying the tilt angle of the input beam and rotating the polarization of the input field. Intensity spectra of the PCF output plotted as a function of the input field power and polarization then yield mode-resolved maps of nonlinear-optical interactions in multimode PCFs, facilitating the analysis and control of nonlinear-optical transformations of ultrashort laser pulses in such fibers.

Laser Materials Processing for NASA's Aerospace Structural Materials

Science.gov (United States)

Nagarathnam, Karthik; Hunyady, Thomas A.

2001-01-01

Lasers are useful for performing operations such as joining, machining, built-up freeform fabrication, and surface treatment. Due to the multifunctional nature of a single tool and the variety of materials that can be processed, these attributes are attractive in order to support long-term missions in space. However, current laser technology also has drawbacks for space-based applications. Specifically, size, power efficiency, lack of robustness, and problems processing highly reflective materials are all concerns. With the advent of recent breakthroughs in solidstate laser (e.g., diode-pumped lasers) and fiber optic technologies, the potential to perform multiple processing techniques in space has increased significantly. A review of the historical development of lasers from their infancy to the present will be used to show how these issues may be addressed. The review will also indicate where further development is necessary to realize a laser-based materials processing capability in space. The broad utility of laser beams in synthesizing various classes of engineering materials will be illustrated using state-of-the art processing maps for select lightweight alloys typically found on spacecraft. Both short- and long-term space missions will benefit from the development of a universal laser-based tool with low power consumption, improved process flexibility, compactness (e.g., miniaturization), robustness, and automation for maximum utility with a minimum of human interaction. The potential advantages of using lasers with suitable wavelength and beam properties for future space missions to the moon, Mars and beyond will be discussed. The laser processing experiments in the present report were performed using a diode pumped, pulsed/continuous wave Nd:YAG laser (50 W max average laser power), with a 1064 nm wavelength. The processed materials included Ti-6AI-4V, Al-2219 and Al-2090. For Phase I of this project, the laser process conditions were varied and optimized

Point-Cloud Compression for Vehicle-Based Mobile Mapping Systems Using Portable Network Graphics

Science.gov (United States)

Kohira, K.; Masuda, H.

2017-09-01

A mobile mapping system is effective for capturing dense point-clouds of roads and roadside objects Point-clouds of urban areas, residential areas, and arterial roads are useful for maintenance of infrastructure, map creation, and automatic driving. However, the data size of point-clouds measured in large areas is enormously large. A large storage capacity is required to store such point-clouds, and heavy loads will be taken on network if point-clouds are transferred through the network. Therefore, it is desirable to reduce data sizes of point-clouds without deterioration of quality. In this research, we propose a novel point-cloud compression method for vehicle-based mobile mapping systems. In our compression method, point-clouds are mapped onto 2D pixels using GPS time and the parameters of the laser scanner. Then, the images are encoded in the Portable Networking Graphics (PNG) format and compressed using the PNG algorithm. In our experiments, our method could efficiently compress point-clouds without deteriorating the quality.

POINT-CLOUD COMPRESSION FOR VEHICLE-BASED MOBILE MAPPING SYSTEMS USING PORTABLE NETWORK GRAPHICS

Directory of Open Access Journals (Sweden)

K. Kohira

2017-09-01

Full Text Available A mobile mapping system is effective for capturing dense point-clouds of roads and roadside objects．Point-clouds of urban areas, residential areas, and arterial roads are useful for maintenance of infrastructure, map creation, and automatic driving. However, the data size of point-clouds measured in large areas is enormously large. A large storage capacity is required to store such point-clouds, and heavy loads will be taken on network if point-clouds are transferred through the network. Therefore, it is desirable to reduce data sizes of point-clouds without deterioration of quality. In this research, we propose a novel point-cloud compression method for vehicle-based mobile mapping systems. In our compression method, point-clouds are mapped onto 2D pixels using GPS time and the parameters of the laser scanner. Then, the images are encoded in the Portable Networking Graphics (PNG format and compressed using the PNG algorithm. In our experiments, our method could efficiently compress point-clouds without deteriorating the quality.

A laser metrology/viewing system for ITER in-vessel inspection

International Nuclear Information System (INIS)

Spampinato, P.T.; Barry, R.E.; Chesser, J.B.; Herndon, J.N.; Menon, M.M.; Slotwinski, A.; Dagher, M.A.; Yuen, J.L.

1998-01-01

This paper identifies the requirements for the International Thermonuclear Experimental Reactor metrology and viewing system, and describes a remotely operated precision surface mapping system. A metrology system capable of achieving sub-millimeter accuracy must operate in a reactor vessel that has high gamma radiation, high vacuum, elevated temperature, and magnetic field. A coherent, frequency modulated laser radar system is under development to meet these requirements. The metrology/viewing sensor consists of a compact laser optics module linked through fiber optics to the laser source and imaging units, located outside the harsh environment. The deployment mechanism is a remotely operated telescopic-mast. Gamma irradiation to 10 7 Gy was conducted on critical sensor components at Oak Ridge National Laboratory, with no significant impact to data transmission, and analysis indicates that critical sensor components can operate in a magnetic field with certain design modifications. Plans for testing key components in a magnetic field are underway. (orig.)

Inverse Solutionof BP Neural Network for Laser Ｒemelting Parameters

Directory of Open Access Journals (Sweden)

LIU Li-jun

2017-06-01

Full Text Available Aim at highly nonlinear mapping relationship between the laser processing parameters and the melting cell body’s transverse size，a method of reverse engineering laser melting parameters by back － propagation ( BP neural network was put forward． The model was constructed by BP neural network，and the prediction error was reduced to less than 3% after training for many times． The DIEVAＲ die steel was melted by reverse engineering laser parameters，and the results show that the error was 1． 33% between the transverse dimensions of the melting cell body and the expected，the expected precision can be met well． Thermal fatigue property of the melted and non － melted DIEVAＲ die steel has been studied． The analysis about cracks growth presents that thermal fatigue property of DIEVAＲ die steel melted by the reverse engineering parameters has been greatly improved． The melting cell body could block crack effectively．

Laser light scattering in a laser-induced argon plasma: Investigations of the shock wave

Energy Technology Data Exchange (ETDEWEB)

Pokrzywka, B. [Obserwatorium Astronomiczne na Suhorze, Uniwersytet Pedagogiczny, ulica Podchorazych 2, 30-084 Krakow (Poland); Mendys, A., E-mail: agata.mendys@uj.edu.pl [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Dzierzega, K.; Grabiec, M. [Instytut Fizyki im. M. Smoluchowskiego, Uniwersytet Jagiellonski, ulica Reymonta 4, 30-059 Krakow (Poland); Pellerin, S. [GREMI, site de Bourges, Universite d' Orleans, CNRS, rue Gaston Berger BP 4043, 18028 Bourges (France)

2012-08-15

Shock wave produced by a laser induced spark in argon at atmospheric pressure was examined using Rayleigh and Thomson scattering. The spark was generated by focusing a laser pulse from the second harmonic ({lambda} = 532 nm) of a nanosecond Nd:YAG laser using an 80 mm focal length lens, with a fluence of 2 kJ{center_dot}cm{sup -2}. Images of the spark emission were recorded for times between 30 ns and 100 {mu}s after the laser pulse in order to characterize its spatial evolution. The position of the shock wave at several instants of its evolution and for several plasma regions was determined from the Rayleigh-scattered light of another nanosecond Nd:YAG laser (532 nm, 40 J{center_dot}cm{sup -2} fluence). Simultaneously, Thomson scattering technique was applied to determine the electron density and temperature in the hot plasma core. Attempts were made to describe the temporal evolution of the shock wave within a self-similar model, both by the simple Sedov-Taylor formula as well as its extension deduced by de Izarra. The temporal radial evolution of the shock position is similar to that obtained within theory taking into account the counter pressure of the ambient gas. Density profiles just behind the shock front are in qualitative agreement with those obtained by numerically solving the Euler equations for instantaneous explosion at a point with counter pressure. - Highlights: Black-Right-Pointing-Pointer We investigated shock wave evolution by Rayleigh scattering method. Black-Right-Pointing-Pointer 2D map of shockwave position for several times after plasma generation is presented. Black-Right-Pointing-Pointer Shock wave evolution is not satisfactorily described within self-similar models. Black-Right-Pointing-Pointer Evolution of shock position similar to theory taking into account counter pressure. Black-Right-Pointing-Pointer Density profile behind the shock similar to numerical solution of Euler equations.

Shock wave generation in laser ablation studied using pulsed digital holographic interferometry

Energy Technology Data Exchange (ETDEWEB)

Amer, Eynas; Gren, Per; Sjoedahl, Mikael [Division of Experimental Mechanics, Luleaa University of Technology, SE-971 87 Luleaa (Sweden)], E-mail: eynas.amer@ltu.se, E-mail: per.gren@ltu.se, E-mail: mikael.sjodahl@ltu.se

2008-11-07

Pulsed digital holographic interferometry has been used to study the shock wave induced by a Q-switched Nd-YAG laser ({lambda} = 1064 nm and pulse duration 12 ns) on a polycrystalline boron nitride (PCBN) ceramic target under atmospheric air pressure. A special setup based on using two synchronized wavelengths from the same laser for processing and measurement simultaneously has been introduced. Collimated laser light ({lambda} = 532 nm) passed through the volume along the target and digital holograms were recorded for different time delays after processing starts. Numerical data of the integrated refractive index field were calculated and presented as phase maps showing the propagation of the shock wave generated by the process. The location of the induced shock wave front was observed for different focusing and time delays. The amount of released energy, i.e. the part of the incident energy of the laser pulse that is eventually converted to a shock wave has been estimated using the point explosion model. The released energy is normalized by the incident laser pulse energy and the energy conversion efficiency between the laser pulse and PCBN target has been calculated at different power densities. The results show that the energy conversion efficiency seems to be constant around 80% at high power densities.

Study of the interaction between heavy ions and integrated circuits using a pulsed laser beam

International Nuclear Information System (INIS)

Lewis, D.; Fouillat, P.; Pouget, V.; Lapuyade, H.

2002-01-01

A new pulsed laser beam equipment dedicated to the characterization of integrated circuit is presented. Using ultra-short laser pulses is a convenient way to simulate experimentally the spatial environment of integrated circuits when interactions with heavy ions occur. This experimental set-up can be considered as a complementary tool for particle accelerators to evaluate the hardness assurance of integrated circuits for space applications. These particles generate temporally electrical disturbance called Single Event Effect (SEE). The theoretical approach of an equivalence between heavy ions and a laser pulses is discussed. The experimental set-up and some relevant operational methodologies are presented. Experimental results demonstrate that the induced electrical responses due to an heavy ion or a laser pulse are quite similar. Some sensitivity mappings of integrated circuits provided by this test bench illustrate the capabilities and the limitations of this laser-based technique. Contrary to the particle accelerators, it provides useful information concerning the spatial and temporal dependences of SEE mechanisms. (authors)

Expert-driven semi-automated geomorphological mapping for a mountainaous area using a laser DTM

NARCIS (Netherlands)

van Asselen, S.; Seijmonsbergen, A.C.

2006-01-01

n this paper a semi-automated method is presented to recognize and spatially delineate geomorphological units in mountainous forested ecosystems, using statistical information extracted from a 1-m resolution laser digital elevation dataset. The method was applied to a mountainous area in Austria.

Homoclinic crises in a model for the CO2 laser

International Nuclear Information System (INIS)

Pando L, C.L.; Cerdeira, H.A.

1993-04-01

We show that the four-level model for the CO 2 laser with modulated losses predicts a critical exponent close to 1/2 for the characteristic times in two homoclinic crises. In the five-dimensional Poincare map corresponding to this model, a sequential horseshoe formation due to the period three unstable orbit takes place after a region of multistability. (author). 14 refs, 4 figs

Microstructure and mechanical behavior of pulsed laser surface melted AISI D2 cold work tool steel

Science.gov (United States)

Yasavol, N.; Abdollah-zadeh, A.; Ganjali, M.; Alidokht, S. A.

2013-01-01

D2 cold work tool steel (CWTS) was subjected to pulse laser surface melting (PLSM) at constant frequency of 20 Hz Nd: YAG laser with different energies, scanning rate and pulse durations radiated to the surface. Characterizing the PLSM, with optical and field emission scanning electron microscopy, electron backscattered diffraction and surface hardness mapping technique was used to evaluate the microhardness and mechanical behavior of different regions of melting pool. Increasing laser energy and reducing the laser scanning rate results in deeper melt pool formation. Moreover, PLSM has led to entirely dissolution of the carbides and re-solidification of cellular/dendritic structure of a fine scale surrounded by a continuous interdendritic network. This caused an increase in surface microhardness, 2-4 times over that of the base metal.

Mapping Fearscapes of a Mammalian Herbivore using Terrestrial LiDAR and UAV Imagery

Science.gov (United States)

Olsoy, P.; Nobler, J. D.; Forbey, J.; Rachlow, J. L.; Burgess, M. A.; Glenn, N. F.; Shipley, L. A.

2013-12-01

Concealment allows prey animals to remain hidden from a predator and can influence both real and perceived risks of predation. The heterogeneous nature of vegetative structure can create a variable landscape of concealment - a 'fearscape' - that may influence habitat quality and use by prey. Traditional measurements of concealment rely on a limited number of distances, heights, and vantage points, resulting in small snapshots of concealment available to a prey animal. Our objective was to demonstrate the benefits of emerging remote sensing techniques to map fearscapes for pygmy rabbits (Brachylagus idahoensis) in sagebrush steppe habitat across a continuous range of scales. Specifically, we used vegetation height rasters derived from terrestrial laser scanning (TLS) to create viewsheds from multiple vantage points, representing predator visibility. The sum of all the viewsheds modeled horizontal concealment of prey at both the shrub and patch scales. We also used a small, unmanned aerial vehicle (UAV) to determine vertical concealment at a habitat scale. Terrestrial laser scanning provided similar estimates of horizontal concealment at the shrub scale when compared to photographic methods (R2 = 0.85). Both TLS and UAV provide the potential to quantify concealment of prey from multiple distances, heights, or vantage points, allowing the creation of a manipulable fearscape map that can be correlated with habitat use by prey animals. The predictive power of such a map also could identify shrubs or patches for fine scale nutritional and concealment analysis for future investigation and conservation efforts. Fearscape map at the mound-scale. Viewsheds were calculated from 100 equally spaced observer points located 4 m from the closest on-mound sagebrush of interest. Red areas offer low concealment, while green areas provide high concealment.

Stochastic sensitivity analysis of periodic attractors in non-autonomous nonlinear dynamical systems based on stroboscopic map

Energy Technology Data Exchange (ETDEWEB)

Guo, Kong-Ming, E-mail: kmguo@xidian.edu.cn [School of Electromechanical Engineering, Xidian University, P.O. Box 187, Xi' an 710071 (China); Jiang, Jun, E-mail: jun.jiang@mail.xjtu.edu.cn [State Key Laboratory for Strength and Vibration, Xi' an Jiaotong University, Xi' an 710049 (China)

2014-07-04

To apply stochastic sensitivity function method, which can estimate the probabilistic distribution of stochastic attractors, to non-autonomous dynamical systems, a 1/N-period stroboscopic map for a periodic motion is constructed in order to discretize the continuous cycle into a discrete one. In this way, the sensitivity analysis of a cycle for discrete map can be utilized and a numerical algorithm for the stochastic sensitivity analysis of periodic solutions of non-autonomous nonlinear dynamical systems under stochastic disturbances is devised. An external excited Duffing oscillator and a parametric excited laser system are studied as examples to show the validity of the proposed method. - Highlights: • A method to analyze sensitivity of stochastic periodic attractors in non-autonomous dynamical systems is proposed. • Probabilistic distribution around periodic attractors in an external excited Φ{sup 6} Duffing system is obtained. • Probabilistic distribution around a periodic attractor in a parametric excited laser system is determined.

Dynamics of bad-cavity-enhanced interaction with cold Sr atoms for laser stabilization

DEFF Research Database (Denmark)

Schäffer, S. A.; Christensen, B. T.R.; Henriksen, M. R.

2017-01-01

Hybrid systems of cold atoms and optical cavities are promising systems for increasing the stability of laser oscillators used in quantum metrology and atomic clocks. In this paper we map out the atom-cavity dynamics in such a system and demonstrate limitations as well as robustness of the approach....... We investigate the phase response of an ensemble of cold Sr88 atoms inside an optical cavity for use as an error signal in laser frequency stabilization. With this system we realize a regime where the high atomic phase shift limits the dynamical locking range. The limitation is caused by the cavity...

AERYN: A simple standalone application for visualizing and enhancing elemental maps

International Nuclear Information System (INIS)

Mouchi, Vincent; Crowley, Quentin G.; Ubide, Teresa

2016-01-01

Interpretation of high spatial resolution elemental mineral maps can be hindered by high frequency fluctuations, as well as by strong naturally-occurring or analytically-induced variations. We have developed a new standalone program named AERYN (Aspect Enhancement by Removing Yielded Noise) to produce more reliable element distribution maps from previously reduced geochemical data. The program is Matlab-based, designed with a graphic user interface and is capable of rapidly generating elemental maps from data acquired by a range of analytical techniques. A visual interface aids selection of appropriate outlier rejection and drift-correction parameters, thereby facilitating recognition of subtle elemental fluctuations which may otherwise be obscured. Examples of use are provided for quantitative trace element maps acquired using both laser ablation (LA-) ICP-MS and electron probe microanalysis (EPMA) of the cold-water coral Lophelia pertusa. We demonstrate how AERYN allows recognition of high frequency elemental fluctuations, including those which occur perpendicular to the maximum concentration gradient. Such data treatment compliments commonly used processing methods to provide greater flexibility and control in producing elemental maps from micro-analytical techniques. - Highlights: • Matlab-based application to improve visualization of elemental maps. • Capable of detrending when data set shows drift. • Compatible with processed data text files from LA-ICP-MS, EDS and EPMA. • Option to filter geochemical trends to observe high-frequency fluctuations.

SWATH label-free proteomics analyses revealed the roles of oxidative stress and antioxidant defensing system in sclerotia formation of Polyporus umbellatus

Science.gov (United States)

Li, Bing; Tian, Xiaofang; Wang, Chunlan; Zeng, Xu; Xing, Yongmei; Ling, Hong; Yin, Wanqiang; Tian, Lixia; Meng, Zhixia; Zhang, Jihui; Guo, Shunxing

2017-01-01

Understanding the initiation and maturing mechanisms is important for rational manipulating sclerotia differentiation and growth from hypha of Polyporus umbellatus. Proteomes in P. umbellatus sclerotia and hyphae at initial, developmental and mature phases were studied. 1391 proteins were identified by nano-liquid chromatograph-mass spectrometry (LC-MS) in Data Dependant Acquisition mode, and 1234 proteins were quantified successfully by Sequential Window Acquisition of all THeoretical fragment ion spectra-MS (SWATH-MS) technology. There were 347 differentially expressed proteins (DEPs) in sclerotia at initial phase compared with those in hypha, and the DEP profiles were dynamically changing with sclerotia growth. Oxidative stress (OS) in sclerotia at initial phase was indicated by the repressed proteins of respiratory chain, tricarboxylic acid cycle and the activation of glycolysis/gluconeogenesis pathways were determined based on DEPs. The impact of glycolysis/gluconeogenesis on sclerotium induction was further verified by glycerol addition assays, in which 5% glycerol significantly increased sclerotial differentiation rate and biomass. It can be speculated that OS played essential roles in triggering sclerotia differentiation from hypha of P. umbellatus, whereas antioxidant activity associated with glycolysis is critical for sclerotia growth. These findings reveal a mechanism for sclerotial differentiation in P. umbellatus, which may also be applicable for other fungi.

Using a terrestrial laser scanner to measure spatiotemporal surface moisture dynamics

Science.gov (United States)

Smit, Y.; Donker, J.; Ruessink, G.

2017-12-01

A terrestrial laser scanner (TLS) is an active remote sensing technique that utilizes the round trip time of an emitted laser beam to provide the range between the laser scanner and the backscattering object. It is routinely used for topographic mapping, forest measurements or 3D city models since it derives useful object representations by means of a dense three-dimensional (3D) point cloud. Here, we present a novel application using the returned intensity of the emitted beam to detect surface moisture with the RIEGL VZ-400. Because this TLS operates at a wavelength near a water absorption band (1550 nm), reflectance is an accurate parameter to measure surface moisture over its full range. Five days of intensive laser scanning were performed on a Dutch beach to illustrate the applicability of the TLS. Concurrent gravimetric surface moisture samples were collected to calibrate the relation between reflectance and surface moisture. Results reveal the reflectance output is a robust parameter to measure surface moisture from the thin upper layer over its full range from 0% to 25%. The obtained calibration curve of the presented TLS, describing the relationship between reflectance and surface moisture, has a root-mean-square error of 2.7% and a correlation coefficient squared of 0.85. This relation holds to about 60 m from the TLS. Within this distance the TLS typically produces O(10^6-10^7) data points, which we averaged into surface moisture maps with a 1 x 1 m resolution. This grid size largely removes small moisture disturbances induced by, for example, footprints or tire tracks, while retaining larger scale trends. Concluding, TLS (RIEGL-VZ 400) is a highly suited technique to accurately and robustly measure spatiotemporal surface moisture variations on a coastal beach with high spatial ( 1 x 1 m) and temporal ( 15-30min.) resolution.

Capability Assessment and Performance Metrics for the Titan Multispectral Mapping Lidar

Directory of Open Access Journals (Sweden)

Juan Carlos Fernandez-Diaz

2016-11-01

Full Text Available In this paper we present a description of a new multispectral airborne mapping light detection and ranging (lidar along with performance results obtained from two years of data collection and test campaigns. The Titan multiwave lidar is manufactured by Teledyne Optech Inc. (Toronto, ON, Canada and emits laser pulses in the 1550, 1064 and 532 nm wavelengths simultaneously through a single oscillating mirror scanner at pulse repetition frequencies (PRF that range from 50 to 300 kHz per wavelength (max combined PRF of 900 kHz. The Titan system can perform simultaneous mapping in terrestrial and very shallow water environments and its multispectral capability enables new applications, such as the production of false color active imagery derived from the lidar return intensities and the automated classification of target and land covers. Field tests and mapping projects performed over the past two years demonstrate capabilities to classify five land covers in urban environments with an accuracy of 90%, map bathymetry under more than 15 m of water, and map thick vegetation canopies at sub-meter vertical resolutions. In addition to its multispectral and performance characteristics, the Titan system is designed with several redundancies and diversity schemes that have proven to be beneficial for both operations and the improvement of data quality.

MOBILE MAPPING BY FMCW SYNTHETIC APERTURE RADAR OPERATING AT 300 GHZ

Directory of Open Access Journals (Sweden)

S. Palm

2016-06-01

Full Text Available While optical cameras or laser systems are widely used for mobile mapping low attention was payed for radar systems. Due to new semiconductor technologies, compact and leight weight SAR systems based on the Frequency Modulated Continuous Wave (FMCW principle in the millimeter wave domain can serve for mobile radar mapping on cars. For mapping of long stripes along roads in close range a special strategy for focusing of SAR images was developed. Hereby local adapted planes for processing are used considering the IMU data of the sensor. An experimental system was designed for high resolution radar mapping of urban scenes in close range geometry. This small and leight weighted system has a bandwidth of 30 GHz (5 mm resolution and operates with 300 GHz in the lower terahertz domain. Experiments with a van in an urban scenario were carried out for proof of applicability of an operating SAR system resolving objects in the subcentimeter domain. The results show that narrow cracks in the asphalt of the road are visible and the measuring of small metallic objects placed in the scene is possible. Based on this mobile mapping techniques a first result from an acquisition of vertical facade structure is shown.

Lasers '89

International Nuclear Information System (INIS)

Harris, D.G.; Shay, T.M.

1990-01-01

This book covers the following topics: XUV, X-Ray and Gamma-Ray Lasers, excimer lasers, chemical lasers, nuclear pumped lasers, high power gas lasers, solid state lasers, laser spectroscopy. The paper presented include: Development of KrF lasers for fusion and Nuclear driven solid-state lasers

3D Lasers Increase Efficiency, Safety of Moving Machines

Science.gov (United States)

2015-01-01

Canadian company Neptec Design Group Ltd. developed its Laser Camera System, used by shuttles to render 3D maps of their hulls for assessing potential damage. Using NASA funding, the firm incorporated LiDAR technology and created the TriDAR 3D sensor. Its commercial arm, Neptec Technologies Corp., has sold the technology to Orbital Sciences, which uses it to guide its Cygnus spacecraft during rendezvous and dock operations at the International Space Station.

Enface Thickness Mapping and Reflectance Imaging of Retinal Layers in Diabetic Retinopathy.

Science.gov (United States)

Francis, Andrew W; Wanek, Justin; Lim, Jennifer I; Shahidi, Mahnaz

2015-01-01

To present a method for image segmentation and generation of enface thickness maps and reflectance images of retinal layers in healthy and diabetic retinopathy (DR) subjects. High density spectral domain optical coherence tomography (SDOCT) images were acquired in 10 healthy and 4 DR subjects. Customized image analysis software identified 5 retinal cell layer interfaces and generated thickness maps and reflectance images of the total retina (TR), inner retina (IR), outer retina (OR), and the inner segment ellipsoid (ISe) band. Thickness maps in DR subjects were compared to those of healthy subjects by generating deviation maps which displayed retinal locations with thickness below, within, and above the normal 95% confidence interval. In healthy subjects, TR and IR thickness maps displayed the foveal depression and increased thickness in the parafoveal region. OR and ISe thickness maps showed increased thickness at the fovea, consistent with normal retinal anatomy. In DR subjects, thickening and thinning in localized regions were demonstrated on TR, IR, OR, and ISe thickness maps, corresponding to retinal edema and atrophy, respectively. TR and OR reflectance images showed reduced reflectivity in regions of increased thickness. Hard exudates appeared as hyper-reflective spots in IR reflectance images and casted shadows on the deeper OR and ISe reflectance images. The ISe reflectance image clearly showed the presence of focal laser scars. Enface thickness mapping and reflectance imaging of retinal layers is a potentially useful method for quantifying the spatial and axial extent of pathologies due to DR.

Rapid tryptic mapping using enzymatically active mass spectrometer probe tips

Energy Technology Data Exchange (ETDEWEB)

Dogruel, D.; Williams, P.; Nelson, R.W. [Arizona State Univ., Tempe, AZ (United States)

1995-12-01

A method has been developed for rapid, sensitive, and accurate tryptic mapping of polypeptides using matrix-assisted laser desorption/ionization time-of-flight mass analysis. The technique utilizes mass spectrometer probe tips which have been activated through the covalent immobilization of trypsin. The enzymatically active probe tips were used for the tryptic mapping of chicken egg lysozyme and the results compared with those obtained using either free trypsin or agarose-immobilized trypsin. A significant increase in the overall sensitivity of the process was observed using the active probe tips, as well as the production of more characteristic proteolytic fragments and the elimination of background signals due to the autolysis of the trypsin. Further, probe tip digestions were found to be rapid and convenient. 19 refs., 6 figs., 2 tabs.

Comprehensive experimental analysis of nonlinear dynamics in an optically-injected semiconductor laser

Directory of Open Access Journals (Sweden)

Kevin Schires

2011-09-01

Full Text Available We present the first comprehensive experimental study, to our knowledge, of the routes between nonlinear dynamics induced in a semiconductor laser under external optical injection based on an analysis of time-averaged measurements of the optical and RF spectra and phasors of real-time series of the laser output. The different means of analysis are compared for several types of routes and the benefits of each are discussed in terms of the identification and mapping of the nonlinear dynamics. Finally, the results are presented in a novel audio/video format that describes the evolution of the dynamics with the injection parameters.

Laser-induced plasma spectrometry: truly a surface analytical tool

International Nuclear Information System (INIS)

Vadillo, Jose M.; Laserna, J.

2004-01-01

For a long period, analytical applications of laser induced plasma spectrometry (LIPS) have been mainly restricted to overall and quantitative determination of elemental composition in bulk, solid samples. However, introduction of new compact and reliable solid state lasers and technological development in multidimensional intensified detectors have made possible the seeking of new analytical niches for LIPS where its analytical advantages (direct sampling from any material irrespective of its conductive status without sample preparation and with sensitivity adequate for many elements in different matrices) could be fully exploited. In this sense, the field of surface analysis could take advantage from the cited advantages taking into account in addition, the capability of LIPS for spot analysis, line scan, depth-profiling, area analysis and compositional mapping with a single instrument in air at atmospheric pressure. This review paper outlines the fundamental principles of laser-induced plasma emission relevant to sample surface studies, discusses the experimental parameters governing the spatial (lateral and in-depth) resolution in LIPS analysis and presents the applications concerning surface examination

Multiplatform Mobile Laser Scanning: Usability and Performance

Directory of Open Access Journals (Sweden)

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 safety at high profile laser facilities

International Nuclear Information System (INIS)

Barat, K.

2010-01-01

Complete text of publication follows. Laser safety has been an active concern of laser users since the invention of the laser. Formal standards were developed in the early 1970's and still continue to be developed and refined. The goal of these standards is to give users guidance on the use of laser and consistent safety guidance and requirements for laser manufacturers. Laser safety in the typical research setting (government laboratory or university) is the greatest challenge to the laser user and laser safety officer. This is due to two factors. First, the very nature of research can put the user at risk; consider active manipulation of laser optics and beam paths, and user work with energized systems. Second, a laser safety culture that seems to accept laser injuries as part of the graduate student educational process. The fact is, laser safety at research settings, laboratories and universities still has long way to go. Major laser facilities have taken a more rigid and serious view of laser safety, its controls and procedures. Part of the rationale for this is that these facilities draw users from all around the world presenting the facility with a work force of users coming from a wide mix of laser safety cultures. Another factor is funding sources do not like bad publicity which can come from laser accidents and a poor safety record. The fact is that injuries, equipment damage and lost staff time slow down progress. Hence high profile/large laser projects need to adapt a higher safety regimen both from an engineering and administrative point of view. This presentation will discuss all these points and present examples. Acknowledgement. This work has been supported by the University of California, Director, Office of Science.

A voting-based statistical cylinder detection framework applied to fallen tree mapping in terrestrial laser scanning point clouds

Science.gov (United States)

Polewski, Przemyslaw; Yao, Wei; Heurich, Marco; Krzystek, Peter; Stilla, Uwe

2017-07-01

This paper introduces a statistical framework for detecting cylindrical shapes in dense point clouds. We target the application of mapping fallen trees in datasets obtained through terrestrial laser scanning. This is a challenging task due to the presence of ground vegetation, standing trees, DTM artifacts, as well as the fragmentation of dead trees into non-collinear segments. Our method shares the concept of voting in parameter space with the generalized Hough transform, however two of its significant drawbacks are improved upon. First, the need to generate samples on the shape's surface is eliminated. Instead, pairs of nearby input points lying on the surface cast a vote for the cylinder's parameters based on the intrinsic geometric properties of cylindrical shapes. Second, no discretization of the parameter space is required: the voting is carried out in continuous space by means of constructing a kernel density estimator and obtaining its local maxima, using automatic, data-driven kernel bandwidth selection. Furthermore, we show how the detected cylindrical primitives can be efficiently merged to obtain object-level (entire tree) semantic information using graph-cut segmentation and a tailored dynamic algorithm for eliminating cylinder redundancy. Experiments were performed on 3 plots from the Bavarian Forest National Park, with ground truth obtained through visual inspection of the point clouds. It was found that relative to sample consensus (SAC) cylinder fitting, the proposed voting framework can improve the detection completeness by up to 10 percentage points while maintaining the correctness rate.

A hybrid CATV/16-QAM-OFDM visible laser light communication system

International Nuclear Information System (INIS)

Lin, Chun-Yu; Li, Chung-Yi; Lu, Hai-Han; Chen, Chia-Yi; Jhang, Tai-Wei; Ruan, Sheng-Siang; Wu, Kuan-Hung

2014-01-01

A visible laser light communication (VLLC) system employing a vertical cavity surface emitting laser and spatial light modulator with hybrid CATV/16-QAM-OFDM modulating signals over a 5 m free-space link is proposed and demonstrated. With the assistance of a push-pull scheme, low-noise amplifier, and equalizer, good performances of composite second-order and composite triple beat are obtained, accompanied by an acceptable carrier-to-noise ratio performance for a CATV signal, and a low bit error rate value and clear constellation map are achieved for a 16-QAM-OFDM signal. Such a hybrid CATV/16-QAM-OFDM VLLC system would be attractive for providing services including CATV, Internet and telecommunication services. (paper)

Learning probabilistic features for robotic navigation using laser sensors.

Directory of Open Access Journals (Sweden)

Fidel Aznar

Full Text Available SLAM is a popular task used by robots and autonomous vehicles to build a map of an unknown environment and, at the same time, to determine their location within the map. This paper describes a SLAM-based, probabilistic robotic system able to learn the essential features of different parts of its environment. Some previous SLAM implementations had computational complexities ranging from O(Nlog(N to O(N(2, where N is the number of map features. Unlike these methods, our approach reduces the computational complexity to O(N by using a model to fuse the information from the sensors after applying the Bayesian paradigm. Once the training process is completed, the robot identifies and locates those areas that potentially match the sections that have been previously learned. After the training, the robot navigates and extracts a three-dimensional map of the environment using a single laser sensor. Thus, it perceives different sections of its world. In addition, in order to make our system able to be used in a low-cost robot, low-complexity algorithms that can be easily implemented on embedded processors or microcontrollers are used.

Learning probabilistic features for robotic navigation using laser sensors.

Science.gov (United States)

Aznar, Fidel; Pujol, Francisco A; Pujol, Mar; Rizo, Ramón; Pujol, María-José

2014-01-01

SLAM is a popular task used by robots and autonomous vehicles to build a map of an unknown environment and, at the same time, to determine their location within the map. This paper describes a SLAM-based, probabilistic robotic system able to learn the essential features of different parts of its environment. Some previous SLAM implementations had computational complexities ranging from O(Nlog(N)) to O(N(2)), where N is the number of map features. Unlike these methods, our approach reduces the computational complexity to O(N) by using a model to fuse the information from the sensors after applying the Bayesian paradigm. Once the training process is completed, the robot identifies and locates those areas that potentially match the sections that have been previously learned. After the training, the robot navigates and extracts a three-dimensional map of the environment using a single laser sensor. Thus, it perceives different sections of its world. In addition, in order to make our system able to be used in a low-cost robot, low-complexity algorithms that can be easily implemented on embedded processors or microcontrollers are used.

The use of airborne laser data to calibrate satellite radar altimetry data over ice sheets

DEFF Research Database (Denmark)

Ekholm, Simon; Bamber, J.L.; Krabill, W.B.

2002-01-01

Satellite radar altimetry is the most important data source for ice sheet elevation modeling but it is well established that the accuracy of such data from satellite borne radar altimeters degrade seriously with increasing surface slope and level of roughness. A significant fraction of the slope......-precision airborne laser profiling data from the so-called Arctic Ice Mapping project as a tool to determine that bias and to calibrate the satellite altimetry. This is achieved by a simple statistical analysis of the airborne laser profiles, which defines the mean amplitude of the local surface undulations...

Swath-altimetry measurements of the main stem Amazon River: measurement errors and hydraulic implications

Science.gov (United States)

Wilson, M. D.; Durand, M.; Jung, H. C.; Alsdorf, D.

2015-04-01

The Surface Water and Ocean Topography (SWOT) mission, scheduled for launch in 2020, will provide a step-change improvement in the measurement of terrestrial surface-water storage and dynamics. In particular, it will provide the first, routine two-dimensional measurements of water-surface elevations. In this paper, we aimed to (i) characterise and illustrate in two dimensions the errors which may be found in SWOT swath measurements of terrestrial surface water, (ii) simulate the spatio-temporal sampling scheme of SWOT for the Amazon, and (iii) assess the impact of each of these on estimates of water-surface slope and river discharge which may be obtained from SWOT imagery. We based our analysis on a virtual mission for a ~260 km reach of the central Amazon (Solimões) River, using a hydraulic model to provide water-surface elevations according to SWOT spatio-temporal sampling to which errors were added based on a two-dimensional height error spectrum derived from the SWOT design requirements. We thereby obtained water-surface elevation measurements for the Amazon main stem as may be observed by SWOT. Using these measurements, we derived estimates of river slope and discharge and compared them to those obtained directly from the hydraulic model. We found that cross-channel and along-reach averaging of SWOT measurements using reach lengths greater than 4 km for the Solimões and 7.5 km for Purus reduced the effect of systematic height errors, enabling discharge to be reproduced accurately from the water height, assuming known bathymetry and friction. Using cross-sectional averaging and 20 km reach lengths, results show Nash-Sutcliffe model efficiency values of 0.99 for the Solimões and 0.88 for the Purus, with 2.6 and 19.1 % average overall error in discharge, respectively. We extend the results to other rivers worldwide and infer that SWOT-derived discharge estimates may be more accurate for rivers with larger channel widths (permitting a greater level of cross

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.

Investigation of the osteitis deformans phases in snake vertebrae by double-pulse laser-induced breakdown spectroscopy

Czech Academy of Sciences Publication Activity Database

Galiová, M.; Kaiser, J.; Novotný, K.; Ivanov, M.; Nývltová Fišáková, Miriam; Mancini, L.; Tromba, G.; Vaculovič, T.; Liška, M.; Kanický, V.

2010-01-01

Roč. 398, č. 2 (2010), s. 1095-1107 ISSN 1618-2642 Institutional research plan: CEZ:AV0Z80010507 Keywords : laser ablation * LIBS * Mapping * X-ray * microtomography * fossil * snake * vertebrates Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 3.841, year: 2010

Measurement of electromagnetic pulses generated during interactions of high power lasers with solid targets

International Nuclear Information System (INIS)

De Marco, M.; Krása, J.; Margarone, D.; Giuffrida, L.; Vrana, R.; Velyhan, A.; Korn, G.; Weber, S.; Cikhardt, J.; Pfeifer, M.; Krouský, E.; Ullschmied, J.; Ahmed, H.; Borghesi, M.; Kar, S.; Limpouch, J.; Velardi, L.; Side, D. Delle; Nassisi, V.

2016-01-01

A target irradiated with a high power laser pulse, blows off a large amount of charge and as a consequence the target itself becomes a generator of electromagnetic pulses (EMP) owing to high return current flowing to the ground through the target holder. The first measurement of the magnetic field induced by the neutralizing current reaching a value of a few kA was performed with the use of an inductive target probe at the PALS Laser Facility (Cikhardt et al. Rev. Sci. Instrum. 85 (2014) 103507). A full description of EMP generation should contain information on the spatial distribution and temporal variation of the electromagnetic field inside and outside of the interaction chamber. For this reason, we consider the interaction chamber as a resonant cavity in which different modes of EMP oscillate for hundreds of nanoseconds, until the EMP is transmitted outside through the glass windows and EM waves are attenuated. Since the experimental determination of the electromagnetic field distribution is limited by the number of employed antennas, a mapping of the electromagnetic field has to be integrated with numerical simulations. Thus, this work reports on a detailed numerical mapping of the electromagnetic field inside the interaction chamber at the PALS Laser Facility (covering a frequency spectrum from 100 MHz to 3 GHz) using the commercial code COMSOL Multiphysics 5.2. Moreover we carried out a comparison of the EMP generated in the parallelepiped-like interaction chamber used in the Vulcan Petawatt Laser Facility at the Rutherford Appleton Laboratory, against that produced in the spherical interaction chamber of PALS.

Fibre-optic laser-assisted infrared tumour diagnostics (FLAIR)

Science.gov (United States)

Bindig, U.; Müller, G.

2005-08-01

Laser based fibre-optic surgery procedures are commonly used in minimal invasive surgery. Despite the development of precise and efficient laser systems there are also innovative attempts in the field of bio-medical diagnostics. As a direct result of the tissue's optical properties most applications are focused on the visible wavelength range of the spectrum. The extension of the spectrum up to the mid-infrared (IR) region will offer a broad range of possibilities for novel strategies with a view to non-invasive diagnostics in medicine. We describe a method to detect differences between diseased and normal tissues, which involve Fourier transform IR microspectroscopy and fibre-optics methods. Regions of interest on 10 µm thin tissue sections were mapped using an IR microscope in transmission mode. After IR-mapping, the samples were analysed using standard pathological techniques. Quadratic discriminant and correlation analyses were applied to the IR maps obtained allowing differentiation between cancerous and normal tissue. The use of optical fibres, transparent in the mid-IR, allowed measurements to be made in the attenuated total reflectance (ATR)-mode at a remote location. The IR sensor is in contact with the sample that shows characteristic absorption lines. The total transmission of the fibre and the sample will decrease at these lines. This method can be used to determine the absorption of a sample in a non-destructive manner. In this paper we report on our efforts to develop an IR fibre-optic sensor for tissue identification as well as to differentiate between malignant and healthy tissue in vivo. We also describe the technical design of the laboratory set-up and the results of developments made. Silver halide fibres and a special sensor tip were used for the ATR measurements on tissue specimens. The results indicate that fibre-optic IR spectrometry will be a useful tool for bio-diagnostics.

Fibre-optic laser-assisted infrared tumour diagnostics (FLAIR)

International Nuclear Information System (INIS)

Bindig, U; Mueller, G

2005-01-01

Laser based fibre-optic surgery procedures are commonly used in minimal invasive surgery. Despite the development of precise and efficient laser systems there are also innovative attempts in the field of bio-medical diagnostics. As a direct result of the tissue's optical properties most applications are focused on the visible wavelength range of the spectrum. The extension of the spectrum up to the mid-infrared (IR) region will offer a broad range of possibilities for novel strategies with a view to non-invasive diagnostics in medicine. We describe a method to detect differences between diseased and normal tissues, which involve Fourier transform IR microspectroscopy and fibre-optics methods. Regions of interest on 10 μm thin tissue sections were mapped using an IR microscope in transmission mode. After IR-mapping, the samples were analysed using standard pathological techniques. Quadratic discriminant and correlation analyses were applied to the IR maps obtained allowing differentiation between cancerous and normal tissue. The use of optical fibres, transparent in the mid-IR, allowed measurements to be made in the attenuated total reflectance (ATR)-mode at a remote location. The IR sensor is in contact with the sample that shows characteristic absorption lines. The total transmission of the fibre and the sample will decrease at these lines. This method can be used to determine the absorption of a sample in a non-destructive manner. In this paper we report on our efforts to develop an IR fibre-optic sensor for tissue identification as well as to differentiate between malignant and healthy tissue in vivo. We also describe the technical design of the laboratory set-up and the results of developments made. Silver halide fibres and a special sensor tip were used for the ATR measurements on tissue specimens. The results indicate that fibre-optic IR spectrometry will be a useful tool for bio-diagnostics

Tip-enhanced Raman mapping with top-illumination AFM.

Science.gov (United States)

Chan, K L Andrew; Kazarian, Sergei G

2011-04-29

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

Tip-enhanced Raman mapping with top-illumination AFM

Energy Technology Data Exchange (ETDEWEB)

Chan, K L Andrew; Kazarian, Sergei G, E-mail: s.kazarian@imperial.ac.uk [Department of Chemical Engineering, Imperial College London, SW7 2AZ (United Kingdom)

2011-04-29

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of {approx} 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

Tip-enhanced Raman mapping with top-illumination AFM

International Nuclear Information System (INIS)

Chan, K L Andrew; Kazarian, Sergei G

2011-01-01

Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

Large area optical mapping of surface contact angle.

Science.gov (United States)

Dutra, Guilherme; Canning, John; Padden, Whayne; Martelli, Cicero; Dligatch, Svetlana

2017-09-04

Top-down contact angle measurements have been validated and confirmed to be as good if not more reliable than side-based measurements. A range of samples, including industrially relevant materials for roofing and printing, has been compared. Using the top-down approach, mapping in both 1-D and 2-D has been demonstrated. The method was applied to study the change in contact angle as a function of change in silver (Ag) nanoparticle size controlled by thermal evaporation. Large area mapping reveals good uniformity for commercial Aspen paper coated with black laser printer ink. A demonstration of the forensic and chemical analysis potential in 2-D is shown by uncovering the hidden CsF initials made with mineral oil on the coated Aspen paper. The method promises to revolutionize nanoscale characterization and industrial monitoring as well as chemical analyses by allowing rapid contact angle measurements over large areas or large numbers of samples in ways and times that have not been possible before.

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

Directory of Open Access Journals (Sweden)

Bakuła Krzysztof

2015-12-01

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

Self-oscillations in cw solid-state ultrashort-pulse-generating lasers with mode locking by self-focusing

International Nuclear Information System (INIS)

Kalashnikov, V L; Krimer, D O; Mejid, F; Poloiko, I G; Mikhailov, V P

1999-01-01

Steady-state and transient regimes of ultrashort pulse generation are studied for cw solid-state lasers with mode locking by self-focusing. It is shown that the control parameter, which governs the nature of lasing, is the relationship between self-phase-modulation and the saturation intensity of an efficient shutter, induced by the Kerr self-focusing. Numerical modelling based on mapping the parameters of a quasi-soliton ultrashort pulse, considered in the aberration-free approximation, yields results in good agreement with experiments. (control of laser radiation parameters)

Laser in urology. Laser i urologien

Energy Technology Data Exchange (ETDEWEB)

Breisland, H.O. (Aker Sykehus, Oslo (Norway))

1991-09-01

The neodymium YAG laser is particularly suited for endoscopic urologic surgery because the YAG laser light can be conducted in flexible fibers. Superficial bladder tumours can be treated under local anaesthesia in the outpatient department. The frequency of local recurrences is low, significantly lower than after electrosection or electrocoagulation. Selected cases of T2-muscle invasive bladder tumours can be cured with laser coagulation applied subsequently to transurethral resection. Combined treatment with electrosection and laser coagulation of localized prostatic cancer is a promising method which compares favourably with results obtained by other treatment modalities. Tumours in the upper urinary tract can be laser-treated through ureteroscopes or nephroscopes, but the treatment should be limited to low stage, low grade tumours. Laser is the treatment of choice for intraurethral condylomatas. Laser treatment of penil carcinoma gives excellent cosmetic and functional results and few local recurrences. Laser lithotripsy is a new technique for treatment of ureteric stones and photodynamic laser therapy is a promising tecnique for treatment of carcinoma in situ in the bladder empithelium. However, neither of these techniques are available for clinical use in Norway as yet. 17 refs., 3 figs., 1 tabs.

A monolithic relativistic electron beam source based on a dielectric laser accelerator structure

International Nuclear Information System (INIS)

McNeur, Josh; Carranza, Nestor; Travish, Gil; Yin Hairong; Yoder, Rodney

2012-01-01

Work towards a monolithic device capable of producing relativistic particle beams within a cubic-centimeter is detailed. We will discuss the Micro-Accelerator Platform (MAP), an optical laser powered dielectric accelerator as the main building block of this chip-scale source along with a field enhanced emitter and a region for sub-relativistic acceleration.

New developments in laser-based photoemission spectroscopy and its scientific applications: a key issues review

Science.gov (United States)

Zhou, Xingjiang; He, Shaolong; Liu, Guodong; Zhao, Lin; Yu, Li; Zhang, Wentao

2018-06-01

The significant progress in angle-resolved photoemission spectroscopy (ARPES) in last three decades has elevated it from a traditional band mapping tool to a precise probe of many-body interactions and dynamics of quasiparticles in complex quantum systems. The recent developments of deep ultraviolet (DUV, including ultraviolet and vacuum ultraviolet) laser-based ARPES have further pushed this technique to a new level. In this paper, we review some latest developments in DUV laser-based photoemission systems, including the super-high energy and momentum resolution ARPES, the spin-resolved ARPES, the time-of-flight ARPES, and the time-resolved ARPES. We also highlight some scientific applications in the study of electronic structure in unconventional superconductors and topological materials using these state-of-the-art DUV laser-based ARPES. Finally we provide our perspectives on the future directions in the development of laser-based photoemission systems.

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

Directory of Open Access Journals (Sweden)

R. A. Kuçak

2016-10-01

Full Text Available Historical artifacts living from the past until today exposed to many destructions non-naturally or naturally. For this reason, The protection and documentation studies of Cultural Heritage to inform the next generations are accelerating day by day in the whole world. The preservation of historical artifacts using advanced 3D measurement technologies becomes an efficient tool for mapping solutions. There are many methods for documentation and restoration of historic structures. In addition to traditional methods such as simple hand measurement and tachometry, terrestrial laser scanning is rapidly becoming one of the most commonly used techniques due to its completeness, accuracy and fastness characteristics. This study evaluates terrestrial laser scanning(TLS technology and photogrammetry for documenting the historical artifacts facade data in 3D Environment. PhotoModeler software developed by Eos System was preferred for Photogrammetric method. Leica HDS 6000 laser scanner developed by Leica Geosystems and Cyclone software which is the laser data evaluation software belonging to the company is preferred for Terrestrial Laser Scanning method. Taking into account the results obtained with this software product is intended to provide a contribution to the studies for the documentation of cultural heritage.

Three main paradigms of simultaneous localization and mapping (SLAM) problem

Science.gov (United States)

Imani, Vandad; Haataja, Keijo; Toivanen, Pekka

2018-04-01

Simultaneous Localization and Mapping (SLAM) is one of the most challenging research areas within computer and machine vision for automated scene commentary and explanation. The SLAM technique has been a developing research area in the robotics context during recent years. By utilizing the SLAM method robot can estimate the different positions of the robot at the distinct points of time which can indicate the trajectory of robot as well as generate a map of the environment. SLAM has unique traits which are estimating the location of robot and building a map in the various types of environment. SLAM is effective in different types of environment such as indoor, outdoor district, Air, Underwater, Underground and Space. Several approaches have been investigated to use SLAM technique in distinct environments. The purpose of this paper is to provide an accurate perceptive review of case history of SLAM relied on laser/ultrasonic sensors and camera as perception input data. In addition, we mainly focus on three paradigms of SLAM problem with all its pros and cons. In the future, use intelligent methods and some new idea will be used on visual SLAM to estimate the motion intelligent underwater robot and building a feature map of marine environment.

An Approach of Dynamic Object Removing for Indoor Mapping Based on UGV SLAM

Directory of Open Access Journals (Sweden)

Jian Tang

2015-07-01

Full Text Available The study of indoor mapping for Location Based Service (LBS becomes more and more popular in recent years. LiDAR SLAM based mapping method seems to be a promising indoor mapping solution. However, there are some dynamic objects such as pedestrians, indoor vehicles, etc. existing in the raw LiDAR range data. They have to be removal for mapping purpose. In this paper, a new approach of dynamic object removing called Likelihood Grid Voting (LGV is presented. It is a model free method and takes full advantage of the high scanning rate of LiDAR, which is moving at a relative low speed in indoor environment. In this method, a counting grid is allocated for recording the occupation of map position by laser scans. The lower counter value of this position can be recognized as dynamic objects and the point cloud will be removed from map. This work is a part of algorithms in our self- developed Unmanned Ground Vehicles (UGV simultaneous localization and Mapping (SLAM system- NAVIS. Field tests are carried in an indoor parking place with NAVIS to evaluate the effectiveness of the proposed method. The result shows that all the small size objects like pedestrians can be detected and removed quickly; large size of objects like cars can be detected and removed partly.

Classification of Mobile Laser Scanning Point Clouds from Height Features

Science.gov (United States)

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

2017-09-01

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

California State Waters Map Series: offshore of San Gregorio, California

Science.gov (United States)

Cochrane, Guy R.; Dartnell, Peter; Greene, H. Gary; Watt, Janet T.; Golden, Nadine E.; Endris, Charles A.; Phillips, Eleyne L.; Hartwell, Stephen R.; Johnson, Samuel Y.; Kvitek, Rikk G.; Erdey, Mercedes D.; Bretz, Carrie K.; Manson, Michael W.; Sliter, Ray W.; Ross, Stephanie L.; Dieter, Bryan E.; Chin, John L.; Cochran, Susan A.; Cochrane, Guy R.; Cochran, Susan A.

2014-01-01

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California's State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of San Gregorio map area is located in northern California, on the Pacific coast of the San Francisco Peninsula about 50 kilometers south of the Golden Gate. The map area lies offshore of the Santa Cruz Mountains, part of the northwest-trending Coast Ranges that run roughly parallel to the San Andreas Fault Zone. The Santa Cruz Mountains lie between the San Andreas Fault Zone and the San Gregorio Fault system. The nearest significant onshore cultural centers in the map area are San Gregorio and Pescadero, both unincorporated communities with populations well under 1,000. Both communities are situated inland of state beaches that share their names. No harbor facilities are within the Offshore of San Gregorio map area. The hilly coastal area is virtually undeveloped grazing land for sheep and cattle. The coastal geomorphology is controlled by late Pleistocene and Holocene slip in the San Gregorio Fault system. A westward bend in the San Andreas Fault Zone, southeast of the map area, coupled with right-lateral movement along the San Gregorio Fault system have caused regional folding and uplift. The coastal area consists of high coastal bluffs and vertical sea cliffs. Coastal promontories in

Landslides Mapped from LIDAR Imagery, Kitsap County, Washington

Science.gov (United States)

McKenna, Jonathan P.; Lidke, David J.; Coe, Jeffrey A.

2008-01-01

Landslides are a recurring problem on hillslopes throughout the Puget Lowland, Washington, but can be difficult to identify in the densely forested terrain. However, digital terrain models of the bare-earth surface derived from LIght Detection And Ranging (LIDAR) data express topographic details sufficiently well to identify landslides. Landslides and escarpments were mapped using LIDAR imagery and field checked (when permissible and accessible) throughout Kitsap County. We relied almost entirely on derivatives of LIDAR data for our mapping, including topographic-contour, slope, and hill-shaded relief maps. Each mapped landslide was assigned a level of 'high' or 'moderate' confidence based on the LIDAR characteristics and on field observations. A total of 231 landslides were identified representing 0.8 percent of the land area of Kitsap County. Shallow debris topples along the coastal bluffs and large (>10,000 m2) landslide complexes are the most common types of landslides. The smallest deposit mapped covers an area of 252 m2, while the largest covers 0.5 km2. Previous mapping efforts that relied solely on field and photogrammetric methods identified only 57 percent of the landslides mapped by LIDAR (61 percent high confidence and 39 percent moderate confidence), although nine landslides previously identified were not mapped during this study. The remaining 43 percent identified using LIDAR have 13 percent high confidence and 87 percent moderate confidence. Coastal areas are especially susceptible to landsliding; 67 percent of the landslide area that we mapped lies within 500 meters of the present coastline. The remaining 33 percent are located along drainages farther inland. The LIDAR data we used for mapping have some limitations including (1) rounding of the interface area between low slope surfaces and vertical faces (that is, along the edges of steep escarpments) which results in scarps being mapped too far headward (one or two meters), (2) incorrect laser

First result on biased CMOS MAPs-on-diamond devices

Energy Technology Data Exchange (ETDEWEB)

Kanxheri, K., E-mail: keida.kanxheri@pg.infn.it [Università degli Studi di Perugia, Perugia (Italy); INFN Perugia, Perugia (Italy); Citroni, M.; Fanetti, S. [LENS Firenze, Florence (Italy); Lagomarsino, S. [Università degli Studi di Firenze, Florence (Italy); INFN Firenze, Pisa (Italy); Morozzi, A. [Università degli Studi di Perugia, Perugia (Italy); INFN Perugia, Perugia (Italy); Parrini, G. [Università degli Studi di Firenze, Florence (Italy); Passeri, D. [Università degli Studi di Perugia, Perugia (Italy); INFN Perugia, Perugia (Italy); Sciortino, S. [Università degli Studi di Firenze, Florence (Italy); INFN Firenze, Pisa (Italy); Servoli, L. [INFN Perugia, Perugia (Italy)

2015-10-01

Recently a new type of device, the MAPS-on-diamond, obtained bonding a thinned to 25 μm CMOS Monolithic Active Pixel Sensor to a standard 500 μm pCVD diamond substrate, has been proposed and fabricated, allowing a highly segmented readout (10×10 μm pixel size) of the signal produced in the diamond substrate. The bonding between the two materials has been obtained using a new laser technique to deliver the needed energy at the interface. A biasing scheme has been adopted to polarize the diamond substrate to allow the charge transport inside the diamond without disrupting the functionalities of the CMOS Monolithic Active Pixel Sensor. The main concept of this class of devices is the capability of the charges generated in the diamond by ionizing radiation to cross the silicon–diamond interface and to be collected by the MAPS photodiodes. In this work we demonstrate that such passage occurs and measure its overall efficiency. This study has been carried out first calibrating the CMOS MAPS with monochromatic X-rays, and then testing the device with charged particles (electrons) either with and without biasing the diamond substrate, to compare the amount of signal collected.

Out of lab calibration of a rotating 2D scanner for 3D mapping

Science.gov (United States)

Koch, Rainer; Böttcher, Lena; Jahrsdörfer, Maximilian; Maier, Johannes; Trommer, Malte; May, Stefan; Nüchter, Andreas

2017-06-01

Mapping is an essential task in mobile robotics. To fulfil advanced navigation and manipulation tasks a 3D representation of the environment is required. Applying stereo cameras or Time-of-flight cameras (TOF cameras) are one way to archive this requirement. Unfortunately, they suffer from drawbacks which makes it difficult to map properly. Therefore, costly 3D laser scanners are applied. An inexpensive way to build a 3D representation is to use a 2D laser scanner and rotate the scan plane around an additional axis. A 3D point cloud acquired with such a custom device consists of multiple 2D line scans. Therefore the scanner pose of each line scan need to be determined as well as parameters resulting from a calibration to generate a 3D point cloud. Using external sensor systems are a common method to determine these calibration parameters. This is costly and difficult when the robot needs to be calibrated outside the lab. Thus, this work presents a calibration method applied on a rotating 2D laser scanner. It uses a hardware setup to identify the required parameters for calibration. This hardware setup is light, small, and easy to transport. Hence, an out of lab calibration is possible. Additional a theoretical model was created to test the algorithm and analyse impact of the scanner accuracy. The hardware components of the 3D scanner system are an HOKUYO UTM-30LX-EW 2D laser scanner, a Dynamixel servo-motor, and a control unit. The calibration system consists of an hemisphere. In the inner of the hemisphere a circular plate is mounted. The algorithm needs to be provided with a dataset of a single rotation from the laser scanner. To achieve a proper calibration result the scanner needs to be located in the middle of the hemisphere. By means of geometric formulas the algorithms determine the individual deviations of the placed laser scanner. In order to minimize errors, the algorithm solves the formulas in an iterative process. First, the calibration algorithm was

Laser system using ultra-short laser pulses

Science.gov (United States)

Dantus, Marcos [Okemos, MI; Lozovoy, Vadim V [Okemos, MI; Comstock, Matthew [Milford, MI

2009-10-27

A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

Airborne detection and mapping of oil spills, Grand Bahamas, February 1973

Energy Technology Data Exchange (ETDEWEB)

Devilliers, J N

1973-09-01

An airborne exercise is described employing various sensors to investigate their ability to detect and map Louisiana crude and naphtha oil spills, both by day and by night. It is shown that photographic, infrared scanning, and low light level television all have some ability to detect Louisiana crude, but only infrared scanning detected naphtha. None of these sensors could identify the anomalies as oil. A laser fluorosensor showed promise in detecting oil at night. (Author) (GRA)

Application of Various Lasers to Laser Trimming Resistance System

Institute of Scientific and Technical Information of China (English)

SUN Ji-feng

2007-01-01

Though the laser trimming resistance has been an old laser machining industry for over 30 years, the development of technology brings new alternative lasers which can be used for the traditional machining. The paper describes application of various lasers to laser trimming resistance system including early traditional krypton arc lamp pumped Nd:YAG to laser, modern popular diode pumped solid state laser and the present advanced harmonic diode pumped solid state laser. Using the new alternative lasers in the laser trimming resistance system can dramatically improve the yields and equipment performance.

PROBABILISTIC MODEL OF LASER RANGE FINDER FOR THREE DIMENSIONAL GRID CELL IN CLOSE RANGE ENVIRONMENT

Directory of Open Access Journals (Sweden)

Hafiz b Iman

2016-04-01

Full Text Available The probabilistic model of a laser scanner presents an important aspect for simultaneous localization and map-building (SLAM. However, the characteristic of the beam of the laser range finder under extreme incident angles approaching 900 has not been thoroughly investigated. This research paper reports the characteristic of the density of the range value coming from a laser range finder under close range circumstances where the laser is imposed with a high incident angle. The laser was placed in a controlled environment consisting of walls at a close range and 1000 iteration of scans was collected. The assumption of normal density of the metrical data collapses when the beam traverses across sharp edges in this environment. The data collected also shows multimodal density at instances where the range has discontinuity. The standard deviation of the laser range finder is reported to average at 10.54 mm, with 0.96 of accuracy. This significance suggests that under extreme incident angles, a laser range finder reading behaves differently compared to normal distribution. The use of this information is crucial for SLAM activity in enclosed environments such as inside piping grid or other cluttered environments.KEYWORDS:   Hokuyo UTM-30LX; kernel density estimation; probabilistic model  

Assessing biomass based on canopy height profiles using airborne laser scanning data in eucalypt plantations

Directory of Open Access Journals (Sweden)

André Gracioso Peres Silva

2015-12-01

Full Text Available This study aimed to map the stem biomass of an even-aged eucalyptus plantation in southeastern Brazil based on canopy height profile (CHPs statistics using wall-to-wall discrete return airborne laser scanning (ALS, and compare the results with alternative maps generated by ordinary kriging interpolation from field-derived measurements. The assessment of stem biomass with ALS data was carried out using regression analysis methods. Initially, CHPs were determined to express the distribution of laser point heights in the ALS cloud for each sample plot. The probability density function (pdf used was the Weibull distribution, with two parameters that in a secondary task, were used as explanatory variables to model stem biomass. ALS metrics such as height percentiles, dispersion of heights, and proportion of points were also investigated. A simple linear regression model of stem biomass as a function of the Weibull scale parameter showed high correlation (adj.R2 = 0.89. The alternative model considering the 30th percentile and the Weibull shape parameter slightly improved the quality of the estimation (adj.R2 = 0.93. Stem biomass maps based on the Weibull scale parameter doubled the accuracy of the ordinary kriging approach (relative root mean square error = 6 % and 13 %, respectively.

Comparison of space borne radar altimetry and airborne laser altimetry over sea ice in the Fram Strait

DEFF Research Database (Denmark)

Giles, K.A.; Hvidegaard, Sine Munk

2006-01-01

This paper describes the first comparison of satellite radar and airborne laser altimetry over sea ice. In order to investigate the differences between measurements from the two different instruments we explore the statistical properties of the data and determine reasonable scales in space and time...... at which to examine them. The resulting differences between the data sets show that the laser and the radar are reflecting from different surfaces and that the magnitude of the difference decreases with increasing surface air temperature. This suggests that the penetration depth of the radar signal......, into the snow, varies with temperature. The results also show the potential for computing Arctic wide snow depth maps by combining measurements from laser and radar altimeters....

New vistas in refractive laser beam shaping with an analytic design approach

Science.gov (United States)

Duerr, Fabian; Thienpont, Hugo

2014-05-01

Many commercial, medical and scientific applications of the laser have been developed since its invention. Some of these applications require a specific beam irradiance distribution to ensure optimal performance. Often, it is possible to apply geometrical methods to design laser beam shapers. This common design approach is based on the ray mapping between the input plane and the output beam. Geometric ray mapping designs with two plano-aspheric lenses have been thoroughly studied in the past. Even though analytic expressions for various ray mapping functions do exist, the surface profiles of the lenses are still calculated numerically. In this work, we present an alternative novel design approach that allows direct calculation of the rotational symmetric lens profiles described by analytic functions. Starting from the example of a basic beam expander, a set of functional differential equations is derived from Fermat's principle. This formalism allows calculating the exact lens profiles described by Taylor series coefficients up to very high orders. To demonstrate the versatility of this new approach, two further cases are solved: a Gaussian to at-top irradiance beam shaping system, and a beam shaping system that generates a more complex dark-hollow Gaussian (donut-like) irradiance profile with zero intensity in the on-axis region. The presented ray tracing results confirm the high accuracy of all calculated solutions and indicate the potential of this design approach for refractive beam shaping applications.

Laser optically pumped by laser-produced plasma

International Nuclear Information System (INIS)

Silfvast, W.T.; Wood, O.R. II.

1975-01-01

Laser solids, liquids and gases are pumped by a new technique in which the output from an efficient molecular laser, such as a CO 2 laser, ionizes a medium, such as xenon, into a generally cylindrical plasma volume, in proximity to the pumped laser body. Breakdown yields a visible and ultraviolet-radiation-emitting plasma in that volume to pump the laser body. The spectral radiance of the plasma is significantly higher than that produced by a dc-discharge-heated plasma at nearly all wavelengths in the plasma spectrum. The risetime of radiation from the laser-produced plasma can also be significantly shorter than that of a dc heated plasma. A further advantage resides in the fact that in some applications the attenuating walls needed by flashlamps may be eliminated with the result that laser threshold is more readily reached. Traveling wave excitation may be provided by oblique incidence of the pumping laser beam through the ionizable medium to create sequential ionization of portions of that medium along the length of the pumped laser body. (auth)

Diode laser-pumped Ho:YLF laser

International Nuclear Information System (INIS)

Hemmati, H.

1987-01-01

The author reports laser action in Ho:YLF at 2.06 μm following optical pumping with a cw diode laser array. Diode laser-pumped Nd-YAG and Ho:YAG have been reported recently. Lasers with a wavelength of 2 μm have medical and optical communication applications. The diode laser light is focused with a 60-mm focal length lens onto the YLF crystal. A high-reflectivity mirror with 100-mm radius of curvature was used as the output coupler. The lasing threshold was at 5 mWof incident power. This is higher than expected considering that a high reflector was used as the output coupler. However, a more uniform cooling of the crystal is expected to lower the lasing threshold. With 100 mW of pump power coupled into the crystal, --20 mW of 2-μm radiation was observed from this unoptimized setup. The 2-μm laser output is highly sensitive to output coupler alignment, YLF crystal temperature, and pump laser wavelength. The 20% optical conversion efficiency achieved in his preliminary measurements is expected to be improved by better crystal cooling, proper matching of laser wavelength to crystal absorption, variations in the concentration of Ho and sensitizers and use of a proper output coupler. A study of the parameters mentioned above and the effect of crystal temperature on the laser output is under way

BENCHMARKING MOBILE LASER SCANNING SYSTEMS USING A PERMANENT TEST FIELD

Directory of Open Access Journals (Sweden)

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

Lasers for the SILVA laser isotope separation process

International Nuclear Information System (INIS)

Lapierre, Y.

1997-01-01

The main principles of the laser isotope separation process for the production of enriched uranium at lower cost, are reviewed and the corresponding optimal laser characteristics are described. The development of the SILVA laser isotope separation process involved researches in the various domains of pump lasers, dye lasers, laser and optics systems and two test facilities for the feasibility studies which are expected for 1997

Ultrafast laser writing of optical waveguides in ceramic Yb:YAG: a study of thermal and non-thermal regimes

Energy Technology Data Exchange (ETDEWEB)

Benayas, A.; Jaque, D. [Universidad Autonoma de Madrid, Departamento de Fisica de Materiales, Madrid (Spain); Silva, W.F.; Jacinto, C. [Universidade Federal de Alagoas, Grupo de Fotonica e Fluidos Complexos, Instituto de Fisica, Maceio, Alagoas (Brazil); Rodenas, A.; Thomsom, R.R.; Psaila, N.D.; Reid, D.T.; Kar, A.K. [Heriot-Watt University, School of Engineering and Physical Sciences, Edinburgh (United Kingdom); Vazquez de Aldana, J. [Universidad de Salamanca, Grupo de Optica, Departamento de Fisica Aplicada, Facultad de Ciencias Fisicas, Salamanca (Spain); Chen, F.; Tan, Y. [Shandong University, School of Physics, Jinan (China); Torchia, G.A. [CONICET-CIC, Centro de Investigaciones Opticas, La Plata (Argentina)

2011-07-15

We report the improvement of ultrafast laser written optical waveguides in Yb:YAG ceramics by tailoring the presence of heat accumulation effects. From a combination of ytterbium micro-luminescence and micro-Raman structural analysis, maps of lattice defects and stress fields have been obtained. We show how laser annealing can strongly reduce the concentration of defects and also reduce compressive stress, leading to an effective 50% reduction in the propagation losses and to more extended and symmetric propagation modes. (orig.)

Quality assessment and comparison of smartphone, airborne and leica c10 laser scanner based point clouds

NARCIS (Netherlands)

Sirmacek, B.; Lindenbergh, R.C.; Wang, J.

2016-01-01

3D urban models are valuable for urban map generation, environment monitoring, safety planning and educational purposes. For 3D measurement of urban structures, generally airborne laser scanning sensors or multi-view satellite images are used as a data source. However, close-range sensors (such as

California State Waters Map Series: offshore of Santa Barbara, California

Science.gov (United States)

Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Greene, H. Gary; Krigsman, Lisa M.; Kvitek, Rikk G.; Dieter, Bryan E.; Endris, Charles A.; Seitz, Gordon G.; Sliter, Ray W.; Erdey, Mercedes D.; Gutierrez, Carlos I.; Wong, Florence L.; Yoklavich, Mary M.; Draut, Amy E.; Hart, Patrick E.; Conrad, James E.; Cochran, Susan A.; Johnson, Samuel Y.; Cochran, Susan A.

2013-01-01

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Santa Barbara map area lies within the central Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges province, and geodetic studies indicate that the region is presently undergoing north-south shortening. Uplift rates (as much as 2.2 mm/yr) that are based on studies of onland marine terraces provide further evidence of significant shortening. The city of Santa Barbara, the main coastal population center in the map area, is part of a contiguous urban area that extends from Carpinteria to Goleta. This urban area was developed on the coalescing alluvial surfaces, uplifted marine terraces, and low hills that lie south of the east-west-trending Santa Ynez Mountains. Several beaches line the actively

California State Waters Map Series—Offshore of Santa Cruz, California

Science.gov (United States)

Cochrane, Guy R.; Dartnell, Peter; Johnson, Samuel Y.; Erdey, Mercedes D.; Golden, Nadine E.; Greene, H. Gary; Dieter, Bryan E.; Hartwell, Stephen R.; Ritchie, Andrew C.; Finlayson, David P.; Endris, Charles A.; Watt, Janet T.; Davenport, Clifton W.; Sliter, Ray W.; Maier, Katherine L.; Krigsman, Lisa M.; Cochrane, Guy R.; Cochran, Susan A.

2016-03-24

IntroductionIn 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow subsurface geology.The Offshore of Santa Cruz map area is located in central California, on the Pacific Coast about 98 km south of San Francisco. The city of Santa Cruz (population, about 63,000), the largest incorporated city in the map area and the county seat of Santa Cruz County, lies on uplifted marine terraces between the shoreline and the northwest-trending Santa Cruz Mountains, part of California’s Coast Ranges. All of California’s State Waters in the map area is part of the Monterey Bay National Marine Sanctuary.The map area is cut by an offshore section of the San Gregorio Fault Zone, and it lies about 20 kilometers southwest of the San Andreas Fault Zone. Regional folding and uplift along the coast has been attributed to a westward bend in the San Andreas Fault Zone and to right-lateral movement along the San Gregorio Fault Zone. Most of the coastal zone is characterized by low, rocky cliffs and sparse, small pocket beaches backed by low, terraced hills. Point Santa Cruz, which forms the north edge of Monterey Bay, provides protection for the beaches in the easternmost part of the map area by sheltering them from the predominantly northwesterly waves.The shelf in the map area is underlain by variable amounts (0 to 25 m) of

California State Waters Map Series--Offshore of Ventura, California

Science.gov (United States)

Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Kvitek, Rikk G.; Greene, H. Gary; Krigsman, Lisa M.; Endris, Charles A.; Seitz, Gordon G.; Gutierrez, Carlos I.; Sliter, Ray W.; Erdey, Mercedes D.; Wong, Florence L.; Yoklavich, Mary M.; Draut, Amy E.; Hart, Patrick E.; Johnson, Samuel Y.; Cochran, Susan A.

2013-01-01

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Ventura map area lies within the Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges, and the region is presently undergoing north-south shortening. The city of Ventura is the major cultural center in the map area. The Ventura River cuts through Ventura, draining the Santa Ynez Mountains and the coastal hills north of Ventura. Northwest of Ventura, the coastal zone is a narrow strip containing highway and railway transportation corridors and a few small residential clusters. Rincon Island, an island constructed for oil and gas production, lies offshore of Punta Gorda. Southeast of Ventura, the coastal zone consists of the mouth and broad, alluvial plains of the Santa Clara River

Residual stresses in laser direct metal deposited Waspaloy

Energy Technology Data Exchange (ETDEWEB)

Moat, R.J., E-mail: richard.moat@manchester.ac.uk [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Pinkerton, A.J.; Li, L. [Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, M60 1QD (United Kingdom); Withers, P.J.; Preuss, M. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom)

2011-03-15

Research highlights: {yields} Neutron diffraction and the contour method show good agreement. {yields} Tensile stresses found parallel to the surfaces. {yields} Compressive stresses within the bulk of the structures. {yields} Residual stress weakly dependent on the laser pulse parameters. {yields} Maximum tensile residual stress unaffected across range of pulse parameters used. - Abstract: This paper reports a study into the effect of laser pulse length and duty cycle on the residual stress distributions in multi-track laser direct metal deposits of Waspaloy onto an Inconel 718 substrate. The residual stresses have been evaluated using neutron diffraction and the contour method, while electron microscopy and micro hardness indentation have been used to map the concomitant microstructural variation. In all cases, near the tops of the deposited walls, the longitudinal stresses are tensile towards the mid-length of the wall, while the stresses perpendicular to the substrate are negligible. By contrast near the base of the walls, the stresses along the direction of deposition are small, while the stresses perpendicular to the substrate are compressive at the centre and tensile towards the ends. Consistent with previous observations, the stresses parallel to free surfaces are tensile, balanced by compressive stresses in the interior (an inverse quench stress profile). These profiles have been found to be weakly dependent on the laser pulse parameters, most notably an increase in tensile stress gradient with increasing duty cycle, but the maximum residual stresses are largely unaffected. Furthermore, microstructural analysis has shown that the effect of laser pulse parameters on grain morphology in multi-track thick walls is less marked than previously reported for single-track wall structures.

Residual stresses in laser direct metal deposited Waspaloy

International Nuclear Information System (INIS)

Moat, R.J.; Pinkerton, A.J.; Li, L.; Withers, P.J.; Preuss, M.

2011-01-01

Research highlights: → Neutron diffraction and the contour method show good agreement. → Tensile stresses found parallel to the surfaces. → Compressive stresses within the bulk of the structures. → Residual stress weakly dependent on the laser pulse parameters. → Maximum tensile residual stress unaffected across range of pulse parameters used. - Abstract: This paper reports a study into the effect of laser pulse length and duty cycle on the residual stress distributions in multi-track laser direct metal deposits of Waspaloy onto an Inconel 718 substrate. The residual stresses have been evaluated using neutron diffraction and the contour method, while electron microscopy and micro hardness indentation have been used to map the concomitant microstructural variation. In all cases, near the tops of the deposited walls, the longitudinal stresses are tensile towards the mid-length of the wall, while the stresses perpendicular to the substrate are negligible. By contrast near the base of the walls, the stresses along the direction of deposition are small, while the stresses perpendicular to the substrate are compressive at the centre and tensile towards the ends. Consistent with previous observations, the stresses parallel to free surfaces are tensile, balanced by compressive stresses in the interior (an inverse quench stress profile). These profiles have been found to be weakly dependent on the laser pulse parameters, most notably an increase in tensile stress gradient with increasing duty cycle, but the maximum residual stresses are largely unaffected. Furthermore, microstructural analysis has shown that the effect of laser pulse parameters on grain morphology in multi-track thick walls is less marked than previously reported for single-track wall structures.

Development of frequency tunable Ti:sapphire laser and dye laser pumped by a pulsed Nd:YAG laser

International Nuclear Information System (INIS)

Yi, Jong Hoon; Horn, Roland; Wendt, K.

2001-01-01

We investigated lasing characteristics of two kinds of tunable laser, liquid dye laser and solid Ti:sapphire crystal laser, pumped by high pulse repetition rate Nd:YAG laser. Dye laser showed drastically reduced pulsewidth compared with that of pump laser and it also contained large amount of amplified spontaneous emission. Ti:sapphire laser showed also reduced pulsewidth. But, the laser conversion pump laser and Ti:sapphire laser pulse, we used a Brewster-cut Pockel's cell for Q-switching. The laser was frequency doubled by a type I BBO crystal outside of the cavity.

Generalized surficial geologic map of the Fort Irwin area, San Bernadino: Chapter B in Geology and geophysics applied to groundwater hydrology at Fort Irwin, California

Science.gov (United States)

Miller, David M.; Menges, Christopher M.; Lidke, David J.; Buesch, David C.

2014-01-01

The geology and landscape of the Fort Irwin area, typical of many parts of the Mojave Desert, consist of rugged mountains separated by broad alluviated valleys that form the main coarse-resolution features of the geologic map. Crystalline and sedimentary rocks, Mesozoic and older in age, form most of the mountains with lesser accumulations of Miocene sedimentary and volcanic rocks. In detail, the area exhibits a fairly complex distribution of surficial deposits resulting from diverse rock sources and geomorphology that has been driven by topographic changes caused by recent and active faulting. Depositional environments span those typical of the Mojave Desert: alluvial fans on broad piedmonts, major intermittent streams along valley floors, eolian sand dunes and sheets, and playas in closed valleys that lack through-going washes. Erosional environments include rocky mountains, smooth gently sloping pediments, and badlands in readily eroded sediment. All parts of the landscape, from regional distribution of mountains, valleys, and faults to details of degree of soil development in surface materials, are portrayed by the surficial geologic map. Many of these attributes govern infiltration and recharge, and the surface distribution of permeable rock units such as Miocene sedimentary and volcanic rocks provides a basis for evaluating potential groundwater storage. Quaternary faults are widespread in the Fort Irwin area and include sinistral, east-striking faults that characterize the central swath of the area and the contrasting dextral, northwest-striking faults that border the east and west margins. Bedrock distribution and thickness of valley-fill deposits are controlled by modern and past faulting, and faults on the map help to identify targets for groundwater exploration.

Integrated Surveyng with Mobile Mapping System, Egnos, Ntrk and Laser Technologies in the Park "NINNI CASSARA" in Palermo

Science.gov (United States)

Dardanelli, G.; Carella, M.

2013-09-01

This article summarizes the experience gained between 2012 and 2013 by the department of "Civil Engineering, Environmental, Aerospace and Materials" of University of Palermo on the integrated survey of Ninni Park Cassara Park in Palermo and the subsequent testing of methods, tools and techniques based on current research regarding the acquisition and processing of GNSS (Global Navigation Satellite System) data and laser-scanner. A fruitful time dedicated to the design of the survey has allowed us to become aware of the critical issues that the site presents because of its vast extent and diversity in size and number of the elements of which it is composed. The work has been addressed thematizing the elements to detect and selecting the techniques as possible economic and fast to be applied in the acquisition phase. Sixteen control points evenly distributed within the site were first materialized and detected with static GNSS mode. The survey mode NRTK (Network Real Time Kinematic) of the elements was then planned and carried out. The survey of the numerous planting was done by exploiting the mode with EGNOS (European Geostationary Navigation Overlay Service) correction. We continued the work experimenting with MMS (Mobile Mapping System) acquisition through which it was possible to acquire data on the morphology of the terrain, the conditions of the state of footpaths, buildings and on the distribution of street furniture. The point clouds obtained were subjected to both automatic and manual procedures to verify, finally, their actual descriptive possibilities of real forms detected.

Experimental Research on Selective Laser Melting AlSi10Mg Alloys: Process, Densification and Performance

Science.gov (United States)

Chen, Zhen; Wei, Zhengying; Wei, Pei; Chen, Shenggui; Lu, Bingheng; Du, Jun; Li, Junfeng; Zhang, Shuzhe

2017-12-01

In this work, a set of experiments was designed to investigate the effect of process parameters on the relative density of the AlSi10Mg parts manufactured by SLM. The influence of laser scan speed v, laser power P and hatch space H, which were considered as the dominant parameters, on the powder melting and densification behavior was also studied experimentally. In addition, the laser energy density was introduced to evaluate the combined effect of the above dominant parameters, so as to control the SLM process integrally. As a result, a high relative density (> 97%) was obtained by SLM at an optimized laser energy density of 3.5-5.5 J/mm2. Moreover, a parameter-densification map was established to visually select the optimum process parameters for the SLM-processed AlSi10Mg parts with elevated density and required mechanical properties. The results provide an important experimental guidance for obtaining AlSi10Mg components with full density and gradient functional porosity by SLM.

Forest Biomass Mapping From Lidar and Radar Synergies

Science.gov (United States)

Sun, Guoqing; Ranson, K. Jon; Guo, Z.; Zhang, Z.; Montesano, P.; Kimes, D.

2011-01-01

The use of lidar and radar instruments to measure forest structure attributes such as height and biomass at global scales is being considered for a future Earth Observation satellite mission, DESDynI (Deformation, Ecosystem Structure, and Dynamics of Ice). Large footprint lidar makes a direct measurement of the heights of scatterers in the illuminated footprint and can yield accurate information about the vertical profile of the canopy within lidar footprint samples. Synthetic Aperture Radar (SAR) is known to sense the canopy volume, especially at longer wavelengths and provides image data. Methods for biomass mapping by a combination of lidar sampling and radar mapping need to be developed. In this study, several issues in this respect were investigated using aircraft borne lidar and SAR data in Howland, Maine, USA. The stepwise regression selected the height indices rh50 and rh75 of the Laser Vegetation Imaging Sensor (LVIS) data for predicting field measured biomass with a R(exp 2) of 0.71 and RMSE of 31.33 Mg/ha. The above-ground biomass map generated from this regression model was considered to represent the true biomass of the area and used as a reference map since no better biomass map exists for the area. Random samples were taken from the biomass map and the correlation between the sampled biomass and co-located SAR signature was studied. The best models were used to extend the biomass from lidar samples into all forested areas in the study area, which mimics a procedure that could be used for the future DESDYnI Mission. It was found that depending on the data types used (quad-pol or dual-pol) the SAR data can predict the lidar biomass samples with R2 of 0.63-0.71, RMSE of 32.0-28.2 Mg/ha up to biomass levels of 200-250 Mg/ha. The mean biomass of the study area calculated from the biomass maps generated by lidar- SAR synergy 63 was within 10% of the reference biomass map derived from LVIS data. The results from this study are preliminary, but do show the

A multi-wavelength (u.v. to visible) laser system for early detection of oral cancer

Science.gov (United States)

Najda, S. P.; Perlin, P.; Leszczyński, M.; Slight, T. J.; Meredith, W.; Schemmann, M.; Moseley, H.; Woods, J. A.; Valentine, R.; Kalra, S.; Mossey, P.; Theaker, E.; Macluskey, M.; Mimnagh, G.; Mimnagh, W.

2015-03-01

A multi-wavelength (360nm - 440nm), real-time Photonic Cancer Detector (PCD) optical system based on GaN semiconductor laser technology is outlined. A proof of concept using blue laser technology for early detection of cancer has already been tested and proven for esophageal cancer. This concept is expanded to consider a wider range of wavelengths and the PCD will initially be used for early diagnosis of oral cancers. The PCD creates an image of the oral cavity (broad field white light detection) and maps within the oral cavity any suspicious lesions with high sensitivity using a narrow field tunable detector.

Baseline Design and Performance Analysis of Laser Altimeter for Korean Lunar Orbiter

Directory of Open Access Journals (Sweden)

Hyung-Chul Lim

2016-09-01

Full Text Available Korea’s lunar exploration project includes the launching of an orbiter, a lander (including a rover, and an experimental orbiter (referred to as a lunar pathfinder. Laser altimeters have played an important scientific role in lunar, planetary, and asteroid exploration missions since their first use in 1971 onboard the Apollo 15 mission to the Moon. In this study, a laser altimeter was proposed as a scientific instrument for the Korean lunar orbiter, which will be launched by 2020, to study the global topography of the surface of the Moon and its gravitational field and to support other payloads such as a terrain mapping camera or spectral imager. This study presents the baseline design and performance model for the proposed laser altimeter. Additionally, the study discusses the expected performance based on numerical simulation results. The simulation results indicate that the design of system parameters satisfies performance requirements with respect to detection probability and range error even under unfavorable conditions.

Operation regimes of a dielectric laser accelerator

Science.gov (United States)

Hanuka, Adi; Schächter, Levi

2018-04-01

We investigate three operation regimes in dielectric laser driven accelerators: maximum efficiency, maximum charge, and maximum loaded gradient. We demonstrate, using a self-consistent approach, that loaded gradients of the order of 1 to 6 [GV/m], efficiencies of 20% to 80%, and electrons flux of 1014 [el/s] are feasible, without significant concerns regarding damage threshold fluence. The latter imposes that the total charge per squared wavelength is constant (a total of 106 per μm2). We conceive this configuration as a zero-order design that should be considered for the road map of future accelerators.

Photonic bandgap fiber lasers and multicore fiber lasers for next generation high power lasers

DEFF Research Database (Denmark)

Shirakawa, A.; Chen, M.; Suzuki, Y.

2014-01-01

Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA....

Dissociation and ionization of molecular ions by ultra-short intense laser pulses probed by coincidence 3D momentum imaging

International Nuclear Information System (INIS)

Ben-Itzhak, Itzik; Wang, Pengqian; Xia, Jiangfan; Max Sayler, A.; Smith, Mark A.; Maseberg, J.W.; Carnes, Kevin D.; Esry, Brett D.

2005-01-01

We have experimentally explored laser-induced dissociation and ionization of diatomic molecular ions using coincidence 3D momentum imaging. The vibrationally excited molecular ion beam (4-8 keV) is crossed by an ultrafast intense laser beam (28-200 fs, 10 13 -10 14 W/cm 2 ). The resulting fragments are recorded in coincidence by a time and position-sensitive detector. Complete angular distributions and kinetic energy release maps are reconstructed from the measured dissociation-momentum vectors. The angular distribution of the H + + H fragments was found to be strongly correlated to their kinetic energy release upon dissociation. Low KER was associated with very narrow angular distributions and high KER with distributions peaking away from the laser polarization. Ionization was found to be smaller than dissociation and increased with laser intensity. The H + + H + fragments have a very narrow angular distribution along the laser polarization

3D Surface Mapping of Capsule Fill-Tube Assemblies used in Laser-Driven Fusion Targets

Energy Technology Data Exchange (ETDEWEB)

Buice, E S; Alger, E T; Antipa, N A; Bhandarkar, S D; Biesiada, T A; Conder, A D; Dzenitis, E G; Flegel, M S; Hamza, A V; Heinbockel, C L; Horner, J; Johnson, M A; Kegelmeyer, L M; Meyer, J S; Montesanti, R C; Reynolds, J L; Taylor, J S; Wegner, P J

2011-02-18

This paper presents the development of a 3D surface mapping system used to measure the surface of a fusion target Capsule Fill-Tube Assembly (CFTA). The CFTA consists of a hollow Ge-doped plastic sphere, called a capsule, ranging in outer diameter between 2.2 mm and 2.6 mm and an attached 150 {micro}m diameter glass-core fill-tube that tapers down to a 10{micro} diameter at the capsule. The mapping system is an enabling technology to facilitate a quality assurance program and to archive 3D surface information of each capsule used in fusion ignition experiments that are currently being performed at the National Ignition Facility (NIF). The 3D Surface Mapping System is designed to locate and quantify surface features with a height of 50 nm and 300 nm in width or larger. Additionally, the system will be calibrated such that the 3D measured surface can be related to the capsule surface angular coordinate system to within 0.25 degree (1{sigma}), which corresponds to approximately 5 {micro}m linear error on the capsule surface.

3D Surface Mapping of Capsule Fill-Tube Assemblies used in Laser-Driven Fusion Targets

International Nuclear Information System (INIS)

Buice, E.S.; Alger, E.T.; Antipa, N.A.; Bhandarkar, S.D.; Biesiada, T.A.; Conder, A.D.; Dzenitis, E.G.; Flegel, M.S.; Hamza, A.V.; Heinbockel, C.L.; Horner, J.; Johnson, M.A.; Kegelmeyer, L.M.; Meyer, J.S.; Montesanti, R.C.; Reynolds, J.L.; Taylor, J.S.; Wegner, P.J.

2011-01-01

This paper presents the development of a 3D surface mapping system used to measure the surface of a fusion target Capsule Fill-Tube Assembly (CFTA). The CFTA consists of a hollow Ge-doped plastic sphere, called a capsule, ranging in outer diameter between 2.2 mm and 2.6 mm and an attached 150 (micro)m diameter glass-core fill-tube that tapers down to a 10(micro) diameter at the capsule. The mapping system is an enabling technology to facilitate a quality assurance program and to archive 3D surface information of each capsule used in fusion ignition experiments that are currently being performed at the National Ignition Facility (NIF). The 3D Surface Mapping System is designed to locate and quantify surface features with a height of 50 nm and 300 nm in width or larger. Additionally, the system will be calibrated such that the 3D measured surface can be related to the capsule surface angular coordinate system to within 0.25 degree (1σ), which corresponds to approximately 5 (micro)m linear error on the capsule surface.

Microstructure and mechanical behavior of pulsed laser surface melted AISI D2 cold work tool steel

International Nuclear Information System (INIS)

Yasavol, N.; Abdollah-zadeh, A.; Ganjali, M.; Alidokht, S.A.

2013-01-01

Highlights: ► Melted zone contained fine dendrites in the bottom and equiaxed grains on the top. ► Microstructural refinements of PLSM led to microhardness enhancement. ► Higher scanning rate and lower laser energy were more effective to refine the microstructure. - Abstract: D2 cold work tool steel (CWTS) was subjected to pulse laser surface melting (PLSM) at constant frequency of 20 Hz Nd: YAG laser with different energies, scanning rate and pulse durations radiated to the surface. Characterizing the PLSM, with optical and field emission scanning electron microscopy, electron backscattered diffraction and surface hardness mapping technique was used to evaluate the microhardness and mechanical behavior of different regions of melting pool. Increasing laser energy and reducing the laser scanning rate results in deeper melt pool formation. Moreover, PLSM has led to entirely dissolution of the carbides and re-solidification of cellular/dendritic structure of a fine scale surrounded by a continuous interdendritic network. This caused an increase in surface microhardness, 2–4 times over that of the base metal.

Microstructure and mechanical behavior of pulsed laser surface melted AISI D2 cold work tool steel

Energy Technology Data Exchange (ETDEWEB)

Yasavol, N. [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Abdollah-zadeh, A., E-mail: zadeh@modares.ac.ir [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Ganjali, M. [Materials and Energy Research Center, P.O. Box 14155-4777, Karaj (Iran, Islamic Republic of); Alidokht, S.A. [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of)

2013-01-15

Highlights: Black-Right-Pointing-Pointer Melted zone contained fine dendrites in the bottom and equiaxed grains on the top. Black-Right-Pointing-Pointer Microstructural refinements of PLSM led to microhardness enhancement. Black-Right-Pointing-Pointer Higher scanning rate and lower laser energy were more effective to refine the microstructure. - Abstract: D2 cold work tool steel (CWTS) was subjected to pulse laser surface melting (PLSM) at constant frequency of 20 Hz Nd: YAG laser with different energies, scanning rate and pulse durations radiated to the surface. Characterizing the PLSM, with optical and field emission scanning electron microscopy, electron backscattered diffraction and surface hardness mapping technique was used to evaluate the microhardness and mechanical behavior of different regions of melting pool. Increasing laser energy and reducing the laser scanning rate results in deeper melt pool formation. Moreover, PLSM has led to entirely dissolution of the carbides and re-solidification of cellular/dendritic structure of a fine scale surrounded by a continuous interdendritic network. This caused an increase in surface microhardness, 2-4 times over that of the base metal.

Laser power sources and laser technology for accelerators

International Nuclear Information System (INIS)

Lowenthal, D.

1986-01-01

The requirements on laser power sources for advanced accelerator concepts are formidable. These requirements are driven by the need to deliver 5 TeV particles at luminosities of 10/sup 33/ - 10/sup 34/ cm/sup -2/ sec/sup -1/. Given that optical power can be transferred efficiently to the particles these accelerator parameters translate into single pulse laser output energies of several kilojoules and rep rates of 1-10 kHz. The average laser output power is then 10-20 MW. Larger average powers will be needed if efficient transfer proves not to be possible. A laser plant of this magnitude underscores the importance of high wall plug efficiency and reasonable cost in $/Watt. The interface between the laser output pulse format and the accelerator structure is another area that drives the laser requirements. Laser accelerators break up into two general architectures depending on the strength of the laser coupling. For strong coupling mechanisms, the architecture requires many ''small'' lasers powering the accelerator in a staged arrangement. For the weak coupling mechanisms, the architecture must feature a single large laser system whose power must be transported along the entire accelerator length. Both of these arrangements have demanding optical constraints in terms of phase matching sequential stages, beam combining arrays of laser outputs and optimizing coupling of laser power in a single accelerating stage

Laser pumped lasers for isotope separation

International Nuclear Information System (INIS)

Fry, S.M.

1976-01-01

A study of the isotope separation laser requirements reveals that high pressure polyatomic molecular gas laser pumped lasers can attain the necessary characteristics including tunability, energy output, pulse width, and repetition rate. The results of a search, made for molecules meeting the appropriate requirements for one of several pump schemes utilizing a CO 2 laser and with output in the 12 μm or 16μm wavelength range, are presented. Several methods of pumping are reviewed and two novel pump schemes are presented. A laser pumped laser device design is given, and operation of this device and associated diagnostic equipment is confirmed by repeating experiments in OCS and NH 3 . The results of OCS laser experiments show that an improvement in pump rate and output per unit length is obtained with the device, using a wedged transverse pumping scheme. A new multi-line laser system in NH 3 pumped by a TEA CO 2 laser is reported. More than forty transitions spanning the wavelength range of 9.2 to 13.8 μm are observed and identified. A strong output at 12.08 μm is one of the closest lines yet found to the required laser isotope separation wavelength. Far infrared emission near 65 μm is observed and is responsible for populating levels which lase in pure ammonia near 12.3 μm. Buffer gas (e.g., N 2 or He) pressures of approximately 40--800 torr cause energy transfer by collision-induced rotationaltransitions from the pumped antisymmetric to the lasing symmetric levels in the nu 2 = 1 band of ammonia. Most of the observed lines are aP(J,K) transitions which originate from the nu 2 /sup s/ band. Measurements of the pressure dependence of the laser output shows that some lines lase at pressures greater than one atmosphere. Transient behavior of the 12.08 μm line is calculated from a simplified analytic model and these calculations are compared to the experimental results

Future prospects of laser diodes and fiber lasers

International Nuclear Information System (INIS)

Ueda, Ken-ichi

2000-01-01

For the next century we should develop new concepts for coherent control of light generation and propagation. Owing to the recent development of ultra fine structures in semiconductor lasers, fiber lasers, and various kinds of waveguide structure, we can make optical devices which control the light propagation artificially. But, the phase locking and phase control of multiple laser oscillators are one of the most important directions of laser science and technology. The coherent summation has been a dream of laser since 1960. Is it possible to solve this old and quite challenging problem for laser science? This is also a very basic concept because the laser action based on the stimulated emission is the process of coherent summation of huge number of photons emitted from individual atoms. In this paper, I discuss the fundamental direction of laser research in the next ten or twenty years. The active optics and laser technology should be combined intrinsically in near future. (author)

Dense range map reconstruction from a versatile robotic sensor system with an active trinocular vision and a passive binocular vision.

Science.gov (United States)

Kim, Min Young; Lee, Hyunkee; Cho, Hyungsuck

2008-04-10

One major research issue associated with 3D perception by robotic systems is the creation of efficient sensor systems that can generate dense range maps reliably. A visual sensor system for robotic applications is developed that is inherently equipped with two types of sensor, an active trinocular vision and a passive stereo vision. Unlike in conventional active vision systems that use a large number of images with variations of projected patterns for dense range map acquisition or from conventional passive vision systems that work well on specific environments with sufficient feature information, a cooperative bidirectional sensor fusion method for this visual sensor system enables us to acquire a reliable dense range map using active and passive information simultaneously. The fusion algorithms are composed of two parts, one in which the passive stereo vision helps active vision and the other in which the active trinocular vision helps the passive one. The first part matches the laser patterns in stereo laser images with the help of intensity images; the second part utilizes an information fusion technique using the dynamic programming method in which image regions between laser patterns are matched pixel-by-pixel with help of the fusion results obtained in the first part. To determine how the proposed sensor system and fusion algorithms can work in real applications, the sensor system is implemented on a robotic system, and the proposed algorithms are applied. A series of experimental tests is performed for a variety of configurations of robot and environments. The performance of the sensor system is discussed in detail.

AIRBORNE LASER BATHYMETRY FOR DOCUMENTATION OF SUBMERGED ARCHAEOLOGICAL SITES IN SHALLOW WATER

Directory of Open Access Journals (Sweden)

M. Doneus

2015-04-01

Full Text Available Knowledge of underwater topography is essential to the understanding of the organisation and distribution of archaeological sites along and in water bodies. Special attention has to be paid to intertidal and inshore zones where, due to sea-level rise, coastlines have changed and many former coastal sites are now submerged in shallow water. Mapping the detailed inshore topography is therefore important to reconstruct former coastlines, identify sunken archaeological structures and locate potential former harbour sites. However, until recently archaeology has lacked suitable methods to provide the required topographical data of shallow underwater bodies. Our research shows that airborne topo-bathymetric laser scanner systems are able to measure surfaces above and below the water table over large areas in high detail using very short and narrow green laser pulses, even revealing sunken archaeological structures in shallow water. Using an airborne laser scanner operating at a wavelength in the green visible spectrum (532 nm two case study areas in different environmental settings (Kolone, Croatia, with clear sea water; Lake Keutschach, Austria, with turbid water were scanned. In both cases, a digital model of the underwater topography with a planimetric resolution of a few decimeters was measured. While in the clear waters of Kolone penetration depth was up to 11 meters, turbid Lake Keutschach allowed only to document the upper 1.6 meters of its underwater topography. Our results demonstrate the potential of this technique to map submerged archaeological structures over large areas in high detail providing the possibility for systematic, large scale archaeological investigation of this environment.